Full text of “Bodily Changes In Pain Hunger Fear And Rage“
CO > CO > DO g]<OU 166534 >m > o: ~ 3J = CQ -< CO UNIVERSITY UBBLARY Call No. ' ( $"] / C 2. 1 > Accession No. // $1- $~ lkk This Hook should be returned on or before the d ate las Unarkw below, BODILY CHANGES IN PAIN, HUNGER, FEAR AND RAGE BODILY CHANGES IN PAIN, HUNGER, FEAR AND RAGE AX ACCOUNT OF RECENT RE- SEARCHES INTO THE FUNCTION OF EMOTIONAL EXCITEMENT BY WALTER 11. CANNON, M.I)., C.B. GEORGE HIGr.INSON, PROH'SSOR Oh 1'IIYSlOLOGY IN HARVARD I MVLHSITY NEW YORK AND LONDON D. APPLETOX AM) COMPANY 1927 COPYRIGHT, 1015, 1920, BY D. APPLETON AND COMPANY Printed in the United States of America, TO MY COLLABORATORS IN THESE RESEARCHES DANIEL DE LA PAZ ALFRED T. SHOHL WADE 8. WRIGHT ARTHUR L. WASHBURN M^RY LYMAN LEONARD B. NICE CHARLES M. GRUBER HOWARD OSGOOD HORACE GRAY WALTER L. MENDENilALL WITH PLEASANT MEMORIES OF OUR WORK TOGETHER PREFACE Fear, rage and pain, and the pangs of hunger are all primitive experiences which human beings share with the lower animals. These experiences are properly classed as among the most powerful that determine the action of men and beasts. A knowledge of the conditions which attend these experiences, therefore, is of general and fundamental importance in the interpretation of behavior. During the past four years there has been conducted, in the Harvard Physiological Laboratory, a series of in- vestigations concerned with the bodily changes which occur in conjunction with pain, hunger and the major emotions. A group of remarkable alterations in the bodily economy have been discovered, all of which can reasonably be regarded as responses that are nicely adapted to the individual's welfare and preservation. Because these physiological adaptations are interesting both in themselves and in their interpretation, not only to physiologists and psychologists, but to others as well, it has seemed worth while to gather together in con- venient form the original accounts of the experiments, which have been published in various American medical and physiological journals. I have, however, attempted to arrange the results and discussions in an orderly and consecutive manner, and I have tried also to elim- vii Vlll PREFACE mate or incidentally to explain the technical terms, so that the exposition will be easily understood by any intelligent reader even though not trained in the med- ical sciences. My first interest in the conditions attending pain, hunger and strong emotional states was stimulated dur- ing the course of a previous series of researches on the motor activities of the alimentary canal. A summary of these researches appeared in 1911, under the title, "The Mechanical Factors of Digestion." The studies recorded in the present volume may be regarded as a natural sequence of observations on the influence of emotional states on the digestive process, which were reported in that volume. W. B. CANNON. Boston, Mass. CONTENTS CHAPTER I PAGES THE EFFECT OF THE EMOTIONS ON DIGESTION Emotions favorable to normal secretion of the digestive juices Emotions unfavorable to normal secretion of the digestive juices Emotions favorable and un- favorable to contractions of the stomach and in- testines The disturbing effect of pain on di- gestion 1-21 CIIAPTEK II THE GENERAL ORGANIZATION OF THE VIS- CERAt NERVES CONCERNED IN EMOTIONS The outlying neurones The three divisions of the out- lying neurones The extensive distribution of neu- rones of the "sympathetic" or thoracico-lumbar di- vision and their arrangement for diffuse action The arrangement of neurones of the cranial and sacral divisions for specific action The cranial division a conserver of bodily resources The sacral division a group of mechanisms for emptying The sympa- thetic division antagonistic to both the cranial and the sacral Neurones of the sympathetic division and adrenal secretion have the same action 22-39 ix x CONTENTS CHAPTEE III PAGES METHODS OF DEMONSTRATING ADRENAL SECRE- TION AND ITS NERVOUS CONTROL The evidence that splanchnic stimulation induces ad- renal secretion The question of adrenal secretion in emotional excitement The method of securing blood from near the adrenal veins The method of testing the blood for adrenin 40-51 CHAPTEE IV ADRENAL SECRETION IN STRONG EMOTIONS AND PAIN The evidence that adrenal secretion is increased in emo- tional excitement The evidence that adrenal secre- tion is increased by "painful" stimulation Confirma- tion of our results by other observers .... 52-65 CHAPTEE V THE INCREASE OF BLOOD SUGAR IN PAIN AND GREAT EMOTION Glycosuria from pain Emotional glycosuria The role of the adrenal glands in emotional glycosuria . 66-80 CHAPTEE VI IMPROVED CONTRACTION OF FATIGUED MUSCLE AFTER SPLANCHNIC STIMULATION OF THE ADRENAL GLAND The nerve-muscle preparation The splanchnic prepara- tion The effects of splanchnic stimulation on the contraction of fatigued muscle The first rise in the muscle record The prolonged rise in the muscle record The two factors: arterial pressure and adre- nal secretion 81-94 CONTENTS xi CHAPTER VII PAGES THE EFFECTS ON CONTRACTION OF FATIGUED MUSCLE OF VARYING THE ARTERIAL BLOOD PRESSURE The effect of increasing arterial pressure The effect of decreasing arterial pressure An explanation of the effects of varying the arterial pressure The value of increased arterial pressure in pain and strong emotion 95-109 CHAPTER VIII THE SPECIFIC R6LE OF ADRENIN IN COUNTER- ACTING THE EFFECTS OF FATIGUE Variations of the threshold stimulus as a measure of irritability The method of determining the threshold stimulus The lessening of neuro-muscular irrita- bility by fatigue The slow restoration of fatigued muscle to normal irritability by rest The quick res- toration of fatigued muscle to normal irritability by adrenin The evidence that the restorative ac- tion of adrenin is specific The point of action of adrenin in muscle 110-134 CHAPTER IX THE HASTENING OF THE COAGULATION OF BLOOD BY ADRENIN The graphic method of measuring the coagulation time The effects of subcutaneous injections of adrenin The effects of intravenous injections The hastening of coagulation by adrenin not a direct effect on the blood 135-160 CHAPTER X THE HASTENING OF COAGULATION OF BLOOD IN PAIN AND GREAT EMOTION Coagulation hastened by splanchnic stimulation Co- agulation not hastened by splanchnic stimulation if xii CONTENTS PAGES the adrenal glands are absent Coagulation hast- ened by "painful" stimulation Coagulation hastened in emotional excitement 161-183 f CHAPTEK XI THE UTILITY OF THE BODILY CHANGES IN PAIN AND GREAT EMOTION The reflex nature of bodily responses in pain and the major emotions, and the useful character of re- flexes The utility of the increased blood sugar as a source of muscular energy The utility of in- creased adrenin in the blood as an antidote to the effects of fatigue The question whether adrenin normally secreted inhibits the use of sugar in the body The vascular changes produced by adrenin favorable to supreme muscular exertion The changes in respiratory function also favorable to great effort The effects produced in asphyxia similar to those produced in pain and excitement The utility of rapid coagulation in preventing loss of blood . 184-214 CHAPTEK XII THE ENERGIZING INFLUENCE OF EMOTIONAL EX- CITEMENT "Reservoirs of power" The excitements and energies of competitive sports Frenzy and endurance in cere- monial and other dances The fierce emotions and struggles of battle The stimulating influence of witnesses and of music The feeling of power . 215-231 CHAPTER XIII THE NATURE OF HUNGER Appetite and hunger The sensation of hunger The theory that hunger is a general sensation Weak- ness of the assumptions underlying the theory that hunger is a general sensation Body need may exist without hunger The theory that hunger is of gen- CONTENTS mi . . PAGES eral origin does not explain the quick onset and the periodicity of the sensation The theory that hunger is of general origin does not explain the local refer- ence Hunger not due to emptiness of the stomach Hunger not due to hydrochloric acid in the empty stomach Hunger not due to turgescence of the gas- tric mucous membrane Hunger the result of con- tractions The "empty" stomach and intestines con- tract Observations suggesting that contractions cause hunger The concomitance of contractions and hunger in man 232-266 CHAPTER XIV THE INTERRELATIONS OF EMOTIONS Antagonism between emotions expressed in the sym- pathetic and in the cranial divisions of the auto- nomic system Antagonism between emotions ex- pressed in the sympathetic and in the sacral di- visions of the autonomic system The function of hunger The similarity of visceral effects in differ- ent strong emotions and suggestions as to its psy- chological significance 267-284 CHAPTER XV ALTERNATIVE SATISFACTIONS FOR THE FIGHT- ING EMOTIONS Support for the militarist estimate of the strength of the fighting emotions and instincts Growing op- position to the fighting emotions and instincts as displayed in war The desirability of preserving the martial virtues Moral substitutes for warfare Phy- sical substitutes for warfare The significance of in- ternational athletic competitions 285-301 A LIST OF PUBLISHED RESEARCHES FROM THE PHYSIOLOGICAL LABORATORY IN HARVARD UNIVERSITY 302-303 INDEX 305 BODILY CHANGES IN PAIN, HUNGER, FEAR AND RAGE CHAPTER I THE EFFECT OF THE EMOTIONS ON DIGESTION The doctrine of human development from sub- human, antecedents has done much to unravel the complex nature of man. As a means of interpre- tation this doctrine has been directed chiefly toward the solving of puzzles in the peculiarities of anatomical structure. Thus arrangements in the human body, which are without obvious util- ity, receive rational explanation as being vestiges of parts useful in or characteristic of remote an- cestors parts retained in man because of age- long racial inheritance. This mode of interpreta- tion has proved applicable also in accounting for functional peculiarities. Expressive actions and gestures the facial appearance in anger, for ex- ample observed in children and in widely dis- tinct races, are found to be innate, and are best explained as the retention in human beings of responses which are similar in character in lower animals. l 2 BODILY CHANGES From this point of view biology has contributed much to clarify our ideas regarding the motives of human behavior. The social philosophies ^hich prevailed during the past century either assumed that conduct was determined by a cal- culated search for pleasure and avoidance of pain or they ascribed it to a vague and undefined faculty named the conscience or the moral sense. Comparative study of the behavior of men and of lower animals under various circumstances, however, especially with the purpose of learning the source of prevailing impulses, is revealing the inadequacy of the theories of the older psychol- ogists. More and more it is appearing that in men of all races and in most of the higher ani- mals, the springs of action are to be found in the influence of certain emotions which express themselves in characteristic instinctive acts. The role which these fundamental responses in the higher organisms play in the bodily economy has received little attention. As a realm for in- vestigation the bodily changes in emotional ex- citement have been left by the physiologists to the philosophers and psychologists and to the students of natural history. These students, how- ever, have usually had too slight experience in the detailed examination of bodily functions to permit them to follow the clues which superficial observation might present. In consequence our EMOTIONS AND DIGESTION 3 knowledge of emotional states has been meagre. There are, of course, many surface manifesta- tions of excitement. The contraction of blood vessels with resulting pallor, the pouring out of "cold sweat," the stopping of saliva-flow so that the "tongue cleaves to the roof of the mouth," the dilation of the pupils, the rising of the hairs, the rapid beating of the heart, the hurried respira- tion, the trembling and twitching of the muscles, especially those about the lips all these bodily changes are well recognized accompaniments of pain and great emotional disturbance, such as fear, horror and deep disgust. But these dis- turbances of the even routine of life, which have been commonly noted, are mainly superficial and therefore readily observable. Even the increased rapidity of the heart beat is noted at the surface in the pulsing of the arteries. There are, how- ever, other organs, hidden deep in the body, which do not reveal so obviously as the struc- tures near or in the skin, the disturbances of action which attend states of intense feeling. Special methods must be used to determine whether these deep-lying organs also are included in the complex of an emotional* agitation. * In the use of the term "emotion" the meaning here is not restricted to violent affective states, but includes "feel- ings" and other affective experiences. At times, also, in order to avoid awkward expressions, the term is used in the popular manner, as if the "feeling" caused the bodily change. 4 BODILY CHANGES Among the organs that are affected to an im- portant degree by feelings are those concerned with digestion. And the relations of feelings to the activities of the alimentary canal are of par- ticular interest, because recent investigations have shown that not only are the first stages of the digestive process normally started by the pleasur- able taste and smell and sight of food, but also that pain and great emotional excitement can seriously interfere with the starting of the pro- cess or its continuation after it has been started. Thus there may be a conflict of feelings and of their bodily accompaniments a conflict the inter- esting bearing of which we shall consider later. EMOTIONS FAVORABLE TO NORMAL SECRETION OF THE DIGESTIVE JUICES The feelings or affective states favorable to the digestive functions have been studied fruit- fully by Pawlow, 1 of Petrograd, through in- genious experiments on dogs. By the use of care- ful surgical methods he was able to make a side pouch of a part of the stomach, the cavity of which was wholly separate from the main cavity in which the food was received. This pouch was supplied in a normal manner with nerves and blood vessels, and as it opened to the surface of the body, the amount and character of the gastric juice secreted by it under various conditions EMOTIONS AND DIGESTION 5 could be accurately determined. Secretion by that part of the stomach wall which was included in the pouch was representative of the secretory activities* of the entire stomach. The arrange- ment was particularly advantageous in providing the gastric juice unmixed with food. In some of the animals thus operated upon an opening was also made in the esophagus so that when the food was swallowed, it did not pass to the stom- ach but dropped out on the way. All the pleas- ures of eating were thus experienced, and there was no necessity of stopping because of a sense of fulness. This process was called "sham feed- ing." The well-being of these animals was care- fully attended to, they lived the normal life of dogs, and in the course of months and years be- came the pets of the laboratory. By means of sham feeding Pawlow showed that the chewing and swallowing of food which the dogs relished resulted, after a delay of about five minutes, in a flow of natural gastric juice from the side pouch of the stomach a flow which per- sisted as long as the dog chewed and swallowed the food, and continued for some time after eat- ing ceased. Evidently the presence of food in the stomach is not a prime condition for gastric secretion. And since the flow occurred only when the dogs had an appetite, and the material pre- sented to them was agreeable, the conclusion 6 BODILY CHANGES was justified that this was a true psychic secretion. The mere sight or smell of a favorite food may start the pouring out of gastric juice, as was noted many years ago by Bidder and Schmidt 2 in a hungry dog which had a fistulous opening through the body wall into the stomach. This observation, reported in 1852, was confirmed later by Schiff and also still later by Pawlow. That the mouth "waters" with a flow of saliva when palatable food is seen or smelled has long been such common knowledge that the expression, "It makes my mouth water," is at once recognized as the highest testimony to the attractiveness of an appetizing dish. That the stomach also "waters" in preparation for digesting the food which is to be taken is clearly proved by the above cited ob- servations on the dog. The importance of the initial psychic secretion of saliva for further digestion is indicated when, in estimating the function of taste for the pleas- ures of appetite, we realize that materials can be tasted only when dissolved in the mouth and thereby brought into relation with the taste or- gans. The saliva which "waters" the mouth as- sures the dissolving of dry but soluble food even when it is taken in large amount. The importance of the initial psychic secretion of gastric juice is made clear by the fact that con- EMOTIONS AND DIGESTION 7 tinuance of the flow of this juice during diges- tion is provided by the action of its acid or its digestive products on the mucous membrane of the pyloric end of the stomach, and that secre- tion of the pancreatic juice and bile are called forth by the action of this same acid on the mu- cous membrane of the duodenum. The proper starting of the digestive process, therefore, is conditioned by the satisfactions of the palate, and the consequent flow of the first digestive fluids. The facts brought out experimentally in studies on lower animals are doubtless true also of man. Not very infrequently, because of the accidental swallowing of corrosive substances, the esopha- gus is so injured that, when it heals, the sides grow together and the tube is closed. Under these circumstances an opening has to be made into the stomach through the side of the body and then the individual chews his food in the usual manner, but ejects it from his mouth into a tube which is passed through the gastric opening. The food thus goes from mouth to stomach through a tube outside the chest instead of inside the chest. As long ago as 1878, Eichet, 3 who had occasion to study a girl whose esophagus was closed and who was fed through a gastric fistula, reported that whenever the girl chewed or tasted a highly sapid substance, such as sugar or lemon juice, while the stomach was empty, there flowed 8 BODILY CHANGES from the fistula a considerable quantity of gastric juice. A number of later observers 4 have had similar cases in human beings, especially in chil- dren, and have reported in detail results which correspond remarkably with those obtained in the laboratory. Hornborg 4 found that when the little boy whom he studied chewed agreeable food a more or less active secretion of gastric juice invariably started, whereas the chewing of an indifferent substance, as gutta-percha, was fol- lowed by no secretion. All these observations clearly demonstrate that the normal flow of the first digestive fluids, the saliva and the gastric juice, is favored by the pleasurable feelings which accompany the taste and smell of food dur- ing mastication, or which are roused in anticipa- tion of eating when choice morsels are seen or smelled. These facts are of fundamental importance in the serving of food, especially when, through ill- ness, the appetite is fickle. The degree of dainti- ness with which nourishment is served, the little attentions to esthetic details the arrangement of the dishes, the small portions of food, the flower beside the plate all may holp to render food pleasing to the eye and savory to the nos- trils and may be the deciding factors in determin- ing whether the restoration of strength is to be- gin or not. EMOTIONS AND DIGESTION 9 EMOTIONS UNFAVORABLE TO THE NORMAL SECRETION OF THE DIGESTIVE JUICES \The conditions favorable to proper digestion are wholly abolished when unpleasant feelings such as vexation and worry and anxiety, or great emotions such as anger and fear, are allowed to prevail. This fact, so far as the salivary secre- tion is concerned, has long been known. The dry mouth of the anxious person called upon to speak in public is a common instance; and the "ordeal of rice," as employed in India, was a prac- tical utilization of the knowledge that excitement is capable of inhibiting the salivary flow. When several persons were suspected of crime, the con- secrated rice was given to them all to chew, and after a short time it was spit out upon the leaf of the sacred fig tree. If anyone ejected it dry, that was taken as proof that fear of being discovered had stopped the secretion, and consequently he was adjudged guilty. 5 What has long been recognized as true of the secretion of saliva has been proved true also of the secretion of gastric juice. For example, Ilornborg was unable to confirm in his little pa- tient with a gastric fistula the observation by Pawlow that when hunger is present the mere seeing of food results in a flow of gastric juice. Ilornborg explained the difference between his and Pawlow's results by the different ways in 10 BODILY CHANGES which the boy and the dogs faced the situation. When food was shown, but withheld, the hungry dogs were all eagerness to secure it, and the juice very soon began to flow. The boy, on the con- trary, became vexed when he could not eat at once, and began to cry; then no secretion ap- peared. Bogen also has reported the instance of a child with closed esophagus and gastric fistula, who sometimes fell into such a passion in con- sequence of vain hoping for food that the giving of the food, after the child was calmed, was not followed by any flow of the secretion. The inhibitory influence of excitement has also been seen in lower animals under laboratory con- ditions. Le Conte 6 declares that in studying gastric secretion it is necessary to avoid all cir- cumstances likely to provoke emotional reactions. In the fear which dogs manifest when first brought into strange surroundings he found that activity of the gastric glands may be completely suppressed. The suppression occurred even if the dog had eaten freely and was then disturbed as, for example, by being tied to a table. When the animals became accustomed to the experi- mental procedure, it no longer had an inhibitory effect. The studies of Bickel and Sasaki 7 con- firm and define more precisely this inhibitory effect of strong emotion on gastric secretion. They observed the inhibition on a dog with an EMOTIONS AND DIGESTION 11 esophageal fistula, and with a side pouch of the stomach, which, as in Pawlow's experiments, opened only to the exterior. In this dog Bickel and Sasaki noted, as Pawlow had, that sham feed- ing was attended by a copious flow of gastric juice, a true psychic secretion, resulting from the pleasurable taste of the food. In a typical in- stance the sham feeding lasted five minutes, and the secretion continued for twenty minutes, dur- ing which time 66.7 cubic centimeters of pure gas- tric juice were produced. On another day a cat was brought into the presence of the dog, whereupon the dog flew into a great fury. The cat was soon removed, and the dog pacified. Now the dog was again given the sham feeding for five minutes. In spite of the fact that the animal was hungry and ate eagerly, there was no secretion worthy of men- tion. During a period of twenty minutes, cor- responding to the previous observation, only 9 cubic centimeters of acid fluid were produced, and this was rich in mucus. It is evident that in the dog, as in the boy observed by Bogen, strong emo- tions can so profoundly disarrange the mechanisms of secretion that the pleasurable excitation which accompanies the taking of food cannot cause the normal flow. On another occasion Bickel and Sasaki started gastric secretion in the dog by sham feeding, and 12 BODILY CHANGES when the flow of gastric juice had reached a cer- tain height, the dog was infuriated for five min- utes by the presence of the cat. During the next fifteen minutes there appeared only a few drops of a very mucous secretion. Evidently in this instance a physiological process, started as an accompaniment of a psychic state quietly pleas- urable in character, was almost entirely stopped after another psychic state violent in character. It is noteworthy that in both the favorable and unfavorable results of the emotional excitement illustrated in Bickel and Sasaki's dog the effects persisted long after the removal of the exciting condition. This fact, in its favorable aspect, Bickel 8 was able to confirm in a girl with esophageal and gastric fistulas; the gastric se- cretion long outlasted the period of eating, al- though no food entered the stomach. The in- fluences unfavorable to digestion, however, are stronger than those which promote it. And evidently, if the digestive process, because of emotional disturbance, is for some time inhibited, the swallowing of food which must lie stagnant in the stomach is a most irrational procedure. If a child has experienced an outburst of passion, it is well not to urge the taking of nourishment soon afterwards. Macbeth's advice that "good diges- tion wait on appetite and health on both," is now well-founded physiology. EMOTIONS AND DIGESTION 13 Other digestive glands than the salivary and the gastric may be checked in emotional excite- ment. Kecently Oechsler 9 has reported that in such psychic disturbances as were shown by Bickel and Sasaki to be accompanied by sup- pressed secretion of the gastric juice, the secre- tion of pancreatic juice may be stopped, and the flow of bile definitely checked. All the means of bringing about chemical changes in the food may be thus temporarily abolished. EMOTIONS FAVORABLE AND UNFAVORABLE TO THE CONTRACTIONS OF THE STOMACH AND INTESTINES The secretions of the digestive glands and the chemical changes wrought by them are of little worth unless the food is carried onward through the alimentary canal into fresh regions of diges- tion and is thoroughly exposed to the intestinal wall for absorption. In. studying these mechani- cal aspects of digestion I was led to infer 10 that just as there is a psychic secretion, so like- wise there is probably a "psychic tone" or "psy- chic contraction" of the gastro-intestinal muscles as a result of taking food. For if the vagus nerve supply to the stomach is cut immediately before an animal takes food, the usual contractions of the gastric wall, as seen by the Rontgen rays, do not occur; but if these nerves are cut after food has been eaten with relish, the contractions which 14 BODILY CHANGES have started continue without cessation. The nerves in both conditions were severed under anesthesia, so that no element of pain entered into the experiments. In the absence of hunger, which in itself provides a contracted stomach, 11 the pleasurable taking of food may, therefore, be a primary condition for the appearance of natural contractions of the gastro-intestinal canal. Again just as the secretory activities of the stomach are unfavorably influenced by strong emotions, so also are the movements of the stom- ach; and, indeed, the movements of almost the entire alimentary canal are wholly stopped dur- ing great excitement. In my earliest observa- tions on the movements of the stomach 12 I had difficulty because in some animals the waves of contraction were perfectly evident, while in others there was no sign of activity. Several weeks passed before I discovered that this difference was associated with a difference of sex. In order to be observed with Kontgen rays the animals were restrained in a holder. Although the holder was comfortable, the male cats, particularly the young males, were restive and excited on being fastened to it, and under these circumstances gastric peristaltic waves were absent ; the female cats, especially if elderly, usually submitted with calmness to the restraint, and in them the waves had their normal occurrence. Once a female with EMOTIONS AND DIGESTION 15 kittens turned from her state of quiet content- ment to one of apparent restless anxiety. The movements of the stomach immediately stopped, the gastric wall became wholly relaxed, and only after the animal had been petted and began to purr did the moving waves start again on their course. By covering the cat's mouth and nose with the fingers until a slight distress of breath- ing is produced, the stomach contractions can be stopped at will. In the cat, therefore, any sign of rage or fear, such as was seen in dogs by Lo Conte and by Bickel and Sasaki, was accompanied by a total abolition of the movements of the stomach. Even indications of slight anxiety may be attended by complete absence of the churning waves. In a vigorous young male cat I have watched the stomach for more than an hour by means of the Eontgen rays, and during that time not the slightest beginning of peristaltic activity appeared; yet the only visible indication of ex- citement in the animal was a continued quick twitching of the tail to and fro. What is true of the cat I have found true also of the rabbit, dog and guinea-pig 13 very mild emotional dis- turbances are attended by abolition of peristalsis. The observations on the rabbit have been con- firmed by Auer, 14 who found that the handling of the animal incidental to fastening it gently to a holder stopped gastric peristalsis for a 16 BODILY CHANGES variable length of time. And if the animal was startled for any reason, or struggled excitedly, peristalsis was again abolished. The observa- tions on the dog also have been confirmed; Lom- mel 15 found that small dogs in strange sur- roundings might have no contractions of the stomach for two or three hours. And whenever the animals showed any indications of being un- comfortable or distressed, the contractions were inhibited and the discharge of contents from the stomach checked. Like the peristaltic waves in the stomach, the peristalsis and the kneading movements (seg- mentation) in the small intestine, and the re- versed peristalsis in the large intestine all cease whenever the observed animal shows signs of emotional excitement. There is no doubt that just as the secretory activity of the stomach is affected in a similar fashion in man and in lower animals, so likewise gastric and intestinal peristaltic waves are stopped in man as they are stopped in lower ani- mals, by worry and anxiety and the stronger affective states. The conditions of mental discord may thus give rise to a sense of gastric inertia. For example, a patient described by Miiller 1G testified that anxiety was always accompanied by a feeling of weight, as if the food remained in the stomach. Every addition of food caused an EMOTIONS AND DIGESTION 17 increase of the trouble. Strong emotional states in this instance led almost always to gastric dis- tress, which persisted, according to the grade and the duration of the psychic disturbance, between a half-hour and several days. The patient was not hysterical or neurasthenic, but was a very sensitive woman deeply affected by moods. The feeling of heaviness in the stomach, men- tioned in the foregoing case, is not uncommonly complained of by nervous persons, and may be due to stagnation of the contents. That such stagnation occurs is shown by the following in- stance. A refined and sensitive woman, who had had digestive difficulties, came with her husband to Boston to be examined. They went to a hotel for the night. The next morning the woman ap- peared at the consultant's office an hour after having eaten a test meal. An examination of the gastric contents revealed no free acid, no diges- tion of the test breakfast, and the presence of a considerable amount of the supper of the pre- vious evening. The explanation of this stagna- tion of the food in the stomach came from the family doctor, who reported that the husband had made the visit to the city an occasion for be- coming uncontrollably drunk, and that he had by his escapades given his wife a night of turbu- lent anxiety. The second morning, after the woman had had a good rest, the gastric con- 18 BODILY CHANGES tents were again examined; the proper acidity was found, and the test breakfast had been nor- mally digested and discharged. These cases are merely illustrative and doubt- less can be many times duplicated in the experi- ence of any physician concerned largely with di- gestive disorders. ( Indeed, the opinion has been expressed that a great majority of the cases of gastric indigestion that come for treatment are functional in character and of nervous origin. It is the emotional element that seems most char- acteristic of these cases. To so great an extent is this true that Rosenbach has suggested that as a term to characterize the cause of the distur- bances, "emotional" dyspepsia is better than "nervous" dyspepsia. 17 THE DISTURBING EFFECT OF PAIN ON DIGESTION (^The advocates of the theory of organic evolu- tion early pointed out the similarity between the bodily disturbances in pain and in the major emo- tions. The alterations of function of internal or- gans they could not know about. The general statement, however, that pain evokes the same changes that are evoked by emotion, is true also of these deep-lying structures, j Wertheimer 18 proved many years since that stimulation of a sensory nerve in an anesthetized animal such stimulation as in a conscious animal would in- EMOTIONS AND DIGESTION 19 duce pain quickly abolished the contractions of the stomach. And Netschaiev, working in Paw- low's 19 laboratory, showed that excitation of the sensory fibres in the sciatic nerve for two or three minutes resulted in an inhibition of the secretion of gastric juice that lasted for several hours. Similar effects from painful experience have been not uncommonly noted in human be- ings. 'Mantegazza, 20 in his account of the physi- ology of pain, has cited a number of such ex- amples, and from them he has concluded that pain interferes with digestion by lessening appetite and by producing various forms of dyspepsia, with arrest of gastric digestion, and with vomit- ing and diarrhea. The expression, "sickening pain" is testimony to the power of strong sensory stimulation to upset the digestive processes pro- foundly. Vomiting is as likely to follow violent pain as it is to follow strong emotion. A "sick headache" may be, indeed, a sequence of events in which the pain from the headache is primary, and the nausea and other evidences of digestive disorder are secondary. As the foregoing account has shown, emotional conditions or "feelings" may be accompanied by quite opposite effects in the alimentary canal, some highly favorable to good digestion, some highly disturbing. It is an interesting fact that the feelings having these antagonistic actions are 20 BODILY CHANGES typically expressed through nerve supplies which are correspondingly opposed in their influence on the digestive organs. The antagonism between these nerve supplies is of fundamental impor- tance in understanding not only the operation of conditions favorable or unfavorable to digestion but also in obtaining insight into the conflicts of emotional states. Since a consideration of the arrangement and mode of action of these nerves will establish a firm basis for later analysis and conclusions, they will next be considered. REFERENCES 1 Pawlow : The Work of the Digestive Glands, London, 1902. 2 Bidder and Schmidt : Die Verdauungssaf te und der Stoffwechsel, Leipzig, 1852, p. 35. 3 Richet : Journal de 1' Anatomic et de la Physiologic, 1878, xiv, p. 170. * See Hornborg: Skandinavisches Archiv fur Physiologie, 1904, xv, p. 248. Cade and Latarjet : Journal de Physiologie et Pathologic Generale, 1905, vii, p. 221. Bogen: Archiv fur die gesammte Physiologie, 1907, cxvii, p. 156. Lavenson: Archives of Internal Medicine, 1909, iv, p. 271. 5 Lea : Superstition and Force, Philadelphia, 1892, p. 344. 6 Le Conte: La Cellule, 1900, xvii, p. 291. 7 Bickel and Sasaki : Deutsche medizinische Wochen- schrift, 1905, xxxi, p. 1829. 8 Bickel: Berliner klinische Wochenschrift, 1906, xliii, p. 845. 9 Oechsler: Internationelle Beitrage zur Pathologic und Therapie der Ernahrungstorungen, 1914, v, p. 1. 10 Cannon : The Mechanical Factors of Digestion, London and New York, 1911, p. 200. EMOTIONS AND DIGESTION 21 11 Cannon and Washburn : American Journal of Physi- ology, 1912, xxix, p. 441. 12 Cannon : The American Journal of Physiology, 1898, i, p. 38. 13 Cannon : American Journal of Physiology, 1902, vii, p. xxii. 14 Auer : American Journal of Physiology, 1907, xviii, p. 356. 15 Lommel : Munchener mcdizinische Wochenschrift, 1903, i, p. 1634. 16 Miiller : Deutsches Archiv f ur klinische Medicin, 1907, Ixxxix, p. 434. 17 Rosenbach : Berliner klinische Wochenschrift, 1897, xxxiv, p. 71 18 Wertheimer: Archives de Physiologic, 1892, xxiv, p. 379. 19 Pawlow : Loc. cit., p. 56. 20 Mantegazza : Fisiologia del Dolore, Florence, 1880, p. 123. CHAPTER II THE GENERAL ORGANIZATION OF THE VISCERAL NERVES CONCERNED IN EMOTIONS The structures of the alimentary canal which are brought into activity during the satisfactions of appetite or are checked in their activity during pain and emotional excitement are either the se- creting digestive glands or the smooth muscle which surrounds the canal. Both the gland cells and the smooth-muscle cells differ from other r cells which are subject to nervous influence those of striated, or skeletal, muscle in not being directly under voluntary control and in being slower in their response. The muscle connected with the skeleton responds to stimulation within two or three thousandths of a second; the delay with gland cells and with smooth muscle is more likely to be measured in seconds than in fractions of a second. THE OUTLYING NEURONES The skeletal muscles receive their nerve supply direct from the central nervous system, i. e., the 22 VISCERAL NEEVES 23 nerve fibres distributed to these muscles are parts of neurones whose cell bodies lie within the brain or spinal cord. The glands and smooth muscles of the viscera, on the contrary, are, so far as is now known, never innervated directly from the central nervous system.* The neurones reaching out from the brain or spinal cord never come into immediate relation with the gland or smooth- muscle cells ; there are always interposed between the cerebrospinal neurones and the viscera extra neurones whose bodies and processes lie wholly outside the central nervous system. They are represented in dotted lines in Fig. 1. I have sug- gested that possibly these outlying neurones act as "transformers," modifying the impulses re- ceived from the central source (impulses suited to call forth the quick responses of skeletal muscle), and adapting these impulses to the peculiar, more slowly-acting tissues, the secreting cells and vis- ceral muscle, to which they are distributed. 1 The outlying neurones typically have their cell bodies grouped in ganglia (G's, Fig. 1) which, in the trunk region, lie along either side of the spinal cord and in the head region and in the pelvic part of the abdominal cavity are disposed near the organs which the neurones supply. In some instances these neurones lie wholly within the * The special case of the adrenal glands will be considered later. Tear gland Dilator of pupil Artery of salivary gland Hair Surface artery Sweat gland Heart Hair Surface artery Sweat gland Liver Stomach tf Visceral artery Spleen Intestine Adrenal gland Hair Surface artery Sweat gland Colon Bladder Rectum Artery of external genitals FIGURE 1. Diagram of the more important distributions of the autonomic nervous system. The brain and spinal cord are repre- sented at the left. The nerves to skeletal muscles are not repre- sented. The preganglionic fibres of the autonomic system are in solid lines, the post^anglionic in dash-lines. The nerves of the cranial and sacral divisions are distinguished from those of the thoracico-;lumbar or "sympathetic" division by broader lines. A + mark indicates an augmenting effect on the activity of the organ; a mark, a depressive or inhibitory effect. For further descrip- tion see text. VISCERAL NERVES 25 structure which they innervate (see e. g., the heart and the stomach, Fig. 1). In other instances the fibres passing out from the ganglia the so-called "postganglionic fibres" may traverse long dis- tances before reaching their destination. The in- nervation of blood vessels in the foot by neurones whose cell bodies are in the lower trunk region is an example of this extensive distribution of the fibres. THE THREE DIVISIONS OF THE OUTLYING NEURONES As suggested above, the outlying neurones are connected with the brain and spinal cord by neurones whose cell bodies lie within the central nervous organs. These connecting neurones, rep- resented by continuous lines in Fig. 1, do not pass out in an uninterrupted series all along the cere- bro-spinal axis. Where the nerves pass out from the spinal cord to the fore and hind limbs, fibres are not given off to the ganglia. Thus these con- necting or "proganglionic" fibres are separated into three divisions. In front of the nerve roots for the fore limbs is the head or cranial division ; be- tween the nerve roots for the fore limbs and those for the hind limbs is the trunk division (or thorac- ico-lumbar division, or, in the older terminology, the "sympathetic system"); and after the nerve roots for the hind limbs the sacral division. This system of outlying neurones, with post- 26 BODILY CHANGES ganglionic fibres innervating the viscera, and with preganglionic fibres reaching out to them from the cerebrospinal system, has been called by Langley, to whom we are indebted for most of our knowledge of its organization, the autonomic nervous system. 2 This term indicates that the structures which the system supplies are not sub- ject to voluntary control, but operate to a large degree independently. As we have seen, a highly potent mode of influencing these structures is through conditions of pain and emotional excite- ment. The parts of the autonomic system the cranial, the sympathetic, and the sacral have a number of peculiarities which are of prime im- portance in accounting for the bodily manifesta- tions of such affective states. THE EXTENSIVE DISTRIBUTION OF NEURONES OF THE "SYMPA- THETIC" DIVISION AND THEIR ARRANGEMENT FOR DIFFUSE ACTION The fibres of the sympathetic division differ from those of the other two divisions in being distributed through the body very widely. They go to the eyes, causing dilation of the pupils. They go to the heart and, when stimulated, they cause it to beat rapidly. They carry impulses to arteries and arterioles of the skin, the abdominal viscera, and other parts, keeping the smooth mus- cles of the vessel walls in a state of slight con- VISCERAL NERVES 27 traction or tone, and thus serving to maintain an arterial pressure sufficiently high to meet sud- den demands in any special region; or, in times of special discharge of impulses, to increase the tone and thus also the arterial pressure. They are distributed extensively to the smooth muscle attached to the hairs; and when they cause this muscle to contract, the hairs are erected. They go to sweat glands, causing the outpouring of sweat. These fibres pass also to the entire length of the gastro-intestinal canal. And the inhibi- tion of digestive activity which, as we have learned, occurs in pain and emotional states, is due to impulses which are conducted outward by the splanchnic nerves the preganglionic fibres that reach to the great ganglia in the upper abdo- men (see Fig. 1) and thence are spread by post- ganglionic fibres all along the gut. 3 They in- nervate likewise the genito-urinary tracts, causing contraction of the smooth muscle of the internal genital organs, and usually relaxation of the blad- der. Finally they affect the liver, releasing the storage of material there in a manner which may be of great service to the body in time of need. The extensiveness of the distribution of the fibres of the sympathetic division is one of its most prominent characteristics. Another typical feature of the sympathetic di- vision is an arrangement of neurones for diffuse 28 BODILY CHANGES discharge of the nerve impulses. As shown dia- grammatically in Fig. 1, the preganglionic fibres from the central nervous system may extend through several of the sympathetic ganglia and give off in each of them connections to cell bodies of the outlying neurones. Although the neurones which transmit sensory impulses from the skin into spinal cord have similar relations to nerve cells lying at different levels of the cord, the op- eration in the two cases is quite different. In the spinal cord the sensory impulse produces di- rected and closely limited effects, as, for example, when reflexes are being evoked in a "spinal" ani- mal (i. e., an animal with the spinal cord isolated from the rest of the central nervous system), the left hind limb is nicely lifted, in response to a harmful stimulus applied to the left foot, without widespread marked involvement of the rest of the body in the response. 4 In the action of the sympathetic division, on the contrary, the con- nection of single preganglionic fibres with nu- merous outlying neurones seems to be not at all arranged for specific effects in this or that par- ticular region. There are, to be sure, in different circumstances variations in the degree of ac- tivity of different parts; for example, it is prob- able that dilation of the pupil in the cat occurs more readily than erection of the hairs. It may be in this instance, however, that specially direct VISCERAL NEKVES 29 pathways to the eye are present for common use in non-emotional states (in dim light, e. g.), and that only slight general disturbance in the central nervous system, therefore, would be necessary to send impulses by these well-worn courses. Thus for local reasons (dust, e. g.) tears might flow from excitation of the tear glands by sympathetic impulses, although other parts innervated by this same division might be but little disturbed. AVe have no means of voluntarily wearing these path- ways, however, and both from anatomical and physiological evidence the neurone relations in the sympathetic division of the autonomic system seem devised for widespread diffusion of nervous impulses. THE ARRANGEMENT OF NEURONES OF THE CRANIAL AND SACRAL DIVISIONS FOR SPECIFIC ACTION The cranial and sacral autonomic divisions differ from the sympathetic in having only re- stricted distribution (see Fig. 1). The third cran- ial nerves deliver impulses from the brain to ganglia in which lie the cell bodies of neurones innervating smooth muscle only in the front of the eyes. The vagus nerves are distributed to the lungs, heart, stomach, and small intestine. As shown diagrammatically in Fig. 1, the out- lying neurones in the last three of these organs lie within the organs themselves. By this ar- rangement, although the preganglionic fibres of 30 BODILY CHANGES the vagi are extended in various directions to structures of quite diverse functions, singleness and separateness of connection of the peripheral organs with the central nervous system is as- sured. The same specific relation between effer- ent fibres and the viscera is seen in the sacral autonomic. In this division the preganglionic fibres pass out from the spinal cord to ganglia lying in close proximity to the distal colon, the bladder, and the external genitals. And the post- ganglionic fibres deliver the nerve impulses only to the nearby organs. Besides these innervations the cranial and sacral divisions supply individual arteries with "dilator nerves" nerves causing relaxation of the particular vessels. Quite typi- cally, therefore, the efferent fibres of the two terminal divisions of the autonomic differ from those of the mid-division in having few of the diffuse connections characteristic of the mid- division, and in innervating distinctively the or- gans to which they are distributed. The cranial and sacral preganglionic fibres resemble thus the nerves to skeletal muscles, and their arrangement provides similar possibilities of specific and sepa- rate action in any part, without action in other parts. THE CRANIAL DIVISION A CONSERVER OP BODILY KESOURCES The cranial autonomic, represented by the vagus nerves, is the part of the visceral nervous VISCERAL NERVES 31 system concerned in the psychic secretion of the gastric juice. Pawlow showed that when these nerves are severed psychic secretion is abolished. The cranial nerves to the salivary glands are sim- ilarly the agents for psychic secretion in these organs, and are known to cause also dilation of the arteries supplying the glands, so that during ac- tivity the glands receive a more abundant flow of blood. As previously stated (see p. 13), the evi- dence for a psychic tonus of the gastro-intestinal musculature rests on a failure of the normal con- tractions if the vagi are severed before food is taken, in contrast to the continuance of the con- tractions if the nerves are severed just after- wards. The vagi artificially excited are well- known as stimulators of increased tone in the smooth muscle of the alimentary canal. Aside from these positive effects on the muscles of the digestive tract and its accessory glands, cranial autonomic fibres cause contraction of the pupil of the eye, and slowing of the heart rate. A glance at these various functions of the cra- nial division reveals at once that they serve for bodily conservation. By narrowing the pupil of the eye they shield the retina from excessive light. By slowing the heart rate, they give the cardiac muscle longer periods for rest and in- vigoration. And by providing for the flow of saliva and gastric juice and by supplying the mus- 32 BODILY CHANGES cular tone necessary for contraction of the ali- mentary canal, they prove fundamentally essen- tial to the processes of proper digestion and absorption by which energy-yielding material is taken into the body and stored. To the cranial division of the- visceral nerves, therefore, belongs the quiet service of building up reserves and forti- fying the body against times of need or stress. THE SACRAL DIVISION A GROUP OF MECHANISMS FOR EMPTYING Sacral autonomic fibres cause contraction of the rectum and distal colon and also contraction of the bladder. In both instances the effects result reflexly from stretching of the tonically con- tracted viscera by their accumulating contents. No affective states precede this normal action of the sacral division and even those which accom- pany or follow are only mildly positive ; a feeling of relief rather than of elation usually attends the completion of the act of defecation or mic- turition though there is testimony to the con- trary. The sacral autonomic fibres also include, how- ever, the nervi erigentes which bring about en- gorgement of erectile tissue in the external geni- tals. According to Langley and Anderson 5 the sacral nerves have no effect on the internal gen- erative organs. The vasa deferentia and the seminal vesicles whose rhythmic contractions VISCERAL NERVES 33 mark the acme of sexual excitement in the male, and the uterus whose contractions in the female are probably analogous, are supplied only by lumbar branches part of the sympathetic divi- sion. These branches also act in opposition to the nervi erigentes and cause constriction of the blood vessels of the external genitals. The sexual orgasm involves a high degree of emotional ex- citement; but it can be rightly considered as es- sentially a reflex mechanism; and, again in this instance, distention of tubules, vesicles, and blood vessels can be found at the beginning of the in- cident, and relief from this distension at the end. Although distention is the commonest occasion for bringing the sacral division into activity it is not the only occasion. Great emotion, such as is accompanied by nervous discharges via the sym- pathetic division, may also be accompanied by dis- charges via the sacral fibres. The involuntary voiding of the bladder and lower gut at times of violent mental stress is well-known. Veterans of wars testify that just before the beginning of a battle many of the men have to retire temporarily from the firing line. And the power of sights and smells and libidinous thoughts to disturb the regions controlled by the nervi erigentes proves that this part of the autonomic system also has its peculiar affective states. The fact that one part of the sacral division, e. g., the distribu- 34 BODILY CHANGES tion to the bladder, may be in abeyance, while another part, e. g., the distribution to the rectum, is active, illustrates again the directive discharge of impulses which has been previously described as characteristic of the cranial and sacral portions of the autonomic system. Like the cranial division, the sacral is engaged in internal service to the body, in the performance of acts leading immediately to greater comfort. THE SYMPATHETIC DIVISION ANTAGONISTIC TO BOTH THE CRANIAL AND THE SACRAL As indicated in the foregoing description many of the viscera are innervated both by the cranial or sacral part of the autonomic and by the sym- pathetic. When the mid-part meets either end- part in any viscus their effects are antagonistic. Thus the cranial supply to the eye contracts the pupil, the sympathetic dilates it; the cranial slows the heart, the sympathetic accelerates it; the sacral contracts the lower part of the large intestine, the sympathetic relaxes it; the sacral relaxes the exit from the bladder, the sym- pathetic contracts it. These opposed effects are indicated in Fig. 1 by 4- for contraction, ac- celeration or increased tone ; and by - for inhibi- tion, relaxation, or decreased tone.