Lecture Viii

PHYSIOLOGICAL ACTION AND THE TEACHING OF INSTINCT: EXPERIENCES OF THE PHYSICIAN

It would be desirable, in the interests of medicine, that the methods described in these lectures should be employed in experimental investigations into the pathology and therapeutics of the digestive canal on the lines laid down--The fact that the beginning of the secretory work in the stomach depends upon a psychic effect harmonises with the experiences of every-day life, namely, that food should be eaten with attention and relish--To restore the appetite has from all ages been the endeavour of the physician--The indifference of the present-day physician towards appetite--Probable causes of this--Curative remedies based upon a restoration of appetite--The therapeutic effects of bitters depend upon the excitation of appetite--The usages of the mid-day meal are in agreement with physiological requirements--Physiological reasons for certain instinctive customs and empirical regulations--Importance of an acid reaction of the food--Dietetics of fat and its therapeutic application--The peculiar position of milk among food-stuffs is based on physiological reasons--Explanation of the curative effects of sodium bicarbonate and sodium chloride--The causes of individual differences in the work of the digestive glands--Participation of the inhibitory nerves of secretion in the production of pathological effects.

GENTLEMEN,--To-day we shall endeavour to bring the previously communicated results of our laboratory investigations into reconciliation with the customs observed in the ingestion of food, and with the regulations prescribed by the physician in disorders of the digestive apparatus. To bring our knowledge to full fruition, and so secure for it the most useful application, the same methods should be applied from the same standpoint to the experimental investigation of the pathology and therapeutics of the alimentary canal. Nor should we be likely to encounter insuperable difficulties. Thanks to the advances of bacteriology, many of the pathological processes can now be experimentally produced in the laboratory. Moreover, we would, in a sense, have to deal with external ailments, since our present methods enable us to obtain access to any desired part of the inner surface of the digestive canal. In such pathological animals the functional diseases of the apparatus could be studied in a precise and detailed manner; that is to say, the alterations of secretory activity, the properties of the fluids, and the conditions under which they appear could be examined. On such animals therapeutic remedies could also be tested, the whole process of healing and the final result experimentally observed, while the conditions of secretory activity during every phase of the healing process could be investigated. It can hardly be doubted that scientific, that is to say ideal, medicine, can only take its proper position as a science when, in addition to an Experimental Physiology and Pathology, there has also been built up an Experimental Therapeutics. A proof that this is possible is furnished by the recent vigorous strides made by the science of bacteriology.

I have already described one of such pathological therapeutic experiments; namely, on the dog whose vagi nerves were divided in the neck. Other similar cases I can also call to mind. Our dog with the two stomachs suffered at one time from a slight and transitory gastric catarrh. It was then very interesting to observe that the pathological process (which we were usually able to wholly guard against) spread from the large to the small stomach. It manifested itself here in an almost continuous slimy secretion of very slight acidity, but of strong digestive power. At the beginning of the ailment, indeed before it became fully established, the psychic stimulation was remarkably effective (that is to say, still furnished juice in appropriate quantity), while local excitants almost completely failed. One may conceive that the deeper layers of the mucous membrane with the gastric glands were still healthy, and thus easily thrown into activity by central impulses, whilst the surface of the membrane with the end apparatus of the centripetal nerves was already distinctly damaged. I mention these, which I may call impressions rather than precise observations, because I wish to point out what a fruitful field awaits the investigator who wishes to study, with the aid of our present methods, the pathological conditions of the digestive organs and their treatment. Such an investigation is all the more desirable because clinical study of the same subject (notwithstanding the zeal devoted to it during the last ten years and the results derived therefrom) has to contend with serious difficulties. We must not forget that the sound or stomach-tube, the chief clinical instrument, is more uncomfortable than the ordinary form of gastric fistula which was previously practised on animals, and yet the physiology of the stomach, even with the aid of the latter, made no material progress for many long years. Nor is this difficult to understand. The investigator obtained through the fistula a mixture of substances from which it was difficult, or even at times impossible, to decide anything.

Hence the exact scientific study of therapeutic questions in this region still belongs to the future. But this does not exclude the probability that the newer acquirements of physiology may fruitfully influence the work of the physician. But physiology naturally can make no pretence to guide the field of medicine, since the knowledge at its disposal is incomplete and is much more restricted than that of the broad world of clinical reality. As a recompense for this, however, physiological knowledge is often able to explain the causation of an illness and the meaning of empirical curative methods. To employ a remedy the mode of action of which is not clear is quite a different thing from knowing precisely what we are doing. In the latter case the treatment of the diseased organ will be more effective because it will be better adapted to the special needs of the case. It is thus that medicine, being daily enriched by new physiological facts, will at length grow into what it ideally must become; namely, the art of repairing the damaged machinery of the human body, based upon exact knowledge, or, in other words, applied physiology.

We may now return to our subject. If it be at all admitted that human instinct is the outcome of an every-day experience, which has led to the unconscious adoption of the most favourable conditions for life, it is particularly so with regard to the phenomena of digestion. The expression that physiology merely confirms the precepts of instinct is justified here more than anywhere else. It appears to me also that, in relation to the foregoing facts, instinct has often made out a brilliant case when brought before the tribunal of physiology. Perhaps the old and empirical requirement, that food should be eaten with interest and enjoyment, is the most imperatively emphasised and strengthened of all. In every land the act of eating is connected with certain customs designed to distract from the business of daily life. A suitable time of day is chosen, a company of relatives, acquaintances, or comrades assemble. Certain preparations are carried out (in England a change of raiment is usually effected, and often a blessing is asked upon the meal by the oldest of the family). In the case of the well-to-do a special room for meals is set apart, musical and other guests are invited to while away the time at meals--in a word, everything is directed to take away the thoughts from the cares of daily life, and to concentrate them on the repast. From this point of view it is also plain why heated discussions and serious readings are held to be unsuitable during meal-times. Probably this also explains the use of alcoholic beverages at meals, for alcohol, even in the lighter phases of its action, induces a mild narcosis, which contributes towards distraction from the pressing burden of the daily work. Naturally this highly developed hygiene of eating is only found in the intelligent and well-to-do classes, first, because here the mental activity is more strained and the various questions of life more burning; and secondly, because here also the food is served in greater quantity than is required for the wants of the organism. In the case of the poorer classes, where mental activity is less highly developed, the greater amount of muscular activity and the constant lack of more than sufficient nourishment insure a strong and lively desire for food in a normal manner, without recourse to any special regulations or customs. The same conditions explain why the preparation of food is so choice in the case of the upper classes and so simple in that of the lower. Further, all the accessories of the meal, which are foretastes of the actual repast, are obviously designed to awaken the curiosity and interest, and to augment the desire for food. How often do we see that a person who begins his customary meal with indifference afterwards enjoys it with obvious pleasure when his taste has been awakened by something piquant or, as we say, appetising. It was here only necessary to give an impulse to the organs of taste, that is, to excite them, in order that their activity might be later maintained by less powerful excitants, for a person who feels hungry such extra inducements are, of course, not necessary. The quelling of hunger in his case affords of itself sufficient enjoyment. It is not, therefore, without reason that it is often said that “Hunger is the best sauce.” This dictum, however, is only right up to a certain point, for some degree of appetising taste is desired by everybody, even by animals. Thus, a dog which has not fasted for more than some hours will not eat everything with equal pleasure which dogs usually eat, but will seek out the food which it relishes best. Hence the presence of a certain kind of spice is a general requirement, although naturally individual tastes differ.

This short discussion as to how different people behave with regard to the act of eating is of itself testimony that care should ever be taken to keep alive the attention and interest for food and to promote enjoyment of the repast--that is to say, that care should be taken of the appetite. Every one knows that a normal, useful food is a food eaten with appetite, with perceptible enjoyment. Every other form of eating, eating to order or from conviction, soon becomes worse than useless, and the instinct strives against it. One of the most frequent requests addressed to the physician is to restore the appetite. Medical men of all times and of every land have held it to be a pressing duty, after overcoming the fundamental illnesses of their patients, to pay special attention to the restoration of the appetite. I believe that in this they are not only animated by an endeavour to free their patients from troublesome symptoms, but also by the conviction that the return of appetite of itself will favour the restitution of normal digestive conditions. It may be said that to the same extent to which the patient wishes back his appetite the physician has effectively employed measures to restore it. Hence we have not a few remedies which are specially named “gastric tonics,” and whose action is to promote appetite. Unfortunately medical science has latterly deviated from this, the correct treatment of the appetite, and that which corresponds to the real conditions. If one reads current text-books on disorders of digestion, it is remarkable how little attention is paid to appetite as a symptom or to its special therapy. Only in a few of them is its importance indicated, and then merely in short, parenthetic phrases. On the other hand, one may meet statements in which the physician is recommended to adopt no special means for counteracting so unimportant a subjective symptom as a bad appetite! After what I have said and demonstrated to you in these lectures, one can only designate such views as gross misconceptions. If anywhere, it is precisely here that symptomatic treatment is essential. When the physician finds it necessary, in disorders of digestion, to promote secretory activity by different remedies, this object can most certainly and completely be achieved by endeavouring to restore the appetite. We have already seen that no other excitant of gastric secretion, so far as quantity and quality of the juice are concerned, can compare with the passionate craving for food.

To a certain degree we can understand--and this contributes to an explanation of matters--how medical science of our time has come to regard so lightly the loss of appetite as a special object for treatment. Now, however, the experimental method has penetrated more and more into medical science, with the result that many pathological factors and therapeutic agents are judged of according to whether they hold good in the laboratory or not--that is to say, they are valued only in so far as they can be verified by laboratory experiments. Naturally we do not doubt that a movement in this direction indicates a great advance, but even here, as with every undertaking of mankind, things do not proceed without mistakes and exaggerations. We must not consider an event to be a mere picture of the imagination because it is not realisable under given experimental conditions. We often do not know all the essential conditions for the production of the phenomenon in question, nor are we yet able to grasp the connection between all the separate functions of life as fully as may be desired. Thus in the clinical treatment and pathology of digestion assistance was sought for in the laboratory, but nothing was there met with which had a relation to appetite, and consequently this factor was overlooked in medical practice. As stated above, the psychic gastric juice obtained only cursory mention in physiology, and this not even by all authors; and when it was noticed it was related more as a curiosity. Great importance was, on the other hand, assigned to the mechanical stimulus, the efficiency of which, now that our knowledge is more complete, has been shown to be purely imaginary. Each of the contending factors has at length been assigned its proper place, and if clinical medicine maintains her worthy desire of following out the experimental investigation of her problems, she must in actual practice accord to appetite its old claim for consideration and treatment.

But notwithstanding the indifference of physicians to appetite in itself, many therapeutic measures are based on the promotion of it. And in this the truth of empiricism makes itself irresistibly felt. When the patient is enjoined to eat sparingly, or when he is restrained from eating at all till the physician expressly permits, or again, when he is (for instance, during convalescence) removed from his ordinary surroundings and sent to an establishment where the whole life, and particularly the eating, is regulated according to physiological needs--in all these cases the physician seeks to awaken appetite, and relies upon it as a factor in the cure. In the first case, where the food is prescribed in small portions, in addition to preventing the overfilling of a weak stomach, the oft-recurrence of appetite juice, which is so rich in quantity and so strong in digestive power, is of great importance. I ask you here to call to mind one of our experiments in which food was given in small portions to a dog, and thus led to a secretion of much stronger juice than if the whole ration had been eaten at once. This was an exact experimental reproduction of the customary treatment of a weak stomach. And such a regulation of diet is all the more necessary, since, in the commonest disorders of the stomach, only the surface layers of the mucous membrane are affected. It may, consequently, happen that the sensory surface of the stomach, which should take up the stimulus of the chemical excitant, is not able to fulfil its duty, and the period of chemical secretion, which ordinarily lasts for a long time, is for the most part disturbed, or even wholly absent. A strong psychic excitation, a keen feeling of appetite, may evoke the secretory impulse in the central nervous system and send it unhindered to the glands which lie in the deeper as yet unaffected layers of the mucous membrane.

An instance of this, taken from the pathological material of the laboratory, I have already related at the beginning of this lecture. It is obvious in these cases that the indication is to promote digestion by exciting a flow of appetite juice, and not to rely upon that excited by chemical stimuli. From this point of view the meaning of removing a patient, the subject of chronic weakness of the stomach, from his customary surroundings is also plain. Take, for instance, a mentally overstrained individual, or a responsible official; how often does it happen that he cannot for a moment distract his thoughts from his daily work. He eats without noticing it, or eats and carries on his work at the same time. This often happens, particularly in the case of people who live in the midst of the incessant turmoil of great cities. The systematic inattention to the act of eating prepares the way for digestive disturbances in the near future, with all their consequences. There is no appetite juice, no “igniting juice,” or, at most, very little. The secretory activity comes slowly into play; the food remains much longer in the digestive canal than is necessary, or passes, for want of sufficient digestive juices, into a state of decomposition which irritates the mucous membrane of the alimentary canal and brings it into a condition of disease. No medicinal treatment can help such a patient while he remains surrounded by his old conditions. The fundamental cause of his illness still continues in progress. There is only one course to pursue; namely, to take him completely away, to free him from his occupation, to interrupt the interminable train of thought, and to substitute for a time, as his only object in life, the care of his health, and a regard for what he eats. This is attained by sending the patient to travel, or by placing him in a hydropathic establishment. It is the duty of the physician to regulate not only the life of individual patients according to such rules, but also to have a care that in wider circles of the community a due conception of the importance of eating should be disseminated. This is particularly so with the Russian physician. It is precisely in the so-called intelligent classes of Russians that a proper conception of life generally is often found wanting, and where an absolutely unphysiological indifference towards eating often exists. More methodical nations, like the English, have made a species of cult of the art of eating. It is, of course, degrading to indulge excessively and exclusively in culinary enjoyments, but, on the other hand, a lofty contempt for eating is also reprehensible. As so often is the case, the best course here also lies between the two extremes.

With the establishment of mental effect upon the secretion of juice the influence of condiments enters upon a new phase. The conclusion had already been empirically arrived at that it was not alone sufficient for the food to be composed exclusively of nutrient substances, but that it should also be tasty. Now, however, we know why this is so. For this reason the physician, who has often to express an opinion upon the suitability of the dietaries of different persons, or even of whole communities, should constantly bear in mind the question of psychic secretion; that is to say, he should inquire after and learn how the food has been eaten, whether with or without enjoyment. But how often do the people who have charge of the commissariat pay attention solely to the nutritive value of the food, or place a higher value on everything else than taste? We must, further, in the interest of the public weal, direct attention especially to the feeding of children. If this or that inclination of the taste ultimately determines the relation of grown-up individuals towards food, a matter with which the commencing phase of digestion is closely linked, it would seem undesirable to habituate children solely to a nicety and uniformity of gustatory sensations. Such might effect their capabilities of adapting themselves to other conditions in after life.

The question of the therapeutic influence of the so-called bitters, it appears to me, bears the closest connection with that of appetite. After a long period of high repute these substances have been almost expelled from the list of pharmaceutic remedies. When tested in the laboratory, they were unable to justify their old and valued reputation; when directly introduced into the stomach, many of them were unable to produce a flow of gastric juice. Consequently, in the eyes of the clinician, they became greatly discredited, so that many were quite ready to discard their use altogether. Obviously, the simple conclusion was drawn that a weak digestion could only be assisted by a remedy which directly excites secretory activity. In this, however, it was forgotten that the conditions of the experiment possibly had not corresponded with the actual state of affairs. The whole question of the therapeutic importance of the bitters, however, acquires a different significance when we link it with another question, such, for instance, as how do bitters affect the appetite? It is the universal opinion of the earlier and later physicians that bitters increase the appetite, and if this be so everything is said. They are, in consequence, real secretory stimulants, since the appetite, as has many times been repeated in these lectures, is the strongest of all stimuli to the digestive glands. It is, however, not by any means strange that this had not previously been observed in the laboratory. The substances were either introduced directly into the stomachs of normal dogs or else injected into the circulation. But their action is chiefly bound up with their effect upon the gustatory nerves, and it was not, therefore, without some reason that this large group of remedies, consisting of substances of the most varied chemical composition, were grouped together mainly on account of a certain bitter taste common to them all. A person who suffers from digestive disturbance has, moreover, a blunted taste, a certain degree of gustatory indifference. The ordinary foods, which are agreeable to other people, and also to himself when in health, now appear tasteless. They not only arouse no desire for eating, but may even cause a feeling of dislike; there is no sense of taste, or at best a perverse one. It is necessary, therefore, that the gustatory apparatus should receive a strong stimulus in order to restore a normal sensation. As experience teaches, this object is most quickly attained by exciting sharp, unpleasant, gustatory impressions, which by contrast awaken the idea of pleasant ones. In either case there is no longer indifference, and this is the foundation upon which an appetite for this or that kind of food may be awakened, and here a general physiological law is illustrated. The light appears brighter after darkness, a sound louder after silence, the enjoyment of blithesome health more intense after illness, and so on. This explanation of the appetising effects of bitters proceeding from the mouth does not exclude the possibility of some such similar influence coming also from the stomach. As has been already stated in the fifth lecture, there is some reason for believing that certain impulses from the cavity of the stomach are likewise necessary for the excitation of appetite. It is possible that bitters not only act directly on the gustatory nerves in the mouth, but that they also act on the mucous membrane of the stomach in such a way that sensations are generated which contribute to the passionate craving for food. As a matter of fact, it has been confirmed by many clinicians that after the administration of bitters some such special sensations do arise in the stomach. The effect of these remedies consists, therefore, not merely in the generation of a simple reflex, but in the production of a certain psychic effect, which indirectly excites a physiological secretory activity. The same probably applies to other substances, such as condiments. In any case, whether our explanation corresponds to the actuality or not, the question of the therapeutic effect of bitters is settled in the affirmative the moment we acknowledge that these substances awaken appetite. The problem, therefore, of an experimental investigation of bitters consists in establishing the fact that they have an effect upon the appetite. The question is a difficult one, and has not hitherto been attempted in the laboratory. It is not sufficient to hand over clinical observations to the laboratory as experimental proofs. One must have, in addition, the assurance that the investigation has been correctly carried out; that is to say, that it dealt exactly with the point under consideration. It is interesting to observe that the connection between appetite and gastric juice is by many physicians, and in many text-books of medicine, exactly reversed. Thus it is represented that some medicinal remedy calls forth a secretion of gastric juice, and this, by its presence in the stomach, awakens an appetite. Here we have to deal with a false explanation of a true fact, and that because it was not recognised that a psychic effect could by any possibility be a powerful excitant of secretory nerves. The customs of the chief meal of the day also correspond with our physiological results. After this or that hors d’œuvre, perhaps also with a liqueur of brandy (especially customary in Russia), both of which are designed to awaken the appetite, the repast proper begins, and, in the majority of cases, with something hot, consisting mostly of meat broth (bouillon, different soups, and so on). After this comes the really nourishing food--meat of different kinds served in various ways, or, in the case of poorer people, stews made with vegetables, and therefore rich in carbohydrate material. This sequence of foods, from the standpoint of physiology, is quite rational. Meat broth, as we have already seen, is an important chemical excitant of gastric secretion. An attempt is therefore made in two ways to secure a free secretion of gastric juice to act on the chief food; first, in the excitement of the appetite juice by the hors d’œuvre, and secondly, in the promotion of the flow by the action of the meat broth. It is in this way that human instinct has made provisions for the digestion of the chief meal. A good meat broth can only be afforded by well-to-do people, and consequently with the poorer classes a less expensive, and, indeed, also a less effective, chemical excitant is used for awakening the early secretion. For example, kwas serves in this way with the Russian population, while in Germany, where the price of meat is high, different kinds of soups are used, consisting of water mixed with flour, bread, etc. It is further to be borne in mind that the quantity of the digestive juices in general stands in close connection with the content of water in the organism. This has been shown by the experiments of Dr. Walther for the pancreatic juice, and by my own for the gastric juice. If this sequence of foods, therefore, holds good for healthy people, it must be even more strictly adhered to in pathological conditions. Thus, when a person has no appetite, or only a weak one, he has no psychic juice or only very little; consequently, the meal must in every case be begun with a strong chemical excitant--for example, with a solution of the extractives of flesh. Otherwise solid foods, particularly if they do not consist of meat, would remain long in the stomach without any digestion whatever. It is, therefore, in every way desirable to prescribe meat juice, strong broth, or meat extract to people who have no appetite. The same applies also to forced feeding, for instance, of the insane. It is true that the method of introduction in this case necessarily secures the presence of a chemical excitant, since the food can only be introduced in a fluid form. In any case the addition of meat extract would be very useful. If one arranged the ordinary fluid foods in descending order, according to the influence of the chemical excitants, the following would be the series: first, the preparations of the flesh, such as meat juice and the like; secondly, milk; thirdly, water.

The usual termination of the repast is also, from the physiological standpoint, easy to be understood. The chief meal is generally ended with something sweet, and everybody knows that sweets are pleasant. The meaning of this is easy to guess. The repast, begun with pleasure, consequent on the pressing need for food, must also, notwithstanding the stilling of hunger, be terminated with an agreeable sensation. At the same time the digestive canal must not be burdened with work at this stage; it is only the gustatory nerves which should be agreeably excited. After thus dealing in general with the usual arrangement of our meals, we may now speak of some special points.

Above all comes the acid reaction of the food. It is apparent that acidity enjoys a special preference in the human taste. We use quite a number of acid substances. Thus, for example, one of the commonest seasoning substances is vinegar, which figures in a number of sauces and such like. Further, many kinds of wine have a somewhat acid taste. In Russia, kwas, especially in the acid form, is consumed in great quantities. Moreover, acid fruits and green vegetables are used as food, and they are either of themselves acid, or made so in the preparation. In medicine this instinct is likewise often made use of, and acid solutions, especially of hydrochloric and phosphoric acids, are prescribed in digestive disturbances. Finally, Nature itself constantly endeavours to prepare lactic acid in the stomach in addition to the hydrochloric acid. The former arises from the food introduced, and is consequently always present. These facts are all physiologically comprehensible when we know that an acid reaction is not only necessary for an efficient action of the peptic ferment, but is at the same time the strongest excitant of the pancreatic gland. It is even conceivable that in certain cases the whole digestion may depend upon the stimulating properties of acids, since the pancreatic juice exerts a ferment action upon all the constituents of the food. In this way acids may either assist digestion in the stomach where too little gastric juice is present, or bring about vicarious digestion by the pancreas where it is wholly absent. It is easy, therefore, to understand why the Russian peasant enjoys his kwas with bread. The enormous quantity of starch which he consumes, either as bread or porridge, demands a greater activity upon the part of the pancreatic gland, and this is directly brought about by the acid. Further, in certain affections of the stomach, associated with loss of appetite, we make use of acids, both from instinct as well as medical direction, the explanation being that they excite an increased activity of the pancreatic gland, and thus supplement the weak action of the stomach. It appears to me that a knowledge of the special relations of acids to the pancreas ought to be very useful in medicine, since it brings the gland--a digestive organ at once so powerful and so difficult of access--under the control of the physician. We could, for instance, intentionally discard digestion in the stomach, and thus transfer it to the bowel, by prescribing substances which do not excite the gastric glands. On the other hand, by lessening the acidity of the gastric juice we could reduce the activity of the pancreas, and these are matters which might be made use of in various special diseases, or even in some general disturbances of the digestive apparatus.

No less instructive is a comparison of the results of our experiments upon fat, with the demands of instinct and also with the precepts of dietetics and therapeutics. Everybody knows that fatty foods are heavy, that is, difficult of digestion, and in the case of weak stomachs they are usually avoided. We are now in a position to understand this physiologically. The existence of fat in large quantities in the chyme restrains in its own interest the further secretion of gastric juice, and thus impedes the digestion of proteid substances; consequently, a combination of fat and proteid-holding foods is particularly difficult to digest, and can only be borne by those who have good stomachs and keen appetites. The combination of bread and butter is less difficult, as might a priori be inferred from its wide employment. Bread requires for itself, especially when calculated per unit, but little gastric juice and but little acid, while the fat which excites the pancreatic gland insures a rich production of ferment both for itself and also for the starch and proteid of bread. Fat alone does not count by any means as a heavy food, as may be seen from the fact that large quantities of lard are consumed in certain districts of Russia with impunity. This also is comprehensible, since the inhibitory influence of the fat in this case does not prevent the digestion of any other food-stuff, and is conducive to the assimilation of the fat itself. There is no struggle in this case between the several food constituents, and therefore no one of them suffers. In harmony also with daily experience the physician, in cases of weakness of the stomach, totally excludes fatty food and recommends meat of a fat-free kind; for example, game, etc. In pathological cases, however, where an excessive activity of the gastric glands is manifested, fatty food, or fat as emulsion, is prescribed. And here medicine has empirically brought to its aid the restraining action of fat, which we have so strikingly seen in our experiments.

