Q P 141 U.C. B RAIT BIOL B 3 37^ 173 APM-li-iV AN EXPERIMENTAL STUDY OF HUNGER IN ITS RELATION TO ACTIVITY By TOMI WADA, A.M. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, in the Faculty of Philosophy, Columbia University REPRINTED FROM ARCHIVES OF PSYCHOLOGY R. S. WOODWORTH, EDITOR No. 57 NEW YORK JUNE, 1922 AN EXPERIMENTAL STUDY OF HUNGER IN ITS RELATION TO ACTIVITY By TOMI WADA, A.M. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, in the Faculty of Philosophy, Columbia University REPRINTED FROM ARCHIVES OF PSYCHOLOGY R. S. WOODWORTH, EDITOR No. 57 NEW YORK JUNE, 1922 a- 3 CONTENTS. Chapter Page I. Introduction and General Description of the Present Study. . 5 1. Introduction . . .- '. .. . . .5 2. Main Purposes ... . . . . 7 3. The Apparatus . . . ,. . . . . 8 4. The Subjects . . . .. . . . .10 5. The Main Experiments . . . . . .11 II. Nature of Hunger . ' . . . . . .12 1. Hunger Mechanism . . . . . .12 2. Activities of the Stomach . ... . . .13 III. Correlation of the Hunger Rhythm with Other Physiological Conditions . . . . ... . .23 1. Respiration . . . . ... , . .23 2. Vasomotor Volume . . . w . . . .23 3. Salivary Secretion . ,- . > . . . " . - . . 23 IV. Correlation of the Hunger Rhythm with the Sensation of Hunger 24 V. Correlation of the Hunger Rhythm with Bodily Activities . 27 1. Bodily Movements of Men During Sleep . . .27 2. Correlation of the Hunger Rhythm with Bodily Movements of Men During Sleep . . . . . 27 3. Correlation of the Hunger Rhythm with Bodily Movements of Men During Waking State . . . . .30 4. Bodily Movements of Infants . . . .31 5. Bodily Movements of Albino Rats . . . .32 VI. Correlation of the Hunger Rhythm with Dreaming . 33 VII. Correlation of the Hunger Rhythm with Motor Activity . . 35 VIII. Correlation of the Hunger Rhythm with Mental Activity . . 45 IX. The Effects of Various Stimuli upon the Hunger Rhythm . 54 1. The Effect of Mechanical Stimulation . .- . .54 2. The Effect of Drugs . . . " . - . .56 3. The Effect of Conscious Effort, Thought, Sight, Smell and Taste of Food . . . .' . . .58 4. The Effect of Nausea from Rotation . . . .59 5. The Effect of Electric Shocks . ... :, .- . 60 6. The Effect of Prolonged Work . . . . .60 7. The Effect of Reading Exciting Stories . . ... .61 X. Conclusions ... 62 5078"i PREFACE The present study of hunger and activity was undertaken at the psychological laboratory of Johns Hopkins Hospital, first in the summer of 1920, and more systematically, from February, 1921, to February, 1922. Owing to the fact that it is a new field of work for the psychological laboratory, and especially, that it was a new field for the experimenter, numerous trials and errors were made. Though further researches are eagerly h'oped for and needed along this line, it is encouraging that this one and a half year's experimentation yielded certain definite results, which are presented in the following pages. ACKNOWLEDGMENTS Acknowledgments are due to Professor Edward L. Thorn- dike for guidance given to the writer in the study of general psychology as preparation for the present experiment, and for his introduction of the writer to the psychological laboratory of Johns Hopkins Hospital. The author's gratitude is sin- cerely expressed to Dr. Arthur I. Gates, whose encouragement and advice were immeasurable. Special acknowledgment is due to Dr. Curt P. Richter of Johns Hopkins Hospital for his valuable suggestions and assistance. To the parents of the two babies the author feels great gratitude and admiration for their sacrificial interest in the scientific work and the privileges given to the writer. To Professor R. S. Woodworth for the present publication, and to Miss Caroline Stackpole, Miss Marian Bene- dict, and Miss Mary Evenden, who corrected the English, and to other people who assisted the present work by becoming sub- jects or by reading manuscript and proof, acknowledgment is gratefully made. TOMI WADA. June, 1922. CHAPTER I. 1. INTRODUCTION. The need to understand the fundamental drives of human be- havior is tremendously increasing in these years of social unrest, economic readjustment, and educational reformation. Pointing out the lack of understanding as to the fundamental urges of labor problems, the late Mr. Carleton Parker 1 says that the laborers' philosophy is a stomach philosophy, and their political in- dustrial revolt is a hunger riot. Indeed, hunger is one of the strongest of human urges. "On the same plane with pain and the dominant emo- tions of fear and rage as agencies which determine the action of the organism, is the sensation of hunger," says Cannon 2 . "It is a sensation so peremptory, so disagreeable, so tormenting, that men have committed crimes in order to assuage it. It has led to cannibalism, even among the civilized. It has resulted in suicide. That dull ache, or gnawing pain, referred to the lower midchest region and the epigastrium, may take imperious control of human actions." 2 Plunger not only compels the striped muscles to seek food, but urges man and animals to fight, and even to risk life itself. Hunger is such a strong drive that the term itself stands as a representative of all wishes and desires. 'When the effort to satisfy hunger is thwarted, the whole organism reacts to the situation, or the thwarting agent, with such hyper-tension of all organs and muscles and fibres that the excitement may lead to various types of defensive behavior. Moreover, as McDougall 3 says that all instinctive impulses may, with opposition or obstruction, give place to, or are complicated by, the pugnacious, or combative, impulse directed against the source of the obstruction. Thus hunger may become a dynamic force of destructive or constructive emotions and behaviors. In the primitive type of man, hunger plays such a role that the greater part of his daily activity is directed by it. Food was the first form of property. The value of things was measured in terms of food. "Primitive migration was always after food, food for men and food for cattle, which in turn was food for men." 4 Ceremonials, religion, manners and laws grew in close rela- tion with food. Food was the first thing desired and fought for. 1 Parker, Carleton; Casual Laborer and Other Essays, 1920. 2 Cannon, W. B.; Bodily Changes in Pain, Hunger, Fear and Rage. 1920. P. 232. 3 McDougall, Wm.; Introduction to Social Psychology. 1908. P. 72. "Hall, G. S.; Adolescence. 6 AN EXPERIMENTAL STUDY OF HUNGER The earliest education and habit formation of children begin also with regard to food. Psychological tendencies, such as acquisition, pugnacity, rivalry, jealousy, sympathy and gratitude display themselves in connection with food, and more or less "condition" or determine the future character of the child. Thus food is a matter of great concern in infancy and childhood. Ex- cept when in need of food, a healthy infant is asleep. With the onset of hunger the sleeping baby awakes, wriggles and cries. If food is not given him he struggles more and more. His eyes wide open, his mouth moving or chewing anything at hand, he cries with all his might, hands clinched tight, face red, hot, and often perspiring, legs kicking, or drawn up tightly to his body. Often, too, his back is bent, and stretched. The whole organism is struggling. G. Stanley Hall 5 says, "the true be- ginning of a psychology essentially genetic is hunger, the first sentient expression of the will to live." This must be the "Elan Vital." As soon as food is given, the infant sucks it with such power that often he cannot wait to breathe. The whole organism is in a state of readiness and tension. The swallowing reflex takes place as soon as any particle is placed on the tongue. Very soon food and sucking are coupled together, and this becomes an es- tablished habit. But before that, all kinds of efforts and errors are made to satisfy this great drive of hunger. We often see babies chewing the edge of a blanket, and more often, their own fingers. In animal psychology it is a well known fact that rats, chickens, cats, and dogs do not take any interest in solving puzzle cage problems unless they are hungry. The varying food habits and hunger behaviors of different species of animals are very inter- esting in relation to their environment. As Rogers 6 did in 1916, Pavlov 7 recently proved by the following experiment that a greater part of the alimentary center is situated below the cerebro-hemisphere, and controls hunger behavior, more or less independently of the central nervous system. "A decerebrated pigeon remains immovable for hours in the middle of an abundance of food, being incapable of feeding itself. However, in such a pigeon, the activity of the alimentary center manifests itself clearly. 5 Hall, G. S.; Adolescence 6 Rogers, F. T. ; The Hunger Mechanism of the Pigeon and its Relation to the Central Nervous System. Am. Jour. Physiol., Vol. XLI. 7 Pavlov, J. P.; Sur le centre de la faim. Jour, de Psychologic. April, 1921. IN ITS RELATION TO ACTIVITY 7 We nourish him, and he takes the grains in his beak. Five or six hours after the meal, the animal begins to stir, walk about, and becomes more and more active. It is easy to be convinced that it is the alimentary center that provokes that agitation. In order that he may again become immovable for a long time, it is sufficient to catch the pigeon and make him swallow a suffi- cient quantity of grains." Thus even when there is no cortical control, hunger leads to a greater degree of motility on the part of the animal capable of locomotion, and to a greater degree of activity of the feeding reflex. Even among the lowest types of unicellular animals and plants, that possess no nervous sys- tem, hunger manifests itself strongly enough to cause visibly increased motility and cell excitability. 2. MAIN PURPOSES. What can we say about the influence that hunger exerts upon the activities of human beings? It is said that hunger, even during sleep, dominates and often controls the nature of dreams and if strong enough awakes the sleeper. Is this true? What is the effect of hunger upon muscular and mental work? Biolo- gists say that fish, that are going against a river current, and butterflies, that are undergoing great physical exertion, never feed. 8 It is a common practice among students and business men to eat but little when there is important mental work to be done. Does hunger have any influence even upon the specialized func- tions that are measured by intelligence tests? What is the in- fluence of emotional states upon hunger? Some animals refuse food, when in captivity, even to the point of starvation in the presence of plenty. Do men feel the same way in great emo- tional excitement? Such are the problems to be discussed in the following experiments. We ow r e valuable guidance in studying "instinct" to William James 9 . "The older writings on instinct are ineffectual waste of words, because their authors never came down to this definite and simple point of view, but smothered everything in vague wonder at the clairvoyant and prophetic power of the animals." He says, "The strict physiological way of interpreting the facts leads to far clearer results." Such was the method employed in the present experiment. 8 Carlson, A. J.; The Control of Hunger in Health and Disease. 1917. P. 8. 8 James, Wm.; Principles of Psychology. 1890. Pp. 383-385. 8 AN EXPERIMENTAL STUDY OF HUNGER 3. THE APPARATUS. 1. A Stomach Tube. For the purpose of registering the activ- ity of the stomach, a very thin rubber balloon of flexible quality, 4 cm. in diameter, and from 12 to 13 cm. in length, was chosen. This balloon was connected with a rubber tube of 3 mm. diameter and of any desired length. A very small metal tube was inserted at one end of this tube, and the rubber balloon was tied over it with silk thread. The metal tube made the connection firm, yet did not close the rubber tube. A little rubber cement was used in order to have the rubber balloon attached firmly and smoothly, so that the edges of the balloon would not irritate the throat, when the subject swallowed it. A number of such stom- ach tubes were kept ready. They were disinfected before use, and were kept in running water, in order to preserve the good quality of the rubber. When the air was sucked out, the balloon and the tube were very small, and could easily be swallowed. Infants usually swallow them even more easily than adults. 