Transcriber's Note
The List of Illustrations following the "Contents" section has been
added by the transcriber; the wording of captions in that List has
in some cases been condensed from the captions in the body of the
book.
Italic font is indicated by _underscores_.
BODILY CHANGES
IN PAIN, HUNGER,
FEAR AND RAGE
BODILY CHANGES
IN PAIN, HUNGER,
FEAR AND RAGE
AN ACCOUNT OF RECENT RESEARCHES
INTO THE FUNCTION
OF EMOTIONAL EXCITEMENT
BY
WALTER B. CANNON
GEORGE HIGGINSON PROFESSOR OF PHYSIOLOGY IN
HARVARD UNIVERSITY
[Illustration]
NEW YORK AND LONDON
D. APPLETON AND COMPANY
1915
Copyright, 1915, by
D. APPLETON AND COMPANY
Printed in the United States of America
TO MY COLLABORATORS IN THESE RESEARCHES
DANIEL DE LA PAZ
ALFRED T. SHOHL
WADE S. WRIGHT
ARTHUR L. WASHBURN
HENRY LYMAN
LEONARD B. NICE
CHARLES M. GRUBER
HOWARD OSGOOD
HORACE GRAY
WALTER L. MENDENHALL
WITH PLEASANT MEMORIES OF OUR
WORK TOGETHER
PREFACE
Fear, rage and pain, and the pangs of hunger are all primitive
experiences which human beings share with the lower animals.
These experiences are properly classed as among the most powerful
that determine the action of men and beasts. A knowledge of the
conditions which attend these experiences, therefore, is of general
and fundamental importance in the interpretation of behavior.
During the past four years there has been conducted, in the Harvard
Physiological Laboratory, a series of investigations 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 convenient
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
eliminate 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 medical sciences.
My first interest in the conditions attending pain, hunger and strong
emotional states was stimulated during the course of a previous
series of researches on the motor activities of the alimentary
canal. A summary of these researches appeared in 1911, under the
title, “The Mechanical Factors of Digestion.” The studies recorded
in the present volume may be regarded as a natural sequence of
observations on the influence of emotional states on the digestive
process, which were reported in that volume.
W. B. Cannon.
CONTENTS
CHAPTER I
PAGES
THE EFFECT OF THE EMOTIONS ON DIGESTION
Emotions favorable to normal secretion of the digestive
juices--Emotions unfavorable to normal secretion of
the digestive juices--Emotions favorable and unfavorable
to contractions of the stomach and intestines--The
disturbing effect of pain on digestion 1-21
CHAPTER II
THE GENERAL ORGANIZATION OF THE VISCERAL
NERVES CONCERNED IN EMOTIONS
The outlying neurones--The three divisions of the outlying
neurones--The extensive distribution of neurones
of the “sympathetic” or thoracico-lumbar division
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 sympathetic
division antagonistic to both the cranial and
the sacral--Neurones of the sympathetic division and
adrenal secretion have the same action 22-39
CHAPTER III
METHODS OF DEMONSTRATING ADRENAL SECRETION
AND ITS NERVOUS CONTROL
The evidence that splanchnic stimulation induces adrenal
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
CHAPTER IV
ADRENAL SECRETION IN STRONG EMOTIONS
AND PAIN
The evidence that adrenal secretion is increased in emotional
excitement--The evidence that adrenal secretion
is increased by “painful” stimulation--Confirmation
of our results by other observers 52-65
CHAPTER V
THE INCREASE OF BLOOD SUGAR IN PAIN AND
GREAT EMOTION
Glycosuria from pain--Emotional glycosuria--The rôle
of the adrenal glands in emotional glycosuria 66-80
CHAPTER VI
IMPROVED CONTRACTION OF FATIGUED MUSCLE
AFTER SPLANCHNIC STIMULATION OF THE
ADRENAL GLAND
The nerve-muscle preparation--The splanchnic preparation--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 adrenal
secretion 81-94
CHAPTER VII
THE EFFECTS ON CONTRACTION OF FATIGUED
MUSCLE OF VARYING THE ARTERIAL
BLOOD PRESSURE
The effect of increasing arterial pressure--The effect of
decreasing arterial pressure--An explanation of the
effects of varying the arterial pressure--The value
of increased arterial pressure in pain and strong
emotion 95-109
CHAPTER VIII
THE SPECIFIC RÔLE OF ADRENIN IN COUNTERACTING
THE EFFECTS OF FATIGUE
Variations of the threshold stimulus as a measure of
irritability--The method of determining the threshold
stimulus--The lessening of neuro-muscular irritability
by fatigue--The slow restoration of fatigued
muscle to normal irritability by rest--The quick restoration
of fatigued muscle to normal irritability