Amongst all the articles of human food, milk takes a special position, and this is unanimously recognised, both in daily experience and in the practice of medicine. By everybody milk is considered a light food, and is given in cases of weak digestion as well as in a whole series of severe illnesses; for example, in heart and kidney affections. The extreme importance of this substance, a food prepared by Nature itself, we can now well understand. There are three properties of milk which secure it an exceptional position. As we already know, in comparison with nitrogenous equivalents of other foods, the weakest gastric juice and the smallest quantity of pancreatic fluid are poured out on milk; consequently, the secretory activity requisite for its assimilation is much less than with any other food-stuff. In addition, milk possesses a further important property. Thus, when it is introduced unobserved into the stomach of an animal it causes a secretion both in the stomach and also one from the pancreas; consequently, it appears to be an independent chemical excitant of the digestive canal; and in this action it is remarkable that we perceive no essential difference in the effect when the milk is brought unnoticed into the stomach from that which occurs when it is given to the animal to lap. Although flesh is a better chemical excitant, it is by no means a matter of indifference how it gets into the stomach. It must, therefore, be accepted that milk excites not only a really effective, but at the same time a very economic, secretion, and also that the appetite is unable to stimulate this secretion into a more active or abundant flow. The secret of the relation of milk to the secretion of the digestive juices can, unfortunately, at present be submitted to no further analysis or investigation. We are at liberty, however, to suppose that the fat on the one hand is of importance for the inhibition of the gastric glands, and the alkalinity on the other for the restraint of the pancreas. Thus the gastric glands and the pancreas, notwithstanding the presence of excitants, are maintained by milk at a certain but not too high degree of activity, a matter which is in every way desirable in consideration of the easy digestibility of its constituents. Finally, the third characteristic which is observed to belong to milk, and which is probably only an expression of the first, consists in the following. When one administers to an animal equivalent quantities of nitrogen, in the one case as milk, in the other as bread, and afterwards estimates the hourly output of nitrogen in the urine, it results that the increase during the first seven to ten hours after the milk (compared with the excretion beforehand) amounts only to from 12 per cent to 15 per cent of the nitrogen taken in, while after bread it amounts to 50 per cent. If the hourly rate of absorption and the extent to which milk and bread are respectively used up be taken into consideration, it has to be admitted that these augmentations of urinary nitrogen which appear soon after feeding must be expressions of the functional activity of the digestive canal itself, and that this activity in the case of bread is three or four times greater than in the case of milk (Experiments of Prof. Rjasanzew); consequently, in the case of milk a much larger fraction of its nitrogen is free to be used up by the organism at large (irrespective of the organs of digestion) than in that of any other kind of food. In other words, the price which the organism pays for the nitrogen of milk, in the form of work on the part of its digestive apparatus, is much less than that for other foods. How admirably, therefore, the food prepared by Nature distinguishes itself when compared with all others!

The facts just related bring forward a new aspect from which the relative nutritive values of different foods may be judged. The older criteria must frankly make room for the new or else be displaced by them. Experiments upon the utilisation of food-stuffs, in which what remains undigested is determined as well as what is absorbed into the body fluids, cannot alone be trusted to solve the question in a satisfactory manner. Suppose, for instance, that in the digestion of a given food the alimentary canal has been given a certain work to perform; if it be in health the work will be accomplished in the best possible manner--that is to say, with complete abstraction of everything nutrient. You will thus learn how much nutrient material was contained in the food, but the question of its digestibility remains as obscure as before. In your experiment you do not know how great an effort it has cost the alimentary canal to extract all the nourishment from the food. Nor can artificial digestion experiments settle the question of digestibility, for experiments in which food is normally partaken of are quite different from those in the test-tube, where we have to deal with only one juice, and not with the interaction of different juices and different food constituents. That one must here, as a matter of fact, make a distinction is clear from the observation of Dr. Walther in our laboratory. Fibrin, which is regarded by all as the most easily digested proteid, proved, when compared with a nitrogen equivalent of milk, to be a much stronger excitant of the pancreas, although milk contains, in addition to nitrogenous substances, a good deal of other non-nitrogenous material. The digestibility and nutritive value of foods must obviously be decided by an estimation of the real work which they entail upon the digestive apparatus, both in regard to the quantity and quality of the juices poured out on a given amount of nutrient material. The energy used up in gland metabolism must be deducted from that of food taken in. The remainder will then indicate the value of the food to the organism; that is to say, will give the amount available for use by all the other organs exclusive of the digestive apparatus. From this point of view those materials must be taken as less nourishing and less digestible which are in large part used up to make good the expenditure entailed by their digestion on the part of the alimentary canal; that is to say, those food-stuffs are less useful whose nutritive value little more than covers the cost of their digestion; consequently, it is of great practical importance to compare from this aspect the same foods differently prepared--for example, boiled and roast meat, hard and soft boiled eggs, boiled and unboiled milk, etc.

A discussion of some further medical questions may here be taken up. The first concerns the therapeutic use of the neutral and alkaline salts of sodium. In clinical, pharmacological, and physiological text-books it is stated now, as ever, that these salts promote a flow of gastric juice. We may look in vain, however, for any experimental foundation to support this doctrine. The experiments brought forward cannot be regarded as conclusive. When Blondlot sprinkled sodium bicarbonate upon flesh, or Braun and Grützner introduced sodium chloride solutions directly into the blood, they began with methods either false in themselves or far removed from normal conditions. In this case, however, the gaps in the experiment were happily made good by the clinician, for the experiment appeared to be confirmatory of clinical experience. That sodium salts (the chloride and bicarbonate) are useful in disorders of the digestive apparatus there can be no doubt. How do they act, however? It appears to me that here, as in some other cases, medical science has fallen into error. When we know that an effect takes place it does not by any means imply that we know the mechanism by which it occurs; and although medicine is broad enough and comprehensive enough to make free use of empiricism in practice, yet it often thinks in narrow grooves when it turns to the explanation of facts. It frequently tries to explain complicated healing processes in the simplest way, on supposed physiological data. And this is true in the present case, which affords an example of prevalent medical reasoning; the alkalies work favourably in digestive disturbances--therefore they are succagogues. Naturally the stomach, under the influence of alkalies, sometimes begins to secrete a greater quantity of juice. This means, however, that it has recovered from a disordered state and has returned to normal conditions. Consequently, the effect is due to the fact of recovery, and not to a direct influence of the alkalies. This latter, however, must be specially proved. The assistance afforded by the alkalies to the organism might be capable of another explanation; for example, that which is ordinarily given. In this case, however, I venture to offer a reason for the effects of sodium chloride, and of the alkaline salts of sodium, which is exactly the opposite of that generally accepted. We were unable to convince ourselves of any succagogue influence on the part of these salts. Indeed, both on the stomach and pancreas they proved in our hands to have an inhibitory effect. In addition to the experiments which I previously brought forward concerning the relation of alkalies to gastric and pancreatic juice, I may relate the following observation. A dog which fortunately had survived the performance, one after the other, of a gastric fistula, a pancreatic fistula, and an œsophagotomy, received daily during the course of several weeks an addition of soda to its food. The animal enjoyed good health and had an excellent appetite. When the first sham feeding experiment was carried out, the relatively small effect of this otherwise very active juice-exciting procedure at once struck us. At the same time we observed that the pieces of flesh which fell from the upper end of the œsophagus, contrary to the ordinary rule, were hardly at all insalivated. In this dog, therefore, a greatly lowered activity of several digestive glands--viz., of the gastric, pancreatic, and salivary glands--simultaneously existed. With regard to the salivary glands the circumstance was naturally submitted to closer investigation. I believe that the inhibitory influence of the alkalies on the digestive glands, which was here proved experimentally, may furnish a basis for the following representation of their mode of action in producing healing effects. Catarrhal affections of the stomach are characterised by an incessant or very protracted secretion of slimy, weakly acid gastric juice. Further, in many cases the affection begins with a hypersecretion, that is an abnormal excitability, of the secretory apparatus which makes itself evident in a superfluous and useless flow. The same must be conceived to happen in disorders of the pancreatic gland; at least such a condition sets in after operations performed for physiological purposes. It is, further, justifiable to suppose that, when an affection is once set up by this or that cause, it may later maintain itself independently; for continuous activity has undoubtedly a harmful influence on the glands. The due nourishment, and the restoration of organs after activity, proceeds best during rest. In the normal course of events, after a period of active work follows a pause, during which the latent work of restoration is accomplished. When, therefore, a remedy effectively restrains the excessive work of a diseased organ, it may in this way contribute to the removal of the pathological condition, and thus to a restoration of the normal state. In this consists, in my opinion, the healing effects of the alkalies. One might draw a parallel between the action of these substances in digestive disturbances and that of digitalis in compensatory disturbances of the heart. An uncompensated heart beats rapidly, and thereby only aggravates its condition. Its time of rest, that is of recovery, of restitution of the organ, is shortened. A vicious cycle is set up. The weak action of the heart lowers blood pressure; the lowering of this leads (from known physiological causes) to an increase in the number of beats; the quickening leads to weakening of the organ. Without doubt the digitalis aids by breaking through this vicious cycle, in that it greatly slows the pulse, and thereby gives new power to the heart. With our explanation of the action of the alkalies harmonises the further circumstance that, with the use of the salts in question, a strict diet is generally prescribed, which means that a certain amount of rest is secured for the digestive glands. It is interesting that in clinical investigations with the stomach-tube, after a period when the alkalies were looked upon as succagogues, a new phase has also set in, mention being now more frequently made of a restraining effect.

The cause of the erroneous belief that alkalies promote a flow of juice obviously lies in this, that people omitted to compare the effects of the saline solutions with those of like quantities of water (Dr. Chigin).

The second point which we may consider is the following. The chief difficulty of the physician who wishes to regulate the diet of patients when they suffer from digestive disturbances consists in the fact that idiosyncrasy plays a very important rôle. In one and the same illness, different patients react to the same diet in wholly different ways. That which is agreeable to one, and is well borne and useful, may be rank poison to another. Consequently, the golden rule in dietetics is to give no directions with regard to food till one has made inquiries concerning the inclinations and habits of the patient. What does all this indicate? Till now physiology had no experimental answer to the question. But our facts, it appears to me, contribute to a clearing up of the situation. Every food determines a certain amount of digestive work, and when a given dietary is long continued, definite and fixed types of glands are set up which can only slowly and with difficulty be altered. In consequence, digestive disturbances are often instituted if a change be suddenly made from one dietetic régime to another, especially from a sparse to a rich diet; such, for instance, as happens after the long Russian fasts. These disturbances are expressions of the temporary insufficiency of the digestive glands to meet the new demands made upon them.

Finally, it may be of some use to relate the following here. There are often cases of sudden and unaccountable digestive disturbances. From the standpoint of modern physiology they might be explained by an activity of the secreto-inhibitory nervous system, which from some cause or other has been excessively and abnormally stimulated. In any case this system is now a factor of which the physician has to take due account.

SWALLOWING AND MOVEMENTS OF THE STOMACH AND INTESTINES

BY W. B. CANNON, M.D.

Of the Physiological Laboratory of the Harvard Medical School Boston, Mass., U. S. A.

The suggestion made by Dr. Bowditch was taken up in the Harvard Physiological Laboratory and formed the beginning of a series of studies of the mechanical factors in digestion. The reports of these studies, presented by Dr. W. B. Cannon and collaborators, in the American Journal of Physiology, in the volumes of 1898 and 1903, are so understandable, even to the layman ignorant of physiological nomenclature, that we are prompted to give them, almost entire, leaving out only the technical description of the methods employed, which are only interesting to research students who have access to the Journal.

It will be noted that three of the professors of physiology mentioned in connection with this preliminary study of the nutrition problem--Bowditch, Mosso, and Kronecker--are members of our presently organised Board.—HORACE FLETCHER.]

THE MOVEMENTS OF THE FOOD IN THE ŒSOPHAGUS

BY W. B. CANNON AND A. MOSER

From the Laboratory of Physiology in the Harvard Medical School

Extracts from American Journal of Physiology, 1898

The movements of deglutition, in common with many other physiological processes, were explained by the older physiologists on anatomical grounds. Thus, Magendie divided the act into three parts, corresponding to the anatomical regions of the mouth, pharynx, and œsophagus. The muscles of each of these divisions were considered the active agents in propelling the food onward. The function of moving the mass to the pharynx was variously ascribed to the tongue itself, to the mylohyoid muscles, and to gravity. For the second part, the movement through the pharynx, there was more unanimity of opinion, since the constrictors, especially the middle and lower, were evidently concerned.

Direct observations on the movement of swallowed masses in the œsophagus were first made by Mosso. The œsophagus of a dog was laid bare, and a transverse incision made through it, or a piece of it excised. A small wooden ball was placed in the canal below the excised part, and the animal was then stimulated to swallow. One or two seconds after the contraction of the pharyngeal muscles a peristaltic wave began to traverse the œsophagus. This wave did not stop at the point of excision, but in due time reappeared below, and carried the ball to the stomach. Thus the act was shown to be controlled by the central nervous system. Peristalsis was so plainly the motive power that the action was never doubted. Yet this belief was soon to be questioned.

In 1880 Falk and Kronecker studied the movements in the mouth and pharynx, and advanced the theory that deglutition was accomplished by the rapid contraction of the muscles of the mouth. During the act of swallowing the air-tight buccal cavity shows a manometric pressure of twenty centimetres of water. The same pressure was demonstrated to be present also in the œsophagus, but not in the stomach. This pressure was considered sufficient to force food through the œsophagus before the peristaltic wave traversed it. Another argument for rapid descent was found in the fact that cold water can be felt in the epigastric region almost immediately after being swallowed. Further, when strong acids pass through the gullet, they corrode but small parts of it, and not the entire mucous membrane, as would be the case were the acid carried to the stomach by peristalsis.

Over a year and a half ago it was suggested by Prof. H. P. Bowditch that if some substance opaque to the Röntgen rays were swallowed, it could be seen in its passage to the stomach, and the nature of its movement thus determined. Anæsthesia could be dispensed with,--a desirable condition, since observers had found that it interfered greatly with the deglutition reflex. It would be unnecessary to open either the abdominal or the pleural cavity. The reflex stimulus of food, moreover, would be better than electrical stimulation of the superior laryngeal nerve. In short, the animal would swallow normal food under practically normal conditions. At Dr. Bowditch’s suggestion and with his valuable assistance--which we gratefully acknowledge--we made the following series of experiments.

To render the swallowed mass opaque, subnitrate of bismuth was used. The salt is tasteless, practically inert, and can be fed in large quantities without harm. In order that observations could be made by more than one person, all experiments were conducted in a dark room. On the side of the animal opposite the Crookes tube was placed an open fluorescent screen, on which the different tissues of the animal were outlined with varying degrees of light and shade. Among these shadows the swallowed mass appeared as a darker object, and thus its motion could be studied.

For the first experiments the goose was selected. The head and neck were held stationary by a tall pasteboard collar, which allowed free movement of the head without constriction of the neck. The fluorescent screen was placed against this collar at a uniform distance of thirty centimetres from the tube. When a bolus of corn-meal mush mixed with bismuth was placed in the pharynx, it descended slowly and regularly, and occupied about twelve seconds in passing over a distance of fifteen centimetres. The screen was marked at intervals of two centimetres with cross lines, by means of which the relative rate in different parts of the œsophagus could be studied. A vibrator marking tenths of a second was interrupted whenever the bolus crossed a line. An average of over one hundred such observations showed that the rate became slightly slower as the bolus proceeded.

In order to test liquids, molasses was mixed with bismuth to such a consistency as to drop easily from a glass rod. When this was fed with a pipette, it passed slowly and regularly down the œsophagus, clearly by peristalsis. The rate was about the same as for solid food. In both these experiments the addition of water would sometimes cause irregularities in the descent. Microscopic sections from four different parts of the œsophagus of the goose showed no histological difference.

In the experiments on the cat, the animal was placed on its back and left side on a holder. The extremities were secured by straps. The head was held between two upright rods, connected above by a thong; this allowed free movement of the head, without resistance to the passage of food. Shreds of meat dipped in bismuth were ordinarily masticated and swallowed without difficulty. For soft solids, bread and milk were used, so fluid as to be easily drawn up into a pipette. The insolubility of the bismuth salt rendered the study of liquids more difficult. Strong solutions of potassic iodide and other salts, and suspension of bismuth, in acacia and molasses were tried; but a simple mixture of milk and bismuth, shaken in a test tube and immediately drawn up into a pipette, was found most practicable.

Inasmuch as the movement of these different foods varied in different parts of the œsophagus, it will be convenient to divide the latter into three sections. The first or cervical portion extends from the pharynx to the thorax; the second or thoracic, from here to the lower half of the heart; and the third comprises the rest of the canal. The relative length of these three parts is about in the ratio of 9:8:6.

The beginning of deglutition was noted by one observer by a finger on the larynx; the same observer called out when the bolus arrived at the thorax, heart, and stomach respectively, while the other observer noted the time. The movement of solids will first be considered. The descent the entire way was by peristalsis, but the rapidity varied. The duration of the movement in the cervical portion was two and a half seconds, and in the thoracic region a little less than two seconds. At the lower end of the heart there was sometimes a slight pause. In the lower section, from the heart to the stomach, the movement was decidedly different; the rate was always very slow. The distance was less than one-third of the entire canal, yet the time consumed in this part ranged from six to seven seconds, or three-fifths of the entire time of descent. The character of the movement here was also peculiar. Whereas in the upper sections the passage was uniform and regular, with a slight acceleration in the thoracic region, here it was apparently irregular, for the bolus descended about one centimetre with each inspiratory movement of the diaphragm, and remained stationary or descended very slightly during expiration. Thus a series of hitches seemed to carry the bolus to the cardia. A probable explanation of this peculiar movement is that the stomach and lower œsophagus were pulled down with each descent of the diaphragm. This would make the movement appear irregular, although it was really a slow peristalsis. It may be well to remark here that this movement was invariably observed in the cat with every kind of food.

Semi-solids, namely, a mush of bread and milk, descended in the same way as solids; but the rate was slightly faster in the upper œsophagus, for the bolus took about a second less to reach the cardiac level. From here the rate was the same as with solids.

For liquids, one and a half to two seconds sufficed for the descent to the midheart region. Here there often occurred a long pause, from a few seconds to a minute or more. Then the œsophagus apparently contracted above the liquid, which slowly passed on to the stomach, as already described. Sometimes it seemed as if a swallowing movement, evidenced by a rise of the larynx, started the peristaltic wave. Again, several swallows would succeed one another before the liquid passed on. A few times the bismuth and milk seemed strung out along the œsophagus; some more liquid descending would gather this up, and the whole mass, assuming an ovoid form, would move into the stomach.

Thus in the cat the total time for deglutition varies from nine to twelve seconds. The lowest section presents no change ascribable to a difference in consistency, while in the upper sections the rate does slightly increase with the more liquid character of the food.

In experiments on the dog, bismuth enclosed in capsules or wrapped in shreds of meat was fed as the solid. The general phenomena were as follows: With the rise of the larynx there was a quick, propulsive movement of the bolus, which descended rapidly for a few centimetres, sometimes as far as the clavicle. From this point the rapidity was diminished, yet no pause was observed; the bolus simply moved more slowly. This rate was then continued to the stomach without a slackening of speed in the diaphragmatic region, as was observed in the cat. Semi-solids moved in the same way as solids. The total time of descent from larynx to stomach was from four to five seconds.

Liquids gave even a more decided squirt in the beginning of the movement. To render the œsophagus as lax and free as possible, the head of the dog was released from the upright rods and held by the hands after the food was placed in the mouth. Sometimes the liquid descended rather rapidly as far as the heart, at other times no further than the clavicle; then without a pause it passed on slowly and regularly, reaching the stomach in about the same time as solids and semi-solids.

Thus in the dog and cat but little variation was seen in the swallowing of liquids and solids. The liquids pass somewhat faster in the upper œsophagus. But in some animals the difference of rate with foods of varying consistency is much more marked. In the horse, for instance, mere observation shows a decided variation in the rate of movement in the œsophagus. Liquids shoot along the gullet, while solids move clearly by peristalsis. To determine the rate of solids, one hand was placed on the larynx of a horse to note the beginning of swallowing, and the other hand near the shoulders, where the bolus could be easily felt in its passage. The time consumed by the bolus in passing over a certain distance was measured by a stop watch. The rate obtained for solids, such as hay or grain, was from thirty-five to forty centimetres a second.

For semi-solids, a mixture of bran and water was made, thin enough to run easily between the fingers. Each bolus was watched by a separate observer with a separate watch. The average rate obtained was the same as for solids.

Liquids in the horse pass with a rapidity too great to be affected by peristalsis. Another force must be sought. Among the various muscles supposed to be effectual in moving food into the pharynx, the mylohyoids were shown by Meltzer to be essential. The styloglossi were cut by him without much interference with deglutition, but section of the mylohyoid nerves rendered the act impossible. The activity of these muscles in the horse during swallowing is easily perceived by the hand. Their energetic contraction is a sufficient explanation of the rapid passage of water through the œsophagus. The motion here is more than five times as rapid as that of solids and semi-solids.

Meltzer’s experiment to measure the rate of liquids in man by passing a stomach tube containing litmus paper was repeated by us with some modifications. Congo red paper was used, since it is more sensitive than litmus; it also furnishes a means of differentiating between mineral and organic acids, as the discolouration produced on Congo red by mineral acids is removed by ether. It was thus possible to distinguish between the discolouration produced by gastric regurgitation and that produced by the swallowed liquid. For the swallowed liquid, one-half per cent lactic acid was found most satisfactory, as the colour produced by it on Congo red test paper is almost instantly discharged in ether. By this method the paper was found discoloured within half a second after the rise of the larynx, certainly too short a period for a peristaltic wave to carry the liquid to the neighbourhood of the cardia.

The X-ray method lends itself less successfully to the study of deglutition in man than in the other animals we have studied. The thickness of the thorax, the distance of the œsophagus from the surface, and the relation to dense tissues render the observation of a swallowed mass difficult, especially when the mass is in rather rapid motion. The few observations which we have to report were made on a seven-year-old girl, placed in the sitting posture. Gelatine capsules containing bismuth were used for solids, and were traced to a point below the heart. The motion was very regular, and apparently due to peristalsis, for the bolus descended without a hitch or irregularity of any kind. Sometimes the capsule became fixed in the upper œsophagus, at about the level of the second rib. Repeated swallows of water would fail to dislodge it. An interesting point was noted here. With each attempt at swallowing, the capsule would rise slightly, as if the œsophagus was pulled up with the rise of the larynx; then the capsule would descend to its former position.

Semi-solids--a mush of bread and milk--could be seen about as far as solids; that is, to just below the heart. The motion of the mushy bolus was the same as with solids, except that the rapidity was perhaps slightly greater.

It should be noted here that with the human subject, as well as with the horse, our results for semi-solids differ from those derived by Meltzer’s method; for according to his statements semi-solids, like liquids, are squirted down the œsophagus, and are not propelled by peristalsis, as has been the case in our observations.

Liquids--bismuth and water--were seen only in the neck and upper thorax. Here there was a decided squirt. With the rise of the larynx the liquid was seen to pass rapidly through the pharynx and well down into the thoracic œsophagus before it was lost to observation. The rate, however, by estimation was less than that of liquids in the horse.