2. A Recording Apparatus. This apparatus consisted of a U tube 2.5 cm. in diameter and 22 cm. in height, half filled with water. One limb of this manometer had a floating marker which consisted of a thin cork, an aluminum plate 12 cm. long and 2 mm. wide, with a thin celluloid flag on top of it, and a cork adjuster on the upper end of the U tube. The other limb of the mano- meter had a rubber cork from which a rubber tubing reached to a glass bottle 17 cm. high. (See Figure 1.) When the subject was in the desired position, he swallowed the tube, which was connected with the recording apparatus. The other end of the stomach tube was connected with another rubber balloon of the same kind (B), which was enclosed in a glass bottle (D). The experimenter blew through the adjoining tube (C), which distended the balloons in the stomach and in the bottle and then closed it with a clamp. The air pressure in the bottle forced the water up in one limb of the U tube (E), and forced up a floating marker (F). The experimenter opened the clamped tube (G), and let the air escape until the water in the manometer was at the same level on both limbs, and closed it again with the clamp. Every change in pressure on the balloon in the stomach registered on the smoked paper of a kymograph. This method had certain distinct advantages over those previous- ly used. Others connected the stomach tube directly with the ITS RELATION TO ACTIVITY manometer. The result was that the air pressure in the balloon kept the manometer water unequal. Consequently the apparatus lost sensitivity. By the method here employed, the level of the water in each limb was the same at the beginning of the experi- ment and hence sensitivity was increased. Another method employed in the present experiment was to use a double rubber stomach balloon between the layers of which a bismuth coat was inlaid. Observations through a fluoro- scope made it possible to locate the exact position of the balloon in the stomach. When the balloon was inflated, the movements of the stomach could easily be observed, since the bismuth is opaque to the X-rays. Fig. 1. The Apparatus. (A) A stomach balloon, swallowed into the stomach. (B) A balloon con- nected with the stomach and enclosed in the bottle. (C) An adjoining clamped tube, to blow in the air. (D) A bottle to adjust the air pressure. (E) A manometer of U tube. (F) A floating marker. (G) A clamped tube at the bottom of the bottle. (H) A tambour registering activities on the bed. 3. In order to register the gross bodily activities of a man or an infant during the day or night, a tambour 5y 2 cm. (2% inches) in diameter, and 2 l / cm. (i/ in.) in depth was used. This tambour was covered with a rubber dam of good quality and fairly thick. A thin metal disc, 3 cm. (Ij/g in.) in diameter was shellacked in the middle of the rubber membrane, and on this disc a 2 cm. (% in.) flat-headed wooden screw, with the pointed end up, was attached by means of wax. Fairly elastic wire was 10 AN EXPERIMENTAL STUDY OF. HUNGER made into a loose spring about four inches in height. One end of this spring was tied with cord to the stem of the wooden screw,, while the other end was attached loosely to the bottom of a spring bed. By means of a clamp on one leg of the bed, the tambour was sup- ported, and at the same time xan be adjusted according to the weight of the subject, so as to keep the tambour at the maximum of sensitivity. The rubber tube from the bottom of the tambour was connected to a Marey tambour to register the body move- ment on the smoked paper. In earlier experiments, from three to ten tambours were used, distributed at different points of the bed. But experience showed that one in the proper position was just as sensitive, if not more so. (Fig. 1. H.) For the experi- ments with infants, the tambour, without the adjusting wire spring, in direct contact with the bottom of the baby bed, or carriage,. was found more sensitive. 4. The kymograph that was used was the extension kymo- graph, on which paper 7 feet 10.5 inches (94.5 in.) long could be placed. A speed of 20 inches per hour was usually used. Faster and slower speeds were tried, with the result that this speed was found to be the most accurate and convenient. Every 4^4 hours changes of paper had to be made. When the experiment was carried on throughout the night the paper had to be changed only once, at midnight. 4. THE SUBJECTS. . T. W., a woman student in psychology. Subject C. P. R., a research man in psychology. Subjects H. R. B., T. W. C., and H. E. H. were graduate stu- dents in medicine in Johns Hopkins University. All of them were healthy, vigorous young men. Patient Z., a young woman, in the Phipps psychiatry clinic, suffering from chronic hypochondria. Patient Y., a young man of the clinic, suffering from gen- eral weakness and inability to work. Baby Ann R., born February 13, 1921. She was nine months old, weighing 18 pounds, at the time of the experiment, which was conducted from November to January, 1922. Baby Barbara P., born on November 10, 1921, was one month old when the experiment was begun on December 28th. She weighed 11 pounds 9 ounces at the end of the experiment. Feb- ruary 2, 1922. Sixty Albino rats, of different sex and ages, were under the IN ITS RELATION TO ACTIVITY 11 writer's care from April to June, 1921. Observations on other rats were made also. 5. THE MAIN EXPERIMENTS. The first set of experiments here presented concern them- selves with the nature of hunger. Neurological study of the autonomic and the sympathetic nervous systems was carried on, as well as anatomical study of these systems, and of the stomach muscles. The dynamic phases of the problem were studied by direct measurement of the activity of the stomach. Varying forms of stomach activity were recorded on smoked paper by means of a special apparatus. The frequency and dura- tion of contraction periods were studied. The results presented in Chapter II show the general facts concerning stomach activity. The next step, described in Chapter III, is to find the correla- tion between hunger states and other physiological conditions, especially in respiration, vasomotor changes, and salivary secre- tion flow. The third experiment, recorded in Chapter IV, is to determine the sensation of hunger and its relation to hunger contractions. Chapter V introduces the measurement of the gross bodily movements of men during sleep. These results were analyzed and compared with the results of similar experiments tried during the day. The experiments were extended to infants, whose activities were measured during the day and night. Fi- nally rats were subjected to general observation. Mental activity during sleep was studied through the experi- ments with dreams which are presented in Chapter VI. Experiments to ascertain if there is augmentation of muscular work by himger contractions are presented next, in Chapter VII. The hand dynamometer measurements were correlated with the hunger states. Chapter VIII deals with the correlation of hunger states with mental work in Thorndike mental examinations. Chapter IX discusses the results obtained from a series of experiments in which various stimuli were introduced. Me- chanical stimuli, drugs alleged to have power to relax smooth muscles, conscious effort, the thought, sight, and smell of food, were given. These results throw light on the origin and control of hunger contractions. Stimuli of still stronger kinds, such as electric shocks, rotation, prolonged work and reading exciting stories were introduced, and the effects of these activities upon hunger states were measured. 12 AN EXPERIMENTAL STUDY OF HUNGER CHAPTER II. THE NATURE OF HUNGER. 1. HUNGER MECHANISM. 1. A Brief Description of the Stomach. The stomach is a pear shaped organ, situated in the epigastric region of the body, with three chief parts, the fitndus, the body, and the pyloric portion, which is located at the right extremity of the stomach. The region where the oesophagus enters is known as the cardiac, and the junction with the intestine is called the pylorus. The musculature of the stomach consists of non-striated fibres of three kinds, namely, the longitudinal, or outer layer, the circular layer, and the middle layer. The middle layer is lined by the sub- mucous coat, and finally by the mucous coat. 2. Nervous Control of the Stomach. It is generally maintained that the vagi nerves are the main afferent pathway for the hunger impulses. The vagi nerves have their nuclei in the fasciculus solitarius, in the medulla. The efferent vagi motor fibres come to the stomach from medulla nuclei. There are reasons for believing that the vagi and the sympathetic (splanchnic) nerves, which come from the coeliac ganglion, regulate the tonus of the stomach, one as accelerator, and the other as inhibitor. Some main- tain that both nerves have accelerating and inhibiting fibres in them- selves. Experiments have been repeatedly made to show that when either the vagi or the splanchnic nerves are cut, separately, or both together, the stomach keeps its movements without much disturbance. There are some other nerve fibres, such as the plexus of Meissner, between the submucous layers, and the plexus of Auerbach, between the longitudinal and circular, muscular layers. These intrinsic plexus seem to be capable of maintaining the movement of the musculature, independently of the extrinsic nerve.* The real origin of the gastric hunger contractions is not yet definitely established. Some maintain the myogenic theory, and some the neurogenic theory of the intrinsic plexuses. Chemical changes in the blood also has been considered as a possible cause of the gastric contractions. Though * Muller, L. R.; Das Vegetative Nervensystem. 1920. Pp. 127-134. IN ITS RELATION TO ACTIVITY 13 the periodicity of the hunger rhythm and the abrupt cessation of the contraction periods do not parallel with the fact that the chemical or starvation changes in the blood are more continuous, yet the hypothesis can not be altogether abandoned. Especially, such an internal secretion as that of adrenalin may act with certain periodicity upon the stomach walls and the intrinsic nerve plexuses and start the hunger contractions at the same time this chemical change is affecting the other parts of the organism. 3. Hunger Contractions Versus Digestive Contractions. Howell* says that the chief difference in character between the digestive and the hunger contractions seems to lie in the fact that the former involves mainly the antral end, while the latter are de- scribed as starting from the region of the cardiac orifice, spreading as peristalic waves over the whole stomach. Digestive movements occur a few minutes after the entrance of food. Small contractions start in the middle region of the stomach and run to the pylorus. The fundus end of the stomach is not actively concerned with these movements, but serves rather as a reservoir for the food, while the muscular pyloric region is the apparatus that triturates and macerates the food, and forces it out from time to time into the duodenum. Hunger contractions start in the cardiac end of the stomach, and proceed towards the fundic region. Gradu- ally the contraction waves cover a larger and larger space. From A lay 10th to 14th observations were made, through a fluoroscope, of the stomach movements of the young woman patient, Z. From May 18th to 20th a young man, Subject Y., was under observation. These observations verified the above statement of the activities of the stomach, its advancing waves, and the portions involved. 2. ACTIVITIES OF THE STOMACH. By means of the above mentioned apparatus the writer measured the activities of the stomach. When the apparatus was very delicate the following typical states were recorded: 1. The respiration pressure rhythm. When the stomach is in atonic condition there is no movement at all. Consequently the record shows only respiration. Almost uniform ups and downs on the level are to be seen, as shown in Figure 2. This complete atonic condition is very rare except immediately after vigorous contractions, or after a little water is taken. * Howell; A Text Book of Physiology. 1921, P. 721. 14 AN EXPERIMENTAL STUDY OF HUNGER Fig. 2. The respiration pressure rhythm. 2. The pulse pressure rhythm. When the respiration is held for a few seconds, or when the stomach pressure gets so low that the floating marker goes down to the limit and does not record respira- tion, the pulse rhythm is recorded. (See Fig. 3.) Fig. 3. The pulse rate rhythm. 3, The tonus rhythm. The stomach is usually in tonus condition, and often with tonus waves of great uniformity. (See Fig. 4.) These tonus contractions of the fundus gradually increase in ampli- tude, as well as in rate. (See Fig. 5 A, B, C.) Fig. 4. The tonus rhythm. 4. The powerful hunger contractions. Gradually increased tonus reaches to the hunger contractions. The duration of this contraction IN 775* RELATION TO ACTIVITY Fig. 5. A., B. and C. 15 A. Beginning of tonus rhythm. B. Gradual increase of amplitude of tonus rhythm. C. Gradual change of rate and amplitude of tonus rhythm. 