by adrenin--The evidence that the restorative action
of adrenin is specific--The point of action of
adrenin in muscle 110-134
CHAPTER IX
THE HASTENING OF THE COAGULATION OF BLOOD
BY ADRENIN
The graphic method of measuring the coagulation time--The
effects of subcutaneous injections of adrenin--The
effects of intravenous injections--The hastening
of coagulation by adrenin not a direct effect on the
blood 135-160
CHAPTER X
THE HASTENING OF COAGULATION OF BLOOD IN
PAIN AND GREAT EMOTION
Coagulation hastened by splanchnic stimulation--Coagulation
not hastened by splanchnic stimulation if
the adrenal glands are absent--Coagulation hastened
by “painful” stimulation--Coagulation hastened
in emotional excitement 161-183
CHAPTER XI
THE UTILITY OF THE BODILY CHANGES IN PAIN
AND GREAT EMOTION
The reflex nature of bodily responses in pain and the
major emotions, and the useful character of reflexes--The
utility of the increased blood sugar as
a source of muscular energy--The utility of increased
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
CHAPTER XII
THE ENERGIZING INFLUENCE OF EMOTIONAL EXCITEMENT
“Reservoirs of power”--The excitements and energies of
competitive sports--Frenzy and endurance in ceremonial
and other dances--The fierce emotions and
struggles of battle--The stimulating influence of
witnesses and of music--The feeling of power 215-231
CHAPTER XIII
THE NATURE OF HUNGER
Appetite and hunger--The sensation of hunger--The
theory that hunger is a general sensation--Weakness
of the assumptions underlying the theory that
hunger is a general sensation--Body need may exist
without hunger--The theory that hunger is of general
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 reference--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 gastric
mucous membrane--Hunger the result of contractions--The
“empty” stomach and intestines contract--Observations
suggesting that contractions
cause hunger--The concomitance of contractions and
hunger in man 232-266
CHAPTER XIV
THE INTERRELATIONS OF EMOTIONS
Antagonism between emotions expressed in the sympathetic
and in the cranial divisions of the autonomic
system--Antagonism between emotions expressed
in the sympathetic and in the sacral divisions
of the autonomic system--The function of
hunger--The similarity of visceral effects in different
strong emotions and suggestions as to its psychological
significance 267-284
CHAPTER XV
ALTERNATIVE SATISFACTIONS FOR THE FIGHTING
EMOTIONS
Support for the militarist estimate of the strength of
the fighting emotions and instincts--Growing opposition
to the fighting emotions and instincts as
displayed in war--The desirability of preserving the
martial virtues--Moral substitutes for warfare--Physical
substitutes for warfare--The significance of international
athletic competitions 285-301
A LIST OF PUBLISHED RESEARCHES FROM THE
PHYSIOLOGICAL LABORATORY IN HARVARD
UNIVERSITY 302-303
INDEX 305
LIST OF ILLUSTRATIONS
Figure Page
1. Diagram of the more important distributions of the
autonomic nervous system 25
2. Diagram of the arrangements for recording contractions of
the intestinal muscle 49
3. Intestinal muscle beating in inactive blood 53
4. Alternate application of “excited” blood and “quiet”
blood, from the same animal, to intestinal muscle initially
beating in Ringer’s solution 55
5. The effect of prolonging the excitement 55
6. Failure of the cava blood to produce inhibition when
excitement has occurred after removal of the adrenal glands 57
7. Effect of adding adrenin to formerly inactive blood 58
8. The effect of bubbling oxygen through active blood 59
9. Intestinal muscle beating in normal vena cava blood 62
10. The shielded electrodes used in stimulating the splanchnic
nerves 87
11. Contraction of the _tibialis anticus_ and stimulation
of the left splanchnic nerves 89
12. Arterial blood pressure with membrane manometer,
contractions of _tibialis anticus_, and splanchnic
stimulation 91
13-17. Effect of varying arterial blood pressure upon muscular
contraction over time 98-104
18. Threshold stimulus of muscles during an experiment 116
19. Threshold stimulus of muscles during an experiment 122
20. Threshold stimulus of muscles during an experiment 124
21. Effect of adrenin injection upon blood pressure and
contractions of the _tibialis anticus_ muscle 128
22. Effect of amyl nitrite injection upon blood pressure and
contractions of the _tibialis anticus_ muscle 128
23. Effect of adrenin injection upon blood pressure and
