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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 

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- 




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. 


Boston, Mass. 





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 



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 






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 



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 



Glycosuria from pain Emotional glycosuria The role 
of the adrenal glands in emotional glycosuria . 66-80 



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 





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 



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 



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 



Coagulation hastened by splanchnic stimulation Co- 
agulation not hastened by splanchnic stimulation if 



the adrenal glands are absent Coagulation hast- 
ened by "painful" stimulation Coagulation hastened 

in emotional excitement 161-183 




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 



"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 


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- 


. . 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 


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 



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 


INDEX 305 




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 



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 


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. 


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. 


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 


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 


was justified that this was a true psychic 

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- 


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 


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 

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. 



\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 


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 


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 


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. 


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. 


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 


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 


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 


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 


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- 


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 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- 


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 


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. 


1 Pawlow : The Work of the Digestive Glands, London, 

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. 

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. 


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. 

19 Pawlow : Loc. cit., p. 56. 

20 Mantegazza : Fisiologia del Dolore, Florence, 1880, p. 



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 skeletal muscles receive their nerve supply 
direct from the central nervous system, i. e., the 



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 

Tear gland 
Dilator of pupil 

Artery of salivary gland 


Surface artery 
Sweat gland 



Surface artery 

Sweat gland 



tf Visceral artery 


Adrenal gland 


Surface artery 

Sweat gland 




Artery of external 

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. 


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 


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- 


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 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- 


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 


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 


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 


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 


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 


The cranial autonomic, represented by the 

vagus nerves, is the part of the visceral nervous 


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- 


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. 


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- 

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 


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- 


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. 


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- 


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. 


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. 


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. 


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. 


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 


1 Cannon : The American Journal of Psychology, 1914, 
xxv, p. 257. 


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. 



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 



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- 


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 


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 


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 

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. 



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 


a few cases longer. Samples of blood were taken 
within a few minutes before and after the period. 



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 


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 

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- 


quently treated in the same manner, were now 
tested for their content of 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 


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- 



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 


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. 


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. 


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. 



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. 


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 



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. 


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 


the cat had been barked at for about fifteen min- 

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 

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" 


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 


secreted by them would produce precisely the 
inhibition of contraction which was in fact pro- 

(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- 


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- 

(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 


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. 


As mentioned in the first chapter, stimulation of 
sensory fibres in one of the larger nerve trunks 


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- 

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- 


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. 


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. 


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 


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 


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 


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. 


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. 



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 



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 


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. 



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- 

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- 


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. 


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- 


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 

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 

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 


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 

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, 


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- 


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, 


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. 


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- 

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 


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- 


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 


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- 

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- 


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 


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. 


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- 

23 Wertheimer and Battez : Archives Internationales cle 
Physiologic, 1910, ix, p. 392. 





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- 



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 

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. 


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- 

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 


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 

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. 


Care was taken to maintain the body temperature 
at its normal level throughout each experiment. 


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 

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 


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 



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 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- 

In applying the electrodes the left splanchnic 
nerves were first freed from their surroundings 
and tightly ligatured as close as possible to their 


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- 

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 


many different ways which' have already been de- 
scribed (see p. 41). 


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. 


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 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- 


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. 


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. 


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 


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- 


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 



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. 

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. 





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- 



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. 


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 


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. 



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- 


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 


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 


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 


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. 


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 


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 


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 


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 


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 


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. 


As stated in a previous paragraph, there is evi- 
dence that the vessels supplying a muscle dilate 


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 


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- 


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. 


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. 



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. 


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 



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 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 


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. 


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- 


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- 

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 


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 

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 


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 


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. 


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 


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. 



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. 


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 

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. 


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- 

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- 

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 



taken ; that of the nerve-muscle dropped to normal 
0.59 units a recovery of 100 per cent, and that 



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- 

(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- 

of the muscle remained unaltered 26 per cent 
above its normal threshold. 
In Fig. 20 the threshold (at 5) was taken five 


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- 


ence of adrenin in promptly lowering the high, 
fatigue threshold of neuro-muscular irritability. 



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 


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 


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 



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. 


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. 


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. 


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 


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 

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 


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- 

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- 


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. 


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. 


1 Qruber: American Journal of Physiology, 1913, xxxii, 
p. 437. 

2 E. L. Porter : ' American Journal of Physiology, 1912, 
xxxi, p. 149. 


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. 



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 



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 


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 



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. 


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 


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. 


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- 

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- 

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 


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 


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- 


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 




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 


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 


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- 


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 


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- 

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. 


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). 


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. 