16 AN EXPERIMENTAL STUDY OF HUNGER is usually from 30 to 40 seconds. (See Fig. 6.) The recorded amplitude of the contractions depends upon the size of the stomach balloon and of the manometer, as well as upon the extent to which the balloon is distended. In the present experiment, however, these factors were controlled so as to be as constant as possible. Quite often records reached to twelve centimeters in amplitude, the maximum of the apparatus. Contractions were still more powerful, and pushed the marker to the top, and water kept running over the manometer for some minutes. Fig. 6. The contraction rhythm. 5. The tetanus ending. The powerful hunger contractions some- times end with tetanus, or prolonged contractions. (See Fig. 7.) This is especially the case with prolonged starvation. After the strong contractions, an abrupt drop into atonic, or weaker tonus. conditions, often follows. (See Fig. 8.) The strength of the hunger contractions may be measured in terms of the amount of water pushed up by the gastric pressure. A con- traction that recorded a height of one inch on the smoked paper pushes 20cc. of water in a U tube of which diameter was 2.5 cm. The strongest contraction that the apparatus could record was 5 inches in amplitude, which had power to push up 100 cc. of water. Tables I and II contain results of experiments during the night and the day. They explain the duration of quiescence and tonus, the number and duration of contraction periods, and the amplitude of the contractions. (See Figs. 9, 10.) IN ITS RELATION TO ACTIVITY 17 Fig. 7. The tetanus ending. Fig. 8. The abrupt drop from contraction to quiescence. Distribution of these different states of activity varies a great deal according to the individual's general physical condition, his rate of metabolism, caused by physical and mental work, and his food habits. However, a rough average of all records show the following features : 18 AN EXPERIMENTAL STUDY OF HUNGER bfi to IN ITS RELATION TO ACTIVITY 19 from 2 to 3 hours after a meal there appear tonus waves which last from 30 minutes to one hour. They increase in amplitude and rate, and become gradually stronger contractions. An average number of the contractions is between 20 and 40 during a period which extends from 30 to 60 minutes. 20 AN EXPERIMENTAL STUDY OF HUNGER TABLE I. Showing the Activity of the Stomach for Various Subjects During the Night. Duration Time of Duration of Contraction Duration of Aver. Amp. of No. of Date Subj. Started Quiescence Tonus Period Contrac. Contrac. Contrac. 1921 Mar. 23 B 10:40 :40min. :35 min. 12:15-12:30 :15 min 1.5 in, 6 :30 1:00- 1:30 :30 2. 12 :30 :30 4:15- 5:45 :30 3.25 15 :45 :15 5:30- 6:15 :45 2. 6 Mar. 24 B 10:30 2:15 2:00 3:45. 4:45 1:00 4.25 40 5:15- 5:30 :15 2. 8 Mar. 25 B 11:30 :20 11:50-12:10 :20 1.25 12 12:25-12:45 :20 1.50 10 JOS 12:55- 1:25 :30 1.50 32 :45 2:05- 2:55 :50 2.5 49 "1 5 3:20- 3:55 :35 1.5 20 i30 4:00- 4:40 :40 3. 31 Apr. 13 B 10:30 :15 2:45 1:30- 2:00 :30 1.5 10 1:45 3:15- 3:30 '1 5 1.75 10 4:15- 4:45 30 3.75 23 6:30- 6:45 :15 2.75 10 :15 :45 Apr. 20 B 10:30 :30 1:30 :30 2:00- 2:30 :30 2.5 19 1:30 5:10- 5:15 :15 2. 15 5.30- 5:45 :15 3.75 22 :30 6:30- 7:00 30 4. 18 7:00- 7:30 :30 4.5 19 Mar. 25 H 10:45 1:20- 1:35 15 2 7 1:45- 2:20 ":35 2. 15 :10 3:45- 4:15 :30 4.25 20 4:30- 5:00 :30 3. 9 Mar. 28 H 11:00 Mar. 30 H 10:30 :30 1:15 12:15-12:30 :15 2. 10 :45 1:15- 1:30 :15 2. 12 . 15 1:45- 2:15 :30 3. 14 :20 2:30- 2:45 15 3.25 11 :30 4:10- 4:30 140 3.5 18 4:45- 5:15 :30 3.5 8 15 :15 5:15- 5:45^ 1:00 4.5 21 June 10 H 11:50 :30 12:30- 1:15 :45 2. 30 :30 1:35- 1:40 :05 2. 8 :20 2:00- 2:30 :30 2. 15 2:30- 3:15 :45 4.5 45 :45 :25 4:25- 5:30 1:05 5. 47 :45 6:20- 6:50 :30 5. 25 June 11 H 11:19 :30 :30 1:00- 3:20 2:20 4.5 145 :30 4:00- 4:30 :30 3.5 26 30 5:10- 5:25 1 5 4. 18 :45 6:10- 7:10 lioo 4.5 45 June 7 C 11:10 2:00 1:00- 1:30 :20 2.5 20 1:40- 2:00 :20 2.25 16 30 :30 4:30- 4:50 :20 4.5 16 :30 5:30- 6:00 :30 3.5 19 1:00 :15 7:40- 8:00 :20 2.5 16 June 8 C 11:50 1:15 :30 1:30- 2:30 1:00 3. 40 1:30 4:00- 5:00 1:00 2.5 40 :30 :10 5:30- 6:10 :40 3,5 34 20 6:40- 7:00 :20 3. 7 7:05- 7:20 :15 2. 8 June 9 C 11:50 :30 1:00- 1:25 :25 2. 41 :45 :20 2:20- 2:30 : 10 2. 11 2:45- 2:55 :10 2.5 9 10 3:05- 3:10 05 2. 7 20 3:30- 4:15 :45 2. 30 4:20- 5:00 :40 5. 43 :30 15 5:45- 6:10 :25 3. 28 20 6:30- 7:10 3.5 32 35 IN ITS RELATION TO ACTIVITY 21 TABLE II. Showing the Activity of the Stomach for Various Subjects During the Day. Time Duration of Duration of Contraction Duration of Aver. Amp. of No. Date Subj. Started Quiescence Ton us Period Contrac. Contrac. Contrac. 1920 July 30 W 3:35 3:40- 4:15 :35 min 3. in. 12 :05 4:30- 5:00 :30 3. 20 :30 5:45- 6:25 :40 3. 21 :30 :45 8:00- 8:30 :30 3. 19 :20 8:50- 9:40 :50 3. J2 1921 Apr. 10 B 10:30 :10 2:00 : 10 1:00 Ir30- 1:45 :15 2.5 9 1:00 1:00 4:20- 4:30 10 2 8 :30 5:00- 5:50 :50 3.5 31 1:00 lune 6 B 9:45 1:00 1:00 11:30-11:40 :10 3. 3 Apr. 9 H 3:40 :10 :10 4:10- 4:30 :20 1.0 15 :10 10 4:50- 5:15 :25 1.5 22 :15 :20 5:50- 6:20 :30 1.5 25 Apr. 14 H 4:40 :30 :30 5:40- 5:45 :05 2.5 2 Apr. 18 H 4:30 10 :30 :20 5:00- 5:30 :30 2.5 26 1:00 Apr. 22 H 5:00 :10 5:10- 5:50 :40 3.5 25 l!20 Apr. 24 H 9:00 1:00 :20 9:00- 9:30 :30 4.5 16 11:20-11:35 : 15 4.2 14 :45 12:35-12:50 :15 4.2 12 :40 ':30 3:00- 3:15 :15 4.2 16 :30 15 2:00 1:00 5:30- 6:00 :30 4. 17 1:00 :30 Apr. 26 H 4:40 :30 :30 5:00- 5:15 :15 2.7 15 1:30 May 8 H 9:00 :30 :20 1:25 12:00-12:30 :30 2. 15 12:45- 1:25 :45 4.5 28 :35 30 2:30- 2:45 :15 2. 12 :45 3:30- 3:40 : 10 1.5 6 :50 4:45- 5:00 :15 2.5 17 1:00 May 21 H 4:00 :20 4:20- 4:50 :30 2. 28 :20 5:10- 5:40 :30 2.5 25 :15 5:55- 6:10 :15 2. 12 June 9 H 9:00 -.30 2:30 12:00-12:40 :40 3. 27 :20 1:20- 1:55 :35 4.5 22 1:00 1:35 4:30- 5:00 :30 3.5 21 :15 5:15- 6:00 :45 4.5 34 Apr. 3 C 11:30 2:20 1:20- 1:30 10 2. 6 1:00 :50 3:30- 3:50 ':20 2 2 11 1:10 5:00- 6:00 1:00 3.5 52 Apr. 15 C 4:15 1:15 :45 2.2 3 Apr. 16 C 3:30 1:00 1:30 Apr. 17 C 10:15 :30 10 11:10-11:40 :30 3. 20 1:30 !30 1:10- 1:25 :15 3. 14 Apr. 19 C 4:20 1:00 :30 22 AN EXPERIMENTAL STUDY OF HUNGER TABLE II. (Continued) Date 1921 Subj. Time Started Duration of Quiescence Duration of Tonus Contraction Period Duration of Contrac. Aver. Amp. of Contrac. No. Contrac. Apr. 21 C 4:55 :30 5:30- 5:40 10 4. 10 :30 :30 5:10- 5:55 145 4.2 21 Apr. 23 C 1:30 :30 :30 1:30- 2:10 :40 3.5 46 2:45- 3:20 3. 42 :20 :20 4:00- 6:10 2:10 3.7 22 Apr. 25 C 4:33 :45 5:30- 5:40 :10 2. 7 :20 5:45- 6:00 :15 2.5 13 :45 Apr. 27 C 6:52 :30 :30 May 15 C 10:05 1:00 1:00 1:00 :20 1:20- 1:40 :20 2. 12 1:00 2:40- 3:00 :20 3. 16 :20 4:30- 5:00 :30 2. 3 June 5 C 1:45 :40 1:30 5:15- 5:45 :30 3. 26 June 7 C 9:30 1:35 :15 11:20-11:45 :25 2 18 :25 ; JO IN ITS RELATION TO ACTIVITY 23 CHAPTER III. CORRELATION OF THE HUNGER RHYTHM WITH OTHER PHYSIOLOGICAL CONDITIONS. 1. RESPIRATION. The stomach balloon registers very sensitively the effect of respira- tion upon the stomach. Another method of measuring respiration on the chest by means of Marey's pneumograph was tried on Subject C from 1 :45 to 6 P. M. on June 4th. All results show that there was no specially deep or shallow breathing at the time of the contraction. 2. VASOMOTOR VOLUME. For four hours a record of the- glass plethysmograph on the right arm of Subject C was taken simultaneously with that of the stomach. In periods of tonus conditions of the stomach, the rhythms of the plethysmograph record correlate closely with the ups and downs of the tonus. The vasomotor changes shown in the plethysmograph records looked as if they followed closely the ups and downs of the stomach record. But the powerful hunger contraction waves did not correspond to the rhythm of vasomotor changes recorded "by the plethysmograph. 3. SALIVARY SECRETION. In the experiment on July 30th, Subject W went through a twenty hour starvation period. On the occurrence of each contraction period there was an abundant secretion of saliva. Her mouth became so filled with the secretion that she had to expectorate several times. This never happened in quiescent periods. An improved method of regis- tering the salivary flow of Stenson's duct was devised by Dr. C. P. Richter, together with the present writer, by joining to the metal can- nula for collecting secretion, a long, narrow glass tube, which was placed on a yard stick. The measurement of air bubbles through the tube was recorded as the secretion flowed. By using this method, to- gether with the stomach tube, one can measure the correlation between the salivary secretion and the state of hunger. Owing to the dis- comfort of keeping both pieces of apparatus in the mouth for a long time, this experiment was abandoned. 24 AN EXPERIMENTAL STUDY OF HUNGER In the experiment of conditioning salivary secretion to the sound of a bell, by using carbolic acid, lemon juice and chocolate, it was found that immediately after a meal conditions were unfavorable for the experiment because little saliva could be obtained for several hours. Pavlov reports an experiment by Nikifrovsky, of retarded conditioned reflex of the salivary secretion of a dog. Introduction of acid solution three minutes after the appearance of a strong light was repeated, so as to establish this three minutes' retarded con- ditioned reflex. "It is at 5 P. M. that we distribute food to our dogs : if we make an experiment of retarded reflex at 10 A. M., salivary secretion does not appear until the end of three minutes. But if we bring over the same experiment at 3 or 4 P.M. we cannot obtain the retardation." This fact shows that the gland is more ready to secrete saliva when the dog is hungry. Thus Pavlov points out the close relation between the salivary secretion center and the hunger center. It is a common observation that people have abundant saliva in the mouth when they are hungry. The writer's experience agrees with the statement of Carlson* that there is a rhythm of the salivary flow parallel to the gastric hunger contraction rhythm. He goes further to say that each hunger contraction is accompanied by a brief gush of saliva from the duct. CHAPTER IV. CORRELATION OF THE HUNGER RHYTHM WITH THE SENSATION OF HUNGER. The apparatus was so arranged that the subject pressed an electric magnetic button, which registered the appearance of the sensation of hunger. At the same time, the activity of the stomach was re- corded. This is the well known Cannon- Washburn experiment, and was repeated in the present study only to confirm the result. On April 23rd, Subject C came to the laboratory at 1:15 P.M., without luncheon, and his sensation of hunger was recorded in the above mentioned way. The experiment was carried on up to 6 P. M. He pressed the button at three different contraction periods, as fol- lows: 10 signals at the 3:20 contraction period, 5 at 4:10, and 6 at 4:50. All of the signals occurred at the height of a contraction. No sensation of hunger was recorded at quiescent periods. * Carlson, A. J.; "Control of Hunger in Health and Disease". 1916. Pp. 90-91. ITS RELATION TO ACTIVITY 25 be 26 AN EXPERIMENTAL STUDY OF HUNGER Subject H underwent the same experiment, on April 24th, for 9 l /2 hours, starting at 9 A. M. His record was as follows: 6 signals at 11 :30, a tonus period, 2 at 12, at the beginning of a contraction period, 4 signals at 1, at the end of the contraction period, 5 at 1 :25, 4 at 1 :35, both in tonus periods, and 4 signals at 5 :30, at the height of contractions. These results show that the sensation of hunger occurred simul- taneously with the contraction of the stomach. However, observa- tions made in these experiments showed that, when the contraction became chronic from lack of food for several hours, the sensation became diffused, and the subject failed to appreciate each hunger con- traction. In the first case of the above mentioned experiments, Sub- ject C had one long continuous contraction period, from 4 to 6 P. M. He signaled only 11 times at the heights of the largest contractions, while the number of contractions counted over 140. This experiment was repeated on May 16th with a young woman patient, Z.,* whose complaint was that she was never hungry because her stomach was weak and could not digest any food. She lay down on a bed, and pressed a button in the same way as the other subjects. The experiment was started at 10 A. M. She had a contraction period from 10:20 to 11:30, and another one at 12:35, which con- tinued until 2:10, lasting one hour and thirty-five minutes. These contractions were of great amplitude and recurred rapidly. In this case of incessant and chronic contractions, also, the patient failed to perceive some of the weaker contractions. Patient Y., a young man, was the subject of this experiment on May 17th and 20th. He had morning and noon hunger contraction periods. He discriminated each sensation of hunger at the height of each contraction. A sensation of dull weakness, headache, and sometimes of nausea, is felt when the hunger pang is left unsatisfied for a long time. This seems to vary greatly in different individuals. Within the knowledge of the writer, some individuals say that they never had a hunger pang in their life, while, on the other hand, others speak of having had, at times, so strong a hunger pang in the epigastric region that they could not sit still, but had to go out to get something to eat. The origin of the sensation of hunger was thus established as being the muscular contractions of the stomach. * This experiment and some others following were made possible by the co-operation with Dr. C. P. Richter. IN ITS RELATION TO ACTIVITY 27 CHAPTER V. CORRELATION OF THE HUNGER RHYTHM WITH BODILY ACTIVITIES. 