There remains to be considered Meltzer’s latest investigation, in which he endeavoured to ascertain whether liquids remain above the cardia till the arrival of the peristalsis, or ooze down before. An experimental answer was secured by Meltzer by the following method. The abdominal and gastric walls of an anæsthetised dog were incised, and a tube (vaginal speculum) introduced. Through this the entrance of food into the stomach could be observed directly. In repeated experiments no liquid was seen to pass through the cardia before the arrival of the peristaltic wave. An incision through the diaphragm near its anterior origin showed that the swallowed liquid was not squirted as far as a point an inch above the diaphragm. To observe the œsophagus nearer its beginning, the upper three ribs were resected on the left side. Thus the swallowed liquid was seen to shoot along the œsophagus before any peristalsis reached this point. The resection of the fifth rib exposed the œsophagus half-way between the bifurcation of the trachea and the diaphragm. Here a bulging was sometimes observed immediately after the beginning of the act, and the swallowed mass remained there until a peristaltic wave carried it down. If the mass swallowed was small, or was projected with moderate force, it might not even reach as far as the bifurcation. From these experiments Meltzer concluded that in animals, as in man, liquid food is not carried down the œsophagus by peristalsis, but is thrown rapidly into a deep part of the canal. The depth reached depends on the quantity swallowed, the force used, and the tonicity of the lower part of the œsophagus.

The difference between these methods of Meltzer and those employed in our experiments has already been mentioned; and merely his results, which were obtained with liquids alone, need be considered here. According to our observations on the dog, there was no distinct pause at any part of the canal. The movement simply became slower, and continued at this rate until the stomach was reached. Neither was the rate through the diaphragmatic part of the œsophagus slower than through the thoracic. The quick propulsive movement noticed in the dog was observed with solids and semi-solids as well as with liquids, but the liquids descended further down the canal before the movement changed to the slower peristalsis. While this difference was evident to the eye, the total time consumed by liquids in passing from pharynx to stomach was not enough shorter than the time for solids and semi-solids to be determined by our measurements.

SUMMARY.

The phenomena of œsophageal deglutition as determined by our experiments may then be described as follows:—

There is a difference in swallowing according to the animal and the food which is used.

In fowls the rate is slow and the movement always peristaltic, without regard to consistency. A squirt-movement with liquids is manifestly impossible, as the parts forming the mouth are too hard and rigid. With this diminution of propulsive power in the mouth there is observed a greater reliance on the force of gravity. The head is raised each time after the mouth is filled, and the fluid by its own weight trickles into the œsophagus, through which it is carried by peristalsis.

In the cat the movement is always peristaltic, and slightly faster than in fowls. A bolus takes from nine to twelve seconds in reaching the stomach. Liquids move somewhat more rapidly than semi-solids in the upper œsophagus. In the lower or diaphragmatic part the rate is very much slower than above, and is the same for liquids as for solids.

In the dog the total time for the descent of a bolus is from four to five seconds. The food is always propelled rapidly in the upper œsophagus, and moves more slowly below. This rapid movement is frequently continued further with liquid food. No distinct pause was observed when the movement of the bolus changed from the rapid to the slower rate.

In man and the horse liquids are propelled deep into the œsophagus at a rate of several feet a second by the rapid contraction of the mylohyoid muscles. Solids and semi-solids are slowly carried through the entire œsophagus by peristalsis alone.

THE MOVEMENTS OF THE STOMACH STUDIED BY MEANS OF THE RÖNTGEN RAYS

BY W. B. CANNON, M.D.

From the Laboratory of Physiology in the Harvard Medical School

Extracts from American Journal of Physiology, 1898

Since the stomach gives no obvious external sign of its workings, investigators of gastric movements have hitherto been obliged to confine their studies to pathological subjects or to animals subjected to serious operative interference. Observations made under these necessarily abnormal conditions have yielded a literature which is full of conflicting statements and uncertain results. The only sure conclusion to be drawn from this material is that when the stomach receives food obscure peristaltic contractions are set going, which in some way churn the food to a liquid chyme and force it into the intestines. How imperfectly this describes the real workings of the stomach will appear from the following account of the actions of the organ studied by a new method. The mixing of a small quantity of subnitrate of bismuth with the food allows not only the contractions of the gastric wall, but also the movements of the gastric contents to be seen with the Röntgen rays in the uninjured animal during normal digestion. An unsuspected nicety of mechanical action and a surprising sensitiveness to nervous conditions have thereby been disclosed.

INTRODUCTORY LITERATURE

The early writings on the subject of gastric movements are characterised by general inferences from physical laws and from the anatomical structure of the stomach. According to Galen the stomach had four functions: to draw the food from the mouth (facultas attractrix), to retain the food (facultas retentrix) during the process of chemical digestion (facultas alteratrix), and, finally, to pass the changed material onward (facultas expultrix). In later writings the facultas attractrix failed to appear as one of the functions of the stomach. Fallopius, in the sixteenth century, changed the notion of the facultas retentrix by suggesting that the pylorus alone performed this office, and that the muscles of the gastric wall could help only by remaining quiet. Thus the facultas alteratrix and the facultas expultrix are left as true gastric functions. It is with the latter activity and its effects that this paper is concerned.

The ideas of the early writers concerning the pylorus and cardia are of interest. The cardia, they were agreed, is closed during normal digestion in order to keep the food from re-entering the œsophagus. The pylorus they looked upon as the ruler of the actions of the stomach. Such names as pylorus (keeper of the gate), janitor justus, and rector, which the first investigators gave to the sphincter, indicate their theories of its functions. The passage of chyme into the duodenum, the keeping of undigested food in the stomach, the act of vomiting, were all dependent, they believed, on the “will” of the pylorus.

No substantial advance was made beyond these hypotheses until the beginning of the eighteenth century, when Wepfer and Schwartz applied the experimental method to the study of the gastric movements and laid the foundation of a more accurate knowledge. Wepfer vivisected wolves, dogs, and cats, and observed constrictions following stimulation of the stomach. He remarked a general contraction of the pyloric part in vomiting and noted peristaltic and antiperistaltic movements passing over the organ. About the middle of the stomach he frequently saw a deep constriction. The investigations of Schwartz are more valuable in that his search was for the normal action of the muscular coats. The movements, as he observed them, were generally only slight. They began either at the pylorus and passed to the left, half-way to the cardia, or started at the fundus and went to the pylorus. The contractions and relaxations, following one another, formed larger or smaller depressions and elevations, i. e., more or less definite waves.

Near the middle of the last century Haller, after confirming the results obtained by Schwartz and Wepfer, summarised his knowledge of the motor functions of the stomach as follows. In general, contraction alternates with relaxation, so that the stomach is, now here, now there, made narrower by longitudinal or transverse depressions; then in these same places relaxation and bulging occur. So long as both apertures are closed the food is driven hither and thither by the shifting movements. It first takes a definite direction when the cardia or the pylorus opens. If the cardia opens, there is an antiperistalsis followed by regurgitation and vomiting. If, on the contrary, the pylorus relaxes, a contraction, starting at the œsophagus, pushes the contents of the stomach into the duodenum. The pylorus allows the passage of fluids, but if it be stimulated by over distention or by hard pieces of food, it closes tightly.

Such was the knowledge of gastric movements in Haller’s time. A comparison of his descriptions with those in any standard work on physiology published ten or fifteen years ago will show that, despite very many researches, little advance had been made. Examinations of animals and men with gastric fistulas, studies of the stomach through the atrophied abdominal wall, and vivisection have yielded numerous results; but these have not been harmonious, and have led to much controversy. Prominent in this mass of material as a valuable contribution are Beaumont’s careful observations through the gastric fistula of Alexis St. Martin. Beaumont’s work has recently been confirmed by Hofmeister and Schütz, who, with Rossbach, Hirsch, Openchowski, and others, have presented during the last twelve years much new and interesting information. Since, however, it will conduce to clearness to set forth the results of these investigations in connection with my own work, their consideration will be deferred until later.

It will then appear that these later investigations, like the earlier researches, disagree as to the details of the stomach movements. Such differences in results are the proper outcome of the abnormal conditions under which the studies have been conducted. Obviously, in order to see the natural movements of the stomach, the organ should be observed in its natural state, and not after it has been disturbed by removal from the abdomen, or by the adhesions and losses of substance incident to gastric fistulas.

As a means of watching the gastric motor activities under normal circumstances, Dr. H. P. Bowditch, in the autumn of 1896, suggested the use of the Röntgen rays. The present paper is the result of the work thus far completed. The kind assistance and stimulating counsel of Dr. Bowditch throughout the investigation are gratefully acknowledged.

THE ANATOMY OF THE STOMACH AND ITS RELATIONS TO THE SHADOW

It must be constantly borne in mind that the shadows described in this research are cast by the gastric contents, not by the stomach itself. Therefore the movements of the organ are not seen directly, but are indicated by their effect on the contained food. Variations in the length and breadth of the stomach can be inferred from changes in the outline of the shadow, but variations in the front-to-back diameter of the organ must be judged from changes in the intensity of the shadow.

The form of the active stomach soon after food has been taken is shown in outline in Figure 1. Since the several parts of the stomach are to be mentioned frequently, it will be well to recall them here in their relations to the outline. The larger, cardiac part of the organ lies to the left of a line through w x. Into it the œsophagus opens through the cardiac sphincter, or cardia, at c. The pyloric part, which includes all of the stomach situated at the right of a line w x, is closed by the pylorus at p. This part has two divisions: the antrum at the right of the line y z, and the preantral part of the pyloric portion, or middle region of the stomach, between the lines w x and y z. The lesser curvature corresponds approximately to the anterior border of the shadow c w p; the greater curvature to the more extensive sweep, c p, along the posterior border.

The wall of the cat’s stomach consists of three coats, but as this paper deals only with the functions of the muscular coat, that alone will be described. The gastric muscular fibres are disposed in three sets: an outer longitudinal layer, a middle circular layer, and a set of inner oblique fibres. The longitudinal fibres continue those of the œsophagus, and, radiating over the cardiac end, become more marked along the curvatures than on the front and back surfaces. Over the antrum they lie in a thick, uniform layer. The circular fibres form a complete investment, and are arranged in rings at right angles to the curved axis of the stomach. Towards the pyloric end they become denser and stronger, and at the pylorus form a thick bundle, the pyloric sphincter. Separating the antrum from the rest of the stomach, at y z, is a special thickening of the circular fibres, called by the early writers the “transverse band,” and described by Hofmeister and Schütz as the “sphincter antri pylorici.” The oblique fibres start from the left of the cardiac orifice and pass as two strong bands along the anterior part of the dorsal and ventral surfaces, giving off fine fasciculi to the circular musculature; towards the antrum they gradually disappear.

The musculature of the stomach consists of smooth muscle fibres, the chief physiological characteristics of which are slowness of contraction, rhythmic alternation of contraction and relaxation, and a very great tonicity, or power of prolonged contraction. The action of these muscles in the process of gastric digestion is now to be considered.

THE NORMAL MOVEMENTS OF THE STOMACH

Since the time of Haller the chief contributors to the knowledge of the mechanics of the stomach have been Beaumont, Hofmeister and Schütz, and Rossbach.

Beaumont’s famous investigations on Alexis St. Martin are recorded in almost all general works on physiology. Through a gastric fistula he introduced a thermometer-tube and observed how it was affected by the motions of the stomach. His conclusions are as follows: “The circular or transverse muscles contract progressively from left to right. When the impulse arrives at the transverse band, this is excited to a more forcible contraction, and closing upon the alimentary matter and fluids contained in the pyloric end, prevents their regurgitation. The muscles of the pyloric end, now contracting upon the contents detained there, separate and expel some portion of the chyme.... After the contractile impulse is carried to the pyloric extremity, the circular band and all the transverse muscles become relaxed, and a contraction commences in a reversed direction, from right to left, and carries the contents again to the splenic extremity to undergo similar revolutions.”

In close accord with Beaumont’s description of the activities of the human stomach are the records of the investigations on the stomach of dogs by Hofmeister and Schütz. They removed the stomach from the body and placed it in a moist chamber, kept at body-heat and covered with glass. Under such conditions the organ remained active for from sixty to ninety minutes. A typical movement is described by these observers as composed of two phases. In the first phase a constriction of the circular fibres, deeper on the greater curvature, starts a few centimetres from the cardia and passes towards the pylorus. As the constriction proceeds it increases in strength until a maximum is reached about two centimetres in front of the antrum. This annular contraction, called by Hofmeister and Schütz the “preantral constriction,” closes the first phase. Immediately thereafter the strong sphincter antri pylorici, or transverse band, contracts. Now, while the preantral constriction is relaxing, the sphincter antri pylorici tightens still more, and the antrum is shut off from the rest of the stomach. As soon as this has occurred a general contraction of the muscles of the antrum follows. Relaxation begins at the sphincter antri pylorici and progresses slowly towards the pylorus; it is sometimes accompanied by an antiperistaltic movement.

Although Rossbach also used dogs, his results vary considerably from those of Hofmeister and Schütz. This discrepancy is possibly accounted for by a difference in method, for Rossbach left the stomach in the body. The dogs were treated with morphia and curare, and the abdomen was then widely opened, so that the movements could be clearly seen. When the stomach was full Rossbach saw deep constrictions begin near the middle and pass in waves to the pylorus. At first these movements were weak; later, however, they became more vigorous. The fundus remained in tonic contraction about its contents and took no part in the peristalsis.

Before attempting to explain the difference in the records of these observers I shall give an account of what may be seen in a cat by use of bismuth subnitrate and the Röntgen rays.

1. Movements of the pyloric part.--Within five minutes after a cat has finished a meal of bread, there is visible near the duodenal end of the antrum a slight annular contraction which moves peristaltically to the pylorus; this is followed by several waves recurring at regular intervals. Two or three minutes after the first movement is seen very slight constrictions appear near the middle of the stomach, and pressing deeper into the greater curvature, course slowly towards the pyloric end. As new regions enter into constriction, the fibres just previously contracted become relaxed, so that there is a true moving wave, with a trough between two crests. When a wave swings round the bend in the pyloric part the indentation made by it deepens; and as digestion goes on the antrum elongates and the constrictions running over it grow stronger, but until the stomach is nearly empty they do not entirely divide the cavity. After the antrum has lengthened, a wave takes about thirty-six seconds to move from the middle of the stomach to the pylorus. At all periods of digestion the waves recur at intervals of almost exactly ten seconds. So regular is this rhythm that many times I have been able to determine within two or three seconds when a minute had elapsed simply by counting six similar phases of the undulations as they passed a given point. It results from this rhythm that when one wave is just beginning several others are already running in order before it. Between the rings of constriction the stomach is bulged out, as shown in the various outlines in Figures 2, 3, 4, and 5. The number of waves during a single period of digestion is larger than might possibly at first be supposed. In a cat that finished eating fifteen grams of bread at 10.52 A.M., the waves were running regularly at 11.00 o’clock. The stomach was not free from food until 6.12 P.M. During that time the cat was fastened to the holder at intervals of half an hour, and the waves were always observed following one another in slow and monotonous succession. At the rate of three hundred and sixty an hour, approximately two thousand six hundred waves passed over the antrum during that single digestive period.

From the above review it will be manifest that my observations of the movements of the pyloric part agree closely with those of Rossbach, but differ considerably from the harmonious results of the work of Beaumont, and Hofmeister and Schütz. Beaumont’s methods, however, may be justly criticised on the ground that the thermometer-tube which he held in the stomach was wholly unlike food and very liable to bring about unwonted contractions in so sensitive an organ as the stomach. Further, the movements observed by Hofmeister and Schütz, as Ewald has pointed out, may easily have resulted from the abnormal stimulus due to lack of blood--a potent cause of peristalsis. And it will be shown later that the accounts given by these investigators describe very well the actions of the stomach when stimulated by an unusual irritant. In this connection it may be added that since the publication of the preliminary notice of my work, Roux and Balthazard, using the Röntgen rays, have published the results of observations on the stomachs of the dog and man similar to those thus far described in this paper.

The fact that my observations and those of Roux and Balthazard were conducted under normal conditions, and that the conditions of Rossbach’s experiments were more nearly normal than those of the other observers mentioned, warrants the conclusion that the pyloric part has a more important function than that of merely expelling the contents of the stomach into the intestines. After summarising the description given by Hofmeister and Schütz, Ewald, for a priori reasons, declares: “I cannot accept this view. The plain fact that the pyloric portion secretes a strongly digesting fluid containing pepsin and hydrochloric acid proves it to be an important part for the peptonising function of the stomach.” The account of the remarkable manner in which the pyloric portion performs this function must be deferred until the movements of other parts of the stomach have been considered.

2. Movements of the pyloric sphincter.--Rossbach mars his otherwise careful work by declaring that the pylorus is tightly closed during the whole digestive period of from four to eight hours, and that then the sphincter relaxes and the peristaltic waves empty the stomach. That this is not the normal action of the sphincter has been shown by several observers. Hirsch watched dogs with duodenal fistulas and saw food come from the stomach at intervals of one-fourth of a minute to several minutes. Roux and Balthazard maintain that in dogs food enters the duodenum at the completion of each wave of constriction. Observations on the cat, however, do not support their view, but agree rather with the statement of Hirsch.

In cats fed with bread mixed with subnitrate of bismuth, ten or fifteen minutes elapse after the first constriction in the antrum before any food can be seen in the duodenum. When food does appear it is spurted through the pylorus and shoots along the intestine for two or three centimetres. Not every constriction-wave forces food from the antrum. On one occasion, about an hour after the movements began, three consecutive waves were seen, each of which squirted food into the duodenum. The pylorus remained closed against the next eight waves, opened for the ninth, but closed once more against the tenth and eleventh. For each of the four succeeding waves the sphincter relaxed, but blocked the food brought by three constrictions that followed; and in this irregular way the food continued passing from the stomach. Near the end of gastric digestion, when the constrictions are very deep, it may be that the pylorus opens for every wave.

When a hard bit of food reaches the pylorus, the sphincter closes tightly and remains closed longer than when the food is soft. This action of the sphincter was shown by giving with the regular food of the cat a dry, hard pellet of equal parts of starch paste and bismuth subnitrate about the size of a pea. The food itself contained merely enough bismuth to throw a dim shadow, near the centre of which the pellet could be clearly seen as a dark object. The continual passing of the contraction-waves finally brought the little ball to the pylorus. When it arrived there, five grams of bismuth subnitrate were introduced into the stomach through a tube in the œsophagus. This was done in order that the food passing into the intestines after the ball came to the pylorus might be distinguished from that which had gone on before. By kneading the stomach the bismuth was distributed, as shown by the uniformly black shadow. The pellet could still be seen near the end of the antrum when the constrictions passed over it. Now, although the waves continued to run regularly, the very black food did not gather in the intestines in sufficient amount to be recognised until forty-two minutes after it had been introduced. And when, finally, the food did show itself in the intestines, its shadow contrasted strongly with that of the food which had already passed on. The slowness of the expulsion is not to be regarded as wholly due to the hard mass. No doubt the kneading of the stomach mixed the contents of different parts of the organ and brought to the pylorus food not yet sufficiently digested to be passed by that selective sphincter. But this does not explain the whole delay. Food similar to that given here, except that it contained no hard particles, has usually been seen as small masses in the intestines within fifteen minutes after being swallowed. A part of the delay was evidently, therefore, caused by the hard pellet. Further evidence on this point was secured when, on one occasion, the sphincter was seen to open only seven times in twenty minutes following the arrival of a hard particle of food at the pylorus. The conclusion may therefore be drawn that hard morsels keep the pylorus closed and hinder the passage of the food into the duodenum.

3. Activity of the cardiac portion.--The part played by the fundus apparently has not hitherto been properly appreciated. It has been regarded as the place for peptic digestion, or as a passive reservoir for food; but it is in fact a most interestingly active reservoir.

The action of the cardiac portion will be best understood by comparing the appearances the stomach presents at various stages in a digestive period. In order to show these stages I carefully made a set of three tracings of the outlines of the stomach as soon as possible after a cat had finished eating, and another set of three every half hour thereafter, until the contents had disappeared (Figs. 2, 3, 4, and 5). These tracings were made by placing white tissue paper over the fluorescent screen, and drawing with a thick lead pencil, easily seen, as much of the boundary of the stomach as I could at the end of each expiration. Between the times for making the drawings the cat was allowed to rest quietly on a mat, but care was taken to lay her in the same position on the holder for every drawing. The drawings of each set were afterwards fastened over one another, so that the lines coincided as closely as possible. Another piece of tissue paper was then put over these, and all four sheets were laid on an illuminated pane of glass. It was thus easy to get a composite tracing which, considering the movement imparted to the stomach by respiration, and the dimness of the shadows in the later stages of digestion, probably represents more exactly than any single drawing the outline of the stomach for each successive period.

A comparison of these drawings shows that as digestion proceeds the antrum appears gradually to elongate and acquire a greater capacity, and that the constrictions make deeper indentations in it. But when the fundus has lost most of its contents, the longitudinal and circular fibres of the antrum contract to make it again shorter and smaller. Its change of form, however, compared with the rest of the stomach, is slight.

The first region to decrease markedly in size is the preantral part of the pyloric portion. The peristaltic undulations, caused by the circular fibres, start at the beginning of this portion, and gradually, by their rhythmic recurrence, press some of the contents into the antrum. As the process continues, the smooth muscle fibres with their remarkable tonicity contract closely about the food that remains, so that the middle region comes to have the shape of a tube (Figs. 3 and 4--1.30 P.M. to 2.30 P.M.), with the rounded fundus at one end and the active antrum at the other. Along the tube very shallow constrictions may be seen following one another to the pylorus.

At this juncture the longitudinal fibres which cover the fundus like radiating fingers, and the circular and oblique fibres reaching in all directions about this spherical region, begin to contract. Thus the contents of the fundus are squeezed into the tubular portion. This process, accompanied by a slight shortening of the tube, goes on until the shadow cast by the fundus is almost wholly obliterated (Fig. 5--5.30 P.M.).

The waves of constriction moving along the tubular portion press the food onward as fast as they receive it from the contracting fundus, and when the fundus is at last emptied they sweep the contents of the tube into the antrum (Fig. 5--5.00 P.M. to 6.00 P.M.). Here the operation is continued by the deeper constrictions till, finally (in this instance at 6.12 P.M.), with the exception of a slight trace of food in the fundus, nothing is to be seen in the stomach at all.

The food in the fundus may possibly be slightly affected by the to-and-fro movements of the diaphragm in respiration. With normal breathing the upper border of the cardiac portion swings through about one centimetre; with dyspnœa, or deep breathing, through one and a half or two centimetres. Since the lower border does not move so much, the contents are gently pressed, and then released from pressure, at each respiration. The pyloric portion is moved very little by the diaphragm, the oscillation being less than a half centimetre.

Moritz has pointed out the value of an organ like the stomach for holding the bulk of the food and serving it out a little at a time, so that the intestines may not become congested during their digestive and absorptive processes. All of the advantages supposed to be thus secured to the intestines may be claimed also for the stomach itself. For the preceding description indicates, and experiments to be described later prove, that the stomach is composed of two physiologically distinct portions: the busy antrum, over which during digestion constriction-waves are running in continuous rhythm; and the cardiac part, which is an active reservoir, pressing out its contents a little at a time as the antral mechanism is ready to receive them.

THE MOVEMENTS OF THE STOMACH IN VOMITING

The appearance of the stomach during vomiting has been studied particularly by Openchowski. He says that when an emetic is given there follows a quivering of the stomach-wall, which, beginning near the pylorus, shows itself later in the antral and middle regions of the stomach. The quivering afterwards passes into a contraction, most strongly marked in the antral part, since the peristaltic waves running down to the antrum from above are continually growing deeper. At the same time the fundus expands spherically. The increased contraction in the pyloric part drives the contents towards the more dilated portion, and thence they are forced into the œsophagus by abdominal pressure.

The same phenomena occur when a cat is given apomorphine hypodermatically. First the upper circular muscles relax and become so flaccid that the slightest movement of the abdomen changes the form of the fundus. Then there are apparently irregular twitchings of the fundus wall. Soon a deep constriction starts about three centimetres below the cardia and, growing in strength, moves towards the pylorus. When it reaches the transverse band the constriction tightens and holds fast, while a wave of contraction sweeps over the antrum. Another similar constriction follows. In the interval the transverse band relaxes slightly, but tightens again when the second wave reaches it. Perhaps a dozen such waves pass; then a firm contraction at the beginning of the antrum completely divides the gastric cavity into two parts. This same division of the stomach into two parts at the transverse band is to be seen when mustard is given. Now, although the waves are still running over the antrum, the whole preantral part of the stomach is fully relaxed. A flattening of the diaphragm and a quick jerk of the abdominal muscles, accompanied by the opening of the cardia, now force the contents of the fundus into the œsophagus. As the spasmodic contractions of the abdominal muscles are repeated, the gastric wall again tightens around the contained food. Antiperistalsis I have seen only once; then, while the cat was retching, a constriction started at the pylorus and ran back, over the antrum, completely obliterating the antral cavity.