contractions of the _tibialis anticus_ muscle
when denervated 131
24. Diagram of the graphic coagulometer 139
25. Record of five successive tests of coagulation 145
26. Shortening of coagulation time after injection of adrenin 151
27. Differing effects upon the coagulation time of slow and
rapid injections of adrenin 153
28. Persistent shortening of the coagulation time after
injection of adrenin when brain and upper cord pithed 154
29. Shortening of coagulation time after stimulation of
the left splanchnic nerves 163
30. Shortening of coagulation time after stimulation of
the left splanchnic nerves 164
31. Results of stimulating the left splanchnic nerves after
removal of the left adrenal gland; and of stimulating
the right splanchnic nerves with right adrenal gland
present 169
32. Three shortenings of coagulation time after stimulation
of the left sciatic nerve 174
33. Shortening of coagulation time during an operation
under light anesthesia 175
34. Record of rapid clotting after emotional excitement 180
35. Rapid clotting after emotional excitement, with slowing
of the process when the splanchnic nerves were cut in the
thorax 182
36. Adrenal secretion produced by asphyxia 208
37. Intragastric pressure, respiration and report of
hunger pangs against time 257
38. The same conditions as in Fig. 37 259
39. Compression of thin rubber bag in the lower esophagus,
and report of hunger pangs against time 260
BODILY CHANGES IN PAIN, HUNGER, FEAR AND RAGE
CHAPTER I
THE EFFECT OF THE EMOTIONS ON DIGESTION
The doctrine of human development from subhuman antecedents has
done much to unravel the complex nature of man. As a means of
interpretation 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 utility,
receive rational explanation as being vestiges of parts useful in or
characteristic of remote ancestors--parts retained in man because
of age-long racial inheritance. This mode of interpretation has
proved applicable also in accounting for functional peculiarities.
Expressive actions and gestures--the facial appearance in anger,
for example--observed in children and in widely distinct 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 calculated 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 psychologists. More and more it is appearing that in
men of all races and in most of the higher animals, the springs of
action are to be found in the influence of certain emotions which
express themselves in characteristic instinctive acts.
The rôle which these fundamental responses in the higher organisms
play in the bodily economy has received little attention. As a realm
for investigation the bodily changes in emotional excitement have
been left by the physiologists to the philosophers and psychologists
and to the students of natural history. These students, however,
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 meager.
There are, of course, many surface manifestations 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
respiration, 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 disturbances 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, however, other organs, hidden deep in
the body, which do not reveal so obviously as the structures 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.
*[Footnote: In the use of the term “emotion” the meaning here is
not restricted to violent affective states, but includes “feelings”
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 important degree by
feelings are those concerned with digestion. And the relations of
feelings to the activities of the alimentary canal are of particular
interest, because recent investigations have shown that not only
are the first stages of the digestive process normally started by
the pleasurable taste and smell and sight of food, but also that
pain and great emotional excitement can seriously interfere with
the starting of the process or its continuation after it has been
started. Thus there may be a conflict of feelings and of their
bodily accompaniments--a conflict the interesting 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 fruitfully by Pawlow,[1] of Petrograd, through
ingenious experiments on dogs. By the use of careful 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 arrangement 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 stomach but dropped
out on the way. All the pleasures of eating were thus experienced,
and there was no necessity of stopping because of a sense of fulness.
