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BOSTON MEDICAL LIBRARY
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Francis A.Countway Library of Medicine
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EXPERIMENTS AND OBSERVATIONS
ON THE
GASTRIC JUICE,
AND THE
PHYSIOLOGY OF DIGESTION.
Digitized by the Internet Archive
in 2011 with funding from
Open Knowledge Commons and Harvard Medical School
http://www.archive.org/details/experimentsobserOObeau
EXPERIMENTS AND OBSERVATIONS
ON THE
GASTRIC JUICE,
AND THE
PHYSIOLOGY OF DIGESTION.
BY
WILLIAM BEAUMONT, M.D.
SURGEON IN THE UNITED STATES' ARMY. REPRINTED FROM THE PLATTSBURGH EDITION, WITH NOTES BY
ANDREW COMBE, M.D.
FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS OF EDINBURGH ; PHYSICIAN
EXTRAORDINARY TO THE QUEEN IX SCOTLAND, AND CONSULTING
PHYSICIAN TO THE KING AND QUEEN OF THE BELGIANS.
EDINBURGH:
MACLACHLAN & STEWART, SOUTH BRIDGE ; AND SIMPKIN, MARSHALL & CO., LONDON.
MDCCCXXXVIII.
/3 a. 4 f / — i^^
PRINTED BY NEILL AND CO., OLD FISHMARKET, EDTNBQRGH.
PREFACE BY THE EDITOR.
The reasons which have induced me to reprint the present work from the American original, are, 1st, A strong sense of its inherent importance and of the numerous applications which may be made of the facts and principles developed in it to the pre- vention and cure of disease ; ^dly, Its comparative inaccessibility to the European physiologist from the difficulty which still exists of procuring it on this side of the Atlantic ; and, lastly. An earnest desire that the author should obtain that credit which is unquestionably due to his disinterested and indefa- tigable labours.
The value of Dr Beaumonfs experiments consists partly in the admirable opportunities for observa- tion which he enjoyed, and partly in the candid and truth-seeking spirit in which all his inquiries seem to have been conducted. Two or three other cases have indeed occurred in which the cavity of the sto- jnach was laid open by external wounds, but in
VI PREFACE BY THE EDITOR.
none except that of Alexis St Martin, observed by Dr Beaumont, did perfect recovery take place while the opening remained unclosed. In all of them, death occurred in a longer or shorter time, without affording any opportunity of observing the pheno- mena of really healthy digestion. In St Martin, however, notwithstanding the severity of the wound, recovery was so complete that he continued for years (and, I believe, still continues) to lead a laborious life in the enjoyment of vigorous health, while diges- tion was as regular and effective as if no opening into the stomach had ever existed, or as if that once made had been entirely closed. For nearly eleven years after his accident, St Martin continued more or less under Dr Beaumont's observation, and during several years of that time lived in his house as a do- mestic servant, for the express purpose of being ex- perimented upon. So far, then, as opportunity for observation was concerned, nothing could surpass that enjoyed by Dr Beaumont.
That Dr Beaumont eagerly and zealously availed himself of his unusual advantages, the following pages furnish ample evidence, and it would, I think, be difficult to point out any observer who excels him in devotion to truth, and freedom from the trammels of theory or prejudice. Among the disci- plined physiologists of Europe, a more systematic experimenter might certainly have been found, but
PREFACE BY THE EDITOR. Vll
in Dr Beaumont's instance, the absence of systema- tized inquiry — made too generally in support of a preconceived theory, and therefore apt to mislead as well as to instruct — is more than compensated by the implicit reliance which one feels can be placed on the accuracy and candour of his statements. Having no theory to support, and no favourite point to establish, Dr Beaumont tells plainly what he saw, and leaves every one to draw his own inferences, or where he lays down conclusions, he does so with a degree of modesty and fairness of which few perhaps in his circumstances would have been capable,*
But, it may be said, singularly favourable as t)r Beaumont's opportunities were, he has made no ori- ginal discovery in the physiology of digestion. To a certain extent this is true, for in the proper sense of the word he has not made and does not claim to have made any discovery, but he has done what is at least equally essential for practical purposes. By separating the truth clearly and unequivocally from the numerous errors of fact and opinion with which it was mixed up, and thus converting into certain-
* In proof of Dr Beaumont's disinterestedness in conducting the inquiry, I may mention that I have learned from private sources that the expenses attending the various series of experi- ments exceeded in amount L.700 Sterling, the whole of which was defrayed by himself, and for repayment of which he was ad- vised to apply to Congress, on the ground of the public being in- terested in the promotion of scientific discovery ; but although the American Treasury was at the time literally overflowing, the ap- plication was refused.
Vlll PREFACE BY THE EDITOR.
ties points of doctrine in regard to which positive proofs were previously inaccessible, he has given to what was doubtful or imperfectly known, a fixed and positive value, which it never had before, and which being once obtained, goes far to furnish us with a clear, connected, and consistent view of the general process and laws of digestion. Other physio- logists have attempted to effect the same end by expe- riments performed upon the lower animals, but these are open to so many forcible objections, that we can- not always adopt their conclusions, even where they seem to be most clearly deduced. Not to mention the cruelty inseparable from the performance of such experiments, the pain which the animal suflPers ne- cessarily disturbs the regularity of the function under examination, and in a greater or less degree vitiates the results. And even if this were not the case, the difference between the digestive organs in man and in the lower animals is so great, that it would often be unsafe to assume conclusions as applicable to the former which have been verified only in the latter.