* * The vagus nerve, when artificially stimulated, has a pri- mary, brief inhibitory effect on the stomach and small intes- tine ; its main function, however, as already stated, is to pro- VISCERAL NERVES 35 Sherrington has demonstrated that the setting of skeletal muscles in opposed groups about a joint or system of joints as in flexors and ex- tensors is associated with an internal organiza- tion of the central nervous system that provides for relaxation of one group of the opposed mus- cles when the other group is made to contract. This "reciprocal innervation of antagonistic mus- cles," as Sherrington has called it, 6 is thus a device for orderly action in the body. As the above description has shown, there are peripheral oppositions in the viscera corresponding to the oppositions between flexor and extensor muscles. In all probability these opposed innervations of the viscera have counterparts in the organization of neurones in the central nervous system. Sher- rington has noticed, and I can confirm the obser- vation, that even though the sympathetic supply to the eye is severed and is therefore incapable of causing dilation of the pupil, nevertheless the pupil dilates in a paroxysm of anger due, no doubt (because the response is too rapid to be mediated by the blood stream), to central inhibi- tion of the cranial nerve supply to the constrictor muscles i. e., an inhibition of the muscles which naturally oppose the dilator action of the sym- pathetic. Pain, the major emotions fear and duce increased tone and contraction in these organs. This double action of the vagus is marked thus, T , in Fig. 1. 36 BODILY CHANGES rage and also intense excitement, are manifested in the activities of the sympathetic division. When in these states impulses rush out over the neurones of this division they produce all the changes typical of sympathetic excitation, such as dilating the pupils, inhibiting digestion, caus- ing pallor, accelerating the heart, and various other well-known effects. The impulses of the sympathetic neurones, as indicated by their domi- nance over the digestive process, are capable of readily overwhelming the conditions established by neurones of the cranial division of the auto- nomic system. NEURONES OF THE SYMPATHETIC DIVISION AND ADRENAL SECRETION HAVE THE SAME ACTION Lying anterior to each kidney is a small body the adrenal gland. It is composed of an external portion or cortex, and a central portion or me- dulla. From the medulla can be extracted a sub- stance, called variously suprarenin, adrenin, epi- nephrin or "adrenalin,"* which, in extraordinarily minute amounts, affects the structures innervated by the sympathetic division of the autonomic sys- * The name "adrenalin" is proprietary. "Epinephrin" and "adrenin" have been suggested as terms free from commer- cial suggestions. As adrenin is shorter and more clearly related to the common adjectival form, adrenal, I have fol- lowed Schafer in using adrenin to designate the substanoe produced physiologically by the adrenal glands. VISCERAL NERVES 37 tern precisely as if they were receiving nervous impulses. For example, when adrenin is injected into the blood, it will cause pupils to dilate, hairs to stand erect, blood vessels to be constricted, the activities of the alimentary canal to be inhibited, and sugar to be liberated from the liver. These effects are not produced by action of the substance on the central nervous system, but by direct ac- tion on the organ itself. 7 And the effects oc- cur even after the structures have been removed from the body and kept alive artificially. The adrenals are glands of internal secretion, i. e., like the thyroid, parathyroid, and pituitary glands, for example ; they have no connection with the surface of the body, and they give out into the blood the material which they elaborate. The blood is carried away from each of them by the lumbo-adrenal vein which empties either into the renal vein or directly into the inferior vena cava just anterior to the openings of the renal veins. The adrenal glands are supplied by preganglionic fibres of the autonomic group, 8 shown in solid line in Fig. 1. This seems an exception to the general rule that gland cells have an outlying neurone between them and the neurones of the central nervous system. The medulla of the adre- nal gland, however, is composed of modified nerve cells, and may therefore be regarded as offering exceptional conditions. 38 BODILY CHANGES The foregoing brief sketch of the organization of the autonomic system brings out a number of points that should be of importance as bearing on the nature of the emotions which manifest themselves in the operations of this system. Thus it is highly probable that the sympathetic division, because arranged for diffuse discharge, is likely to be brought into activity as a whole, whereas the sacral and cranial divisions, arranged for particular action on separate organs, may operate in parts. Also, because antagonisms exist be- tween the middle and either end division of the autonomic, affective states may be classified ac- cording to their expression in the middle or an end division and these states would be, like the nerves, antagonistic in character. And finally, since the adrenal glands are innervated by au- tonomic fibres of the mid-division, and since ad- renal secretion stimulates the 'same activities that are stimulated nervously by this division, it is possible that disturbances in the realm of the sympathetic, although initiated by nervous dis- charge, are automatically augmented and pro- longed through chemical effects of the adrenal secretion. REFERENCES 1 Cannon : The American Journal of Psychology, 1914, xxv, p. 257. VISCERAL NERVES 39 2 For a summary of his studies of the organization of the autonomic system, see Langley: Ergebnisse der Physiologic, Wiesbaden, 1903, ii 2 , p. 818. 3 See Cannon : American Journal of Physiology, 1905, xiii, p. xxii. 4 See Sherrington : The Integrative Action of the Nerv- ous System, New York, 1909, p. 19. 5 Langley and Anderson : Journal of Physiology, 1895, xix, see pp. 85, 122. 6 Sherrington : Loc. cit., p. 90. 7 Elliott: Journal of Physiology, 1905, xxxii, p. 426. 8 See Elliott: Journal of Physiology, 1913, xlvi, p. 289 ff. CHAPTER III METHODS OF DEMONSTRATING ADEENAL SECRETION AND ITS NERVOUS CONTROL As stated in the first chapter, the inhibition of gastric secretion produced by great excitement long outlasts the presence of the object which evokes the excitement. The dog that was en- raged by seeing a cat for five minutes secreted only a few drops of gastric juice during the next fifteen minutes. Why did the state of excitation persist so long after the period of stimulation had ended? This question, which presented itself to me while reading Bickel and Sasaki's paper, fur- nished the suggestion expressed at the close of the last chapter, that the excitement might pro- voke a flow of adrenal secretion, and that the changes originally induced in the digestive organs by nervous impulses might be continued by circu- lating adrenin. The prolongation of the effect might be thus explained. Whether that idea is correct or not has not been tested. Its chief serv- ice was in leading to an enquiry as to whether 40 ADRENAL SECRETION 41 the adrenal glands are in fact stimulated to action in emotional excitement. The preganglionic fibres passing to the glands are contained in the splanch- nic nerves. What is the effect of splanchnic stim- ulation? THE EVIDENCE THAT SPLANCHNIC STIMULATION INDUCES ADRENAL SECRETION It was in 1891 that Jacobi l described nerve fibres derived from the splanchnic trunks which were distributed to the adrenal glands. Six years later Biedl 2 found that these nerves conveyed vaso-dilator impulses to the glands, and he sug- gested that they probably conveyed also secre- tory impulses. Evidence in support of this sug- gestion was presented the following year by Dreyer, 3 who demonstrated that electrical ex- citation of the splanchnic nerves produced in the blood taken from the adrenal veins an increased amount of a substance having the power of rais- ing arterial blood pressure, and that this result was independent of accompanying changes in the blood supply to the glands. The conclusion drawn by Dreyer that this substance was adrenin has been confirmed in various ways by later observers. Tscheboksaroff 4 repeated Dreyer' s procedure and found in blood taken from the veins after splanchnic stimulation evidences of the presence of adrenin that were previously absent. Asher 5 42 BODILY CHANGES observed a rise of blood pressure when the glands were stimulated in such a manner as not to cause constriction of the arteries the rise was there- fore assumed to be due to secreted adrenin. Dilation of the pupil was used by Meltzer and Joseph 6 to prove secretory action of the splanch- nics on the adrenal glands ; they found that stim- ulation of the distal portion of the cut splanchnic nerve caused the pupil to enlarge an eff ect char- acteristic of adrenin circulating in the blood. Elliott 7 repeated this procedure, but made it a more rigorous proof of internal secretion of the adrenals by noting that the effect failed to ap- pear if the gland on the stimulated side was re- moved. Additional proof was brought by myself and Lyman 8 when we found that the typical drop in arterial pressure produced in cats by in- jecting small amounts of adrenin could be ex- actly reproduced by stimulating the splanchnic nerves after the abdominal blood vessels, which contract when these nerves are excited, were tied so that no changes in them could occur to in- fluence the rest of the circulation. The problem of splanchnic influence on the ad- renal glands Elliott attacked by a still different method. Using, as a measure, the graded effects of graded amounts of adrenin on blood pressure, he was able to assay the quantity of adrenin in adrenal glands after various conditions had been ADKENAL SECEETION 43 allowed to prevail. The tests were made on cats. In these animals each adrenal gland is supplied only by the splanchnic fibres of its own side, and the two glands normally contain almost exactly the same amount of adrenin. Elliott 9 found that when the gland on one side was isolated by cutting its splanchnic supply, and then impulses were sent along the intact nerves of the other side, either by disturbing the animal or by artificial excita- tion of the nerves, the gland to which these fibres reached invariably contained less adrenin, often very much less, than the isolated gland. Kesults obtained by the method employed by Elliott have been confirmed with remarkable exactness in re- sults obtained by Folin, Denis and myself, 10 using a highly sensitive color test after adding the gland extract to a solution of phosphotungstic acid. All these observations, with a variety of meth- ods, and by a respectable number of reliable in- vestigators, are harmonious in bringing proof that artificial stimulation of the nerves leading to the adrenal glands will induce secretory ac- tivity in the adrenal medulla, and that in conse- quence adrenin will be increased in the blood. The fact is therefore securely established that in the body a mechanism exists by which these glands can be made to discharge this peculiar sub- stance promptly into the circulation. 44 BODILY CHANGES THE QUESTION OF ADRENAL SECRETION IN EMOTIONAL EXCITEMENT As we have already seen, the phenomena of a great emotional disturbance in an animal indi- cate that sympathetic impulses dominate the vis- cera. When, for example, a cat becomes fright- ened, the pupils dilate, the activities of the stomach and intestines are inhibited, the heart beats rapidly, the hairs of the back and tail stand erect from one end of the animal to the other there are abundant signs of nervous discharges along sympathetic courses. Do not the adrenal glands share in this widespread subjugation of the viscera to sympathetic control? This question, whether the common excitements of an animal's life might be capable of evoking a discharge of adrenin, was taken up by D. de la Paz and myself in 1910. We made use of the nat- ural enmity between two laboratory animals, the dog and the cat, to pursue pur experiments. In these experiments the cat, fastened in a comfor- table holder (the holder already mentioned as be- ing used in X-ray studies of the movements of the alimentary canal), was placed near a barking dog. Some cats when thus treated showed al- most no signs of fear; others, with scarcely a movement of defence, presented the typical pic- ture. In favorable cases the excitement was al- lowed to prevail for five or ten minutes, and in ADRENAL SECRETION 45 a few cases longer. Samples of blood were taken within a few minutes before and after the period. THE METHOD OF SECURING BLOOD FROM NEAR THE ADRENAL VEINS The blood was obtained from the inferior vena cava anterior to the opening of the adrenal veins, i. e., at a point inside the body near the level of the notch at the lower end of the sternum. To get the blood so far from the surface without disturbing the animal was at first a difficult prob- lem. We found, however, that by making anes- thetic with ethyl chloride the skin directly over the femoral vein high in the groin, the vein could be quickly bared, cleared of connective tissue, tied, and opened, without causing any general dis- turbance whatever. A long, fine, flexible catheter (2.4 millimeters in diameter) which had pre- viously been coated with vaseline inside and out, to lubricate it and to delay the clotting of blood within it, was now introduced into the opening in the femoral vein, thence through the iliac and on into the inferior cava to a point near the level of the sternal notch. A thread tied around this tube where, after being inserted to the proper dis- tance, it disappeared into the femoral vein, marked the extent of insertion, and permitted a later introduction to the same extent. This slight operation a venesection, commonly practised on 46 BODILY CHANGES onr ancestors consumed only a few minutes, and as the only possibility of causing pain was guarded against by local anesthesia, the animal remained tranquil throughout. Occasionally it was necessary to stroke the cat's head gently to keep her quiet on the holder, and under such cir- cumstances I have known her to purr during all the preparations for obtaining the blood, and while the blood was being taken. The blood (3 or 4 cubic centimetres) was slowly drawn through the catheter into a clean glass syringe. Care was taken to avoid any marked suction such as might cause collapse of the vein near the inner opening of the tube. As soon as the blood was secured, the catheter was removed and the vein tied loosely, to prevent bleeding. The blood was at once emptied into a beaker, and the fibrin whipped from it by means of fringed rubber tubing fitted over a glass rod. Since this defibrinated blood was obtained while the ani- mal was undisturbed, it was labelled "quiet blood." The animal was then exposed to the barking dog, as already described, and immediately there- after blood was again removed, from precisely the same region as before. This sample, after being defibrinated, was labelled "excited blood." The two samples, the "quiet" and the "excited," both obtained in the same manner and subse- ADRENAL SECRETION 47 quently treated in the same manner, were now tested for their content of adrenin. THE METHOD OF TESTING THE BLOOD FOR ADRENIN It was desirable to use as a test tissues to which the blood was naturally related. As will be recalled, adrenin affects viscera even after they have been removed from the body, just as if they were receiving impulses via sympathetic fibres, and further, that sympathetic fibres nor- mally deliver impulses which cause contraction of the internal genitals and relaxation of the stomach and intestines. The uterus has long been employed as a test for adrenin, the presence of which it indicates by increased contraction. That isolated strips of the longitudinal muscle of the intestine, which are contracting rhythmically, are characteristically inhibited by adrenin in dilu- tions of 1 part in 20 millions, had been shown by Magnus in 1905. Although, previous to our in- vestigation in 1910, this extremely delicate reac- tion had not been used as a biological signal for adrenin, it possesses noteworthy advantages over other methods. The intestine is found in all ani- mals and not in only half of them, as is the uterus ; it is ready for the test within a few minutes, in- stead of the several hours said to be required for the best use of the uterus preparation; 11 and it responds by relaxing. This last characteristic 48 BODILY CHANGES is especially important, for in deflbrinated blood there are, besides adrenin, other substances cap- able of causing contraction of smooth muscle, 12 and liable therefore to lead to erroneous con- clusions when a structure which responds by con- tracting, such as uterus or artery, is used to prove whether adrenin is present. On the other hand, substances producing relaxation of smooth muscle are few, and are unusual in blood. 13 We used, therefore, the strip of intestinal mus- cle as an indicator. Later Hoskins 14 modified our procedure by taking, instead of the strip, a short segment of the rabbit intestine. The seg- ment is not subjected to danger of injury during its preparation, and when fresh it is almost in- credibly sensitive. It may be noticeably inhibited by adrenin, 1 part in 200 millions ! The strip, or the intestinal segment, was sus- pended between minute wire pincers (serrcs fines) in a cylindrical chamber 8 millimeters in diameter and 5 centimeters deep. By a thread attached to the lower serre fine the preparation was drawn into the chamber, and was held firmly; by the upper one it was attached to the short end of a writing lever (see Fig. 2). When not ex- posed to blood, the strip was immersed in a nor- mal solution of the blood salts (Singer's). The blood or the salt solution could be quickly with- drawn from or introduced into the chamber, with- ADRENAL SECRETION 49 out disturbing the muscle, by means of a fine pipette passed down along the inner surface. The chamber and its contents, the stock of Ringer's FIGURE 2. Diagram of the arrangements for recording con- tractions of the intestinal muscle. solution, and the samples of "quiet" and "ex- cited" blood were all surrounded by a large vol- ume of water kept approximately at body tem- perature (37 C.). Through the blood or the salt solution in the chamber oxygen was passed in a slow but steady stream of bubbles. Under these circumstances the strip will live for hours, and will contract and relax in a beautifully regular rhythm, which may be recorded graphically by the writing lover. The first effect of surrounding the muscle with blood, whether "quiet" or "excited," was to send it into a strong contraction which might persist, sometimes with slight oscillations, for a minute or two (see Figs. 4 and 5), After the initial short- ening, the strip, if in quiet blood soon began to 50 BODILY CHANGES contract and relax rhythmically and with each re- laxation to lengthen more, until a fairly even base line appeared in the written record. At this stage the addition of fresh "quiet" blood usually had no effect, even though the strip were washed once with Einger's solution before the second por- tion of the blood was added. For comparison of the effects of "quiet" and "excited" blood on the contracting strip, the two samples were each added to the muscle immediately after the Ring- er's solution had been removed, or they were ap- plied to the muscle alternately and the differences in effect then noted. The results obtained by these methods are next to be presented. REFERENCES 1 Jacobi : Archiv f iir experimentelle Pathologic und Phar- makologie, 1891, xxix, p. 185. 2 Biedl : Archiv f iir die gesammte Physiologic, 1897, Ixvii, pp. 456, 481. 8 Dreyer : American Journal of Physiology, 1898-99, ii, p. 219. 4 Tscheboksarof? : Archiv f iir die gesammte Physiologic, 1910, cxxxvii, p. 103. 5 Asher : Zcitschrif t f iir Biologic, 1912, Iviii, p. 274. 6 Meltzer and Joseph : American Journal of Physiology, 1912, xxix, p. xxxiv. 7 Elliott: Journal of Physiology, 1912, xliv, p. 400. 8 Cannon and Lyman : American Journal of Physiology, 1913, xxxi, p. 377. 9 Elliott : Journal of Physiology, 1912, xliv, p. 400. 10 Folin, Cannon and Denis : Journal of Biological Chem- istry, 1913, xiii, p. 477. ADRENAL SECRETION 51 11 Fraenkel : Archiv f iir experimentelle Pathologie und Pharmakologie, 1909, Ix, p. 399. 12 See O'Connor : Archiv f iir die experimentelle Patholo- gie und Pharmakologie, 1912, Ixvii, p. 206. 13 Grutzner: Ergebnisse der Physiologic, 1904, iii 2 , p. 66; Magnus : Loc. cit., p. 69. 14 IIoskins: Journal of Pharmacology and Experimental Therapeutics, 1911, iii, p. 95. CHAPTER IV ADKENAL SECKETION IN STRONG EMOTIONS AND PAIN If the secretion of adrenin is increased in strong emotional states and in pain, that constitutes a fact of considerable significance, for, as already mentioned, adrenin is capable of producing many of the bodily changes which are characteristically manifested in emotional and painful experiences. It is a matter of prime importance for further discussion to determine whether the adrenal glands are in fact roused to special activity in times of stress. THE EVIDENCE THAT ADRENAL SECRETION Is INCREASED IN EMOTIONAL EXCITEMENT That blood from the adrenal veins causes the relaxation of intestinal muscle characteristic of adrenal extract or adrenin is shown in Fig. 3. The muscle was originally beating in blood which contained no demonstrable amount of adrenal se- cretion ; this inactive blood was replaced by blood 52 ADEENAL SECRETION IN EMOTIONS 53 from the adrenal veins, obtained after quick etherization. Etherization, it will be recalled, is accompanied by a "stage of excitement." Re- laxation occurred almost immediately (at b), Then the rhythm was renewed in the former FIGURE 3. Intestinal muscle beat- ing in inactive blood, which was with- drawn from the chamber at a. Blood from the adrenal vein of an animal ex- cited by etherization was substituted at 6, and withdrawn at c. Contrac- tions were restored in the original in- active blood which was removed at d. Blood from the renal vein (same ani- inal) was added at e. In this and subsequent records time is marked in half minutes. blood, and thereupon the muscle was surrounded with blood from the vein leading away from the left kidney, i. e., blood obtained from the same animal and under the same conditions as the adrenal blood, but from a neighboring vein. No relaxation occurred. l>y this and other similar tests tlie reliability of the method was proved. 54 BODILY CHANGES In no instance did blood from the inferior vena cava of the quiet normal animal produce relaxa- tion. On the other hand, blood from the animal after emotional excitement showed more or less promptly the typical relaxation. In Fig. 4 is FIGURE 4. Alternate application of " excited " blood (at 6 and/) and "quiet" blood (at d), from the same animal, to in- testinal muscle initially beating in Ringer's solution. represented the record of intestinal muscle which was beating regularly in Einger's solution. At a the Einger's solution was removed, and at & "ex- cited" blood was added; after the preliminary shortening, which, as already stated, occurs at the first immersion in blood, the muscle length- ened gradually into complete inhibition. At c the "excited" blood was removed, and at d "quiet" blood was added in its place. The muscle at once began fairly regular rhythmic beats. At e the "quiet" blood was removed, and at / the "excited" blood was again applied. The muscle lengthened almost immediately into an inhibited state. In this instance the "excited" blood was taken after ADEENAL SECRETION IN EMOTIONS 55 the cat had been barked at for about fifteen min- utes. The increase of effect with prolongation of the period of excitement is shown in Fig. 5. A is the FIGURE 5. The effect of prolonging the excitement. A. the record in " quiet" serum; B, in defibrinated blood after eleven minutes of excitement; and C, in serum after fifteen minutes of excitement. record of contractions after the muscle was sur- rounded with "quiet" blood serum. B shows the gradual inhibition which occurred when the mus- cle was surrounded with defibrinated blood taken when the animal had been excited eleven minutes. And C is the record of rapid inhibition after fif- teen minutes of excitement. In other instances the effect was manifested merely by a lowering of the tonus of the muscle, and a notable slowing of the beats, without, however, a total abolition of them. The inference that this inhibition of contrac- tion of the intestinal muscle is due to an increased amount of adrenal secretion in the "excited" 56 BODILY CHANGES blood de la Paz and I justified on several grounds : (1) The inhibition was produced by "excited" blood from the inferior vena cava anterior to the mouths of the adrenal veins, when blood from the femoral vein, taken at the same time, had no in- hibitory influence. Since blood from the femoral vein is typical of the cava blood below the en- trance of the kidney veins, the conclusion is war- ranted that the difference of effect of the two samples of blood is not due to any agent below the kidneys. But that blood from the kidneys does not cause the relaxation is shown in Fig. 3. FIGURE 6. Failure of the cava blood (added at a) to produce inhibition when excitement has occurred after removal of the adrenal glands. The inn^-le later proved sensitive to adrenm in blood in the ratio 1:1,000,000. The only other structures which could alter the blood between the two points at which it was taken are the adrenal glands, and the material ADEENAL SECEETION IN EMOTIONS 57 secreted by them would produce precisely the inhibition of contraction which was in fact pro- duced. (2) If in ether anesthesia the blood vessels leading to and from the adrenal glands are first carefully tied, and then the glands are removed, ex- FIGURE 7. Effect of adding adrenin 1:1,000,000 (A), 1:2,000,000 (B), and 1:3,000,000 (C), to formerly inactive blood. In each case a marks the moment when the quiet blood was removed, and 6, the time when the blood with adrenin was added. citement four or five hours later, before the weak- ness that follows the removal has become promi- nent, does not alter the blood so that the typical inhibition occurs (see Fig. 6). Thus, although the animal shows all the characteristic signs of sympathetic stimulation, the blood, in the absence of the adrenals, remains unchanged. (3) As already shown, sometimes the effect pro- 58 BODILY CHANGES duced by the "excited" blood was prompt inhibi- tion, sometimes the inhibition followed only after several beats, and sometimes a slowing and short- ening of contractions, with a lower tone, were the sole signs of the action of adrenin. All these degrees of relaxation can be duplicated by adding to inactive blood varying amounts of adrenin. Fig. 7 shows the effects, on a somewhat insensi- tive muscle preparation, of adding adrenin, 1:1,000,000 (A), 1:2,000,000 (B), and 1:3,000,000 (C), to different samples of blood previously with- out inhibitory influence. These effects of adrenin and the effects produced by blood taken near the opening of the adrenal veins are strikingly analo- gous. (4) Emden and v. Furth 1 have reported that 0.1 gram of suprarenin chloride disappears almost completely in two hours if added to 200 cubic centimeters of defibrinated beef blood, and the mixture constantly aerated at body temperature. "Excited" blood which produces inhibition loses that power on standing in the cold for twenty-four hours, or on being kept warm and agitated with bubbling oxygen. This change is illustrated in Fig. 8 ; the power of the "excited" blood to inhibit the contractions of the intestinal muscle when rec- ord A was written was destroyed after three hours of exposure to bubbling oxygen, as shown by record B. The destruction of adrenin and ADRENAL SECRETION IN EMOTIONS 59 the disappearance of tlie effect which adrenin would produce are thus closely parallel. All these considerations, taken with the proof FIGURE 8. The effect of bubbling oxygen through active blood. A, re- laxation after active blood applied at a; B, failure of relaxation when the same blood, oxygenated three hours, was applied to a fresh strip at b, that sympathetic impulses increase secretion of the adrenal glands, and taken also with the evidence that, during such emotional excitement as was em- ployed in these experiments, signs of sympathetic discharges appeared throughout the animal from the dilated pupil of the eye to the standing hairs of the tail-tip, led us to the conclusions that the characteristic action of adrenin on intestinal mus- cle was in fact, in our experiments, due to secre- tion of the adrenal glands, and that that secretion is increased in great emotion. THE EVIDENCE THAT ADRENAL SECRETION is INCREASED BY "PAINFUL" STIMULATION As mentioned in the first chapter, stimulation of sensory fibres in one of the larger nerve trunks 60 BODILY CHANGES is known to result in such, nervous discharges along sympathetic paths as to produce marked inhibi- tion of digestive processes. Other manifestations of sympathetic innervations e. g., contraction of arterioles, dilation of pupils, erection of hairs are also demonstrable. And since the adrenal glands are stimulated to activity by sympathetic impulses, it was possible that they would be af- fected as are other structures supplied with sym- pathetic fibres, arid that they would secrete in greater abundance when sensory nerves were irri- tated. The testing of this possibility was undertaken by Hoskins and myself in 1911. Since bodily changes from "painful" stimulation can in large degree be produced in an anesthetized animal, without, how- ever, an experience of pain by the animal, it was possible to make the test quite simply. The sen- sory stimulus was a rapidly interrupted induced current applied to the sciatic nerve. The current was increased in strength as time passed, and thus the intensity of the effect, indicated by continuous dilation of the pupils, was maintained. There was no doubt that such stimulation would have caused very severe pain if the animal had not been anes- thetized. Indeed, the stimulus used was probably much stronger than would be necessary to obtain a positive result in the absence of the anesthetic (urethane), which markedly lessens the irritabil- ADRENAL SECRETION IN EMOTIONS 61 ity of visceral nerve fibres. 2 In different in- stances the stimulation lasted from three to six minutes. Throughout the period there was mark- edly increased rapidity and depth of breathing. As Fig. 9 shows, the normal blood, removed FIGURE 9. Intestinal mus- cle beating in normal vena cava blood, removed at 1 and re- newed at 2. At 3 normal blood removed. At 4 contraction in- hibited by vena cava blood drawn after sensory stimula- tion; at 5 removed. At 6 Rin- trpr's solution auhstitutpd. 62 BODILY CHANGES from the vena cava before stimulation, caused no inhibition of the beating segment, whereas that removed afterwards produced a deep relaxation. Hoskins and I showed that the increased respira- tion which accompanies "painful" stimulation does not augment adrenal activity. We concluded, therefore, that when a sensory trunk is strongly excited the adrenal glands are reflexly stimulated, and that they pour into the blood stream an in- creased amount of adrenin. CONFIRMATION OF OUR RESULTS BY OTHER OBSERVERS The foregoing experiments and conclusions were reported in 1911. In 1912. Anrep 3 found that a denervated limb at first expands but later quickly contracts on sensory stimulation. The phase of contraction disappeared if the adrenal glands were removed. Since the limb was denervated, the only agency which could have caused contraction in the presence of increased blood pressure must have been brought by the blood stream. And, since the phenomenon disappeared on exclusion of the adrenals, the conclusion was drawn that adrenal secretions, poured out in consequence of reflex stimulation, produced the observed vaso-constric- tion. The following year, Hitchings, Sloan and Austin, 4 using our method, found that after great fear and rage had been induced in a cat, the adrenin reaction was clearly demonstrated. The reaction did not occur, however, if the splanchnic ADEENAL SECEETION IN EMOTIONS 63 nerves had been previously severed. In 1913, also, Levy 5 reported that sciatic stimulation occasioned irregularity of the denervated heart, an effect likewise seen when a splanchnic nerve was stimu- lated, but lacking after adrenal extirpation in the stimulated side. Again the conclusion was drawn that the effect was due to adrenin discharged re- flexly. Similar evidence was reported in 1917 by Florovsky, 6 with reference to the denervated sal- ivary gland. Furthermore, Eedfield noted (1917) 7 that nervous excitement causes a contraction of the melanophores in the denervated skin of the horned toad, a reaction which is absent after re- moval of the adrenal glands. Eecently I have myself 8 completely confirmed all our earlier work, by using the denervated heart as an indicator. The only opposition to all these positive results is that offered by Stewart and Eogoff, who failed to dem- onstrate any effects of sensory stimulation in adrenal activity. Since they used a peculiar method, however, known to disturb profoundly the region innervated by the splanchnic nerves, their negative results cannot be regarded as offsetting the positive findings of all other observers. The logic of all these experiments may be briefly summed up. That the adrenal glands are subject to splanchnic influence has been demonstrated anatomically and by the physiological effects of their secretion after artificial stimulation of the splanchnic nerves. Impulses are normally sent along these nerves, in the natural conditions of 64 BODILY CHANGES life, when animals become greatly excited, as in fear and rage and pain. There is every probabil- ity, therefore, that these glands are stimulated to extra secretion at such times. Both by an ex- ceedingly delicate biological test (intestinal mus- cle) and by an examination of the glands them- selves, clear evidence has been secured that in pain and deep emotion the glands do, in fact, pour out an excess of adrenin into the circulating blood. Here, then, is a remarkable group of phenomena a pair of glands stimulated to activity in times of strong excitement and by such nerve impulses as themselves produce at such times profound changes in the viscera ; and a secretion given forth into the blood stream by these glands, which is capable of inducing by itself, or of augmenting, the nervous influences which induce the very changes in the viscera which accompany suffering and the major emotions. What may be the sig- nificance of these changes, occurring when condi- tions of pain and great excitement experiences common to animals of most diverse types and probably known to their ancestors for ages past lay hold of the bodily functions and determine the instinctive responses? Certain remarkable effects of injecting adrenin into the blood have for many years been more or less well recognized. For example, when injected it causes liberation of sugar from the liver into ADRENAL SECRETION IN EMOTIONS 65 the blood stream. It relaxes the smooth muscle of the bronchioles. Some old experiments indi- cated that it acts as an antidote for muscular fatigue. It alters the distribution of the blood in the body, driving it from the abdominal viscera into the heart, lungs, central nervous system and limbs. And there was some evidence that it ren- ders more rapid the coagulation of the blood. There may be other activities of adrenin not yet discovered it may co-operate with the products of other glands of internal secretion. And other glands of internal secretion may be stimulated by sympathetic impulses. But we were not concerned with these possibilities. We wished to know whether the adrenin poured out in pain and emo- tional excitement produced or helped to produce the same effects that follow the injection of adre- nin. Our later researches were directed towards securing answers to this question. REFERENCES 1 Embden and v. Furth : Ilofmeister's Beitnige zur cliemi- scbeu Physiologie und Fathologie, 19O4, iv, p. 423. 2 Elliott : Journal of Physiology, 1005, xxxii, p. 448. s Anrep : Journal of Physiology, 1912, xiv, p. 307. 4 Hltchings, Sloan and Austin : Cleveland Medical Journal, 1913, xii, p. G86. e Levy : Heart, 1913, iv, p. 342. o Florovsky : Bulletin de I'AcadSmie Impgriale des Sciences, Petrograd, 1917, ix, p. 119. TRedfield: Journal of Experimental Zoo'logy, 1918, xxvi, p. 295. s Cannon: American Journal of Physiology, 1919, 1, p. 399. 9 Stewart and Rogoff : Journal of Experimental Medicine, 1917, xxvi, p. 637. CHAPTER V THE INCREASE OF BLOOD SUGAK IN PAIN AND GREAT EMOTION Sugar is the form in which carbohydrate mate- rial is transported in organisms ; starch is the stor- age form. In the bodies of animals that have been well fed the liver contains an abundance of glycogen or "animal starch," which may be called upon in times of need. At such times the glycogen is changed, and set free in the blood as sugar. Ordinarily there is a small percentage of sugar in the blood from 0.06 to 0.1 per cent. When only this small amount is present the kidneys are capable of preventing its escape in any noteworthy amount. If the percentage rises to the neighbor- hood of 0.2-0.3 per cent, however, the sugar passes the obstacle set up by the kidneys, and is readily demonstrable in the urine by ordinary tests. The condition of "glycosuria," therefore, may prop- erly be considered, in certain circumstances, as evidence of increased sugar in the blood. The in- jection of adrenin can liberate sugar from the 66 INCEEASE OF BLOOD SUGAE 67 liver to such an extent that glycosuria results. Does the adrenal secretion discharged in pain and strong emotional excitement play a role in pro- ducing glycosuria under such conditions? In clinical literature scattered suggestions are to be found that conditions giving rise to emo- tional states may be the occasion also of more or less permanent glycosuria. Great grief and pro- longed anxiety during a momentous crisis have been regarded as causes of individual instances of diabetes, and anger or fright has been followed by an increase in the sugar excreted by persons who already have the disease. Kleen 1 cites the instance of a German officer whose diabetes and whose Iron Cross for valor both came from a stressful experience in the Franco-Prussian War. The onset of the disease in a man directly after his wife was discovered in adultery is described by Naunyn; 2 and this author also mentions two cases in his own practice one started during the bombardment of Strassburg (1870), the other started a few days after a companion had shot himself. In cases of mental disease, also, states of depression have been described accompanied by sugar in the urine. Schultze 3 has reported that in these cases the amount of glycosuria is de- pendent on the degree of depression, and that the greatest excretion of sugar occurs in the fear- psychoses. Eaimann 4 has reported that in both 68 BODILY CHANGES melancholia and mania the assimilation limit of sugar may be lowered. Similar results in the insane have recently been presented by Mita, 5 and by Folin and Denis. 6 The latter investiga- tors found glycosuria in 12 per cent of 192 insane patients, most of whom suffered from depression, apprehension, or excitement. And Arndt 7 has observed glycosuria appearing and disappearing as alcoholic delirium appeared and disappeared in his patients. Although clinical evidence thus indicates an emotional origin of some cases of diabetes and glycosuria, the intricacies of existence and the complications of disease in human beings throw some doubt on the value of that evidence. Both Naunyn 8 and Hirsclifeld, although mentioning instances of diabetes apparently due to an emo- tional experience, urge a skeptical attitude to- ward such statements. It is desirable, therefore, that the question of an emotional glycosuria be tested under simpler and more controllable con- ditions. "Emotional glycosuria" in experimental animals has indeed been referred to by Water- man and Smit 9 and more recently by Hender- son and Underbill. 10 Both these references, how- ever, are based on the work of Bohm and Hoff- mann, 11 reported in 1878. INCEEASE OF BLOOD SUGAR 69 GLYCOSURIA FROM PAIN Bohm and Hoffmann found that cats, when bound to an operating board, a tube inserted into the trachea (without anesthesia), and in some instances a catheter inserted into the urethra through an opening above the pubis, had in about half an hour an abundance of sugar in the urine. In three determinations sugar in the blood proved slightly above "normal" so long as sugar was ap- pearing in the urine, but returned to "normal" as the glycosuria disappeared. Since they were able to produce the phenomenon by simply bind- ing animals to the holder, they called it "Fes- selungsdiabetcs." As possible causes of this glycosuria in bound animals, they considered opening the trachea, cooling, and pain. The first two they readily eliminated, and still they found sugar excreted. Pain they could not obviate, and since, without binding the animals, they caused glycosuria by merely stimulating the sciatic nerves, they con- cluded that painful confinement was itself a suffi- cient cause. Other factors, however, such as cool- ing and circulatory disturbances, probably co- operated with pain, they believed, to produce the result. Their observations on cats have been proved true also of rabbits; 12 and recently it has been shown that an operation involving some pain increases blood sugar in dogs. 13 Temporary gly- 70 BODILY CHANGES cosuria has likewise been noted in association with intense pain in human beings. Inasmuch as Bohm and Hoffmann did not men- tion the emotional element in discussing their re- sults, and inasmuch as they admitted that they could not obviate from their experimental pro- cedure pain, which they themselves proved was effective in causing glycosuria, designating what they called "Fesselungsdiabetes" as "emotional glycosuria" is not justified. EMOTIONAL GLYCOSURIA The discovery that during strong emotion adre- nal secretion is increased, and the fact that injec- tion of adrenin gives rise to glycosuria, suggested that glycosuria might be called forth by emotional excitement, and then that even without the painful element of Bohm and Hoffmann's experiments, sugar might be found in the urine. The testing of this possibility was undertaken by A. T. Shohl, W. S. Wright and myself in 1911. Our first procedure was a repetition of Bohm and Hoffmann's experiments, freed from the factor of pain. The animals (cats) were bound to a comfortable holder, which left the head unfastened. This holder I had used hundreds of times in X-ray studies of digestion, with many different animals, without causing any signs of even so much as uneasiness. Just as in obser- INCEEASE OF BLOOD SUGAR 71 vations on the movements of the alimentary canal, however, so here, the animals reacted differently to the experience of being confined. Young males usually became quite frantic, and with eyes wide, pupils dilated, pulse accelerated, hairs of the tail more or less erect, they struggled, snarling and growling, to free themselves. Females, on the contrary, especially if elderly, were as a rule much more calm, and resignedly accepted the novel situation. According to differences in reaction the animals were left in the holder for periods varying in length from thirty minutes to five hours. In order to insure prompt urination, considerable quantities of water were given by stomach tube at the beginning of the experiment and in some cases again later. Arrangements were made for draining the urine promptly, when the animal was on the holder or when afterwards in a metal metab- olism cage, into a glass receiver containing a few drops of chloroform to prevent fermentation. The diet in all cases consisted of customary raw meat and milk. In every instance the urine was proved free from sugar before the animal was excited. In our series of observations twelve cats were used, and in every one a well-marked glycosuria was developed. The shortest periods of confine- ment to the holder which were effective were thirty 72 BODILY CHANGES and forty minutes ; the longest we employed, five hours. The average time required to bring about a glycosuria was less than an hour and a half; the average in seven of the twelve cases was less than forty minutes. In all cases no sugar was found in the urine passed on the day after the excitement. The promptness with w^hich the glycosuria de- veloped was directly related to the emotional state of the animal. Sugar was found early in animals which early showed signs of being frightened or in a rage, and much later in animals which took the experience more calmly. As cooling may result in increased sugar in the blood, and consequent glycosuria, the rectal tem- perature was observed from time to time, and it was found to vary so slightly that in these experi- ments it was a wholly negligible factor. In one cat the rectal temperature fell to 36 C. while the animal was bound and placed in a cold room (about 2 C.) for fifty minutes, but no sugar appeared in the urine. Further evidence that the appearance of sugar in the urine may arise purely from emotional ex- citement was obtained from three cats which gave negative results when bound in the holder for varying periods up to four hours. It was note- worthy that these animals remained calm and passive in their confinement. When, however, INCREASE OF BLOOD SUGAR 73 they were placed, separately, in a small wire cage, and were barked at by an energetic little dog, that jumped at them and made signs of attack, the cats became much excited, they showed their teeth, humped their backs, and growled defiance. This sham fight was permitted to continue for a half hour in each of the three cases. In each case the animal, which after four hours of bondage had ex- hibited no glycosuria, now had sugar in the urine. Pain, cooling, and bondage were not factors in these experiments. The animal was either fright- ened or enraged by the barking dog, and that ex- citement was attended by glycosuria. The sugar excreted in the twenty-four hours which included the period of excitement was de- termined by the Bertrand method. 14 It ranged from 0.024 gram to 1.93 grams, or from 0.008 gram to 0.62 gram per kilo body weight, for the twenty-four hours' quantity. The presence of sugar in the urine may be used as an indication of increased sugar in the blood, for unless injury has been done to the cells of the kidneys, they do not permit sugar to escape until the percentage in the blood has risen to a considerable degree. Thus, though testing the urine reveals the instances of a high content of blood sugar, it does not show the fine variations that appear when the blood itself is examined. Recently Scott 15 has concluded a thorough in- 74 BODILY CHANGES vestigation of the variations of blood sugar in cats, and has found that merely incidental conditions, producing even mild excitement, as indicated by crying or otherwise, result in a noticeable rise in the amount. Indeed, so sensitive is the sugar-lib- erating mechanism that all the early determina- tions of the "normal" content of sugar in blood which has been drawn from an artery or vein in the absence of anesthesia, are of very doubtful value. Certainly when care is taken to obtain blood suddenly from a tranquil animal, the per- centage (0.069, Scott; 0.088, Pavy) is much less than when the blood is drawn without anesthesia (0.15, Bohm and Hoffmann), or after light nar- cosis (0.282, Eona and Takahashi 16 ). Our observations on cats have since been found valid for rabbits. Eolly and Oppermann, Jacob- sen, and Hirsch and Eeinbach 17 have recently recorded that the mere handling of a rabbit pre- paratory to operating on it will increase the per- centage of blood sugar (in some cases from 0.10 to 0.23 and 0.27 per cent). Dogs are said to be much less likely to be disturbed by the nature of their surroundings than are rabbits and cats. Nevertheless, pain and excitement are such funda- mental experiences in animals that without much doubt the same mechanism is operative in all when these experiences occur. Probably, just as the digestion of dogs is disturbed by strong emotion, INCEEASE OF BLOOD SUGAR 75 the blood sugar likewise is increased, for sym- pathetic impulses occasion both changes.