1. BODILY MOVEMENTS OF MEN DURING SLEEP. From March 9th on, every night for a week, Subject R slept on the bed that registered all his bodily movements during sleep. The stomach tube was not employed in this study. The tambour system was made so sensitive that even his finger movements were registered at the beginning of the experiments. The results were studied by putting on a chart the number of body movements made. It was found that the activities fell into distinct groups, and that these groups came with certain periodicity. Figure 12 shows a part of the periodical groups of the activities. Another interesting discovery was that, when the subject had taken a glass of milk before going to bed, he was much less active in the early part of the night than when he went to bed feeling hungry, but without the milk. Compare Fig. B, which is the record of the night when he had the milk, with C and D in Fig. 12. These facts suggested the possible correlation between stomach activity and general bodily activity. 2. CORRELATION OF HUNGER RHYTHM WITH BODILY MOVEMENTS OF MEN DURING SLEEP. A second group of experiments was started on March 23rd when the subject had become thoroughly accustomed to swallowing the stomach tube. Subject B swallowed the tube and then went to bed in one of the quiet rooms of the laboratory, where the ventilation and heating were favorable. The tubings from the bottom of the bed, together with that from the stomach, were led through a hole in a thick door into the next room, where the experimenter adjusted them to the recording apparatus. The machine operated throughout the night without disturbing the sleep of the subject. Fig. 13 shows the results. The subject had dinner at 6 P. M., studied until 10:30 and then came to the laboratory to have the experiment started at 10:45. The stomach was in a quiescent state for one-half hour, then it gradually began to have more and more tonus rhythm. At 12:15 there appeared some bodily movements, none of which had appeared hitherto. At 12:30 the experimenter observed that the body move- 28 AN EXPERIMENTAL STUDY OF HUNGER Fig. 12. The gross bodily movements in quantitative measurement. merits occurred simultaneously with the stomach contractions. A few minutes later the stomach fell again into the quiescent period, only to resume a tonus condition within fifteen minutes. The second contraction period began five minutes before 1 A. M. Most of the body movements occurred at the heights of stomach contractions. IN ITS RELATION TO ACTIVITY 29 30 AN EXPERIMENTAL STUDY OF HUNGER There were two more definite contraction periods at 4:15-45, and 5:30-6:30. At the end of the last contraction the subject got up of his own accord, and the experiment was stopped. The subject said that he had slept well, without discomfort from the swallowed tube. The experiment was repeated on the following five nights. With slight modifications, bodily activities of men during sleep were recorded on thirteen nights. Photographs of actual records testify to the simultaneous occurrence of the bodily activities and hunger contractions. (See Fig. 13.) 3. CORRELATION OF THE HUNGER RHYTHM WITH BODILY MOVEMENTS OF MEN DURING WAKING STATE. On April 23rd a record of the bodily movements of Subject C during the day was taken. He had eaten nothing since breakfast. At 1:15 P.M. the experiment was started, the subject lying on a .couch, and reading "Moon Calf." He had contraction periods from 1 :30 to 2:10, and from 2:45 to 3:20, also from 4 to 6:10. Bodily activities occurred almost simultaneously with the stomach contrac- tions, as in the night experiments. (See Fig. 14.) Fig. 14. Bodily movements of men during waking state. On May 8th, Subject H had no breakfast, and was experimented on from 9 A. M. to 6 P. M. in the same way. He had the following contraction periods: 12-12:30, 12:45-1:25, 2:30-2:45, 3:30-3:40, 4 :45-5 :00 P. M. There were numerous bodily movements during the contraction periods, while practically none of them appeared at quiescent times. Since this was a whole day experiment, with five contraction periods, the result was confirmatory in showing rhythm- ical activity periods during the day, when the subject was relatively free from external stimuli. 7A f ITS RELATION TO ACTIVITY 3i 4. BODILY MOVEMENTS OF INFANTS. The tambour apparatus was so set underneath a small bed as to register the bodily activity of Baby Ann. From November 9th, the night activities were taken. It was necessary to have a baby whose feeding habits were regular. Baby Ann had been brought up under ideal conditions. Since she was ten months old her feeding periods had remained unchanged. They were as follows: 7:30 to 8 A.M., 11 :30 to 12 M., 3:30 to 4 P. M., and 8:30 to 9 P. M. She received 8 ounces at the first feeding, then 10 ounces, again 10 ounces and at the last feeding 8 ounces of milk. She was put to bed at 9 P. M. in a quiet nursery, and was not touched until the morning feeding period. Records show very marked periodicity of activity; about once in forty-five minutes she wriggled in her sleep, and towards morning activity increased, but without changing the periodicity. These experiments were repeated for ten nights and the results con- firmed the periodicity. (Fig. 15.) Fig. 15. Activities of infants. Baby Ann (9 months old), during the night. 11 P. M. 8 A.M. Baby Barbara slept in a carriage instead of a crib. The tambour, which was placed underneath the body of the carriage, registered the baby's activity sensitively. Since she was very young there was no marked difference between the activities of day and night. She slept on, excepting when she was fed at 6:30 and 10:30 A. M., and at 2 :30, 6 :30 and 10 :30 P. M. For some time after the night feeding the baby was, according to the record, very quiet. At intervals of about once every 40 minutes, she made bodily movements which in- creased in frequency and vigor toward the morning until the next feeding, which came at 6:30. These periods depend upon the quantity and quality of food given, as well as upon the health conditions and the digestive capacity of the child. However, we may well predict regular activity periods as the time for feeding draws near. In the case of Baby Ann, change of diet by a small amount of oatmeal and orange juice in the course of the ten day experiment did not affect the activity and hunger periods. As the age increases food habits change, and consequently, the bodily activity periods. * 32 AN EXPERIMENTAL STUDY OF HUNGER Day activity records were taken for three consecutive days. The infant Ann was kept in the nursery with several toys, while any out- side stimulus, such as a sight of the parents, was avoided. The feeding periods were strictly kept. The results showed that the day activities also fell in periods of about 45 minutes. 5. BODILY MOVEMENTS OF ALBINO RATS. About 200 Albino rats were kept in the laboratory for observation and experimentation. Some 60 white rats were under the writer's care and observation from April to June, 1921. Thirty of them were 3 weeks old, and 15 were 3 months old, while the rest were 5 months of age in April. About l /$ of each group were females. They were kept in cages and fed once a day at 12 M. Their hunger behaviors were closely observed. At the time of feeding, the rats appeared to be extremely hungry. The young ones, especially, pushed each other at the gate, climbed on top of each other, and jumped up and down on the wire cloth of the cage. The older ones sniffed and smelled the milk, and bit the wire at the gate with their teeth. After the trial in the maze, they were provided with food, which made them more excited. They fought, they screamed, and finally they snatched away a piece of bread and ate it most eagerly. After they ate enough, some of them would take pieces away from others and pile them up in a corner, often under the saw dust. The older ones would go to the nook and sleep, while the young ones played and ran after each other for a while and then would take a nap. Even the older ones woke up several hours after the feeding, and the activities of the rats gradually increased toward the next feeding period. By the measurement of his rats, Dr. Richter 1 found that the free activities of the rats came with certain periodicity. To the bottom of a triangular cage were affixed three tambours which registered on the smoked paper by means of tubing all the activities of a rat. When the rat was kept in a quiet and dark room, spontaneous activities fell in definite groups. Until about 7 days after birth, records showed no definite periodicity. 2 Activities were quite constant. But after a rat had been fed sufficiently to keep it from getting hungry for a time, it would not feed for about 30 minutes. Thus, on the 7th day, the record began to show periodicity. There was a definitely active period about once every 30 minutes. As the size of the rat, as well as the stomach increased, these periods came less frequently once 1 Richter, C. P.; Behavioristic Study of the Activity of the Rat. 1922. 2 The author was permitted to mention some part of the unpublished experiment by Mr. G. H. Wang. IN ITS RELATION TO ACTIVITY 33 every 40 to 50 minutes, but the amount of activity became greater. The rat often became very vicious when hungry. Very old rats, however, were observed to be much less active, and less frequently active. A suitable stomach balloon was made, and several trials were made to measure the stomach activity of a rat. On April 30th, the stomach tube was successfully put in a large sized and very tame rat. But the rat made every possible effort to pull the tube out. Under such abnormal conditions it was impossible to secure any good record, except a faint respiration mark. Nevertheless the correspondence of hunger and activity periods of white rats under laboratory conditions is rendered very probable by the above results. CHAPTER VI. CORRELATION OF THE HUNGER RHYTHM WITH DREAMING. The extent to which the gastric hunger contraction affects the mental status of the sleeping man was investigated in connection with dreaming. On June 8th, Subject C came to the laboratory having had dinner at 6 o'clock. At 11 :50 P. M. he went to sleep with the stomach tube. At 1 :30 A. M. there was a contraction period lasting an hour. At 2:20 A. M., that is, at the end of the contraction period, the experi- menter opened the door quietly and asked the subject if he had dreamed. The answer was, "I wasn't dreaming." At 4 A. M. there was another contraction period lasting one hour. At 4 :25 A. M. the subject was asked the same question, concerning dreaming. "Not that I know of," was the answer. From 5 :30 to 6:10 and from 6:40 to 7 :00 and from 7 :05 to 7 :20, there were contraction periods, but no question was asked. June 9th. Subject C. The contraction periods, as follows : From 1 :00 A. M. to 1 :25, 2:20 to 2:30, 3:05 to 3:10 and from 3:30 to 4:15. From 4:20 to 5:00, 5:45 to 6:10, 6:30 to 7:10. At 4:15 in the contraction period, Subject C was asked about dreams. He answered, "I had a dream, but have forgotten it." At 7:10 the answer was "Not that I know of." June 10th, Subject H starting experiment at 11:50 P.M., had contraction periods from 12:30 A.M. to 1:15, from 1:35 to 1:40, from 2:00 to 2:30, from 2:30 to 3:15 and from 4:25 to 5:30. At 4 :45 he was asked the question about dreaming. It was ten seconds 34 AN EXPERIMENTAL STUDY OF HUNGER before the subject was sufficiently awake to answer. He said that he had dreamed at about 4 :30, as follows. "By some reason or other there were red spots, an inch in diameter, scattered on the ground and as I walked toward them they came up a foot high and so thickly that I could not walk through them." The next morning he explained that he had been working at blood examinations for a month. Fig. 16. Experiments on dream. Woke in the middle of the contraction and subject had a dream. June llth, at 3:31, during a contraction period. Subject H was questioned concerning dreams. He answered, "I had a dream, but don't remember it." The experimenter questioned him further by saying, "Do you remember what kind of dream it was? Whether pleasant or unpleasant." The subject replied, "Somewhat unpleasant ; I may recall it." After a few minutes he said, "I may describe