In perusing the present volume, it is proper to bear in mind the circumstances under which the ex- periments were made, and the account of them was written. Dr Beaumont was far from enjoying the leisure, resources, and scientific co-operation so easily accessible to the physiologists of any of our Euro-.
PREFACE BY THE EDITOR. IX
pean capitals. Stationed in a comparatively remote quarter in the exercise of his duties as an army sur- geon, and previously unaccustomed to minute phy- siological research, he conducted his inquiry under many minor disadvantages. When he came to pub- lish also, his want of experience in writing prevent- ed him from making the most of his materials, and doing that justice to himself which he might other- wise have easily accomplished. In the arrangement of his experiments, for example, Dr Beaumont has followed the order of time, and thus mingled many things together, where a more practised inquirer would have classified them according to the subjects in illustration of which they were performed, and thus given a greater unity of purpose to each of the different series of which they are composed. But al- though this defect diminishes the facility of access to the results, it by no means detracts from their in- trinsic value. On the contrary, the very absence of systematized arrangement leaves a character of even greater trust-worthiness attached to the individual observations than if the latter had been made under the influence of some prominent guiding principle, which might have given a bias to the mind.
When preparing the following pages for the press, I took a good deal of trouble in an attempt to remedy the above defects of arrangement, but the original absence of method had led to such an inter-
X PREFACE BY THE EDITOR.
mixture of topics as to render their proper classifi- cation impossible, and I was obliged to give it up. I have, however, endeavoured to facilitate reference by prefixing to each chapter a short summary of its contents, and by adding illustrative notes wherever it could be done with advantage. To the substance of the text I have, of course, carefully adhered ; but I have taken the liberty of altering, and I trust improving, the arrangement of the table illustrative of the digestibility of different kinds of food, occur- ring at page 292, and of the " concluding Infe- rences^' at page 298. The object of both these al- terations was simply to present the different sub- jects in a more natural and instructive order than the author himself has done.
As the first division of the work now stands, the reader will remark a considerable similarity between it and the corresponding part of a volume published by me about two years ago.* The similarity exists, so far as the physiological expositions are concerned, because the subjects treated of are nearly the same, and most of the doctrines advanced are peculiar to neither of us, but are those which have long been more or less firmly established ; and also because I naturally availed myself of Dr Beaumont's observa- tions, as the latest and most accurate, wherever I
* The Physiology of Digestion considered in relation to the Principles of Dietetics, 2d edition. Edinburgh, 1837.
PREFACE BY THE EDITOR. XI
could turn them to account in confirming what was before doubtful, or correcting what he proved to be erroneous. But, except in the purely physiological ex- position of the subjects, there is a difference between us, corresponding to the different purposes for which we wrote. Dr Beaumont's sole object was to extend our knowledge of the physiology of digestion, without direct reference to any practical end. My chief aim, on the other hand, was to lay the foundation of a proper system of Dietetics, and to treat of the or- gans and physiology of digestion, only as bearing upon this point, and as the real basis on which all dietetic rules ought to rest. Accordingly, although we both treat of Mastication, Insalivation, Degluti- tion, Chymification, &c., Dr Beaumont limits him- self purely to a physiological exposition, while I treat of them, not only physiologically, but also with re- ference to the organization which executes them, and the means by which their healthy action may be most effectually promoted, preserved, or restored. But, while profiting by that gentleman's labours to enforce more authoritatively the practical truths which it was my chief object to inculcate, I have always been anxious to render him that ample measure of justice to which he is so eminently entitled ; and accordingly, in the preface to my book, I expressly mention, that, " in preparing the present volume for the press, I have derived the
Xll PREFACE BY THE EDITOR.
utmost advantage from a very valuable work by Dr Beaumont, an American writer, which, though scarcely at all known in this country, contains an authentic record of some of the most curious and instructive observations which have ever been made on the subject of Digestion. That excellent and enlightened physiologist had the rare good fortune to meet with a case in which an artificial opening into the stomach existed, through which he could see every thing that took place during the progress of healthy digestion ; and, with the most disinterest- ed zeal and admirable perseverance, he proceeded to avail himself of the opportunity thus afforded of advancing human knowledge, by engaging the pa- tient, at a heavy expense, to live with him for seve- ral years, and become the subject of numerous and carefully conducted experiments. Of the results thus obtained, I have not scrupled to make the freest and most ample use, — not from considering them as positively new (for even Dr Beaumont lays little claim to the merit of a discoverer), but because they come before us so entirely freed from the nu- merous sources of error and doubt which formerly impaired their value, that they can now, for the first time, be safely trusted as practical guides in the science of Dietetics. From Dr Beaumont's work also being still inaccessible to the British reader, it is a bare act of justice towards him, and also the
PREFACE BY THE EDITOR. XIU
best way of fulfilling the objects he had in view, to make its contents known as widely as possible ; for wherever they are known, they will be acknowledged to redound to his credit, not less as a man than as a philosopher."— (Preface, p. xxv.)
So much, indeed, did I consider the republication of Dr Beaumon^s work as a matter of justice to him, that, had I not expected its appearance from some other quarter long ago, I would have undertaken the task at an earlier period, and, even now, I can account for the omission only by supposing that very few copies of the original have reached this country. Everywhere, both in British and foreign books, we meet with reference to, and often inac- curate extracts from it, but almost nowhere is it spoken of as if the work itself had been consulted. I trust then, that in now presenting it, I shall be con- sidered as rendering an acceptable service to British and Continental physiologists, as well as a pleasing act of justice to its deserving author.