It will be recalled that the principal difference between the movements of the stomach and their effects as described by Beaumont, and Hofmeister and Schütz on the one hand, and Rossbach, Roux and Balthazard, and myself on the other hand, is that the former observed constrictions completely dividing the stomach at the transverse band, and the antrum then squeezing its contents into the intestines; whereas the latter have seen the constrictions moving forward as narrowing rings, but not separating the gastric cavity into two parts.

With the exception of peristalsis in the antrum, the gastric movements at the beginning of emesis are almost exactly the same as those Beaumont, and Hofmeister and Schütz, declare to be the normal contractions of the stomach. Their observations were made, however, when the organ was subjected to unnatural stimulation. In the excised stomach, observed by Hofmeister and Schütz, not only were all nervous connections severed, but likewise all flow of blood to the organ was entirely stopped, and the cutting off of the blood supply is regarded as one of the most powerful predisposing causes of peristaltic action. The thermometer-tube used by Beaumont was an irritant to the stomach, as he himself admits. “If the bulb of the thermometer,” he writes, “be suffered to be drawn down to the pyloric extremity, and retained there for a short time, or if the experiments be repeated too frequently, it causes severe distress and a sensation like cramp, or spasm, which ceases on withdrawing the tube, but leaves a sense of soreness and tenderness at the pit of the stomach.” Moritz also noticed that a rubber sound introduced into the human stomach proved to be a source of irritation. It seems reasonable to suppose, therefore, that these observers did not see the normal movements, but the actions resulting from abnormal irritation.

THE EFFECT OF THE MOVEMENTS OF THE STOMACH ON THE FOOD

In my first observations on the active stomach a bulging of the stomach-wall was to be seen in front of the passing waves. But as food did not immediately appear in the intestine, and as, after the pylorus relaxed, the gastric contents did not diminish rapidly enough to allow the supposition that all of the food squeezed forward by the waves was immediately forced through the pylorus, it was assumed that a part, at least, of the food under pressure was forced back towards the cardia through the constriction-ring. This inference was stated in the preliminary notice of my work. Roux and Balthazard also observed the passage of the undulations over the pyloric part, but state merely that the function of the constrictions is the propulsion of food into the intestine, without mentioning what must be regarded as a very important function; namely, the mixing effect of the waves.

Most writers have agreed that the result of the active and passive movements of the stomach is to force the contents hither and thither, thus mixing them and the gastric juice together. Two observers, Beaumont and Brinton, have attempted to explain the manner of the mixing. Beaumont, after noting how the thermometer-tube, used by him to indicate the gastric motions, was affected, describes the circulation of the food as follows: “The bolus as it enters the cardia turns to the left, passes the aperture, descends into the splenic extremity, and follows the great curvature towards the pyloric end. It then returns, in the course of the small curvature, makes its appearance again at the aperture, in its descent into the great curvature, to perform similar revolutions.” Brinton bases his theory of the circulation of the food on an analogy between the movement of a constriction over the stomach and the passage of a septum with a central perforation along the interior of a cylinder full of liquid. The result in both cases, he declares, must be a peripheral current of advance, and a central current of return. Thus in the stomach there would be peripheral currents from the cardia along the walls of the stomach to the pylorus, where they would unite and run as an axial current back to the cardia.

Certain a priori objections may be urged against each of these conclusions. In the first place Beaumont’s observations were made on a subject having a gastric fistula, and the adhesions between the stomach and the abdominal wall would prevent the fundus from acting quite normally in relation to its contents. Beaumont’s conclusions, furthermore, are based on the movements of a thermometer-tube introduced through the fistula, and on the recognition of particles of food which he had seen before as they passed the fistulous opening: the first method, as has been shown, made the conditions in the stomach more abnormal than they were previously; the second gave uncertain knowledge of the course of the food when out of the observer’s sight. Brinton’s hypothesis states the probable movements of fluid contents acted on by a passing constriction. But it may be objected that the conditions assumed by him do not exist in all parts of the stomach. For not only is there no peristalsis visible in the fundus, but with the usual food the fundus contents are not liquid. Moreover, the constrictions at the beginning of the pyloric portion are very slight and move slowly. The food in front of them is, accordingly, not under much greater pressure than the food behind them. The axial current which might result, therefore, could not be strong enough to go far into the cardiac portion.

It is easily possible to test experimentally the validity of these two theories by watching the action of pieces of food which throw a black shadow in a dimly outlined stomach. For this purpose little paste pellets of bismuth subnitrate, with starch enough to keep the form, were given with the customary meal. These pellets, it was found, did not break up in the stomach during the gastric digestion of soft bread. Several times I have been fortunate in getting two of the little balls in the axis of the stomach and about a centimetre apart. As the constriction-wave approached them, both moved forward, but not so rapidly as the wave. Now when the constriction overtook the first ball, the ball moved backward through the constricted ring, in the direction of least resistance. The wave then overtook the second ball, and it also passed backward to join its fellow. At the approach of the next wave they were both pushed forward once more, only to be again forced backward, one at a time, through the narrow orifice. As the waves recurred in their persistent rhythm, the balls were seen to be making progress--an oscillating progress--towards the pylorus; for they went forward each time a little farther than they retreated. This to-and-fro movement of the pellets was much more marked in the antrum, where the waves were deep, than in the middle region. On different occasions from nine to twelve minutes have elapsed while the balls were passing from where the waves first affected them to the pylorus; which means that on the way they were moved back and forth by more than a half hundred constrictions.

If the pylorus does not relax, it is evident that a wave approaching it pushes the food into a blind, elastic pouch, the only exit from which is through the advancing constricted ring. The constrictions are deeper near the end of the antrum, and the rings are small; consequently, the food is squirted back through them with considerable violence. As has been noted, the pylorus opens less frequently for a while after a solid piece of food comes to it. In such a case the slow driving waves squeeze the hard morsel and the soft food about it up to the sphincter, only to have the whole mass shoot back, sometimes half-way along the antrum. Over and over again the process is repeated till the sphincter at last opens and allows the more fluid parts to pass. Hofmeister and Schütz, and Moritz have disclaimed any selective action of the pylorus, and declare that solids are driven from the pylorus to the fundus by antiperistalsis. The action of the pylorus which I have seen, however, is more like that described by the earlier investigators; for during digestion there was no antiperistalsis, and the sphincter, separating the fluids from the solids, caused the solids to remain and undergo a tireless rubbing. Frequently, when several of these balls have been given at the same time, they have all been seen in the antrum after the stomach was otherwise empty. Here they remain to be softened in time by the juices, or to be forced through the pylorus later, for solids do pass into the intestine. Thus when the teeth neglect their work the stomach attempts to perform their function; the relative inefficiency of the gastric method of grinding and its interference with the normal gastric activities point an obvious hygienic moral.

During the process of digestion the food in the cardiac portion gives no sign of currents. Balls which lie in the fundus immediately after the food is ingested keep their relative positions until the cardiac portion begins to contract, and then move very slowly towards the antrum. Moreover, the food in the fundus of a cat has the same mushy appearance when examined after gastric peristalsis had been active for an hour and a half that it had when ingested. The contents of the antrum, on the other hand, look quite different and have the consistency of thick soup. The inactivity of the food in the fundus can also be proved by feeding first five grams of bread and bismuth, then five grams without bismuth, and finally five grams again with bismuth in it. The stomach contents are thus arranged in two dark layers along the curvatures, with a light layer between. Tracings made on tissue paper show that ten minutes after peristalsis commenced the stratification had entirely disappeared in the pyloric part, but that an hour and twenty minutes thereafter the layers were still clearly visible in the cardiac region.

The value of the circulation of the food, as described by Beaumont and Brinton, lay in the supposition that the contents of the stomach were thus brought near to the secreting gastric wall, and that the gastric juice could thus more readily exert its action. Although my observations do not support their theories of mixing currents running throughout the stomach, they still show that the pyloric portion is an admirable device for bringing all of the food under the influence of the glandular secretions of that region. For, when a constriction occurs, the secreting surface enclosed by the ring is brought close around the food lying within the ring in the axis of the stomach. As this constriction passes on, fresh areas of glandular tissue are continuously pressed in around the narrow orifice. And also, as the constriction passes on, a thin stream of gastric contents is continuously forced back through the orifice, and thus past the mouths of the glands. The result of this ingenious mechanism is that every part of the secreting surface of the pyloric portion is brought near to every bit of food, before the latter leaves the stomach, a half hundred times or more, as evidence by the moving ball.

SALIVARY DIGESTION IN THE STOMACH

The absence of movement in the fundus would seem to give the food during its stay there little opportunity to become mixed with the gastric juices, and thus to undergo peptic digestion. The truth of this supposition can easily be proved experimentally by feeding a slightly alkaline meal, and later testing the chemical reaction of the contents of various parts of the stomach. A cat which had been without food for fifteen hours was given eighteen grams of mushy bread made slightly alkaline with sodium carbonate. One hour and a half after the cat had finished eating she was killed, and the stomach laid bare by opening the abdomen. A very small hole was then made through the wall in the fundus region, and another similar hole was made into the antrum. By means of a glass pipette food was extracted first from the periphery of the fundus; this food was slightly acid. The cleaned pipette was then introduced two and a half centimetres into the fundus contents, and the food thus extracted gave the original alkaline reaction. Specimens of the liquid contents of the antral and middle regions, taken from various depths, were all strongly acid. A dog killed an hour and three-quarters after eating showed similar differences between the reactions of the food in the fundus and the food in the pyloric portion. So, as a matter of fact, the food does not become acid at a uniform rate in all parts of the stomach, as would be the case if Beaumont’s and Brinton’s theories of mixing currents were true. Moreover, if the facts accorded with their notions, the saliva, which ceases to act in the presence of more than 0.003 per cent free hydrochloric acid, and is destroyed when the percentage of acid proteids is large, would manifestly have its service as a ferment limited to the relatively short time during which the stomach contents, in the process of thorough mixing, were reaching that degree of acidity. There is, however, no movement of food in the fundus, and the alkaline food received from the œsophagus remains alkaline in this region for a considerable period. The nutriment, therefore, if well chewed and thus mixed with saliva, can undergo salivary digestion in the fundus for a considerable period without interference by the acid gastric juice.

From all these observations the conclusion must be that the fundus acts as a reservoir for the food, in which the digestion of sugars and starches may take place; and that the pyloric portion with its simple but marvellous peristaltic mechanism, by a single process, triturates the food, brings it near to the active glands, stirs it thoroughly with their secretions, and expels the products into the intestines.

THE INHIBITION OF STOMACH MOVEMENTS DURING EMOTION

Early in the research a marked unlikeness was noticed in the action of the stomachs of male and female cats. The peristalsis seen with only a few exceptions in female cats failed to appear in most of the males, although both had received exactly the same treatment. Along with this difference was a very striking difference in behaviour when bound to the holder; the females would lie quiet, mewing occasionally, but purring as soon as they were gently stroked. The males, on the contrary, would fly into a violent rage, struggle to be loose from their fastenings, bite at everything near their heads, cry loudly, and resist all attempts to quiet them. On account of this difference only female cats were used for some time, and the significance at first attributed to the action of the males was almost forgotten when the following incident recalled it and suggested that the excitement caused the suspension of the stomach movements. On October 23, 1897, a male cat was fed at 12.00, but was not placed on the holder till ninety minutes later. The waves were passing at the rate of six a minute. The cat fell into a rage and the waves suddenly stopped.

A few days later an observation on a female with kittens explained the absence of gastric movements in the males. While the peristaltic undulations were coursing regularly over the cat’s stomach, she suddenly changed from her peaceful sleepiness, began to breathe quickly, and struggled to get loose. As soon as the change took place, the movements in the stomach entirely disappeared; the pyloric portion relaxed and presented a smooth, rounded outline. I continued observing, and stroked the cat reassuringly. In a moment she became quiet and began to purr. As soon as this happened the movements commenced again in the stomach; first a few constrictions were visible near the end of the antrum, then a few near the sharp bend in the lesser curvature, and finally the waves were running normally from their habitual starting-place. By holding the cat’s mouth closed between the thumb and last three fingers, and covering her nostrils with the index finger, she could be kept from breathing. At the first sign of discomfort the fingers were removed. This experiment was repeated a great many times on different cats, and invariably the evidence of distress was accompanied by a total suspension of the motor activities of the stomach and a relaxation of the antral fibres.

No amount of kneading or compression of the abdomen with the fingers, short of making the cat angry, would cause the waves to stop; so that the cat’s movements, in themselves, were not the source of the inhibition. And since expressions of strong feeling on the part of the animal always accompanied cessation of the constriction-waves, the inhibition was probably due to nervous influence. It has long been common knowledge that violent emotions interfere with the digestive process, but that the gastric motor activities should manifest such extreme sensitiveness to nervous conditions is surprising.

SUMMARY

1. By mixing a harmless powder, subnitrate of bismuth, with the food, the movements of the stomach can be seen by means of the Röntgen rays.

2. The stomach consists of two physiologically distinct parts: the pyloric part and the fundus. Over the pyloric part, while food is present, constriction-waves are seen continually coursing towards the pylorus; the fundus is an active reservoir for the food and squeezes out its contents gradually into the pyloric part.

3. The stomach is emptied by the formation, between the fundus and the antrum, of a tube along which constrictions pass. The contents of the fundus are pressed into the tube and the tube and antrum slowly cleared of food by the waves of constriction.

4. The food in the pyloric portion is first pushed forward by the running wave, and then by pressure of the stomach-wall is returned through the ring of constriction; thus the food is thoroughly mixed with gastric juice, and is forced by an oscillating progress to the pylorus.

5. The food in the fundus is not moved by peristalsis, and consequently it is not mixed with the gastric juice; salivary digestion can therefore be carried on in this region for a considerable period without being stopped by the acid gastric juice.

6. The pylorus does not open at the approach of every wave, but only at irregular intervals. The arrival of a hard morsel causes the sphincter to open less frequently than normally, thus materially interfering with the passage of the already liquefied food.

7. Solid food remains in the antrum to be rubbed by the constrictions until triturated, or to be softened by the gastric juice, or later it may be forced into the intestine in the solid state.

8. The constriction-waves have, therefore, three functions: the mixing, trituration, and expulsion of the food.

9. At the beginning of vomiting, the gastric cavity is separated into two parts by a constriction at the entrance to the antrum; the cardiac portion is relaxed, and the spasmodic contractions of the abdominal muscles force the food through the opened cardia into the œsophagus.

10. The stomach movements are inhibited whenever the cat shows signs of anxiety, rage, or distress.

THE MOVEMENTS OF THE INTESTINES STUDIED BY MEANS OF THE RÖNTGEN RAYS

BY W. B. CANNON

From the Laboratory of Physiology in the Harvard Medical School

Extracts from American Journal of Physiology, 1902

INTRODUCTION

The investigation of intestinal movements has been beset by the same difficulties that characterised the investigation of the gastric mechanism. Pathological subjects or animals subjected to the disturbing action of drugs and anæsthetics and of serious operations have been the only sources of our knowledge. A considerable difference of opinion as to the nature of the normal movements in the intestines has resulted from observations made under these necessary abnormal conditions. The slowly advancing peristaltic wave and the Pendelbewegung, or swaying movement, described by Ludwig, have been regarded as true physiological processes. Concerning antiperistalsis and the swiftly running vermicular contraction, observers are not so nearly in agreement. The activity of the large intestine has been described as simply peristalsis of a slower rate than that seen in the small intestine.

The best known of the intestinal movements is the normal peristaltic wave. This wave is slow, having a rate of about two centimetres per minute, is regular, and by most observers is said to move always in one direction. The progress of the contraction, as suggested by Nothnagel’s experiments, and as clearly stated by Mall and by Bayliss and Starling, is dependent upon a local reflex. According to Mall, when an object stimulates the mucosa there occurs above the point of stimulation a constriction which forces the object downward; and as it moves downward new regions immediately above the mass are by this reflex brought into constriction, and thus the wave and its stimulus advance together. “At the same time,” Mall states, “a sucking force, due to active dilatation below the body, may have a tendency to drag it down.” In what manner an active dilatation of the intestinal wall may occur so as to produce a “sucking force” he does not make wholly clear. Bayliss and Starling, in describing normal peristalsis in the intestine, state that the contractions above the bolus increase until there is a strong tonic constriction. This passes the bolus onward, and as it advances the ring of constriction follows it. While the bolus is passing down, the gut above it is traversed by waves running as far as the constricted ring. These observers state the law of intestinal peristalsis thus: “Local stimulation of the gut produces excitation above and inhibition below the excited spot.”

The pendulum movements are characterised by a gentle swaying motion of the coils, and are accompanied by rhythmical contractions of the intestinal wall. They continue with undiminished force after paralysis of the local nervous mechanism by nicotine or cocaine; they have been called, therefore, myogenic or myodromic contractions. Observers have described them variously as shortenings and narrowings of the gut, rhythmically repeated at nearly the same intestinal circumference; as alternating to-and-fro movements of the long axis without changes in the lumen; as local or extensive periodic contractions and relaxations mainly of the circular musculature; and as waves involving both muscular coats of the intestine, and travelling normally from above downward at a rapid rate (2 to 5 cm. per second). They have been seen in the dog, and in the rabbit and cat. In the cat Bayliss and Starling noticed that when the lumen of the gut was distended by a rubber balloon, there appeared rhythmical contractions, which nearly always were most marked at about the middle of the balloon; i. e., the region of greatest tension. This form of constriction, which, as my observation shows, is an indication of the manner in which the rhythmical contraction acts in the cat’s intestine, Bayliss and Starling seem to have regarded with slight attention, since it did not accord with the law of peristalsis.

The swift vermicular wave may pass the whole length of the intestine in about a minute. It is often seen just after death, as well as in pathological states such as intestinal anæmia or hyperæmia, and when the bowel contains gases and organic acids from decomposing food. Starling is inclined to regard this type of intestinal activity as an exaggeration of the rhythmic type; Mall, on the other hand, places it in a class by itself, and declares that its service is to rid the intestine rapidly of irritating substances. Nothnagel, who designates this form of movement with the term Rollbewegung, thinks it is transitional between a physiological and a pathological activity.

The existence of antiperistalsis has been so much questioned that it will be considered in a special section of this paper, where my observations may be conveniently introduced.

The common understanding of the manner in which food passes through the intestinal canal is that the chyme ejected from the stomach is pressed downward by a peristalsis, which passes slowly over a part or all of the small intestine. The peristaltic waves of the colon are supposed to constitute an independent group, similar to those of the small intestine, but weaker and slower. Movements of the food other than the uninterrupted advance have been mentioned by some observers. Starling states that the effect of the pendulum movement is to mix the contents of the intestine and bring them into intimate contact with the mucous membrane. Grützner writes that he has been brought “by strange and peculiar observations” to believe that the fluid contents of the small intestine move irregularly forward, then forward and back, then perhaps remain quiet for some time, only to pass backward for a long distance, and finally to move forward steadily to the end. In this manner the food is mixed and brought into contact with the absorbing walls. The to-and-fro shiftings of the food Grützner ascribed to advancing and retrograde contractions of the intestinal musculature, and he argued that even circular constrictions must force the liquid contents away in both directions. To support his contention, Grützner introduced mercury into the intestine and observed it with the Röntgen rays. After noting a backward and forward movement of the mercury he dismissed the method, saying, “Many a flash must come from the Röntgen tube before the normal movement of the intestinal contents is made entirely clear by this method.”

The following account is a summary of many repeated observations on different animals, and is a contribution to a clear understanding of the normal movements of the intestines and their contents.

THE MOVEMENTS OF THE SMALL INTESTINE

When the food has been distributed through the intestine so as to present the appearance shown in Figure 1, a noticeable feature in most or all of the loops is the total absence of movement. If the animal remains quiet, however, only a few moments elapse before peculiar motions appear in one or another of the loops, or perhaps in several, and last for some time. These motions consist in a sudden division of one of the long, narrow masses of food into many little segments of nearly equal size; then these segments are again suddenly divided and the neighbouring halves unite to make new segments, and so on, in a manner to be more fully described. I have called this process the rhythmic segmentation of the intestinal contents. Further observation reveals peristalsis here and there, and under certain circumstances the typical swaying movements may be seen. All these phenomena are now to be considered in detail.

Rhythmic segmentation of the intestinal contents.--This is by far the most common and the most interesting mechanical process to be seen in the small intestine. The nature of the process may best be understood by referring to the diagram in Figure 2. A string-like mass of food is seen lying quietly in one of the intestinal loops (line 1, Fig. 2). Suddenly an undefined activity appears in the mass, and a moment later constrictions at regular intervals along its length cut it into little ovoid pieces. The solid string is thus quickly transformed, by a simultaneous sectioning, into a series of uniform segments. A moment later each of these segments is divided into two particles, and immediately after the division neighbouring particles (as a and b, line 2, Fig. 2) rush together, often with the rapidity of flying shuttles, and merge to form new segments (as c, line 3, Fig. 2). The next moment these new segments are divided, and neighbouring particles unite to make a third series, and so on. At the time of the second segmentation (line 3, Fig. 2) the end particles are left small. Observation shows that these small pieces are not redivided. The end piece at A simply varies in size with each division; at one moment it is left small, at the next moment it is full size from the addition of a part of the nearest segment, and a moment later is the small bit left after another division. The end piece at B (probably the rear of the mass) shoots away when the end mass is divided, and is swept back at each reunion to make the large end mass again, only to be shot away and swept onward with each recurrence of the constrictions. Thus the process of repeated segmentation continues, with the little particles flitting towards each other and the larger segments shifting to and fro, commonly for more than half an hour without cessation. From the beginning to the end of a period of segmentation the food is seen to have changed its position in the abdomen to only a slight extent; whether this change is a passing of the food along the loop, or a movement of the loop itself, it is impossible to tell from the shadows on the screen. The change of position, however, is much less conspicuous than the lively division and redivision which the mass suffers so many times from the busy, shifting constrictions.

From this typical form of rhythmic segmentation there are several variations. Sometimes, and especially when the mass of food is thick, the constrictions do not make complete divisions and are so far apart that the intermediate portions are relatively large. Moreover, the constrictions do not take place in the middle of each portion, but near one end; thus each portion is constricted, not into halves, but into thirds. If a little pointer is placed at the middle of a segment, when the segments are completely divided into halves, in a few seconds the pointer will be in the middle of the clear space between two segments; but in a few seconds more the first phase will return and the pointer will again be indicating a segment,--two operations intervene between similar phases. When, however, the portions are constricted into thirds, the indicator shows it, since three operations intervene between similar phases. The manner of these changes is made clearer by reference to the diagram in Figure 3. That each portion is constricted into three pieces is proved also by watching the gradual reduction of the portion at the left end of line 1 through lines 2 and 3, and also in the gradual formation of a full-sized portion at the right end of lines 2, 3, and 4. When food undergoing this process is watched, it appears to be affected by a series of constrictions, each of which starts at one end of the mass and marches through to the other end, leaving its impress at short intervals along the length. The progression of the dotted lines from right to left in a, b, c, and d, etc., Fig. 3, gives a notion of these advancing constrictions.

Another variation of the segmentation is shown in Figure 4. In this type there are evidently divisions and subdivisions, i.e., one more operation between the appearance and the reappearance of the same phase than is present in the simple division of the small segments in a long string of food (Fig. 2). This form of segmentation is fairly typical for the constrictions seen in food advancing through the intestine. Sometimes the divisions occur in the middle of a long string of food and leave the ends wholly unaffected.

A remarkable feature in the segmentation of the food is the rapidity with which the changes take place. The simplest way of estimating the rate of division is to count, not the number of times the partition of the food recurs in the same place, but the number of different sets of segments observed in a given period. Thus in Figure 4 the appearances of lines 1, 2, 3, 4, etc., would be counted, and not merely lines 1, 4, etc. Repeated observations on different animals have shown that the most common rate of division in long, thin chains of food varies between twenty-eight and thirty times in a minute; i. e., there is a change from one set of segments to another set every two seconds, and a return of the same phase every four seconds. In some cases the rate is as low as twenty-three times per minute. The larger masses seem to be associated with a slower segmentation; the operations indicated in Figure 3, for example, occurred from eighteen to twenty-one times in a minute, so that the same phase reappeared only once in eight or nine seconds. The segmentation frequently continues for more than half an hour; in one instance it was seen to persist with only three short periods of inactivity for two hours and twenty-two minutes. At the rate of thirty segmentations per minute it is clear that a slender string of food may commonly undergo division into small particles more than a thousand times while scarcely changing its position in the intestine.