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- 


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 " 

In these instances the animals were decere- 
brated. For decerebrate cats, the least amount of 



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 

.531.5 " 
;.65 1.5 
.582 " 

3.002.5 minutes 

.031.5 " 

051.5 " 
.072.5 " 

193 " 
.233 " 


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- 



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, 


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 


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 


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 

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. 


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 


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- 


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 


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 


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. 


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. 



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- 



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. 


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 " 



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 : 


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. 




and for twenty-five minutes thereafter it was four 

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 


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. 


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 


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 

5.02 to .04 Stimulation of right splanchnic. 

.06 4 minutes 


.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 


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 


the other side (still connected with the adrenal 
gland) produces a sharp hastening of the clotting 

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), 


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 



made in order to obtain an answer to that ques- 


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 




;50 6:00 

30 :30 


FIGURE 32. Three shortenings of coagulation time after stimu- 
lation of the left sciatic nerve, at 4:23-:25, at 4:45-:50 (stronger), 

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 


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 


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 " 


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 


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 

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 : 



2.08 6 minutes 

Anesthesia light. 
Etherization begun again. 


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 


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. 


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 


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 

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 


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- 


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 " 


.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. 

Nov. 5. A cat was etherized at 2.35. At 2.39 
artificial respiration by tracheal cannula was be- 


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 " 


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. 

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- 


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. 


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. 



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 



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 




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 


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 


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! 


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. 


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 


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." 


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 


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 


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- 


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 

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 


benefit to the organism in the strenuous muscular 
efforts involved in flight or conflict or struggle to 
be free. 


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 


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 

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 


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 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.) 


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 


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 


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 

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 


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 


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- 


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 


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 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- 


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. 


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 


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 


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 


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 


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 


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 


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. 


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. 


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. 



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 


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. 


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. 


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. 


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, 



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 



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. 


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." 


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- 


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 

* 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. 


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. 


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- 


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 


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 


dramatic development of an acme of excitement 
as the moment approaches when the last desperate 
effort to win is put forth. 


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 


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- 


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 


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- 


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 


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 


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. 


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 


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- 


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. 


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 


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. 



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- 


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. 


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 



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. 


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 


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 


quantity rather than quality, and he wants it at 

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. 


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 


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 

Two main theories have been advocated. The 


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 


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 


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. 


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 


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 


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. 



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. 


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 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 

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. 





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 

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 


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 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 


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 


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- 

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 

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 


would sustain the theory that hunger has a local 
outlying source. 


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. 


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 


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. 


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.) 


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 


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. 


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 argument commonly used against the gas- 
trio contraction theory is that the stomach is not 


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.- 


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 


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 


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 


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. 


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 


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- 


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 

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 


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 


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 


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. 


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 


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 

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- 


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. 


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. 


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. 


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. 


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. 


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? 





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- 


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. 


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. 


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- 


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 

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 


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 


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 


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 

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 


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). 


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 




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- 


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 

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 


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). 


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- 


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 


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- 

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- 


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. 


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, 


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. 



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. 



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. 


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 



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 


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- 


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.* 


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. 


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. 


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. 


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 


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. 



"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 


temper as past history has inflamed the military 

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- 


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 


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- 


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 


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.) 


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. 


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 


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* 


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 

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 


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- 


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. 


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. 


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. 



10. The Effect of Adrenal Secretion on Muscular Fatigue. 
By W. B. Cannon and L. B. Nice. Ibid., 1913, xxxii, pp. 

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. 

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. ?. 


Adrenal extract: effect of, 
on muscular contraction, 

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- 

Amyl nitrite: effect of, on 
contraction of fatigued 
muscle, 126. 




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- 

Behavior : biological explana- 
tion of, 2. 

Bile: flow of, inhibited by 
excitement, 13. 

Bladder: innervation of, 27, 
32; effects of emotions on, 

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 



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, 

Coagulation, see Blood. 

Coagulometer : graphic, 138- 

Combat: relation of emotion 
and endurance in, 225- 
226; nature of ancient, 

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- 

Curare: action of, antago- 
nized by adrenin, 132. 

Dances: relation of excite- 
ment and endurance in, 

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, 

Esophagus: contractions of, 
associated with hunger sen- 
sation, 259-260. 



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, 

Frenzy: endurance in, 223, 

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, 

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, 



255-256; associated with 
gastric contractions, 256- 
259, and with esophageal 
contractions, 259 - 260; 
function of, 263-264, 272- 

Hydrochloric acid: not the 
cause of hunger sensation, 

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- 



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, 

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- 

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, 

"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- 



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- 

Strength : feats of, related to 
great emotion, 217-218, 

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, 

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- 


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