* Gib has given an account of a bitch that became much agitated when shut up, and after such enforced seclusion, but never otherwise, she excreted small quantities of sugar in the urine. 18 The results noted in these lower animals have been confirmed in human beings. One of my for- mer students, W. G. Smillie, found that four of nine medical students, all normally without sugar in their urine, had glycosuria after a hard exami- nation, and only one of the nine had glycosuria after an easier examination. The tests, which were positive with Fehling's solution, Nylander's reagent, and also with phenyl-hydrazine, were made on the first urine passed after the exam- ination. Furthermore, C. H. Fiske and I ex- amined the urine of twenty-five members of the Harvard University football squad immedi- ately after the final and most exciting contest of the season of 1913, and found sugar in twelve cases. Five of these positive cases were among substitutes not called upon to enter the game. The only excited spectator of the Har- * Since the foregoing sentences were written Hirsch and Eeinbach have reported (Zeitschrift fiir physiologische Chemie, 1914, xci, p. 292) a "psychic hyperglycemia" in dogs, that resulted from fastening the animals to a table. The blood sugar rose in one instance from 0.11 to 0.14 per cent, and in another from 0.09 to 0.16 per cent. 76 BODILY CHANGES vard victory whose urine was examined also had a marked glycosuria, which on the following day had disappeared. Other tests made on students before and after important scholastic examinations have been pub- lished by Folin, Denis and Smillie. 19 Of thirty- four second-year medical students tested, one had sugar before the examination as well as after- wards. Of the remaining thirty- three, six, or 18 per cent, had small but unmistakable traces of sugar in the urine passed directly following the ordeal. A similar study was made on second-year students at a women's college. Of thirty-six stu- dents who had no sugar in the urine on the day before, six, or 17 per cent, eliminated sugar with the urine passed immediately after the examina- tion. From the foregoing results it is reasonable to conclude that just as in the cat, dog, and rabbit, so also in man, emotional excitement produces tem- porary increase of blood sugars THE ROLE OP THE ADRENAL GLANDS IN EMOTIONAL GLYCOSURIA Since artificial stimulation of the splanchnic nerves produces glycosuria, 20 and since major emotions, such as rage and fright, are attended by nervous discharges along splanchnic pathways, glycosuria as an accompaniment of emotional ex- INCREASE OF BLOOD SUGAR 77 citement would naturally be expected to occur. To what extent the adrenal glands which, as already mentioned, are stimulated to increased secretion by excitement, might play a part in this process, has been in dispute. Removal of these glands or cutting of the nerve fibres supplying them, according to some observers, 21 prevents glycosuria after puncture of the fourth ventricle of the brain (the "sugar puncture," which typically induces glycosuria) and also after stimulation of the splanchnics. 22 On the other hand, Wert- heimer and Battez 23 have stated that removal of the glands does not abolish the effects of sugar puncture in the cat. It was questionable, there- fore, whether removal of the adrenal glands would affect emotional glycosuria. Evidence on this point I secured with Shohl and Wright in observations on three animals in which the adrenals were removed aseptically under ether. The animals selected had all become quickly ex- cited on being bound to the holder, and had mani- fested glycosuria after about an hour of confine- ment. In the operation, to avoid discharge of adrenin by handling, the adrenal veins were first tied, and then the glands freed from their attach- ments and removed as quickly and with as little manipulation as possible. In one cat the entire operation was finished in twenty minutes. In two of the cats a small catheter was introduced into the 78 BODILY CHANGES urethra through an incision, so that the bladder could be emptied at any time. In all three cases urine that was free from sugar was obtained soon after the operation. Al- though the animals deprived of their adrenals manifested a general lessening of muscular tone, they still displayed much of their former rage or excitement when bound. Indeed, one was more ex- cited after removal of the adrenals than before. That the animals might not be excessively cooled they were kept warm with coverings or an elec- tric heating pad. Although they were now bound for periods from two to three times as long as the periods required formerly to cause glycosuria, no trace of sugar was found in the urine in any instance. The evidence thus secured tends, there- fore, to support the view that the adrenal glands perform an important contributory role in the glycosuria resulting from splanchnic stimula- tion. Possibly the emotional element is in part ac- countable for the glycosuria observed after pain- ful stimulation, but conditions causing pain alone will reasonably explain it. As we have already seen, strong stimulation of sensory fibres causes the discharge of impulses along the splanchnic nerves, and incidentally calls forth an increased secretion of the adrenal glands. In glycosuria re- sulting from painful stimulation, as well as in emo- INCEEASE OF BLOOD SUGAE 79 tional glycosuria, the adrenal glands may be es- sential factors. Later the evidence will be given that sugar is the optimum source of muscular energy. In pass- ing, we may note that the liberation of sugar at a time when great muscular exertion is likely to be demanded of the organism may be interpreted as a highly interesting instance of biological adaptation. KEFEEENCES 1 Kleen: On Diabetes Mellitus and Glycosuria, Philadel- phia, 1900, pp. 22, 37-39. 2 Naunyn : Der Diabetes Mellitus, Vienna, 1898, p. 72. 3 Schultze : Verhandlungen der Gesellschaf t deutscher Naturforscher und Aerzte, Cologne, 1908, ii, p. 358. 4 Raimann: Zeitschrift fiir Heilkunde, 1902, xxiii, Ab- theilung iii, pp. 14, 19. 5 Mita : Monatshef te f iir Psychiatrie und Neurologic, 1912, xxxii, p. 159. 6 Folin, Denis and Smillie: Journal of Biological Chem- istry, 1914, xvii, p. 519. 7 Arndt : Zeitschrift fur Nervenheilkunde, 1897, x. p. 436. 8 Naunyn : Loc. cit. f p. 73 ; Hirschfeld : Die Zuckerkrank- heit, Leipzig, 1902, p. 45. 9 Waterman and Smit: Archiv fiir die gesammte Physi- ologic, 1908, cxxiv, p. 205. 10 Henderson and Underbill : American Journal of Physi- ology, 1911, xxviii, p. 276. 11 Bohm and Hoffmann : Archiv fiir experimentelle Pa- thologie und Pharmakologie, 1878, viii, p. 295. 12 Eckhard : Zeitschrift fiir Biologic, 1903, xliv, p. 408. 18 Loewy and Rosenberg : Biochemische Zeitschrift, 1913, Ivi, p. 114. 14 See Abderhalden : Handbuch der biochemischen Ar- beitsmethoden, Berlin, 1910, ii, p. 181. 80 BODILY CHANGES 15 Scott : American Journal of Physiology, 1914, xxxiv, p. 283. 16 Cited by Scott: Loc. cit., p. 296. 17 Roily and Oppermann: Biochemischo Zeitschrift, 1913, xlix, p. 201. Jacobscn: Ibid., 1913, li, p. 449. Hirsch and Reinbach: Zeitschrift fur physiologische Chemie, 1913, Ixxxvii, p. 122. 18 Cited by Klecn: Loc. cit., p. 37. 19 Folin, Denis and Smillie: Loc. cit.,, p. 520. 20 See Macleod : American Journal of Physiology, 1907, xix, p. 405, also for other references to literature. 21 See Meyer: Comptes rend us de la Societe de Biologic, 1906, Iviii, p. 1123; Nishi : Archiv fur experimentelle Pa- thologic und Pharmakologie, 1909, Ixi, p. 416. 22 Gautrelct and Thomas: Comptes rcndus de la So- ciete de Biologic, 1909, Ixvii, p. 233; and Macleod: Pro- ceedings of the Society for Experimental Biology and Medi- cine, 1911, viii, p. 110 (true for left adrenal and left splanch- nic). 23 Wertheimer and Battez : Archives Internationales cle Physiologic, 1910, ix, p. 392. CHAPTER VI IMPEOVED CONTRACTION OF FATIGUED MUSCLE AFTER SPLANCHNIC STIMULATION OF THE ADRENAL GLAND In the older literature on the adrenal glands the deleterious effect of their absence, or the beneficial effect of injected extracts, on the contraction of skeletal muscle was not infrequently noted. As evidence accumulated, however, tending to prove an important relation between the extract of the adrenal medulla (adrenin) and the sympathetic nervous system, the relations with the efficiency of skeletal muscle began to receive less consideration. The muscular weakness of persons suffering from diseased adrenals (Addison's disease) was well recognized before experimental work on the glands was begun. Experiments on rabbits were reported in 1892 by Albanese, 1 who showed that muscles which were stimulated after removal of the glands were much more exhausted than when stimulated the same length of time in the same animal before the removal. Similarly Boi- 81 82 BODILY CHANGES net 2 reported, in 1895, that rats recently deprived of their adrenals were much more quickly ex- hausted in a revolving cage than were normal animals. That extract of the adrenal glands has the power of increasing and prolonging the contraction of normal resting skeletal muscle, was noted by Oli- ver and Schaefer, 3 in their classic original study of the action of adrenal substance. But a recent examination of this effect by Takayasu, 4 who em- ployed adrenin alone, has failed to confirm the earlier observations. It should be understood that these observations, however, were made on resting and not on fatigued muscle. On fatigued muscle a beneficial effect of adrenal extract, even when applied to the solution in which the isolated muscle was contracting, was claimed by Dessy and Grandis, 5 who studied the phenomenon in a salamander.* Further evidence leading to the same conclusion was offered in a discriminat- * These earlier investigations, in which an extract of the entire gland was used, made no distinction between the action of the medulla and that of the cortex. It may be that the weakness following removal or disease of the adrenals is due to absence of the cortex (see Hoskins and Wheelon : Am- erican Journal of Physiology, 1914, xxxiv, p. 184). Such a possible effect, however, should not be confused with the demonstrable influence of injected adrenin (derived from the adrenal medulla alone) and the similar effects from adrenal secretion caused by splanchnic stimulation. CONTRACTION OF FATIGUED MUSCLE 83 ing paper by Panella. 6 He found that in cold- blooded animals the active principle of the adre- nal medulla notably reinforced skeletal muscle, prolonging its ability to do work, and improv- ing its contraction when fatigued. In warm- blooded animals the same effects were observed, but only after certain experimental procedures, such as anesthesia and section of the bulb, had changed them to a condition resembling the cold- blooded. The foregoing evidence indicates that removal of the adrenals has a debilitating effect on muscu- lar power, and that injection of extracts of the glands has an invigorating effect. It seemed pos- sible, therefore, that increased secretion of the adrenal glands, whether from direct stimulation of the splanchnic nerves or as a reflex result of pain or the major emotions, might act as a dyna- mogenic factor in the performance of muscular work. With this possibility in mind L. B. Nice and I 7 first concerned ourselves in a research which we conducted in 1912. The general plan of the investigation consisted primarily in observing the effect of stimulating the splanchnic nerves, isolated from the spinal cord, on the contraction of a muscle whose nerve, also isolated from the spinal cord, was rhyth- mically and uniformly excited with break induc- tion shocks. When a muscle is thus stimulated it 84 BODILY CHANGES at first responds by strong contractions, but as time passes the contractions become weaker, the degree of shortening of the muscle becomes less, and in this state of lessened efficiency it may con- tinue for a long period to do work. The tired muscle which is showing continuously and evenly its inability to respond as it did at first, is said to have reached the "fatigue level." This level serves as an excellent basis for testing influences that may have a beneficial effect on muscular perform- ance, for the benefit is at once manifested in greater contraction. In the experimental arrangement which we used, only a connection through the circulating blood existed between the splanchnic region and the muscle all nervous relations were severed. Any change in muscular ability, therefore, occurring when the splanchnic nerve is stimulated, must be due to an alteration in the quantity or qual- ity of the blood supplied to the laboring muscle. Cats were used for most experiments, but re- sults obtained with cats were confirmed on rab- bits and dogs. To produce anesthesia in the cats and rabbits, and at the same time to avoid the fluctuating effects of ether, urethane (2 grams per kilo body- weight) was given by a stomach tube. The animals were fastened back downward, over an electric warming pad, to an animal holder. CONTEACTION OF FATIGUED MUSCLE 85 Care was taken to maintain the body temperature at its normal level throughout each experiment. THE NERVE- MUSCLE PREPARATION The muscle selected to be fatigued was usually the extensor of the right hind foot (the tibialis anticus), though at times the common extensor muscle of the digits of the same foot was em- ployed. The anterior tibial nerve which supplies these muscles was bared for about two centimeters, severed toward the body, and set in shielded elec- trodes, around which the skin was fastened by spring clips. Thus the nerve could be protected, kept moist, and stimulated without stimulation of neighboring structures. By a small slit in the skin the tendon of the muscle was uncovered, and after a strong thread was tied tightly about it, it was separated from its insertion. A nerve-muscle preparation was thereby made which was still con- nected with its proper blood supply. The prepa- ration was fixed firmly to the animal holder by thongs looped around the hock and the foot, i. e., on either side of the slit through which the tendon emerged. The thread tied to the tendon was passed over a pulley and down to a pivoted steel bar which bore a writing point. Both the pulley and this steel writing lever were supported in a rigid tri- pod. In the earliest experiments the contracting 86 BODILY CHANGES muscle was made to lift weights (125 to 175 grams) ; in all the later observations, however, the muscle pulled against a spring attached below the steel bar. The tension of the spring as the muscle began to lift the lever away from the sup- port was, in most of the experiments, 110 grams, with an increase of 10 grams as the writing point was raised 4.5 millimeters. The magnification of the lever was 3.8. The stimuli delivered to the anterior tibial nerve were, in most experiments, single break shocks of a value barely maximal when applied to the fresh preparation. The rate of stimulation varied be- tween 60 and 300 per minute, but was uniform in any single observation. A rate which was found generally serviceable was 180 per minute. Since the anterior tibial nerve contains fibres affecting blood-vessels, as well as fibres causing contraction of skeletal muscle, the possibility had to be considered that stimuli applied to it might disturb the blood supply of the region. Constric- tion of the blood vessels would be likely to pro- duce the most serious disturbance, by lessening the blood flow to the muscle. The observations of Bowditch and Warren, 8 that vasodilator rather than vasoconstrictor effects are produced by single induction shocks repeated at intervals of not more than five per second, reassured us as to the danger of diminishing the blood supply, for CONTRACTION OF FATIGUED MUSCLE 87 * the rate of stimulation in our experiments never exceeded five per second and was usually two or three. Furthermore, in using these different rates we have never noted any result which could rea- sonably be attributed to a diminished circulation. THE SPLANCHNIC PREPARATION The splanchnic nerves were stimulated in vari- ous ways. At first only the left splanchnics in the abdomen were prepared. The nerves, sepa- rated from the spinal cord, were placed upon shielded electrodes. The form of electrodes which was found most satisfactory was that illustrated FIGURE 10. The shielded electrodes used in stimulating the splanchnic nerves. For description see text. in Fig. 10. The instrument was made of a round rod of hard wood, bevelled to a point at one end, and grooved on the two sides. Into the grooves were pressed insulated wires ending in platinum hooks, which projected beyond the bevelled sur- face. Around the rod was placed an insulating rubber tube which was cut out so as to leave the hooks uncovered when the tube was slipped down- ward. In applying the electrodes the left splanchnic nerves were first freed from their surroundings and tightly ligatured as close as possible to their 88 . BODILY CHANGES origin. By means of strong compression the con- ductivity of the nerves was destroyed central to the ligature. The electrodes were now fixed in place by thrusting the sharp end of the wooden rod into the muscles of the back. This was so done as to bring the platinum hooks a few milli- meters above the nerves. With a small seeker the nerves were next gently lifted over the hooks, and then the rubber tube was slipped downward until it came in contact with the body wall. Ab- sorbent cotton was packed about the lower end of the electrodes, to take up any fluid that might appear; and finally the belly wall was closed with spring clips. The rubber tube served to keep the platinum hooks from contact with the muscles of the back and the movable viscera, while still per- mitting access to the nerves which were to be stimulated. This stimulating apparatus could be quickly applied, and, once in -place, needed no further attention. In some of the experiments both splanchnic nerves were stimulated in the thorax. The rubber-covered electrode proved quite as serviceable there as in the abdo- men. The current delivered to the splanchnic nerves was a rapidly interrupted induced current of such strength that no effects of spreading were notice- able. That splanchnic stimulation causes secre- tion of the adrenal glands has been proved in CONTRACTION OF FATIGUED MUSCLE 89 many different ways which' have already been de- scribed (see p. 41). THE EFFECTS OF SPLANCHNIC STIMULATION ON THE CONTRACTION OF FATIGUED MUSCLE When skeletal muscle is repeatedly stimulated by a long series of rapidly recurring electric shocks, its strong contractions gradually grow weaker until a fairly constant condition is reached. The record then has an even top the muscle has reached the "fatigue level." The effect of splanch- nic stimulation was tried when the muscle had been fatigued to this stage. The effect which was often obtained by stimulating the left splanchnic nerves is shown in Fig. 11. In this instance the muscle while relaxed supported no weight, and FIGURE 11. Upper record, contraction of the tibialis anticus, 80 times a minute, lifting a weight of 125 grams. Lower record, stimulation of the left splanchnic nerves, two minutes. Time, half minutes. while contracting lifted a weight of 125 grams. The rate of stimulation was 80 per minute. 90 BODILY CHANGES The muscle record shows a brief initial rise from the fatigue level, followed by a drop, and that in turn by another, prolonged rise. The maxi- mum height of the record is 13.5 millimeters, an increase of 6 millimeters over the height recorded before splanchnic stimulation. Thus the muscle was performing for a short period 80 per cent more work than before splanchnic stimulation, and for a considerably longer period exhibited an in- termediate betterment of its efficiency. THE FIRST RISE IN THE MUSCLE EECORD The brief first elevation in the muscle record when registered simultaneously with arterial blood pressure is observed to occur at the same time FIGURE 12. Top record, arterial blood pressure with membrane manometer. Mid- dle record, contractions of tibialis anticus loaded with 125 grams and stimulated 80 times a minute. Bottom record, splanchnic stimulation (two minutes). Time, half min- utes. CONTEACTION OF FATIGUED MUSCLE 91 with the sharp initial rise in the blood-pressure curve (see Fig. 12). The first sharp rise in blood' pressure is due to contraction of the vessels in the area of distribution of the splanchnic nerves, for it does not appear if the alimentary canal is removed, or if the celiac axis and the superior and inferior mesenteric arteries are ligated. The betterment of the muscular contraction is prob- ably due directly to the better blood supply result- ing -from the increased pressure, for if the adrenal veins are clipped and the splanchnic nerves are stimulated, the blood pressure rises as before and at the same time there may be registered a higher contraction of the muscle. THE PROLONGED KISE IN THE MUSCLE HECORD As Fig. 12 shows, the initial quick uplift in the blood-pressure record is quickly checked by a drop. This rapid drop does not appear when the adrenal veins are obstructed. A similar difference in blood-pressure records has been noted before and after excision of the adrenal glands. As Elli- ott, 9 and as Lyman and 1 10 have shown, this sharp drop after the first rise, and also the subse- quent elevation of blood pressure, are the conse- quences of liberation of adrenal secretion into the circulation. Fig. 12 demonstrates that the pro- longed rise of the muscle record begins soon after this characteristic drop in blood pressure. 92 BODILY CHANGES If after clips have been placed on the adre- nal veins so that no blood passes from them, the splanchnic nerves are stimulated, and later the clips are removed, a slight but distinct improve- ment in the muscular contraction occurs. As in the experiments of Young and Lehinann, 1X in which the adrenal veins were tied for a time and then released, the release of the blood which had been pent in these veins was quickly followed by a rise of blood pressure. The volume of blood thus restored to circulation was too slight to ac- count for the rise of pressure. In conjunction with the evidence that splanchnic stimulation calls forth adrenal secretion, the rise may reasonably be attributed to that secretion. The fact should be noted, however, that in this instance the prolonged improvement in muscular contraction did not ap- pear until the adrenal secretion had been admitted to the general circulation. Many variations in the improvement of activity in fatigued muscle after splanchnic stimulation were noted in the course of our investigation. The improvement varied in degree, as indicated by in- creased height of the record. In some instances the height of contraction was doubled a better- ment by 100 per cent ; in other instances the con- traction after splanchnic stimulation was only a small fraction higher than that preceding the stim- ulation; and in still other instances there was no CONTRACTION OF FATIGUED MUSCLE 93 betterment whatever. Never, in our experience, were the augmented contractions equal to the original strong contractions of the fresh muscle. The improvement also varied in degree as in- dicated by persistence of effect. In some in- stances the muscle returned to its former working level within four or five minutes after splanchnic stimulation ceased (see Fig. 11) ; and in other cases the muscle continued working with greater effi- ciency for fifteen or twenty minutes after the stim- ulation. THE Two FACTORS: ARTERIAL PRESSURE AND ADRENAL SECRETION The evidence just presented has shown that splanchnic stimulation improves the contraction of fatigued muscle. Splanchnic stimulation, however, has two effects it increases general arterial pres- sure and it also causes a discharge of adrenin from the adrenal glands. The questions now arise Does splanchnic stimulation produce the improve- ment in muscular contraction by increasing the arterial blood pressure and thereby flushing the laboring muscles with fresh blood? Or does the adrenin liberated by splanchnic stimulation act itself, specifically, to improve the muscular con- traction? Or may the two factors cooperate? These questions will be dealt with in the next two chapters. 94 BODILY CHANGES REFERENCES 1 Albanese : Archives Italiennes de Biologie, 1892, xvii, p. 243. 2 Boinet : Comptes rendus, Societe de Biologie, 1895, xlvii, pp. 273, 498. 3 Oliver and Schafer: Journal of Physiology, 1895, xviii, p. 263. See also Radwanska, Anzeiger der Akademie, Krakau, 1910, pp. 728-736. Reviewed in Zentralblatt fur Biochemie und Biophysik, 1911, xi, p. 467. ^Takayasu: Quarterly Journal of Experimental Physiology, 1916, Ix, p. 347. c Dessy and Grandis : Archives Italiennes de Biologie, 1904, xli, p. 231. o Panella : Archives Italiennes de Biologie, 1907, xlviii, p. 462. 7 Cannon and Nice : American Journal of Physiology, 1913, xxxii, p. 44. s Bowdftch and Warren : Journal of Physiology, 1886, vii, p. 438. a Elliott : Journal of Physiology, 1912, xliv, p. 403. 10 Cannon and Lyman : American Journal of Physiology, 1913, xxxi, p. 376. 11 Young and Lehmann : Journal of Physiology, 1908, xxxvii, p. liv. CHAPTEE VII THE EFFECTS ON CONTRACTION OF FATIGUED MUSCLE OF VARYING THE ARTERIAL BLOOD PRESSURE That great excitement is accompanied by sym- pathetic innervations which increase the contrac- tion of the small arteries, render unusually forc- ible the heart beat, and consequently raise arterial pressure, has already been pointed out (see p. 26). Indeed, the counsel to avoid circumstances likely to lead to such excitement, which is given to per- sons with hardened arteries or with weak hearts, is based on the liability of serious consequences, either in the heart or in the vessels, that might arise from an emotional increase of pressure in these pathological conditions. That great muscu- lar effort also is accompanied by heightened arte- rial pressure is equally well known, and is avoided by persons likely to be injured by it. Both in ex- citement and in strong exertion the blood is forced in large degree from the capacious vessels of the abdomen into other parts of the body. In excite- 95 96 BODILY CHANGES ment the abdominal arteries and veins are con- tracted by impulses from the splanchnic nerves. In violent effort the diaphragm and the muscles of the belly wall are voluntarily and antagonistic- ally contracted in order to stiffen the trunk as a support for the arms ; and the increased abdominal pressure which results forces blood out of that region and does not permit reaccumulation. The general arterial pressure in man, as McCurdy l has shown, may suddenly rise during extreme physical effort, from approximately 110 millime- ters to 180 millimeters of mercury. THE EFFECT OF INCREASING ARTERIAL PRESSURE What effect the increase of arterial pressure, re- sulting from excitement or physical strain, may have on muscular efficiency, has received only slight consideration. Nice and I found there was need of careful study of the relations between arterial pressure and muscular ability, and, in 1913, one of my students, C. M. Gruber, under- took to make clearer these relations. The methods of anesthesia and stimulation used by Gruber were similar to those described in the last chapter. The arterial blood pressure was registered from the right carotid or the femoral artery by means of a mercury manometer. A time marker indicating half-minute intervals was placed at the atmospheric pressure level of thfc FATIGUE AND BLOOD PEESSUEE 97 manometer. And since the blood-pressure style, the writing point of the muscle lever, and the time signal were all set in a vertical line on the surface of the recording drum, at any given muscular con- traction the height of blood pressure was simul- taneously registered. To increase general arterial pressure two meth- ods were used: the spinal cord was stimulated in the cervical region through platinum electrodes, or the left splanchnic nerves were stimulated after the left adrenal gland had been excluded from the circulation. This was done in order to avoid any influence which adrenal secretion might exert. It is assumed in these experiments that vessels sup- plying active muscles would be actively dilated, as Kaufmamx 2 has shown, and would, therefore, in case of a general increase of blood pressure, de- liver a larger volume of blood to the area they supply. The effects of increased arterial pressure arc illustrated in Figs. 13, 14 and 15. In the ex- periment represented in Fig. 13, the rise of blood pressure was produced by stimulation of the cer- vical cord, and in Figs. 14 and 15 by stimulation of the left splanchnic nerves after the left adre- nal gland had been tied off. The original blood pressure in Fig. 13 was 120 millimeters of mercury. This was increased by 62 millimeters, with a rise of only 8.4 per cent in the height of contraction of the fatigued muscle. 98 BODILY CHANGES FIGURE 13. In this and the following records, the upper curve indicates the blood pressure, the middle line muscu- lar contraction, and the lower line the time in 30 seconds (also zero blood pressure.) Between the arrows the exposed cervical spinal cord was stimulated. In Fig. 14 the original blood pressure was 100 millimeters of mercury. By increasing this pres- FATIGUE AND BLOOD PBESSURE 99 sure 32 millimeters there resulted simultaneous betterment of 9.8 per cent in the height of muscu- lar contraction. In Fig. 14 B the arterial pres- sure was raised 26 millimeters and the height of A B C FIGURE 14. Stimulation of the left splanchnic nerves (left adrenal gland tied off) during the periods indicated by the arrows. contraction increased correspondingly 7 per cent. In Fig. 14 C no appreciable betterment can be seen although the blood pressure rose 18 millimeters. In Fig. 15 the original blood pressure was low 68 millimeters of mercury. This was increased in Fig. 15 A by 18 millimeters (the same as in 100 BODILY CHANGES Fig. 14 C without effect), and there resulted an in- crease of 20 per cent in the height of contraction. In Fig. 15 B the pressure was raised 24 millime- A B c FIGURE 15. During the periods indicated in the time line the left splanchnic nerves were stimulated. The vessels of the left adrenal gland were tied off. ters with a corresponding increase of 90 per cent in the muscular contraction ; and in Fig. 15 C 30 millimeters with a betterment of 125 per cent. Comparison of Figs. 13, 14 and 15 reveals that the improvement of contraction of fatigued mus- cle is much greater when the blood pressure is raised, even slightly, from a low level, than when it is raised, perhaps to a very marked degree, from a high level. In one of the experiments per- formed by Nice and myself the arterial pressure FATIGUE AND BLOOD PRESSURE 101 was increased by splanchnic stimulation from the low level of 48 millimeters of mercury to 110 milli- meters, and the height of the muscular contrac- tions was increased about sixfold (see Fig. 16). FIGURE 16. The bottom record (zero of blood pressure) shows stimulation of left splanchnics; between the arrows the pressure was kept from rising by compression of heart. Results confirming those described above were obtained by Gruber in a study of the effects of splanchnic stimulation on the irritability of mus- cle when fatigued. In a series of eleven observa- tions the average value of the barely effective stimulus (the "threshold" stimulus) had to be in- creased as the condition of fatigue developed. It 102 BODILY CHANGES was increased for the nerve-muscle by 25 per cent and for the muscle by 75 per cent. The left splanchnic nerves, disconnected from the left adre- nal gland, were now stimulated. The arterial pres- sure, which had varied between 90 and 100 milli- meters of mercury, was raised at least 40 milli- meters. As a result of splanchnic stimulation there was an average recovery of 42 per cent in the nerve-muscle and of 46 per cent in the muscle. The increased general blood pressure was effec- tive, therefore, quite apart from any possible action of adrenal secretion, in largely restoring to the fatigued structures their normal irritability. THE EFFECT OF DECREASING ARTERIAL PRESSURE Inasmuch as an increase in arterial pressure produces an increase in the height of contraction of fatigued muscle, it is readily supposable that a decrease in the pressure would have the oppo- site effect. Such is the case only when the blood pressure falls below the region of 90 to 100 milli- meters of mercury. Thus if the arterial pressure stands at 150 millimeters of mercury, it has to fall approximately 55 to 65 millimeters before causing a decrease in the height of contraction. Fig. 17 is the record of an experiment in which the blood pressure was lowered by lessening the output of blood from the heart by compressing the thorax. The record shows that when the pressure FATIGUE AND BLOOD PKESSUKE 103 was lowered from 120 to 100 millimeters of mer- cury (A), there was no appreciable decrease in the height of contraction; when lowered to 90 FIGURE 17. The arrows indicate the points at which the thorax began to be compressed in order to lessen the output of blood from the heart. millimeters (B), there resulted a decrease of 2.4 per cent; when to 80 millimeters of mercury (C), a decrease of 7 per cent; and when to 70 milli- meters (D), a decrease of 17.3 per cent. Eesults similar to those represented in Fig. 17 were ob- tained by pulling on a string looped about the 104 BODILY CHANGES aorta just above its iliac branches, thus lessening the flow to the hind limbs. The region of 90 to 100 millimeters of mercury may therefore be regarded as the critical region at which a falling blood pressure begins to be ac- companied by a concurrent lessening of the effi- ciency of muscular contraction, when the muscle is kept in continued activity. It is at that region that the blood flow is dangerously near to being inadequate. AN EXPLANATION OF THE EFFECTS OF VARYING THE ARTERIAL PRESSURE How are these effects of increasing and decreas- ing the arterial blood pressure most reasonably explained? There is abundant evidence that fa- tigue products accumulate in a muscle which is doing work, and also that these metabolites inter- fere with efficient contraction. As Eanke 3 long ago demonstrated, if a muscle, deprived of circu- lating blood, is fatigued to a standstill, and then the circulation is restored, the muscle again re- sponds for a short time to stimulation, because the waste has been neutralized or swept away by the fresh blood. When the blood pressure is at its normal height for warm-blooded animals (about 120 millimeters of mercury, see Fig. 13), the flow appears to be adequate to wash out the depressive metabolites, at least in the single muscle FATIGUE AND BLOOD PRESSURE 105 used in these experiments, because a large rise of pressure produces but little change in the fatigue level. On the other hand, when the pressure is abnormally low, the flow is inadequate, and the waste products are permitted to accumulate and clog the action of the muscle. Under such circum- stances a rise of pressure has a very striking bene- ficial effect. It is noteworthy that the best results of adre- nin on fatigued muscle reported by previous ob- servers were obtained from studies on cold-blooded animals. In these animals the circulation is main- tained normally by an arterial pressure about one- third that of warm-blooded animals. Injection of adrenin in an amount which would not shut off the blood supply would, by greatly raising the arterial pressure, markedly increase the circulation of blood in the active muscle. In short, the conditions in cold-blooded animals are quite like those in tho pithed mammal with an arterial pressure of about 50 millimeters of mercury (see Fig, 1C). Under these conditions the improved circulation causes a remarkable recovery from fatigue. That notable results of adrenin on fatigue are observed in warm-blooded animals only when they are deeply anaesthetized or are deprived of the medulla was claimed by Panella. 4 He apparently believed that in normal mammalian conditions adrenin has little effect because quickly destroyed, whereas in 106 BODILY CHANGES the cold-blooded animals, and in mammals whose respiratory, circulatory, and thermogenic states are made similar to the cold-blooded by anaesthesia or pithing, the contrary is true. In accordance with our observations of the effects of blood pres- sure on fatigued muscle, we would explain Panel- la's results not as he has done but as due to two factors. First, the efficiency of the muscle, when blood pressure is low, follows the ups and downs of pressure much more directly than when the pressure is high. And second, a given dose of adrenin always raises a low blood pressure in atonic vessels. The improvement of circulation is capable of explaining, therefore, the main re- sults obtained in cold-blooded animals and in pithed mammals. Oliver and Schafer reported unusually effective contractions in muscles removed from the body after adrenal extract had been injected. As shown in Fig. 16, however, the fact that the circulation had been improved results in continued greater effi- ciency of the contracting muscle. Oliver and Schii- fer's observation may perhaps be accounted for on this basis. THE VALUE OF INCREASED ARTERIAL PRESSURE IN PAIN AND STRONG EMOTION As stated in a previous paragraph, there is evi- dence that the vessels supplying a muscle dilate FATIGUE AND BLOOD PRESSURE 107 when the muscle becomes' active. And although the normal blood pressure (about 120 millimeters of mercury) may be able to keep adequately sup- plied with blood the single muscle used in our in- vestigation, a higher pressure might be required when more muscles are involved in activity, for a more widely spread dilation might then reduce the pressure to the point at which there would be insufficient circulation in active organs. Further- more, with many muscles active, the amount of waste would be greatly augmented, and the need for abundant blood supply would thefeby to a like degree be increased. For both reasons a rise of general arterial pressure would prove advan- tageous. The high pressure developed in excite- ment and pain, therefore, might be specially ser- viceable in the muscular activities which are likely to accompany excitement and pain. In connection with the foregoing considerations, the action of adrenin on the distribution of blood in the body is highly interesting. By measuring alterations in the volume of various viscera and the limbs, Oliver and Schaf er 5 proved that the viscera of the splanchnic area e.g., the spleen, the kidneys, and the intestines suffer a consider- able decrease of volume when adrenin is adminis- tered, whereas the limbs into which the blood is forced from the splanchnic region actually in- crease in size. Haskins, Gunning, and Berry 6 108 BODILY CHANGES showed, and their work has been confirmed by others, 7 that with nerves intact adrenin causes active dilatation of the vessels in muscles and con- striction of cutaneous vessels. This action of adrenin indicates differences in the degree or character of sympathetic innervations. In other words, at times of pain and excitement sym-x pathetic discharges, probably aided by the adrenal secretion simultaneously liberated, will drive the blood out of the vegetative organs of the interior, which serve the routine needs of the body, into the skeletal muscles which have to meet by extra action the urgent demands of struggle or escape. But there are exceptions to the general state- ment that by adrenin the viscera are emptied of their blood. It is well known that adrenin has a vasodilator, not a vasoconstrictor, action on the arteries of the heart; it is well known also that adrenin affects the vessels of the brain and the lungs only slightly if at all. From this evidence we may infer that sympathetic impulses, though causing constriction of the arteries of the abdomi- nal viscera, have no effective influence on those of the pulmonary and intracranial areas and actually increase the blood supply to the heart. Thus the absolutely and immediately essential organs those the ancients called the "tripod of life" the heart, the lungs, the brain (as well as its instru- ments, the skeletal muscles) are in times of ex- FATIGUE AND BLOOD PRESSURE 109 citement abundantly supplied with blood taken from organs of less importance in critical mo- ments. This shifting of the blood so that there is an assured adequate supply to structures essential for the preservation of the individual may reason- ably be interpreted as a fact of prime biological significance. It will be placed in its proper setting when the other evidence of bodily changes in pain and excitement have been presented. REFERENCES 1 McCurdy : American Journal of Physiology, 1901, v, p. 98. 2 Kauf maiin : Archives de Physiologic, 1892, xxiv, p. 283. 3 Ranker Archiv fur Anatomic, 18G3, p. 446. 4 Panella : Archives Italiennes de Biologic, 1907, xlviii, p. 462. 5 Oliver and Schiifer : Journal of Physiology, 1895, xviii, p. 240. Hoskins, Gunning and Berry : American Journal of Physiology, 1916, xli, p. 513. 7 TIartman and Fraser: American Journal of Physiology, 1917, xliv, p. 353 ; Gruber : Ibid., 1918, xlv, p. 302 ; and Pearl- man and Vincent: Endocrinology, 1919, ill, p. 121. CHAPTER VIII THE SPECIFIC ROLE OF ADRENIN IN COUNTERACTING THE EFFECTS OF FATIGUE As a muscle approaches its fatigue level, its con- tractions are decreased in height. Higher contrac- tions will again be elicited if the stimulus is in- creased. Although these phenomena are well known, no adequate analysis of their causes has been advanced. A number of factors are probably operative in decreasing the height of contraction : (1) The using up of available energy-producing material; (2) the accumulation of metabolites in the fatigued muscle; (3) polarization of the nerve at the point of repeated electrical stimulation ; and (4) a decrease of irritability. It may be that there are interactions between these factors within the muscle, e. g., the second may cause the fourth. VARIATIONS OF THE THRESHOLD STIMULUS AS A MEASURE OF IRRITABILITY The last of the factors mentioned above the effect of fatigue on the irritability of the nerve- muscle combination, or on the muscle alone can no FATIGUE AND ADEENIN 111 be tested by determining variations in the least stimulus capable of causing the slightest contrac- tion, the so-called "threshold stimulus." As the irritability lessens, the threshold stimulus must necessarily be higher. The height of the threshold is therefore a measure of irritability. How does fatigue affect the irritability of nerve-muscle and muscle ? How is the irritability of fatigued struc- tures affected by rest? How is it influenced by adrenin or by adrenal secretion? Answers to these questions were sought in researches carried on by C. M. Gruber 1 in 1913. THE METHOD OF DETERMINING THE THRESHOLD STIMULUS The neuro-muscular arrangements used in these researches were in many respects similar to those already described in the account of experiments by Nice and myself. To avoid the influence of an anesthetic some of the animals were decerebrated under ether and then used as in the experiments in which urethane was the anesthetic. The nerve (the peroneus communis) supplying the tibialis an- ticus muscle was bared and severed ; and near the cut end shielded platinum electrodes were applied. These electrodes were used in fatiguing the muscle. Between these electrodes and the muscle other platinum electrodes could be quickly applied to de- termine the threshold stimulus and the tissue re- sistance. These second electrodes were removed 112 BODILY CHANGES except when in use, and when replaced were set always in the same position. Care was taken, be- fore replacing them, to wipe off moisture on the nerve or on the platinum points. For determining the threshold stimulus of the muscle the skin and other overlying tissues were cut away from the tibialis anticus in two places about 5 centimeters apart. Through these open- ings platinum needle electrodes could be thrust into the muscle whenever readings were to be taken. Local polarization was avoided by rein- serting the needles into fresh points on the exposed areas whenever new readings were to be taken. The tendon of the tibialis anticus was attached, as in the previous experiments, by a strong thread passing about pulleys to a lever which when lifted stretched a spring. During the determination of the threshold the spring was detached from the lever, so that only the pull of the lever itself (about 15 grams) was exerted on the muscle. The method of measuring the stimulating value of the electric current which was used in testing the threshold was that devised by E. G. Martin* of the Harvard Laboratory a method by which the strength of an induced electric shock is calculable in definite units. If the tissue resistance enters * For a full account of Dr. Martin's method of calculating the strength of electric stimuli, see Martin : The Measurement of Induction Shocks, New York, 1912. FATIGUE AND ADEENIN 113 into the calculation these are called units. When the threshold of the nerve-muscle was taken, the apparatus for the determination was connected with the nerve through the electrodes nearer the muscle. They were separated from the fatiguing electrodes by more than 3 centimeters, and ar- ranged so that the kathode was next the muscle. When the threshold of the muscle was taken direct- ly the apparatus was connected with the muscle through platinum needle electrodes thrust into it. The position of the secondary coil of the inducto- rium, in every case, was read by moving it away from the primary coil until the very smallest pos- sible contraction of the muscle was obtained. Four of these readings were made, one with tissue resist- ance, the others with 10,000, 20,000, and 30,000 ohms additional resistance in the secondary cir- cuit. Only break shocks were employed the make shocks were short-circuited. Immediately after the determination of the position of the sec- ondary coil, and before the electrodes were re- moved or disconnected, three readings of the tis- sue resistance were made. From these data four values for ft were calculated. The strength of the primary current for deter- mining the threshold of the nerve-muscle was usu- ally .01 ampere, but in a few cases .05 ampere was used. For normal muscle it was .05 ampere and for denervated muscle 1.0 ampere. The inducto- 114 BODILY CHANGES rium, which was used throughout, had a secondary resistance of 1400 ohms. This was added to the average tissue resistance in making corrections corrections were made also for core magnetiza- tion. THE LESSENING OF NEURO-MUSCULAR IRRITABILITY BY FATIGUE The threshold for the peroneus communis nerve in decerebrate animals varied from 0.319 to 2.9G units, with an average in sixteen experiments of 1.179.* This average is the same as that found by E. L. Porter 2 for the radial nerve in the spinal cat. For animals under urethane anesthesia a higher average was obtained. In these it varied from .644 to 7.05, or an average in ten experiments of 3.081. The threshold for the tibialis anticus muscle varied in the decerebrate animals from 6.75 units to 33.07, or an average in fifteen experiments of 18.8. Ten experiments were performed under ure- thane anesthesia and the threshold varied from 12.53 to 54.9, with an average of 29.84 ft units. From these results it is evident that anesthesia notably affects the threshold. E. L. Porter proved, by experiments carried on in the Harvard Physiological Laboratory, that the threshold of an undisturbed nerve-muscle remains * For the detailed data of these and other quantitative ex- periments, the reader should consult the tables in the original papers. FATIGUE AND ADRENIN 115 constant for hours, and his observation was con- firmed by Gruber (see Fig. 19). If, therefore, after fatigue, a change exists in the threshold, this change is necessarily the result of alterations set up by the fatigue process in the nerve-muscle or muscle. After fatigue the threshold of the nerve-muscle, in sixteen decerebrate animals, increased from an average of 1.179 to 3.34 an increase of 183 per cent. In ten animals under urethane anesthesia the threshold after fatigue increased from a nor- mal average of 3.08 to 9.408 an increase of 208 per cent. An equal increase in the threshold stimulus was obtained from the normal muscle directly. In de- cerebrate animals the normal threshold of 18.8 units was increased by fatigue to 69.54, or an in- crease of 274 per cent. With urethane anesthesia the threshold increased from 29.849 to 66.238, or an increase of 122 per cent. Fig. 18, plotted from the data of one of the many experiments, shows the relative heights of the threshold before and after fatigue. The corre- spondence of the two readings of the threshold, one from the nerve supplying the muscle and the other from the muscle directly, served as a check on the electrodes. The broken line in the figure repre- sents the threshold (in units) of the nerve-muscle, and the continuous line that of the muscle. The 116 BODILY CHANGES threshold values of the nerve-muscle have been magnified ten times in order to bring the two rec- ords close together. In this experiment the thresh- FIGUBE 18. A record plotted from the data of one experiment. The time intervals in minutes are registered on the abscissa; the value of the threshold in units is registered on the ordinate. The continuous line is the record of the muscle, the broken line that of the nerve-muscle. The values for the nerve-muscle have been magnified ten times, those for the muscle are normal. (1) Normal values of the threshold. (2) Fatigue thresholds after one hour's work, lifting 120 grams 240 times a minute. (3 and 4) The threshold after rest. old of the muscle after fatigue (i.e., at 2) is 167 per cent higher than the normal threshold (at 1), while that of the nerve-muscle after fatigue is 30.5 per cent higher than its normal. Evidently a direct relation exists between the duration of work and the increase of threshold. For instance, the threshold is higher after a muscle is fatigued for two hours than it is at the end of FATIGUE AND ADRENIN 117 the first hour. The relation between the work done and the threshold is not so clear. In some animals the thresholds were higher after 120 grams had been lifted 120 times a minute for 30 minutes than they were in others in which 200 grams had been lifted 240 times a minute for the same period. The muscle in the latter instances did almost four times as much work, yet the threshold was lower. The difference may be due to the general condi- tion of the animal. A few experiments were performed on animals in which the nerve supplying the muscle was cut seven to fourteen days previous to the experiment. The muscle, therefore, had within it no living norve fibres. The average normal threshold for the denervatod muscle in G animals was 61.28 units. As in the normal muscle, the percentage increase due to fatigue was large. THE SLOW RESTORATION OF FATIGUED MUSCLE TO NORMAL IRRITABILITY BY REST That rest decreases the fatigue threshold of both nerve-muscle and muscle can be seen in Fig. 18. The time taken for total recovery, however, is de- pendent upon the amount of work done, but this change, like that of fatigue, varies widely with different individuals. In some animals the thresh- old returned to normal in 15 minutes; in others, in which the same amount of work was done, it was 118 BODILY CHANGES still above normal even after 2 hours of rest. This may be due to the condition of the animals in some the metabolites are probably eliminated more rapidly than in others. There were also variations in the rate of restoration of the normal threshold when tested on the nerve and when tested on the muscle in the same animal. In Fig. 18 (at 3) the nerve-muscle returned to normal in 30 minutes, whereas the muscle (at 4) after an hour's rest had not returned to normal by a few ft units. This, however, is not typical of all nerve-muscles and muscles. The opposite condition that in which the muscle returned to normal before the nerve- muscle occurred in as many cases as did the con- dition just cited. The failure of the two tissues to alter uniformly in the same direction may be ex- plained as due to variations in the location of the electrodes when thrust into the muscle at different times (e. g., whether near nerve filaments or not). The results from observations made on the nerve are more likely to be uniform and reliable than are those from the muscle. The time required for the restoration of the threshold from fatigue to normal, in denervated muscles, is approximately the same as that for the normal muscle. FATIGUE AND ADRENIN 119 THE QUICK KESTORATION OP FATIGUED MUSCLE TO NORMAL IRRITABILITY BY ADRENIN The foregoing observations showed that fatigue raises the normal threshold of a muscle, on the av- erage, between 100 and 200 per cent (it may be in- creased more than 600 per cent) ; that this increase is dependent on the time the muscle works, but also varies with the animal ; that rest, 15 minutes to 2 hours, restores the normal irritability ; and that this recovery of the threshold depends upon the time given to rest, the duration of the work, and also upon the condition of the animal. The prob- lem which was next attacked by Gruber was that of learning whether the higher contractions of fa- tigued muscle after splanchnic stimulation could be attributed to any influence which adrenal secre- tion might have in restoring the normal irritability. To gain insight into the probabilities he tried first the effects of injecting slowly into the jugular vein physiological amounts of adrenin.