Actuated by the feeling that knowledge is valua- ble chiefly for the uses to which it may be applied, I have ventured to add a supplementary chapter, embodying a few of the practical conclusions which may be deduced from the experiments of Dr Beau- mont, but finding that, to do full justice to them, would both add to the size of the volume, and ne- cessarily involve a repetition of several topics already
XIV PREFACE BY THE EDITOU.
discussed in the work referred to, I have judged it better not to enter too largely upon this branch of the subject, particularly as the professional reader can deduce his own inferences for himself. I may, however, add, in reference to the table exhibit- ing the relative digestibility of different articles of diet, that its results ought to be received, not as certainties, but only as approximations to the truth. The rapidity of digestion is so much influenced by the quantity eaten, the degree of preparatory mas- tication, the amount of exercise, the mode of life, and state of health, that no positive conclusions on that point can be drawn, except where due attention has been paid to all these modifying circumstances. In the following experiments, however, Dr Beau- monfs chief aim was to ascertain the nature and laws of the digestive process, and his observations on the comparative digestibility of different sub- stances, were thus too incidental to be relied upon as minutely accurate ; but in a general way they are well worthy of attention.
In the second edition of the " Physiology of Di- gestion" I ventured to suggest, that some of our scientific associations, such as the Royal Society or British Association, would do science a service and themselves an honour, by using their influence and means to have St Martin brought over to this coun- try, and the remainder of the subject fully investi-
PREFACE BY THE EDITOR. XV
gated under the direction of a committee of their number. An opportunity of this kind may never occur again, and it will be a source of lasting re- gret, and even of merited reproach, if it be allowed to pass away without being turned to the best pos- sible account. If the suggestion now thrown out shall ever be acted upon, special care should be taken not to injure St Martin's health by withdrawing him entirelv from his accustomed diet and mode of Kfe, otherwise the whole value of the experiment may be lost, — the object being to ascertain the laws and con- ditions of HEALTHY DIGESTION.
Edinburgh, April 1838.
CONTENTS.
Author's Prefac e, . . . . . 1-3
CHAPTER I.
HISTORY OF THE CASE OF ALEXIS ST MARTIN.
St Martin's Stomach perforated by a musket-shot — Situation and nature of the wound — His treatment and recovery — External opening into the stomach remains unclosed — Mode of extracting gastric juice through the opening — Extraordinary facilities presented for experimenting on digestion, by introducing and withdrawing food through the opening, and observing its changes — Woodcuts repre- senting the appearance of the wound after recovery, and the valve by which the opening is filled up, . • 7-23
CHAPTER II. OF ALIMENT.
Man an omnivorous animal — Nature of animal food — The ulti- mate principles of aliment the same, whether derived from animals or vegetables — The action of the stomach on food always the same — The quantity of nutriment re- quired varies according to circumstances — The quality is also important — Variety is required — Table of digesti- bility of various substances — Animal more quickly di- gested than vegetable food — Minuteness of division in- fluential on digestion — Fish easily digested — Condiments not essential — Drink necessary — Effect of Wine — Quan- tity more influential than quality, .... 24.42
XVlll CONTENTS.
CHAPTER III. OF HUNGER AND THIRST.
Hunger — Its exciting cause — Different theories of— The Au- thor's theory of hunger — Thirst and its causes — Objec- tions to the Author's theory of hunger, . . . 43-51
Note by the Editor, 51-53
CHAPTER IV.
OF SATISFACTION AND SATIETY.
Quantity of food required — Satiety not a proper guide — The first feeling of satisfaction is the true indication — Gastric juice secreted in relation to this indication, . . 54-57
CHAPTER V. MASTICATION, INSALIVATION, AND DEGLUTITION.
Uses of mastication — Nature and use of saliva — Saliva not essential to digestion — Mastication essential as a meaaas of dividing food into minute portions — Deglutition ought to be slow, as the stomach admits only of slow disten- tion, 58-63
Note by the Editor, 63
CHAPTER VI.
OF DIGESTION BY THE GASTRIC JUICE.
Chymification — Agents of. — Spallanzani's theory of Diges- tion— Common opinions regarding the gastric juice — Gas- tric juice has a solvent power — Analysis of — Composition of — Its action is purely chemical — Gastric juice described — Its quantity proportioned to wants of the system — Its secretion and action begin on the contact of food— Evils of frequent eating explained — Gastric juice supplied to all the food at once when the latter is not in excess — Old and new food mix — Effects of exercise on digestion — Bile not essential to chymification — Chyme, its nature and pro- gress— Montegre's theory of digestion — Smith's and Jack- son's theories — General remarks, .... 64-93
CONTENTS, XIX
CHAPTER VII.
OF THE APPEARANCE OF THE VILLOUS COAT, AND OF THE MOTIONS OF THE STOMACH.
Appearance of the villous coat — Gastric Papillae — Healthy aspect of the villous coat — Its aspect in disease — Motions in the stomach — Effects of — Order of contraction in the muscular fibres of the stomach — Passage of the chyme out of the stomach, 94-10?
CHAPTER VIII.
OF CHYLIFICATION, AND THE USES OF THE BILE AND • PANCREATIC JUICE,
Passage of chyme into the duodenum — and there converted into chyle by the agency of the bile and pancreatic juice — Chyle always the same in health — Changes occurring in the duodenum, ....... 108-116
EXPERIMENTS AND OBSERVATIONS.
First Series, 117-14!
