Bodily Changes in Pain, Hunger, Fear and Rage

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 :

* This animal had just passed through a period of excite- ment with rapid clotting. 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 niight 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 :

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 : 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 :

The experiments above recorded show that stimulation of the splanchnic nerves results imme- diately, or after a brief period, in a shortening of the coagulation time of the blood — an effect which in different animals varies in duration and intens- ity, and diminishes as the stimulation is repeated. The next question was whether this effect is pro- duced through the adrenal glands. Coagulation Not Hasten^^ed by So.anc_hnic Stimulation if THE Adrenal Glands are Absent

The manner in which splanchnic stimulation pro- duces its effects is indicated in the following ex- periments : 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 — 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 :

The results in this experiment are represented graphically in Fig. 31. 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 process. The splanchnics innervate the intestines and liver even though the adrenal gland is removed. The foregoing experiments indicate that the nerve impulses delivered to these organs do not influence them in any direct manner to accelerate the speed of coagulation. Indeed, in one of the experiments (Dec. 4, see Fig. 31) a high reading about ten min- utes after splanchnic stimulation on the glandless side suggests the possibility of an opposite effect. Direct stimulation of the hepatic nerves on one occasion was followed by a change of the clotting time from 4.5, 5, 4.5, 4.5 minutes during twenty-five minutes before stimulation to 4.5, 7, and 6 minutes during twenty minutes after stimulation.

Since with the adrenals present stimulation of hepatic nerves induces alteration of glycogen in the liver and quick increase of blood sugar,^ 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,^ and in the absence of the liver adre- nin is without influence.* The variations of effect noted after splanchnic stimulation can be accounted for by variations in the adrenin content of the glands. Elliott ^ 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 and operation under light anesthesia were the methods used to affect the afferent nerves. El- liott® 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 :

The results obtained in this ease, 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 : 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 : Nov. 11. — A female cat, very quiet, was placed in the holder at 1.55. The animal was not excited. At 2.10 etherization was begun; the animal was then tracheotomized, and the femoral artery was exposed.

.57 — 1.5 minutes. Anesthesia light; corneal reflex present. 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 : In the foregoing and in other similar instances, a condition of surgical injury, whether just made Figure 33. — Shortening of coagulation time during an operation under hght anes- thesia. At 2 :35 the abdomen was opened, at 2:55 a hgature was passed around the hepatic nerves.

or being made, was accompanied by more rapid clotting of blood when the degree of anesthesia was lessened. This condition was one which, if allowed to go further in the same direction, would result in pain. Both direct electrical stimulation and also surgical operation of a nature to give pain in the unanesthetized animal result, therefore, in faster clotting. It is worthy of note that after deeerebration clot- ting apparently occurred no faster because the ab- domen had been opened, although in the decere- 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 process. The animals used on November 11 and 13 (see pp. 175, 176) are examples of calm acceptance of being placed on the holder ; and furthermore, these animals were anesthetized without much dis- turbance. As the figures indicate, the clotting from the first occurred at about the average rate.

In sharp contrast to these figures are those ob- tained when a vigorous animal is angered : Oct. 30. — A very vigorous eat 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 : 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 '' 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 : 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 : Nov. 5. — A cat was etherized at 2.35. At 2.39 artificial respiration by tracheal cannula was be- guQ, the air passing through an ether bottle. The clotting occurred thus:

Nov. 7. — A cat was etherized at 1.55 under ex- citement and with tail hairs erect. At 2.13 the ani- Figure 34. — About two-thirds original size. Record of rapid clotting (less than a half-minute) after emotional excitement. At 11:07 the left, at 11:12 the right splanchnic nerves were out; the clotting then required 3:5 minutes. The marks below the time record indicate the moments when the samples were drawn. 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.

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^slioaLJiiat such stimulation as in the unanesthetized^animal would cause pain, and also such emotions as Jear and rage, are capable of greatly shoxtejiing^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. 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 adrenin?

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^jt 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 terrifyiag aspect produced by the bristling of the hair and the uncovering of the teeth in# an access of rage.^ Tne 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 existe^^ Earlier writers on organic evolution pointed out the antici- patory character of these responses. According to Spencer,^ "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 ^ 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 fightiag or attack. Crile * 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?