* The normal threshold of the peroneus communis nerve varied in the animals used in this series of observations from 0.35 to 5.45 units, with an aver- age in nine experiments of 1.3, a figure close to the 1.179 found in the earlier series on the effect of fatigue. For the tibialis anticus muscle, in which the nerve-endings were intact, the threshold varied * The form of adrenin used in these and in other injections was fresh adrenalin made by Parke, Davis & Co. 120 BODILY . CHANGES from 6.75 to 49.3 units, with an average in the nine experiments of 22.2. This is slightly higher than that cited for this same muscle in the earlier series. By fatigue the threshold of the nerve-muscle was increased from an average of 1.3 to an average of 3.3 units, an increase of 154 per cent. The muscle increased from an average of 22.2 to an average of 59.6, an increase of K>9 per cont. After an injec- tion of 0.1 to 0.5 cubic centimeters of adrenin (1:100,000) the fatigue threshold was decreased ivithin five minutes in the nerve-muscle from an average of 3.3 to 1.8, a recovery of 75 per cent, and in the muscle from an average of 59. G to 42.4, a re- covery of 46 per cent. To prove that this effect of adrenin is a counteraction of flic effects of fatigue, Gruber determined the threshold for muscle and nerve-muscle in non-fatigued animals before and after adrenin injection. He found that in these cases no lowering of threshold occurred, a result in marked contrast with the pronounced and prompt lowering induced by this agent in muscles when fatigued. Figs. 19 and 20, plotted from the data of two of the experiments, show the relative heights of the threshold before and after an injection of adrenin. The close correspondence of the two readings of the threshold, one from the nerve supplying the muscle, the other from the muscle directly, served to show that there was no fault in the electrodes. FATIGUE AND ADEENIN 121 The continuous line in the Figures represents the threshold (in units) of the muscle, the broken line that of the nerve-muscle. The threshold of the nerve-muscle is magnified 100 times in Fig. 19 and 10 times in Fig. 20. In Fig. 19 (at 2 and 4) the threshold was taken after an intravenous injection of 0.1 and 0.2 cubic centimeter of adrenin respec- tively. These examples show that adrenin does not af- fect the threshold of the normal non-fatigued mus- cle when tested either on the muscle directly or on the nerve-muscle. In Fig. 19 (at 3) the observa- tion taken after two hours of rest illustrates the constancy of the threshold under these circum- stances. In Fig. 19 the normal threshold was increased by fatigue (at 5) the muscle had been pulling 120 times a minute for one hour on a spring hav- ing an initial tension of 120 grams from 30.0 to 51.G units, an increase of 72 per cent; and in the nerve-muscle from 0.62 to 0.89 units, an increase of 46 per cent. The threshold (at 6) was taken fire minutes after injecting 0.1 cubic centimeter of adrenin (1:100,000). The thresh- old of the muscle was lowered from 51.6 to 38.0 units, a recovery of 62 per cent; that of the nerve-muscle from 0.89 to 0.79 units, a recovery of 37 per cent. After another injection of 0.5 cubic centimeter of adrenin the thresholds (at 7) were 122 BODILY CHANGES taken ; that of the nerve-muscle dropped to normal 0.59 units a recovery of 100 per cent, and that 90 80 70 3:30 FIGURE 19. A record plotted from the data of one experiment. The time inter- vals in hours and minutes are represented on the abscissa; the values of the threshold in ft units are represented on the ordinate. The continuous line is the record of the muscle, the broken line that of the nerve- muscle. The nerve-muscle record is mag- nified 100 times; that of the muscle is nor- mal. (1) Normal threshold stimulus. (2) Threshold five minutes after an intraven- ous injection of 0. 1 cubic centimeter of ad- renin (1:100,000) without previous fatigue. (3) Threshold after a rest of two hours. (4) Threshold five minutes after an injec- tion of 0.2 cubic centimeter of adrenin (1:100,000) without previous fatigue. (5) Threshold after one hour's fatigue. The muscle contracted 120 times per minute against a spring having an initial tension of 120 grams. (6) Threshold five minutes after an injection (0.1 cubic centimeter) of adrenin (1:100,000). (7) Threshold five minutes after another injection of adrenin (0.5 cubic centimeter of a 1:100,000 solu- tion). of the muscle remained unaltered 26 per cent above its normal threshold. In Fig. 20 the threshold (at 5) was taken five FATIGUE &ND ADKENIN 123 minutes after an injection of 0.1 cubic centimeter of adrenin. The drop here was as large as that shown in Fig. 19. The threshold taken from the FIGURE 20. A record plotted from the data of one experiment. The time intervals in hours and minutes are registered on the abscissa; the values of the threshold in units are registered on the ordinate. The continuous line is the record of the muscle, the broken line that of the nerve-muscle. The record of the nerve- muscle is magnified ten times; that of the muscle is normal. (1) Normal threshold. (2) The threshold after one hour's fatigue. The muscle contracted 120 times per minute against a spring having an initial tension of 120 grams. (3 and 4) Thresh- olds after rest; after 60 minutes (3), and after 90 minutes (4). (5) Threshold five minutes after an injection of adrenin (0.1 cubic centimeter of a 1:100,000 solution). (6 and 7) Thresholds after rest; after 60 minutes (6), and after 90 minutes (7). muscle directly was lowered from 30.6 to 18 units, a recovery of 61 per cent; the nerve-muscle from 1.08 to 0.87 units, a recovery of 51 per cent. That this sudden decrease cannot be dueto rest is shown in the same Figure (at 3 and 4). These readings were made after 60 and 90 minutes' rest respective- ly. The sharp decline in the record (at 5) indi- cates distinctly the remarkable restorative influ- 124 BODILY CHANGES ence of adrenin in promptly lowering the high, fatigue threshold of neuro-muscular irritability. THE EVIDENCE THAT THE KESTORATIVE ACTION OF ADRENIN is SPECIFIC As stated in describing the effects of arterial blood pressure, an increase of pressure is capable of causing a decided lowering of the neuro-muscu- lar threshold after fatigue. Is it not possible that adrenin produces its beneficial effects by better- ing the circulation ? Nice and I had argued that the higher contrac- tions of fatigued muscle, that follow stimulation or injection of adrenin, could not be wholly due to improved blood flow through the muscle, for when by traction on the aorta or compression of the thorax arterial pressure in the hind legs was pre- vented from rising, splanchnic stimulation still caused a distinct improvement, the initial appear- ance of which coincided with the point in the blood- pressure curve at which evidence of adrenal secre- tion appeared. And, furthermore, the improve- ment was seen also when adrenin was given intra- venously in such weak solution (1:100,000) as to produce a fall instead of a rise of arterial pressure. Lyman and I had shown that this fall of pressure was due to a dilator effect of adrenin. Since the blood vessels of the fatigued muscle were dilated by severance of their nerves when the nerve trunk was FATIGUE AND ADBENIN 125 cut, and, besides, as previously stated (see p. 86), were being stimulated through their nerves at a rate favorable to relaxation, it seemed hardly prob- FIGURE 21. Top record, blood pressure with mercury manometer. Middle record, contractions of the tibialis anticus muscle 240 times per minute against a spring with an initial tension of 120 Drains. Bottom record (zero blood pressure)) injection of 0.4 cubic centimeter of adrcnin (1:100,- 000) . Time in half minutes. able that adronin could produce its beneficial effect by further dilation of the vessels and by consequent flushing of the muscle with an extra supply of blood, 3 The lowering of blood pressure had 126 BODILY CHANGES been proved to have no other effect than to impair the action of the muscle (see p. 103) . Although the chances were thus against an interpretation of the beneficial influence of adrenin through action on the circulation, it was thought desirable to test the possibility by comparing its effect with that of another vasodilator amyl nitrite. Figs. 21 and 22 are curves obtained from the left tibialis anticus muscle. The rate of stimulation was 240 times a minute. The muscle in Fig. 21 contracted against a spring having an initial tension of 120 grams, and that in Fig. 22 against an initial tension of 100 grams. In Fig. 21, at the point indicated on the base line, 0.4 cubic centimeter of adrenin (1:100,000) was in- jected into the left external jugular vein. There resulted a fall of 25 millimeters of mercury in the arterial pressure and a concurrent betterment of 15 per cent in the height of contraction, requiring two minutes and fifteen seconds of fatigue (about 540 contractions) before it returned to the former level. In Fig. 22, at the point indicated by the arrow, a solution of amyl nitrite was injected into the right external jugular vein. There resulted a fall of 70 millimeters of mercury in arterial pres- sure and a betterment of 4.1 per cent in the height of muscular contraction, requiring fifteen seconds of fatigue (about 60 contractions) to decrease the height of contraction to its former level. In FATIGUE AND ADUENIN 127 FIGURE 22. Top record, blood pressure with mercury manometer. Middle record, con- tractions of tibialis anticus mus- cle 240 per minute against a spring with an initial tension of 100 grams direct load. Bottom record (zero blood pressure), time in half minutes. The arrow indi- cates the point at which a solu- tion of amyl nitrite was injected. 128 BODILY CHANGES neither case did the blood pressure fall below the critical region (see p. 104).* Although the fall in arterial pressure caused by dilation of the vessels due to amyl nitrite was al- most three times as great as that produced by the adrenin,. yet the resultant betterment was only about one-fourth the percentage height and lasted but one-ninth the time. In all cases in which these solutions caused an equal fall in arterial pressure, adrenin caused higher contractions, whereas amyl nitrite caused no appreciable change. THE POINT OF ACTION OF ADRENIN IN MUSCLE From the evidence presented in the foregoing pages it is clear that adrenin somehow is able to bring about a rapid recovery of normal irritability of muscle after the irritability has been much less- ened by fatigue, and that the higher contractions of a fatigued muscle after an injection of adrenin are due, certainly in part, to some specific action of this substance and not wholly to its influence on the circulation. Some of the earlier investigators " x " In some cases after injection of amyl nitrite the normal blood pressure, which was high, dropped sharply to a point below the critical region. There resulted a primary increase in muscular contraction due to the betterment in circulation caused by the dilation of the vessels before the critical region was reached. During the time that the pressure was below the critical region the muscle contraction fell. As the blood pressure again rose to normal the muscle contraction in- creased comcidently. FATIGUE AND ADKENIN 129 of adrenal function, notably Albanese, 4 and also Abelous and Langlois, r> inferred from experi- ments on the removal of the glands that the role they played in the bodily economy was that of neu- tralizing, destroying or transforming toxic sub- stances produced in tlie organism as a result of muscular or nervous work. It seemed possible that the metabolites might have a checking or blocking influence at the junction of the nerve fibres with the muscle fibres, and might thus, like curare, lessen the efficiency of the nerve impulses. Radwanska's ob- servation 6 that the beneficial action of adrenin is far greater when the muscle is stimulated through its nerve than when stimulated directly, and Panel- la's discovery 7 that adrenin antagonizes the ef- fect of curare, were favorable to the viow that adrenin improves the contraction of fatigued mus- cle by lessening or removing a block established by accumulated metabolites. The high threshold of fatigued denervated mus- cle, however, Gruber found was quite as promptly lowered by adrenin as was that of normal muscles stimulated through their nerves. Fig. 23 shows that the height of contraction, also, of the fatigued muscle is increased when adrenin is administered. In this experiment the left tibialis anticus muscle was stimulated directly by thrusting platinum needle electrodes into it. The peroneus communis nerve supplying the muscle had been cut and two 130 BODILY CHANGES centimeters of it removed nine days previous to the experiment. The rate of stimulation was 120 times per minute and the initial tension of the spring about 120 grams. At the point indicated FIGURE 23. Top record, blood pressure with mercury manometer. Middle record, contractions of a denervated muscle (tibialis anticus) 240 per per minute against a spring having an initial ten- sion of 120 grams (peroneus comma nix nerve was cut nine days before this record was taken). Bot- tom record (zero blood pressure), time in half min- utes. At the point indicated by an arrow 0.1 cubic centimeter of adreniri (1:100,000) was injected intravenously. by the arrow an injection of 0.1 cubic centimeter of adrenin (1:100,000) was made into a jugular vein. A fall in arterial pressure from 110 to 86 millimeters of mercury and a simultaneous better- ment of 20 per cent in the height of contraction FATIGUE AND ADEENIN 131 were obtained. It required four minutes of fatigue (about 480 contractions) to restore the muscle curve to its former level. Eesults similar to this were obtained from animals in which the nerve had been cut 7, 9, 12, 14, and 21 days. In all instances the nerve was inexcitable to strong f aradic stimula- tion. In Kadwanska's experiments, mentioned above, the muscle was stimulated directly when the nerve endings were intact. It seems reasonable to sup- pose, therefore, that in all cases he was stimulat- ing nerve tissue. Since a muscle is more irritable when stimulated through its nerve than when stimulated directly (nerve and muscle), a slight change in the irritability of the muscle by adrenin would naturally result in a greater contraction when the nerve was stimulated. Panella's results also are not inconsistent with the interpretation that the effect of adrenin is on the muscle substance rather than on the nerve endings. A method which has long been used to separate muscle from nerve is that of blocking the nervous impulses by the drug curare. Gruber found that when curare is in- jected the threshold of the normal muscle is in- creased, as was to be expected from the removal of the highly efficient nervous stimulations. And also, as was to be expected on that basis, curare did not increase the threshold in a muscle in which the nerve endings had degenerated. Adrenin antago- 132 BODILY CHANGES nizes curare with great promptness, decreasing the heightened threshold of a curarized muscle, in five minutes or less, in some cases to normal. From this observation it might be supposed that curare and fatigue had the same effect, and that adrenin had the single action of opposing that effect. But fatigue raises the threshold of a curarized muscle, and adrenin then antagonizes this fatigue. Lang- ley 8 has argued that curare acts upon a hypo- thetical "receptive substance" in muscle. If so, probably curare acts upon a substance, or at a point, different from that upon which fatigue acts ; for, as the foregoing evidence shows, fatigue in- creases the threshold of a muscle whether deprived of its nerve supply by nerve section and degenera- tion or by curare, whereas curare affects only the threshold of a muscle in which the nerve endings are normal. 9 And since adrenin can oppose the effects of both curare and fatigue, it may be said to have two actions, or to act on two different substances or at two different points in the muscle. Gruber 10 has recently shown that adrenin per- fused through dying muscle, and through muscle rendered less efficient by the injection of fatigue products (lactic acid, and acid sodium and potas- sium phosphate), has a remarkable capacity to restore the contractile process after it has practic- ally disappeared, or to augment it greatly after it has been much reduced. FATIGUE AND ADRENIN 133 The evidence adduced in the last chapter indi- cated that the greater "head" of arterial pressure produced by the more rapid heart beat and the stronger contraction of many arterioles in times of great excitement would be highly serviceable to the organism in any extensive muscular activity which the excitement might involve. By assuring an abundant flow of blood through the enlarged ves- sels of the working muscle, the waste products resulting from the wear and tear in contraction would be promptly swept away and thus would be prevented from impairing the muscular effi- ciency. The adrenin discharge at stich times would, as was pointed out, probably reinforce the effects of sympathetic impulses. The evidence presented in this chapter shows that adrenin has also another action, a very remarkable action, that of restor- ing to a muscle its original ability to respond to stimulation, after that has been largely lost by continued activity through a long period. What rest will do only after an hour or more, adrenin will do in five minutes or less. The bearing of this striking phenomenon on the functions of the or- ganism in times of great need for muscular activ- ity will be considered in a later discussion. REFERENCES 1 Qruber: American Journal of Physiology, 1913, xxxii, p. 437. 2 E. L. Porter : ' American Journal of Physiology, 1912, xxxi, p. 149. 134 BODILY CHANGES- 3 Cannon and Nice: American Journal of Physiology, 1913, xxxii, p. 55. 4 Albanese : Archives Italiennes de Biologie, 1892, xvii, p. 239. 5 Abelous and Langlois : Archives de Physiologic, 1892, xxiv, pp. 269-278, 465-476. 6 Radw&nska: Anzeiger der Akademie, Krakau, 1910, pp. 728-736. Reviewed in the Centralblatt fur Biochemie und Biophysik, 1911, xi, p. 467. 7 Panella : Archives Italiennes de Biologie, 1907, xlvii, p. 30. 8 Langley: Proceedings of the Royal Society of London, 1906, Ixxviii, B, p. 181. Journal of Physiology, 1905-6, xxxiii, pp. 374-413. 9 See Gruber : American Journal of Physiology, 1914, xxxiv, p. 89. 10 Gruber: Ibid., 1918, xlvi, p. 472; 1918, xlvii, p. 178, 185. CHAPTER IX THE HASTENING OF COAGULATION OF BLOOD BY ADRENIN The primary value of blood to the body must have been one of the earliest observations of rea- soning beings. When we consider the variety of fundamental services which this circulating fluid performs the conveyance of food and oxygen to all the tissues, the removal of waste, the delivery of the internal secretions, the protection of the body against toxins and bacterial invasion, and the dis- tribution of heat from active to inactive regions the view of the ancient Hebrews that the "life of the flesh is in the blood" is well justified. It is naturally of the utmost importance that this pre- cious fluid shall be safeguarded against loss. And its property of turning to a jelly soon after escap- ing from its natural channels assures a closure of the opening through which the escape occurred, and thus protection of the body from further bleeding. The slight evidence that adrenin hastens the clot- ting process has already been hinted at. When we 135 136 BODILY CHANGES found that adrenin is set free in pain and intense emotion, it seemed possible that there might exist in the body an arrangement for making doubly sure the assurance against loss of blood, a proc- ess that might nicely play its role precisely when the greatest need for it would be likely to arise. It was in 1903, while tracing in dogs the rise and fall of sugar in the blood after administering adrenin, that Vosburgh and Richards 1 first noted that simultaneously with the increase of blood sugar there occurred more rapid coagulation. In some cases the diminution was as much as four- fifths the coagulation time of the control. Since this result was obtained by painting "adrenalin" on the pancreas, as well as by injecting it into the abdominal cavity, they concluded that "the phe- nomenon appears to be due to the application of adrenalin to the pancreas." Six years later, dur- ing a study of the effect of adrenalin on internal hemorrhage, "Wiggers 2 examined incidentally the evidence presented by Vosburgh and Richards, and after many tests on five dogs found "never the slightest indication that adrenalin, either when injected or added to the blood, appreciably hast- ened the coagulation process." In 1911 von den Velden 3 reported that adrenin (about 0.007 mil- ligram per kilo of body weight) decreased the coagulation time in man about one-half an effect appearing 11 minutes after administration by FASTER COAGULATION BY ADEENIN 137 mouth, and 85 minutes after subcutaneous injec- tion. He affirmed also, but without describing the conditions or giving figures, that adrenin de- creases coagulation time in vitro. He. did not at- tribute the coagulative effect of adrenin in patients to this direct action on the blood, however, but to vasoconstriction disturbing the normal circulation and thereby the normal equilibrium between blood and tissue. In consequence, the tissue juices with their coagulative properties enter the blood, so he assumed. In support of this theory he offered his observation that coagulation time is decreased after the nasal mucosa has been rendered anemic by adrenin pledgets. Von den Velden's claim 3 for adrenin given by mouth was subjected to a single test on man by Dale and Laidlaw, 4 but their re- sult was completely negative. The importance of Vosburgh and Richards' ob- servation, the thoroughly discordant testimony of later investigators, as well as the meager and inci- dental nature of all the evidence that has been ad- duced either for or against the acceleration of clot- ting by adrenin, made desirable a further study of this matter. Especially was this further study de- sirable because of the discharge of adrenin into the blood in pain and emotional excitement. Ac- cordingly, in 1914, H. Gray and 1 5 undertook an investigation of the question. In doing so we em- ployed cats as subjects. Usually they were quickly 138 BODILY CHANGES decerebrated under ether, and then continuance of the drug became unnecessary. Body temperature was maintained by means of an electric heating pad. Eespiration proceeded normally except in a few instances (in which, presumably, there was hemorrhage into the medulla), when artificial res- piration had to be given. THE GRAPHIC METHOD OP MEASURING THE COAGULATION TIME In order to avoid, so far as possible, the personal element in determining when the blood was clotted, FIGURE 24. Diagram of the graphic coagulometer. The can- nula at the right rests in a water oath not shown in this diagram. For further description see text. the blood was made to record its own clotting. The instrument by means of which this was done was the graphic coagulometer devised by W. L. Men- denhall and myself, 6 and illustrated diagram- matically in Fig. 24. It consists essentially of a light aluminum lever with the long arm nearly counterpoised by a weight W. The long arm is FASTER COAGULATION BY ADRENIN 139 prevented from falling by a support S, and is pre- vented from rising by. a horizontal right-angled rod reaching over the lever at R l and fixed into the block B which turns on the axis A. Into the same block is fixed the vertical rod R 2 . When this rod is moved from the post P 1 , against which it is held by the weight of the horizontal rod fl 1 , towards the other post P 2 , the check on the long arm of the lever is lifted, and if the short arm is heavier, the long arm will then rise. The cannula C, into which the blood is received, is two centimeters in total length and slightly more than two millimeters in internal diameter. It is attached by a short piece of rubber tubing to the tapered glass tube T, five centimeters long and five millimeters in internal diameter. The upper end of this tube is surrounded by another piece of rub- ber which supports the tube when it is slid into the U-shaped support 7, fixed directly below the end of the short arm of the lever. By drawing the cannulas from a single piece of glass tubing and by making the distance from shoulder to upper end about twelve millimeters, receptacles of fairly uniform capacity are assured. All the dimensions, the reach of the rubber con- nection over the top of the cannula (2-3 milli- meters), the distance of the upper rubber ring from the lower end of the glass chamber (4 centi- meters), etc., were as nearly standard as possible. 140 BODILY CHANGES A copper wire D, eight centimeters long and 0.6 millimeters in diameter, -bent above into a hook and below into a small ring slightly less than two millimeters in diameter, is hung in a depression at the end of the short arm of the lever. The small ring then rests in the upper part of the 'cannula (see Fig. 24). The weight of the copper wire makes the short arm of the lever heavier than the long arm by 30 milligrams, when the delicate writ- ing point is moving over a lightly smoked drum. Half a dozen of these standard wires are needed. For accurate determination of the coagulation time Addis 7 has defined the following conditions as essential: 1. The blood must always be obtained under the same conditions. 2. Estimates must all be made at the same tem- perature. 3. The blood must always come in contact with the same amount and kind of foreign material. 4. The end point must be clear and definite and must always indicate the same degree of coagula- tion. The precautions taken to fulfill these conditions were as follows : 1. Dr diving the blood. The blood was taken from the femoral artery. The artery (usually the right) was laid bare in the groin and freed from surrounding tissue. A narrow artery clip, with FASTER COAGULATION BY ADRENIN 141 each limb enclosed in soft rubber tubing (to pre- vent injury of the tissues), and with its spring ex- erting gentle pressure, was placed on the artery immediately below the deep femoral branch, thus allowing no blood to stagnate above the clip. Be- tween the clip and a ligature applied about 1.5 centimeters below, an opening was made. The blood was carefully milked out of the vessels be- tween a blunt dissector moved beneath, and a small forceps, twisted into a pinch of absorbent cotton, moved above. The cannula, cleaned in water, alcohol, and ether, was set in the rubber connection of the glass tube ; the point of the cannula was then lubricated with vaseline and slipped into the artery. The pres- sure of the clip on the artery was next very slightly released and blood was allowed to flow into the cannula up to the lower border of the rubber con- nection. Only a good-sized drop of blood was needed. Sometimes the blood ran one or two milli- meters above or below, but without appreciably changing the result. Since the clip was situated on the femoral immediately below a branch in which the circulation persisted, the blood received in the cannula was always fresh from the moving stream. As soon as the clip gripped the artery again, the cannula was slipped out. A helper then promptly milked the vessel in the manner described above, and covered it with a pad of absorbent cotton 142 BODILY CHANGES smeared with vaseline to prevent drying. There- by blood was not permitted to stagnate ; and when a new sample was to be taken, the vessel was clean and ready for use. The tip of the cannula was at once plugged by plunging it into a flat mound of plasticine about three millimeters high. It was drawn off sidewise lest the plasticine plug be pulled out again. One of the copper wires D was now slid into the tube and cannula, the tube slipped into the U-support, and the wire lifted and hung on the lever. This procedure, from the moment blood began to flow until the wire was hung, consumed usually about twenty seconds. 2. Uniform temperature. Under the U-support was placed a large water bath, in which the can- nula and the tapering part of the tube were sub- merged. A thermometer was fixed to the U-sup- port so that the bulb came near the cannula in the bath. The water was kept within a degree of 25 C. This temperature was chosen for several rea- sons: (a) The cannula has room temperature and rapidly cools the small volume of blood that enters it. To heat blood and cannula to body tempera- ture would take time. A bath near room tempera- ture, therefore, seems preferable to one near body temperature, (b) The test of clotting was conveni- ently made at intervals of a half -minute, and if the clotting process were hastened by higher tempera- FASTER COAGULATION BY ADEENIN 143 tures, this interval would become relatively less exact, (c) A temperature of 25 C. rather than lower was selected because, as Dale and Laidlaw 8 have shown, the coagulation time is much slower for a given change in temperature below 25 than for the same change above. And with slow- ing of the process the end point, when the determin- ation depends on supporting a weight, is less likely to be sharp, (d) The researches undertaken with use of this coagulometer were concerned with fac- tors hastening the process. For that reason and for reason (b), a long rather than a short coagula- tion time for normal conditions was desirable. 3. Uniformity in the amount and kind of con- tact with foreign surface. The capacity of the can- nulas was fairly uniform, as stated above; the amount received in them was fairly constant ; and the wire hanging in the blood presented approxi- mately the same surface in different observations. A further condition for insuring consistent treat- ment of the blood in different cases was that of making the tests for coagulation always at the same intervals. Below the writing point of the lever was set an electromagnetic signal E, which recorded half-minutes. At the moment a record was made by the signal (see first signal mark, Fig. 25) the clip on the artery was opened, the blood taken, and the process thus begun. In about 20 seconds the cannula was suspended in the water 144 BODILY CHANGES FASTER COAGULATION BY ADEENIN 145 bath and the wire was hanging on the lever. At the next record by the signal and at every subsequent record the vertical rod R 2 was pushed with the index finger from post P l to post P 2 and allowed to move back. This motion was uniform and lasted about one second. The check R l on the long arm of the lever was thus raised, and as the wire sank in the blood the writing point rose, recording that coagulation had not taken place (see Fig. 25). 4. Definite end point. As soon as the blood clot- ted, the weight of 30 milligrams was supported, and the failure of the lever to rise to the former height in the regular time allowed, recorded that the change had occurred. Very rarely the swing of the lever would be checked for a moment and would then begin to move rapidly, indicating that a strand of fibrin had formed but not sufficiently strong to support the weight, and that when the strand broke, the weight quickly sank in the blood. If this occurred, the next record almost always was the short line, which signified that the weight was well supported. A very slight strand of fibrin was able to pre- vent the weight from dropping, though at different times the amount of support differed, as shown by the varying length of the final lines (compare first and last series, Fig. 25). These variations are probably a rough indication of the degree of coagu- lation. In our experiments, however, the length of 146 BODILY CHANGES the final line was disregarded, and merely the fact that the lever .failed to swing through its usual distance was taken as evidence of a clot, and the consequent short record was taken as the end point. As soon as this end point was registered, the tube, wire and cannula were lifted out of the bath ; the cannula was then separated from the tube and pulled away from the wire. The clot was thus dis- closed, confirming the graphic record. The method, at least when used at half -minute intervals, did not reveal in all instances the same degree of clotting. Usually, when the process was very rapid, the revealed clot was a thick jelly; whereas, when the process was slow, a strand of fibrin or at most a small amount of jelly was found. This difference in the degree of coagulation intro- duced, of course, an element of inexactness. In our experiments, however, this inexactness was unfa- vorable to the result we were seeking for, i. e., the acceleration of the process because the jelly is a later stage than the fibrin strand; and since we nevertheless obtained good evidence of accelera- tion, we did not in these experiments attempt to determine more accurately differences in the stage of the clotting process, 5. Cleaning of apparatus. After the wire was removed from the tube, the clot attached to its ring-tip was carefully brushed away under cool running water. Under the running water, also, a FASTER COAGULATION BY ADBENIN 147 trimmed feather was introduced into the cannula and the tube to push out the plasticine and to wash out the blood. Wire, cannula and tube were then dropped into a beaker receiving running hot water (about 80 C.) and there allowed to remain for about five minutes. On removal from this the parts were shaken free from water, passed through 95 per cent alcohol and again shaken free, passed through ether and let dry. By having a half-dozen cannulas and wires of standard size, it was possible to save trouble by cleaning a number at one time. Not infrequently the first few samples of blood taken from an animal showed rapid or somewhat irregular rates of clotting. Some causes for these initial variations will be presented in following pages. The fairly uniform rate of clotting in any individual after the initial stage, varied in twenty- one different animals from an average of 3 to an average of 10.6 minutes, with a combined average of 5.9 minutes. The conditions for these variations among the individuals have not been wholly deter- mined. THE EFFECTS OF SUBCUTANEOUS INJECTIONS OF ADRENIN The first observations were of this class. Oct. 27. A cat weighing about 3 kilos was given 3 cubic centimeters of adrenin 1 :1,000, i.e., 1 milli- gram per kilo, under the skin. The animal, in this 148 BODILY CHANGES instance, was kept in uniform ether anesthesia. Following is a record showing when blood was taken, and the coagulation time in each instance : 2.56 Injection made 3.27 3.5 minutes .59 6 minutes .44 2 " 3.075.5 " .552.5 .135 " 4.073 " .206.5 " .202 " Average 5.7 minutes Average 2.6 minutes 4.44 6 minutes ' 5.004.5 5.505 " Average 5.2 minutes In this case the coagulation time remained at its usual level for about 20 minutes after the subcu- taneous injection.* Thereafter for about an hour the coagulation time averaged 45 per cent of its previous duration. And widely separated tests made during the following hour indicated that ap- proximately the initial rate of clotting had been re- gained. The rather long period (nearly 30 minutes), in the case just cited, between the injection and the * This period is longer than is expected after the subcuta- neous injection of any drug. As will be shown later, strong doses of adrenin, if injected rapidly, may not at first shorten the clotting process. Probably in some instances of subcu- taneous injection of these strong doses, the drug enters the circulation more rapidly than in others and in consequence coagulation is not at first accelerated. FASTER COAGULATION BY ADRENIN 149 first appearance of rapid clotting was not the rule. As the following figures show, the coagulation time may become shortened quite promptly after sub- cutaneous injection. Oct. 29. 3.30 5.5 minutes 3.53 4 minutes .365.5 " 4.013.5 " .44 Adrenin, 3 cu- .083.5 " bic centimeters, .16 4.5 " 1:1,000, injected .235 " subcutaneously. .30 5.5 " .46 5.5 minutes In this case nine minutes after the injection the change in the rate of clotting had begun, and it con- tinued more rapid for the subsequent half -hour. We did not attempt to find the- minimal subcu- taneous dose which would shorten clotting. A dose of 0.01 milligram per kilo, however, has proved effective, as shown by the following figures : Feb. 3. 11.3410 minutes .5510 minutes .45 9 " 12 .06 7 " .50 to .52 Adrenin, .14 4 " 2.8 cubic centimeters, .19 5.5 " 1 :100,000, injected under .31 6 " skin of groin in cat .37 7 " weighing 2.8 kilos. :45 9 " As will be shown later, the dose in this instance was ten times the minimal effective intravenous dose. On the basis of these figures, less than a milligram of adrenin given subcutaneously would be necessary to shorten clotting to a marked degree in a man of average weight (70 kilograms). 150 BODILY CHANGES Not many observations were made by us on the effects of adrenin administered subcutaneously. The amount reaching the vascular system and the rate of its entrance into the blood could be so much more accurately controlled by intravenous than by subcutaneous introduction that most of our atten- tion was devoted to the former method. THE EFFECTS OF INTRAVENOUS INJECTIONS In this procedure a glass cannula was fastened in one of the external jugular veins and filled with the same solution as that to be injected. A short rubber tube was attached and tightly clamped close to the glass. Later, for the injection, the syringe needle was inserted through the rubber and into the fluid in the cannula, the clip on the vein was removed, and the injection made. The solutions employed intravenously were adrenin 1 :10,000, 1 :50,000, and 1 :100,000, in dis- tilled water. The smallest amount which produced any change in clotting time was 0.1 cubic centimeter of a dilu- tion of 1 :100,000 in a cat weighing two kilos, a dose of 0.0005 milligram per kilo. Four tests previous to the injection averaged 5 minutes, and none was shorter than 4 minutes. Immediately after the in- jection the time was 2 minutes, but at the next test the effect had disappeared. Doubling the dose in the same cat i. e., giving 0.2 cubic centi- FASTER COAGULATION BY ADEENIN 151 meter (0.001 milligram per kilo) shortened the coagulation time for about 40 minutes : Dec. 23. 10 .30 4 minutes 10 .53 3.5 minutes .354 " 11.001.5 " .414 " .051.5 .46 Adrenin, 0.001 .103 " milligram per .15 2 " kilo. .204 .472.5 minutes .264.5 " .503 " .315 " From 10.47, immediately after the second injec- tion, till 11.20 the average time for clotting was 2.5 minutes, whereas both before and after this period the time was 4 minutes or longer. At 11.00 o'clock and 11.05, when the end point was reached in 1.5 minutes ( a reduction of 63 per cent), a thick jelly was found on examining the cannula. The changes in clotting time in this case are represented graph- ically in Fig. 26. In another case a dose of 0.0005 milligram per kilo failed to produce any change, but 0.001 milli- gram per kilo (0.28 cubic centimeter of adrenin, 1 :100,000, given a cat weighing 2.8 kilos) brought a sharp decline in the record, as follows : Jan. 9. 11.326 minutes 11.485.5 minutes .406 " ,55-^ " .47 Adrenin, 0.001 12.005.5 milligram per .06 7 " kilo. In these instances the animals were decere- brated. For decerebrate cats, the least amount of 152 BODILY CHANGES adrenin, intravenously, needed to produce shorten- ing of coagulation time is approximately 0.001 milligram per kilo. In the above cases rapid clotting was manifest directly after minute doses. Larger doses, how- i i i j 10:80 :40 :50 11:00 :20 :SO FIGURE 26. Shortening of coagulation time after injection of adrenin, 0.2 cubic centimeter, 1:100,000, (0.001 milligram per kilo), at 10:46. In this and following Fig- ures a scale for coagulation time is given in minutes at the left. ever, may produce primarily not faster clotting but slower, and that may be followed in turn by a much shorter coagulation time. The figures below pre- sent such an instance : Nov. 25. 2 .363 minutes .403 " .43 Adrenin, 0.5 cubic centime- ter, 1:10,000. .44 4 minutes .493.5 .531.5 " ;.65 1.5 .582 " 3.002.5 minutes .031.5 " 051.5 " .072.5 " .101.5 .141.5 .162.5 193 " .233 " .303 FASTEK COAGULATION BY ADEENIN 153 This unexpected primary increase of coagula- tion time, lasting at least six minutes, is in strik- ing contrast to the later remarkable shortening of the process from 3 to an average of 1.7 minutes for more than 20 minutes (see Fig. 27, A). If a strong solution, i. e., 1 :10,000, is injected rapidly, the process may be prolonged as above, but not followed as above by shortening, thus : Nov. 28. 9 .593 minutes 10 .143.5 minutes 10.033 " .183.5 " .08 Adrenin, 0.5 .223.5 " cubic centi- .263 " meter, 1:10,- .293 " 000. .333 " .10 3 minutes There was in this case no decrease in coagulation time at any test for a half -hour after the injection, but instead a lengthening (see Fig. 27, B). How- ell 9 has reported the interesting observation that repeated massive doses of adrenin given to dogs may so greatly retard coagulation that the animals may be said to be hemophilic. These two instances show that on coagulation large doses have the contrary effect to small, just as Hoskins 10 showed was true for intestinal and Lyman and I n showed was true for arterial smooth muscle. In a few experiments the brain and the cord to midthorax were destroyed through the orbit. Arti- ficial respiration then maintained the animal in uni- 154 BODILY CHANGES form condition. Under these circumstances, adre- nin intravenously had more lasting effects than when given to the usual decerebrate animals with intact cord. Fig. 28 illustrates such a case. For thirty minutes before injection the clotting time averaged 5.4 minutes. Then, about ten minutes after one cubic centimeter of adrenin, 1 :50,000, had I I I I *:40 :50 9:00 :10 :20 :80 10:00 :10 :20 ;30 FIGURE 27. A, Primary lengthening followed by shortening of the coagulation time when adrenin, 0.5 cubic centimeter 1:10,000 (0.05 milligram), was injected slowly at 2 :43. B, Lengthening of the coagulation time without shortening when the same dose was injected rapidly at 10:08. been slowly injected, clotting began to quicken; during the next twenty minutes the average was 3.4 minutes, and during the following forty-five min- utes the average was 1.9 minutes only C5 per cent as long as it had been before the injection. In another case in which the brain and upper cord were similarly destroyed, the clotting time, which for a half -hour had averaged 3.9 minutes, was reduced by one cubic centimeter of adrenin, FASTER COAGULATION BY ADEENIN 155 1 :100,000, to an average for the next hour and forty minutes of 2.3 minutes, with 1.5 and 3 minutes as extremes. During the first forty minutes of this period of one hour and forty minutes of rapid clot- ting all of eight tests except two showed a coagula- tion time of 2 minutes or less. The explanation of this persistent rapid clotting in animals with spinal cord pithed is not yet clear. As indicated in Figs. 26, 27 and 28, the records of coagulation show oscillations. Some of these ups and downs are, of course, within the limits of 1 I I I I lilt 10:40 :50 11:00 :10 .-20 :SO :40 :50 12:00 :10 :20 FIGURE 28. Persistent shortening of the coagulation time after injecting (in an animal with brain and upper cord pithed) adrenin, 1 cubic centimeter, 1:50,000 (0.02 milligram), at 11:01-02. The dash lines represent averages. error of the method, but in our experience they have occurred so characteristically after injection of adrenin, and so often have appeared in a rough 156 BODILY CHANGES rhythm, that they have given the impression of be- ing real accompaniments of faster clotting. It may be that two factors are operating, one tending to hasten, the other to retard the process, and that the equilibrium disturbed by adrenin is recovered only after interaction to and fro between the two factors. The oscillations in coagulation time after the in- jections suggest that clotting might vary with changes in blood pressure, for that also commonly oscillates after a dose of adrenin (see, e.g., Fig. 23). Simultaneous recording of blood pressure and determining of coagulation time have revealed that each may vary without corresponding varia- tion in the other. Within ordinary limits, there- fore, changes of blood pressure do not change the rate of clotting. THE HASTENING OF COAGULATION BY ADRENIN NOT A DIRECT EFFECT ON THE BLOOD As previously stated, von den Velden has con- tended that shortening of coagulation time by adre- nin is due to exudation of tissue juices resulting from vasoconstriction. The amount of adrenin which produces markedly faster clotting in the cat, is approximately 0.001 milligram per kilo. As Lyman and 1 12 showed, however, this amount when injected slowly, as in the present experi- ments, results in brief vasodilation rather than FASTEE COAGULATION BY ADEENIN 157 vasoconstriction. Von den Velden's explanation can therefore not be applied to these experiments. He has claimed, furthermore, that adrenin added to blood in vitro makes it clot more rapidly, but, as already noted, he gives no account of the condi- tions of his experiments and no figures. It is im- possible, therefore, to criticise them. His claim, however, is contrary to Wiggers's 13 earlier ob- servations that blood with added adrenin coagulat- ed no more quickly than blood with an equal amount of added physiological salt solution. Also contrary to this claim are the following two experi- ments: (1) Ligatures were tied around the aorta and inferior vena cava immediately above the dia- phragm, and thus the circulation was confined al- most completely to the anterior part of the animal. Indeed, since the posterior part ceases to function in the absence of blood supply, the preparation may be called an "anterior animal." When such a preparation was made and 0.5 cubic centimeter of adrenin, 1:100,000 (half the usual dose, because, roughly, half an animal), was injected slowly into one of the jugulars, coagulation was not shortened. "Whereas for a half -hour before the injection the clotting time averaged 4.6 minutes, for an hour thereafter the average was 5.3 minutes a pro- longation which may have been due, not to any in- fluence of adrenin, but to failure of the blood to circulate through the intestines and liver. 14 In an- 158 BODILY CHANGES other experiment after the gastro-intestinal canal and liver had been removed from the animal, the average time for coagulation during twenty-five minutes before injecting adrenin (0.23 cubic centi- meter, 1 :100,000, in an animal weighing originally 2.3 kilos) was 5.5 minutes, and during forty min- utes after the injection it was 6.8 minutes, with no case shorter than 6 minutes. In the absence of cir- culation through the abdominal viscera, therefore, adrenin fails to shorten the clotting time. (2) The cannulas were filled with adrenin, 1:1,000, and emptied just befpre being introduced into the artery. The small amount of adrenin left on the walls was thus automatically mixed with the drawn blood. Alternate observations with these cannulas wet by adrenin and with the usual dry cannulas showed no noteworthy distinction. Feb. 19. 2.21 6 minutes, with usual cannula .306.5 " " " " .366.5 " " adrenin " .567 " " usual " 3.046 " adrenin The results of these experiments have made it impossible for us to concede either of von den Velden's claims, i. e., that clotting occurs faster be- cause adrenin is added to the blood, or because adrenin by producing vasoconstriction causes tis- sues to exude coagulant juices. Vosburgh and Richards found that coagulation FASTEE COAGULATION BY ADEENIN 159 became more rapid as the blood sugar increased. Conceivably faster clotting might result from this higher percentage of blood sugar. Against this assumption, however, is the fact that clotting is greatly accelerated by 0.001 milligram adrenin per kilo of body weight, much less than the dose necessary to increase the sugar content of the blood. 