Second Series, 124-166
Third Series, 167-242
Note by the Editor, 243-243
Microscopic Examinations, 245-246
Fourth Series, 247-255
Note by the Editor, . 253-255
Experiments, &c. 255-291
Table shewing the Mean Time of Digestion of tlie different Articles of Diet, naturally, in the Stomach, and artificially in Vials, on a Bath, ...... 292-29S
Table shewing the Temperature of the Interior of the Stomach in different Conditions, taken in different Seasons of the Year, and at various times of the Day, from 5 o'clock in the Morning till 12 o'clock at night, . . . 295-296
Inferences from the foregoing Experiments and Observa- tions, 298-303
Concluding Remarks by the Editor, . . . . 303-328
PREFACE.
The present age is prolific of works on physiology ; therefore in offering to the public another book relative to an important branch of this science, it will, perhaps, be necessary to assign my motives.
They are, first, a wish to comply with the repeated and urgent solicitations of many medical men who have become partially acquainted with the facts and observa- tions it is my intention to detail ; men in whose judg- ment I place confidence, and who have expressed their conviction of the deep importance of the experiments, the result of which I mean herewith to submit to the public : secondly, (and it is that which mainly influences me,) my own firm conviction that medical science will be forwarded by the publication.
I am fully aware of the importance of the subject which these experiments are intended to illustrate, as well in a pathological as in a physiological point of view ; and I am therefore willing to risk the censure or neglect of critics, if I may be permitted to cast my mite into the treasury of knowledge, and to be the means, either directly or in-
^ PREFACE.
directly, of subserving the cause of truth, and amelio- rating the condition of suffering humanity.
I make no claim to originality in my opinions, as it re- spects the existence and operation of the gastric juice. My experiments confirm the doctrines (with some modi- fications) taught by Spallanzani, and many of the most enlightened physiological writers. They are experiments made in the true spirit of inquiry, suggested by the very extraordinary case which gave me an opportunity of making them. I had no particular hypothesis to support ; and I have therefore honestly recorded the result of each experiment exactly as it occurred.
The reader will perceive some slight seeming discre- pancies, which he may find it difficult to reconcile ; but he will recollect that the human machine is endowed with a vitality which modifies its movements in different states of the system, and probably produces some diversity of effects from the same causes.
I had opportunities for the examination of the interior of the stomach, and its secretions, which have never be- fore been so fully offered to any one. This most im- portant organ, its secretions and its operations, have been submitted to my observation in a very extraordinary man- ner, in a state of perfect health, and for years in succes- sion. I have availed myself of the opportunity afforded by a concurrence of circumstances which probably can never again occur, with a zeal and perseverance proceed- ing from motives which my conscience approves ; and I now submit the result of my experiments to an enlight-
i
PREFACE. 3
ened public, who, I doubt not, will duly appreciate the truths discovered, and the confirmation of opinions which before rested on conjecture.
I submit a body of facts which cannot be invalidated. My opinions may be doubted, denied, or approved, ac- cording as they conflict or agree with the opinions of each individual who may read them ; but their worth will be best determined by the foundation on which they rest — the incontrovertible facts.
I avail myself of this opportunity to make my grateful acknowledgments to Doctor Joseph"^ Lovell, Surgeon- General of the United States' Army, (to whom I am un- der obligations for personal kindness and official exer- tions in affording facilities for prosecuting the experi- ments ;) — to Professors Silliman, Knight, Ives, and Hub- bard, of Yale College ; Dunglison, of the Virginia Uni- versity, and Sewal, Jones, Henderson, and Hall, of Columbian College, for their unsolicited friendship ; for the interest which they have taken in the experiments, and for the generous encouragement which they have given to the proposed publication. To Doctor Samuel Beaumont, of Plattsburgh, N. Y., I am particularly in- debted, for the assistance which he has rendered me in arranging and preparing my notes for the press.
Plattsburgh, 1833.
PRELIMINARY OBSERVATIONS.
( 7 )
CHAPTER I.
HISTORY OF THE CASE OF ALEXIS ST MARTIN.
St Martin's Stomach perforated by a musket-shot — Situation and nature of the wound — His treatment and recovery — Ex- ternal opening into the stomach remains unclosed — Mode of extracting gastric juice through the opening — Extraordinary facilities presented for experimenting on digestion, by intro- ducing and withdrawing food through the opening, and ob- serving its changes — Woodcuts representing the appearance of the wound after recovery, and the valve by which the opening is filled up.
The experiments which follow were commenced in 1825, and have been continued, with various interrup- tions to the present time, (1833). The opportunity for making them was afforded to me in the following way.
Whilst stationed at Michillimackinac, Michigan Terri- tory, in 1822, in the military service of the United States, the following case of surgery came under my care and treatment.
Alexis St Martin, who is the subject of these experi- ments, was a Canadian, of French descent, at the above mentioned time about eighteen years of age, of good con- stitution, robust and healthy. He had been engaged in the service of the American Fur Company, as a voyageur, and was accidentally wounded by the discharge of a mus- ket, on the 6th of June 1822.
8 CASE OF ALEXIS ST MARTIN.
The charge, consisting of powder and duck-shot, was received in the left siae of the youth, he being at a dis- tance of not more than one yard from the muzzle of the gun. The contents entered posteriorly, and in an oblique direction, forward and inward, literally blowing off inte- guments and muscles of the size of a man's hand, frac- turing and carrying away the anterior half of the sixth rib, fracturing the fifth, lacerating the lower portion of the left lobe of the lungs, the diaphragm, and perforating the stomach.