I have seen once, in a cat only lightly etherised, the exterior of an intestine which was dividing the food as above described. An hour and a half after a meal of salmon the anæsthetic was given, the abdomen opened, and the flaps raised so as to form walls. Warm salt solution was then poured into the abdominal cavity, and the floating coils left covered with the transparent omentum. The gastric peristaltic waves were running regularly; on the intestine there were visible at various places during the period of observation regions of constriction which had the appearance shown in Figure 3, except that the rings were relatively nearer together. New rings of constriction took place on the same side of all the bulging parts at the margin of the constricted portion (cf. dotted lines, Fig. 3). As new rings occurred the old relaxed, but apparently with tardiness, for the contents gurgled as if forced through the narrowed lumen. The constrictions recurred irregularly and at much longer intervals than in the normal animal. The contracted rings were pale and bloodless.

The effect of the process of rhythmic segmentation proves it an admirable mechanism. The food over and over again is brought into closest contact with the intestinal walls by the swift kneading movement of the muscles. Thereby not only is the undigested food intimately mixed with the digestive juices, but the digested food is thoroughly exposed to the organs of absorption. Mall has shown that contraction of the intestinal wall has the effect of pumping the blood from the submucous venous plexus into the radicles of the superior mesenteric vein, and thus materially aids the intestinal circulation. Moreover, lacteals loaded with fat will in a few moments become empty unless the intestine is slit lengthwise, so that the muscles cannot exert compression. The rhythmic constrictions, therefore, both propel the blood in the portal circulation and act like a heart in promoting the flow of lymph in the lacteals. This single movement with its several results is an excellent example of bodily economy; the repeated constrictions, as already shown, thoroughly churn the food and digestive fluids together, and also plunge the absorbing mucosa into the very midst of the food masses: but not only are the processes of digestion and absorption favoured by these movements; they also, by compression of the veins and lacteals of the intestinal wall, serve to deport through blood and lymph channels the digested and absorbed material.

Peristalsis.--The phenomena of peristalsis and segmentation are usually combined in some manner while the food passes through the small intestine. Peristalsis is observed normally in two forms: as a slow advancing of the food for a short distance in a coil, and as a rapid movement sweeping the food without pause through several turns of the gut. The latter form is frequently seen when the food is carried on from the duodenum; and it may readily be produced in other parts of the small intestine by giving an enema of soapsuds.

When a mass of food has been subjected for some time to the segmenting activity of the intestine, the separate segments, instead of being again divided, may suddenly begin to move slowly along the loop in which they lie. That this movement is not a swinging of the coil as a whole, but a peristaltic advance of separate rings of its circular musculature, is made probable by the fact that the succeeding segments follow along the same path their predecessors have taken. The advance of the little pieces may continue for seven or eight centimetres, when finally the front piece stops or meets other food. Then all the succeeding pieces are swept one by one into the accumulating mass, which at last lies stretched along the intestine, a solid string manifesting no sign of commotion.

Another form of slow peristalsis is frequently observed when the food is pushed forward, not in small divisions, but as a large lump. The relatively long string of food is first crowded into an ovoid form as the forward movement begins, and as it is collecting thus, it seems at the last to be suddenly formed into a more rounded ball, as if the mass were pulled or pushed together at the two ends. The next moment it is indented in the middle by a circular constriction (as shown in Fig. 4, line 2), which spreads it in both directions along the loop. The trailing portion (a) is next cut in two, and the severed part sometimes flies back over its course about a centimetre. Now the whole mass is swept together again and slightly forward as shown in line 4, Fig. 4, and the segmenting process is repeated. At stage 3, Fig. 4, a constriction sometimes appears around the middle of the advanced portion (b). Thus, with many halts and interruptions, the food slowly advances.

A slight variation of the movement just described is observed when the amount of food is greater and extends farther along the intestine. Under such circumstances, as the mass moves forward, constrictions appear just in front of the rear end, which separate it from the main body, and cause it to shoot backward sometimes through the distance of a centimetre. The main body meanwhile is not disturbed. No sooner has the rear section been shot away than it is swept forward again into union with the rest of the food, and the whole mass then advances until another interfering constriction repeats the process.

Rhythmic segmentation and the pendulum movement.--There is little doubt that the segmentation of the food which I have seen is due to an activity of the intestinal musculature similar to that which causes the so-called pendulum movement. This activity, as already noted, is rhythmic, and, although accounts differ, analytical methods prove that it involves both the longitudinal and the circular layers of muscle. Observations of the effect of the rhythmic contractions upon the food show that the action of the circular fibres is most prominent. It is probable, however, that the longitudinal fibres also play an important part in the process of segmentation. Examination of Figure 2 makes clear that in line 2 the regions of constriction appear between the regions of constriction in line 3; before c can be formed, therefore, the constriction between a and b must relax. Contraction of the longitudinal fibres between two segments would help to enlarge the constricted lumen of the gut. It seems probable that, as the constrictions on either side of c occur, the longitudinal fibres between them contract; almost simultaneously the constriction between a and b relaxes, and the two particles are thus brought swiftly together. A similar process naturally would take place for each of the shifting segments. Thus the function of the longitudinal muscles would be to contract between new rings of constriction and thereby aid in relaxing the former ring between them. During my one observation of the segmenting process, as seen on the surface of the intestine, I could not be sure that the distance between neighbouring segments was shortened as the constriction relaxed; that activity of the longitudinal fibres is present, however, is indicated by observations of Raiser on the intestines of the rabbit and the cat. Raiser observed the outer surface of the coils, and describes the normal movement as an alternate contraction and relaxation of single divisions of the longitudinal fibres; he notes that these short divisions shift. But whether they shift in alternation with the shifting circular constrictions, as seems probable, is an interesting point not yet determined.

Bayliss and Starling state that the swaying pendulum movements are essentially due to peristaltic waves recurring in the same place and running rapidly downward. This form of the movements I have seen only once. At this time about 90 c.c. of soapy water had been injected. This procedure has the effect of exaggerating in every particular the movements of the small intestine. In this instance a broad constriction appeared about the middle of a long string of food and persisted there while it spread down the gut. As the contraction spread, the gut swayed slowly to and fro before it. Then there was a relaxation, followed by a recurrence of the constriction in the same place, a spreading of the contraction, and a swinging of the loop just as before. This phenomenon was repeated again and again, till finally the string was divided and the forward piece pushed through a tortuous course to the colon.

The course of the food in the small intestine.--Chyme is not forced from the stomach by every wave that passes over the antrum, but only at intervals. When the pylorus relaxes, the food, moved towards the pylorus under considerable pressure, is squirted along the duodenum for two centimetres or more. Careful watching of this food shows that usually it lies for some time in the curve of the duodenum until additions have been made to it from the stomach, and a long, thin string of food is formed. While it is resting in this place it is exposed to the outpouring of the bile and pancreatic juices. All at once the string becomes segmented (see Fig. 5) and the process of rhythmic segmentation continues several minutes, thoroughly mixing the intestinal digestive juices with the chyme. In this region the alternate positions of the segments are sometimes far apart, and the to-and-fro movements of the particles may be a relatively extensive and very energetic swinging. Finally the little segments unite into a single mass, or form in groups, and begin to move forward. The peristalsis here, as already mentioned, is much more rapid than the normal peristalsis elsewhere in the small intestine. The masses, once started, go flying along, turning curves, whisking hither and thither in the loops, moving swiftly and continuously forward. After passing on in this rapid manner for some distance the food is collected in thicker and longer strings, resembling the strings seen characteristically in the other loops. Towards the end of digestion the small masses shot out from the stomach, after a few segmentations, may move on in the rapid course without being accumulated in a larger mass until the swift movement ceases.

During the first stages of digestion in the cat’s small intestine the food usually lies chiefly on the right side of the abdomen; during the last stages the loops on the left side contain the greater amount of food. In these loops the food remains sometimes for an hour or more with no sign of movement. All at once a mass begins to show irregular depressions and elevations along its length, and then suddenly it is divided, at first partially, later completely, into many little equal parts, and these repeatedly undergo division and reunion, division and reunion, over and over again, in the manner described above as rhythmic segmentation. After a varying length of time the activity wanes and the little segments are carried forward individually and later brought together, or join and move on as a single body, or they may reunite and lie quietly for some time without further change. Thus by a combined process of kneading and peristaltic advance the food is brought to the ileocæcal valve to enter the large intestine. Records from ten different animals show that salmon does not appear in the small intestine until an hour or an hour and a half after the food is eaten. Inasmuch as five or six hours elapse after eating before this food begins to be seen in the colon, it is evident that the chyme takes four to five hours to pass the length of the small intestine. It is interesting to note that the operations are considerably shortened if the meal has consisted of bread and milk.

THE COMPETENCE OF THE ILEOCÆCAL VALVE

The ileocæcal valve in the cat is situated three or four centimetres from the blind end of the cæcum. Its position is usually marked in shadows of the food in the colon by a slight indentation, towards which masses about to enter the colon are ordinarily directed from a point somewhat distant in the small intestine (see Fig. 6).

Regarding the competence of the ileocæcal valve many observations have been made. Grützner has reviewed the evidence bearing on the question and concludes that the valve is not competent, least of all for liquids. He declares that as soon as liquids or thin fluid masses appear in the upper part of the colon they pass in many instances into the small intestine the moment that the pressure on the colon side rises slightly. If the colon contains a solid or a thick, mushy mass, the passage towards the small intestine is scarcely possible, because every increase of pressure in the large intestine must force the two lips of the valve together and close it.

The importance of the competence of the ileocæcal valve under normal conditions cannot be appreciated until the function of the first part of the colon is considered. In order that this part of the intestinal mechanism may perform its service, the competence of the valve for the food which enters the colon from the ileum should be perfect. As a matter of fact, such is the case. Not only does the activity of the colon prove this statement, but the failure of every attempt to drive the food in the colon back through the valve into the ileum confirms the proof. Again and again I have tried, by manipulation through the abdominal wall, to press the normal contents of the colon downward with sufficient force to cause them to return to the small intestine, but without success. The valve held perfectly.

THE MOVEMENTS OF THE LARGE INTESTINE

When the large intestine is full, palpation through the abdominal wall demonstrates that the material in the lower descending colon and in the sigmoid flexure is usually composed of hard, incompressible lumps, while that in the ascending and transverse colon and the cæcum is soft, permitting the walls of the gut to be easily pushed together. The condition of the contents in these two regions seems to indicate a rough division of the large intestine into two parts, and the mechanical activities of these two parts verify the differentiation. In the descending colon the material is very slowly advanced by rings of tonic constrictions (see Fig. 7); in the ascending and transverse colon and in the cæcum by far the most common movement is an antiperistalsis.

Antiperistalsis in the colon.--The colon of cats which have been without food for a day usually contains enough gas to make the position of the gut distinguishable with the fluorescent screen (see Fig. 1). The first food to enter the colon from the small intestine is carried by antiperistaltic waves into the cæcum (Fig. 1), and all new food as it enters is also affected by these waves. Thus the contents of the colon, instead of being driven immediately toward the rectum by slow peristalsis, as is the general opinion, are first repeatedly pushed toward the cæcum by an antiperistaltic action.

These antiperistaltic waves follow one after another like the peristaltic waves of the stomach (see Figs. 5, 6, and 10). They begin either on the more advanced portion of the food in the colon (when only a small amount is present), or at the nearest tonic constriction, which is usually at the turn between the transverse and descending colon (Figs. 7 and 8.) The waves rarely run continuously for a long time. When the colon is full, it is usually quiet. The first sign of activity is an irregular undulation of the walls, then very faint constrictions passing along the gut towards the cæcum. These constrictions may first appear only on the ascending colon. As they continue coursing over the intestine they become deeper and deeper, until there is a marked bulging between successive constrictions. When the waves have thus become more prominent, they are seen to start near the end of the transverse colon and pass without interruption to the end of the cæcum. After these deepest waves have been running for a few minutes the indentations grow gradually less marked, until at last they are so faint as to be hardly discernible. The final waves are sometimes to be observed only at the end of the transverse colon.

Such a period of antiperistalsis lasts from two to eight minutes, with an average duration of four or five minutes. The periods recur at varying lengths of time; in one instance a period began at 1.38 P.M. and was repeated at 2.06, 2.34, 2.55, 3.15, and at 3.36, when the observation ceased; in another instance a period began at 2.43 P.M., and was repeated at 2.57 and at intervals of from ten to fifteen minutes thereafter while the animal was being watched. The waves have nearly the same rate of recurrence as those in the stomach; about five and a half waves pass a given point in a minute, i. e., eleven waves in two minutes. This rate has proved fairly constant in different cats and at different stages in the process of digestion; in one case, however, the waves passed at the rate of nine in two minutes.

The stimulating effect of rectal injections on the movements of the small intestine has already been noted. Enemata have also pronounced stimulating action on the antiperistalsis of the colon. Usually the almost immediate result of a rectal injection of warm water is the appearance of deep antiperistaltic waves, which often continue running for a long period. In one case, after an injection of 50 c.c. of warm water, the waves followed one another with monotonous regularity during an observation lasting an hour and twenty minutes. The manner in which this antiperistaltic mechanism affects nutrient enemata introduced into the bowel will be discussed in the section devoted to the question of antiperistalsis.

These constrictions passing backward over the colon do not force the normal contents back through the valve into the small intestine again. I have seen hundreds of such constrictions, and only twice have there been exceptions to this rule,--once under normal conditions, when a small mass slipped back into the ileum, and at another time when a large amount of water had been introduced into the colon. The importance of the competence of the ileocæcal valve is now apparent; indeed, antiperistalsis in the colon gives new meaning and value to the location of a valve at the opening of the ileum. For, inasmuch as the valve is normally competent, the constrictions repeatedly coursing towards it force the food before them into a blind sac. The effect on the food must be the same as the effect seen in the stomach when the pylorus remains closed before the advancing waves. The food is pressed forward by the approach of each constriction; but since it cannot go onward in the blind sac, and is, moreover, subjected to increasing pressure as the constriction comes nearer, it is forced into the only way of escape, i. e., away from the cæcum through the advancing constricted ring. About twenty-five waves affect every particle of food in the colon in this manner during each normal period of antiperistalsis. The result must be again a thorough mixing of the contents and a bringing of these contents into close contact with the absorbing wall--a process which has already been variously repeated many times in the stomach and in the small intestine.

Two other movements have been observed in the ascending colon, but they are rare appearances. The first of these was a serial sectioning of the contents noticed in an animal given castor oil with the food. A constriction separated a small segment in the cæcum; another constriction then cut off a segment just above the first, and with the disappearance of the first constriction the two separated segments united. A third segmentation took place above the second, and the changes occurred again. Thus the whole mass was sectioned from one end to the other; and no sooner was that finished than the process began again and was repeated several times. A slight modification of this movement was observed in a colon containing very little food. The mass was pressed and partially segmented in the manner characteristic of the small intestine, and was thus again and again spread along the ascending colon, and each time swept back into a rounded form by antiperistalsis. The second of the two movements mentioned above consisted in a gentle kneading of the contents. This was caused by broad constrictions appearing, relaxing, appearing, relaxing, over and over again, in the same place. When several of these regions were active at the same time, they gave the food in the colon the appearance of a restless undulatory mass. Once a constriction occurred and remained permanently in one place, while the bulging parts on either side of it pulsated alternately, at the rate of about eighteen times in a minute, with the regularity of the heart-beat. Although these phenomena are somewhat striking, they are not usual, and are in no way so important as the antiperistalsis.

The changes when food enters the colon.--The passage of food through the ileocæcal valve seems to stimulate the colon to activity. As food is nearing the ileocæcal valve the large intestine is usually quiet and relaxed (Fig. 6, 4.00), though occasionally indefinite movements are to be observed; and sometimes just before the food reaches the end of the ileum the circular fibres of the colon in the region of the valve contract strongly, so that a deep indentation is present there. The indentation may persist several minutes; it disappears as the muscles relax just previous to the entrance of the food. The food is moved slowly along the ileum and is pushed through the valve into the colon. The moment it has entered a strong contraction takes place all along the cæcum and the beginning of the ascending colon, pressing some of the food onward, and a moment later deep antiperistaltic waves (Fig. 6, 4.03) sweep down from the transverse colon and continue running until the cæcum is again normally full, i. e., for two or three minutes.

The appearance of tonic constrictions.--It has already been noted that as the food accumulates in the ascending colon it is at first confined to this region by antiperistaltic waves. With further accessions, however, the contents naturally must be pressed more and more into the transverse and descending colon. In the early stages of this accumulation, while the food lies chiefly in the ascending colon, the only activity of the muscular walls is the antiperistalsis. As the contents extend along the intestine a deep constriction appears near the advancing end and nearly separates a globular mass from the main body of the food (Fig. 6). The contents of the large intestine progress farther and farther from the cæcum; meanwhile new tonic constrictions appear which separate the contents into a series of globular masses. And as the number of these divisions increases they take a position farther from the cæcum, so that they are present chiefly in the descending colon (Fig. 7). Raiser has recorded a similar appearance in the terminal portion of the rabbit’s colon, in which deep circular constrictions separate the scybalous masses. He maintains that these masses are pushed onward by the constrictions. Comparing tracings made at rather long intervals (forty-five minutes), I found that the rings disappear from the transverse colon, and then are present with the waste material in the descending colon. Thus in the cat also these rings, which seem with short observation to be remaining in one position, are in reality moving slowly away from the cæcum, pushing the hardening contents before them. The contents at this stage are no longer fluid, and consequently they must offer considerable resistance to a force pushing them through the colon. It is an advantage to have this pultaceous substance propelled in divisions rather than in a uniformly cylindrical mass, since the fibres along the length of the mass are thereby rendered effective. Such are the functions of the persistent rings; they form the waste matter into globular masses at the end of the transverse colon and slowly push these masses onward.

In the transverse colon, which is free from the slowly moving rings, the antiperistaltic waves have full sway. In the region of the tonic rings an infrequent or even a slowly periodic relaxation and contraction are often to be observed. These changes seem to take place in all the rings at about the same time. Once I saw antiperistaltic waves running over the uppermost of four segments, but since the rings on either side of the segment held tightly, the waves had merely the effect of churning the material of the segment and did not move it onward. Inasmuch as the material in these segments at first is soft, so that the segments are easily compressible, while the fæcal masses which are the final result are relatively hard and dry, it follows that even within the confines of these persistent rings some absorption is taking place.

DEFECATION

The process of clearing the colon is a process of repeated reduction of the amount of material present. Figure 8 (3.11) is a radiograph showing the food in the colon at 3.11 P.M. About 3.25, with a slow, sweeping movement, the gut swung around so that the ascending colon was lying in the position of the last half of the transverse colon, and the transverse colon had taken the position of the descending part (Fig. 8, 3.25). At the same time the tonic constrictions disappeared and were replaced by a strong, broad contraction of the circular muscle, tapering the contents off on either side in two cones. The region of strongest contraction was apparently drawn downward with the rest of the gut by a shortening of the descending colon. As the intestine swung around, more material was forced into the rectum, and when the swinging of the intestine stopped, the constriction which divided the lumen passed slowly downward, and with the aid of the muscles surrounding the abdominal cavity, pushed the separated mass out of the canal. After the terminal mass had thus been pushed out, the colon with the remainder of its contents returned to nearly its former position (Fig. 8, 3.46). About two hours afterward this remnant had been spread throughout the length of the large intestine by means of the slowly moving rings. Figure 7 is a radiograph of the same colon pictured in Figure 8; the radiograph was taken at 11.50 A.M., and at 12.15 P.M. the material in the lower descending colon was forced out in the manner above described. Within three hours the remaining portion had been spread into the evacuated region, as shown in Figure 8, 3.11. The manner in which the material is spread from the region of the antiperistaltic waves into the region of the slowly advancing rings presents a problem. During normal living new food constantly arriving in the colon must force the old contents forward just as the later parts of a meal force forward the earlier parts; there is no doubt, however, that most of the contents of the cæcum and the ascending colon may be passed onward even during starvation. The emptying of these regions, according to my observations, is never complete; for after considerable time has elapsed and the large intestine is cleared and dilated with gas, some substance is still to be detected in the cæcum and clinging to the walls of the ascending colon. The only activities manifested here are the antiperistaltic waves and the strong tonic contraction of the whole circular musculature shown in Figure 6. It is clear that the latter activity would serve to press into the transverse colon a considerable portion of the contents of the ascending colon, and the remnant seen clinging to the walls would be the part not thus pressed forward.

FIGURE 8.--Two radiographs and a tracing showing the changes taking place in defecation. 3.11, material in the colon. 3.25, colon carried downward and terminal mass separated. 3.46, after defecation, when the colon returns to former position. Defecation occurred at 3.27.]

Twice I have seen appearances which might account for the emptying of the first portion of the large intestine in a more thorough manner than that above described. At one time, without apparent stimulation, strong tonic contraction occurred along the entire length of the ascending colon, which forced the contents almost wholly into the transverse portion. This action seemed merely an exaggerated form of that observable after food passes the ileocæcal valve (see Fig. 6). At another time, after a mass of food had passed through the ileocæcal valve, after the ascending colon had contracted generally and the antiperistaltic waves had coursed over it in the usual manner, a deep constriction appeared at the valve and ran upward without relaxation nearly the length of the ascending colon, pushing the contents before it. For an instant the wave paused; then the constriction relaxed and the food returned towards the cæcum. These observations indicate that either a general contraction of the wall of the large intestine or a true peristalsis may be effective in pressing waste matter from the region where antiperistalsis is the usual activity into the region where the slowly advancing rings may carry it on to evacuation (see Fig. 7).

THE QUESTION OF ANTIPERISTALSIS

In 1894 Grützner published an observation and made an assumption about which there has since been much controversy. He maintained that when normal salt solution, holding in suspension hair, powdered charcoal, or starch grains, is injected into the rectum, it is carried upward into the small intestine and may even enter the stomach. These experiments have been repeated by several observers. Some have confirmed Grützner’s results; others have failed, after using most careful methods, to find any evidence of the passage of the injected material back to the stomach, and they have declared that the apparent success was due to carelessly allowing the food of the animal to become contaminated with the test materials, so that these were introduced into the stomach by way of the mouth. That antiperistalsis does not occur in the small intestine seems to be proved by Mall’s experiment of reversing a portion, sewing it in place, and then finding that the food does not pass the reversed region, but collects at the upper end. Sabbatani and Fasola reversed stretches of small intestine of varying length, and found that the reversed portions allowed fluids to pass, but that the persistence of the physiological direction of movement caused an accumulation of undigested food in the region of the upper suture. However a portion of the intestine lay in relation to the rest, it always manifested the normal peristalsis. Many other observers working directly on the intestine confirm this testimony and state that the progress of the constriction-rings is always downward, and that antiperistalsis is not physiological. In 1898, however, Grützner took his stand again in favour of a backward movement in the intestines, and in a somewhat metaphysical manner argued that peristalsis and antiperistalsis belong to each other just as relaxation of muscle is related to contraction. He assumed that as the contents are advanced by slow peristalsis, so are they returned by a similar movement in the opposite direction, and he mentions several pathological cases (fistula of intestine) to substantiate the assumption.

By means of the X-rays it is possible to see just what takes place when a fluid is injected into the rectum. For the purpose of determining how nutrient enemata are received and acted upon in the intestines, I have introduced thin, fluid masses in large and small amounts, and thick, mushy masses in large and small amounts, in different animals. The enemata consisted of 100 c.c. of milk, one egg, ten to fifteen grams of bismuth subnitrate, and two grams of starch to hold the bismuth powder in suspension. To make the thick enema all these were stirred together and boiled to a soft mush; to make the thin enema all the parts were boiled together except the egg, which was added after the boiled portion was cooled. The small amount injected was 25 c.c.; the large amount almost 90 c.c., about the capacity of the large intestine when removed from the body. The animals were given first a cleansing injection, and after this was effective the nutrient material was introduced. In order to make sure of the observation, a control radiograph was first taken to show no bismuth food present, and other radiographs taken at varying intervals after the injection to record the course the food was following.

FIGURE 9.—- Radiographs showing that after a large nutrient enema (about 90 c.c.) has been given the food is forced more and more from the large into the small intestine. The enema was introduced at about 1.40 P.M. At 3.00 segmentation was occurring in many loops.]