it partly: How do you want it, situation?" "Yes." "I was on a mountain, a day's journey from civilization ; each day, before I went up I took my raincoat, some food, etc. After I got there, I hung those things in a place where a foreman or superintendent kept things. By some reason or other, things were disappearing there. Whenever an earthquake occurred, things were missed. One day my things only disappeared, and I was coming back with some other men, but I did not have a raincoat and got soaking wet, but tried to be cheerful saying, 'Oh, no matter, it doesn't make any difference', and I came down." Since this was a time when many students were thinking IN ITS RELATION TO ACTIVITY 35 of going home for the vacation, the experimenter asked whether it was the subject's home mountain. "No," he said, "it was not my home state mountain nor anywhere I can recall. That is all there was, thus far." The subject fell asleep and had more contractions. There was no dream in 4 :00 to 4 :30 contraction period, when asked at 4 :22. At 5 :00 the subject dreamed that when he removed the tube his throat began to bleed and much blood spurted out : this was during the contraction period. He had another contraction period from 6:10 to 7:10 A.M. Out of seven experiments, with two subjects, on four nights, there were four dreams and two negative answers, in the contraction period. No dreams were discovered in the quiescent period. Thus far, the observations showed that there was greater tendency toward dreaming during the contraction periods than in the quiescent. Waygandt states that starving persons dream more than usual in their sleep. (Carlson '17. P. 87.) - CHAPTER VII. CORRELATION OF THE HUNGER RHYTHM WITH MOTOR ACTIVITY. In order to measure efficiency in motor activity during the hunger contraction and quiescent periods, the hand dynamometer was chosen. Other motor tests such as tapping, steadiness, co-ordination tests, and typewriting were used with three subjects for a period of three weeks. They were found to involve many variables among which the effects of practice, fatigue, and varying degrees of interest were especially prominent. The improved Smedley hand dynamometer proved the best measurement of the maximum of grip. There was no per- ceptible influence of fatigue or lack of interest when experiment was undertaken at intervals of two minutes. Adaptation to the test was provided by practice for several days by Subjects B, C, H and W. On April 18th, Subject H, without luncheon, swallowed the stomach balloon and the experiment was begun at 4:30 P.M. In order to avoid fatigue, the subject was to pull the hand dynamometer only when the order was given. The experimenter watched the record very closely and when a contraction or a quiescent period established itself definitely, she gave the order for the subject to be ready and then to pull the hand dynamometer which registered the score in terms of kilograms. Care was taken not to let the subject know the score he made at any time, but he was told to do his best. The 36 AN EXPERIMENTAL STUDY OF HUNGER measurements were made, on this day, at one contraction period, which appeared between 5 and 5 :30, and at a quiescent period, between 5 :30 and 6. At 7 P. M., after the subject had dinner, it was resumed until 8 P. M. The scores are presented in Table III with the averages andP.E. A 's. The formula is P.E.. = f ' - .6745 \ N On April 22nd, Subject H's grip power was measured at one long contraction period which lasted for 50 minutes, and at quiescent periods and also after dinner for 45 minutes. On April 24th, he started this experiment at 9 A. M., without food since the previous evening. There were four contraction periods, two in the forenoon and two in the afternoon. Altogether, eleven groups of measure- ments were obtained, one of which was taken after dinner. Table III contains all of H's scores, the averages and P.E. 's. IN ITS RELATION TO ACTIVITY 37 TABLE III. The scores of hand dynamometer of Subject H on April 18th, 22nd and 24th. The scores measured at hunger contraction periods are indicated by stars. The calculation of averages and P.E.A'S are based upon the added score of the right and the left hand. R. & L. Time Right Left Added Average 6 P - E -A April 18, A :30 P. M. 2.15 .65 1.47 .57 DINNER 7:00 P.M. 2.34 .64 April 22, 5 :00 P. M. 1.50 .72 48* 44* 92* 45* 43* 88* 48* 45* 93* 49* 41* 90* 49* 45* 94* 91.40* 48.5 41 89.5 45 43 88 49 41 90 89.17 D I N N E R 49 44 93 50 41 91 47 40 87 50 42 92 45 42 87 46 43 89 91.50 50 41 91 50 38 88 89.50 50* 41* 91* 50* 45* 95* 52* 42* 94* 49.5* 41* 90.5* 48* 42* 90* 49* 44.5* 93.5* 51.5* 43* 94.5* 50* 41.5* 91.5* 92.5* 50* 42.5* 92.5* 50* 42* 92* 50* 44* 94* 50* 42* 92* 49* 43* 92* 49* 43* 92* 48* 41* 89* 51* 42* 93* 50* 42* 92* 51* 42* 93* 49* 42* 91* 92.05* 47 40 87 46 42 88 47 41 88 46 40 86 46 42 88 87.40 D I N N E R 46.5 42 88.5 49.5 40.5 90 50 40 90 49 40.5 89.5 46 38.5 84.5 1.84 .44 5 :30 P. M. L.21 -25 6:00 P.M. 46 42 88 47 41 88 A6 Aft S^i .80 .24 DINNER 6:45 P.M. 38 AN EXPERIMENTAL STUDY OF HUNGER TABLE III. (Continued) 6 P.E.A. R& L Time Right Left Added Average 7:00 P.M. 46 37 83 47 40 87 47 39 86 ^ 47 39.5 86.5 49 39.5 88.5 49 41 90 48 38.5 86.5 47 36.5 83.5 48 36 84 47.5 39.5 87 46 39.5 85.5 47.5 39 86.5 86.85 43.5 40 83.5 41 39.5 80.5 43 39.5 82.5 43 39 82 44.5 38 82.5 45 37 82 44 38 82 44 37 81 42.5 35 77.5 40 34 74 42 35 77 80.41 April 24, 10:00 P.M. 51* 42* 93* 51* 41* 92* 50* 40* 90* 91.67* 49 38 87 49 39 88 48 42 90 49 40.5 89.5 88.62 48 37.5 85.5 48 37.5 85.5 46 39 85 48.5 38 86.5 43 36 79 46.5 37 83.5 47 35.5 82.5 46.5 37.5 84 43 37.5 80.5 46 39.5 85.5 83.75 47* 41.5* 88.5* 48* 40* 88* 49* 39* 88* 48* 39* 87* 48* 41* 89* 49* 40* 89* 88.25* 46 34 80 46.5 39 85.5 45 38.5 83.5 47 39 86 48 39 87 47 37 84 46 36.5 82.5 44 37.5 81.5 44.5 37.5 82 45 39.5 84.5 83.65 2.23 .36 2.82 .57 1.25 .49 1.19 .40 2.30 .49 .69 .19 2.07 .44 IN ITS RELATION TO ACTIVITY 39 TABLE III. (Continued) R * L Time Right Left Added Average 6 P.E.A. 12:30 P.M. 88.22* 2.21 .50 1 :30 P. M. 2:30 P.M. 47 41 88 45 41 86 47 AT. 00 86.09 2.60 .53 93.25 1.48 .50 3 :00 P. M. 48* 42* 90* 47* 38* 85* 47* 42* 89* 47* 39.5* 86.5* 45* 41*' 86* 47* 43* 90* 48* 38* 86* 48.5* 43* 91.5* 47.5* 42.5* 90* 47 41.5 88.5 43 41 84 44 41 85 46 38.5 84.5 47 41 88 45 41 86 41 39 80 47 41 88 45 41 86 47 43 90 47 40 87 50* 44* 94* 50* 45* 95* 50* 43* 93* 49* 42* 91* 47* 42* 89* 50* 45* 95* 51* 42* 93* 51.5* 42* 93.5* 50* 44* 94* 50* 45* 95* 50* 42.5* 92.5* 48 41 89* 49 41 90 48 42 90 49 42 91 49 43 92 49 41 90 47 43 90 48 41 89 49 42 91 48 42.5 90.5 48 43 91 47 44 91 50 44 94 45.5 44 89.5 50 44 94 46 41 87 49 41 90 50 43 93 44 41 85 46 39 85 45 43 88 93.14* 1.90 .48 2:30 P.M. 90.25 .87 .19 4:00 P.M. 89.77 3.10 .63 40 AN EXPERIMENTAL STUDY OF HUNGER TABLE III. (Continued) R & L Time Right Left Added Average <3 P.E.A, 5 :00 P .M. . R & L Right Left Added 44* 42* 86* 45* 43* 88* 49* 45* 94* 48* 44* 92* 47* 38* 85* 49* 39* 88* 48* 42* 90* 48* 44.5* 92.5* 48* 43.5* 91.5* 47.5* 41* 88.5* 48* 42* 90* 89.59* 2.66 .54 DINNER 7:00 P.M. 41 42 83 46 42 88 47 42 89 46 36 82 46 41.5 87.5 44.5 40 84.5 46.5 38 84.5 43 40 83 47 40.5 87.5 45 43 88 7:30 P.M. 44 43 87 85.82 2.35 .48 IN ITS RELATION TO ACTIVITY 41 On April 19th and 21st, Subject C underwent the same procedure. In all, there were obtained five groups of the contraction period scores, three quiescent and two groups of the after dinner scores. The results are to be seen in Table IV. TABLE IV. The scores of hand dynamometer of Subject C on April 19th and 21st. The scores measured at hunger contraction periods are indicated by stars. The calculation of averages and P.E.A'S are based upon the added scores of the right and the left hands. R & L Time Right Left Added Average 6 P.E.A. April 19, 4 :20 P. M. 51* 41.5 92.5 49 41 90 50 40.5 90.5 49* 43* 92* 49* 44* 93* 45* 42* 87* 50* 41* 91* 50* 41* 91* 49* 36* 85* 49* 42.5* 91.5* 49 40 89 48.5 40 88.5 48.5 39 87.5 45 38 83 45 36 81 47 34 81 45 39 84 48 40 88 47 37.5 84.5 47 40.5 87.5 50 39 89 49 40.5 89.5 51* 40* 91* 52* 44* 96* 91.00 1.08 .42 5:00 P.M. 49* 42.5* 91.5* 90.07* 2.70 .69 5 :30 P. M. 86.04 3.04 .59 6:00 P.M. 93.50* 2.50 .12 DINNER 7:00 P.M. 47 36 83 40 33 73 45 37 82 45 35 80 43.5 33.5 77 46 36 82 46 33 79 41 33.5 74.5 46 36 82 45 37 82 8 :00 P. M. 47 37 84 44 36.5 80.5 48 40 88 48 35 83 49 39.5 88.5 49.5 38 87.5 8:30 P.M. 50 38.5 88.5 82.03 4.43 .72 42 AN EXPERIMENTAL STUDY OF HUNGER TABLE IV. (Continued) R & L Time Right Left Added Average 6 P.E.A. April 21, 4 :55 P. M. 5 :30 P. M. R & L Right Left Added 39* 34* 73* 50* 42* 92* 48* 43* 91* 47.5* 41* 88.5* 52* 39* 91* 51* 40* 91* 50* 37* 87* 51* 42* 93* 50* 41* 91* 47 38 85 50 40 90 51.5 37 88.5 51.5* 40* 91.5* 51* 35* 86* 50* 35* 85* 53* 36* 89* 51* 35* 86* 50* 36* 86* 48* 38* 86* 50* 40* 90* 50* 38* 88* 49 37 86 51 39 90 48 36 84 47 36 83 45 32 77 46 35 81 47 35 82 50 36.5 86.5 45 32 77 49 36 85 48 35 83 88.6* 5.77 1.30 87.83 2.09 .81 87.50* 2.11 .47 85.75 2.68 .90 6:00 P.M. 48 35 83 81.64 3.39 .86 DINNER 7:00 P.M. 43 33 76 49 34 83 48.5 34 82.5 50 36 86 49 35 84 50 33 83 52 33 85 49 34 83 47.5 37.5 85 45 34.5 79.5 47 32 79 47 33 80 47 33 80 50 33 83 48.5 33 81.5 44 30.5 74.5 48 33.5 81.5 47.5 35.5 83 46 36 82 48 34 82 82.00 2.78 .52 7:30 P.M. 48 34 82 81.07 2.74 .70 IN ITS RELATION TO ACTIVITY 43 Figs. 17 and 18 present the curves of the hand dynamometer scores of the two subjects. The averages, which are schematically presented by the horizontal dotted lines, are higher, without exception, during the hunger contraction periods than at the preceding or following quiescent periods. Subject C's scores at the contraction periods on different days were added and v the average taken is 89.98 kilograms (P.E. A =.55). The average of all his scores at quiescent periods and at after dinner periods are, respectively, 85.64 kg. (P.E. A .49) and 81.84 kg. (P.E. A = .40). C's average at the hunger contraction periods is 4.32 kg. higher than at quiescent periods, and 8.14 kg. higher than after dinner periods. Subject H's scores on three different days were calculated in the same way. The average of his scores at contraction periods is 90.91 (P-E. A = .22). The average of his grip power at quiescent and after dinner periods are respect- ively 87.11 (P.E. A = .28) and 85.42 (P.E. A = = .40). This in- dividual can pull, therefore, at the time when the hunger contrac- tions are present. 3.80 kilograms more than when his stomach is in non-active state, and 5.49 kilograms more than when his stomach is rilled with food or is digesting it. rion contraction a, *..*, Figure 17. The curves of the hand dynamometer scores of Subject C. A star (*) indicates the hunger contraction periods and a double cross ( ^ ) the after-dinner periods. A horizontal dotted line in- dicates averages. The above experiment proves that hunger has the positive effect of augmenting the efficiency in motor activity. In other words, the rhythms of the hunger contractions and tips and downs of fluctua- tion in the motor efficiency, correlate with each other very highly. 44 AN EXPERIMENTAL STUDY OP HUNGER x > u u. i of bJO E* 3 "I 'I M-H U, C O CJ-- 3~ o as z: aJ O O S B o.S IN ITS RELATION TO ACTIVITY 45 CHAPTER VIII. CORRELATION OF .THE HUNGER RHYTHM WITH MENTAL ACTIVITY. The fifteen forms of Part I of the Thorndike Intelligence Ex- aminations were selected for the purpose of measuring the effect of hunger contractions upon mental activity. The reason for this selection was (1) that these tests have various kinds of mental functions, involving many types of materials such as words, digits, geometrical figures, etc.; (2) that these tests are sup- posed to be relatively free from the effect of practice ; and (3) that there are fifteen different forms of tests, the relative dif- ficulties of which have been determined.* The substitution or association tests, with different sets of numerals as keys, were first tried for several hours each, with two individuals, and it was found that the effect of practice was very great and also that equality in difficulty of the keys could not readily be ob- tained. Consequently, this substitution test was abandoned and the Thorndike intelligence tests were taken up. Each form of the tests was carefully studied, and the fifteen forms were put in such an order that the same kinds of tests should not be given in succession. In giving these tests, the following two problems were kept in mind : First, whether this prolonged hard mental work would affect the vigor and fre-' quency of the hunger contraction, and second, whether there would be any change in efficiency in doing this kind of mental work, according to the presence or absence of the hunger con- tractions. On May 15th, Subject C came to the laboratory without having had anything to eat since supper the previous evening. At 10 A. M. he sat before a well-lighted desk in a quiet experimental room and his stomach activities were recorded. The experi- menter watched closely and gave him an order to begin a given form and when the time was up, gave the direction, "Even if you have not finished test , begin test ." At the * Thorndike, Edward L.; Equality in Difficulty of Alternative Intelligence Examinations. Psychol. Review, 1921. 