The whole mass of materials forced from the muskety together with fragments of clothing and pieces of frac- tured ribs, were driven into the muscles and cavity of the chest.
I saw him in twenty-five or thirty minutes after the accident occurred, and, on examination, found a portion of the lung as large as a turkey's egg, protruding through the external wound, lacerated and burnt ; and imme- diately below this, another protrusion, which, on further examination, proved to be a portion of the stomach, la- cerated through all its coats, and pouring out the food he had taken for his breakfast, through an orifice large enough to admit the forefinger.
In attempting to return the protruded portion of the lung, I was prevented by a sharp point of the fractured rib, over which it had caught by its membranes ; but by raising it with my finger, and clipping off the point of the rib, I was able to return it into its proper cavity, though it could not be retained there, on account of the inces«
CASE OF ALEXIS ST MARTIN. 9
sant efforts to cough. The projecting portion of the stomach was nearly as large as that of the lung. It passed through the lacerated diaphragm and external wound, mingling the food with the bloody mucus blown from the lungs.
, After cleansing the wound from the charge and other extraneous matter, and replacing the stomach and lungs as far as practicable, I applied the carbonated fermenting poultice, and kept the surrounding parts constantly wet with a lotion of muriate of ammonia and vinegar ; and gave internally the aq. acet. am. with camphor, in liberal quantities.
Under this treatment a strong reaction took place in about twenty-four hours, accompanied with high arterial excitement, fever, and marked symptoms of inflammation of the lining membranes of the chest and abdomen, great difficulty of breathing, and distressing cough. He was bled to the amount of eighteen or twenty ounces, and took a cathartic. The bleeding reduced the arterial ac tion, and gave relief. The cathartic had no effect, as it escaped from the stomach through the wound.
On the fifth day a partial sloughing of the integu- ments and muscles took-place. Some of the protruded portions of the lung, and lacerated parts of the stomach, also sloughed, and left a perforation into the stomach, plainly to be seen, large enough to admit the whole length of my fore-finger into its cavity ; and also a pas- sage into the chest, half as large as my fist, exposing to
10 CASE OF ALEXIS ST MARTIN.
view a part of the lung, and permitting the free escape of air and bloody mucus at every respiration. A violent fever continued for ten days, running into a typhoid type, and the wound became very fcetid.
On the eleventh day, a more extensive sloughing took place, the febrile symptoms subsided, and the whole sur- face of the wound assumed a healthy and granulating ap- pearance.
For seventeen days, all that entered his stomach by the oesophagus, soon passed out through the wound ; and the only way of sustaining him was by means of nutri- cious injections per anum, until compresses and adhesive straps could be applied so as to retain his food. During this period no alvine evacuations could be obtained, al- though cathartic injections were given, and various other means were adopted to promote them.
In a few days after firm dressings were applied, and the contents of the stomach retained, the bowels became gradually excited, and, with the aid of cathartic injec- tions, a very hard, black, fcetid stool was procured, fol- lowed by several similar ones ; after which the bowels became quite regular, and continued so. The cataplasms were continued until the sloughing was completed, and the granulating process fully established ; and were af- terwards occasionally resorted to, when the wound be- came ill conditioned. The aq. acet. am. with camphor was also continued for several weeks, in proportion to the febrile symptoms and the foetid condition of the wound.
CASE^OF ALEXIS ST MARTIN. 11
No sickness nor unusual irritation of the stomach, not even the slightest nausea, was manifest during the whole time ; and after the fourth week, the appetite became good, digestion regular, the alvine evacuations natural, and all the functions of the system perfect and natural. By the adhesion of the sides of the protruded portions of the stomach to the pleura costalis and the external wound, a free exit was aflPorded to the contents of that organ, and effusion into the abdominal cavity was thereby prevented.
Cicatrization and contraction of the external wound commenced on the fifth week ; the stomach became more firmly attached to the pleura and intercostals, by its ex- ternal coats ; but shewed not the least disposition to close its orifice ; this (the orifice) terminated as if by a natu- ral boundary, and left the perforation, resembling, in all but a sphincter, the natural anus, with a slight prolapsus. ^' Whenever the wound was dressed, the contents of the stomach would flow out, in proportion to the quantity recently taken. If the stomach happened to be empty, or nearly so, a partial inversion would take place, unless prevented by the application of the finger. Frequently in consequence of the derangement of the dressing, the inverted part would be found of the size of a hen's egg. No difficulty, however, was experienced in reducing it by gentle pressure with the finger, or a sponge wet with cold water, neither of which produced the least pain.
The annexed figure represents the protruded portion. AAAAA, are the folds or rugae of the inner surface of
12 CASE OF ALEXIS ST MARTIN.
the stomach ; BBB are the interstices filled with mu- cous substance ; C shews the situation of the nipple.
In the seventh week, exfoliation of the ribs, and a separation of their cartilaginous ends, began to take place.
The sixth rib was denuded of its periosteum for about two inches from the fractured part, so that I was obliged to amputate it about three or four inches from its arti- culation with the rib. This I accomplished by dissect- ing back the muscles, securing the intercostal artery, and sawing off the bone with a very fine narrow saw, made for the purpose, introduced between the ribs, without in- jury to the neighbouring parts. Healthy granulations soon appeared, and formed soundly over the amputated
CASE OF ALEXIS ST MARTIN. 13
end. About half the inferior edge of the fifth rib exfol- iated, and separated from its cartilage.
After the removal of these pieces of bone, I attempted to contract the wound, and close the perforation of the stomach, by gradually drawing the edges together with adhesive straps, laid on in a radiated form.