These experiments show that when small amounts of nutrient fluid are introduced they lie first in the descending colon. In every instance antiperistaltic waves are set going by the injection, and the material is thereby carried to the cæcum. When large amounts are injected they stop for a moment in the region between the transverse and descending colon, as if a constriction existed there. Then a considerable amount of the fluid passes the point, and antiperistaltic waves carry it to the cæcum. In any case the repeated passing of the waves seems to have the effect of promoting absorption, for in the region where these waves continue running, the shadows become gradually more dim, and finally the bismuth appears to be only on the intestinal walls; in other regions, e. g. in the descending colon, the shadows retain their original intensity. Small injections have never in my experience been forced even in part into the small intestine; but with the larger amounts, whether fluid or mushy, the radiographs show many coils of the small intestine containing the bismuth food.

The passage of the injected material beyond the ileocæcal valve is probably due entirely to antiperistalsis in the colon,--a factor unknown to both Grützner and his opponents. The valve, which is thoroughly competent for food coming normally from the small intestine into the large, is curiously incompetent for a substance, even of the consistency of thick cream, introduced in large amount by rectum. When the valve first permits the food to enter the ileum, the fluid pours through and appears suddenly as a winding mass occupying several loops of the intestine (Fig. 9, 1.50, about ten minutes after the injection). The mass is continuous from the valve to the other end; antiperistalsis is therefore not visible in the small intestine under the circumstances of this experiment. The antiperistaltic waves of the colon, however, continue running; the transverse and ascending colon are thus almost emptied, and the small intestine more and more filled with food (Fig. 9, 2.15 and 3.00). After a short time the typical segmenting movements can be seen in the loops, busily separating the food into small masses, and over and over again dividing and redividing them.

I have never seen food material pass back from the colon so far as the stomach; but once, about ten minutes after an injection of 100 c.c. of warm water, the cat retched and vomited a clear fluid resembling mixed water and mucus. In the fluid were two intestinal worms still alive.

The importance of the mechanism by which nutrient enemata are passed backward in the intestine is evident. In the colon the nutrient material is worked over by the antiperistaltic waves, intimately mixed with whatever digestive juices may be present, and exposed to the organs of absorption in that region. If the enemata are large, the digestive and absorptive processes are by no means confined to the colon, but may take place along extensive surfaces of the small intestine. I have repeatedly seen rhythmic segmentation active throughout many loops of the small intestine, thus exposing the injected food to the same mixing and absorbing processes as affect the nutriment which has come through the stomach in a normal manner.

THE EFFECT OF EMOTIONS AND SLEEP

Observations on the stomach of the cat showed that the peristalsis is inhibited whenever the animal manifests signs of anxiety, rage, or distress. Since the extrinsic innervation of a large part of the intestinal tract is the same as that of the stomach, it is of interest to note the effect of emotional states on the movements of the intestines. Esselmont, in a study of the dog’s intestine, noted constantly after signs of emotion a marked increase of activity lasting for only a few moments. Fubini also observed that fear occasioned more rapid peristalsis. There is no doubt that many emotional states are a strong stimulus to peristalsis, but it is equally true that other emotional states inhibit peristalsis. In the cat the same conditions which stop the movements of the stomach stop also the movements of the intestines.

The female cats used in these observations ordinarily lie quietly on the holder and make no demonstration. Sometimes, however, with only a little premonitory restlessness, the cat suddenly flies into a rage, lashing her tail from side to side, pulling and jerking with every limb, and biting at everything near her head. During such excitement, and for some moments after the animal becomes pacified again, the movements, both of the large and small intestine, entirely cease. Such violence of excitement is not necessary to cause the movements to stop; a cat which was restless and continually whining while confined to the holder showed no signs of intestinal movements during any period of observation (one period lasted more than an hour), although the changes in the distribution of the food observable from one period to the next proved that movements were going on during the quiet intermissions. In another cat, uneasy and fretful for fifty minutes, no activity was seen; then she became quiet for several minutes, and peristalsis of the small intestine appeared.

When the segmentation process in the small intestine is stopped by excitement the segments unite and the series of parts returns to the form of a solid string. The change occurring in the large intestine when the antiperistalsis is inhibited by excitement is shown in Figure 10. The tonic constrictions in the descending colon are apparently not affected by emotional states, for they do not seem to relax in the excitement which causes the movements to cease.

By holding the mouth and nostrils closed, or by pressing between the rami of the jaw, the breathing may be stopped. As soon as the cat shows distress from lack of breath every form of intestinal movement stops.

The statement is sometimes made in text-books of physiology that the gastric and intestinal mechanisms cease to act during sleep. It is worthy of note that nearly all the animals curled up and slept during the time between observations; nevertheless, the progress of the food through the intestines continued. The statement is also made that at night, even without sleep, the intestines are almost entirely at rest; that this is their normal time for repose. I have seen both large and small intestines actively at work, however, from half past nine until half past ten o’clock at night.

SUMMARY

1. Bismuth subnitrate, 10 to 33 per cent, mixed with the food renders the movement of the intestinal contents, and thereby the movements of the intestinal walls, visible on the fluorescent screen.

2. The activity most commonly seen in the small intestine is the simultaneous division of the food in a coil into small segments, and a rhythmic repetition of the segmentation each time applied to the new segments formed from parts of those just divided. In the cat this rhythmic segmentation may proceed at the rate of thirty divisions per minute. The effects of the constrictions causing the segmentation are the mixing of the food and the digestive juices, the bringing of the digested food into contact with the absorbing mechanisms, and the emptying of the venous and lymphatic radicles of their contents by compression of the intestinal wall.

3. Peristalsis is usually combined with segmentation. As the food is advancing, interfering constrictions often separate the rear end of the mass from the main body. The separation is momentary, however; the rear end is swept into union with the main body again, and the whole mass is pushed onward until another constriction repeats the changes.

4. The ileocæcal valve is thoroughly competent for food entering the colon from the ileum.

5. The usual movement of the transverse and ascending colon and the cæcum is an antiperistalsis. This recurs in periods about every fifteen minutes, and each period lasts commonly about five minutes; the waves recur during a period at the rate usually of eleven waves in two minutes. This antiperistalsis gives new significance to the ileocæcal valve; for the food, now in a closed sac, is thoroughly churned and mixed by the constrictions running towards the cæcum, and again exposed to absorbing walls without any interference with the processes in the small intestine.

6. As soon as new food enters the large intestine a strong general contraction takes place along the cæcum and ascending colon, forcing some of the food onward; a moment later antiperistaltic waves begin to pass.

7. With the accumulation of material in the transverse colon, deep tonic constrictions appear one after another and carry the material into the descending colon, leaving the transverse and ascending portions free for the antiperistaltic waves.

8. In emptying the large intestine the material in the lower descending colon is first carried out by combined peristalsis and pressure of abdominal muscles; the remainder of the material is then spread into the evacuated region, and this region is again cleared; the second remainder may be similarly affected. In normal life the new food arriving in the colon must force forward the old contents of the ascending and transverse colon.

9. The observations have revealed no evidence of antiperistalsis in the small intestine, but since the ileocæcal valve will allow nutrient material under pressure to pass backward, the antiperistalsis of the large intestine may force into the small intestine a considerable portion of a large nutrient enema. Segmentation in the small intestine affects such an enema precisely as it affects food which has passed normally through the stomach.

10. Signs of emotion, such as fear, distress, or rage, are accompanied by a total cessation of the movements of both large and small intestines. The movements continue in the cat both during sleep and at night.

THE BATTLE CREEK LABORATORIES

THE MAMMOTH SANITARIUM AND THE LARGE ADOPTED FAMILY OF DR. AND MRS. J. H. KELLOGG

It may be said here, however, that the trial of thorough mouth-work as an aid to digestion, which has been in progress at the Sanitarium for more than a year, and which has finally been accepted and prescribed as the first requirement of the treatment of patients, is of the utmost significance. This is, by far, the largest sanitarium in the world, having some hundreds of physicians, nurses, and other attachés, and treating many thousands of patients annually. The “cure” is based upon natural methods of recuperation, and while all of the staff, both medical and surgical, are fully equipped diplomatists, and whereas the organisation has a legally and professionally accepted medical school of its own, so-called medicines are rarely used, and never except as antidotes to specific poisons. Nature is assisted by scientific means to do the curing, and now that an economic nutrition to relieve the exhausted system of the patient from all possible strain through ample mouth-treatment of food, as intended by the anatomical, dental, and chemical plan on which man is constructed, has been tried and accepted as a fundamental principle of the institution, it gives a practical indorsement of the claims set forth in “Glutton or Epicure,” and in this present book, and declares that they are of greatest importance in securing health and efficiency.

The Battle Creek Sanitarium is a philanthropic and humanitarian institution operating under a perpetual charter which compels the use of all the profits gained to foster the spread of the humanitarian work. More than sixty branches of the parent institution have been established in or near large cities in different parts of the world, under the title of The American Medical Missionary Association, and each of these branches conducts a life-saving business on Good Samaritan principles. The organisation started its medical missionary work some thirty-seven years ago, with almost no capital and only one patient, in a small two-storey frame house, in the then small village of Battle Creek, Michigan. The incorporators were religious enthusiasts who believed that Christianity should be expressed in works as much as in faith, in curing the sick and healing the wounded, and thus preparing the unfortunate for the reception of moral and spiritual inspiration.

The best evidence that this scheme of procedure to attain the ultimate end was a good one is shown by the success of the institution in its growth from such small beginning to the immense proportions of the present time, with one of its buildings nearly a thousand feet in length and five storeys in height and numerous other buildings radiating from the main one and scattered about it in a finely wooded park. Fire came and destroyed the old building and all its contents, but yet it was soon rebuilt, and the concern goes on growing and growing, because the foundation principle of the institution is the beautiful Golden Rule, and the method of treatment employed is taken from the open book of Nature.

While the organisation was primarily based upon a special religious creedal enthusiasm, it has become so broadly altruistic as to suggest a return to original Christianity as defined in the Sermon on the Mount. In such Christian expression honest agnostics, born Buddhists, and the tolerant of all the different Christian creeds may join and say amen!

One of the splendid results of an economic nutrition, attained by following the natural requirements and impulses, is the curing of many diseases, among them several forms of constipation. The writer has a genuine admiration for the spirit that is the motive power of the Battle Creek Sanitarium and firm belief in the Christianity demonstrated in the work, especially in the private experiment of Dr. and Mrs. Kellogg, with their family of adopted waifs. Twenty-four children of unfortunate parents, waifs so unfortunate in their attractability as to be hopelessly neglected, have been gathered under this sheltering roof and are showing their mettle and gratitude by splendid behaviour and brilliant accomplishment in a manner that any proud parent might approve. To miss any opportunity to express gratitude to Dr. and Mrs. Kellogg for giving us such a splendid example of the true meaning of practical Christianity would be showing symptoms of the worst form of constipation; viz., constipation of appreciation and affection.—HORACE FLETCHER.]

EXPERIMENTAL INVESTIGATION OF THE INFLUENCE OF MASTICATION AND COOKING OF FOOD, ETC., IN THE LABORATORIES OF THE BATTLE CREEK, MICHIGAN, SANITARIUM, UNDER THE DIRECTION OF DR. J. H. KELLOGG

From Modern Medicine

The table clearly shows the effect of cooking and the effect of mastication upon the salivary digestion of food. Column 1 shows the results obtained after an ordinary test meal consisting of 1½ ounces of water biscuit to 8 ounces of water; column 2, 1½ ounces of water biscuit ground fine, mixed with water and swallowed without chewing; column 3, test meal consisting of 1½ ounces of raw wheat flour and 8 ounces of water; column 4, test meal consisting of 1½ ounces of unground pearled wheat with 8 ounces of water.

═════════════════════════════════╤════════╤════════╤══════╤══════ │ Water │ Water │ │ │biscuit,│biscuit,│ Raw │ Raw │ well │ not │flour.│wheat. │chewed. │chewed. │ │ │ 1 │ 2 │ 3 │ 4 —————————————————————————————————┼————————┼————————┼——————┼—————— Total acidity (A) │ 0.142 │ 0.140 │0.204 │0.136 Calculated acidity (A´) │ 0.156 │ 0.132 │0.186 │0.128 Total chlorine (T) │ 0.296 │ 0.284 │0.332 │0.272 Free HCl (H) │ 0.050 │ 0.028 │0.056 │0.052 Combined chlorine (C) │ 0.106 │ 0.104 │0.130 │0.076 Fixed chlorides (F) │ 0.114 │ 0.152 │0.146 │0.144 Maltose (M) │ 1.088 │ 0.272 │0.000 │0.000 Dextrine and soluble starch (D) │ 0.812 │ 0.548 │0.300 │0.448 │ │ │ │ COEFFICIENTS │ │ │ │ │ │ │ │ Digestion of albumin (a) │ 0.82 │ 0.97 │1.00 │1.00 Digestion of starch (b) │ 0.71 │ 0.42 │0.00 │0.00 Salivary activity (c) │ 1.17 │ 1.11 │1.14 │1.37 Fermentation (x) │ 5.00 │ 11.00 │6.00 │6.00 Chlorine liberation (m) │ 0.80 │ 0.70 │0.85 │0.71 —————————————————————————————————┴————————┴————————┴——————┴——————

Several points of interest are to be noted in the above table, the first and most conspicuous of which is the fact that the saliva did not act at all upon the raw flour and raw wheat, as shown by the total absence of maltose in the cases represented in columns 3 and 4. The small amount of dextrine and soluble starch shown was, perhaps, already present in the raw grain, but this point I have not investigated. It is clear, however, that no sugar was produced when raw starch was taken, whereas the amount of sugar produced after the ordinary test meal was more than 1 gram in each 100 c.c. of stomach fluid; in other words, the stomach fluid contained more than one per cent of sugar without taking into account the amount which had been absorbed.

The figures for maltose in column 2 represent a test meal in which little or no saliva was mixed with the test meal, the food being swallowed without chewing, indicating very slight action of the saliva, the amount of maltose found in the stomach fluid being but a trifle more than one-fourth the amount obtained after an ordinary test meal. The amount of soluble starch and dextrine was less than half the normal amount in the case of the raw flour, and but little more in the case of the raw wheat.

Another point of interest is the increased amount of lactic acid found in the test meal taken without chewing, represented in column 2. The coefficient of fermentation which represents the number of milligrams of lactic acid (as expressed in terms of HCl) found in 100 c.c. of stomach fluid was more than double that found after the same kind of test breakfast properly masticated, represented in column 1. The results of this experiment distinctly associate acid fermentation with imperfect mastication and imperfect salivary digestion.

Another fact noted in a comparative study of the results of the analysis of over 5000 stomach fluids, which very strongly confirms this idea, is that starch conversion is usually complete in cases of apepsia, while lactic acid is conspicuous by its absence. In nearly all cases of apepsia which I have encountered, numbering about forty cases in all, the most delicate tests for lactic acid have failed to show its presence except in the most minute quantities; in most cases it was entirely absent.

There are a number of other points of interest in the above table in addition to those which relate particularly to starch digestion. One of the most noteworthy of these is the fact that the digestion of albumen was not unfavourably influenced by the neglect to masticate the food, the coefficient of digestion, in fact, being raised from .82 to .97. This coefficient is a qualitative and not a quantitative index. The higher coefficient indicates a more perfect elaboration of proteids and a close approach to an absolutely perfect proteid digestion.

Another fact of perhaps even greater interest has relation to the digestion of albumen when the wheat was eaten raw, in the form of either flour or wheat. The coefficient of proteid digestion in both cases, as shown in columns 3 and 4, was 1.00, indicating perfect elaboration of the albuminoids. From this it appears that raw gluten, or the proteids of wheat, is digested more perfectly when taken in a raw state than when cooked, the very opposite of which we have seen to be true of starch. The digestion of raw starch may take place in the intestines, by the action of the pancreatic juice, but cannot take place in the stomach, for the reason that the saliva has not the power to penetrate the cellulose envelope of the starch granule, and hence cannot digest raw starch.

This fact coincides in a most interesting manner with the biological fact that man is by nature a frugivorous animal. In the process of ripening, the starch of fruits undergoes a hydration similar to that which takes place in cooking and in pancreatic digestion, whereby the insoluble starch is converted into soluble starch, dextrine, and sugar. This explains, also, why well-ripened fruit may be eaten raw with impunity, while unripe fruit and farinaceous food of all sorts require cooking. In his diet, man, like his nearest relative, the monkey, being naturally a frugivorous animal, may eat fruits in the state in which Nature has provided them; but when he introduces other natural products into his bill of fare, he must adopt artificial means for securing the preparation for digestion which Nature makes in the ripening process of fruits.

The coefficient of chlorine liberation (m) is very nearly uniform, indicating that the mastication of food and the cooking of food have little influence upon this digestive function.

The coefficient of salivary activity (c) was determined independently for each test breakfast. Its practical uniformity indicates that there was no essential change in the character or quality of the saliva to account for the differences shown by the totals in relation to the stomach digestion of starch.

DR. EDWARD HOOKER DEWEY AND THE “NO BREAKFAST PLAN”

The “No Breakfast Plan,” evolved from the long experimental experience of Dr. Dewey, to secure much needed rest for the stomach and intestines, is described in a book bearing that title which can be had direct from the author by addressing him at his home, Meadville, Penn., U. S. A.

“No Breakfast” is, evidently, a misnomer, but means, in the present application, an appetite earned after arising from sleep. The writer, for instance, often begins work so early in the morning that by the time the ordinary breakfast is ready he has already done a fair day’s work.

The writer has no reported details of the work of Dr. Dewey to add to this volume. In “Glutton or Epicure” full appreciation of this Esculapian Luther is expressed and extracts of his writings are reprinted. In fighting for more than forty years for the principle of less abuse of the tired body of man, Dr. Dewey has rendered a service that some time will be reckoned very great; and while there is no scientific report of the good doctor’s work to call for introductory comment, it would be equally unhealthy to miss an opportunity to express gratitude for what he has done for us all.

PROFESSOR JAFFA AND THE FRUITARIANS

Professor Jaffa, too, of the University of California, has been doing most valuable service in testing the usefulness of fruits and nuts as human foods. He generously furnished the author with elaborate tables of his results, covering several years of observation, showing low nitrogen possibilities similar to those demonstrated by the writer and his colleagues at Cambridge and Yale. These have since been published, and relating to special kinds of foods, as they do, suggest a wide range of choice among the fruits of earth; but the collected evidence of this book shows that human nutrition is best served when the appetite, being kept at normal, is allowed to make selection from the whole range of nutritious products furnished by good Mother Nature.

DR. H. P. ARMSBY

In the Oct. 16th, 1903, number of Science, also, is an interesting article by Dr. H. P. Armsby on the heat values and muscular energy values of different food elements and their isodynamic replacement of each other under various conditions.—HORACE FLETCHER.]

Explanation of The A. B. C. Life Series

THE ESSENTIALS AND SEQUENCE IN LIFE

It would seem a considerable departure from the study of menticulture as advised in the author’s book, “Menticulture,” to jump at once to an investigation of the physiology and psychology of nutrition of the body and then over to the department of infant and child care and education as pursued in the crêche and in the kindergarden; but as a matter of fact, if study of the causation of human disabilities and misfortunes is attempted at all, the quest leads naturally into all the departments of human interest, and first into these primary departments.

The object of this statement is to link up the different publications of the writer into a chain of consistent suggestions intended to make life a more simple and agreeable problem than many of us too indifferent or otherwise inefficient and bad fellow-citizens make of it.

It is not an altogether unselfish effort on the part of the author of the A. B. C. Life Series to publish his findings. In the consideration of his own mental and physical happiness it is impossible to leave out environment, and all the units of humanity who inhabit the world are part of his and of each other’s environment.

It would be rank presumption for any person, even though gifted with the means to circulate his suggestions as widely as possible, and armed with the power to compel the reading of his publications, to think that any suggestions of his could influence any considerable number of his fellow-citizens of the world, or even of his own immediate neighbourhood, to accept or follow his advice relative to the management of their lives and of their communal and national affairs; but while the general and complete good of humanity should be aimed at in all publications, one’s immediate neighbours and friends come first, and the wave of influence spreads according to the effectiveness of the ideas suggested in doing good; that is, in altering the point of view and conduct of people so as to make them a better sympathetic environment.

For instance, the children of your neighbours are likely to be the playmates of your own children, and the children of degenerate parents in the slum district of your city will possibly be the fellow-citizen partners of your own family. Again, when it is known that right or wrong nutrition of the body is the most important agent in forming character, in establishing predisposition to temperance or intemperance of living, including the desire for intoxicating stimulants, it is revealed to one that right nutrition of the community as a whole is an important factor in his own environment, as is self-care in the case of his own nourishment.

The moment a student of every-day philosophy starts the study of problems from the A. B. C. beginning of things, and to shape his study according to an A. B. C. sequence, each cause of inharmony is at once traced back to its first expression in himself and then to causes influenced by his environments.

If we find that the largest influences for good or bad originate with the right or wrong instruction of children during the home training or kindergarden period of their development, and that a dollar expended for education at that time is worth more for good than whole bancs of courts and whole armies of police to correct the effect of bad training and bad character later in life, it is quite logical to help promote the spread of the kindergarden or the kindergarden idea to include all of the children born into the world, and to furnish mothers and kindergarden teachers with knowledge relative to the right nutrition of their wards which they can themselves understand and can teach effectively to children.

If we also find that the influence of the kindergarden upon the parents of the infants is more potent than any other which can be brought to bear upon them, we see clearly that the way to secure the widest reform in the most thorough manner is to concentrate attention upon the kindergarden phase of education, advocate its extension to include even the last one of the children, beginning with the most needy first, and extending the care outward from the centre of worst neglect to finally reach the whole.

Experience in child saving so-called, and in child education on the kindergarden principle, has taught the cheapest and the most profitable way to insure an environment of good neighbours and profit-earning citizens; and investigation into the problem of human alimentation shows that a knowledge of the elements of an economic nutrition is the first essential of a family or school training; and also that this is most impressive when taught during the first ten years of life.

One cannot completely succeed in the study of menticulture from its A. B. C. beginning and in A. B. C. sequence without appreciation of the interrelation of the physical and the mental, the personal and the social, in attaining a complete mastery of the subject.

The author of the A. B. C. Life Series has pursued his study of the philosophy of life in experiences which have covered a great variety of occupations in many different parts of the world and among peoples of many different nations and races. His first book, “Menticulture,” dealt with purging the mind and habits of sundry weaknesses and deterrents which have possession of people in general in some degree. He recognised the depressing effect of anger and worry and other phases of fearthought. In the book “Happiness,” which followed next in order, fearthought was shown to be the unprofitable element of forethought. The influence of environment on each individual was revealed as an important factor of happiness, or the reverse, by means of an accidental encounter with a neglected waif in the busy streets of Chicago during a period of intense national excitement incident to the war with Spain, and this led to the publication of “That Last Waif; or, Social Quarantine.” During the time that this last book was being written, attention to the importance of right nutrition was invited by personal disabilities, and the experiments described in “Glutton or Epicure; or, Economic Nutrition” were begun and have continued until now.

In the study of the latter, but most important factor in profitable living, circumstances have greatly favoured the author, as related in his latest book, “The A. B.-Z. of Our Own Nutrition.”

The almost phenomenal circulation of “Menticulture” for a book of its kind, and a somewhat smaller interest in the books on nutrition and the appeal for better care of the waifs of society, showed that most persons wished, like the author, to find a short cut to happiness by means of indifference to environment, both internal and external, while habitually sinning against the physiological dietetic requirements of Nature. In smothering worry and guarding against anger the psychic assistance of digestion was stimulated and some better results were thereby obtained, but not the best attainable results.

Living is easy and life may be made constantly happy by beginning right; and the right beginning is none other than the careful feeding of the body. This done there is an enormous reserve of energy, a naturally optimistic train of thought, a charitable attitude towards everybody, and a loving appreciation of everything that God has made. Morbidity of temperament will disappear from an organism that is economically and rightly nourished, and death will cease to have any terrors for such; and as fear of death is the worst depressant known, many of the worries of existence take their everlasting flight from the atmosphere of the rightly nourished.

The wide interest now prevalent in the subjects treated in The A. B. C. Life Series is evidenced by the scientific, military, and lay activity in connection with the experiments at the Sheffield Scientific School of Yale University and elsewhere, as related in the “A. B.-Z. of Our Own Nutrition” and in “The New Glutton or Epicure” of the series.