This process was called “sham feeding.” The well-being of these
animals was carefully attended to, they lived the normal life of
dogs, and in the course of months and years became 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 persisted as long as the dog
chewed and swallowed the food, and continued for some time after
eating 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 presented to
them was agreeable, the conclusion was justified that this was a
true psychic secretion.
The mere sight or smell of a favorite food may start the pouring
out of gastric juice, as was noted many years ago by Bidder and
Schmidt[2] in a hungry dog which had a fistulous opening through the
body wall into the stomach. This observation, reported in 1852, was
confirmed later by Schiff and also still later by Pawlow. That the
mouth “waters” with a flow of saliva when palatable food is seen or
smelled has long been such common knowledge that the expression,
“It makes my mouth water,” is at once recognized as the highest
testimony to the attractiveness of an appetizing dish. That the
stomach also “waters” in preparation for digesting the food which
is to be taken is clearly proved by the above cited observations
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 pleasures of appetite, we realize that materials
can be tasted only when dissolved in the mouth and thereby brought
into relation with the taste organs. The saliva which “waters” the
mouth assures 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 continuance of the flow of this
juice during digestion 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 secretion of the pancreatic juice and bile are
called forth by the action of this same acid on the mucous 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 esophagus
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, Richet,[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 children, 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
followed 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 during mastication, or which
are roused in anticipation of eating when choice morsels are seen
or smelled.
These facts are of fundamental importance in the serving of food,
especially when, through illness, the appetite is fickle. The
degree of daintiness 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 nostrils and
may be the deciding factors in determining whether the restoration
of strength is to begin 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 fear, are allowed to prevail.
This fact, so far as the salivary secretion 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 practical utilization of the knowledge
that excitement is capable of inhibiting the salivary flow. When
several persons were suspected of crime, the consecrated 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, Hornborg was unable to confirm in his little patient 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 contrary, became vexed when he could not eat at
once, and began to cry; then no secretion appeared. Bogen also has
reported the instance of a child with closed esophagus and gastric
fistula, who sometimes fell into such a passion in consequence 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 conditions. Le Conte[6] declares that in
studying gastric secretion it is necessary to avoid all circumstances
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 experimental procedure, it no
longer had an inhibitory effect. The studies of Bickel and Sasaki[7]
confirm 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 feeding
was attended by a copious flow of gastric juice, a true psychic
secretion, resulting from the pleasurable taste of the food. In
a typical instance the sham feeding lasted five minutes, and the
secretion continued for twenty minutes, during which time 66.7
cubic centimeters of pure gastric 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 mention. During a
period of twenty minutes, corresponding 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 emotions 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 certain height, the dog was infuriated for five minutes
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 pleasurable 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 secretion long outlasted the period of eating, although no
food entered the stomach. The influences 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
digestion 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 excitement. Recently Oechsler[9] has reported
that in such psychic disturbances as were shown by Bickel and Sasaki
to be accompanied by suppressed secretion of the gastric juice,
the secretion of pancreatic juice may be stopped, and the flow of
bile definitely checked. All the means of bringing about chemical
changes in the food may be thus temporarily abolished.
Emotions Favorable and Unfavorable to the Contractions
of the Stomach and Intestines
The secretions of the digestive glands and the chemical changes
wrought by them are of little worth unless the food is carried
onward through the alimentary canal into fresh regions of digestion
and is thoroughly exposed to the intestinal wall for absorption.
In studying these mechanical aspects of digestion I was led to
infer[10] that just as there is a psychic secretion, so likewise
there is probably a “psychic tone” or “psychic 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 Röntgen 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
stomach; and, indeed, the movements of almost the entire alimentary
canal are wholly stopped during great excitement. In my earliest
observations 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 Röntgen
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 contentment
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 breathing 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 Le 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 Röntgen rays, and during that time not
the slightest beginning of peristaltic activity appeared; yet the
only visible indication of excitement 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 disturbances are attended by abolition of peristalsis.
The observations on the rabbit have been confirmed 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
observations on the dog also have been confirmed; Lommel[15] found
that small dogs in strange surroundings might have no contractions
of the stomach for two or three hours. And whenever the animals
showed any indications of being uncomfortable 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 (segmentation) in the small intestine, and the
reversed 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 animals, 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 Müller[16] 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 distress, 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, mentioned 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 instance. 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 appeared at the consultant’s office an hour after having
eaten a test meal. An examination of the gastric contents revealed
no free acid, no digestion of the test breakfast, and the presence
of a considerable amount of the supper of the previous evening.