The circumference of the external wound was at least twelve inches, and the orifice in the stomach nearly in the centre, two inches below the left nipple, on a line drawn from this to the point of the left ilium.
To retain his food and drinks, I kept a compress and tent of lint, fitted to the shape and size of the perforation, and confined there by adhesive straps.
After trying all the means in my power for eight or ten months to close the orifice, by exciting adhesive in- flammation in the lips of the wound, without the least appearance of success, I gave it up as impracticable in any other way than that of incising and bringing them together by sutures ; an operation to which the patient would not submit.
By the sloughing of the injured portion of the lung, a cavity was left as large as a common sized tea cup, from which continued a copious discharge of pus for three months, when it became filled with healthy granulations, firmly adhering to the pleura, and soundly cicatrized over that part of the wound.
Four months after the injury was received, an abscess formed about two inches below the wound, nearly over the cartilaginous ends of the first and second false ribs.
14 CASE OF ALEXIS ST MARTIN.
very painful, and extremely sore, producing violent symp- tomatic fever. On the application of an emollient poul- tice, it pointed externally. It was then laid open to the extent of three inches, and several shot and pieces of wad extracted. After which a gum -elastic bougie could be introduced three or four inches in the longitudinal di- rection of the ribs, towards the spine. Great pain and soreness extended from the opening of the abscess, along the track of the cartilaginous ends of the false ribs, to the spine, with a copious discharge from the sinus.
In five or six days, there came away a cartilage, one inch in length. In six or seven days more, another, an inch and a half long ; and in about the same length of time, a third, two inches long, were discharged. And they continued to come away every five or six days, un- til Jive were discharged from the same opening, the last three inches in length. They were all entire, and evi- dently separated from the false ribs.
The discharge, pain, and irritation, during the four or five weeks these cartilages were working out, greatly reduced the strength of the patient, produced a general febrile habit, and stopped the healing process of the ori- ginal wound.
Directly after the discharge of the last cartilage, in- flammation commenced over the lower end of the ster- num, which, by the usual applications, terminated in a few days in a large abscess, and from which, by laying it open two inches, I extracted another cartilage, three inches in length. The inflammation then abated ; and
CASE OF ALEXIS ST MARTIN. 15
in a day or two another piece came away, and the dis- charge subsided.
To support the patient under all these debilitating cir- cumstances, I administered wine, with diluted muriatic acid, and thirty or forty drops of the tincture of assafoe- tida, three times a-day ; which appeared to produce the desired eflPect, and very much improved the condition of the wound.
On the third of January 1823, 1 extracted another cartilage from the opening over the sternum, an inch and a half long ; and on the fourth another, two inches and a half in length, an inch broad at one end, and narrowing to less than half an inch at the other. This must have been the ensiform cartilage of the sternum. After this the sinus closed, and there was no return of inflammation.
From the month of April 1823, at which time he had so far recovered as to be able to walk about and do light work, enjoying his usual good appetite and digestion, he continued with me, rapidly regaining his health and strength.
By the 6th of June 1 823, one year from the time of the accident, the injured parts were all sound, and firmly cicatrized, with the exception of the aperture in the sto* mach and side. This continued much in the same situ- ation as it was six weeks after the wound was received. The perforation was about two and a half inches in cir- cumference, and the food and drinks constantly exuded, unless prevented by a tent, compress and bandage.
From this time he continued gradually to improve in
16 CASE OF ALEXIS ST MARTIN.
health and strength, and the newly formed integuments over the wound became firmer and firmer. At the point where the lacerated edges of the muscular coat of the stomach and intercostal muscles met and united with the cutis vera, the cuticle of the external surface and the mucous membrane of the stomach approached each other very nearly. They did not unite, like those of the lips, nose, &c. but left an intermediate marginal space, of ap- preciable breadth, completely surrounding the aperture. This space is about a line wide ; and the cutis and ner- vous papillae are unprotected, as sensible and irritable as a blistered surface abraded of the cuticle. This condi- tion of the aperture still continues, and constitutes the principal and almost only cause of pain or distress expe- rienced from the continuance of the aperture, the intro- duction of instruments, &c. in the experiments, or the exudation of fluids from the gastric cavity.
Frequent dressings with soft compresses and bandages were necessarily applied, to relieve his suffering and retain his food and drinks, until the winter of 1 823-4. At this time, a small fold or doubling of the coats of the stomach appeared forming at the superior margin of the orifice, slightly protruding, and increasing till it filled the aper- ture, so as to supersede the necessity for the compress and bandage for retaining the contents of the stomach. This valvular formation adapted itself to the accidental orifice, so as completely to prevent the efflux of the gas- tric contents when the stomach was fu'l, but was easily depressed with the finger.
CASE OF ALEXIS ST MARTIN,
17
'' I'he annexed wood-cut represents the ordinary appear- ance which the wound then presented, the aperture being
filled with the valve. A A A A indicate the circumference and edge of the aperture, within which the valve is seen. B shews the attachment of the latter to the upper part of the aperture. C, the nipple. D, the anterior portion of the breast. E, the scar where the opening was made with the scalpel, and the cartilages taken out. FFFF, cicatrix of the original wound around the aperture.
In the spring of 1824 he had perfectly recovered his natural health and strength; the aperture remained;
18 CASE OF ALEXIS ST MARTIN.
and the surrounding wound was firmly cicatrized to its edges.