The general application is more fully shown, however, by the indorsement of the great Battle Creek Sanitarium, which practically studies all phases of the subject, from health conservation and child saving to general missionary work in social reform.

HORACE FLETCHER.

Index

A. B. C. Life Series, the, xxiv, 15, 47; explanation of, 399-407

Abdominal glands, the, 189, 190

—— muscles, the, 326, 388

—— wall, the, 364

Abernethy biscuit, 131

Acid reaction, of food, 269

Acids, stimulating properties of, 270; supplement weak action in the stomach, 270; special relation to the pancreas of, 270

Addison, Joseph, upon the work of Luigi Cornaro, 28

Adenoids, largely dietetic in origin, 148-152, 156

Afferent nerves, special duty of the peripheral terminations of, 184-185

Agriculture, U. S. Department of, 37

Albumen, digestion of, 394

Albuminoids, the, 395

Albuminous foods, minimum amount of, 74, 78

Alcoholic beverages, explanation of the use of, 252

Algarroba bean, the, 124

Alimentary canal, the, 13, 14, 15, 40; pabulum derived from, 40, 92, 117; Professor Pawlow’s conclusions concerning, 186; experimental investigation of the pathology and therapeutics of, 248, 260, 273, 275, 276, 277

Alimentation, human, study of, 13; theory of, 180

Alkalies, the, 278, 279, 280, 281, 282

Alkaline reduction, 33, 34, 35, 36, 44

—— saliva, 33; its quantity increased by mastication, 96, 102, 146

Alkalinisation, 92

Altruism, placed upon a business basis, xxiv

American Medical Missionary Association, the, 390

—— Medical Missionary Cause, the, xxiii

—— Physiological Society, the, 68

Anderson, Dr. William G., 54, 87, 88

Anger, causes indigestion, 7

Animal economy, 40

—— food, necessitates less thorough mastication than vegetable, 67, 99-100, 173; influenced less than vegetable by cooking, 118

—— organism, the efficiency of, 58

Anthropoid apes, 115, 116

Antiperistalsis, 326, 333, 342, 345, 364; in the colon, 365-370; the question of, 377-383, 384, 385, 387, 388

Antiperistaltic waves, 365, 367, 373, 374, 376, 381, 383, 387, 388

Antrum, the, 307, 308, 311, 315, 322, 323, 326, 327, 333, 334, 336, 340, 341, 360

Apepsia, 394

Appendicitis, relationship between diet and, 141

Appendix, the, cause of catarrh of, 141

Appetite, demands proteid when wanted, xxxii; knows what to do and when to do it, xxxiii; most important factor in digestion, 6; a perfect indicator, 6; a creature of the mind, 7; the caprices of, 7; easily comprehended, how to read, 8, 9, 12; an indicator of what the body requires, 20; will close the valve when enough is eaten, 20; striking effect of insalivation upon, 50; fully understood, prevents intemperance in eating or drinking, 95; sooner satisfied with thorough mastication, 137; the first and mightiest exciter of the secretory nerves of the stomach, 210; is juice, 213; Dr. Pawlow’s experiment showing value of, 226; its initial impulse may originate in the stomach, 244; in the rich and in the poor, 252-253; care should be taken of, 254; physicians most often called on to restore, 254; remarkable how little attention is paid to, 255; bitters increase, 263, 265; the strongest of all stimuli to the digestive glands, 263; connection between gastric juice and, 265.

—— earned, a preliminary necessity of easy digestion, 180

——, false, 6, 9, 29, 75

——, normal, 6

“Appetite juice,” the, 213, 228, 258, 259, 260

Apples, 169

Appreciation, attention necessary to create, 7; necessary to stimulate flow of digestive juices, 7, 12

Armsby, Dr. H. P., on the heat values and muscular energy values of different food elements, 397

Asiatics, the, consume smaller proportion of proteids, 82

Asparagus, 93

Astrup, E., 126

Athletes, reason for training, 22

Attention, necessary to create appreciation, 7; how to command, 8, 9, 12

Atwater, Prof. W. O., 54; on the daily proteid requirement, 76

—— Respiration Apparatus, the, 57

Australians, the, 118, 129, 163

Bache Fund, the, 69

Bacteria, the action in the intestines of, 39, 117

Bacterial digestion, 40

—— flora, the, examination of, 26

Bacteriology, advances of, 248, 249

Bailey, 128

Balthazard, experiments of, 314, 315, 327, 328

Baltimore, Md., 68

Barling, Gilbert, 141

Barrett, Robert, 47

Bayliss, experiments of, 343, 344, 345, 359

Batter pudding, 98

Battle Creek, Michigan, 390

—— Laboratories, the, 389-391; experimental investigation of the influence of mastication and cooking of food, etc., in, 391-396

—— Sanitarium, the, xvii, xxiii, xxvii; described, 389-391

Bayert, 123

Beans, 95, 132

Beaumont, experiments of, 305, 309, 310, 313, 326, 327, 329, 330, 334, 336

Beef, 100

Benedict, Prof. Francis G., 54

Berlin, 56, 65

Berne, Switzerland, 284

Betel, chewing, 103, 128

Beverages, mastication in the preparation of, 123

Bidder and Schmidt, experiments of, 202, 204, 231; conditions for success, 204-206

Bile, the, 360

Bitters, therapeutic influence of, 262, 265; increase the appetite, 263, 264, 265

Blondlot, experiments of, 181, 182, 277

Blood, the, toxins absorbed into, 40; influence of the contraction of the masticatory muscles on local circulation of, 107, 148, 149, 278, 355

—— elements, the, 41

Blumfield, Dr. Joseph, 26

Body, the, considered as an engine, 4, 23; derives its necessary energy from food, 72; burdened by excess of food, 73

Boer War, the, 11

Bolting food, 35, 36, 134, 135, 138, 140

Bolus, the, 329, 343, 344

Boston Society of Medical Sciences, the, 342

Bouillon, 266

Bowditch, Dr. Prof. Henry Pickering, xxiv, xxv, 67, 68, 70, 284, 285, 287, 306

Bowel, the, liable to suffer, 140, 345

“Bracer,” a, why required, 20

Braun and Grützner, experiments of, 278

Bread, 78, 98, 99, 132, 137, 143, 171, 270, 271, 274, 275

Brinton, experiments of, 329, 330, 334, 336

British Guiana, 124

—— Medical Association, the, 27, 48, 91, 92

“British Medical Journal,” the, 141

Bronchitis, 144, 146

Broth, strong, 268

Brown bread, 43

Brussels, 68

Buccal digestion, 8

—— nerves, the, 194

Bushmen, the, 118, 123

Butter, 43, 100

Cabbage, why indigestible, 99

Cæcum, the, 140, 141, 363, 364, 365, 366, 368, 370, 371, 372, 375, 376, 377, 381, 387

Cake, 132

California, University of, 90, 397

Calm, easy to cultivate, 7

Cambridge, England, xxxi, 26, 47, 49

—— tests, the, 47, 69

—— University, England, xxv, 26, 53, 68, 91

Campbell, Dr. Harry, 8, 12; on the importance of mastication, 92-179, 389

Cancer, produced by inefficient mastication, 138

Cane-sugar, changed to grape-sugar, 21, 169

Cannon, Dr. W. B., 7, 12; on “Swallowing and Movements of the Stomach and Intestines,” 284-300; on the “Movements of the Stomach Studied by means of the Röntgen Rays,” 301-341; on the “Movements of the Intestines Studied by Means of the Röntgen Rays,” 342-388

Carbohydrate foods, 78, 79, 80, 85, 86, 89

Cardia, the, ideas of early writers concerning, 303, 304, 325, 326, 328, 329

Cardiac sphincter, the, 307

Carelessness, the sin of, xvii

Carnegie, Andrew, xxxv

—— Institution, the, 53

Carnivora, the, do not masticate, 97, 161

Cassava root, 124

Cat, the, experiments upon, 289-293, 299, 303, 307, 311, 312, 315, 320, 322, 325, 333, 335, 337-339, 341, 344, 353, 359, 361, 365, 366, 372, 382, 383-386, 388

Catarrh of the appendix, caused by inefficient mastication, 141

Cauliflower, 99

“Cause and Prevention of Decay in Teeth, the,” Wallace’s, 161

Cavendish lecture, Sir Frederick Treves’s, 140

Cell, a, determination of the metabolism of, 40

Cellulose, 117, 170

Cereals, 78, 84, 146

Ceylon, 128

Cheese, 43, 95; when indigestible, 100, 137

Chemical excitants, the, 268

—— secretion, 259

Chemistry, organic, 62

——, physical, 62

Chewing, length of time necessary for, xxxii

Chicken bone, 166

Chigin, Dr., experiments by, 214, 216, 282

Children, early feeding of, 130-132, 143; defective mastication in, 148; feeding of, 262

Children’s Aid Society, the, xxv, 68

Chimpanzee, the, 115

China, 82

Chittenden, Prof. R. H., conducting the experiments at Yale, xvii, 5; emphasises the want of exact knowledge of nutrition, 53, 67, 68; the Yale test, 69-91.

Chop bone, 166

Chyme, the, 346, 360, 362

Circulation, the, stimulated by mastication, 96, 103, 157

Cocoa-nut, 137

Coffee, 132

Cole, Sidney W., 47; his paper upon the isolation of the tryptophane element of the proteid molecule, 47

Colon, the, 363, 364; antiperistalsis in, 365-370; changes when food enters, 370, 371, 372; process of clearing, 373-377, 381, 382, 384, 387, 388

Comminution, 98, 100, 101

Commonwealth, the S. S., 69

Condiments, influence of, 261, 265

Constipation, cannot exist, 43

Constriction, waves of, 323, 340, 341

Cooked flesh, requires mastication, 97, 174

Cooking, influences vegetable more than mineral food, 118; effect of, 389, 391-396

Cornaro, Luigi, reformed manner of living of, ix; his autobiography, x, xvi, xvii; Dr. Van Someren’s paper upon his theory of living, 26-46; his treatise on the “Sure and

Certain Method of Attaining a Long and Healthful Life,” 28; Addison’s comments upon his work, 28, 92

Craving for food, 256

Cream, experiments with, 38-39, 43

Cuba, xiv, 70

Curr, E. M., 125, 129

Dastre, Dr. Prof. A., 67, 68

Day, experiments of, 337

Defecation, 373-377

Deglutition, Magendie’s theory of, 284, 285; movements of, 285; divided into three parts, 285; Falk’s and Kronecker’s theory of, 286; the X-ray method in the study of, 287-295; phenomena of œsophageal, 298-300

—— reflex, the, 287

Dental caries, causation of, 161

Dewey, Dr. Edward Hooker, and the “No Breakfast Plan,” 396, 397

De Witt, Assistant Surgeon, Lieut. Wallace, in command of soldiers in the Yale investigation, xiii, 70

Dextrine, 170, 171, 392, 393, 395

Diaphragm, the, 324, 326

Diet, best manner and system of, xiii; the optimum, xxxi; minimum, 74; the anthropoid stage, 116; the pre-cooking human stage, 117; the pre-agricultural cooking period, 118; the early agricultural age, 119; the late agricultural period, 120; for children, 130-132; relationship between appendicitis and, 141

Dietary Ten Commandments, 5

Dietetics, precepts of, 272

Digestion, appetite the most important factor in, 6; the true chemical end-point of, 10-11; effect of the mental state upon, 74, 145; psychic influence in, 180; the phenomena in, 251; thorough mouth-work as an aid to, 389

Digestion-ash, the, what it should be like, 10-11, 14; should not be unclean, 24; in experiments, 38-39, 42, 43, 47, 51, 79, 83, 84, 85, 94

Digestive activity, stopped by anger and worry, 7

—— canal, the. See Alimentary canal, the

—— glands, the, analogy between the innervation mechanism of the salivary glands and, 188-190; appetite the strongest of all stimuli to, 263, 280, 282

—— juices, the, 7; appreciation necessary to stimulate flow of, 7, 12, 96; mastication brings the food into intimate contact with, 98; quantity of, 267; relation of milk to the secretion of, 274, 383, 386

Digitalis, 281

Diphtheria, 149

Disease, caused by indiscretions in eating, x, xxxi; follows disobedience, 29

Disobedience, disease follows, 29

Distention, 144

Distress, effect of, 388

Dog, the experiments upon, 181, 194-211, 212-246, 249, 254, 258, 263, 279, 280, 285, 292, 293, 297, 298, 299, 303, 310, 311, 313, 314, 315, 336, 344

Dolomites, the, 26

Drinking, too much, xix, 95

Dry food, 97

Dunn, Miss Eva, 122

Duodenum, the, 303, 315, 356, 360

Dyspepsia, dangers of, xv; might cease to exist, 35

Eat, how to, 19

Eating, too much, ix; indiscretions of, x, xix, xxix, 29, 95, 135; too fast, 20; systematic inattention to, 259, 260; English have made a cult of, 261

Economic nutrition. See Nutrition, economic

Efferent nerves, 184, 185

Efficiency, human, the measure of, xxx; research into causes for, 54

Eggs, experiments with, 38, 43, 78, 95, 100, 137, 277

“Encyclopædia Britannica,” the, 27

Enemata, the, 367, 379, 380, 388

Energy, the minimum transformation of, 59

——, potential, 59

Engine, an, the body considered as, 4, 23

English, the, have made a cult of the art of eating, 261

Emetic, an, 325

Emotion, inhibition of stomach movements during, 337; effect of, 383-384, 388

Empiricism, medical practice largely based upon, 52

Esquimaux, the, 118, 123, 125, 126

Esselmont, experiments of, 383

Evolution, Nature’s plan of, xi

Ewald, experiments of, 313, 314

Excess, habitual, confirmed by experiments, ix

Excrements. See Digestion-ash, the

Excretia. See Digestion-ash, the

Exercise, necessity of, xxix

Fæces, the, 374. See also Digestion-ash

Falk, Dr., 284; theory of deglutition of, 286

Fallopius, on the functions of the stomach, 302

Farinaceous food, 395

Fasola, experiments of, 378

Fat, potatoes need not produce, 21, 78, 79, 80, 85, 86, 95, 98, 100; experiments upon, 271, 272, 274

Faucial tonsils, the, influence of mastication upon, 148

Fear, effect of, 388

Fearthought, 404

Featherman, 123

Fibrin, 276

Flesh food, reduction of craving for, 50

Fletcher, Horace, Dr. Van Someren’s comments upon the case of, 30-31; his experiments confirmed by Marckwald, 46; Sir Michael Foster’s comments, 48; the Cambridge tests, 49-52; the Middletown test, 54-55, 60; the Yale test, 75-91

Flour, 132, 392, 393, 395

Food, mal-assimilation of, x; length of time for chewing, xxxii; Dr. Kellogg’s estimate of amount habitually used, xxxiv; mouth-treatment of, 5; how to masticate and swallow, 8, 9, 31, 32; actual process of mastication described, 32-34; important bearing upon the economy of the body of its treatment in the mouth, 48-49; its function to supply material from which the body derives necessary energy, 72; any excess an incubus, 72-73; classified under three heads, 78; in excess, produces a large amount of unnecessary work, 80; its nutritive value determined by the thoroughness of its digestion, 79; softness of, 129; mastication tends to reduce amount of, 136; should be eaten with interest and enjoyment, 252; passionate craving for, 256; its nutritive value should be considered rather than taste, 261; the acid reaction of, 269; relative nutritive values of different, 275, 276; experiments upon the utilisation of, 275; effect of the movements of the stomach upon, 328; circulation of, 329; experimental investigation of the influence of mastication and cooking of, 389-396

Foster, Sir Michael, xxiv, xxv, 26; his note upon Dr. Van Someren’s paper, 48-52; emphasises the want of exact knowledge of nutrition, 52, 53, 67, 68, 91

Fowls, experiments upon, 299

Fruitarians, the, 90, 397

Fruit sugar, 169

Fruits, 43; under-ripe and over-ripe, 141, 395, 396; usefulness of, 397

Fubini, experiments of, 383

Fundus, the, 317, 322, 323, 324, 325, 330, 333, 334, 335, 336, 337, 340

Galen, on the functions of the stomach, 302

Gastric catarrh, 249

—— digestion, 309, 316

—— glands, the, 182; the vagus and the sympathetic nerves exciters of, 183, 198; mechanical and chemical stimulation of the cavity of the mouth has no effect on, 201; psychic excitation of, 205; sleep exercises no restraining influence upon, 206; the simultaneous excitation of the different sense organs the first and strongest impulse toward activity of, 210; psychic secretion the normal commencement of secretory activity on the part of, 214; conditions upon which depends the secretory work of, 227; mechanical stimulation of, 237, 245, 249, 271, 272, 274, 280

Gastric juice, the, appreciation necessary to stimulate flow of, 7; destroys micro-organisms, 41; its flow increased by mastication, 102, 146; secretion of, 181, 206, 208, 211, 213, 262; connection between the appetite and, 265, 266; experiments for, 267; too little, 270, 272, 273; salts of sodium promote a flow of, 277, 279, 280, 329, 334, 335, 337, 340, 341

—— mechanism, the, 385

—— movements, the, 301; early writings on subject of, 302; later experiments upon, 303, 327, 329, 338

—— mucous membrane, the, excitability of, 181, 231, 241, 249, 258, 259, 264

—— muscular fibres, the, 307

“Gastric tonics,” 255

Gastritis, inefficient mastication may produce, 138

Gastro-intestinal catarrh, 144

Gastronomic enjoyment, increased by proper mastication and insalivation, 22

Germany, food in, 267

Ginger, preserved, 141

Gladstone, William E., his theory of mastication, 92

Gland metabolism, 277

Glinski, Dr., 190, 194, 196, 197

Gluten, raw, 395

“Glutton or Epicure,” 26, 31, 92, 389, 396. See also “New Glutton or Epicure, The”

Goose, the, experiments upon, 288

Goose-fat, 100

Gorilla, the, 115

Gran Chaco Indians, the, 123

Grape-sugar, chemically made from cane-sugar, 21, 169

Greens, 132

Grey, Sir George, 128

Griddle-cakes, need not be hurtful, 21

Griffin, Charles & Company, 180, 181

Grützner, experiments of, 278, 346, 363, 377, 378, 381

Gscheidlen, 235

Guinea-pigs, experiments upon, 39

Gum arabic, chewing, 103

Gustatory indifference, 263

—— nerves, the, 263, 269

Gut, the, 344, 345, 355, 360, 364, 365, 374

Hæmorrhoids, cannot exist, 43

Haller, experiments of, 304; his summary of the motor functions of the stomach, 304-305, 309

Harvard Medical School, 68

—— Physiological Laboratory, the, 284

Haste, danger of, 134-135

Headache, produced by inefficient mastication, 138

Health, the optimum, xxxi

Hearing, the sense of, 210

Heart, the, stimulated by mastication, 96, 103, 281

Heartburn, 144

Heat values, 397

Heger, Dr. Prof. Paul, 67, 68

Heidenhain, 181, 182, 183, 235

Herbivora, the, practice thorough mastication, 97

Higgins, Dr. Hubert, letter from, xxvii-xxxiii, 47

Hirsch, experiments of, 305, 315

Hofmeister, experiments of, 305, 308, 309, 310, 311, 313, 314, 326, 327, 332

Hopkins, Dr. F. Gowland, 26; his paper upon the isolation of the tryptophane element of the proteid molecule, 47

Hors d’œuvre, 266

Horse, the, experiments upon, 293, 294, 300

Hospital Corps, the, at New Haven, xiii, 70

Hunger, 241; “the best sauce,” 254

Hyperacidity, 145

Hyperæmia, 345

Hyperchlorhydria, 144, 147

“Igniting juice,” 260

Ignorance, dietic, sin of, xvii

Ileocæcal valve, the, 355, 362; the competence of, 362-364, 367, 370, 376, 381, 387, 388

Ileum, the, 363, 364, 367, 370, 382, 387

India, 82, 128

Indians of Honduras, the, 124

—— of Nicaragua, the, 124

—— of North California, the, 122, 126

Indigestion, x; dangers of, xv; caused by anger and worry, 7; “bunching hits” to oppose, 13-16

Indol, the odourous, 47

Industries, the, mastication in, 124

Infant life, action of saliva in, 36

Innervation mechanism, an, constituent parts of, 184

Insalivation, defined, 8, 22; increases gastronomic enjoyment, 22, 46, 48; its striking effect upon appetite, 50, 60; effects of, 74, 89, 92, 93, 96; mastication promotes, 101

Insane, the, forced feeding of, 268

Instinct, human, the outcome of every-day experience, 251; physiology merely confirms the precepts of, 251; provisions for digestion made by, 267; demands of, 272

Intemperance, 95

International Congress of Physiologists, the, 26, 48, 56, 68, 91

—— Laboratory of Research, the, proposal to found, 55-69; suggestions as to staff and personnel, 62; estimate of initial outlay, 63; suggestions as to location, 63; suggestions as to management, 66

Intestinal anæmia, 345

—— canal, the, 39, 346

—— contents, the, rhythmic segmentation of, 347-355, 386

—— digestive juices, the, 361

—— mechanism, the, 385

—— movements, difficulties of investigating, 342; the best known of, 343

—— secretion, 61

—— wall, the, 344, 381, 386

Intestine, the large, activity of, 343; movements of, 364-377, 379, 386, 387, 388

——, the small, 343, 346; the movements of, 347-362, 366; course of food in, 360-362, 365, 367, 369, 378, 381, 383, 385, 386, 387, 388

——, the, action of the bacteria in, 39; micro-organic action in, 40, 80, 92; much more sensitive than the stomach, 139, 301, 317, 328, 337, 341; studied by means of the Röntgen rays, 342-388, 395

Jaffa, Professor, 90; and the fruitarians, 397

Japan, 82

Jaws, the, mastication stimulates the nutrition of, 96, 103, 155; influence of mastication upon, 109, 148; changes during man’s evolution in, 115-121; instances of vigorous use, 122

Johns Hopkins University, 68

“Journal of Physiology, The” (American), 284, 301, 342

—— (English), 47

Kais Root, 123

Kane, Dr., 125

Kara, 124

Katabolic action, 41

Katabolism, 95

Kellogg, Dr. J. H., xxvii; letter from, xxxiii-xxxv; his estimate of amount of food habitually used, xxxiv; tribute to, 391; his experimental investigation of the influence of mastication and cooking of food, 391-396

—— Mrs. J. H., 389; tribute to, 391

Kelp, 122

Kotljar, experiment by, 217

Kreuznach, 46

Kronecker, Dr. Prof. Hugo, 67, 68, 284, 285; theory of deglutition of, 286

Kumagawa, experiments of, 81

Kwas, 267, 269, 270

Lactic acid, prepared in the stomach, 269, 393, 394

“Lancet, The,” 8, 26, 31; Dr. Campbell’s articles from, 92-179, 145

Lard, 272

Laws of Nature, health, strength, and moral tone dependent upon proper fulfilment of, 73

Leonardi, Dr. Professor, 26

Life, right conduct of, xiii; the essentials and sequence in, 399

Lippincott, J. B. & Company, 180, 181

Liqueurs, 266

Liquids, how to treat, 9, 34, 93, 94, 95

Lobassoff, Dr., experiments by, 217, 218, 220, 222, 226

Lobster, 137, 141

London, 65

Lower Californians, the, 123

Ludwig, experiments of, 342

Lumen, the, 374

Lymph, influence of the contraction of the masticatory muscles on local circulation of, 107, 148, 149, 355

Macaroni, 132

—— cheese, 100

Mackerel, 141

Madrid, 69

Magendie, theory of deglutition of, 284

Maize, chewed, 124

Mal-assimilation, of nutriment, x, xxi; “bunching bits” to oppose, 13-16; dangers of, 24, 35

Malay, 128

Mall, experiments of, 343, 345, 354, 378

Mal-nutrition, causes of, xxi, 35

“Malt extracts,” 102

Maltose, starch turned into, 101, 170, 392, 393

Man, the First Assistant of Nature, xi; his disparity due to ignorance, xii; absurdity of his ignorance, 4, 23; experiments upon, 300; by nature a frugivorous animal, 395

Maple sugar, 84

Marckwald, Max, paper “On Digestion of Milk in the Stomach of Full-grown Dogs,” 46