46 AN EXPERIMENTAL STUDY OF HUNGER end of 30 minutes, which is the maximum time allowed for one form of tests, the subject was permitted to rest for three min- utes and then he was given the next set. The forms A, B, F, C, G, K, D, M, H, L, I, O, E, and J were given up to 6 P. M. Form N was given at 8 :05 P. M. after the subject had had a hearty din- ner following 24 hours' starvation. In the early part of the morn- ing, in spite of the fact that nothing had been eaten for over sixteen hours, the stomach was practically quiet. There was a one-hour quiescent period followed by a tonus period at 11 A. M. which lasted one hour and dropped into another long quiescent period. No contraction appeared until 1 :20 P. M. when there were 12 contractions of the amplitude of 2 inches extending over a period of 20 minutes. One hour of quiescence followed. At 2 :40 a period of 3 inch long contractions appeared and the final hunger period came at 4:30 and lasted for 30 minutes, though the amplitude of the contraction was small. After dinner the stomach was in perfect quiescence. The accomplishment of Subject C on the tests is presented in Table V, together with the state of hunger and the expression of the subjective feeling. Fig. 19 shows the curve of his scores. The contraction periods are indicated with stars. Two of the highest scores occurred at the contraction periods. During the period when the subject reported feeling of fatigue, the stomach was quiet and the scores were relatively low, i. e. at 11 A. M. at a quiescent period, he reported, "Heaven knows I am glad to leave that," and his score was 125; at 3 P.M. in an quiescent period, he felt "tired" and said, perspiring, "I don't want to do any more," and his score w r as 111 ; at 4 P. M. he reported head- ache, while his stomach was in perfect quiescence and he scored 120. After the meal at 7 P. M., the subject felt much refreshed and reported, "Much easier to work now. I feel I can do ten times better." But his achievement in mental work was low, 123. Special fatigue was never reported during the contraction periods when mental efficiency was greatest. Fig. 22. shows a rapid fall in mental efficiency and the appearance of feelings of fatigue immediately following the contraction periods. The fact that the feelings of fatigue are not responsible for the effectiveness of work, is indicated by the low performance following the din- ner. The evidence indicates that the hunger contraction goes hand in hand with maximal performance. IN ITS RELATION TO ACTIVITY 47 TABLE V. Thorndike Intelligence Examination May 15, Subject C. Time Hunger Correcte'd Time Form started state Score seore taken A 10:05 A.M. Quiescent 123 123 30 min. B 10:38 " " " 123 +4 127 30 F 11:12 " " " 125 125 30 C 11:45 " " M 129 -1 128 29 G 12:21 P.M. " 129 +2.5 131.5 30 K 12:55 " " " 127 127 30 D 1:28 " " Contraction 142 -4 138 27' 40" M 2 :01 " " Quiescent 124 + 1 125 30 H 2:40 " " Contraction 126 -2 124 29' 30" L 3:13 " " Quiescent 110 + 1 111 29' 40" I 3:48 " " 128 +0.5 128.5 30 4 '21 " " 117 +3 120 30 E 4:57 " " Contraction 137 137 30 J 5:30 " " " 131 -0.5 130.5 30 N 8:05 " " After Supper 122 +1 123 30 Subjective feeling "Heaven knows I am glad to leave that." "Tired", per- spiring, "I don't want to do any more." "Headache." "Much easier to work now. I feel I can do ten times better." TtttA T C (JKDM HUIOEJ Contraction Periods .Subjective feeling u .# Heaven knows lam glad to leave that" ,. Tired" perspiring "I don't want to do any more" Headache" 9 Much easier now. I feel I can do ten times better Fig. 19. A diagram showing the curve of efficiency in the mental tests of Subject C, together with the hunger contraction periods and the subjective feeling reported. A star (*) indicates the contraction period and a double cross (#) the subjective feeling reported. * Thorndike, Edward L.: Equality in Difficulty of Alternative Intelligence Examinations. Psychological Review, 1921. 48 AN EXPERIMENTAL STUDY OF HUNGER Subject H took the same tests on June 9th, beginning- at 10 :35 A. M. He had had no food since the previous evening. The successive order of the tests was changed so as to bring the earlier half of the whole series later and vice versa, in order to compare with the records for C. In the order of H, M, L, I, O, E, J, B, F, C, G, K and D, thirteen tests were given up to 6 P. M. After dinner, at 7, form N was given, while the last test was June 9, Subject H. TABLE VI. Thorndike Intelligence Examination Time Hunger Corrected Time Form started state Score score taken H 10 :35 A.M. Quiescent 135 -2 132 30 min. M 11 :08 " " " 125 -(-1 126 30 L 11 :43 " " " 145 -1 144 30 I 12 :19 P. M, Contraction 151 +0.5 151.5 30 1 :23 " " " 136 +3 139 30 E 1 :55 " " M 140 140 30 J 2 :30 " " Quiescent 148 -0.5 147.5 28' 15" B 3 :12 " " < 144 +4 148 28 F 3 :39 " " * 146 146 29' 25" C 4 :10 " " Contraction 152 -1 151 25' 45" G 4 :38 " " Quiescent 126 +2.5 128.5 29' 13" K 5 :08 " " Contraction 147 147 28' 10" D 5 :37. " " " 148 -4 144 26' 20" N 7 :00 " " After Dinner 142 +1 141 29' 35" A 11 :13 ' Contraction 151 151 29 m of ts H T. I O H Contraction x x x- ! Periods Fig. 20. A diagram showing the correlation of the hunger rhythm with the efficiency of Subject H in the mental tests. A star (*) indicates the hunger contraction period. IN ITS RELATION TO ACTIVITY 49 tried at 11:13 before the subject retired. Table VI shows the hunger state, the scores, and the time taken. Half of the group were finished within the time-limit, the shortest of them all being 25 minutes 45 seconds. But no special credit was given for it. Expressions of the subjective feeling were not obtained in this case. Fig. 20 shows the correlation of the curves of the intelligence test scores of Subject H, and of the stomach activity which was drawn from the measurement of amplitude of each stomach activity on the graphic record. An examination of these curves reveal that four out of five contraction periods were ac- companied by highest test scores, 144, 151.5, 151, and 147; while the remaining one contraction period had a test score of 139, which is a little below the average, 142.5 (P.E. -- 6.43). Study of the curve shows a rapid rise in efficiency, with the onset of the contractions to a maximum at about the middle of the period. Accompanying the decrease in the intensity of the contractions to the quiescent period, is a similar decline in the efficiency of the mental work. The two curves, in fact, are nearly parallel. Following the 6 o'clock dinner, a period of quiescence was fol- lowed by a gradually increasing stomach activity which did not culminate in acute contraction when the experiment was dis- continued at 11 :30 P. M. The curve of mental achievement is a close parallel. In order to test further the correlation of the subjective feeling with the actual efficiency, form D was given to Subject C on June 9th, at 11 :55 P.M. when he said that he was "tired, having been busy until so late." The set E was given at 8:08 A.M. when he woke from sleep and felt "Very good." Scores were 142 and 147 respectively. Subject H repeated this experiment on June llth and took D at 11 :19 P. M., E at 7:35 A. M. He scored 145 in D and 148 in E. All of these tests were given during con- traction periods. Table VII shows the details. During the "tired" periods, the scores are slightly lower, but the time spent is less, that is, there appears a tendency to hurry the work with, probably, no loss of efficiency per unit of time. This finding is in harmony with the other studies of the influence of feelings of fatigue 1 " 2 . 1 Thorndike, Edward L. ; Educational Psychology, Vol. III. 2 Gates, Arthur I.; Diurnal Variations in Memory and Association. Variations in Effi- ciency during the Day together with Practice Effects, Sex Differences and Correlations. 50 AN EXPERIMENTAL STUDY OF HUNGER TABLE VII. Thorndike Intelligence Examination June 9, Subject C. Time Hunger Form started state Score D 11:55 P.M. Contraction 146 A.M. 147 June 11, Subject H. D 11:19 P.M. Contraction 149 -4 7:35 A.M. 148 Corrected Time Subjective score* taken feeling 142 24' 25" "Tired being busy until so late." 147 28' 30" ''Very good." 145 23 min. "Very tired from working hard a whole day." 148 30 "Feel fine." The amount of difference in achievement in the Thorndike tests between contraction and quiescent periods may be illus- trated in another way. The Thorndike Intelligence Examination tests were given to the medical school class to which the two Sub- jects C and H belonged. Form D was given at first as a trial and immediately after it, form E was taken. Fig. 21 shows a surface of frequency based upon the measurements of this class of eighty-two graduate medical students with form E. The average of the scores of the total class is 117.5, the median devi- ation (P.E.) being 8.81 and S.D. 11.77. Subject C's score in this class was 106. This was before the fifteen forms of tests were given. All of his scores in the tests taken successively later on, are plotted in a curve in Fig. 21. Subject H made scores 114 and 116 in forms D and E respectively, when he took it with his class. All of H's scores are on the dia- gram in Fig. 22. Fig. 23 shows diagramatically the relative posi- tion of the two subjects in their class. C's average is 126.3, while H's is 144.2. The curve for Subject C is the same as in Fig 21. H's curve was altered from the one following the suc- cessive order of tests, into one according to the order of tests that C took. This changed but little the general outline of H's curve. The variability of performance is so great, that the scores of the single individual range over half, or more than half, of the range of the whole class. Part of the individual variability is due to practice and to the inequality of the several forms of the tests, although correc- For the class Range 59 (83-142) S. D. 11.77 For Subject C 41 (106-147) 8.26 For Subject H 37.5 (114-151.6) 11.0 IN ITS RELATION TO ACTIVITY 51 tions for the latter were made. The learning curve is extremely irregular and Figs. 19 and 20 show that the variations are cor- related with conditions of the stomach, rather than with the de- gree of practice. That the shape of the curve was not caused wholly by the inequality of the tests is indicated by the fact that the IT-" "-"-"- /CO /3S J50 r no //s /so 12$ / Fig. 21. A diagram showing the surface of frequency based upon the test scores of the class, and the curve of the successive scores of Subject C. A star (*) indicates the scores achieved at the contrac- tion periods. A double cross ( ^ ) indicates the scores at the quiescent periods. 52 AN EXPERIMENTAL STUDY OF HUNGER order of tests for Subject H was the reversal of that for Sub- ject C. Their achievements varied similarly and seemed unques- tionably to parallel the degree of activity of the stomach. The two indication marks, a star (*) and a double cross (#) in Figs. 21, 22 and 23, prove that in all curves the test scores are high at the hunger contraction periods, and low at the quiescent periods. f* yf 10 15" JIQ /OS" //O ~ 11$ /20 JZ5~ /30 /35" JH-0 If-S ISO Fig. 22. A diagram showing the surface of frequency based upon the test scores of the class, and the curve of the successive scores of Subject H. A star (*) indicates the scores gained at the contraction periods. A double cross ( # ) indicates the scores at the quiescent periods. IN ITS RELATION TO ACTIVITY 53 The foregoing experiment proved that hunger augments mental efficiency. The effect on fatigue of this continuous mental work appeared in the fact that in the case of Subject C, the hunger con- traction periods were much depressed and did not take normal frequency nor vigor, though this was not so marked in the case of H. The subjective feeling of fatigue correlated very closely with the quiescent periods and the low efficiency. 85 /SO Fig. 23. A diagram showing the relative position of the scores of two Subjects, C and H, and their averages in the surface of frequency in relation to the class average. 54 AN EXPERIMENTAL STUDY OF HUNGER CHAPTER IX. THE EFFECTS OF VARIOUS STIMULI UPON THE HUNGER RHYTHM. 