15 And furthermore, when dextrose (3 cubic centimeters of a 10 per cent solution) is added to the blood of an anterior animal, making the blood sugar roughly 0.3 per cent, the coagulation time is not markedly reduced. Adrenin appears to act, therefore, in some other way than by increasing blood sugar. Since adrenin makes the blood clot much faster than normally in the intact animal, and fails to have this effect when the circulation is confined to the anterior animal, the inference is justified that in the small doses here employed adrenin produces its remarkable effects, not directly on the blood it- self, not through change in the extensive neuro- muscular, bony, or surface tissues of the body, but through some organ in the abdomen. That exclusion of the liver from the bodily econ- omy, by ligature of its vessels or by phosphorus poisoning, will result in great lengthening of the coagulation time has been clearly shown. The liver, therefore, seems to furnish continuously to the blood a factor in the clotting process which is 160 BODILY CHANGES being continuously destroyed in the body. It is not unlikely that adrenin makes the blood clot more rapidly by stimulating the liver to discharge this factor in greater abundance. But proof for this suggestion has not yet been established. KEFEKENCES I Voshurgh and Richards : American Journal of Physi- ology, 1903, ix, p. 39. 2 Wiggers: Archives of Internal Medicine, 1909, iii, p. 152. 3 Von den Velden : Miinchener medizinische Wochen- schrift, 1911, Iviii, p. 1ST. 4 Dale and Laidlaw: Journal of Pathology and Bacteriol- ogy, 1912, xvi, p. 362. 5 Cannon and Gray : American Journal of Physiology, 1914, xxxiv, p. 321. 6 Cannon and Mendenhall : American Journal of Physi- ology, 1914, xxxiv, p. 225. 7 Addis : Quarterly Journal of Experimental Physiology, 1908, i, p. 314. 8 Dale and Laidlaw : Loc. cit., p. 359. 9 Howell : American Journal of Physiology, 1914, xxxiii, p. xiv. 10 Hoskins : American Journal of Physiology, 1912, xxix, p. 365. II Cannon and Lyman : American Journal of Physiology, 1913, xxxi, p. 376. 12 Cannon and Lyman : Loc. cit., p. 381. 18 Wiggers: Loc. cit., p. 152. 14 See Pawlow : Archiv f iir Physiologie, 1887, p. 458. Bohr: Centralblatt fiir Physiologie, 1888, ii, p. 263. Meeki American Journal of Physiology, 1912, xxx, p. 173. Gray and Lunt: Hid., 1914, xxxiv, p. 332. "Cannon: American Journal of Physiology, 1914, xxxiii, p. 396. CHAPTEE X THE HASTENING OF THE COAGULATION OF BLOOD IN PAIN AND GKEAT EMOTION In the foregoing chapter evidence was presented that the intravenous injection of minute amounts of adrenin hastens the clotting of blood. The amounts used did not vary much above or below the amounts discharged by the adrenal glands after brief stimulation of the splanchnic nerves, as found by H. Osgood in the Harvard Laboratory, and may therefore be regarded as physiological. Since injected adrenin is capable of shortening the coagulation time, may not the increased secretion of the adrenals likewise have that effect? The an- swer to this question was the object of an investi- gation by W. L. Mendenhall and myself. 1 The blood was taken and its coagulation was re- corded graphically in the manner already de- scribed. In some instances the cats were etherized, in others they were anesthetized with urethane, or were decerebrated. The splanchnic nerves always were stimulated after being cut away from connec- 161 162 BODILY CHANGES tion with, the spinal cord. Sometimes the nerves were isolated unilaterally in the abdomen; some- times, in order to avoid manipulation of the abdom- inal viscera, they were isolated in the thorax and stimulated singly or together, A tetanizing cur- rent was used, barely perceptible on the tongue and too weak to cause by spreading any contrac- tion of skeletal muscles. COAGULATION HASTENED BY SPLANCHNIC STIMULATION That splanchnic stimulation accelerates the clot- ting of blood, and that the effects vary in different animals, are facts illustrated in the following cases : Oct. 25. A cat was etherized and maintained in uniform ether anesthesia. After forty minutes of preliminary observation the left splanchnic nerves were stimulated in the abdomen. Following are the figures which show the effects on the coagula- tion time: 3.00 4 minutes .03 2.5 minutes .075.5 " .072.5 .14^-4 " .113 " .324.5 " .162 " .39 to .40 Stimulation .201.5 " of left splanchnic. .23 4 " .425 minutes .295.5 " .495 " .405.5 .562 " .605 " 4.001 FASTER COAGULATION IN EMOTION 163 In this instance at least ten minutes elapsed be- tween the end of stimulation and the beginning of faster clotting. The period of faster clotting, how- ever, lasted for about a half -hour, during which the coagulation time averaged 2.1 minutes, only forty- three per cent of the previous average of 4.8 min- utes. It is noteworthy that the curve (see Fig. 29), i i i i 3:30 :40 :50 4:00 :SO :40 FIGURE 29. Shortening of coagulation time after stimulation of the left splanchnic nerves, 3:39-:40. while lower, shows oscillations not unlike those which follow injection of adrenin (see p. 155). The primary delay of the effect is not always, indeed it is not commonly, present : Nov. 6. A cat was anesthetized (1.40 p.m.) with urethane, and later (3.05) its brain was pithed. The following observations on the coagu- lation time show the prompt effect of splanchnic stimulation : 164 BODILY CHANGES 3 .36 7 minutes .466 " 4 .02 to .05 Stimulation of left splanchnic in abdomen. .08 4 minutes .103 " .183.5 " .236.5 " In Fig. 30 is presented the original record of the shortening of the coagulation after stimulation of the left splanchnic nerve (Nov. 8) in a cat with brain pithed. In the foregoing instances the coagulation time was reduced after splanchnic stimulation to less than half what it was before. The reduction was not always so pronounced. Nov. 7. A cat* maintained in uniform ether anesthesia with artificial respiration had the fol- lowing changes in the clotting time of its blood as the result of stimulating the left splanchnic nerve in the thorax : 3.40 5 minutes 4.06 3.5 minutes .455 " .114 .515.5 " .163.5 . 58 to 4 . 00 Stimulation of .214 left splanch- .26 4.5 nic. .315 4.01 15 minutes .366.5 In this case the average for about fifteen minutes before stimulation was slightly over five minutes, * This animal had just passed through a period of excite- ment with rapid clotting. FASTER COAGULATION IN EMOTION 166 coco 166 BODILY CHANGES and for twenty-five minutes thereafter it was four minutes. In all cases thus far the period of shortened coagulation lasted from ten to thirty minutes. In other cases, however, the effect was seen only in a single observation. If this had occurred only once after splanchnic stimulation, it might be attributed to accident, but it was not an infrequent result, e. g.: Oct. 28. A cat was etherized and decerebrated, and the splanchnic nerves were isolated in the thorax. Following are two instances of brief short- ening of coagulation after splanchnic stimulation : 3.36 4.5 minutes 4.07 4.5 minutes .424.5 " .125.5 " .47 to .49 Splanchnic stim- . 19 to .22 Splanchnic stim- ulation, ulation. .51 4.5 minutes .23 3.5 minutes .572 .27-^ 4.014 .335 " In the foregoing instance it is noteworthy that the degree of acceleration is not so great after the second stimulation of the splanchnics as it was after the first. This reduction of effect as the nerves were repeatedly stimulated was frequently noted. The following case presents another illus- tration : Nov. 12. A cat was etherized (2.35 p.m.) and the medulla was punctured (piqure) at 3.12. The FASTEE COAGULATION IN EMOTION 167 operation was without effect. The loss or lessen- ing of effectiveness on second stimulation of the left splanchnic nerves is to be compared with the persistence of effectiveness on the right side : 3.40 4.5 minutes 4.34 4 minutes .454.5 " .394 " .54 to .56 Stimulation of .444 " left splanchnic .48 4 " in abdomen. .55 to .57 Stimulation of 4.00 3 minutes right splanch- .052 " nic. .105.5 " .593 minutes .165 " 5.022.5 " .22 to .27 Stimulation of .073 " left ^splanchnic .113 " in abdomen. .15 5.5 " .304 minutes .225.5 " The experiments above recorded show that stimulation of the splanchnic nerves results imme- diately, or after a brief period, in a shortening of the coagulation time of the blood an effect which in different animals varies in duration and intens- ity, and diminishes as the stimulation is repeated. The next question was whether this effect is pro- duced through the adrenal glands. COAGULATION NOT HASTENED BY SPLANCHNIC STIMULATION IP THE ADRENAL GLANDS ARE ABSENT The manner in which splanchnic stimulation pro- duces its effects is indicated in the following ex- periments : Nov. 28. A cat was etherized, and through the 168 BODILY CHANGES orbit the central nervous system was destroyed to the midthorax. The blood vessels of the left adre- nal gland were then quickly tied and the gland removed. The readings for a half hour before the left splanchnic nerve was stimulated averaged seven minutes, then 4.38 to .40 Stimulation of left splanchnic (glandless). .42 7 minutes .507 5.02 to .04 Stimulation of right splanchnic. .06 4 minutes .107 .187 " .267 " Dec. 4. A cat was etherized and pithed through the orbit to the neck region. The right and left splanchnic nerves were tied and cut in the thorax. The left adrenal gland was then carefully removed. These operations consumed about a half-hour. The following records show the effect of stimulating the left and right splanchnic nerves : 4.10 5 minutes 5.00 2.5 minutes .164.5 " .146 " .25 to .28 Stimulation of .23 to .25 Stimulation of left splanchnic right splanch- (glandless). nic. .30 4.5 minutes .26 6 minutes .354.5 " .334.5 " .407.5 " .383.5 " .49 to .51 Stimulation of .434.5 " right splanch- .49 5 " nic. .556 " .564.5 minutes FASTER COAGULATION IN EMOTION 169 The results in this experiment are represented graphically in Fig. 31. I I I I I I I I I I 4:10 :20 :30 :40 :60 5:00 :10 :20 :30 :40 .50 FIGURE 31. Results of stimulating the left splanchnic nerves, 4:25-:28, after removal of the left adrenal gland; and of stimu- lating the right splanchnic nerves, 4:49-:51 and 5:23-:25, with right adrenal gland present. Elliott's evidence that in the cat the splanchnic innervation of the adrenals is not crossed has al- ready been mentioned. If the gland is removed on one side, therefore, stimulation of the nerves on that side causes no discharge from the opposite gland. As the above experiments clearly show, splanchnic stimulation on the glandless side results in no shortening of the coagulation time ; whereas, in the same animals, stimulation of the nerves on 170 BODILY CHANGES the other side (still connected with the adrenal gland) produces a sharp hastening of the clotting process. The splanchnics innervate the intestines and liver even though the adrenal gland is removed. The foregoing experiments indicate that the nerve impulses delivered to these organs do not influence them in any direct manner to accelerate the speed of coagulation. Indeed, in one of the experiments (Dec. 4, see Fig. 31) a high reading about ten min- utes after splanchnic stimulation on the glandless side suggests the possibility of an opposite effect. Direct stimulation of the hepatic nerves on one occasion was followed by a change of the clotting time from 4.5, 5, 4.5, 4.5 minutes during twenty-five minutes before stimulation to 4.5, 7, and 6 minutes during twenty minutes after stimulation. Since with the adrenals present stimulation of hepatic nerves induces alteration of glycogen in the liver and quick increase of blood sugar, 2 just as splanchnic stimulation does, the failure of the blood to clot faster after stimulation of the hepatic nerves confirms the evidence already offered that faster clotting when adrenin is increased in the blood is not due to a larger amount of sugar pres- ent (see p. 159). The liver and intestines cannot be made to shorten clotting time by stimulation of their nerves, but, as has already been shown (see p. 157), FASTEE COAGULATION IN EMOTION 171 neither can adrenin act by itself to hasten the clot- ting process. Apparently the effect is produced by cooperation between the adrenals and the liver (and possibly also the intestines) . Somewhat simi- lar cooperation is noted in the organization of sugar metabolism; splanchnic stimulation in the absence of the adrenal glands does not increase blood sugar, 3 and in the absence of the liver adre- nin is without influence. 4 The variations of effect noted after splanchnic stimulation can be accounted for by variations in the adrenin content of the glands. Elliott 5 found, as previously stated, that animals newly brought into strange surroundings may have a con- siderably reduced amount of adrenin in their adre- nals. The animals used in our experiments had been for varying lengths of time in an animal house in which barking dogs were also kept, and were therefore subject to influences which would be likely to discharge the glands. The evidence that stimulation of splanchnic nerves, with accompanying increase of adrenal secretion, results in more rapid clotting of blood is especially interesting in relation to the experiments previously described, which showed that in pain and emotional excitement there is an increased secretion of adrenin into the blood. Does the adre- nin thus liberated have any effect on the rate of coagulation ! The observations here recorded were 172 BODILY CHANGES made in order to obtain an answer to that ques- tion. COAGULATION HASTENED BY 'TAINFUL" STIMULATION In the experiments on the action of stimuli which in the unanesthetized animal would cause pain, it will be recalled that f aradic stimulation of a large nerve trunk (the stump of the cut sciatic) I I I i i i i i i i 4:00 :10 :20 :30 :40 ;50 6:00 30 :30 :40 FIGURE 32. Three shortenings of coagulation time after stimu- lation of the left sciatic nerve, at 4:23-:25, at 4:45-:50 (stronger), andat5:15-:17. and operation under light anesthesia were the methods used to affect the afferent nerves. El- liott 6 found that repeated excitation of the sci- atic nerve was especially efficient in exhausting the adrenal glands of their adrenin content, and also FASTER COAGULATION IN EMOTION 173 that this reflex persisted after removal of the cere- bral hemispheres. It was to be expected, there- fore, that with well-stored glands, sciatic stimula- tion, even in the decerebrate animal, would call forth an amount of adrenal secretion which would decidedly hasten clotting. The following case il- lustrates such a result : Dec. 12. A cat was anesthetized with ether at 3.45 and the left sciatic nerve was bared. Decere- bration was completed at 3.57. The clotting time of the blood began to be tested six minutes later: 4.03 4 minutes 4.53 2.5 minutes .083.5 " .577 " .133.5 " 5.067.5 .18-4.5 " .15 to .17 Stimulation of .23 to .25 Stimulation of left sciatic, left sciatic. 5.17 4 minutes 4. 26 2.5 minutes .22 4.5 " .293.5 " .275.5 " .344 .365.5 " .405 " .467 " .45 to .50 Stimulation of left sciatic. The results obtained in this case, which were similar to results in other cases, are represented graphically in Fig. 32. The coagulation time was becoming gradually more prolonged, but each excitation of the sciatic nerve was followed by a marked shortening. The strength of stimu- lation was not determined with exactness, but it 174 BODILY CHANGES is worthy of note that the current used in the first and the third stimulations was weaker than could be felt on the tongue, whereas that used in the second was considerably stronger, though it did not produce reflex spasms. Mere tying of the nerve is capable of producing a marked shortening of coagulation, as the follow- ing figures show : Oct. 21. 10.57 cat under ether, and urethane given : 11.11 8.5 minutes .238.5 " .32 to .35 Left sciatic bared and tied. .37 1.5 minutes .415.5 " .507 " 12.028.5 Stimulation of the crural nerve had similar effects, reducing the clotting time in one instance from a succession of 3, 3, and 3.5 minutes to 1.5 minutes shortly after the application of the cur- rent, with a return to 3.5 minutes at the next test. Operative procedures performed under light anaesthesia (i. e., with the more persistent reflexes still present), or reduction of anesthesia soon after operation, resulted in a remarkable shortening of the coagulation time : Nov. 8. A cat was etherized and tracheoto- mized. The abdomen was then opened and a liga- ture was drawn around the hepatic nerves. The FASTER COAGULATION IN EMOTION 173 operation was completed at 2.25. At 2.50 the etherization became light and the rate of clotting began to be faster: 2.50 6 minutes 3.153.5 minutes 3.005.5 " .204.5 " .103.5 .307.5 " Nov. 11. A female cat, very quiet, was placed in the holder at 1.55. The animal was not excited. At 2.10 etherization was begun; the animal was then tracheotomized, and the femoral artery was exposed. 2.21 4.5 minutes '.26 4.5 " Anesthesia lessened. .323.5 " " light. .35 Abdomen opened. .47 1.5 minutes. .521 " .55 Ligature passed around hepatic nerves. .57 1.5 minutes. Anesthesia light; corneal reflex present. 3.023 " .07 3 " Some hepatic nerves cut. .12 4.5 " Rest of hepatic nerves cut. .225 " The results of this experiment are shown graph- ically in Fig. 33. Nov. 13. A cat was etherized at 1.55, tracheoto- mized, and the femoral artery laid bare. As soon as these preparations were completed, the ether was removed and anesthesia became light. The blood clotted thus : 176 BODILY CHANGES 2.08 6 minutes .154 .202 Anesthesia light. Etherization begun again. .272.5 .303.5 .355.5 .505.5 In the foregoing and in other similar instances, a condition of surgical injury, whether just made i i i i i 830 30 :40 *0 8:00 :10 *0 FIGURE 33. Shortening of coagulation time during an operation under light anes- thesia. At 2 :35 the abdomen was opened, at 2:55 a ligature was passed around the hepatic nerves. or being made, was accompanied by more rapid clotting of blood when the degree of anesthesia was lessened. This condition was one which, if allowed to go further in the same direction, would result in pain. Both direct electrical stimulation and also surgical operation of a nature to give pain in the unanesthetized animal result, therefore, in faster clotting. FASTER COAGULATION IN EMOTION 177 It is worthy of note that after decerebration clot- ting apparently occurred no faster because the ab- domen had been opened, although in the deeere- brate state etherization was suspended. The mechanism for reflex control of the adrenals may not be higher than the corpora quadrigemina, as Elliott has shown, but the discharge from the glands seems to be more certain to occur when the cerebrum is present and is permitted even slightly to operate. COAGULATION HASTENED IN EMOTIONAL EXCITEMENT The evidence for emotional secretion of the adre- nal glands has already been presented. As was noted in my earlier observations on the motions of the alimentary canal (see p. 14), cats differ widely in their emotional reaction to being bound; some, especially young males, become furious; others, especially elderly females, take the experience quite calmly. This difference of attitude was used with positive results, the reader will recall, in the experiments on emotional glycosuria ; there seemed a possibility likewise of using it to test the effect of emotions on blood clotting. To plan formal ex- periments for that purpose was not necessary, be- cause in the ordinary course of the researches here reported, the difference in effects on the blood be- tween the violent rage of vigorous young males and the quiet complacency of old females was early 178 BODILY CHANGES noted. Indeed, the rapid clotting which accom- panied excitement not infrequently made necessary an annoying wait till slower clotting would permit the use of experimental methods for shortening the process. The animals used on November 11 and 13 (see pp. 175, 176) are examples of calm acceptance of being placed on the holder ; and furthermore, these animals were anesthetized without much dis- turbance. As the figures indicate, the clotting from the first occurred at about the average rate. In sharp contrast to these figures are those ob- tained when a vigorous animal is angered : Oct. 30. A very vigorous cat was placed on the holder at 9.08. It at once became stormy, snarling, hissing, biting, and lashing its big tail. At 9.12 etherizing was begun and that intensified the ex- citement. By 9.15 the femoral artery was tied. The clotting time of the blood for an hour after the ether was first given was as follows : 9.18 0.5 minute 9.43 1 minute .19-! " .450.5 " .221 " .490.5 " .241 " .520.5 " .261 " .540.5 " .281.5 " .571 311 " 10.000.5 " .330.5 " .020.5 " .350.5 " .061 .380.5 " .090.5 " .390.5 " .110.5 " .411 " .131 FASTEK COAGULATION IN EMOTION 179 Twenty-four observations made during the hour showed that the clotting time in this enraged ani- mal averaged three-fourths of a minute and was never longer than a minute and a half. The clots were invariably a solid jelly. The persistence of the rapid clotting for so long a period after anes- thesia was started may have been in part due to continued, rather light, etherization, for Elliott 7 found that etherization itself could reduce the adrenin content of the adrenal glands. The shortened clotting did not always persist so long as in the foregoing instance. The brief period of faster clotting illustrated in the following case was typical of many : Nov. 18. A cat that had been in stock for some time was placed on the holder at 2.13, and was at once enraged. Two minutes later etherization was started. The hairs on the tail were erect. The clotting was as follows : 2.25 1 minute. 2.31 4.5 minutes .270.5 " .373.5 " .282 " .474.5 " It seems probable that in this case just as in some of the cases in which the splanchnic nerves were stimulated (see p. 166), the adrenals had been well-nigh exhausted because of the cat's being caged near dogs, and that the emotional flare-up practically discharged the glands, for repeated at- 180 BODILY CHANGES tempts later to reproduce the initial rapid clotting by stimulation of the splanchnic nerves were with- out result. Evidence presented in previous chapters makes wholly probable the correctness of the inference that the faster coagulation which follows emotional excitement is due to adrenal discharge from splanchnic stimulation. In this relation the effect of severance of the splanchnics on emotional accel- eration of the clotting process is of interest. The following cases are illustrative : Oct. 29. A cat was left on the holder for ten minutes while the femoral artery was uncovered under local anesthesia. The blood removed was clotted in a half-minute. The animal was much excited. It was now quickly etherized and the brain pithed forward from the neck. The tests resulted as follows : 10.511 minute. .530.5 " .550.5 .570.5 " 11.07 Cut left splanchnic. .12 " right splanchnic. .21 3.5 minutes. .263.5 " The original record of this case is given in Fig. 34. Nov. 5. A cat was etherized at 2.35. At 2.39 artificial respiration by tracheal cannula was be- FASTER COAGULATION IN EMOTION 181 gun, the air passing through an ether bottle. The clotting occurred thus : 2,531.5 minutes ,57-1.5 " 3.05-1.5 " .15-1.5 " .25 Both splanchnics cut and tied in thorax. .35 4.5 minutes .55-4.5 " Nov. 7. A cat was etherized at 1.55 under ex citement and with tail hairs erect. At 2.13 the ani- 10:51 10:53 10:55 10:57 11:21 11:26 FIGURE 34. About two-thirds original size. Record of rapid clotting (less than a half-minute) after emotional excitement. At 11:07 thr left, at 11 12 the right splanchnic norvrs uore cut; the clotting then irqinird 3:5 minutes. The nuiU In low the time record indicate the moments when the samples uere drawn. mal was showing reflexes. The figures show the course of the experiment: 2.151.5 minutes 3.112.5 minutes .211 " .26 Cut loft splanchnic in .261 " thorax. ,311 " .35 Cut right splanchnic in ,361 u thorax. .411 tt .405 minutes .46-2 * .45-5 " ,51-2 " ,51-5.5 3.06-2 " 182 BODILY CHANGES In this instance the subsequent stimulation of the splanchnic nerves resulted again in faster clot- ting a reduction from 5.5 minutes to 3.5 minutes (see experiment Nov. 7, p. 164). The results from this experiment are expressed graphically in Fig. 35. J L 2:10 :20 -30 :40 i50 5:00 :10 :20 :80 :40 :50 FIGURE 35. Rapid clotting after emotional excitement, with slowing of the process when the splanchnic nerves were cut in the thorax (the left at 3:26, the right at 3:35). The data presented in this chapter show that such stimulation as in the unanesthetized animal would cause pain, and also such emotions as fear and rage, are capable of greatly shortening the coagulation time of blood. These results are quite in harmony with the evidence previously offered that injected adrenin and secretion from the adre- nal glands induced by splanchnic stimulation hasten clotting, for painful stimulation and emo- FASTER COAGULATION IN EMOTION 183 tional excitement also evoke activity of the adre- nals. Here, then, is another fundamental change in the body, a change tending to the conservation of its most important fluid, wrought through the adrenal glands in times of great perturbation. This bodily change and the others which occur under the same circumstances are next to be ex- amined with reference to their significance. REFERENCES 1 Cannon and Mendenhall : American Journal of Physi- ology, 1914, xxxiv, p. 251. 2 Macleod : Diabetes : its Pathological Physiology, Lon- don, 1913, pp. 68-72. 8 Gautrelet and Thomas: Comptes Rendus, Societe de Biologie, 1909, Ixvii, p. 233. 4 Bang: Der Blutzucker, Wieshaden, 1913, p. 87. 5 Elliott: Journal of Physiology, 1912, xliv, p. 379. 6 Elliott : Loc. cit., pp. 406, 407. 7 Elliott: Loc. cit., p. 388. CHAPTER XI THE UTILITY OF THE BODILY CHANGES IN PAIN AND GREAT EMOTION We now turn from a consideration of the data secured in our experiments to an interpretation of the data. One of the most important lessons of ex- perience is learning to distinguish between the facts of observation and the inferences drawn from those facts. The facts may remain unquestioned ; the explanation, however, may be changed by addi- tional facts or through the influence of more ex- tensive views. Having given this warning, I pro- pose to discuss the bearings of the results reported in the earlier chapters. Our inquiry thus far has revealed that the adrenin secreted by the adrenal glands in times of stress has all the effects in the body that are pro- duced by injected adrenin. It plays an essential role in calling forth stored carbohydrate from the liver, thus flooding the blood with sugar; it helps in distributing the blood to the heart, lungs, central nervous system and limbs, while taking it away 184 UTILITY OF BODILY CHANGES 185 from the inhibited organs of the abdomen; it quickly abolishes the effects of muscular fatigue ; and it renders the blood more rapidly coagulable. These remarkable facts are, furthermore, asso- ciated with some of the most primitive experiences in the life of higher organisms, experiences com- mon to all, both man and beast the elemental experiences of pain and fear and rage that come suddenly in critical emergencies. What is the sig- nificance of these profound bodily alterations? What are the emergency functions of secreted adrenin? THE REFLEX NATURE OF BODILY RESPONSES IN PAIN AND THE MAJOR EMOTIONS, AND THE USEFUL CHARACTER OF REFLEXES The most significant feature of these bodily re- actions in pain and in the presence of emotion- provoking objects is that they are of the nature of reflexes they are not willed movements, indeed they are often distressingly beyond the control of the will. The pattern of the reaction, in these as in other reflexes, is deeply inwrought in the workings of the nervous system, and when the appropriate occasion arises, typical organic re- sponses are evoked through inherent automatisms. It has long been recognized that the most char- acteristic feature of reflexes is their "purposive" nature, or their utility either in preserving the 186 BODILY CHANGES welfare of the organism or in safeguarding it against injury. The reflexes of sucking, swal- lowing, vomiting and coughing, for instance, need only to be mentioned to indicate the variety of ways in which reflexes favor the continuance of existence. When, therefore, these automatic re- sponses accompanying pain and fear and rage the increased discharge of adrenin and sugar are under consideration, it is reasonable to inquire first as to their utility. Numerous ingenious suggestions have been of- fered to account for the more obvious changes accompanying emotional states as, for example, the terrifying aspect produced by the bristling of the hair and the uncovering of the teeth in an access of rage. 1 The most widely applicable ex- planation proposed for these spontaneous reac- tions is that during the long course of racial experience they have been developed for quick service in the struggle for existence. Earlier writers on organic evolution pointed out the antici- patory character of these responses. According to Spencer, 2 "Fear, when strong, expresses itself in cries, in efforts to hide or escape, in palpitations and tremblings ; and these are just the manifesta- tions that would accompany an actual experience of the evil feared. The destructive passions are shown in a general tension of the muscular system, in gnashing of the teeth and protrusion of the UTILITY OF BODILY CHANGES 187 claws, in dilated eyes and nostrils, in growls ; and these are weaker forms of the actions that accom- pany the killing of prey." McDougall 3 has de- veloped this idea systematically and has suggested that an association has become established between peculiar emotions and peculiar instinctive reac- tions; thus the emotion of fear is associated with the instinct for flight, and the emotion of anger or rage with the instinct for fighting or attack. Crile 4 likewise in giving recent expression to the same view has emphasized the importance of adaptation and natural selection, operative through myriads of years of racial experience, in enabling us to account for the already channeled responses which we find established in our nervous organization. And on a principle of "phylogenetic association" he assumes that fear, born of innu- merable injuries in the course of evolution, has de- veloped into portentous foreshadowing of possible injury and has become, therefore, capable of arous- ing in the body all the offensive and defensive activities that favor the survival of the organism. Because the increase of adrenin and the increase of sugar in the blood, following painful or strong emotional experiences, are reflex in character, and because reflexes as a rule are useful responses, we are justified in the assumption that under these circumstances these reactions are useful. What, then, is their possible value! 188 BODILY CHANGES In order that these reactions may be useful they must be prompt. Such is the case. Some observations made by one of my students, Mr. H. Osgood, show that the latent period of adrenal secretion, when the splanchnic nerve is stimulated below the diaphragm, is not longer than 16 sec- onds ; and Macleod 5 states that within a few min- utes after splanchnic stimulation the sugar in the blood rises between 10 and 30 per cent. The two secretions are, therefore, almost instantly ready for service. Conceivably the two secretions might act in con- junction, or each might have its own function alone. Thus adrenin might serve in cooperation with nervous excitement to produce increase of blood sugar, or it might have that function and other functions quite apart from that. Before these possibilities are considered, however, the value of the increased blood sugar itself will be discussed. THE UTILITY OF THE INCREASED BLOOD SUGAR AS A SOURCE OF MUSCULAR ENERGY When we were working on emotional glycosuria a clue to the significance of the increase of sugar in the blood was found in McDougall's suggestion of a relation between "flight instinct" and "fear emotion," and "pugnacity instinct" and "anger emotion." And the point was made that, since the fear emotion and the anger emotion are, in UTILITY OF BODILY CHANGES 189 wild life, likely to be followed by activities (run- ning or fighting) which require contraction of great muscular masses in supreme and prolonged strug- gle, a mobilization of sugar in the blood might be of signal service to the laboring muscles. Pain and fighting is almost certain to involve pain would, if possible, call forth even greater muscular effort. "In the agony of pain almost every muscle of the body is brought into strong action/' Dar- win c wrote, for "great pain urges all animals, and has urged them during endless generations, to make the most violent and diversified efforts to escape from the cause of suffering."* * It is recognized that both pain and the major emotions may have at times depressive rather than stimulating" effects. For example, Martin and Lacey have shown (American Jour- nal of Physiology, 1014, xxxiii, p. 212) that such stimuli as would induce pain may cause a fall of blood pressure, and they suggest that the rise of blood pressure commonly report- ed at times of painful experience is due to the psychic dis- turbance that is simultaneously aroused. Conceivably there is a relation between recognizing the possibility of escape (with the psychic consequences of that possibility) and the degree of stimulating effect. Thus pains originating from the interior of the body, or from injuries sure to be made more painful by action, would not likely lead to action. On the other hand, the whip and spur illustrate the well-known excitant effect of painful stimuli. Similarly in the case of the strong emotions, the effect may be paralyzing until there is a definite deed to perform. Thus terror may be the most depressing of all emotions, but, as Dar- win pointed out (Loc. cit. f p. 81), 4< a man or animal driven through terror to desperation is endowed with wonderful strength, and is notoriously dangerous in the highest degree." 190 BODILY CHANGES That muscular work is performed by energy supplied in carbonaceous material is shown by the great increase of carbon-dioxide output in severe muscular work, which may exceed twenty times the output during rest. Furthermore, the storage of glycogen in muscle, and the disappearance of this glycogen deposit from excised muscle stimu- lated to activity, 7 or its reduction after excessive contractions produced by strychnine, 8 and the lessened ability of muscles to work if their glyco- gen store has been reduced, 9 and the simple chemical relation between sugar and the lactic acid which appears when muscles are repeatedly made to contract, are all indications that carbohydrate (sugar and glycogen) is the elective source of en- ergy for contraction. This conclusion is sup- ported in recent careful studies by Benedict and Cathcart, 10 who have shown that a small but distinct increase in the ratio between the carbon- dioxide breathed out and the oxygen breathed in during a given period (the respiratory quotient) occurs during muscular work, and that a decrease in the quotient follows, thus pointing to a larger proportion of carbohydrate burned during mus- cular work than before or after i. e., a call on the carbohydrate deposits of the body. Whether circulating sugar can be immediately utilized by active muscles has been a subject of dis- pute. The claim of Chauveau and Kaufmanu 11 UTILITY OF BODILY CHANGES 191 that a muscle uses about three and a half times as much blood sugar when active as when rest- ing, although supported by Quinquaud, 12 and by Morat and Dufourt, 13 has been denied by Pavy, 14 who failed to find any difference be- tween the sugar content of arterial and venous blood when the muscle was contracting ; and also by Magnus-Levy, 15 who has estimated that the amount of change in sugar content of the blood passing through a muscle must be so slight as to be within the limits of the error of analysis. On the other hand, when blood or Kinger's solution is repeatedly perfused through contracting heart muscle, the evidence is clear that the contained sugar may more or less completely disappear. Thus Locke and Rosenheim 16 found that from 5 to 10 centigrams of dextrose disappeared from Ringer's solution repeatedly circulated through the rabbit heart for eight or nine hours. And recently Patterson and Starling 17 have shown that if blood is perfused repeatedly through a heart-lung preparation for three or four hours, and the heart is continually stimulated by adrenin added to the blood, the sugar in the blood wholly vanishes ; or if the supply of sugar is maintained, the consumption may rise as high as 8 milligrams per gram of heart muscle per hour about four times the usual consumption. When an animal is eviscerated it may be regarded as a preparation 192 BODILY CHANGES in which the muscles are perfused with their proper blood, pumped by the heart and oxygenated by the lungs. Under these circumstances, the per- centage of sugar in the blood steadily falls, 18 because the utilization by the tissues is not com- pensated for by further supply from the liver. Thus, although there may be doubt that analyses of sugar in the blood flowing into and out from an active muscle during a brief period can be accu- rate enough to prove a clear difference, the evi- dence from the experiments above cited shows that when the supply of sugar is limited it disappears to a greater or less degree if passed repeatedly through muscular organs. The argument may be advanced, of course, that the sugar which thus disappears is not directly utilized, but must first be changed to glycogen. There is little basis for this assumption. There is, on the other hand, considerable evidence that increasing the blood sugar does, in fact, directly increase muscular efficiency. Thus Locke 19 proved that if oxygenated salt solution is perfused through the isolated rabbit heart, the beats begin to weaken after one or two hours ; but if now 0.1 per cent dextrose is added to the perfusing liquid, the beats at once become markedly stronger and may continue with very slow lessening of strength as long as seven hours. And Schumberg 20 noted that when he performed a large amount of gen- UTILITY OF BODILY CHANGES 193 eral bodily work (thus using up blood sugar) and then tested flexion of the middle finger in an ergograph, the ability of the muscle was greater if he drank a sugar solution than if he drank an equally sweet solution of "dulcin." He did not know during the experiment which solution he was drinking. These observations have been confirmed by Prantner and Stowasser, and by Frentzel. 21 In experiments on cats, Lee and Harrold 22 found that when sugar is removed from the animal by means of phlorhizin the tibialis anticus is quick- ly fatigued ; but if, after the phlorhizin treatment, the animal is given an abundance of sugar and then submitted to the test, the muscle shows a much larger capacity for work. All this evidence is, of course, favorable to the view that circulating sugar may be quickly utilized by contracting muscles. From the experimental results presented above it is clear that muscles work preferably by utilizing the energy stored in sugar, that great muscular labor is capable of considerably reducing the quan- tity of stored glycogen and of circulating sugar, and that under circumstances of a lessened sugar content the increase of blood sugar considerably augments the ability of muscles to continue con- tracting. The conclusion seems justified, there- fore, that the increased blood sugar attendant on the major emotions and pain would be of direct 194 BODILY CHANGES benefit to the organism in the strenuous muscular efforts involved in flight or conflict or struggle to be free. THE UTILITY OF INCREASED ADRENIN IN THE BLOOD AS AN ANTIDOTE TO THE EFFECTS OF FATIGUE The function which the discharged adrenin itself might have in favoring vigorous muscular con- traction has already been suggested in the chapter on the effect of adrenin in restoring the irritability of fatigued muscle. Some of the earliest evidence proved that removal of the adrenal glands has a debilitating effect on muscular power, and that injection of adrenal extract has an invigorating effect. For these reasons it seemed possible that increased adrenal secretion, as a reflex result of pain or the major emotions, might act in itself as a dynamogenic factor in the performance of mus- cular work. It was on the basis of that possibility that Nice and I tested the effect of stimulating the splanchnic nerves (thus causing adrenal secre- tion), or injecting adrenin, on the contraction of the fatigued tibialis anticus. We found, as already described, that when arterial pressure was of nor- mal height, and was prevented from rising in the legs while the splanchnic was being stimulated, there was a distinct rise in the height of contrac- tion of the fatigued muscle. And we drew the inference that adrenin set free in the blood may UTILITY OF BODILY CHANGES 195 operate favorably to the organism by preparing fatigued muscles for better response to the nervous discharges sent forth in great excitement. This inference led to the experiments by Gruber, who examined the effects of minute amounts of adrenin (0.1 or 0.5 cubic centimeter, 1:100,000), and also of splanchnic stimulation, on the thresh- old stimulus of fatigued neuro-muscular and mus- cular apparatus. Fatigue, the reader will recall, raises the threshold not uncommonly 100 or 200 per cent, and in some instances as much as 600 per cent. Best will restore the normal threshold in periods varying from fifteen minutes to two hours, according to the length of previous stimulation. If a small dose of adrenin is given, however, the normal threshold may be restored in three to five minutes. From the foregoing evidence the conclusion is warranted that adrenin, when freely liberated in the blood, not only aids in bringing out sugar from the liver's store of glycogen, but also has a remark- able influence in quickly restoring to fatigued mus- cles, which have lost their original irritability, the same readiness for response which they had when fresh. Thus the adrenin set free in pain and in fear and rage would put the muscles of the body unqualifiedly at the disposal of the nervous sys- tem; the difficulty which nerve impulses might have in calling the muscles into full activity would 196 BODILY CHANGES be practically abolished ; and this provision, along with the abundance of energy-supplying sugar newly flushed into the circulation, would give to the animal in which these mechanisms are most efficient the best possible conditions for putting forth supreme muscular efforts.* THE QUESTION WHETHER ADRENIN NORMALLY SECRETED INHIBITS THE USE OF SUGAR IN THE BODY The only evidence opposed to the conclusion which has just been drawn is that which may be found injresults which were noted by Wilenko. He injected adrenin into urethanized rabbits, usually one milligram per kilo body weight, and then found that the animals did not oxidize any part of an intravenous injection of glucose. Babbits supplied with glucose in a similar manner, but not given adrenin, have an increased respiratory quotient. Wilenko 23 concluded, therefore, that adrenin les- sens the capacity of the organism to burn carbo- hydrates. In a later paper he reported that adren- in, when added, with glucose, to physiological salt solution (Locke's), and perfused through the iso- lated rabbit heart, notably increases the use of sugar by the heart (from 2.2-2.8 to 2.9-4.3 milli- * If these results of emotion and pain are not "worked off" by action, it is conceivable that the excessive adrenin and sugar in the blood may have pathological effects. (Of. Can- non : Journal of the American Medical Association, 1911, Ivi, p. 742.) UTILITY OF BODILY CHANGES 197 grains of glucose per gram of heart muscle per hour), but that the heart removed after the animal has received a subcutaneous injection of adrenin uses much less sugar, only 0.5-1.2 milligrams per gram per hour. From these results Wilen- ko 24 concludes that the glycosuria following in- jection of adrenin is the result of disturbance of the use of sugar an effect which is not direct on the sugar-consuming organ, but indirect through action on some other organ. Wilenko's conclusion fails to account readily for the disappearance of glycogen from the liver in adrenin glycosuria. Furthermore, Lusk 25 has recently reported that the subcutaneous adminis- tration of adrenin (one milligram per kilo body weight) to dogs, simultaneously with 50 grams of glucose by mouth, interferes not at all with the use of the sugar the respiratory quotient remains for several hours at 1.0 ; i. e., at the figure which glucose alone would have given. In other words, Lusk's results with dogs are directly contradictory to Wilenko's results with rabbits. Nevertheless, Wilenko's conclusion might be quite true for the glycosuria produced by adrenin alone (which must be excessive), and yet have no bearing whatever on the glycosuria produced physiologically by splanchnic stimulation, even though some adrenin is thereby simultaneously liberated. The amount of injected adrenin used to produce 198 BODILY CHANGES adrenin glycosuria is enormous. Osgood has stud- ied in the Harvard Physiological Laboratory the effects on blood pressure of alternately stimulating the left splanchnic nerves (with the splanchnic vessels eliminated) and injecting adrenin, and by this method of comparison 26 has shown that the amount secreted after five seconds of stimula- tion varies betweet 0.0015 and 0.007 milligram. If 0.005 milligram is taken as a rather high average figure, and doubled (for two glands), the amount would be 0.01 milligram. To produce adrenin gly- cosuria, an animal weighing two kilos would be injected with two hundred times this amount. It is granted that more adrenin would be secreted if the nerves were stimulated longer than five sec- onds, and that with injection under the skin or into the abdominal cavity (to produce glycosuria), the' amount of adrenin in the blood at one time would not be so great as if the injection were into a vein; but even with these concessions the amount of ad- renin in the blood, when it has been injected to produce glycosuria, is probably very much above the amount following physiological stimulation of the glands. Other evidence that the amount of adrenin dis- charged when the glands are stimulated is not so great as the amount needed to produce glycosuria when acting alone is presented in experiments by Macleod. 27 He found that if the nerve fibres UTILITY OF BODILY CHANGES 199 to the liver were destroyed, stimulation of the splanchnic, which would cause increased adrenal secretion, did not increase the blood sugar. The increased blood sugar due to splanchnic stimula- tion, therefore, is a nervous effect, dependent, to be sure, on the presence of adrenin in the blood, but the amount of adrenin present is not in itself capable of evoking increase. Furthermore, the increased blood sugar follow- ing splanchnic stimulation may long outlast the stimulation period. The adrenals, however, as has been demonstrated by Osgood, are soon fatigued, and fail to respond to repeated stimulation. They seem to be incapable of prolonged action. Again, as Macleod 28 has shown, a rise in the sugar content of the blood can be induced, if the adrenals are intact, merely by stimulating the nerves going to the liver. The increased blood sugar of splanchnic origin, therefore, is not due to a disturbance of the use of sugar in the body, as Wilenko claims for the increase after adrenin in- jection, but is a result of a breaking down of the stored glycogen in the liver and is of nervous origin. We may conclude, therefore, that since the condi- tions of Wilenko' s observations are not compar- able with emotional conditions, his inferences are not pertinent to the present discussion ; that when both adrenin and sugar are increased in the blood 200 BODILY CHANGES as a result of excitement, the higher percentage of sugar is not due to adrenin inhibiting the use of sugar by the tissues, and that there is no evi- dence at present to show that the brief augmenta- tion of adrenal discharge, following excitement or splanchnic stimulation, affects in any deleterious manner the utilization of sugar as a source of en- ergy. Indeed, the observation of Wilenko and of Patterson and Starling, above mentioned, that ad- renin increases the use of sugar by the heart, may signify that a physiological discharge of the ad- renals can have a favorable rather than an unfa- vorable effect on the employment of sugar by the tissues. THE VASCULAR CHANGES PRODUCED BY ADRENIN FAVORABLE TO SUPREME MUSCULAR EXERTION Quite in harmony with the foregoing argument that sugar and adrenin, which are poured into the blood during emotional excitement, render the or- ganism more efficient in the physical struggle for existence, are the vascular changes wrought by increased adrenin, probably in cooperation with sympathetic innervations. The studies of volume changes of parts of the body, by Oliver and Schae- f er and others, have already been noted. Their ob- servations, it will be remembered, showed that injected adrenin drove the blood from the abdom- inal viscera into the organs called upon in emer- UTILITY OF BODILY CHANGES 201 gencies into the central nervous system, the lungs, the heart, and the active skeletal muscles. The absence of effective vasoconstrictor nerves in the brain and the lungs, and the dilation of vessels in the heart and skeletal muscles during times of increased activity, make the blood supply to these parts dependent on the height of general arterial pressure. In pain and great excitement, as we have already seen, this pressure is likely to be much elevated, and consequently the blood flow through the unconstricted or actually dilated vessels of the body will be all the more abundant. Adrenin has a well-known stimulating effect on the isolated heart causing an increase both in the rate and the amplitude of cardiac contraction. This effect accords with the general rule that adrenin simulates the action of sympathetic impulses. It is commonly stated, however, that if the heart holds its normal relations in the body, adrenin causes slowing of the beat. 29 This view is doubt- less due to the massive doses that have been employed, which are quite beyond physiological limits and which induce such enormous increases of arterial pressure that the natural influence of adrenin on heart muscle is overcome by mechanical obstacles to quick contractions and by inhibitory impulses from the central nervous system. Hos- kins and Lovellette have recently shown that when the precaution is taken to inject adrenin into a vein 202 BODILY CHANGES in a manner resembling the discharge from the adrenal glands, not only is there increased blood pressure, but generally, also, an acceleration of the pulse. 30 At the same time, therefore, that a greater amount of work, from increased arterial pressure, is demanded of the heart, blood is de- livered to the heart in greater abundance, and the muscle is excited to more rapid and vigorous pul- sations. The augmentation of the heart beat is thus coordinate with the other adaptive functions of the adrenal glands in great emergencies. THE CHANGES IN RESPIRATORY FUNCTON ALSO FAVORABLE TO GREAT EFFORT The urgent need in struggle or flight is a gen- erous supply of oxygen to oxidize the metabolites of muscular contraction, and a quick riddance of the resultant carbon-dioxide from the body. The moment vigorous exercise is begun the breathing at once changes so as to bring about a more thor- ough ventilation of the lungs. And one of the most characteristic reactions of animals in pain and emotional excitement is deep and rapid respiration. Again the reflex response is precisely what would be most serviceable to the organism in the stren- uous efforts of fighting or escape that might accom- pany or follow distress or fear or rage. It is known that by such forced respirations the carbon- dioxide content of the blood can be so much re- UTILITY OF BODILY CHANGES 203 duced that the need for any breathing whatever may be deferred for as much as a minute or even longer. 