Bodily Changes in Pain, Hunger, Fear and Rage

The original of tliis book is in tlie Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. Fear, rage and pain, and the pangs of hunger are all primitive experiences which human beings share with the lower animals. These experiences are properly classed \ as among the most powerful that determine the action of ^ men and beasts. A knowledge of the conditions | which attend these experiences, therefore, is of general and fundamental importance in the interpretation of behavior.

During the past four years there has been conducted,l\ 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-

inate 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- lical 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 imotor 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.

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 — jThg^uick res- toration of fatigued muscle to norrnM 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-

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

The doctrine of Imman development from sub- human antecedents lias done much to unravel the complex nature of man. As a means of interpre- tation this doctrine has been directed chiefly toward the solving of puzzles in the peculiarities of anatomical structure. Thus arrangements in the human body, which are without obvious util- ity, receive rational explanation as being vestiges of parts useful in or characteristic of remote an- cestors— parts retained in man because of age- long racial inheritance. This mode of interpreta- tion has proved applicable also in accounting for functional peculiarities. Expressive actions and( gestures — the facial appearance in anger, for ex-' ample — observed in children and in widely dis- tinct races, are found to be innate, and are best explained as the retention in human beings of responses which are similar in character in lower animals.

From this point of view biology has contributed much to clarify our ideas regarding the motives of human behavior. The social philosophies which 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 tafluence of_certain emotions which express themselves in characteristic instinctive act^.

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 -f^r^ 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^re, how- ever^^other organs, hidden deep— io—the-^body, which do not reveal so obviously as the struc- tures near or in the 's1on^""tEe disturbances of action which attend states of intense feeling. Special methods^'musT he used to deteraiine whether thjesedeep-Jying organs also are included in the complex of an emotional* agitation.

* In the T^g of the term "emotign", the meaning here is not restricted tit violent affective states, but includes "feel-, mgs" 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 shoAvn that not only are the first stages of the digestive process normally started by the pleasur- able taste and smell and sight of food, but also ( that pain and great emotional excitement can seriously interfere with the starting of the pro- cess or its continuation after it has been started. Thus there may be a conflict of feelings and of their bodily accompaniments — a conflict the inter- esting bearing of which we shall consider later.

Emotions Favorable to Normal Secretion of the Digestive Juices The feelings or affective states favorable to the digestive functions have been studied fruit- fully by Pawlow,^ 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 iood. In some of the animals thus operated upon an opening was also made in the esophagus so that when the fQiM^a^s-swaile3sSkd7itdid~not pass to the stom- r ach but propped 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- \ ingj.' 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 relishedi.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

The mere sight or smell of a favorite food may tart the pouring out of gastric juice, as was oted many years ago by Bidder and Schmidt ^ 1 a hungry dog which had a fistulous opening irough the body wall into the stomach. This bservation, reported in 1852, was confirmed later y Schiff and also still later by Pawlow. That le mouth "watej*^" "with a flow of saliva when alatable food is seen or smelled has long been ach common knowledge that the expression, "It lakes my mouth water," is at once recognized as le highest testimony to the attractiveness of an ppetizing dish. That the stomach also "waters" 1 preparation for digesting the food which is to e taken is clearly proved by the above cited ob- Brvations on the dog.

The importance of the initial psychic secretion f saliva for further digestion is indicated when, 1 estimating the function of taste for the pleas- res of appetite, we realize that materials can e tasted only when dissolved in the mouth and lereby brought into relation with the taste or- ans. The saliva which "waters" the mouth as- ures the dissolving of dry but soluble food even ^hen it is taken in large amount. The importance of the initial psychic secretion f gastric juice is made clear by the fact that con-

timiance of the flow of tMs 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 digesjdve. process, therefore, ,i8 conditioned by the satisfactions of the palate,and fhe~cons equent 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,* 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 I

from the fistula a considerable quantity of gastric juice. A number of later observers * 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* found that when the little boy whom he studied chewed agreeable food a more or less active secretion of gastric juice invariably started, whereas the chewing of an indifferent substance, as gutta-percha, was fol- lowed by no secretion. All these observations clearly demonstrate that the normal flow of the first digestive fluids, the saliva and the gastric juice, is favored by the pleasurable feelings which accompany the taste and smell of food dur- ing mastication, or which are roused in anticipa- tion of eating when choice morsels are seen or smelled.

These facts are of fundamental importance in the serving of food, especially when, through ill- ness, the appetite is fickle. The degree of dainti- ness with which nourishment is served, the little attentions to esthetic details — the arrangement of the dishes, the small portions of food, the flower beside the plate — all may help to render food pleasing to the eye and savory to the nos- trils and may be the deciding factors in determin- ing whether the restoration of strength is to be- gin or not.

Emotions Unfavorable to the Normal Secretion of the Digestive Juices The conditions favorable to proper digestion are wholly abolished when unpleasant feelings such as vexation and worry and anxiety, or great emotions such as anger and «f ear, 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.^

What has long been recognized as true of the secretion of saliva has been provedOtrue also of the secretion of gastric juice. ^^ For example, Hornborg 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. Hornborg 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 c^y; 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 i^lso been seen in lower animals under laboratory con- ditions. Le Conte " 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 surroundingsJie 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 "^ 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-j stance the sham feeding lasted five minutes, and the secretion continued for twenty minuteg^, dur-j ing which time 66.7 cubic centimeters of pure gas- tric juice were produced.

On another day a cat was brought into the V^ v V ; ; presence of the dog, whereupon the dog flew into "^^^ , ^s,^i a great fury. The cat was soon removed, and ^^ '\/J'i' 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 ^yK of secretion that the pleasurable excitation which accompanies the taking of food cannot cause th0 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 ^ 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- fiuences unfavorable to digestion, however, are stronger than those which promote it. And evidently, if the digestive process, because of emotionah 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.