1. THE EFFECT OF MECHANICAL STIMULATION. During the night experiment of April 24th the experimenter twice blew the stomach balloon to see if there had been any wreckage, since after strong contraction periods, the respiration pres- sure rhythm became so low that it extended beyond the limit of the smoked paper. Each time when the tube to the manometer was disconnected for a few minutes and the balloon was distended, there appeared on the record a few stomach contractions, while the stomach was quiescent otherwise. Curiously enough, the bodily movements appeared simultaneously with these contrac- tions. Further study of this phenomenon was taken up on June 9th. At 4:15 A.M., while Subject C was asleep, the stomach balloon was disconnected from the manometer, and w r as blown up to such an extent as to bring the marker one inch higher in posi- tion on the smoked paper. This was done five minutes after a long contraction period, which had lasted twenty minutes. This distention of the balloon was immediately followed by a long contraction period which lasted 45 minutes, the contractions numbering 43. The same stimulus was given at 5:15, ten min- utes after this long contraction period. It started one large con- traction and a large bodily movement. (See Fig. 24.) At 7:15. ten minutes after a strong contraction period, blowing the bal- loon produced a one-inch contraction, and a few T wrigglings of the body. Ten minutes later, at 7 :26, in the midst of a quiescent period, there followed, a few minutes after the stimulus was given, one contraction and a body movement. On June 10th this experiment was repeated with Subject H. After a strong*, one-hour contraction period, a state of quies- cence set in, and lasted for 50 minutes. At 6:20, the stimulus of distending the balloon was given. As soon as the apparatus started to mark, it showed a strong contraction period, which lasted for 30 minutes ending with a tetanus. IN ITS RELATION TO ACTIVITY Fig. 24. A and B. Effects of various stimuli. Mechanical stimulus of blowing balloon. 55 A. B. 56 AN EXPERIMENTAL STUDY OF HUNGER Subject H was once more tested on the following night, June llth. There was a contraction period up to 5:20 A.M. which was followed by a tetanus, and a long quiescent period. After the stomach was perfectly quiet for 40 minutes, the stimulus was introduced, at 6:05. This did not bring about any result until five minutes later when there came a gradual start of a con- traction period. At 7 :20, at the end of a vigorous contraction state, another blowing of the balloon was introduced. Three minutes after there was a contraction and a few bodily move- ments and a few minutes later the subject awoke. 1"he above results show that, out of seven experiments, two immediately started contraction periods, lasting 45 and 30 min- utes respectively ; one started a group of contractions five min- utes after the stimulus, and four gave a few contractions and bodily movements. These mechanical stimuli seemed to arouse local reflexes of the stomach, which may be controlled by the plexuses of Auerbach and Meissner. About the same time that the present writer had found these results, Carlson* published his results wherein he concluded that mechanical or electric stimu- lation of the lung, the gall bladder, the heart, the urinary bladder, and the entire gastro-intestinal tract induces skeletal reflexes both in decerebrated and in purely spinal preparations. The bodily movements that occurred simultaneously with the stom- ach contraction seemed to prove that the afferent nerve fibres of the viscera make reflex connections with the skeletal motor system, though they may have long latent periods and rapid fatigue, which indicate a complex synaptic system, either in the spinal cord or in the visceral afferent paths. Carlson assumes that these visceral skeletal reflexes, at least as regards the extremities, are essentially of the defensive or es- cape type. It suffices, however, to state that the present experi- ment proved that the mechanical stimulation produced the stom- ach contractions, as well as bodily movements in man. 2. THE EFFECT OF DRUGS. Papaverin, an opium alkaloid (C 12 H 21 NO 4 ), has been estab- lished, especially on the continent of Europe, as having the ef- fect of paralyzing smooth muscles, such as those of the stomach. Dr. D. Macht, of Johns Hopkins University, has extracted the * Carlson, A. J.; American Journal of Physiology. Vol. 55, P. 384, 1921. IN ITS RELATION TO ACTIVITY 57 essence of this drug and produced, by combining it with other solutions, such as alcohol and wine, a little more tasteful drug, called benzyl-benzoate. These drugs are used to stop smooth muscle contractions of the stomach or intestines, in cases of hemorrhage or vomiting. In the present study these two drugs were used to determine (1) how they affected the hunger contractions during sleep, and (2) whether relaxation of the stomach muscles influenced the gross bodily movements. On April 13th, at 10:30 P. M., Subject B took 4 cc. of benzyl- benzoate by way of the mouth, together with y^ of a glass of water to clean the mouth. The subject went to bed immediately, and the record was taken, both of the stomach activity and the bodily movement, until he awoke at 8 A. M. next morning. There was a long tonus period, 10:30 P. M. to 1 :30 A. M., lasting nearly 3 hours, during which tonus waves were large and distinct. The contraction periods of 1 :30 A. M. to 2 A. M. and 3:15 A. M. to 3:30 A.M. were of small amplitude. This experiment showed that (1) the drug gave a primary stimulating effect, so that the tonus waves were of larger amplitude ; (2) that the stomach had a longer period of quiescent and tonus states ; (3) that the stomach contractions of the early part of the night were of smaller amplitude than usual. Lest other components of the drug had some stimulating effect, the essence of the original Papaverin was tried on the same subject, on April 20th. From 10:30 P.M. to 2 A.M., the stomach was very quiet. The contraction period from 2 A. M. to 2 :30 A. M. was of very small amplitude, and until 5 :10 A. M. the stomach was practically atonic. Three contraction periods, 5 :30 A. M. 5 :45, 6 :30 7 ; and 7 7 :30, became gradually larger, and the final one was of the amplitude of 4.5 inches. This result can be interpreted to mean that the drug had the effect of keeping the stomach muscles relaxed until 5 :10, and after that, vigorous con- tractions were resumed gradually. The bodily movements fol- lowed quite the same distribution ; when the stomach was atonic no body movement could be seen. There was no way of knowing just when the drug had been absorbed, or had begun to have effect. It would be of value to introduce this drug as a subcu- taneous injection at the height of each hunger contraction, and determine how long it will have effect in controlling the muscular movements of the stomach. 58 AN EXPERIMENTAL STUDY OF HUNGER 3. THE EFFECT OF CONSCIOUS EFFORT, THOUGHT; SIGHT, SMELL AND TASTE OF FOOD. Oh June 9th, at 6 P. M., when Subject H had contractions, the experimenter asked him to try to stop them. In spite of his effort, large contractions continued. Again he was asked to try to start 'contractions bv his effort. The request was made in the quiescent state, but the subject, of course, did not know it. His conscious effort made no difference on the record. The same request was asked of Subject C on June 10th, at 7 :45 A. M., before breakfast. This brought no contraction change, not even respiration change. We can be quite sure, from these re- sults and from other considerations, that the stomach contrac- tions, or quiescence are quite independent of conscious control. A few minutes before 6 P. M., on June 5th, Subject C was asked to shut his eyes and think of delicious dishes a dish of hot roast beef with mashed potatoes and green peas, salad of fresh lettuce and tomatoes, and hot mince pie all of which the subject especially liked. This thinking was done while the stom- ach was quiescent. The record showed no effect. On June 9th Subject H was asked to think of a dish of sweet, juicy and delicious cherries. This thinking was done while the stomach was in contraction, and the record showed no effect. A dish of cherries was then brought in, which the subject was allowed to observe and smell as much as he liked. No change appeared. However, as soon as the food particle was placed on his tongue, salivary secretion gushed out, which, together with some of the juice of the food, was swallowed. The contraction stopped at once. (See Fig. 25.) In the morning of June 10th, at 7:45, when Subject C awoke from his dream-experiment, the experimenter asked him to think of a dish of sliced oranges for breakfast. This started no contraction, but rather brought down the tonus state into still lower stomach pressure condition. After 5 minutes a dish of juicy sliced oranges was brought in, and the subject looked at them and smelled them. The stomach started no contraction from these stimuli. It is clear so far (1) that conscious effort to start or to stop stomach contractions is of no effect ; (2) that the thought, sight or smell of food has no direct influence to start or to stop the stomach contraction ; and (3) that food particles, or juice, or even some amount of saliva swallowed, stops the stomach con- traction. IN ITS RELATION TO ACTIVITY 59 Fig. 25. (A) Thought of delicious food, hot beefsteak with mashed potatoes and green peas, fresh green salad with tomato slices, and hot mince pie with cheese, did not stop contraction. (B) Actual taste of food stopped contraction and swallowing the juice through the esophagus is marked as if being contraction. 4. THE EFFECT OF NAUSEA FROM ROTATION. Dr. Knight Dunlap has devised a rotating chair on which a subject sits and can be rotated at the desired speed to the right or left turn by adjusting the switch. On May 22nd, Subject C, who had had no luncheon, sat on this chair. The experimenter waited until the tonus state appeared on the record. Ten minutes' ro- tation was given at 2:30 P.M. It did not bring nausea, but brought the tonus state of the stomach into perfect quiescence. Thirty minutes later another rotation, 20 minutes long, was given. The subject felt dizzy and nauseated. He looked pale and perspiration was seen on his forehead. The condition of the stomach was absolutely atonic. In spite of the fact that usually this subject had two strong contraction periods in the late afternoon, between 4 and 5, there appeared no hunger period, not even the slightest tonus, up to 5 :30. Rotation seemed to liave had enough effect to depress the tonus, and the contraction of the stomach. The physiological phenomena of nausea, the general emotional state of disagreeableness, as well as the un- familiar situation of sitting in an electric chair, may each have contributed to this general depression of the stomach activity. 60 AN EXPERIMENTAL STUDY OF HUNGER 5. THE EFFECT OF ELECTRIC SHOCKS. On May 21st Subject H came to the laboratory without lunch. He was provided with a wire ring on a finger of the left hand. and a metal plate on the right arm, which w r ere parts of an electric circuit closed by a switch, which was controlled by the experimenter. The experimenter waited until a large tonus appeared before pressing the button of the switch. In the middle of the upgoing tonus rhythm, electric shocks were given. The tonus waves, however, pursued the normal course without being checked by the shock. This was repeated at another tonus period, with the same result. The experimenter expected to try at the contraction periods, but the subject had no contraction period that day. On the following day, Subject C went through the same experiment. The result was similar except that twice, out of ten shocks, tonus waves dropped to the level immediately after the stimulus. In both cases the subjects felt uncomfortable because of re- ceiving shocks, and they said, "I don't like that !" There was no contraction period in either case. Probably it was this emo- tional state of general discomfort and fear that influenced and inhibited the occurrence of the contractions. These external electric stimuli seemed to affect the autonomic nervous system, and produce general emotional states, which inhibit the muscular activity of the stomach. 6. THE EFFECT OF PROLONGED WORK. On April 3rd, at 9 A. M., Subject C began to copy from an Italian book, which he did not understand. He had had no food since the previous evening. He typed with an Underwood ma- chine while the apparatus was recording his hunger states. Up to 1 :20 one continuous state of quiescence persisted. After a few minutes of high waves, quiescence followed and lasted for 2 more hours. At 3 :30 eleven contractions of 2.2 inches were seen. At 5 P. M. the work was stopped and the subject was allowed to go to sleep. As soon as he fell asleep, hunger contractions of 3^2 inches in height appeared. From 5 to 6 P. M. there was a continuous series of strong contractions, which numbered 52 in all. In the normal records, this individual had contraction periods most frequently at 11 o'clock and 1, 2, 4 and 5 o'clock, while in IN ITS RELATION TO ACTIVITY 61 the work experiment, all the forenoon and afternoon contraction periods were eliminated. The subject himself said that he did not feel hungry at all during the work. Prolonged work, when it involved feelings of fatigue and lack of interest, perhaps through correlation with an emotional condition, tended to inhibit the hunger contractions. 