In the month of May 1 825, 1 commenced my first se- ries of gastric experiments with him, at Fort Mackinac? Michigan Territory. In the month of June following, I was ordered to Fort Niagara, N. Y. where, taking the man with me, I continued my experiments until August. Part of these experiments were published in 1826, in the 29th number of the Philadelphia " Medical Recorder," conducted by Doctor Samuel Calhoun. About this time (August 1825), I took St Martin with me to Burlington, Vermont, and from thence to Plattsburgh, New York. From the latter place he returned to Canada, his native place, without obtaining my consent.
Being unable to ascertain the place of his resort, I gave him up as a lost subject for physiological experiments, and returned to my post at the west again. I did not, however, remit my efforts to obtain information of his place of residence and condition.
He remained in Canada four years, during which pe- riod he married, and became the father of two children ; worked hard to support his family ; and enjoyed robust health and strength. In 1825, as he has informed me, he engaged with the Hudson Bay Fur Company, as a voyageur to the Indian country. He went out in 1827, and returned in 1828 ; and subsequently laboured hard to support his family until 1829.
Accidentally learning about this time where he was, and that he enjoyed perfect health, I made arrangements
CASE OF ALEXIS ST MARTIN.
19
with the agents of the American Fur Company, who an- nually visit Canada for the purpose of procuring voyageurs, to find and engage him for my service, if practicable. After considerable difficulty, and at great expense to me, they succeeded hi engaging him, and transported him from Lower Canada, with his wife and two children, to me, at Fort Crawford, Prairie du Chien, Upper Missis- sippi, a distance of nearly two thousand miles, in August 1829. His stomach and side were in a similar condition as when he left me in 1825. The aperture was open, and his health good.
The appearance which is presented when the valve was pushed back is shewn in the above figure.
AAA, are the edges of the aperture. B indicates the cavity of the stomach as seen when the valve is depressed. C, the valve itself. EEE, the cicatrix of the original wound. F, the nipple.
20 CASE OF ALEXIS ST MARTIN.
He now entered my service, and I commenced another series of experiments on the stomach and' gastric fluids? and continued them, interruptedly, until March 1831*;> During this time, in the intervals of experimenting, he performed all the duties of a common servant, chopping wood, carrying burthens, &c, with little or no suffering or inconvenience from his wound. He laboured constantly, became the father of more children, and enjoyed as good health and as much vigour as men in general. He sub- sisted on crude food, in abundant quantities, except when on prescribed diet, for particular experimental purposes, and under special observance.
In the spring of 1831, circumstances made it expedient for him to return with his fgimily from Prairie du Chien to Lower Canada again. I relinquished his engagements to me for the time, on a promise that he would return when required, and gave him an outfit for himself, wife, and children. They started in an open canoe, via the Mississippi, passing by St Louis, Mo. ; ascended the Ohio river ; then crossed the state of Ohio, to the Lakes ; and descended the Erie, Ontario, and the River St Law- rence, to Montreal, where they arrived in June. He re- mained in Canada with his family until October 1832, in good health, and at hard labour. He was in the midst of the cholera epidemic, at the time it prevailed, and passed through Canada, and withstood its ravages with impunity, while hundreds around him fell sacrifices to its fatal influence. •
In November 1832, he again engaged himself to me
■CASE OF ALEXIS ST MARTIN. 21
for twelve months, for the express purpose of submitting to another series of experiments. He joined me at Plattsburgh, N. Y., and travelled with me to the city of Washington, where, with the facilities afforded by ihe head of the Medical Department, the experiments were continued upon him from November 1832, to March 1833. During the whole of these periods, from the spring of 1824 to the present time, he has enjoyed general good _ health, and perhaps suffered much less predisposition to disease than is common to men of his age and circum- stances in life. He has been active, athletic and vigo- rous ; exercising, eating and drinJcing like other healthy and active people. For the last four months, he has been unusually plethoric and robust, though constantly sub- jected to a continued series of experiments on the inte- rior of the stomach ; allowing to be introduced or taken out at the aperture different kinds of food, drinks, elastic catheters, thermometer tubes, gastric juice, chyme, &c. almost daily, and sometimes hourly.
Such have been this man's condition and circumstan- ces for several years past ; and he now enjoys the most perfect health and constitutipnal soundness, with every function of the system in full force and vigour. , ,
Mode of extracting the Gastric Juice. — The usual me- thod of extracting the gastric juice, for experiment, is by placing the subject on his right side, depressing the . valve within the aperture, introducing a gum-elastic tube, of the size of a large quill, five or six inches into the sto-
22 CASE OF ALEXIS ST MARTIN.
mach, and then turning him on the left side, until the orifice becomes dependent. In health, and when free from food, the stomach is usually entirely empty, and contracted upon itself. On introducing the tube, the fluid soon begins to flow, first hydrops, then in an inter- rupted, and sometimes in a short continuous stream. Moving the tube about, up and down, or backwards and forwards, increases the discharge. The quantity of fluid ordinarily obtained is from four drachms to one and a half or two ounces, varying with the circumstances and con- dition of the stomach. Its extraction is generally attend- ed by that peculiar sensation at the pit of the stomach, termed sinking, with some degree of faintness, which ren- ders it necessary to stop the operation. The usual time of extracting the juice is early in the morning, before he has eaten, when the stomach is empty and clean.
On laying him horizontally on his back, pressing the hand upon the hepatic region, agitating a little, and at the same time turning him to the left side, bright yellow bile appears to flow freely through the pylorus, and passes out through the tube. Sometimes it is found mixed with the gastric juice, without this operation. This is, however, sel- dom the case, unless it has been excited by some other cause.