The explanation of this stagnation 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 becoming uncontrollably drunk, and
that he had by his escapades given his wife a night of turbulent
anxiety. The second morning, after the woman had had a good rest,
the gastric contents were again examined; the proper acidity
was found, and the test breakfast had been normally digested and
discharged.
These cases are merely illustrative and doubtless can be many times
duplicated in the experience of any physician concerned largely with
digestive 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 characteristic 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 disturbances, “emotional”
dyspepsia is better than “nervous” dyspepsia.[17]
The Disturbing Effect of Pain on Digestion
The advocates of the theory of organic evolution early pointed out
the similarity between the bodily disturbances in pain and in the
major emotions. The alterations of function of internal organs 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. Wertheimer[18] proved many years since
that stimulation of a sensory nerve in an anesthetized animal--such
stimulation as in a conscious animal would induce pain--quickly
abolished the contractions of the stomach. And Netschaiev, working
in Pawlow’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 beings. Mantegazza,[20] in his account of
the physiology of pain, has cited a number of such examples, 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 vomiting and diarrhea. The
expression, “sickening pain” is testimony to the power of strong
sensory stimulation to upset the digestive processes profoundly.
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 importance in understanding not only the operation
of conditions favorable or unfavorable to digestion but also in
obtaining insight into the conflicts of emotional states. Since a
consideration of the arrangement and mode of action of these nerves
will establish a firm basis for later analysis and conclusions,
they will next be considered.
REFERENCES
[Footnote 1: Pawlow: The Work of the Digestive Glands, London,
1902.]
[Footnote 2: Bidder and Schmidt: Die Verdauungssäfte und der
Stoffwechsel, Leipzig, 1852, p. 35.]
[Footnote 3: Richet: Journal de l’Anatomie et de la Physiologie,
1878, xiv, p. 170.]
[Footnote 4: See Hornborg: Skandinavisches Archiv für Physiologie,
1904, xv, p. 248. Cade and Latarjet: Journal de Physiologie et
Pathologie Générale, 1905, vii, p. 221. Bogen: Archiv für die
gesammte Physiologie, 1907, cxvii, p. 156. Lavenson: Archives of
Internal Medicine, 1909, iv, p. 271.]
[Footnote 5: Lea: Superstition and Force, Philadelphia, 1892, p.
344.]
[Footnote 6: Le Conte: La Cellule, 1900, xvii, p. 291.]
[Footnote 7: Bickel and Sasaki: Deutsche medizinische Wochenschrift,
1905, xxxi, p. 1829.]
[Footnote 8: Bickel: Berliner klinische Wochenschrift, 1906, xliii,
p. 845.]
[Footnote 9: Oechsler: Internationelle Beiträge zur Pathologie und
Therapie der Ernährungstörungen, 1914, v, p. 1.]
[Footnote 10: Cannon: The Mechanical Factors of Digestion, London
and New York, 1911, p. 200.]
[Footnote 11: Cannon and Washburn: American Journal of Physiology,
1912, xxix, p. 441.]
[Footnote 12: Cannon: The American Journal of Physiology, 1898, i,
p. 38.]
[Footnote 13: Cannon: American Journal of Physiology, 1902, vii,
p. xxii.]
[Footnote 14: Auer: American Journal of Physiology, 1907, xviii,
p. 356.]
[Footnote 15: Lommel: Münchener medizinische Wochenschrift, 1903,
i, p. 1634.]
[Footnote 16: Müller: Deutsches Archiv für klinische Medicin, 1907,
lxxxix, p. 434.]
[Footnote 17: Rosenbach: Berliner klinische Wochenschrift, 1897,
xxxiv, p. 71.]
[Footnote 18: Wertheimer: Archives de Physiologie, 1892, xxiv, p.
379.]
[Footnote 19: Pawlow: _Loc. cit._, p. 56.]
[Footnote 20: Mantegazza: Fisiologia del Dolore, Florence, 1880,
p. 123.]