31 And Douglas and Haldane 32 have found that moderately forced breathing for three minutes previous to severe muscular exertion re- sults in greatly diminishing the subsequent res- piratory distress, as well as lessening the amount of air breathed and the amount of carbon-dioxide given off. Furthermore, the heart beats less rap- idly after the performance and returns more quickly from its increased rate to normal. The forced respirations in deeply emotional experi- ences can be interpreted, therefore, as an antici- patory reduction of the carbon-dioxide in the blood, a preparation for the augmented discharge of carbon-dioxide into the blood as soon as great muscular exertion begins.* As the air moves to and fro in the lungs with each respiration, it must pass through- the fine divisions of the air tubes or bronchioles. The bronchioles are provided with smooth muscle, which, in all probability, like smooth muscle else- where in the body, is normally held in a state of * The excessive production of heat in muscular work gives rise to sweating. The evaporation of sweat helps to keep the body temperature from rising unduly from the heat of exer- tion. Again in strong emotion and in pain the "cold sweat" that appears on the skin may be regarded as a reaction anticipatory of the strenuous muscular movements that are likely to ensue. 204 BODILY CHANGES . Ionic contraction. When this tonic contraction is much increased, as in asthma, breathing becomes difficult, and even with the body at rest unusual effort is then required to maintain the minimal necessary ventilation of the lungs. During stren- uous exertion, with each breath the air must rush through the bronchioles in greatly increased vol- ume and speed. Thus in a well person "winded" with running, for example, the bronchioles might become relatively too small for the stream of air, just as they are too small in a person ill with asthma. And then some extra energy would have to be expended to force the air back and forth with sufficient rapidity to satisfy the bodily needs. It is probable that even under the most favorable con- ditions, the labored breathing in hard exercise in- volves to some degree the work of accelerating the tidal flow of the respiratory gases. This extra labor would obviously be reduced, if the tonic con- traction of the ring-muscles in the wall of the bronchioles was reduced, so that the tubules were enlarged. It has been shown by a number of in- vestigators, who have used various methods, that adrenin injected into the blood stream has as one of its precise actions the dilating of the bronchi- oles. 33 The adrenin discharged in emotional ex- citement goes to the lungs before entering into relation with any other organ except the right heart chamber; it may, therefore, have as its first UTILITY OF BODILY CHANGES 205 effect the relaxation of the smooth muscles of the lungs. This would be another very direct means of rendering the organism more efficient when fierce struggle calls for a bounteous supply of fresh air and a speedy discharge of the carbonaceous waste: EFFECTS PRODUCED IN ASPHYXIA SIMILAR TO THOSE PRODUCED IN PAIN AND EXCITEMENT All the bodily responses occurring in pain and emotional excitement have thus far been consid- ered as anticipatory of the instinctive acts which naturally follow. And as we have seen, these re- sponses can reasonably be interpreted as prepar- atory to the great exertions which may be de- manded of the organism. This interpretation of the facts is supported by the discovery that a mechanism exists whereby the changed initiated in an anticipatory manner by emotional excite- ment are continued or perhaps augumented by the exertion itself. Great exertion, such as might attend flight or conflict, would result in an excessive production of carbon-dioxide. Then, although respiratory and circulatory changes of emotional origin may have prepared the body for struggle, the emotional pro- visions for keeping the working parts at a high level of efficiency may not continue to operate, or 206 BODILY CHANGES they may not be adequate. If there is painful gasp- ing for breath in the course of prolonged and vig- orous exertion, or for a considerable period after the work has ceased, a condition of partial asphyxia has evidently been induced. This condi- tion, as everyone knows, is distinctly unfavorable to further effort. But the asphyxia itself may act as a stimulus. 84 In our examination of the influence of various conditions on the secretion of the adrenal glands, Hoskins and I 35 tested the effects of asphyxia. By use of the intestinal segment as an indicator we compared the action of blood, taken as nearly si- multaneously as possible from the vena cava above the adrenal vessels and from the femoral vein be- fore asphyxia, with blood taken from the same sources after asphyxia had been produced. The femoral venous blood after passing the capillaries of the Idfc thus acted as a standard for the same <i> blood after receiving the contribution of the adrenal veins. Asphyxia was caused by covering the trachea! cannula until respiration became labored and slow, but capable of recovery when air was admitted. It may be regarded, therefore, as not extreme. The results of the degree of asphyxia above described are shown by graphic record in Fig. 36. Blood taken from the vena cava and from the femoral vein before asphyxia ("normal") failed to UTILITY OF BODILY CHANGES 207 cause inhibition of the contractions. Blood taken from the femoral vein after asphyxia produced al- most the same effect as blood from the same vein before; asphyxia, therefore, had wrought no change demonstrable in the general venous flow. FIGURE 36. Adrenal secretion produced by as- phyxia. At 1 normal vena-cava blood applied, at 2 removed. At 3 normal blood from femoral vein applied, at 4 removed. At 5 blood from femoral vein after asphyxia applied, at 6 re- moved. At 7 blood from the vena cava after asphyxia applied. Time, half-minutes. Blood taken from the vena cava after asphyxia had, on the contrary, an effect markedly unlike blood from the same region before (compare the record after 1 and after 7, Fig. 36) it caused the 208 BODILY CHANGES typical inhibition which indicates the presence of adrenal secretion.* That the positive result obtained in moderate asphyxia is not attributable to other agencies in the blood than adrenin is indicated by the failure of asphyxial femoral blood to cause inhibition, while vena-cava blood, taken almost simultane- ously, brought about immediate relaxation of the muscle. The conclusion was drawn, therefore, that asphyxia results in increased secretion of the adrenal glands. This conclusion has been supported by Anrep, 36 who noted contraction of a denervated limb during asphyxia, though general arterial pressure rose; and by Gasser and Meek, 37 who, while studying a dog with denervated heart, found that when the * This positive result might suggest that the comparison of both femoral and vena-cava blood under each condition was unnecessary, and that a comparison merely of vena-cava blood before and after asphyxia would be sufficient. Positive results were indeed thus secured, but they occurred even when the adrenal glands were carefully removed and extreme asphyxia (i. e., stoppage of respiration) was induced. That the blood may contain in extreme asphyxia a substance or substances capable of causing inhibition of intestinal con- tractions was thus demonstrated. In one instance, after the blood was proved free from adrenin, the aorta and vena cava were tied close below the diaphragm, and the carotids were tied about midway in the neck. Extreme asphyxia was produced (lasting five minutes). Blood now taken from the heart caused marked inhibition of the beating intestinal segment. Probably, therefore, the inhibitory action of blood taken from an animal when extremely asphyxiated cannot be due to adrenin alone. UTILITY OF BODILY CHANGES 209 animal was asphyxiated, the pulse increased 90 beats per minute. These effects were not seen after exclusion of the adrenal glands. The obser- vations on the denervated heart I have recently cosfinned. 88 Asphyxia, like pain and excitement, not only lib- erates adrenin, but, as might be inferred from that fact, also mobilizes sugar. 39 And, furthermore, Starkenstein 40 has shown that the asphyxia due to carbon-monoxide poisoning is not accompanied by increased blood sugar if the adrenal glands have been removed. In case strong emotions are followed by vigor- ous exertions, therefore, asphyxia is likely to result, and this will act in conjunction with the emotional excitement and pain, or perhaps in con- tinuation of the influences of these states, to bring forth still more adrenal discharge and still further output of sugar from the liver. And these in turn would serve the laboring muscles in the manner already described. This suggestion is in accord with Macleod's 41 that the increased freeing of glycogen from the liver produced by muscular ex- ercise is possibly associated with increased carbon- dioxide in the blood. And it also harmonizes with Zuntz's statement 42 that the asphyxia of great physical exertion may call out sugar to such a de- gree that, in spite of the increased use of it in the Active muscles, glycosuria may ensue. 210 BODILY CHANGES The evidence previously adduced that adrenin causes relaxation of the smooth muscle of the bronchioles, taken in conjunction with the evidence that adrenal secretion is liberated in asphyxia, sug- gests that relief from difficult breathing may thus be automatically provided for in the organism. The well-known phenomenon of "second wind" is characterized by an almost miraculous refreshment and renewal of vigor, after an individual has per- sisted in violent exertion in spite of being "out of breath." It seems not improbable that this phe- nomenon, for which many explanations have been offered, is really due to setting in operation the supporting mechanism which, as we have seen, plays so important a role in augmenting bodily vigor in emotional excitement. The release of sugar and adrenin, the abundance of blood flow through the muscles supplying energy and les- sening fatigue and the relaxation of the bronchi- olar walls, are all occurrences which may reason- ably be regarded as resulting from asphyxia. And when they take place they doubtless do much to abolish the distress itself by which they were occa- sioned. According to this explanation "second wind" would consist in the establishment of the same group of bodily changes, leading to more efficient physical struggle, that are observed in pain and excitement. UTILITY OF BODILY CHANGES 211 THE UTILITY OP KAPID COAGULATION IN PREVENTING Loss OP BLOOD The increase of blood sugar, the secretion of adrenin, and the altered circulation in pain and emotional excitement have been interpreted in the foregoing discussion as biological adaptations to conditions in wild life which are likely to involve pain and emotional excitement, i. e., the necessities of fighting or flight. The more rapid clotting of blood under these same circumstances may also be regarded as an adaptive process, useful to the or- ganism. The importance of conserving the blood, especially in the struggles of mortal combat, needs no argument. The effect of local injury in favor- ing the formation of a clot to seal the opened ves - sels is obviously adaptive in protecting the organ- ism against hemorrhage. The injury that causes opening of blood vessels, however, is, if extensive, likely also to produce pain. And, as already shown, conditions producing pain increase adrenal secretion and hasten coagulation. Thus injury would be made less dangerous as an occasion for serious hemorrhage by two effects which the in- jury itself produces in the body the local effect on clotting at the region of injury and the general effect on the 'speed of clotting wrought by reflex secretion of adrenin. According to the argument here presented the strong emotions, as fear and anger, are rightly 212 BODILY CHANGES interpreted as the concomitants of bodily changes which may be of utmost service in subsequent ac- tion. These bodily changes are so much like those which occur in pain and fierce struggle that, as early writers on evolution suggested, the emotions may be considered as foreshadowing the suffering and intensity of actual strife. On this general basis, therefore, the bodily alterations attending violent emotional states would, as organic prepara- tions for fighting and possible injury, naturally involve the effects which pain itself would pro- duce. And increased blood sugar, increased adrenin, an adapted circulation and rapid clotting would all be favorable to the preservation of the organism that could best produce them. REFEKENCES 1 See Darwin : Expression of Emotions in Man and Ani- mals, New York, 1905, pp. 101, 117. 2 Spencer: Principles of Psychology, London, 1855. 3 McDougall : Introduction to Social Psychology, London, 1908, pp. 49, 59. 4 Crile : Boston Medical and Surgical Journal, 1910, clxiii, p. 893. 5 Macleod : Diabetes, etc., p. 80. 6 Darwin : Loc. cit. f p. 72. 7 Nasse : Archiv f iir die gesammte Physiologic, 1869, ii, p. 106; 1877, xiv, p. 483. 8 Frentzel: Archiv fur die gesammte Physiologic, 1894, Ivi, p. 280. 9 Zuntz : Oppenheimer's Handbuch der Biochemie, Jena, 1911, iv (first half), p. 841. UTILITY OF BODILY CHANGES 213 10 Benedict and Cathcart : Muscular Work, a Metabolic Study, Washington, 1913, pp. 85-87. 11 Chauveau and Kauf mann : Comptes Rendus, Academic des Sciences, 1886, ciii, p. 1062. 12 Quinquaud : Comptes Rendus, Societe de Biologic, 1886, xxxviii, p. 410. 13 Morat and Dufourt: Archives de Physiologic, 1892, xxiv, p. 327. 14 Pavy: The Physiology of the Carbohydrates, London, 1894, p. 166. 15 Magnus-Levy : v. Noorden's Handbuch der Pathologic des Stoffwechsels, 1906, i, p. 385. 16 Locke and Rosenheim : Journal of Physiology, 1907, xxxvi, p. 211. 17 Patterson and Starling: Journal of Physiology, 1913, xlvii, p. 143. 18 See Macleod and Pearce: American Journal of Physi- ology, 1913, xxxii, p. 192. Pavy and Siau : Journal of Physi- ology, 1903, xxix, p. 375. Macleod: American Journal of Physiology, 1909, xxiii, p. 278. 10 Locke : Centralblatt f iir Physiologic, 1900, xiv, p. 671. 20 Schumbcrg : Archiv f iir Physiologic, 1896, p. 537. 21 Frentzel : Archiv f iir Physiologic, 1899, Supplement Band, p. 145. 22 Lee and Harrold : American Journal of Physiology, 1900, iv, p. ix. 23 Wilenko : Biochemische Zeitschrif t, 1912, xlii, p. 58. 24 Wilenko : Archiv f iir experimentelle Pathologic und Pharmakologie, 1913, Ixxi, p. 266. 25 Lusk : Proceedings of the Society for Experimental Biology and Medicine, 1914, xi, p. 49. Also Lusk and Riche: Archives of Internal Medicine, 1914, xiii, p. 68. 28 See Elliott : Journal of Physiology, 1912, xliv, p. 376. 27 Macleod : Diabetes, etc., pp. 64-73. 28 Macleod: Diabetes, etc., pp. 68-72. 29 See Biedl : Die Innere Sekretion, 1913, i. p. 464. 30 Hoskins and Lovellette : Journal of the American Med- ical Association, 1914, Ixiii, p. 317. 214 BODILY CHANGES 81 See Haldane and Priestley : Journal of Physiology, 1905, xxxii, p. 255. 82 Douglas and Haldane : Journal of Physiology, 1909, xxxix, p. 1. 83 See Januschke and Pollak : Archiv f iir experimentelle Pathologic und Pharmakologie, 1911, Ixvi, p. 205. Trendelen- burg : Zentralblatt f iir Physiologic, 1912, xxvi, p. 1. Jackson : Journal of Pharmacology and Experimental Therapeutics, 1912, iv, p. 59. 84 Of. Hoskins and McClure : Archives of Internal Medi- cine, 1912, x, p. 355. 85 Cannon and Hoskins : American Journal of Physiology, 1911, xxix, p. 275. Anrep: Journal of Physiology, 1912, xlv, p. 307. a 7 Gasser and Meek : American Journal of Physiology, 1914, xxxiv, p. 63. 8Cannon: American Journal of Physiology, 1919, 1, p. 399. 89 For evidence and for references to this literature, see Bang : Der Blutzucker, Wiesbaden, 1913, pp. 104-108. 40 Starkenstein : Loc. cit., p. 94. 41 Macleod: Diabetes, etc., p. 184. 42 Zuntz : Loc. cit., p. 854, CHAPTER XII THE ENERGIZING INFLUENCE OF EMOTIONAL EXCITEMENT The close relation between emotion and muscu- lar action has long been perceived. As Sher- rington * has pointed out, "Emotion 'moves' us, hence the word itself. If developed in intensity, it impels toward vigorous movement. Every vigor- ous movement of the body . . . involves also the less noticeable cooperation of the viscera, es- pecially of the circulatory and respiratory. The extra demand made upon the muscles that move the frame involves a heightened action of the nutrient organs which supply to the muscles the material for their energy." The researches here reported have revealed a number of unsuspected ways in which muscular action is made more effi- cient because of emotional disturbances of the viscera. Every one of the visceral changes that have been noted the cessation of processes in the alimentary canal (thus freeing the energy supply for other parts) ; the shifting of blood from the 215 216 BODILY CHANGES abdominal organs, whose activities are deferable, to the organs immediately essential to muscular exertion (the lungs, the heart, the central nervous system) ; the increased vigor of contraction of the heart ; the quick abolition of the effects of muscu- lar fatigue ; the mobilizing of energy-giving sugar in the circulation every one of these visceral changes is directly serviceable in making the or- ganism more effective in the violent display of energy which fear or rage or pain may involve. "KESERVOIRS OP POWER" That the major emotions have an energizing effect has been commonly recognized.* Darwin testified to having heard, "as a proof of the exciting nature of anger, that a man when ex- cessively jaded will sometimes invent imaginary offences and put himself into a passion, uncon- sciously for the sake of reinvigorating him- self; and," Darwin 2 continues, "since hearing this remark, I have occasionally recognized its full truth." Under the impulse of fear also, men have been known to achieve extraordinary feats of running and leaping. McDougall 3 cites the in- * Kussell (The Pima Indians, United States Bureau of Ethnology, 1908, p. 243) relates a tale told by the Indians to their children, in which an injured coyote was chasing some quails. "Finally the quails got tired," according to the story, "but the coyote did not, for he was angry and did not feel f atigue." ENEEGIZING INFLUENCE 217 stance of an athlete who, when pursued as a boy by a savage animal, leaped over a wall which he could not again "clear" until he attained his full stature and strength. The very unusual abilities, both physical and mental, which men have exhib- ited in times of stress were dealt with from the psychological point of view by William James 4 in one of his last essays. He suggested that in every person there are "reservoirs of power" which are not ordinarily called upon, but which are nevertheless ready to pour forth streams of energy if only the occasion presents itself. These figurative expressions of the psychologist receive definite and concrete exemplification, so far as the physical exhibitions of power are concerned, in the highly serviceable bodily changes which have been described in the foregoing chapters. It would doubtless be incorrect to attempt to account for all the increased strength and tireless endurance, which may be experienced in periods of great excitement, on the basis of abundant sup- plies provided then for muscular contraction, and a special secretion for avoiding or abolishing the depressive influences of fatigue. Tremors, mus- cular twitchings, the assumption of characteristic attitudes, all indicate that there is an immensely augmented activity of the nervous system an ac- tivity that discharges powerfully even into parts not directly concerned in struggle, as, for exam- 218 BODILY CHANGES pie, into the muscles of voice, causing peculiar cries or warning notes; into the muscles of the ears, drawing them back or causing them to stand erect, and into the small muscles about the lips, tightening them and revealing the teeth. The typical appearances of human beings, as well as lower animals, when in the grip of such deeply agitating emotions as fear and rage, are so well recognized as to constitute a primitive and com- mon means of judging the nature of the experience through which the organism is passing. This "pat- tern" response of the nervous system to an emo- tion-provoking object or situation is probably capable of bringing into action a much greater number of neurones in the central nervous system than are likely to be concerned in even a supreme act of volition. The nervous impulses delivered to the muscles, furthermore, operate upon organs well supplied with energy-yielding material and well fortified by rapidly circulating blood and by secreted adrenin, against quick loss of power be- cause of accumulating waste. Undet such circum- stances of excitement the performance of extraor- dinary feats of strength or endurance is natural enough.* * If individual neurones obey the law of either supreme ac- tion or inaction, the "all-or-none law," the only means of securing a graded response is through variation of the number of neurones engaged in action the more, the greater the re- sulting manifestation of strength. ENERGIZING INFLUENCE 219 In connection with the conception that strong emotion has a dynamogenic value, it is of interest to note that on occasions when great demands are likely to be placed on the neuro-muscular system in the doing of unusual labors, emotional excitement is not uncommonly an accompaniment. In order to emphasize points in the argument developed thus far, I propose to cite some examples of the association of emotional excitement with remark- able exhibitions of power or resistance to fatigue. THE EXCITEMENTS AND ENERGIES OP COMPETITIVE SPORTS Already in an earlier account (see p. 75) I have mentioned finding sugar in the urine in approxi- mately fifty per cent of a group of college football players after the most exacting game of the sea- son's play. As is well understood, such games are heralded far and wide, loyal supporters of each college may travel hundreds of miles to attend the contest, enthusiastic meetings of undergraduate students are held in each college to demonstrate their devotion to the team and their confidence in its prowess indeed, the arguments for victory, the songs, the cheering, are likely to be so disturb- ing to the players, that before an important con- test they are not infrequently removed from college surroundings in order to avoid being over- wrought when the contest conies. On the day of the contest the excitement is mul- 220 BODILY CHANGES tiplied manyfold. There is practically a holiday in college and to a large extent in the city as well. The streets are filled with eager supporters of each team as the hosts begin to gather at the field. As many as 70,000 spectators may be present, each one tense and strongly partisan. The student bands lead the singing, by thousands of voices, of songs which urge to the utmost effort for the college ; and, in anticipation, these songs also cele- brate the victory. Into the midst of that huge, cheering, yelling, singing, flag-waving crowd, the players are wel- comed in a special outburst of these same demon- strations of enthusiasm. Soon the game begins. The position of every player is known, if not be- cause of previous acquaintance and recognition, because card-diagrams give the information. Every important play is seen by the assembled thousands, and the player who makes it is at once announced to all, and is likely to be honored by his multitudinous college mates in a special cheer, ending in his name. Any player who, by infrac- tion of the rules or failure to do his part, loses ground gained by his team is also known. The man who is "played out" in efforts to win for his team and college, and consequently has to leave the field, is welcomed to the side lines by acclamations suited for a great hero. In short, every effort is made, through the powerful incentives of censure ENEKGIZINQ INFLUENCE 221 and a flaunting recognition, to make each member of the team realize vividly his responsibility, both personal and as one of a group, for the supreme, all-important result victory for his college. This responsibility works tremendously on the emotions of the players. In the dressing room before a critical contest I have seen a "gridiron warrior," ready in canvas suit, cleated shoes, and leather helmet, sitting grimly on a bench, his fists clenched, his jaws tight, and his face the color of clay. He performed wonderfully when the game began, and after it was over there was a large per- centage of sugar in his urine ! Probably no sport requires a more sustained and extreme display of neuro-muscular effort than American football. And from the foregoing description of the condi- tions that surround the contests it is easy to real- ize that they conspire to arouse in the players ex- citements which would bring forth very efficiently the bodily reserves for use in the fierce struggle which the game requires. What is true of football is true, though perhaps to a less degree, of the racing sports, as running and rowing. Again great multitudes attend the events, the contests are followed closely from be- ginning to end, and as the goal is approached the cheering and cries for victory gather in volume and intensity as if arranged for a thrilling climax. The whole setting is most highly favorable to the 222 BODILY CHANGES dramatic development of an acme of excitement as the moment approaches when the last desperate effort to win is put forth. FRENZY AND ENDURANCE IN CEREMONIAL AND OTHER DANCES Dancing, which formed a significant feature of primitive rituals, has always heen accompanied by exciting conditions, and not unusually was an ex- hibition of remarkable endurance. In the trans- fer of the Ark to Zion there were processions and sacrifices, and King David "danced before the Lord with all his might." Mooney 5 in his ac- count of dances among the American Indians tells of a young man who in one of the ceremonials danced three days and nights without food, drink or sleep. In such a terrible ordeal the favoring presence of others, who through group action help to stimulate both the excitement and the activities, must be an important element in prolonging the efforts of the individual. In the history of religious manias e there are many instances of large numbers of people becom- ing frenzied and then showing extraordinary en- durance while dancing. In 1374 a mania broke forth in Germany, the Netherlands and France, in which the victims claimed to dance in honor of Saint John. Men and women went about dancing hand in hand, in pairs, or in a circle, on the streets, in the churches, at their homes, or wherever they ENERGIZING INFLUENCE 223 might be, hour after hour without rest. While dancing they sang, uttered cries, and saw visions. Whole companies of .these crazy fanatics went dancing along the public roads and into the cities, until they had to be interfered with. In 1740 an extraordinary sect, known as the "Jumpers," arose in Wales. According to the description given by Wesley, their exercises were not unlike those of certain frenzied states among the Indians. "After the preaching was over," Wesley 7 wrote, "anyone who pleased gave out a verse of a hymn; and this they sung over and over again, with all their might and main, thirty or forty times, till some of them worked them- selves into a sort of drunkenness or madness ; they were then violently agitated, and leaped up and down in all manner of postures, frequently for hours together." There were sometimes thou- sands at a single meeting of the Jumpers, shouting out their excitement and ready to leap for joy. 8 Wesley has also described instances of tremendous emotional outburst at Methodist meetings which he addressed. "Some were torn with a kind of convulsive motion in every part of their bodies, and that so violently that often four or five per- sons could not hold one of them. I have seen many hysterical or epileptic fits," he wrote, "but none of them were like these in many respects." Among the dervishes likewise the dance is ac- 224 BODILY CHANGES companied by intense excitement and apparently tireless movements. "The cries of *Ya Allah !' are increased doubly, as also those of 'Ya Hoo !' with frightful howlings shrieked by the dervishes to- gether in the dance." . . . "There was no reg- ularity in their dancing, but each seemed to be per- forming the antics of a madman ; now moving his body up and down; the next moment turning round, then using odd gesticulations with his arms, next jumping, and sometimes screaming." . . . "At the moment when they would seem to stop from sheer exhaustion the sheikh makes a point of exciting them to new efforts by walking through their midst, making also himself most violent movements. He is next replaced by two elders, who double the quickness of the step and the agita- tion of the body; they even straighten themselves up from time to time, and excite the envy or emu- lation of others in their astonishing efforts to con- tinue the dance until their strength is entirely exhausted." Such is the frenzy thus developed that the performers may be subjected to severe pain, yet only show signs of elation. In all these dances the two most marked features are the intense excitement of those who engage in them and the very remarkable physical endurance which they manifest. Although there is no direct evidence, such as was obtained in examining the football players, that bodily changes favorable to ENEEGIZING INFLUENCE 225 great neuro-muscular exertion are developed in these furies of fanaticism, it is highly probable that they are so developed, and that the feats of fortitude which are performed are to a large ex- tent explicable on the basis of a "tapping of the reservoirs of power" through the emotional ex- citement. THE FIERCE EMOTIONS AND STRUGGLES OF BATTLE Throughout the discussion of the probable sig- nificance of the bodily changes in pain and great emotion, the value of these changes in the strug- gles of conflict or escape was emphasized. In hu- man beings as well as in lower animals the wildest passions are aroused when the necessities of com- bat become urgent. One needs only to glance at the history of warfare to observe that when the primitive emotions of anger and hatred are per- mitted full sway, men who have been considerate and thoughtful of their fellows and their fellows' rights suddenly may turn into infuriated savages, slaughtering innocent women and children, muti- lating the wounded, burning, ravaging, and looting, with all the wild fervor of demons. It is in such excesses of emotional turbulence that the most astonishing instances of prolonged exertion and incredible endurance are to be found. Probably the fiercest struggles between men that are recorded are those which occurred when 226 BODILY CHANGES the wager of battle was a means of determining innocence or guilt. In the corners of the plot se- lected for the combat a bier was prepared for each participant, as a symbol that the struggle was for life or death. Each was attended by his relatives and followers, and by his father confessor. 10 After each had prayed to God for help in the com- ing combat, the weapons were selected, the sacra- ment was administered, and the battle was begun. The principals fought to the end with continuous and brutal ferocity, resembling the desperate en- counters of wild beasts. A fairly illustrative ex- ample is furnished in an incident which followed the assassination of Charles the Good of Flanders in 1127. One of the accomplices, a knight named Guy, was challenged for complicity by another named Herman. Both were renowned warriors. Herman was speedily unhorsed by Guy, who with his lance frustrated all Herman's attempts to re- mount. Then Herman disabled Guy's horse, and the combat was renewed on foot with swords. Equally skilful in fence, they continued the strug- gle till fatigue compelled them to drop sword and shield, whereupon they wrestled for the mastery. Guy threw his antagonist, fell on him, and beat him in the face with his gauntlets till he seemed to be motionless ; but Herman had quietly slipped his hand below the other's coat of mail and, grasping the testicles, with a mighty effort wrenched them ENEBGIZING INFLUENCE 227 away. Immediately Guy fell over and expired. 11 In such terrific fights as these, conducted in the extremes of rage and hate, the mechanisms for reenf orcing the parts of the body which are of primary importance in the struggle are brought fully into action and are of utmost value in secur- ing victory. THE STIMULATING INFLUENCE OF WITNESSES AND OF Music It is noteworthy that in all the instances thus far cited in the great games, in dancing, and in fighting two factors are present that are well known to have an augmenting effect both in the full development of emotions and in the perform- ance of unusual muscular labors. One of these is the crowd of witnesses or participants, who con- tribute the "mob spirit" that tends to carry the actions of the individual far beyond the limits set by any personal considerations or prudencies. The other is the influence of music. As Darwin long ago indicated, music has a wonderful power of recalling in a vague and indefinite manner strong emotions which have been felt by our an- cestors in long-past ages. Especially is this true of martial music. For the grim purposes of war the reed and the lute are grotesquely ill-suited ; to rouse men to action strident brass and the jarring instruments of percussion are used in full force. The influence of martial music on some persons 228 BODILY CHANGES is so profound as to cause the muscles to tremble and tears to come to the eyes both indications of the deep stirring of emotional responses in the body. And when deeds of fortitude and fierce ex- ertion are to be performed the effectiveness of such music in rousing the aggressive emotions has long been recognized. The Romans charged their foes amid the blasts of trumpets and horns. The ancient Germans rushed to battle, their forces spurred by the sounds of drums, flutes, cymbals and clarions. There is a tradition that the Hunga- rian troops are the worst in Europe, until their bands begin to play then they are the best! The late General Linevitch is quoted as saying : "Music is one of the most vital ammunitions of the Russian army. Without music a Russian soldier would be dull, cowardly, brutal and inefficient. From music he absorbs a magic power of endurance, and for- gets the sufferings and mortality. It is a divine dynamite." And Napoleon is said to have testified that the weird and barbaric tunes of the Cossack regiments infuriated them to such rage that they wiped out the cream of his army. 12 A careful consideration of the use of martial music in war- fare would perhaps bring further interesting evi- dence that its function is to reenforce the bodily changes that attend the belligerent emotions. Only a few instances of the combination of ex- treme pain, rage, terror or excitement, and tre- ENERGIZING INFLUENCE 229 mendous muscular power have been given in the preceding pages. Doubtless in numerous other conditions these two groups of phenomena occur together. In the lives of firemen and the police, in the experiences of escaping prisoners, of ship- wrecked sailors, in the struggles between pioneers and their savage enemies, in accounts of forced marches or retreats, search would reveal many ex- amples of such bodily disturbances as have been described in earlier chapters as augmenting the effectiveness of muscular efforts, and such exhibi- tions of power or endurance as are evidently far beyond the ordinary. There is every reason for believing that, were the conditions favorable to ex- perimental testing, it would be possible to demon- strate and perhaps to measure the addition to the dynamics of bodily action that appears as the ac- companiment of violent emotional disturbance. THE FEELING OF POWER In this connection it is highly significant that in times of strong excitement there is not infrequent testimony to a sense of overwhelming power that sweeps in like a sudden tide and lifts the person to a new high level of ability. A friend of mine, whose nature is somewhat choleric, has told me that when he is seized with anger, he is also pos- sessed by an intense conviction that he could crush and utterly destroy the object of his hostility. And 230 BODILY CHANGES I have heard a football player confess that just before the final game such an access of strength seemed to come to him that he felt able, on the signal, to crouch and with a jump go crashing through any ordinary door. There is intense sat- isfaction in these moments of supreme elation, when the body is at its acme of accomplishment. And it is altogether probable that the critical dan- gers of adventure have a fascination because fear is thrilling, and extrication from a predicament, by calling forth all the bodily resources and setting them to meet the challenge of the difficulty, yields many of the joys of conquest. For these reasons vigorous men go forth to seek dangers and to run large chances of serious injury. "Danger makes us more alive. We so love to strive that we come to love the fear that gives us strength for conflict. Fear is not only something to be escaped from to a place or state of safety, but welcomed as an ar- senal of augmented strength." 13 And thus in the hazardous sports, in mountain climbing, in the hunting of big game, and in the tremendous ad- venture of war, risks and excitement and the sense of power surge up together, setting free unsus- pected energies, and bringing vividly to conscious- ness memorable fresh revelations of the possibili- ties of achievement. ENERGIZING INFLUENCE 231 KEFEKENCES 1 Sherrington : The Integrative Action of the Nervous System, New York, 1906, p. 265. 2 Darwin : The Expression of Emotions in Man and Ani- mals, New York, 1905, p. 79. 3 McDougall : Introduction to Social Psychology, London, 1908, p. 50. * 4 James : The Energies of Men, p. 227, in Memories and Studies, New York, 1911. B Mooney : The Ghost-Dance Religion, United States Bureau of Ethnology, 1892-3, p. 924. Schaff: Religious Encyclopedia, New York, 1908, iii, p. 346. 7 Southey : Life of Charles Wesley, New York, 1820, ii, p. 164. 8 Southey: Loc. cit., i, p. 240. 9 Brown : The Dervishes, London, 1868, pp. 218-222, 260. 10 Majer: Geschichte der Ordalien, Jena, 1796, pp. 258- 261. 11 Lea : Superstition and Force, Philadelphia, 1892, p. 178. 12 Narodny: Musical America, 1914, xx, No. 14. 13 Hall: American Journal of Psychology, 1914, xxv, p. 154. CHAPTER XIII THE NATURE OF HUNGEK On the same plane with pain and the dominant emotions of fear and anger, as agencies which de- termine the action of organisms, is the sensation of hunger. It is a sensation so peremptory, so dis- agreeable, so tormenting, that men have commit- ted crimes in order to assuage it. It has led to cannibalism, even among the civilized. It has re- sulted in suicide. And it has defeated armies for the aggressive spirit becomes detached from larger loyalties and turns personal and selfish as hunger pangs increase in vigor and insistence. In 1905, while observing in myself the rhythmic sounds produced by the activities of the alimentary tract, I had occasion to note that the sensation of hunger was not constant but recurrent, and that the moment of its disappearance was often associ- ated with a rather loud gurgling sound as heard through the stethoscope. This and other evidence, indicative of a source of the hunger sensations in 232 THE NATURE OF HUNGER 233 the contractions of the digestive canal, I reported in 1911. 1 That same year, with the help of one of my students, A. L. Washburn, I obtained final proof for this inference. APPETITE AND HUNGER The sensations of appetite and hunger are so complex and so intimately interrelated that any discussion of either sensation is sure to go astray unless at the start there is clear understanding of the meanings of the terms. The view has been propounded that appetite is the first degree of hunger, the mild and pleasant stage, agreeable in character; and that hunger itself is a more ad- vanced condition, disagreeable and even painful the unpleasant result of not satisfying the appe- tite. 2 On this basis appetite and hunger would differ only quantitatively. Another view, which seems more justifiable, is that the two experiences are fundamentally different. Careful observation indicates that appetite is re- lated to previous sensations of taste and smell of food. Delightful or disgusting tastes and odors, associated with this or that edible substance, de- termine the appetite. It has, therefore, important psychic elements in its composition. Thus, by tak- ing thought, we can anticipate the odor of a de- licious beefsteak or the taste of peaches and cream, and in that imagination we can find pleasure. In 234 BODILY CHANGES the realization, direct effects in the senses of taste and smell give still further delight. As already noted in the first chapter, observations on experi- mental animals and on human beings have shown that the pleasures of both anticipation and realiza- tion, by stimulating the flow of saliva and gastric juice, play a highly significant role in the initiation of digestive processes. Among prosperous people, supplied with abun- dance of food, the appetite seems sufficient to en- sure for bodily needs a proper supply of nutri- ment. We eat because dinner is announced, be- cause by eating we avoid unpleasant consequences, and because food is placed before us in delectable form and with tempting tastes and odors. Under less easy circumstances, however, the body needs are supplied through the much stronger and more insistent demands of hunger. The sensation of hunger is difficult to describe, but almost everyone from childhood has felt at times that dull ache or gnawing pain referred to the lower mid-chest region and the epigastrium, which may take imperious control of human ac- tions. As Sternberg has pointed out, hunger may be sufficiently insistent to force the taking of food which is so distasteful that it not only fails to rouse appetite, but may even produce nausea. The hungry being gulps his food with a rush. The pleasures of appetite are not for him he wants THE NATURE OF HUNGER 235 quantity rather than quality, and he wants it at once. Hunger and appetite are, therefore, widely dif- ferent in physiological basis, in localization and in psychic elements. Hunger may be satisfied while the appetite still calls. Who is still hungry when the tempting dessert is served, and yet are there any who refuse it, on the plea that they no longer need it? On the other hand, appetite may be in abeyance while hunger is goading. 3 What ravenous boy is critical of his food? Do we not all know that "hunger is the best sauce"? Although the two sensations may thus exist separately, they nevertheless have the same function of leading to the intake of food, and they usually appear to- gether. Indeed, the cooperation of hunger and ap- petite is probably the reason for their being so frequently confused. THE SENSATION OP HUNGER Hunger may be described as having a central core and certain more or less variable accessories. The peculiar dull ache of hungriness, referred to the epigastrium, is usually the organism's first strong demand for food ; and when the initial or- der is not obeyed, the sensation is likely to grow into a highly uncomfortable pang or gnawing, less definitely localized as it becomes more intense. This may be regarded as the essential feature of 236 BODILY CHANGES hunger. Besides the dull ache, however, lassitude and drowsiness may appear, or faintness, or vio- lent headache, or irritability and restlessness such that continuous effort in ordinary affairs becomes increasingly difficult. That these states differ much with individuals headache in one and faint- ness in another, for example indicates that they do not constitute the central fact of hunger, but are more or less inconstant accompaniments. The "feeling of emptiness," which has been mentioned as an important element of the experience, 4 is an inference rather than a distinct datum of con- sciousness, and can likewise be eliminated from further consideration. The dull pressing sensa- tion is left, therefore, as the constant character- istic, the central fact, to be examined in detail. Hunger can evidently be regarded from the psychological point of view, and discussed solely on the basis of introspection ; or it can be studied with reference to its antecedents and to the physi- ological conditions which accompany it a consid- eration which requires the use of both objective methods and subjective observation. This psycho- physiological treatment of the subject will be de- ferred till the last. Certain theories which have been advanced with regard to hunger, and which have been given more or less credit, must first be examined. Two main theories have been advocated. The THE NATURE OF HUNGER 237 first is supported by contentions that hunger is a general sensation, arising at no special region of the body, but having a local reference. This the- ory has been more widely credited by physiologists and psychologists than the other. The other is supported by evidence that hunger has a local source and therefore a local reference. In the course of our examination of these views we shall have opportunity to consider some pertinent new observations. THE THEORY THAT HUNGER is A GENERAL SENSATION The conception that hunger arises from a gen- eral condition of the body rests in turn on the no- tion that, as the body uses up material, the blood becomes impoverished. Schiff 5 advocated this notion, and suggested that poverty of the blood in food substance affects the tissues in such manner that they demand a new supply. The nerve cells of the brain share in this general shortage of pro- visions, and because of internal changes, give rise to the sensation. Thus is hunger explained as an experience dependent on the body as a whole. Three classes of evidence are cited in support of this view: 1. "Hunger increases as time passes" a partial statement. The development of hunger as time passes is a common observation which quite ac- cords with the assumption that the condition of the 238 BODILY CHANGES body and the state of the blood are becoming con- stantly worse, so long as the need, once estab- lished, is not satisfied. While it is true that with the lapse of time hun- ger increases as the supply of body nutriment de- creases, this concomitance is not proof that the sensation arises directly from a serious encroach- ment on the store of food materials. If this argu- ment were valid we should expect hunger to become more and more distressing until death follows from starvation. There is abundant evidence that the sensation is not thus intensified; on the con- trary, during continued fasting hunger, at least in some persons, wholly disappears after the first few days. Luciani, 6 who carefully recorded the ex- perience of the faster Succi, states that after a cer- tain time the hunger feelings vanish and do not return. And he tells of two dogs that showed no signs of hunger after the third or fourth day of fasting; thereafter they remained quite passive in the presence of food. Tigerstedt, 7 who also has studied the metabolism of starvation, declares that although the desire to eat is very great during the first day of the ordeal, the unpleasant sensations disappear early, and that at the end of the fast the subject may have to force himself to take nourish- ment. The subject, "J, A./' studied by Tigerstedt and his co-workers, 8 reported that after the fourth day of fasting, he had no disagreeable feelings. THE NATURE OF HUNGER 239 Carrington, 9 after examining many persons who, to better their health, abstained from eating for different periods, records that "habit-hunger" usually lasts only two or three days and, if plenty of water is drunk, does not last longer than three days. Viterbi, 10 a Corsican lawyer condemned to death for political causes, determined to escape execution by depriving his body of food and drink. During the eighteen days that he lived he kept careful notes. On the third day the sensation of hunger departed, and although thereafter thirst came and went, hunger never returned. Still fur- ther evidence of the same character could be cited, but enough has already been given to show that after the first few days of fasting the hunger feel- ings may wholly cease. On the theory that hunger is a manifestation of bodily need, are we to sup- pose that, in the course of starvation, the body is mysteriously not in need after the third day, and that therefore the sensation of hunger disappears ? The absurdity of such a view is obvious. 2. "Hunger may be felt though the stomach be full" a selected alternative. Instances of duo- denal fistula in man have been carefully studied, which have shown that a modified sensation of hunger may be felt when the stomach is full. A famous case described by Busch u has been re- peatedly used as evidence. His patient, who lost nutriment through a duodenal fistula, was hungry 240 BODILY CHANGES soon after eating, and felt satisfied only when the chyme was restored to the intestine through the distal fistulous opening. As food is absorbed mainly through the intestinal wall, the inference is direct that the general bodily state, and not the local conditions of the alimentary canal, must ac- count for the patient's feelings. A full consideration of the evidence from cases of duodenal fistula cannot so effectively be pre- sented now as later. That in Busch's case hunger disappeared while food was being taken is, as we shall see, quite significant. It may be that the restoration of chyme to the intestine quieted hunger, not because nutriment was thus intro- duced/into the body, but because the presence of material altered the nature of gastro-intestinal activity. The basis for this suggestion will be given in due course. 