Masticate, how to, 19

Mastication, inefficient, causation of, 129; must lead to many evils, 129; evils resulting from, 135; conduces to excessive eating, 135; may cause suffocation, 137; may produce gastritis, 138; excess of starch may pass into stomach because of, 141; prevents a sufficient amount of alkali to pass into the stomach, 146; causes evils with the jaws and their appendages and the adjacent structures, 148; responsible for adenoids, 148-152; a potent cause of Rigg’s disease, 159; secondary evils of, 164, 394

——, proper, increases gastronomic enjoyment, 22, 46, 48, 60; effects of, 74, 89; Dr. Campbell’s observations upon, 96-173; the effects of, 96; primary object of, 96; promotes flow of saliva, 96, 101; stimulates the heart and circulation, 96, 103; influences the nutrition of the jaws, 96, 103; facilitates swallowing, 97; brings the food into intimate contact with the digestive juices, 98; increases amount of alkaline saliva passing into the stomach, 96, 102; acts reflexly upon the stomach, 102; the muscles of, 104; its influence upon the jaw-bones, 109; its influence upon the teeth, 110; in the preparation of beverages, 123; in the industries, 124; the instinct of, 126; the causation of inefficient, 129; less opportunity than formerly for, 130-133; defective apparatus for, 133; affected by individual differences, 134; tends to diminish amount of food consumed, 136; most effective way to secure starch digestion, 145; effect upon the nasal passages, naso-pharynx, and faucial tonsils, 148; fast becoming a lost art, 157; means of insuring adequate, 164, 389; experimental investigation of the influence of, 391

Masticatory instinct, the, 126-129

—— muscles, the, 104; influence of their contraction on local circulation of blood and lymph, 107, 148

Matri, 128

Meadville, Penn., 396

Measles, 149

Meat, 78

—— broth, 266; an important chemical excitant of gastric secretion, 266, 267

—— extract, 268

—— juice, 268

Mechanical stimulus, great importance assigned to, 257

Medical practice, largely based upon empiricism, 52

—— science, not possessed of final information concerning questions of nutrition, 52

Medicine, ideal only when it can take its proper position, 249; physiology can make no pretence to guide the field of, 251; to what it will at length grow, 251; treats too lightly the loss of appetite, 256

Melanesia, 128

Melanesians, the, 120

Meltzer, Dr., 284; experiments of, 294, 296, 297, 298

Mendel, Dr. Lafayette B., 69

Mendel Pass, bei Bozen, Süd Tirol, Austria, experiments at, 26

Mental energy, 41

—— state, 12; its effect upon digestion and nutrition, 74

Menticulture, physical and mental equipments necessary to promote, 7

“Menticulture,” xxi, xxiv

Metabolism, 37; determination of, 40; calorimetric trial-balance measurement of, 54

Micro-organisms, 40; destroyed by acid gastric juices, 41

Middletown, Conn., experiments at, 54

Milk, how to drink, 9; experiments in drinking, 36, 38-39, 78, 84, 93, 94, 268; takes a special position among foods, 272; the three properties of, 273; its relation to the secretion of the digestive juices, 274, 275, 276, 277

—— pudding, 97, 143, 172

“Modern Medicine,” 389, 391

Modoc Indians, the, 123

Moist foods, 97

Moritz, experiments of, 324, 328, 332

Mosso, Dr. Prof. Angelo, 67, 68, 284, 285

Mouth, the, should do all it can, 93, 180; examination of, 174-179; rinsing, 179; mechanical and chemical stimulation of the cavity of, 201, 285, 286

—— breathing, evils of, 151-153

—— discrimination, 94

—— thoroughness, 8

—— treatment, of food, 5, 12, 92; a preliminary necessity of easy digestion, 180, 389

Mucosa, the, 343, 355

Mucous membrane, the, 346

Munich, 56, 76, 81

Muster, 128

Mutton, 100

Nansen, J. F., 123 Napoleon, died from fast eating, 138

Nasal passages, the, effect of mastication upon, 148

Naso-pharyngitis, 144, 148, 149

Naso-pharynx, the, influence of mastication upon, 148

National Academy of Sciences, the, contribute to fund for research, 69

Natural Automatic Processes, 3, 180

Nature, plan of evolution of, xi; Man the First Assistant of, xi; her reward for conformity with her requirements, xii; her generous assumption of forty-seven forty-eighths of labour, 5, 12; given an opportunity by economic nutrition, 22; her plans perfect if her laws are obeyed, 29; never intended a special diet or bottle of medicine, 30; endeavours to prepare lactic acid in the stomach, 269

Negritos, the, 118

Negroes, the African, 120

Nerve cells, the, specific qualities of, 187

—— fibres, 184

Nervous system, the, influence upon the glands of, 183

Neutralisation, 92

“New Glutton or Epicure,” the, xxviii, 47. See also “Glutton or Epicure”

New Guinea, 124

New Haven (Conn.), scientific experiments at, xiii, 54, 71. See Yale investigation, the, and Yale test, the

Nitrogen, 85, 86

Nitrogenous equilibrium, 86

—— measurements, tests of, 26

“No Breakfast Plan,” the, 396

Nothnagel, experiments of, 343, 345

Northwest London Hospital, the, 8, 92

Nutarians, 90

Nutrient enemata, 367, 379, 380, 382, 388

—— fluid, 381

Nutriment, selection of, 7

Nutrition, economic, experiments upon problem of, ix, x, 48-52; active interest now taken in, x; the financial saving the least of the profits in, xi; the key to England’s welfare, xxv; attitude of the scientific mind towards, xxvii; little accurate knowledge concerning, xxx; psychology of, 6-7; appetite the most important factor in, 6; mechanical and chemical physiology of, 8; its entire principle simple and practical, 19; does not advise avoiding starchy foods for stout people, 21; assures that the same food will add or decrease weight, 21; keeps one in perfect condition, 22; its requirements not hardships but pleasures, 22; not a joke or fad, 24; an appeal to self-examination and self-instruction, 24, 25; first scientific recognition of principles of, 26; medical science not possessed of final information concerning questions of, 52; plan for institution of an international inquiry into the subject of, 53-55; proposed to found an international laboratory of research for the study of, 55-68; no question of greater importance, 72; poverty and vice traced to perversion of, 73; great need of thorough physiological study of, 74; effect of the mental state upon, 74

Nutrition, animal, 56, 57, 58

Nutritive equilibrium, 37; experiments in, 37-39

Nuts, 141, 173; usefulness of, 397

Nuttall, Dr. George H. F., 26, 39, 47

Œsophagus, the, may protect the stomach, 139, 192, 285, 286, 289, 291, 292, 297, 299, 300, 303, 304, 307, 316, 325, 326, 336, 341

Openchowski, experiments of, 305, 325

Orang, the, 115

Oranges, 169

O’Reilly, Surgeon-General, xvii, 69, 70

Ozawa, Professor, 55

Pabulum, the, derivation of, 40, 41

Pacific Islands, the, 124

Padua, Italy, 28

Palate, the, “the dietetic conscience,” 75

Pancreas, the, excited by the vagus and the sympathetic nerves, 183, 270; special relations of acids to, 270, 271, 273, 274, 279

Pancreatic digestion, 395

—— gland, the, 269, 270, 271, 280

—— juice, the, experiments for, 267, 270, 273, 279, 360, 395

Paris, 56, 65

Pastry, 132, 172

Patagonians, the, 128

Pathology, 249

Pavia, University of, 26

Pawlow, Dr. Prof. J. P., 6, 7, 12; researches of, 61, 67, 68; his demonstrations of psychic influence in digestion, 180-283

Peas, 132

Pendelbewegung, the, 342

Pendulum movement, the, 358-360

Penegal, xxxiii

Peptic digestion, 318, 335

Peristalsis, 327, 330, 333, 337, 340, 343, 344, 346, 348, 355-357, 361, 365, 377, 378, 383, 384, 386, 388

Peristaltic wave, the, 343, 353, 365

Pflüger’s Archives, 182

Pharynx, the, 285, 286, 290, 298

Philippines, the, 69

Physicians, most of them called on to restore appetite, 254; their indifference to appetite, 257; in Russia, 260; should bear in mind the question of psychic secretion, 261

Physiology, applied, 251

Pine-apple, 141

Pitcherie, chewing, 129

Polynesia, 128

Poorer classes, the, appetite stronger among, 253; food of, 266, 267

“Popular Science Monthly, The,” xxxiii, 53; Professor Chittenden’s article in, 69-91

Pork, 100, 141

Porridge, 97, 143, 172, 270

Potato, made digestible by saliva, 20; if masticated, need not produce fat, 21; experiments with, 38, 102; yields abundant sugar by long-continued mastication, 142, 146

Potatoes, boiled, 143, 172

Poverty, traced to perversion of nutrition, 73

Proteid, demanded by the appetite, xxxii; the putrid decomposition of, 47; minimum amount of, 74, 78, 79; Asiatics consume smaller proportion of, 82, 83, 85, 98, 100, 272, 394

——, the high, xxxii, xxxiii

——, the low, xxxi, xxxii, xxxiii

—— digestion, perfect, 394, 395

—— molecule, the, isolation of the tryptophane element of, 47

Physiology, experimental, 249; can make no pretence to guide the field of medicine, 251; merely confirms the precepts of instinct, 251

Psychic environment, 12

—— excitation, 259

—— influence, in digestion, 180-283

—— juice, the, 213, 257, 267

—— secretion, 261

—— stimulation, 249

Pultaceous foods, 95, 97

Pyloric sphincter, the, movements of, 314

Pylorus, the, stands guard over the intestines, 139, 141; observations of Fallopius upon, 302; ideas of early writers concerning, 303; later experiments, 304, 307, 308, 315, 316, 317, 325, 326, 328, 330, 331, 332, 333, 340, 341, 360

Rabbit, the, experiments upon, 344, 359, 371

Rage, effect of, 388

Raiser, experiments of, 359, 371

Rectal injections, stimulating effect on movements of small intestine of, 367

Rectum, the, 374, 379, 382

Reed, Dr. Major Walter (martyr to science), 70

Regina Margherita Laboratory, the, summit Monte Rosa, 64, 68

Regurgitation, 35

Rhinitis, 144, 148, 149

Rhythmic segmentation, of the intestinal contents, 347-355, 358, 360, 362, 383, 386

Rice, 82, 132

Rickets, 144

Rigg’s disease, 159, 163

Rjasanzew, Professor, experiments of, 275

Roberts, Sir William, 75, 147

Rockefeller, John D., xxxv

—— Institute of Preventive Medicine, the, 68

Rollbewegung, 345

Röntgen rays, the, Dr. Cannon’s studies with, 180, 284, 287-300, 301-341, 342-388

Roosevelt, President Theodore, 70

Root, Secretary of War, Elihu, 70

Rosa, Monte, 64, 68

Rossbach, experiments of, 305, 309, 311, 313, 314

Roux, experiments of, 314, 315, 327, 328

Royal Society, the, 68

Rumination, 35, 98

Russell, Dr. William, 145

Russia, physicians in, 260; food in, 267, 272

Russian Imperial Military School of Medicine, the, 68

—— peasant, the, 270

Sabbatani, experiments of, 378

St. Martin, Alexis, investigations on, 305, 309

Saliva, its chemical effect upon potato, 20; upon syrup, 21, 33, 34, 35; its action in infant life, 36; an important therapeutic agent, 45, 93, 94, 95; mastication promotes flow of, 96, 101; dry food produces greater flow than moist, 97, 147; complicated physiological functions of, 191-192, 337, 392, 393, 395, 396

Salivary digestion, in the stomach, 335, 341; effect of mastication and cooking of food upon, 391; imperfect, 394

—— glands, the, 155; analogy between the innervation mechanism and the glands of digestion, 188-190; the exciting agencies of the nervous mechanism of, 191; their particular properties, 191-194; differences between the exciting agencies of the different, 194-198; Professor Pawlow’s sham-feeding experiment, 198-211, 280

—— secretion, excitants of, 191

Sapidity, 44

Sauces, 269

Schäfer, 40, 82

Schmidt, experiments of, 202, 204, 231; conditions for success, 204-206

Schütz, experiments of, 305, 308, 309, 310, 311, 313, 314, 327, 332

Schwartz, experiments of, 303, 304

Scientific Assessors, Board of, 67, 68, 181

Secretions, digestive, 180

Secretory fibres, 183

—— nerves, 266

Segmentation, 386, 388

Selection, of nutriment, 7

Self-nutrition, secret of, xii

Sensory nerves, 187

Sham feeding, experiments in, 198-211, 214-246; psychic effect may become an absolute and independent factor in, 209, 279

Sheffield Scientific School, the, experiments at, 53, 68

Sight, the sense of, 210

Sivén, experiments of, 81

Skatol, the odourous, 47

Sleep, exercises no restraining influence upon the gastric glands, 206; effect of, 383-386

Smell, the sense of, 210

Snyder, Dr., experiment in nutritive equilibrium, 37-38

Société de Biologie, the, 46

Sodium, salts of, 277; promote a flow of gastric juice, 277, 278, 279, 281, 282

Soft foods, 97, 129, 136, 142, 160, 162

Solid foods, 94, 268

Solray Sociological Institute, the, 68

Sorbonne, Universitie de la, 68

Soups, 266, 267

South Africa, 11

—— America, 124

“Spectator,” the, 28

Sphincter, the, 315, 316, 317, 331, 333, 341

Spinach, 99

Spirits, 93, 94

Ssanozki, Professor, experiments of, 203, 228

Starch, needed by body, 20, 21, 78, 98; changed into maltose, 101, 102; danger to the stomach in receiving an excess of, 141-146; the last constituent to leave the stomach, 145, 170, 171, 172, 270, 337, 393, 395, 396;

Starling, experiments of, 343, 344, 345, 346, 359

Stews, 266

Stomach, the, struggles bravely to overcome abuse, 19; man’s ignorance concerning requirements of, 23; mastication acts reflexly upon, 102; a long-suffering organ, 138; its danger of receiving an excess of starch, 141; starch the last constituent to leave, 145; necessity of alkali in, 146; secretory work of, 182, 183, 229; secretory nerves of, 210, 227; the seat of certain definite sensations, 241; the initial impulse towards awakening an appetite may originate in, 244, 246; no material progress in the physiology of, 250; Nature endeavours to prepare lactic acid in, 269; acids supplement weak action in, 270, 279; catarrhal affections of, 280; gives no obvious external sign of its workings, 301; studied by means of the Röntgen rays, 301-341; Galen’s observations on the functions of, 302; Fallopius’s views upon, 302; the motor functions of, 304; the anatomy of, 306; its relations to the shadow, 306; the musculature of, 308; normal movements of, 309; the peptonising function of, 314; its appearance at various stages of digestion, 319; composed of two physiologically distinct portions, 324, 340; its movements in vomiting, 325; effect of its movements upon the food, 328; attempts to perform function of teeth, 333; salivary digestion in, 335; inhibition of its movements during emotion, 337

—— fluids, 393, 394

Suffocation, caused by inefficient mastication, 137

Sugar, 21, 78, 89, 95, 169, 337, 393, 395

Sugar-cane, 123, 124, 169

“Sure and Certain Method of Attaining a Long and Healthful Life,” Luigi Cornaro’s treatise upon, 28

Swallowing, facilitated by mastication, 97; mechanism of, 284. See also Swallowing Impulse, the

—— Impulse, the, xxxii, 8, 9, 93, 94

—— reflex, Dr. Van Someren’s, 26, 44

Sweet potato, 124

Sweets, why pleasant, 268, 269

Sympathetic nerve, the, an undoubted exciter of the gastric glands and of the pancreas, 183

Syrup, chemical effect of saliva upon, 21

Tapioca, 132

Taplin, 125

Tasmanians, the, 122

Taste, delicacy of the sense of, 22, 23; should be dissipated in the mouth, 93, 210; necessary to give an impulse to the organs of, 253; the nutritive value of food should be considered rather than, 261

—— gratification, 93

Tea, 132

Tea-taster, the professional, methods of, 23, 93

Teeth, the, influence of mastication upon, 110; changes during man’s evolution, 115-121; instances of vigorous use, 122-126; irregularity in, 156; evils of imperfect use of, 157; examination of, 174-179; the

stomach attempts to perform function of, 333

“Text-Book of Physiology,” Schäfer’s, 40

“That Last Waif: or Social Quarantine,” xxv

Therapeutic experiments, pathological, 249

Therapeutics, precepts of, 272

Thierfelder, 39

Thirst, 95

Thompson, Dr., 142

—— Prof. W. H., 180, 181

Thorax, the, 290

Tobacco-chewing, 103, 129

Tokio, University of, 55

Tongue, the, needs exercise, 154

Tonic constrictions, the, 344; the appearance of, 370-373, 385, 387

—— rings, the, 373

Tonsillitis, 144, 148

Tooth-brush, the, 177

Tooth-powder, 178

Toxins, absorbed into the blood, 40, 41, 44, 143

Training, for athletes, why necessary, 22

“Traité Analytique de la Digestion,” Blondlot’s, 181

Treves, Sir Frederick, on bolting of food, 140, 141

Trinity College, Dublin, 180

Trophic fibres, 183

Tryptophane, 47

Tuberculosis, 144

Turin, Italy, Congress of Physiologists at, 26, 48, 56, 91

——, University of, 68, 284

Urine, should be inoffensive, 42, 93, 274

Vagus nerve, the, an undoubted exciter of the gastric glands and of the pancreas, 183; its functions almost interminable, 183, 249

Van Someren, Dr. Ernest, xxv, 7, 12; his paper “Was Luigi Cornaro Right?” 26-46; his swallowing reflex, 26, 44; his experiments confirmed by Marckwald, 46; Sir Michael Foster’s Note upon his paper, 48-52; the Cambridge tests, 49-52, 53, 60, 91, 92, 98

Van Valzah, 146

Veal, 100

Veddahs, the, 128

Vegetable food, experiments with, 40; necessitates more thorough mastication than animal, 97, 98, 173; influenced more by cooking than animal, 118, 132, 170

Vegetables, 43, 78

Venice, Italy, 30, 63, 64, 91

Vermicelli, 132

Vermicular contraction, 343

—— wave, the, 345

Vermiform appendix, the, 140

Vice, traced to perversion of nutrition, 73

Vienna, 65

—— bread, 131

Vinegar, 269

Vivisection, 303, 305

Voice, the, requires lusty exercise in youth, 149

Voit diet, the, 76, 81, 84, 86

Vomiting, the act of, 193, 303; movements of the stomach in, 325, 341

Wallace, Dr. G. Sim, 110, 113, 130, 154, 158, 161, 169, 174, 177

Walther, Dr., experiments of, 267, 276

Washington, D. C., 70

Water, how to drink, 9, 34, 95, 268, 391, 392

—— biscuit, 391

Weight, must become normal, 43

Welch, Dr. Prof. William H., 67, 68

Wepfer, experiments of, 303, 304

Wheat, unground pearl, 392, 393, 394

—— flour, 392

Wine, how to take, 9, 22, 23

Wine-tasters, the professional, methods of, 23, 93

Wolves, experiments upon, 303

Wood, Maj. Gen. Leonard, 69, 70

Worry, causes indigestion, 7

Wulfson, Dr., 197

X-ray. See Röntgen ray

Yale investigation, the, x, xi, xiii-xv, xvii, xviii, xix, xxxiii

—— Gymnasium, the, 87

—— test, the, 5, 69, 75-91

—— University, 68

Z, in the nutrition alphabet, 10, 12;

Zuntz, Dr. Prof. N., 67, 68

FOOTNOTES:

Appetite alone can judge accurately of the former, and the true Swallowing Impulse is the limitation of the latter. If we study the natural instincts, the rest will take care of itself.

This is very strong evidence that appetite knows what to do and when to do it, if you study and consult it and give it a chance to prescribe.

The Yale test reported herein by Professor Chittenden showed the possibility of full alimentation according to the requirements of Economic Nutrition in from 24 to 26 minutes daily, which is less than 1∕48 of a day. Beginners of the practice of careful mouth-treatment of their food may require more time, but, whatever it may be, it is worth it. A little care for a short period will establish a right habit, and then no further tedious attention nor unusual time will be necessary to accomplish a perfectly healthy nutrition.

Physiological Economy in Nutrition: The Frederick A. Stokes Company, New York.

William Heinemann: London.

The author is not yet permitted to publish the particulars of these reforms in process, but he has official information regarding them and is in full sympathy with them.

Dental surgeons now speak of the upper jaw as the maxilla, and of the lower jaw as the mandible.

This subject I am obliged to deal with very briefly, and am compelled to omit the reasons for my conclusions.

Recent observations go to show that man possesses no power of digesting cellulose, though this substance is to a limited extent capable of solution by the agency of bacteria in the lower portions of his alimentary canal.

I am under great obligation to Miss Eva Dunn, who has collected valuable information for me on this and kindred subjects.

Social History of the Races of Mankind, 1881.

S. Powers: Tribes of California, 1877.

E. M. Curr: The Australian Races, 1886-7. Taplin: The Narrinyeri; an account of Tribes of South Australian Aborigines, 1879.

J. F. Nansen: Eskimo Life, 1893.

Dr. Kane: Arctic Exploration, 1854.

E. Astrup: With Peary near the Pole, 1898.

Sir George Grey: Journal of Two Expeditions in North-West and Western Australia, 1841.

Muster: With the Patagonians, 1869.

Bailey: Transactions of the Ethnological Society, 1862.

E. M. Curr: The Australian Race, 1886-87.

The Causes and Prevention of Decay in Teeth, pp. 88, 89. London, 1902.

Gilbert Barling also traces the relationship between appendicitis and diet. “In a considerable number of cases,” he writes, “the attack of appendicitis can be directly attributed to unsuitable food--pork, mackerel, over-ripe or under-ripe fruit, uncooked vegetables” (Brit. Med. Jour., vol. i., 1903, p. 61).

My friend, Dr. Thompson, undertook, at my suggestion, some experiments to test the digestibility of raw starch within the mouth; he found that raw potato yields abundant sugar when subjected to long-continued mastication.

The Lancet, March 21st, 1903, p. 806.

Brit. Med. Jour., Epitome, vol. i., 1903, p. 45.

A further aid to the circulation in the naso-pharynx is afforded by the lusty use of the voice. It a natural for the young human to cry and to shout, and unless this instinct is allowed full play the child is apt to suffer in health. I cannot but think that the modern child is too much repressed in this respect, and that he is not afforded, especially in towns, proper opportunity of venting his vocal energy in out-door play. May we not have here a contributory factor in the causation of adenoids?

Among the Australian skulls I have examined in museums caries of the wisdom teeth--i.e., in those very teeth which, as shown by their atrophy, are least used--is by no means uncommon (though it is possible that some of the skulls belong to natives who have embraced the dietetic customs of the white man). I submit that this fact may fairly be used as an argument in favour of the view that inefficient use of the teeth predisposes them to caries by interfering with their resisting power, though it must be acknowledged that the position of the wisdom teeth places them at a disadvantage, owing to the tendency of food to accumulate about them, especially in undeveloped jaws in which they have not adequate room.

This film can be felt by the tongue as a somewhat rough covering, which gives place to a smooth surface after the use of the tooth-brush.

By the term “external stimulus” I mean here without distinction every outward agency of nature, as well as every agency which has its seat within the organism. The word “external” applies here to everything with the single exception of the nervous system itself.

One may be permitted to use this expression for the sake of brevity.

Kwas is a favourite Russian drink, prepared from water, bread or meal, with malt and yeast. It contains a considerable quantity of lactic acid, some acetic acid, and other products of fermentation.

An investigation by Cannon and Day (American Journal of Physiology, 1903) has confirmed this conclusion. An hour after starchy food mixed with saliva was ingested a unit volume of the food in the cardiac end of the stomach contained almost twice the amount of sugar found in a unit volume of the food in the pyloric end.

The results of this investigation were reported to the Boston Society of Medical Sciences, November 19, 1901.

Without the possibility of seeing the relations of a movement to the ends of the intestine, it cannot be stated absolutely whether the movement is peristaltic or antiperistaltic. Such relations can be seen on the fluorescent screen only near the stomach and near the ileocæcal valve. The evidence that advancing peristalsis is the normal movement is so overwhelming that I have assumed that when food is moving in loops not visibly related to fixed points it is moving forward.

In this case the fæces were soft.

While Napoleon was building his power and fame he was very careful and abstemious, but in later life succumbed to luxury and gluttony; Bismarck’s rise and decline were similarly related to dietary influences.--H. F.