7. THE EFFECT OF READING EXCITING STORIES. 1. An Interesting Story. On May 9th Subject H swallowed the stomach balloon, and then read "Moon Calf" from 9:30 to 6 P. M. He was alone in an experimental room, and was allowed to use the chair or the couch. He read the story with great absorption, especially the part of the book from the climax on to the end. The record, registered in the next room, showed three contrac- tion periods, which were much shorter and of less amplitude than the normal ones. 2. Stories of Fear and Horror. Edgar A. Poe's stories, "Fall of the House of Usher," "Murders in the Rue Morgue," "The Premature Burial," and "The Pit and the Pendulum" were se- lected for arousing the emotion of fear and horror in the sub- ject. From 1 :45 to 6 P. M. on June 5th Subject C read these stories. In spite of the fact that he had had nothing to eat since morning, the stomach showed no contraction until 4 :30, when very weak contraction waves started. On the other hand, deep breathing, which habitually occurred once every t\vo or three minutes, in this individual, was so much deeper that, on the record, it measured twice the amplitude of the usual ones. 3. Sad Stories. On June 9th, at 9 :50 A. M., the experiment was started with Subject C, who had had nothing to eat since the previous evening at supper. The selected stories were "Vanka," by Turgenief, "Hide and Seek," by Sologub. and "The Death of Nell" from Dickens' "Old Curiosity Shop." The record showed that there \vas general depression of the stomach ac- tivities. No contraction period appeared in the three-hour ex- periment. Thus far the results showed that certain types of reading brought about diffused, non-discriminable, and general emo- tional states, which tended to inhibit the full swing of the automatic movements of the stomach. 62 AN EXPERIMENTAL STUDY OF HUNGER CHAPTER X. . CONCLUSIONS. The present experimental study brought to light a certain number of facts that show the extent to which hunger plays its role as a dynamic force in the activities of life. The primary cause of the physiological and psychological phenom- enon of hunger is ascribed to a certain muscular contraction of the stomach. The hunger contractions of the stomach occur from 3 to 4 hours after a meal and recur at intervals as long as the stomach is empty. The start of the hunger contractions is controlled by the intrinsic nerves and is independent of the extrinsic nerves which have only regulatory effects. Thus the stomach is a self-starting organ and yet has intimate connection with other vital organs and glands, through the autonomic nervous system which maintains the general tone of the organic background of emotional and perhaps intellectual life. The effect of the gastric hunger contractions upon other physiolog- ical conditions was investigated as reported in Chapter II. Changes in respiration, vasomotor flow, and salivary secretion were studied in relation to the hunger contraction rhythm. Especially close cor- relation was found in the case of the salivary flow, which is one of the most immediate accessory phenomena of the hunger contractions. That the sensation of hunger occurs synchronously with the hunger contraction of the stomach was assured in the present experiment with four subjects, men and women, normal and clinical. This fact may be interpreted as -showing that the stimulus from the gastric organ affects the cortical integration centers in some way so as to set up impulses toward the co-ordinated action of securing food. The stomach contractions not only arouse the sensation of hunger but prepare the whole body for activity, even during unconscious states. The experiments on bodily movements of men, infants, and rats, showed that bodily movements occur simultaneously with the hunger contractions, while in the quiescent periods very few bodily movements occur. This was especially marked when the subject was asleep. In the cases of the infants and rats the periodical recurrence of bodily movements was strikingly regular. IN ITS RELATION TO ACTIVITY 63 In sleep we do not know to what extent the visceral stimuli of the hunger contractions affect the central nervous system. The states of dreaming and non-dreaming, however, seem to indicate something of the mental status of a sleeping man. The investigation of the correlation of the hunger contraction periods with the dreaming periods revealed it to he positive. Though we are sure that there are also other factors that control the occurrence and nature of dreams, the present results warrant the statement that men dream more at the hunger contraction periods than during quiescence. The augmentation of motor activity was tested by means of a hand-dynamomoter which was found to be less subject to the effects of practice than other familiar motor tests. The results showed that at the hunger contraction periods the power of grip is greater than at the quiescent or after dinner periods. The average of all con- traction period scores compared with those quiescent and after-dinner- period scores is 88.98 kg. (P.E. A == .55) vs. 86.64 (P.E. A == .49) and 81.84 (P.E. A - .40) for Subject C and 90.91 kg. (P.E. A : .22) vs. 87.11 (P.E. = .28) and 86.42 (P.E. = .40) for Sub- A. A ject H. A further experiment to measure the effect of the hunger con- tractions in its relation with mental activity, Chapter VIII, produced the following facts: using fifteen forms of the Thorndike Intelligence Examination, Part I, a high correlation between the hunger con- traction periods and test scores was found. These tests are relatively free from the effect of practice, but vary according to the presence or absence of the hunger contractions. It seems safe, therefore, to say that hunger augments efficiency in mental work. Thus far the experiments were directed toward measuring the effect of hunger upon physiological conditions, the sensation of hunger, bodily movements during waking and sleeping states, motor activity and mental activity. The next group of experiments had the purpose of investigating the effects of mechanical, chemical, conscious, and emotional stimuli upon the hunger states. The mechanical stimulation of distending the balloon in the stomach produced a group of contractions accompanied by bodily move- ments of the sleeping man. The chemical action of drugs, benzyl- benzoate and papaverin. which have relaxing and tonus-lowering influence on the smooth muscle structures, depressed the periodicity and vigor of the hunger contractions. Less frequent and less vigorous appearance of the hunger contractions resulted in fewer and weaker movements of the body of the sleeping man. 64 AN EXPERIMENTAL STUDY OF HUNGER The conscious effort to start or to stop the contractions of the stomach had no influence in controlling the hunger rhythm. The thought, sight, smell, and taste of appetizing food failed to have any observable affect upon the gastric hunger states. These facts prove that the hunger rhythm is not a matter that can be controlled directly by the conscious center of "will" or motive. The nervous system that regulates the tonus and the rhythm of hunger contraction is very sensitive to emotional stimuli. The effect of nausea from rotation, electric shocks, and fatigue from pro- longed work, showed that as the consequence, the hunger rhythm is distorted and the contractions are inhibited. Reading exciting stories brought about emotional situations which, irrespective of whether they were of interest, fear, horror, or sorrow, had inhibitory effect upon the hunger rhythm. Emotional stimuli, therefore, affect the autonomic (especially the sympathetic) nervous system which has an inhibitory influence upon the visceral function of the stomach. From the preceding conclusions of the present experiment it is evident that hunger is not merely a local function of a local organ. It involves the whole organism, and it stimulates the motor and mental apparatus so as to bring the organism into a state of readiness to secure food. Biological consideration of the hunger behavior of lower animals, permits us to say that the state of tension of the whole organism prepares it for the strife and struggle against the enemies which lie between it and its food. Hunger is ontogenetically and phylogenetically one of the oldest phenomena, appearing in the first day of the infant life and in the first days of the unicellular ancestor. The hunger mechanism is one of the most primitive organs, in the sense that its activities are carried on partly by automatic activities of the organ without extrinsic nervous control, and partly by the sympathetic nervous system, which is said to be "a direct survival of that diffused type of nervous system which alone is found in the lowest animals which possess nerves at all, such as some jelly fishes and worms. It serves to supplement the non- nervous protoplasmic activities of the different tissues which co-operate in the performance of the work of the several organs."* Yet this most primitive mass of tissues and nerves forms the vital organ for the survival of its owner, and gives moreover a characteristic organic background to the entire conscious life. What Herrick* expressed in connection with emotions in general is found here to be applicable * Herrick, C. Judson; An Introduction to Neurology. 1918, P. 252, 290. IN ITS RELATION TO ACTIVITY 65 to hunger also. "In normal man the mechanisms may function with a minimum of cortical control, giving the general tone of well-being or malaise, or they may be tied up with the most complex cortical processes, thus entering into the fabric of the higher sentiments and affections and becoming important factors in shaping human conduct." Thus hunger determines not only the inner conditions of man, but works as a driving force for the projection apparatus, arms and legs, etc., to act upon the outer world. When viewed sociologically we are amazed at the fact that the most complicated events may be traced back to the simple and normal craving for food. In the economic world, food stuff is the barometer for the rise and fall of the cost of living. The fact that hunger can not be voluntarily controlled, does not mean, however, that there is no way of guiding and educating this fundamental force of human life. The laws of adaptation estab- lished in the studies of conditioned reflexes, modified reactions to stimuli, substitution, and sublimation find their application here also. Especially in early childhood, educators find opportunities to direct the habit formation of infants according to the law of hunger and its periodicity, the law of sleep and activity periods in relation to hunger, instead of according to tradition and hap- hazard ways. For the problems of work periods in school and other occupations, if the leaders keep in mind the same funda- mental laws, they can utilize and co-operate with these natural tendencies for activity and non-activity periods. Without the realization of this biological readiness of the organism in hunger which has been hitherto called the instinct of food-seeking, short- sighted guidance and suppression may give rise to riots, revolu- tions, and international wars. The degree to which we are able to control the dynamic force of life depends upon the extent of our knowledge of the force. VITA The author, Tomi Wada, was born in Toyamaken, Japan, on July 1st, 1896. She received her early educa- tion in Niigata, Osaka, and Kobe, graduating from Kobe Girls' High School in 1914. She continued her studies in the English Department of Japan Women's University in Tokyo, receiving the diploma in 1917. She was a student at Teachers' College, Columbia University, from February, 1918, to February, 1921, receiving the degree of Master of Arts in June, 1920. She was granted the Dean's Scholarship from Septem- ber, 1918, and the Graduate Scholarship from Septem- ber, 1920, .to February, 1921. During the summer of 1920 and from February, 1921, to February, 1922, she was a laboratory student at the Johns Hopkins Hospital. In the summer of 1922, she visited psychological laboratories in Europe. She was a student, at Columbia University from February to June, 1922. OCT 241975 14 DAY USE RETURN TO DESK FROM WHICH BORROWED BIOLOGY LIBRARY TEL. NO. 642-2532 This book is due on the last date stamped below, or on the date to which renewed. Renewed books are subject to immediate recall. INTERL1BRARYLOAN JAN 2 1993 LD2lA-6m~l,'75 (S3364SlO)476-A-32 General Library University of California