3. "Animals may eat eagerly after section of their vagus and splanchnic nerves" a fallacious argument. The third support for the view that hunger has a general origin in the body is derived from observations on experimental animals. By severance of the vagus and splanchnic nerves, the lower esophagus, the stomach and the small in- testine can be wholly separated from the central nervous system. Animals thus operated upon nevertheless eat food placed before them, and may indeed manifest some eagerness for it. 12 How THE NATURE OF EUNGEB 241 is this behavior to be accounted for when the possibility of local stimulation has been eliminated save by assuming a central origin of the impulse to eat? The fallacy of this evidence, though repeatedly overlooked, is easily shown. We have already seen that appetite as well as hunger may lead to the taking of food. Indeed, the animal with all gas- tro-intestinal nerves cut may have the same in- centive to eat that a well-fed man may have, who delights in the pleasurable taste and smell of food and knows nothing of hunger pangs. Even when the nerves of taste are cut, as they were in Longet's experiments, 13 sensations of smell are still possible, as well as agreeable associations which can be roused by sight. More than fifty years ago Ludwig 14 pointed out that, even if all the nerves were severed, psychic reasons could be given for the taking of food, and yet because animals eat after one or another set of nerves is eliminated, the conclusion has been drawn by vari- ous writers that the nerves in question are thereby proved to be not concerned in the sensation of hunger. Evidently, since hunger is not required for eating, the act of eating is no testimony what- ever that the animal is hungry, and, after the nerves have been severed, is no proof that hunger is of central origin. 242 BODILY CHANGES WEAKNESS OF THE ASSUMPTIONS UNDERLYING THE THEORY THAT HUNGER is A GENERAL SENSATION The evidence thus far examined has been shown to afford only shaky support for the theory that hunger is a general sensation. The theory, fur- thermore, is weak in its fundamental assumptions. There is no clear indication, for example, that the blood undergoes or has undergone any marked change, chemical or physical, when the first stages of hunger appear. There is no evidence of any direct chemical stimulation .of the gray matter of the cerebral cortex. Indeed, attempts to excite the gray matter artificially by chemical agents have been without, results; 15 and even electrical stim- ulation, which is effective, must, in order to produce movements, be so powerful that the move- ments have been attributed to excitation of under- lying white matter rather than cells in the gray. This insensitivity of cortical cells to direct stimu- lation is not at all favorable to the notion that they are sentinels set to warn against too great diminu- tion of bodily supplies. BODY NEED MAY EXIST WITHOUT HUNGER Still further evidence opposed to the theory that hunger results directly from the using up of or- ganic stores is found in patients suffering from fever. Metabolism in fever patients is augmented, body substance is destroyed to such a degree that THE NATUEE OF HUNGER 243 the weight of the patient may be greatly reduced, and yet the sensation of hunger under these condi- tions of increased need is wholly lacking. Again, if a person is hungry and takes food, the sensation is suppressed soon afterwards, long before any considerable amount of nutriment could be digested and absorbed, and therefore long before the blood and the general bodily condi- tion, if previously altered, could be restored to normal. Furthermore, persons exposed to privation have testified that hunger can be temporarily sup- pressed by swallowing indigestible materials. Cer- tainly scraps of leather and bits of moss, not to mention clay eaten by the Otomacs, would not ma- terially compensate for large organic losses. In rebuttal to this argument the comment has been made that central states as a rule can be readily overwhelmed by peripheral stimulation, and just as sleep, for example, can be abolished by bathing the temples, so hunger can be abolished by irritat- ing the gastric walls. 16 This comment is beside the point, for it meets the issue by merely assum- ing as true the condition under discussion. The absence of hunger during the ravages of fever, and its quick abolition after food or even indigestible stuff is swallowed, still further weakens the argu- ment, therefore, that the sensation arises directly from lack of nutriment in the body. 244 BODILY CHANGES THE THEORT THAT HUNGER is OF GENERAL ORIGIN DOES Nor EXPLAIN THE QUICK ONSET AND THE PERIODICITY OF THE SENSATION Many persons have noted that hunger has a sharp onset. A person may be tramping in the woods or working in the fields, where fixed atten- tion is not demanded, and without premonition may feel the abrupt arrival of the characteristic ache. The expression "grub-struck" is a pic- turesque description of this experience. If this sudden arrival of the sensation corresponds to the general bodily state, the change in the general bod- ily state must occur with like suddenness or have a critical point at which the sensation is instantly precipitated. There is no evidence whatever that either of these conditions occurs in the course of metabolism. Another peculiarity of hunger, which I have al- ready mentioned, is its intermittency. It may come and go several times in the course of a few hours. Furthermore, while the sensation is pre- vailing, its intensity is not uniform, but marked by ups and downs. In some instances the ups and downs change to a periodic presence and absence without change of rate. In my own experience the hunger pangs came and went on one occasion as follows : Came Went 123720 38- 30 40-45 4110 THE NATURE OF HUNGEE 245 Came Went 4145 4225 4320 4335 4440 4555 4615 4630 and so on, for ten minutes longer. Again in this relation, the intermittent and periodic character of hunger would require, on the theory under ex- amination, that the bodily supplies be intermittent- ly and periodically insufficient. During one mo- ment the absence of hunger would imply an abundance of nutriment in the organism, ten sec- onds later the presence of hunger would imply that the stores had been suddenly reduced, ten seconds later still the absence of hunger would imply a sudden renewal of plenty. Such zig-zag shifts of the general bodily state may not be im- possible, but from all that is known of the course of metabolism, such quick changes are highly im- probable. The periodicity of hunger, therefore, is further evidence against the theory that the sensa- tion has a general basis in the body. THE THEORY THAT HUNGER is OF GENERAL ORIGIN DOES NOT EXPLAIN THE LOCAL REFERENCE The last objection to this theory is that it does not account for the most common feature of hunger namely, the reference of the sensation to the region of the stomach. Schiff and others 1T who have supported the theory have met this 246 BODILY CHANGES objection by two contentions. First they have pointed out that the sensation is not always re- ferred to the stomach. Schiff interrogated igno- rant soldiers regarding the local reference; sev- eral indicated the neck or chest, twenty-three the sternum, four were uncertain of any region, and two only designated the stomach. In other words, the stomach region was most rarely mentioned. The second contention against the importance of local reference is that such evidence is falla- cious. An armless man may feel tinglings which seem to arise in fingers which have long since ceased to be a portion of his body. The fact that he experiences such tinglings and ascribes them to dissevered parts, does not prove that the sensa- tion originates in those parts. And similarly the assignment of the ache of hunger to any special region of the body does not demonstrate that the ache arises from that region. Such are the argu- ments against a local origin of hunger. Concerning these arguments we may recall, first, Schiff's admission that the soldiers he questioned were too few to give conclusive evidence. Further, the testimony of most of them that hunger seemed to originate in the chest or region of the sternum cannot be claimed as unfavorable to a peripheral source of the sensation. The description of feel- ings which develop from disturbances within the body is almost always indefinite. As Head 18 THE NATURE OF HUNGER 247 and others have shown, conditions in a viscus which give rise to sensation are likely not to be at- tributed to the viscus, but to related skin areas. Under such circumstances we do not dismiss the testimony as worthless merely because it may not point precisely to the source of the trouble. On the contrary, we use sucli testimony constantly as a basis for judging internal dis- orders. With regard to the contention that reference to the periphery is not proof of the peripheral origin of a sensation, we may answer that the force of that contention depends on the amount of acces- sory evidence which is available. Thus if we see an object come into contact with a finger, we are justified in assuming that the simultaneous sensa- tion of touch which we refer to that finger has re- sulted from the contact, and is not a purely central experience accidentally attributed to an outlying member. Similarly in the case of hunger all that we need as support for the peripheral reference of the sensation is proof that conditions occur there, simultaneously with hunger pangs, which might reasonably be regarded as giving rise to thoSe pangs. With the requirement in mind that peripheral conditions be adequate, let us examine the state of the fasting stomach to see whether, indeed, con- ditions may be present in times of hunger which 248 BODILY CHANGES would sustain the theory that hunger has a local outlying source. HUNGER NOT DUE TO EMPTINESS OF THE STOMACH Among the suggestions which have been offered to account for a peripheral origin of the sensation is that of attributing it to emptiness of the stom- ach. By use of the stomach tube Nicolai 19 found that when his subjects had their first intima- tion of hunger the stomach was quite empty. But, in other instances, after lavage of the stomach, the sensation did not appear for intervals vary- ing between one and a half and three and a half hours. During these intervals the stomach must have been empty, and yet no sensation was experi- enced. The same testimony was given long before by Beaumont, 20 who, from his observations on Alexis St. Martin, declared that hunger arises some time after the stomach is normally evacuated. Mere emptiness of the organ, therefore, does not explain the phenomenon. HUNGER NOT DUE TO HYDROCHLORIC ACID IN THE EMPTY STOMACH A second theory, apparently suggested by obser- vations on cases of hyperacidity, is that the ache or pang is due to the natural hydrochloric acid of the stomach but secreted while the organ is empty. Again the facts are hostile. Nicolai 21 reported THE NATURE OF HUNGER 249 that the gastric wash-water from his hungry sub- jects was neutral or only slightly acid. This testimony confirms Beaumont's statement, and is in complete agreement with the results of gastric examination of fasting animals reported by numerous experimenters. There is no secre- tion into the empty stomach during the first days of starvation. Furthermore, persons suffering from absence of hydrochloric acid (achylia gas- trica) declare that they have normal feelings of hunger. Hydrochloric acid cannot, therefore, be called upon to account for the sensation. HUNGER NOT DUE TO TURGESCENCE OF THE GASTRIC Mucous MEMBRANE Another theory, which was first advanced by Beaumont, 22 is that hunger arises from turges- cence of the gastric glands. The disappearance of the pangs as fasting continues has been accounted for by supposing that the gastric glands share in the general depletion of the body, and that thus the turgescenee is relieved.* This turgescence theory has commended itself to several recent writers. Thus Luciani 23 has accepted it, and by adding the idea that nerves distributed to the mucosa are * A bettor explanation perhaps is afforded by BoldirefFs discovery that at the end of two or three days the stomachs of fasting dogs begin to secrete gastric juice and continue the secretion indefinitely. (Boldireff, Archives Biologiques de St. Petersburg, 1905, xi, p. 98.) 260 BODILY CHANGES specially sensitive to deprivation of food lie ac- counts for the hunger pangs. Also Valenti 24 declared a few years ago that the turgescence theory of Beaumont is the only one with a sem- blance of truth in it. The experimental work re- ported by these two investigators, however, does not necessarily sustain the turgescence theory. Luciani severed the previously exposed vagi after cocainizing them, and Valenti merely cocainized the nerves; the fasting dogs, eager to eat a few minutes previous to this operation, now ran about as before, but when offered food, licked and smellcd it, but did not take it. This total neglect of the food lasted varying periods up to two hours. The vagus nerves seem, indeed, to convey impulses which affect the procedure of eating, but there is no clear evidence that those impulses arise from distention of the gland cells. The turgescence theory, moreover, does not explain the effect of taking indigestible material into the stomach. According to Pawlow, and to others who have ob- served human beings, the chewing and swallowing of unappetizing stuff does not cause any secretion of gastric juice (see p. 8). Yet such stuff when swallowed will cause the disappearance of hunger, and Nicolai found that the sensation could be abol- ished by simply introducing a stomach sound. It is highly improbable that the turgescence of the gastric glands can be reduced by either of these THE NATUEE OF HUNGER 251 procedures. The turgescence theory, furthermore, does not explain the quick onset of hunger, or its intermittent and periodic character. That the cells are repeatedly swollen and contracted within peri- ods a few seconds in duration is almost inconceiv- able. For these reasons, therefore, the theory that hunger results from turgescence of the gastric mucosa can reasonably be rejected. HUNGER THE RESULT OF CONTRACTIONS There remain to be considered, as a possible cause of hunger-pangs, contractions of the stomach and other patts of the alimentary canal. This sug- gestion is not new. Sixty-nine years ago Weber 25 declared his belief that "strong contraction of the muscle fibres of the wholly empty stomach, whereby its cavity disappears, makes a part of the sensation which we call hunger." Vierordt 2G drew the same inference twenty-five years later (in 1871), and since then Ewald, Knapp, and Hertz have declared their adherence to this view. These writers have not brought forward any direct evi- dence for their conclusion, though Hertz has cited BoldirefPs observations on fasting dogs as prob- ably accounting for what he terms "the gastric constituent of the sensation." THE EMPTY STOMACH AND INTESTINE CONTRACT The argument commonly used against the gas- trio contraction theory is that the stomach is not 252 BODILY CHANGES energetically active when empty. Thus Schiff 27 stated, "The movements of the empty stomach are rare and much less energetic than during diges- tion." Luciani 2S expressed his disbelief by as- serting that gastric movements are much more ac- tive during gastric digestion than at other times, and cease almost entirely when the stomach has discharged its contents. And Valenti 29 stated (1910), "We know very well that gastric move- ments are exaggerated while digestion is proceed- ing in the stomach, but when the organ is empty they are more rare and much less pronounced," and, therefore, they cannot account for hunger. Evidence opposed to these suppositions has been in existence for many years. In 1899 Bettmann 30 called attention to the contracted condition of the stomach after several days' fast. In 1902 Wolff 31 reported that after forty-eight hours without food the stomach of the cat may be so small as to look like a slightly enlarged duodenum. In a similar circumstance I have noticed the same ex- traordinary smallness of the organ, especially in the pyloric half. The anatomist His 32 also re- corded his observation of the phenomenon. In 1905 Boldireff 33 demonstrated that the whole gastro- intestinal tract has a periodic activity while not di- gesting. Each period of activity lasts from twenty to thirty minutes, and is characterized in the stom- ach by rhythmic contractions ten to twenty in num.- THE NATURE OF HUNGER 253 ber. These contractions, Boldireff reports, may be stronger than during digestion, and his published records clearly support this statement. The inter- vals of repose between periodic recurrences of the contractions lasted from one and a half to two and a half hours. Especially noteworthy is BoldirefPs observation that if fasting is continued for two or three days, the groups of contractions appear at gradually longer intervals and last for gradually shorter periods, and thereupon, as the gastric glands begin continuous secretion, all movements cease. OBSERVATIONS SUGGESTING THAT CONTRACTIONS CAUSE HUNGER The research, previously mentioned, on the rhythmic sounds produced by the digestive pro- cess, I was engaged in when Boldireff 's paper was published. That contractions of the alimentary canal on a gaseous content might explain the hun- ger pangs which I had noticed seemed probable at that time, especially in the light of Boldireff's ob- servations. Indeed, Boldireff 34 himself had con- sidered hunger in relation to the activities he described, but solely with the idea that hunger might provoke them; and since the activities dwin- dled in force and frequency as time passed, where- as, in his belief, they should have become more pro- nounced, he abandoned the notion of any relation 254 BODILY CHANGES between the phenomena. Did not Boldireff misin- terpret his own observations? When he was con- sidering whether hunger might cause the contrac- tions, did he not overlook the possibility that the contractions might cause hunger? A number of experiences have led to the conviction that Boldi- reff did, indeed, fail to perceive part of the signifi- cance of his results. For example, I have noticed the disappearance of a hunger pang as gas was heard gurgling upward through the cardia. That the gas was rising rather than being forced down- ward was proved by its regurgitation immediately after the sound was heard. In all probability the pressure that forced the gas from the stomach was the cause of the preceding sensation of hunger. Again the sensation can be momentarily abolished a few seconds after swallowing a small accumula- tion of saliva or a teaspoonful of water. If the stomach is in strong contraction in hunger, this re- sult can be accounted for, in accordance with the observations of Lieb and myself, 35 as due to the inhibition of the contraction by swallowing. Thus also could be explained the prompt vanishing of the ache soon after we begin to eat, for repeated swallowing results in continued inhibition.* Fur- thermore, Ducceschi's discovery 86 that hydro- * The absence of hunger in Busch's patient while food was being eaten (see p. 239) can also be accounted for in this manner. THE NATUKE OF HUNGER 255 chloric acid diminishes the tonus of the pyloric por- tion of the stomach may have its application here ; the acid would be secreted as food is taken and would then cause relaxation of the very region which is most strongly contracted. THE CONCOMITANCE OF CONTRACTIONS AND HUNGER IN MAN Although the evidence above outlined had led me to the conviction that hunger results from con- tractions of the alimentary canal, direct proof was still lacking. In order to learn whether such proof might be secured, Washburn determined to be- come accustomed to the presence of a rubber tube in the esophagus.* Almost every day for several weeks Washburn introduced as far as the stomach a small tube, to the lower end of which was attached a soft-rubber balloon about 8 centimeters in diam- eter. The tube was thus carried about each time for two or three hours. After this preliminary experience the introduction of the tube and its presence in the gullet and stomach were not at all disturbing. When a record was to be taken, the balloon, placed just within the stomach, was moder- ately distended with air, and was connected with a water manometer ending in a cylindrical chamber 3.5 centimeters wide. A float recorder resting on * Nicolai (loc. cit.) reported that although the introduction of a stomach tube at first abolished hunger in his subjects, with repeated use the effects became insignificant 256 BODILY CHANGES the water in the chamber permitted registering any contractions of the fundus of the stomach. On the days of observation Washburn would abstain from breakfast, or eat sparingly; and without taking any luncheon would appear in the laboratory about two o'clock. The recording apparatus was ar- ranged as above described. In order to avoid any error that might arise from artificial pressure on the balloon, a pneumograph, fastened below the ribs, was made to record the movements of the abdominal wall. Uniformity of these movements would show that no special contractions of the ab- dominal muscles were made. Between the records of gastric pressure and abdominal movement, time was marked in minutes, and an electromagnetic signal traced a line which could be altered by press- ing a key. All these recording arrangements were out of Washburn's sight; he sat with one hand at the key, ready whenever the sensation of hunger was experienced to make the current which moved the signal. Sometimes the observations were started before any hunger was noted ; at other times the sensa- tion, after running a course, gave way to a feeling of fatigue. Under either of these circumstances there were no contractions of the stomach. When Washburn stated that he was hungry, however, powerful contractions of the stomach were invari- ably being registered. As in my own earlier expe- THE NATURE OF HUNGER 257 rience, the sensations were characterized by peri- odic recurrences with free intervals, or by peri- odic accesses of an uninterrupted ache. The record of Washburn's introspection of his hunger pangs agreed closely with the record of his gastric con- FIGURE 37. One-half the original size. The top record represents intragastric pres- sure (the small oscillations due to respiration, the lame to contractions of the stomach); the MM <m<l tecoitl i> time in minutes (ten min- utr^ i ; t he t hii l record i.s W\s report of hunger p:mu>, the lo\ve>t record 1-5 respiration regis- teied by means of a pneumoj;iuph about the abdomen, tractions. Almost invariably, however, the con- traction nearly reached its maximum before the record of the sensation was started (see Fig. 37). This fact may be regarded as evidence that the contraction precedes the sensation, and not rice versa, as Boldireff considered it. The contrac- tions were about a half-minute in duration^ and 258 BODILY CHANGES the intervals between varied from thirty to ninety seconds, with an average of about one minute. The augmentations of intragastric pressure in Wash- burn ranged between eleven and thirteen in twenty minutes ; I had previously counted in myself eleven hunger pangs in the same time. The rate in each FIGURE 38. One-half the original size. The same conditions as in Fig. 37. (Fifteen minutes.) There was a long wait for hunger to disappear. After x, W. reported himself " tired but not hungry." The record from y to z was the continuance, on a second drum, of x to y. of us was, therefore, approximately the same. This rate is slightly slower than that found in dogs by Boldireff ; the difference is perhaps corre- lated with the slower rhythm of gastric peristalsis in man compared with that in the dog. 37 Before hunger was experienced by Washburn the recording apparatus revealed no signs of gas- tric activity. Sometimes a rather tedious period of waiting had to be endured before contractions THE NATURE OF HUNGER 259 occurred. And after they began they continued for a while, then ceased (see Fig. 38). The feeling of hunger, which was reported while the contrac- tions were recurring, disappeared as the waves stopped. The inability of the subject to control the contractions eliminated the possibility of their being artifacts, perhaps induced by suggestion. The close concomitance of the contractions with hunger pangs, therefore, clearly indicates that they are the real source of those pangs. Boldireff's studies proved that when the empty stomach is manifesting periodic contractions, the intestines also are active. Conceivably all parts of the alimentary canal composed of smooth mus- cle share in these movements. The lower esopha- gus in man is provided with smooth muscle. It was possible to determine whether this region in Washburn was active during hunger. To the esophageal tube a thin-rubber finger-cot (2 centimeters in length) was attached and lowered into the stomach. The little rubber bag was dis- tended with air, and the tube, pinched to keep the bag inflated, was gently withdrawn until resistance was felt. The air was now released from the bag and the tube farther withdrawn about 3 centi- meters. The bag was again distended with air at a manometric pressure of 10 centimeters of water. Inspiration now caused the writing lever, which recorded the pressure changes, to rise; and a 260 BODILY CHANGES slightly farther withdrawal of the tube changed the rise, on inspiration, to a fall. The former posi- tion of the tube, therefore, was above the gastric cavity and below the diaphragm. In this position FIGURE 39. One-half the original size. The top record represents compression of thin rubber bag; in the lower esophagus. The pressure in the bag varied between 9 and 13 centimeters of water. The cylin- der of the recorder was of smaller diameter than that used in the gastric records. The esophageal contractions compressed the bag so completely that, at the summits of the large oscillations, the respirations were not registered. When the oscillations dropped to the time line, the bag \\a^ about half inflated. The middle line registers time in minutes (ten minutes). The bot- tom record is W's report of hunger pangs. the bag, attached to a float recorder (with chamber 2.3 centimeters in diameter), registered the peri- odic oscillations shown in Fig. 39. Though indi- vidually more prolonged than those of the stomach, these contractions, it will be noted, occur at about the same rate. THE NATURE OF HUNGER 261 This study of hunger, reported by Washburn and myself in 1912, has since been taken up by Carlson of Chicago, and in observations on a man with a permanent gastric fistula, as well as on him- self and his collaborators, he has fully confirmed our evidence as to the relation between contrac- tions of the alimentary canal and the hunger sensa- tion. In a series of nearly a score of interesting papers, Carlson and his students 38 have greatly amplified our knowledge of the physiology of the "empty" stomach. Not only are there the contrac- tions observed by Washbum and myself, but at times these may fuse into a continuous cramp of the gastric muscle. The characteristic contrac- tions, furthermore, continue after the vagus nerve supply to the stomach has been destroyed, and, therefore, are not dependent on the reception of impulses by way of the cranial autonomic fibres. Recently Luckhardt and Carlson have brought for- ward evidence that the blood of a fasting animal if injected into the vein of a normal animal is capable of inducing in the latter the condition of cramp or tetanus in the gastric muscle mentioned above an effect which does not occur when the blood of a well-fed animal is injected. It seems possible that a substance exists in the blood which acts to excite the gastric hunger mechanism. But this point will require further investigation. With these demonstrations that contractions are 262 BODILY CHANGES the immediate cause of hunger, most of the diffi- culties confronting other explanations are readily obviated. Thus the sudden onset of hunger and its peculiar periodicity phenomena which no other explanation of hunger can account for are at once explained. In fever, when bodily material is being most rapidly used, hunger is absent. Its absence is understood from an observation made by F. T. Murphy and myself, 39 that infection, with sys- temic involvement, is accompanied by a total cessation of all movements of the alimentary canal. Boldireff observed that when his dogs were fa- tigued the rhythtoic contractions failed to appear. Being "too tired to eat" is thereby given a rational explanation. A pathological form of the sensation the inor- dinate hunger (bulimia) of certain neurotics is in accordance with the well-known disturbances of the tonic innervation of the alimentary canal in such individuals. Since the lower end of the esophagus, as well as the stomach, contracts periodically in hunger, the reference of the sensation to the sternum by the ignorant persons questioned by Schiff was wholly natural. The activity of the lower esopha- gus also explains why, after the stomach has been removed, or in some cases when the stomach is distended with food, hunger can still be experi- THE NATURE OF HUNGER 263 enced. Conceivably the intestines also originate vague sensations by their contractions. Indeed, the final banishment of the modified hunger sen- sation in the patient with duodenal fistula, de- scribed by Busch, may have been due to the les- sened activity of the intestines when chyme was injected into them. The observations recorded in this chapter have, as already noted, numerous points of similarity to Boldireff's observations 40 on the periodic activ- ity of the alimentary canal in fasting dogs. Each period of activity, he found, comprised not only wide-spread contractions of the digestive canal, but also the pouring out of bile, and of pancreatic and intestinal juices rich in ferments. Gastric juice was not secreted at these times; when it was se- creted and reached the intestine, the periodic activ- ity ceased. What is the significance of this exten- sive disturbance ? I have elsewhere presented evi- dence 41 that gastric peristalsis is dependent on the stretching of gastric muscle when tonically con- tracted. The evidence that the stomach is in fact strongly contracted in hunger i. e., in a state of high tonus has been presented above.* Thus * The "empty" stomach and esophagus contain gas (see Hertz: Quarterly Journal of Medicine, 1910, iii, p. 378; Mikulicz: Mittheilungen aus den Grenzgebieten der Medi- cin und Chirurgie, 1903, xii, p. 596). They would naturally manifest rhythmic contractions on shortening tonically on their content. 264 * BODILY CHANGES the very condition which causes hunger and leads to the taking of food is the condition, when the swallowed food stretches the shortened muscles, for immediate starting of gastric peristalsis. In this connection the observations of Haudek and Stigler 42 are probably significant. They found that the stomach discharges its contents more rap- idly if food is eaten in hunger than if not so eaten. Hunger, in other words, is normally the signal that the stomach is contracted for action; the unpleas- antness of hunger leads to eating; eating starts gastric digestion, and abolishes the sensation. Meanwhile the pancreatic and intestinal juices, as well as bile, have been prepared in the duodenum to receive the oncoming chyme. The periodic ac- tivity of the alimentary canal in fasting, therefore, is not solely the source of hunger pangs, but is at the same time an exhibition in the digestive organs of readiness for prompt attack on the food swal- lowed by the hungry animal. REFERENCES 1 Cannon : The Mechanical Factors of Digestion, London and New York, 1911, p. 204. 2 Bardier: Richet's Dictionnaire de Physiologic, article Faini, 1904, vi, p. 1. See, also, Howcll: Text-book of Physi- ology, fourth edition, Philadelphia and London, 1911, p. 285. 3 See Sternberg: Zentralblatt fur Physiologic, 1909, xxii, p. 653. Similar views were expressed by Bayle in a thesis presented to the Faculty of Medicine in Paris in 1816. 4 See Hertz : The Sensibility of the Alimentary Canal, London, 1911, p. 38. THE NATURE OF HUNGER 265 5 Schiff : Physiologie de la Digestion, Florence and Turin, 1867, p. 40. e Luciani : Das Hungern, Hamburg and Leipzig, 1890, p. 113. 7 Tigerstedt : Nagel's Handbuch der Physiologie, Berlin, 1909, i, p. 376. 8 Johanson, Landergren, Sonden arid Tigerstedt : Skandi- navisches Archiv fiir Physiologie, 1897, vii, p. 33. 9 Carrington : Vitality, Easting and Nutrition, New York, 1908, p. 555. 10 Viterbi, quoted by Bardier : Loc. cii. f p. 7. 11 Busch : Archiv fiir pathologische Anatomic und Physi- ologie und fiir klinische Medicin, 1858, xiv, p. 147. 12 See Schiff: Loc. cit., p. 37; also Ducceschi; Archivio di Fisiologia, 1910, viii, p. 579. 13 Loiiget: Traite de Physiologie, Paris, 1808, i, p. 23. 14 Ludwig : Lehrbuch der Physiologie des Menschen, Leip- zig and Heidelberg, 1858, ii, p. 584. 15 Maxwell : Journal of Biological Chemistry, 1906-7, ii, p. 194. 10 See Schiff: Loc. cit., p. 49. 17 See Schiff: Loc. cit., p. 31; Bardier; Loc. cit., p. 16. 18 Head: Brain, 1893, xvi, p. 1; 1901, xxiv, p. 345. 19 Nicolai : Ueber die Entstehung des Hungergefiihls, In- augural Dissertation, Berlin, 1892, p. 17. 20 Beaumont : The Physiology of Digestion, secoud edi- tion, Burlington, 1847, p. 51. 21 Nicolai : Loc. cit., p. 15. 22 Beaumont: Loc. cit., p. 55. 23 Luciani : Archivio di Fisiologia, 1906, iii, p. 54. Tiede- matm long ago suggested that gastric nerves become increas- ingly sensitive as fasting progresses. (Physiologie des Men- schen, Darmstadt, 1836, iii, p. 22.) 24 Valenti : Archives Italiennes de Biologic, 1910. liii, p. 94. 25 Weber: Wagner's Handworterbuch der Physiologie, 1846, iii 2 , p. 580. 20 Vierordt: Grundriss der Physiologie, Tubingen, 1871, p. 433. 27 Schiff : Loc. cit., p. 33. 266 BODILY CHANGES 18 Luciani: Loc. cit. f p. 542. 29 Valenti : Loc. cit., p. 95. 80 Bettmann : Philadelphia Monthly Medical Journal, 1899, i, p. 133. 81 Wolff: Dissertation, Giessen, 1902, p. 9. 82 His: Archiv fur Anatomie, 1903, p. 345. 83 Boldireff : Loc. cit., p. 1. 34 Boldireff: Loc. cit., p. 96. 85 See Cannon and Lieb : American Journal of Physiol- ogy, 1911, xxix, p. 267. 36 Ducceschi: Archivio per le Scienze Mediche, 197, xxi, p. 154. 37 See Cannon : American Journal of Physiology, 1903, viii, p. xxi ; 1905, xiv, p. 344. 38 See American Journal of Physiology, 1913, 1914. 39 Cannon and Murphy : Journal of the American Medi- cal Association, 1907, xlix, p. 840. 40 Boldireff: Loc. cit., pp. 108-111. 41 Cannon: American Journal of Physiology, 1911, xxix, p. 250. 42 Haudek and Stigler: Archiv fur die gesammte Physi- ologie, 1910, cxxxiii, p. 159. CHAPTER XIV THE INTERRELATIONS OF EMOTIONS Emotions gain expression through, discharges along the neurones of the autonomic nervous sys- tem. The reader will recall that this system has three divisions the cranial and sacral, separated by the sympathetic and that when the neurones of the mid-division meet in any organ the neurones of either of the end divisions, the influence of the two sets is antagonistic. As previously stated (p. 35), there is evidence that arrangements exist in the central nervous system for reciprocal innervation of these antagonistic divisions, just as there is reciprocal innervation of antagonistic skeletal muscles. The characteristic affective states mani- fested in the working of these three divisions have been described. Undoubtedly, these states have correspondents activities and inhibitions in the central neurones. The question now arises, are the states which appear in opposed divisions also in opposition? 267 268 BODILY CHANGES ANTAGONISM BETWEEN EMOTIONS EXPRESSED IN THE SYMPA- THETIC AND IN THE CRANIAL DIVISIONS OF THE AUTONOMIO SYSTEM The cranial autonomies, as already shown, is con- cerned with the quiet service of building up re- serves and fortifying the body against times of stress. Accompanying these functions are the relatively mild pleasures of sight and taste and smell of food. The possibility of existence of these gentle delights of eating and drinking and also of their physiological consequences is instantly abol- ished in the presence of emotions which activate the sympathetic division. The secretion of saliva, gastric juice, pancreatic juice and bile is stopped, and the motions of the stomach and intestines cease at once, both in man and in the lower animals, whenever pain, fear, rage, or other strong excite- ment is present in the organism. All these disturbances of digestion seem mere interruptions of the "normal" course of events unless the part they may play in adaptive reac- tions is considered. In discussing the operations of the sympathetic division, I pointed out that all the bodily changes which occur in the intense emo- tional states such as fear and fury occur as results of activity in this division, and are in the highest degree serviceable in the struggle for exist- ence likely to be precipitated when these emotions aroused. From this point of view these per- INTERRELATIONS OF EMOTIONS 269 turbations, which so readily seize and dominate the organs that in quiet times are commonly con- trolled by the cranial autonomic, are bodily reac- tions which may be of the utmost importance to life at times of critical emergency. Thus are the body's reserves the stored adrenin and the accumulated sugar called forth for instant service ; thus is the blood shifted to nerves and muscles that may have to bear the brunt of struggle ; thus is the heart set rapidly beating to speed the circulation ; and thus, also, are the activities of the digestive organs for the time abolished. Just as in war between nations the arts and industries which have brought wealth and contentment must suffer serious neglect or be wholly set aside both by the attacker and the at- tacked, and all the supplies and energies developed in the period of peace must be devoted to the pres- ent conflict; so, likewise, the functions which in quiet times establish and support the bodily re- serves are, in times of stress, instantly checked or completely stopped, and these reserves lavishly drawn upon to increase power in the attack and in the defense or flight.* It is, therefore, the natural antagonism between these two processes in the body between saving * One who permits fears, worries and anxieties to disturb the digestive processes when there is nothing to he done, is evidently allowing the body to go onto what we may regard as a "war footing," when there is no "war" to be waged, no fighting or struggle to be engaged in. 270 BODILY CHANGES and expenditure, between preparation and use, be- tween anabolism and catabolism and the corre- lated antagonism of central innervations, that un- derlie the antipathy between the emotional states which normally accompany the processes. The desire for food, the relish of eating it, all the pleasures of the table, are naught in the presence of anger or great anxiety. And of the two sorts of emotional states, those which manifest them- selves in the dominant division of the autonomic hold the field also in consciousness. ANTAGONISM BETWEEN EMOTIONS EXPRESSED IN THE SYMPA- THETIC AND IN THE SACRAL DIVISIONS OF THE AUTONOMIC SYSTEM The nervi erigentes are the part of the sacral autonomic in which the peculiar excitements of sex are expressed. As previously stated, these nerves are opposed by branches from the sympa- thetic division the division which is operated characteristically in the major emotions. The opposition in normal individuals between the emotional states which appear in these two antag- onistic divisions is most striking. Even in animals as low in the scale as birds, copulation is not per- formed "until every condition of circumstance and sentiment is fulfilled, until time, place and partner all are fit." 1 And among men the effect of fear or momentary anxiety or any intense emotional interest in causing inhibition of the act can be sup- INTEBKELATIONS OF EMOTIONS 271 ported by cases in the experience of any physician with extensive practice. Indeed, as Prince 2 has stated, "the suppression of the sexual instinct by conflict is one of the most notorious experiences of this kind in everyday life. This instinct cannot be excited during an attack of fear or anger, and even during moments of its excitation, if there is an invasion of another strong emotion the sexual instinct at once is repressed. Under these con- ditions, as with other instincts, even habitual excitants can no longer initiate the instinctive process." When the acme of excitement is approaching it is probable that the sympathetic division is also called into activity ; indeed, the completion of the process the contractions of the seminal vesicles and the prostate, and the subsidence of engorged tissues, all innervated by sympathetic filaments (see pp. 32, 33) may be due to the overwhelm- ing of sacral by sympathetic nervous discharges. As soon as this stage is reached the original feeling likewise has been dissipated. The other parts of the sacral division which supply the bladder and rectum are so nearly free from any emotional tone in their normal reflex functioning that it is unnecessary to consider them further with reference to emotional antagonisms. Mild affective states, such as worry and anxiety, can, to be sure, check the activity of the colon and 272 BODILY CHANGES thus cause constipation. 3 But the augmented activity of these parts (contraction of the bladder and rectum) in very intense periods of emotional stress, when the sympathetic division is strongly innervated, presents a problem of some difficulty. Possibly in such conditions the orderliness of the central arrangements is upset, just as it is after tetanus toxin or strychnine poisoning, and opposed innervations no longer discharge reciprocally, but simultaneously, and then the stronger member of the pair prevails. Only on such a basis, at pres- ent, can I offer any explanation for the activity and the supremacy of the sacral innervation of the bladder and distal colon when the sympathetic innervation is aroused, as, for example, in great fright. THE FUNCTION OP HUNGER A summary in few words of the chief functions typically performed or supported by each division of the autonomic would designate the cranial divi- sion as the upbuilder and restorer of the organic reserves, the sacral as the servant of racial contin- uity, and the sympathetic as the preserver of the in- dividual. Self-preservation is primary and essen- tial ; on that depends racial continuity, and for that all the resources of the organism are called forth. Analogously the sympathetic innervations, when they meet in organs innervated also by the cranial INTERRELATIONS OF EMOTIONS 273 and sacral divisions, almost without exception pre- dominate over their opponents. And analogously, also, the emotional states which are manifested in the sympathetic division and are characteristically much more intense than those manifested in the other divisions, readily assume ascendancy also in consciousness. It is obvious that extended action of the sym- pathetic division, abolishing those influences of the cranial division which are favorable to proper di- gestion and nutrition, might defeat its own ends. Interruption of the nutritional process for the sake of self-preservation through defense or attack can be only temporary; if the interruption were pro- longed, there might be serious danger to the vigor of the organism from failure to replenish the ex- hausted stores. The body does not have to depend on the return of a banished appetite, however, be- fore its need for restoration is attended to. There is a secondary and very insistent manner in which the requirement of food is expressed, and that is through the repeated demands of hunger. Unlike many other rhythmically repeated sen- sations, hunger is not one that anybody becomes ac- customed to and neglects because of its monotony. During the period of his confinement in the citadel of Magdeburg, the celebrated political adventurer Baron von Trenck 4 was allowed only a pound and a half of ammunition bread and a jug of water 274 BODILY CHANGES as his daily ration. "It is impossible for me to describe to my reader," he wrote in his memoirs, "the excess of tortures that during eleven months I endured from ravenous hunger. I could easily have devoured six pounds of bread every day ; and every twenty-four hours, after having received and swallowed my small portion, I continued as hungry as before I began, yet I was obliged to wait another twenty-four hours for a new morsel. . . . My tortures prevented sleep, and looking into futurity, the cruelty of my fate seemed to me, if possible, to increase, for I imagined that the pro^ longation of pangs like these was insupportable. God preserve every honest man from sufferings like mine! They were not to be endured by the most obdurate villain. Many have fasted three days, many have suffered want for a week or more, but certainly no one besides myself ever endured it in the same excess for eleven months ; some have supposed that to eat little might become habitual, but I have experienced the contrary. My hunger increased every day, and of all the trials of forti- tude my whole life has afforded, this eleven months was the most bitter."* *In all probability the continued experience of hunger pangs reported by Baron von Trenck was due to the re- peated eating of amounts of food too small to satisfy the bodily demand. The reader will recall that persons who for some time take no food whatever report that the disagreeable feelings are less intense or disappear after the third or fourth day (see p. 238). INTERRELATIONS OF EMOTIONS 27J Thus, although the taking of food may be set in abeyance at times of great excitement, and the bodily reserves fully mobilized, that phase of the organism's self-protecting adjustment is limited, and then hunger asserts itself as an agency im- periously demanding restoration of the depleted stores. THE SIMILARITY OF VISCERAL EFFECTS IN DIFFERENT STRONG EMOTIONS AND SUGGESTIONS AS TO ITS PSYCHOLOGICAL SIGNIFICANCE The dominant emotions which we have been con- sidering as characteristically expressed in the sympathetic division of the autonomic system are fear and rage. These two emotions ate not unlike. As James 5 has indicated, "Fear is a reaction aroused by the same objects that arouse ferocity. . . . We both fear and wish to kill anything that may kill us ; and the question which of the two impulses we shall follow is usually decided by some one of those collateral circumstances of the par- ticular case, to be moved by which is the mark of superior mental natures." The cornering of an animal when in the headlong flight of fear may suddenly turn the fear to fury and the flight to a fighting in which all the strength of desperation is displayed. Furthermore, these dominant emotions are states into which many other commonly milder affective states may be suddenly transformed. As McDou- 276 BODILY CHANGES gall 6 has pointed out, all instinctive impulses when met with opposition or obstruction give place to, or are complicated by, the pugnacious or com- bative impulse directed against the source of the obstruction. A dog will bristle at any attempt to take away his food, males will fight furiously when provoked by interference with the satisfaction of the sexual impulse, a man will forget the conven- tions and turn hot for combat when there is impu- tation against his honor, and a mother all gentle with maternal devotion is stung to quick resent- ment and will make a fierce display of her com- bative resources, if anyone intentionally injures her child. In these instances of thwarted or dis- turbed instinctive acts the emotional accompani- ments such as the satisfaction of food and of sexual affection, the feeling of self -pride, and the tender love of a parent are whirled suddenly into anger. And anger in one is likely to provoke anger or fear in the other who for the moment is the object of the strong feeling of antagonism. Anger is the emotion preeminently serviceable for the display of power, and fear is often its counterpart. The visceral changes which accompany fear and rage are the result of discharges by way of sym- pathetic neurones. It will be recalled that these neurones are arranged for diffuse rather than for narrowly directed effects. So far as these two INTERRELATIONS OF EMOTIONS 277 quite different emotions are concerned, present physiological evidence indicates that differences in visceral accompaniments* are not noteworthy for example, either fear or rage stops gastric se- cretion (see pp. 10, 11). There is, indeed, obvious reason why the visceral changes in fear and rage should not be different, but rather, why they should be alike. As already pointed out, these emotions accompany organic preparations for action, and just because the conditions which evoke them are likely to result in flight or conflict (either one requiring perhaps the utmost struggle), the bodily needs in either response are precisely the same. In discussing the functioning of the sympathetic division I pointed out that it was roused to ac- tivity not only in fear and rage, but also in pain. The machinery of this division likewise is oper- ated wholly or partially in emotions which are usually mild such as joy and sorrow and disgust 'Obvious vascular differences, as pallor or flushing of the face, are of little significance. With increase of blood pres- sure from vasocoustriction, pallor might result from action of the constrictors in the face, or flushing might result because constrictors elsewhere, as, for example, in the abdomen, raised the pressure so high that facial constrictors are overcome. Such, apparently, is the effect of adrenin already described (see p. 107)\ Or the flushing might occur from local vasodila- tion. That very different emotional states may have the same vascular accompaniments was noted by Darwin (The Expres- sion of Emotions in Man and Animals, New York, 1905), who mentioned the pallor of rage (p. 74) and also of terror (P. 77). 278 BODILY CHANGES when they become sufficiently intense. Thus, for instance, the normal course of digestion may be stopped or quite reversed in a variety of these emotional states. Darwin 7 reports the case of a young man who on hearing that a fortune had just been left him, became pale, then exhilarated, and after various expressions of joyous feeling vomited the half- digested contents of his stomach. Miiller 8 has described the case of a young woman whose lover had broken the engagement of marriage. She wept in bitter sorrow for several days, and during that time vomited whatever food she took. And Burton, 9 in his Anatomy of Melancholy, gives the following instance of the effect of disgust : "A gentlewoman of the same city saw a fat hog cut up, when the entrails were opened, and a noisome savour offended her nose, she much misliked, and would not longer abide; a physician in presence told her, as that hog, so was she, full of filthy ex- crements, and aggravated the matter by some other loathsome instances, insomuch this nice gen- tlewoman apprehended it so deeply that she fell forthwith a vomiting, was so mightily distempered in mind and body, that with all his art and persua- sion, for some months after, he could not restore her to herself again, she could not forget or remove the object out of her sight." In these three cases, of intense joy, intense sor- INTERRELATIONS OF EMOTIONS 279 row and intense disgust, the influence of the cran- ial division of the autonomic has been overcome, digestion has ceased, and the stagnant gastric contents by reflexes in striated muscles have been violently discharged. The extent to which under such circumstances other effects of sympathetic impulses may be manifested, has not, so far as I know, been ascertained. From the evidence just given it appears that any high degree of excitement in the central nerv- ous system, whether felt as anger, terror, pain, anxiety, joy, grief or deep disgust, is likely to break over the threshold of the sympathetic divi- sion and disturb the functions of all the organs which that division innervates. It may be that there is advantage in the readiness with which these widely different emotional conditions can ex- press themselves in this one division, for, as has been shown (see p. 276), occasions may arise when these milder emotions are suddenly transmuted into the naturally intense types (as fright and fury) which normally activate this division; and if the less intense can also influence it, the physio- logical aspect of the transmutation is already par- tially accomplished. If various strong emotions can thus be expressed in the diffused activities of a single division of the autonomic the division which accelerates the heart, inhibits the movements of the stomach and 280 BODILY CHANGES intestines, contracts the blood vessels, erects the hairs, liberates sugar, and discharges adrenin it would appear that the bodily conditions which have been assumed, by some psychologists, to distin- guish emotions from one another must be sought for elsewhere than in the viscera. We do not "feel sorry because we cry/' as James contended, but we cry because when we are sorry or overjoyed or violently angry or full of tender affection when any one of these diverse emotional states is present there are nervous discharges by sympathetic channels to various viscera, including the lachry- mal glands. In terror and rage and intense elation, for example, the responses in the viscera seem too uniform to offer a satisfactory means of distin- guishing states which, in man at least, are very different in subjective quality. For this reason I am inclined to urge that the visceral changes mere- ly contribute to an emotional complex more or less indefinite, but still pertinent, feelings of disturb- ance in organs of which we are not usually con- scious. This view that the differential features of emo- tions are not to be traced to the viscera is in accord with the experimental results of Sherrington, 10 who has demonstrated that emotional responses occur in dogs in which practically all the main vis- cera and the great bulk of skeletal muscle have been removed from subjection to and from influ- INTERRELATIONS OF EMOTIONS 281 ence upon the brain, by severance of the vagus nerves and the spinal cord. In these animals no alteration whatever was noticed in the occurrence, under appropriate circumstances, of characteristic expressions of voice and features, indicating anger, delight or fear. The argument that these expres- sions may have been previously established by af- ferent impulses from excited viscera was met by noting that a puppy only nine weeks old also con- tinued to exhibit the signs of emotional excitement after the brain was disconnected from all the body except the head and shoulders. Evidence from uni- formity of visceral response and evidence from ex- clusion of the viscera are harmonious, therefore, in minimizing visceral factors as the source of differ- ences in emotional states.* If these differences are due to other than vis- ceral changes, why is it not always possible by vol- untary innervations to produce emotions ? We can laugh and cry and tremble. But forced laughter does not bring happiness, nor forced sobbing sor- row, and the trembling from cold rouses neither anger nor fear. The muscle positions and tensions are there, but the experiencing of such bodily changes does not seem even approximately to rouse * The paucity of afferent fibres in the autonomic system, and the probability of an extremely low degree of sensitive- ness in the viscera (for evidence, see Cannon : The Mechan- ical Factors of Digestion, London, 1911, p. 202), likewise sup- port this conclusion. 282 BODILY CHANGES an emotion in us. Voluntary assumption of an at- titude seems to leave out the "feeling." It is prob- able, however, that no attitude which we can assume has all the elements in it which appear in the com- plete response to a stirring situation. But is not this because the natural response is a pattern reaction, like inborn reflexes of low order, such as sneez- ing, in which impulses flash through peculiarly co- operating neurone groups of the central system, suddenly, unexpectedly, and in a manner not ex- actly reproducible by volition, and thus they throw the skeletal muscles into peculiar attitudes and, if sufficiently intense, rush out in diffuse discharges that cause tremors and visceral perturbations? The typical facial and bodily expressions, automat- ically assumed in different emotions, indicate tho discharge of peculiar groupings of neurones in the several affective states. That these responses oc- cur instantly and spontaneously when the appro- priate "situation," actual or vividly imagined, is present, shows that they are ingrained in the nerv- ous organization. At least one such pattern, that of anger, persists after removal of the cerebral hemispheres the decorticated dog, by growling and biting when handled, has the appearance of being enraged; 11 the decerebrate cat, when vig- orously stimulated, retracts its lips and tongue, stares with dilated pupils, snarls and snaps its jaws. 12 On the other hand, stroking the hair, INTERRELATIONS OF EMOTIONS 283 whistling and gently calling to produce a pleased attitude, or yelling to produce fright, have not the slightest effect in evoking from the decorticated dog signs of joy and affection or of fear, nor does the animal manifest any sexual feeling. The ab- sence of bodily indications of these emotions is quite as significant as the presence of the signs of anger. For since expressions of anger can persist without the cerebral cortex, there is little reason why the complexes of other emotional expressions, if their "machinery" exists below the cortex, should not also be elicitable. That they are not elicitable suggests that they require a more elaborately or- ganized grouping of neurones than does anger possibly what the cortex, or the cortex in combi- nation with basal ganglia, would provide. The contrast between the brevity of the "pseudo- affective reactions" in the decerebrate cat, though the viscera are still connected with the central nervous system, and the normal duration of emo- tional expression in the dog with the body sepa- rated from the head region, has been used by Sher- rington to weigh the importance of the visceral and other factors. And the evidence which I have given above, as well as that which he has offered, favor? the view that the viscera are relatively unimpor- tant in an emotional complex, especially in con- tributing differential features. 284 BODILY CHANGES REFERENCES 1 James : Principles of Psychology, New York, 1905, i, p. 22. 2 Prince: The Unconscious, New York, 1914, p. 456. 8 Hertz: Constipation and Allied Intestinal Disorders, London, 1909, p. 81. 4 v. Trenck: Merkwiirdige Lebensgeschichte, Berlin, 1787, p. 195. 5 James, Loc. cit. t p. 415. 6 McDougall : Introduction to Social Psychology, London, 1908, p. 72. 7 Darwin : Loc. cit., p. 76. 8 Miiller : Deutsches Archiv f iir klinische Medicin, 1907, Ixxxix, p. 434. 9 Burton : The Anatomy of Melancholy (first published in 1621), London, 1886, p. 443. 10 Sherrington : Proceedings of the Royal Society, 1900, Ixvi, p. 397. 11 Goltz : Archiv f iir die gesammte Physiologie, 1892, li, p. 577. 12 Wood worth and Sherrington: Journal of Physiology, 1904, xxxi, p. 234. CHAPTEE XV ALTERNATIVE SATISFACTIONS FOE THE FIGHTING EMOTIONS The uniformity of visceral responses when al- most any feelings grow very intense, and under such conditions the identity of these responses with those characteristically aroused in the bel- ligerent emotion of anger or rage and its counter- part, fear, offer interesting possibilities of trans- formation and substitution. This is especially true in the activities of human beings. And be- cause men have devised such terribly ingenious and destructive modes of expressing these feelings in war, an inquiry into the basis for possible substi- tution seems not out of place. SUPPORT FOR THE MILITARIST ESTIMATE OF THE STRENGTH OF THE FIGHTING EMOTIONS AND INSTINCTS The business of killing and of avoiding death has been one of the primary interests of living beings throughout their long history on the earth. It is in the highest degree natural that feelings of 285 286 BODILY CHANGES hostility often burn with fierce intensity, and then, with astonishing suddenness, that all the powers of the body are called into action for the strength of the feelings and the quickness of the response measure the chances of survival in a struggle where the issue may be life or death. These are the powerful emotions and the deeply ingrained instinctive reactions which invariably precede com- bat. They are the emotions and instincts that sometimes seize upon individuals in groups and spread like wildfire into larger and larger aggre- gations of men, until entire populations are shout- ing and clamoring for war. To whatever extent military plans are successful in devising a vast machine for attack or defense, the energies that make the machine go are found, in the last analysis, in human beings who, when the time for action comes, are animated by these surging elemental tendencies which assume control of their conduct and send them madly into conflict. The strength of the fighting instinct in man has been one of the main arguments used by the mili- tarists in support of preparation for international strife. They point to the historical fact that even among highly civilized peoples scarcely a decade passes without a kindling of the martial emo- tions, which explode in actual warfare. Such fight- ing, they say, is inevitable the manifestation of "biological law" and, so long as human nature FIGHTING EMOTIONS 287 remains unchanged, decision by battle must be re- sorted to. They urge, furthermore, that in war and in the preparations for war important phys- ical qualities sturdiness, hardihood, and strength for valorous deeds are given peculiarly favorable opportunities for development, and that if these op- portunities are lacking, lusty youth will give place to weaklings and mollycoddles. In addition the militarists say that war benefits mankind by its moral effects. Without war nations become effete, their ideals become tarnished, the people sink into self-indulgence, their wills weaken and soften in luxury. War, on the contrary, disciplines charac- ter, it sobers men, it teaches them to be brave and patient, it renews a true order of values, and its de- mand for the supreme sacrifice of life brings forth in thousands an eager response that is the crown- ing glory of the human spirit. As the inevitable expression of a deep-rooted instinct, therefore, and as a unique means of developing desirable physical and moral qualities, war is claimed by the mili- tarists to be a natural necessity. 1 The militarist contention that the fighting in- stinct is firmly fixed in human nature receives strong confirmation in the results of our re- searches. Survival has been decided by the grim law of mortal conflict, and the mechanism for ren- dering the body more competent in conflict has been revealed in earlier chapters as extraordinarily per- 288 BODILY CHANGES feet and complete. Moreover, the physiological provisions for fierce struggle are found not only in the bodies of lower animals, that must hunt and kill in order to live, but also in human beings. Since this remarkable mechanism is present, and through countless generations has served the fun- damentally important purpose of giving momen- tous aid in the struggle for existence, the mili- tarists might properly argue that, as with other physiological processes, bodily harmony would be promoted by its exercise. Indeed, they might account for the periodic outburst of belligerent feelings by assuming that these natural aptitudes require occasional satisfaction.* GROWING OPPOSITION TO THE FIGHTING EMOTIONS AND INSTINCTS AS DISPLAYED IN WAR In spite of the teachings of history that wars have not grown fewer, and in spite of the militarist argument that war is a means of purging mankind of its sordid vices, and renewing instead the no- blest virtues, the conclusion that the resort to arms is unavoidable and desirable is nowadays being strongly contested. The militarists show only *Mr. Graham Wallas has made the interesting sugges- tion (The Great Society, New York, 1914, p. 66) that nerv- ous strain and restlessness due to baulked disposition" may result from the absence of circumstances which would call the emotional responses into action. And he cites Aristotle's theory that pent passions may be released by represented tragedy and by music. FIGHTING EMOTIONS 289 part of the picture. No large acquaintance with the character of warfare is necessary to prove that when elemental anger, hate and fear prevail, civilized conventions are abandoned and the most savage instincts determine conduct. Homes are looted and burned, women and children are abominably treated, and many innocents are murdered outright or starved to death. No bland argument for the preservation of the manly virtues can palliate such barbarities. Even when fighting men are held within the rules, the de- vices for killing and injuring are now made so perfect by devilish ingenuity that by the pulling of a trigger one man can in a few seconds mow down scores of his fellow-creatures and send them writhing to agony or death. War has become too horrible; it is conducted on too stupendous a scale of carnage and expenditure; it destroys too many of the treasured achievements of the race; it interferes too greatly with consecrated efforts to benefit all mankind by discovery and invention ; it involves too much suffering among peoples not di- rectly concerned in the struggle ; it is too vastly at variance with the methods of fair dealing that have been established between man and man ; the human family has become too closely knit to allow some of its members to bring upon themselves and all the rest poverty and distress and a long heritage of bitter hatred and resolution to seek revenge. 290 BODILY CHANGES All these reasons for hostility to war imply a thwarting of strong desires in men desires for family happiness, devotion to beauty and to schol- arship, passion for social justice, hopes of lessen- ing poverty and disease. As was pointed out in the previous chapter, the feeling of hostility has no definite object to awaken it. It is roused when there is opposition to what we ardently wish to get. And because war brings conditions which frustrate many kinds of eagerly sought purposes, war has roused in men a hostility against itself. There is then a war against war, a willingness to fight against monstrous carnage and destruction, that grows in intensity with every war that is waged. THE DESIRABILITY OF PRESERVING THE MARTIAL VIRTUES Although there is increasing opposition to the display of the fighting emotions and instincts in war, nevertheless the admirable moral and phys- ical qualities, claimed by the militarists to be the unique products of war, are too valuable to be lost. As McDougall 2 has indicated, when the life of ideas becomes richer, and the means we take to overcome obstructions to our efforts more refined and complex, the instinct to fight ceases to express itself in its crude natural manner, save when most intensely excited, and becomes rather a source of increased energy of action towards the end set by any other instinct ; the energy of its impulses adds FIGHTING EMOTIONS 291 itself to and reenf orces that of other impulses and so helps us to overcome our difficulties. In this lies its great value for civilized man. A man de- void of the pugnacious instinct would not only be incapable of anger, but would lack this great source of reserve energy which is called into play in most of us by any difficulty in our path. Thus the very efficiency of a war against war, as well as struggle against other evils that beset civil- ized society, rests on the preservation and use of aggressive feeling and the instinct to attack. From this point of view the insistence by the militarists that we must accept human nature as we find it, and that the attempt to change it is foolish, seems a more justifiable attitude than that of the paci- fists who belittle the fighting qualities and urge that changing them is a relatively simple process. We should not wish them changed. Even if in the war against war a means should be established of securing international justice, and if through co- operative action the decrees of justice were en- forced, so that the occasions which would arouse belligerent emotions and instincts were much re- duced, there would still remain the need of recog- nizing their elemental character and their possible usefulness to society. What is needed is not a suppression of these capacities to feel and act, but their diversion into other channels where they may have satisfactory expression. 292 BODILY CHANGES MORAL SUBSTITUTES FOR WARFAU "We must make new energies and hardihoods continue the manliness to which the military mind so faithfully clings. Martial virtues must be the enduring cement; intrepidity, contempt of soft- ness, surrender of private interest, obedience to command, must still remain the rock upon which states are built." Thus wrote William James 3 in proposing a "moral equivalent for war." This, he suggested, should consist of such required serv- ice in the hard and difficult occupations as would take the childishness and superciliousness out of our youth and give them soberer ideas and health- ier sympathies with their fellow-men. He con- ceived that by proper direction of its education a people should become as proud of the attainment by the nation of superiority in any ideal respect as it would be if the nation were victorious in war. "The martial type of character," he declared, "can be bred without war. Strenuous honor and disin- terestedness abound elsewhere. Priests and medi- cal men are in a fashion educated to it, and we should all feel some degree of it imperative if we were conscious of our work as an obligatory serv- ice to the state. We should be owned, as soldiers are by the army, and our pride would rise ac- cordingly. We could be poor, then, without humiliation, as army officers now are. The only thing needed ^eeforth is to inflame the civic FIGHTING EMOTIONS 293 temper as past history has inflamed the military temper." Similar ideas have been expressed by others. 4 It has been pointed out that the great war of man- kind is that against pain, disease, poverty and sin ; that the real heroes are not those who squander hu- man strength and courage in fighting one another, but those who fight for man against these his eter- nal foes. War of man against man, in this view, becomes dissension in the ranks, permitting the common enemies to strike their most telling blows. These moral considerations, however, are apart from the main intent of our discussion. Our ear- lier inquiry confirmed the belief that the fighting emotions are firmly rooted in our natures, and showed that these emotions are intimately asso- ciated with provisions for physical exertion. It is particularly in this aspect of the discussion of substitutes for war that these studies have sig- nificance. PHYSICAL SUBSTITUTES FOR WARFARE The idealization of the state and the devotion of service to social welfare, which have been sug- gested as moral substitutes for military loyalty, leave unanswered the claims of the militarists that in war and in preparations for war oppor- tunities are offered which are peculiarly favorable to the development of important physical qualities 294 BODILY CHANGES bodily vigor, sturdiness, and ability to with- stand all manner of hardships. In the evidence previously presented, it seems to me there was a suggestion that offers a perti- nent alternative to these claims. "When the body goes onto what we have called a war footing, the physiological changes that suddenly occur are all adapted to the putting forth of supreme mus- cular and nervous efforts. That was what primi- tive battle consisted of, through countless myriads of generations a fierce physical contest of beast with beast, and of man with man. Such contests, attended as they were by the thrill of unpredict- able incidents, and satisfying completely the lust of combat, are to be contrasted with the dull grind in preparation for modern war, the monotonous regularity of subservience, the substitution every- where of mechanism for muscle, and often the attack on an enemy who lies wholly unseen.* As *Lord Wolseley, while commander-in-chief of the English forces, in 1897, secured sanction for not displaying" the regi- mental colors in battle. "It would be madness and a crime," he declared, "to order any soldier to carry colors into action in the future. You might quite as well order him to be as- sassinated. We have had most reluctantly to abandon a practice to which we attached great importance, and which, under past and gone conditions of fighting, was invaluable in keeping alive the regimental spirit upon which our British troops depended so much." All war has been transformed by the invention of the far-reaching and fate-dealing rifle and automatic gun, with which an enemy kills, whose face is not even seen. War is almost reduced to a mechanical inter- FIGHTING EMOTIONS 295 Wallas with nice irony has remarked, "The gods in Valhalla would hardly choose the organization of modern lines of military communication, as they chose the play of sword and spear, to be the most exquisite employment of eternity." While it is true that physical strength can be developed by any form of hard labor, as, for example, by sawing wood or digging ditches, such labor does not stimulate quickness, alertness, and resourcefulness in bodily action. Nor does it give any occasion for use of the emotional mechanism for reenforcement. If this mechanism, like other physiological arrangements, is present in the body for use and previous discussion leaves little change of volleys and salvoes, and to the intermittent fire of rifles and machine guns, with short rushes at the last, in which there is no place for the dignity and grace of the antique battle of the standard. (See London Times, July 31, 1897, p. 12.) T. F. Millard, the well-known correspondent of the Russo- Japanese War, wrote as follows of the characteristics of present day conflicts: "A large part of modern war is on too great a scale to give much opportunity for individual initiative. Soldiers can rarely tell what is going on in their immediate vicinity. They cannot always see the enemy they are firing at, and where they can see the object of their fire such an important matter as range and even direction can- not be left to them. . . . Troops are clothed so much alike nowadays that it is very difficult to distinguish friend from foe at five hundred yards, and large bodies of troops rarely get that close to each other in modern war while there is light enough to see clearly. . . . Battery officers simply see that their guns are handled according to instructions. They 296 BODILY CHANGES doubt of that then as a means of exercising it and, in addition, satisfying the strong instinct for competitive testing of strength and physical skill, some activity more enlivening than monotonous gymnastics and ordered marching is required. In many respects strenuous athletic rivalries present, better than modern military service, the conditions for which the militarists argue, the conditions for which the body spontaneously pre- pares when the passion for fighting prevails. As explained in an earlier chapter, in competitive sports the elemental factors are retained man is again pitted against man, and all the resources of the body are summoned in the eager struggle regulate the time, speed, objective and range as ordered. . . . The effects of the fire are observed by officers appointed to that duty, stationed at various parts of the field, often miles and miles apart, and who are in constant communication with the chief of artillery by telephone." (See Scribner's Magazine, 1905, xxxvii, pp. 64, 66.) The testimony of a captain of a German battery engaged against the French and English in 1914, supports the forego- ing claims. He is reported as saying : "We shoot over those tree tops yonder in accordance with directions for range and distance which come from somewhere else over a field tele- phone, but we never see the men at whom we are firing. They fire back without seeing us, and sometimes their shells fall short or go beyond us, and sometimes they fall among us and kill and wound a few of us. Thus it goes on day after day. I have not with my own eyes seen a Frenchman or an Englishman unless he was a prisoner. It is not so much pleasure fighting like this." (See Philadelphia Saturday Evening Post, December 26, 1914, p. 37.) FIGHTING EMOTIONS 297 for victory. And because, under such circum- stances, the same physiological alterations occur that occur in anticipation of mortal combat, the belligerent emotions and instincts, so far as their bodily manifestations are concerned, are thereby given complete satisfaction. THE SIGNIFICANCE OF INTERNATIONAL ATHLETIC COMPETITIONS For reasons offered above, I venture to lay em- phasis on a suggestion, which has been made before by others, that the promotion of great inter- national athletic contests, such as the Olympic games, would do for our young men much that is now claimed as peculiar to the values of military discipline. The substitution of athletic rivalries for battle is not unknown. In the Philippine Isl- ands, according to Worcester, 5 there were no athletics before the American occupation. The natives soon learned games from the soldiers. And when the sports reached such development that competition between towns and provinces was possible, they began to arouse the liveliest enthu- siasm among the people. The physical develop- ment of the participants has been greatly stimu- lated, the spirit of fair play and sportsmanship, formerly lacking, has sprung into existence in every section of the Islands, and the annual meets between athletic teams from various provinces are recognized as promoting a general and friendly 298 BODILY CHANGES understanding among the different Filipino tribes. The fierce Igarots of Bontoc, once constantly at war with neighboring tribes, now show their prow- ess not in head-hunting, but in baseball, wrestling, and the tug-of-war.* Is it unreasonable to expect that what has hap- pened in the Philippine Islands might, by proper education and suggestion, happen elsewhere in the world! Certainly the interest in athletic contests is no slight and transient interest. At the time of a great war we know that news of the games is fully as much demanded as news of the war. Already in the United States, without special stimulation, the number of young men engaged in athletic training is estimated as equal to the num- ber in the standing army. And in England, belief in the efficacy of athletics as a means of promoting hardihood and readiness to face stern hazards has found expression in the phrase that England's battles have been won on the playing fields of Kugby and of Eton. With the further promotion of international contests the influence of competi- tive sports is likely to increase rather than lessen. Within national boundaries emulation is sure to stimulate extensively such games as will bring forth the best representative athletes that the coun- * It is reported that when these warriors first appeared at the games, each brought his spear, which he drove into the ground beside him, ready for use. As the nature of the new rivalries became known, the spears were left behind* FIGHTING EMOTIONS 299 try can produce. In one of the high-spirited Eu- ropean nations, which made a poor showing at the last Olympic meet, thousands of young men began training for the next meet, under a director im- ported from the nation that had made the highest records. Training for athletic contests is quite as likely to enure young men to physical hardship and fatigue, is quite as conducive to the development of bodily vigor, the attainment of alertness and skill and the practice of self-restraint, as is army life with its traditional associations and easy li- cense. It may be urged, however, that an essential element is lacking in all this discussion the so- bering possibility that in war the supreme sur- render of life itself may be required. Death for one's country is indeed glorious. But the argu- ment that being killed is desirable has little to commend it. When the strongest and sturdiest are constantly chosen to be fed to the engines of anni- hilation, the race is more likely to lose greater values than it gains from the spectacle of self- sacrifice, however perfect that may be. Are there not advantages in the conditions of great athletic rivalries that may compensate for war's most aus- tere demand? The race of hardy men, to secure which the militarists urge war, is much more likely to result from the honoring and preserving of vigorous men in their vigor than it is from the 300 BODILY CHANGES systematic selection of such men to be destroyed in their youth. There are other aspects of international games which strongly commend them as an alternative to the pursuit of military discipline. The high standards of honor and fairness in sport ; its un- failing revelation of excellence without distinc- tions of class, wealth, race or color; the ease with which it becomes an expression of the natural feelings of patriotism; the respect which victory and pluckily borne defeat inspire in competitors and spectators alike; the extension of acquaint- ance and understanding which follows from friendly and magnanimous rivalry among strong men who come together from the ends of the earth each of these admirable features of athletic con- tests between nations might be enlarged upon. But, as intimated before, these moral considera- tions must be left without further mention, as being irrelevant to the physiological processes with which we are dealing. We are concerned with the question of exercis- ing the fighting instinct and thus assuring the physical welfare of the race. The race must de- generate, the militarists say, if this instinct is not allowed to express itself in war. This declar- ation we are in a position to deny, for the evi- dence is perfectly clean-cut that the aggressive instincts, which through aeons of racial experi- FIGHTING EMOTIONS 301 ence have naturally and spontaneously developed vigor and resourcefulness in the body, are invited by elemental emotions, and that through these emotions energies are released which are highly useful to great physical effort. No stupid routine of drill, or any other deadening procedure, will call these energizing mechanisms into activity. War and the preparations for war nowadays have become too machine-like to serve as the best means of preserving and disciplining these forces. The exhilarating swing and tug and quick thrust of the big limb muscles have largely vanished. Pressing an electric contact or bending the trigger finger is a movement altogether too trifling. If, then, natural feelings must be expressed, if the fight- ing functions of the body must be exercised, how much better that these satisfactions be found in natural rather than in artificial actions, how much more reasonable that men should struggle for victory in the ancient ways, one against an- other, body and spirit, as in the great games. REFERENCES 1 See Angell : The Great Illusion, New York and London, 1913, pp. 159-164. 2 McDougall : Introduction to Social Psychology, London, 1908, p. 61. 8 James : Memories and Studies, New York, 1911, p. 287. * See Perry:: The Moral Economy, New York, 1909, p. 32; and Drake : Problems of Conduct, Boston, 1914, p. 317. 5 Worcester : The Philippines, Past and Present, New York, 1914, ii, pp. 515, 578. A LIST OF PUBLISHED RESEARCHES FROM THE PHYSIOLOGICAL LABORATORY IN HARVARD UNIVERSITY, ON WHICH THE PRES- ENT ACCOUNT IS BASED. 1. The Influence of Emotional States on the Functions of the Alimentary Canal. By W. B. Cannon. American Jour- nal of the Medical Sciences, 1909, cxxxvii, pp. 480-487. 2. Emotional Stimulation of Adrenal Secretion. By W. B. Cannon and D. de la Paz. American Journal of Physiology, 1911, xxviii, pp. 64-70. 3. The Effects of Asphyxia, Hyperpncea, and Sensory Stimulation on Adrenal Secretion. By W. B. Cannon and R. G. Hoskins. Ibid., 1911, xxix, pp. 274-279. 4. Emotional Glycosuria. By W. B. Cannon, A. T. Shohl and W. S. Wright. Ibid., 1911, xxix, pp. 280-287. 5. A Consideration of Some Biological Tests for Epi- nephrin. By R. G. Hoskins. Journal of Pharmacology and Experimental Therapeutics, 1911, iii, pp. 93-99. 6. The Sthenic Effect of Epinephriii upon Intestine. By R. G. Hoskins. American Journal of Physiology, 1912, xxix, pp. 363-366. 7. An Explanation of Hunger. By W. B. Cannon and A. L. Washburn. Ibid., 1912, xxix, pp. 441-454. 8. A New Colorimetric Method for the Determination of Epinephrin. By O. Folin, W. B. Cannon and W. Denis. Journal of Biological Chemistry, 1913, xiii, pp. 477-483. 9. The Depressor Effect of Adrenalin on Arterial Pressure. By W. B. Cannon and Henry Lyman, American Journal of Physiology, 1913, xxxi, pp. 376-398. 302 PUBLISHED EESEAECHES 303 10. The Effect of Adrenal Secretion on Muscular Fatigue. By W. B. Cannon and L. B. Nice. Ibid., 1913, xxxii, pp. 44-60. 11. Fatigue as Affected by Changes of Arterial Pressure. By C. M. Gruber. Ibid., 1913, xxxii, pp. 222-229. 12. The Threshold Stimulus as Affected by Fatigue and Subsequent Rest. By C. M. Gruber. Ibid., 1913, xxxii, pp. 438-449. 13. The Fatigue Threshold as Affected by Adrenalin and by Increased Arterial Pressure. By C. M. Gruber. Ibid., 1914, xxxiii, pp. 335-355. 14. The Emergency Function of the Adrenal Medulla in Pain and the Major Emotions. By W. B. Cannon. Ibid., 1914, xxxiii, pp. 356-372. 15. The Relation of Adrenalin to Curare and Fatigue in Normal and Dcnervated Muscles. By C. M. Gruber. Ibid., 1914, xxxiv, pp. 89-96. 16. The Graphic Method of Recording Coagulation. By W. B. Cannon and W. L. Mendenhall. Ibid*, 1914, xxxiv, pp. 225-231. 17. The Hastening or Retarding of Coagulation by Adrenalin Injections. By W. B. Cannon and Horace Gray. Ibid., 1914, xxxiv, pp. 232-242. 18. The Hastening of Coagulation by Stimulating the Splanchnic Nerves. By W. B. Cannon and W. L. Menden- hall. Ibid., 1914, xxxiv, pp. 243-250. 19. The Hastening of Coagulation in Pain and Emotional Excitement. By W. B. Cannon and W. L. Mendenhall. Ibid. f 1914, xxxiv, pp. 251-261. 20. The Interrelations of Emotions as Suggested by Recent Physiological Researches. By W. B. Cannon. American Journal of Psychology, 1914, xxv, pp. 256-282. 21. The Isolated Heart as an Indicator of Adrenal Secretion Induced by Pain, Asphyxia and Excitement By W. B. Cannon. American Journal of Physiology, 1919, 1, pp. ?. INDEX Adrenal extract: effect of, on muscular contraction, 82. Adrenal glands: nerve sup- ply of, 37; stimulated in emotion, 52-59, 62-63 ; stimulated in pain, 59-62, 63; in relation to blood sugar, 77; removal of, causes muscular weakness, 81 ; secretion of, improves contraction of fatigued muscle, 92; variations in adrenin content of, 171; latent period of, when splanclmics stimulated, 188; amount of secretion from, when splanchnics stimulated, 198 ; fatigue of, 199; stimulated by as- phyxia, 206-208. Adrenin : secreted by adre- nal glands, 36; action of, identical with sympathetic impulses, 37, 64; secretion of, by splanchnic stimula- tion, 41-43; secreted in emotional excitement, 44, 52-59; method of testing for, in blood, 47-50; se- creted in emotion, 52-59, 62-63 ; disappearance of, from blood, 58 ; secreted in pain, 59-62, 63; effects of, when injected into body, 64-65; effect of, on dis- tribution of blood in the body, 107; quickly restores fatigued muscle to normal irritability, 119-123 ; specific in its restorative action, 124-128; as an antidote to muscular metabolites, 129; restores fatigued denerv- ated muscle to normal irri- tability, 130; point of ac- tion of, in muscle, 128-133; antagonistic to curare, 132; induces rapid coagulation of blood, 136, 147 ff.; not the direct cause of rapid coagulation, 156-158; fails to shorten coagulation time in absence of intestines and liver, 157-158; vari- able amount of, in adrenal glands, 171 ; emergency functions of, 185 ff. ; util- ity of, in bettering the con- traction of fatigued mus- cle, 194-195; not a check to use of sugar in the body, 197, 199; amount of, se- creted when splanchnics stimulated, 198; a condition for increase of blood sugar, 199; stimulates the heart, 191, 201 ; dilates the bron- chioles, 204; secretion of, increased in asphyxia, 206- 208. Amyl nitrite: effect of, on contraction of fatigued muscle, 126. 305 306. INDEX Anger i associated with ac- tion, 188 ; energizing influ- ence of, 216. Antagonisms : autonomic, 34 ; in relation to emotions, 38 ; between cranial and sym- pathetic divisions, 268-270; between sacral and sympa- thetic divisions, 270-272. Appetite : compared with hunger,. 233, 235; opera- tion of, after section of vagus and splanchnic nerves, 240. Arterial blood pressure: in- creased in excitement, 95; artificial methods of in- creasing, 97; influence of different heights of, on fatigue, 97-102; influence of increase of, on fa- tigue, 97-102 ; influence of decrease of, on fa- tigue, 102 - 104; the "critical region" in de- creasing, 104; explanation of effects on fatigued mus- cle, of varying, 104-106; value of increased, in pain and emotion, 106. Arteries: innervation of, 26. Asphyxia: increases adrenal secretion, 206-208 ; in- creases sugar in blood, 209. Athletes : glycosuria of, after games, 75. Autonomic nervous system: three divisions of, 25; ar- rangement of sympathetic division of, 26-29 ; arrange- ment of cranial and sacral divisions of, 29-30 ; general functions of cranial di- vision of, 30-32; general functions of sacral division of, 32-34; antagonism be- tween sympathetic and cranial-sacral divisions of, 34-36 ; identity of action of sympathetic division of, and adrenal secretion, 36- 38 ; antagonisms between emotions expressed in, 268- 272. Behavior : biological explana- tion of, 2. Bile: flow of, inhibited by excitement, 13. Bladder: innervation of, 27, 32; effects of emotions on, 33. Blood: method of obtaining, for test for adrenin, 45-46 ; method of testing, for adrenin, 47-50; sugar in, 66, 73-74; distribution of, as affected by adrenin, pain and excitement, 107-108, 200; functions of, 135; rapid coagulation of, by adrenin, 136 ff. ; drawing of, for testing coagulation time, 140-142; treatment of, in testing coagulation time, 142-145; faster co- agulation of, after subcu- taneous injections of adre- nin, 147-150, and after in- travenous injections, 150- 156; oscillations in the rate of coagulation of, 155 ; rapid coagulation of, not due directly to ad- renin, 156-158; rapid co- agulation of, not caused by adrenin in absence of liver and intestines, 157-158, and not caused by increase of blood sugar, 159, 170; coagulation of, hastened by splanchnic stimulation, 162-167, but not in absence of adrenal glands, 167-171 ; possible delay of coagula- tion of, after stimulation INDEX 307 of hepatic nerves, 170 ; co- agulation of, hastened by "painful" stimulation, 172- 177 ; coagulation of, hasten- ed in light anesthesia, 174- 177; rapid coagulation of, after excitement, stopped by severing splanchnic nerves, 180-182; utility of increased sugar in, 188-193 ; distribution of, in pain and excitement, favorable to muscular effort, 201; sugar in, increased by as- phyxia, 209; utility of rapid coagulation of, 211. Bronchioles : dilated by adre- nin, 204. Bulimia : explanation of, 262. Coagulation, see Blood. Coagulometer : graphic, 138- 147. Combat: relation of emotion and endurance in, 225- 226; nature of ancient, 294. Constipation: as result of worry and anxiety, 271. Cortex, cerebral: insensitive- ness of, 242. Cranial autonomic division; functions of, to conserve bodily resources, 30-32, 268 ; activities of, suppress- ed by activities of sym- pathetic division, 268- 272. Curare: action of, antago- nized by adrenin, 132. Dances: relation of excite- ment and endurance in, 222-224. Danger : stimulating effect of, 230. Dervishes : exhibitions of en- durance by, 224. Digestion : interruption of, by strong emotion, 9-12, 13-18, 268-269. Emotions: surface signs of, 3 ; favorable to digestive se- cretions, 4-8 ; unfavorable to digestive secretions, 9- 13; persistence of effects of, on digestive secretions, 12; effects of, on gastric and intestinal contractions, 13-18; in relation to sym- pathetic division, 36 ; in re- lation to adrenal secretion, 44, 52-59, 62-63; increase of blood sugar in, 66, 73; glycosuria in, 70-76; influ- ence of, on distribution of blood in body, 108; faster coagulation of blood in, 177-182, but stopped by cutting splanchnics, 180- 182; value of forced res- piration in, 203; value of bronchiolar dilation in, 204 ; relation to action, 215 ; displayed in a "pattern" response, 218, 282; in re- lation to exhibitions of power and endurance, 215, 229 ; antagonisms between cranial and sympathetic, 268-270, and between sacral and sympathetic, 270- 272; similarity of visceral changes in strong, 275-279 ; dependence of, on cerebral cortex, 282-283. Endurance: feats of, related to great emotion, 217-218; in the excitements of mania and dancing, 222- 224; stimulated by music, 228. Esophagus: contractions of, associated with hunger sen- sation, 259-260. 30$ INDEX Fatigue : of muscle, 84 ; mus- cular, lessened by splanch- nic stimulation, 89-93; as affected by increase of ar- terial pressure, 97-102 ; irritability of muscle in, increased by splanchnic stimulation, 101; explana- tion of effects of varied ar- terial pressure on, 104-106 ; lessens neuro-muscular ir- ritability, 114-117, 120 ; ef- fect of, on curarized mus- cle, 132; utility of adreniii in lessening effects of, 194, 195; of adrenal glands, 199; cessation of hunger contractions in, 262. Fear: anticipatory character of, 186-187 ; associated with action, 188 ; explanation of paralyzing effect of, 189 ; energizing influence of, 216; relation to rage, 275; bodily changes in, like those in rage, 276-277 ; importance of, as a fight- ing emotion, 286. "Fesselungsdiabetes," 69. Fever : absence of hunger in, 242, 263. Fighting emotions : bodily changes in, like those in competitive sports, 219-221, 296; anger and fear as, 285; importance of, 286; satisfactions for, in com- petitive sports, 301. Food: effect of sight and smell of, on gastric secre- tion, 6. Football: glycosuria in play- ers of, 75; relation of ex- citement and power in, 219-221. Frenzy: endurance in, 223, 224. Ganglia: autonomic, 23. Gastric glands: turgescence of, not the cause of hun- ger sensation, 249-250. Gastric juice: psychic secre- tion of, 5-8, 11 ; importance of, for intestinal digestion, 7 ; flow of, inhibited by ex- citement, 9-12, and by pain, 19. Generative organs: innerva- tion of, 32, 33; effects of strong emotions on activ- ities in, 271. Glycosuria: in pain, 69-70; in emotion, 70-76; after football, 75, 221; after ex- aminations, 76 ; depend- ence of, on adrenal glands, 77. Heart : innervation of, 26, 31 ; use of sugar by, 191; stimulated by adrenin, 191, 201. Hunger : compared with appe- tite, 233, 235; description of, 234-236; theories of, 237 ; as a general sensation, 237; disappearance of, as time passes, 238-239 ; when stomach full, 239; may be absent in bodily need, 242- 243; temporarily abolished by indigestible materials, 243; quick onset and peri- odicity of, 244-245; refer- ence of, to stomach region, 245-247 ; not due to empti- ness of stomach, 248; not due to hydrochloric acid in empty stomach, 248; not due to turgid gastric glands, 249-250; as the re- sult of contractions, 251- 253; inhibited by swallow- ing, 254 ; method of record- ing gastric contractions in, INDEX 309 255-256; associated with gastric contractions, 256- 259, and with esophageal contractions, 259 - 260; function of, 263-264, 272- 275. Hydrochloric acid: not the cause of hunger sensation, 248. Intestine : contractions of, inhibited by excitement, 16; innervation of, 27, 31; use of, as test for adrenin in blood, 47-50; contracts when empty, 251-253 ; con- tractions of, may originate hunger sensations, 263. Instincts: relation of, to emo- tions, 187, 188. Irritability: increased in fa- tigued muscle by splanch- nic stimulation, 101 ; neuro- muscular, lessened by fa- tigue, 114-117, 120; when lowered, restored slowly by rest, 119; when lowered, restored quickly by adre- nin, 119-123, 195. "Jumpers" : exhibition of en- durance by, 223. Mania : endurance in, 222. Martial virtues : claims for, by militarists, 287 ; import- ance of preserving, 290- 291; preserved in competi- tive sports, 297-299. Metabolites: influence of, on muscular contraction, 104; action of, opposed by adre- nin, 129 ; increase adrenal secretion, 206-208. Militarists: emphasis of, on strength of fighting in- stincts, 286-288 ; claims of, as to values of war, 287; support for claims of, 287. Muscle: weakness of, after removal of adrenal glands, 81 ; improved contraction of, after injection of adre- nal extract, 82; fatigue of, 84; method of recording fatigue of, 85-86; fatigue of, lessened by splanchnic stimulation, 89-93 ; con- traction of, when fatigued, improved by increased arte- rial pressure, 97-102; irri- tability of, when fatigued, increased by splanchnic stimulation, 101 ; contrac- tion of, when fatigued, less- ened by decreased arte- rial pressure, 102-104; ex- planation of effects of va- ried arterial pressure on fatigued, 104-106; irritabil- ity of, decreased in fatigue, 114-117, 120; decreased ir- ritability of, slowly re- stored by rest, 117-118, and quickly restored by adre- nin, 119-123; contraction of fatigued denervated, in- creased by adrenin, 130; point of action of adrenin in, 128-133; use of , in strug- gle, 189; energy of, from carbonaceous material, 190- 193; disappearance of gly- cogen from, 190; increased efficiency of, with increase of blood sugar, 1^2-193; utility of adrenin in less- ening fatigue of, 194- 195; efficiency of, increased by distribution of blood in pain and excitement, 201. Music: stimulating influence of, 227; influence of mar- tial, 228. Neurones, autonomic: exten- sive distribution of sym- 310 INDEX pathetic, 26; arrangement of sympathetic for diffuse action, 28; restricted dis- tribution of cranial and sa- cral, 29; arrangement for specific action, 30. Olympic games: as physical substitutes for warfare, 297-298. Operations : in light anes- thesia hasten coagulation of blood, 174-177. "Ordeal of rice," 9. Pain : disturbing effect of, on digestion, 18-19; as occa- sion for adrenal secretion, 59-62, 63; glycosuria in, 69-70; influence of, on distribution of blood in body, 108; hastens coagu- lation of blood, 172-177; reflex nature of responses in, 185-187 ; associated with action, 189; stimulat- ing and depressive effects of, 189. Pancreatic juice: flow of, in- hibited by excitement, 13. Philippine Islands: substi- tution of sports for war- fare in, 297. Power : the feeling of, 229. Psychic secretion: of gastric juice, 5-8, 11; of saliva, 6; dependent on cranial auto- nomic innervation, 31. Psychic "tone" : of gastro-in- testinal muscles, 13. Racing: relation of excite- ment and power in, 221. Rage: relation of, to fear, 275; transformation of other emotions into, 276; bodily changes in, like those in fear, 276-277 ; im- portance of, as a fighting emotion, 286. Reflexes : "purposive" char- acter of, 185-186. "Reservoirs of power," 216. Respiration: Utility of in- creased, in pain and ex- citement, 202; value of forced, in lessening dis- tress, 203. Rest: restores irritability lessened by fatigue, 117- 118. Sacral autonomic division : functions of, in mechan- isms for emptying, 32-34; activities of, suppressed by activities of sympathetic division, 270-272. Saliva : psychic secretion of, 6 ; importance of, for taste, 6; flow of, inhibited by ex- citement, 9. Salivary glands: innervation of, by cranial autonomic, 31. "Second wind": explanation of, 210. Sex : instinct of, suppressed by fear and anger, 271. "Sham feeding," 5. Splanchnic nerves: stimula- tion of, causes adrenal se- cretion, 41-43; method of stimulating, 87-88; stimu- lation of, improves contrac- tion of fatigued muscle, 89; stimulation of, hast- ens coagulation of blood, 162-167, but not in absence of adrenal glands, 167-171 ; severance of, stops rapid coagulation following ex- citement, 180-182 ; eating after severance of, 240. Sports: relation of excite- ment and power in, 219- 221, 296; as physical sub- stitutes for warfare, 297- INDEX 311 301; moral values of, 300. Stomach: psychic tonus of, 13; contractions of, inhib- ited by excitement, 14-15, 17, and by pain, 19; in- * nervated by sympathetic neurones, 27, and by cra- nial autonomic, 31; refer- ence of hunger sensation to, 245-247; emptiness of, not the cause of hunger, 248; contractions of, when empty, 251-253; method of recording contractions of, 255-256 ; contractions of, when empty, associated with hunger sensations, 256-259; function of con- tractions of empty, 263- 264. Strength : feats of, related to great emotion, 217-218, 229. Sugar: in blood, 66, 73; in urine, 69-76; relation of adrenal glands to, in blood, 77; increase of, in blood, does not hasten clotting, 159, 170; utility of, when increased in blood, 188- 193; a source of muscular energy, 191-193; a means of increasing muscular effi- ciency, 192-193; use of, in body, not checked by adre- nin, 197-199. Swallowing: inhibits hunger sensation, 254. Sweating: value of, in emo- tion and pain, 203. "Sympathetic" autonomic di- vision: extensive distribu- tion of neurones of, 26; arranged for diffuse ac- tion, 28; antagonistic to cranial and sacral di- visions, 34-36; active in pain and strong emotion. 36; emotions expressed in, opposed to those expressed in cranial and sacral di- visions, 268-272 ; domi- nance of, temporary, 273. Threshold stimulus : as meas- ure of irritability, 111; method of determining, 111-114; increased in fa- tigue, 114-117, 120; when increased, slowly restored by rest, 117-118, and quick- ly restored by adrenin, 119-123. Trial by battle: feats of en- durance in, 226. Vagus nerves: severance of, does not abolish appetite, 240-241, and does not abol- ish hunger contractions of the stomach, 261. Viscera: similar changes in, in various strong emotions, 275-279; changes in, not distinctive for emotions, 280-281. ^ Vomiting: in consequence of pain, 19. Warfare : as an expression of strong emotions, 286 ; phys- ical and moral values claimed for, 287; barbari- ties of, and opposition to, 289-290; moral substitutes for, 292-293; physical sub- stitutes for, 293-297; con- trast between ancient and modern, 294-295. Witnesses : stimulating in- fluence of, 227. Work: effect of, on neuro- muscular irritability, 117; done with use of car- bonaceous material, 190- 193.