The chymous fluids are easily taken out by depressing the valve within the aperture, laying the hand over the lower part of the stomach, shaking a little, and pressing upwards. In this manner, any quantity necessary for ex- amination and experiment can be obtained.
CASE-OF ALEXIS ST MARTIN. 23
Valve. — The valve mentioned above, is formed by a slightly inverted portion of the inner coats of the stomach fitted exactly to fill the aperture. Its principal and most external attachment is at the upper and posterior edge of the opening. Its free portion hangs pendulous, and fills the aperture when the stomach is full, and plays up and down, simultaneously with the respiratory muscles, when empty.
On pressing down the valve when the stomach is full, the contents flow out copiously. When the stomach is nearly empty, and quiescent, the interior of the cavity may be examined to the depth of five or six inches, if kept distended by artificial means ; and the food and drinks may be seen entering it, if swallowed at this time, through the ring of the oesophagus. The perforation through the walls of the stomach is about three inches to the left of the cardia, near the left superior ter- mination of the great curvature. When entirely empty, the stomach contracts upon itself, and sometimes forces the valve through the orifice, together with an additional portion of the mucous membrane, which becomes com- pletely inverted, and forms a tumour as large as a hen's egg. After lying on the left side, and sleeping a few- hours, a still larger portion protrudes, and spreads out over the external integuments, five or six inches in cir- cumference, fairly exhibiting the natural rugge, villous membrane, and mucous coat, lining the gastric cavity. This appearance is almost invariably exhibited in the morning, before rising from his bed.
( 24 )
CHAPTER II.
OF ALIMENT.
Man an omnivorous animal — Nature of animal food — The ulti- mate principles of aliment the same, whether deriA^ed from animals or vegetables — The action of the stomach on food always the same — The quantity of nutriment required varies according to circumstances — The quality is also important — Variety is required — Table of digestibility of various sub- stances— Animal more quickly digested than vegetable food — Minuteness of division influential on digestion — Fish easily digested — Condiments not essential — Drink necessary — Effect of Wine — Quantity more influential than quality.
Man is said to be an omnivorous animal, destined to procure his food from both the animal and vegetable kingdoms. The inhabitant of temperate climates is unquestionably so. It would be interesting to ascertain by experiment whether he would be sustained by habit from infancy, on the productions of either of these grand divisions. If the result should be favourable to the de- monstration of this proposition, though it might stiU more unsettle the opinions of physiologists, it would be an evi- dence of this truth, that man is a creature of habit and circumstance, carrying about him the effects of primeval disobedience, destined not only to earn his food by his own exertions, but to partake of such as the climate in which he resides may supply to him. Approximating to this are the habits of people of different quarters of the world — those of Asia, who live almost exclusively on ve-
NATURE OF ANIMAL FOOD. 25
getable and farinaceous food, and those of the northern regions of America, who derive their food principally from fish, oil, and flesh.
.Other substances have sometimes been used as aliment: and Professor Dunglison mentions, on the authority of Humboldt, that the Ottomaques, a tribe of Indians of South America, are in the habit of using " an unctuous earth, or a species of pipe-clay,'" as an article of diet. Whether nutriment can be supplied by such articles alone, is extremely problematical. In all countries, some persons are found who are in the constant habit of eating large quantities of clay, chalk, slate, stone, &c. Such practices may be regarded as evidence, if not of a diseased, at least of a vitiated appetite ; though it often happens that alkaline and absorbent substances are used medicinally with advantage, particularly where much aci- dity of the stomach prevails.
As it respects the inhabitants of Europe and their American descendants, as well as most other natives of temperate climates, it is well known that they derive their nourishment from both the animal and vegetable kingdoms.
The facility of digestion of different articles of -diet, and the quantity of nutrient principles which they con- tain, have been subjects of some discrepance of opinion among physiologists. They have, however, settled down into a belief, probably as near the truth as practicable, that animal food is more readily assimilated, and affords
26 NATURE OF ANIMAL FOOD.
more nutrition in a given quantity, than vegetable or farinaceous food.
Animal food has been divided into fibrine, gelatine, and albumen, and a comparison drawn between their de- grees of digestibility. But it will occur to every one at all acquainted with the subject, that almost every portion of animal food contains an admixture of all these princi- ples, and it is consequently very difficult to come to a correct conclusion. The truth is, there can be no gene- ral rule on this subject. The facility of digestion is mo- dified by so many circumstances, as health, disease, idio- syncracy, habit, and preparation of food, that a rule which would apply in one case would be incorrect in another. It depends more upon other distinctions than upon those relating to the chemical composition of the food. Albu- men (one of these chemical divisions), if taken into the stomach, either very slightly or not at all coagulated, is perhaps as rapidly chymified as any article of diet we possess. If perfectly formed into hard coagulse, by heat or otherTvise, and swallowed in large solid pieces, it experi- ences a very protracted digestion. The reason is obvi- ous. In the first case, the albumen becomes finely coa- gulated, and divided in the stomach ; in the second, it is less susceptible of subdivision from its hardness. Fibrine and gelatine are affected in the same way. If tender and finely divided, they are disposed of readily ; if in large and solid masses, digestion is proportionably retarded. Minuteness of division and tenderness of fibre are the two grand essentials for speedy and easy digestion. By re-
- ULTIMATE PRINCIPLES OF NUTRIMENT. 27
ferring to my experiments, it will be seen that those ar- ticles of diet which were submitted to the action of the gastric juice, either artificially when out of the stomach, or in the stomach by natural process, were dissolved in proportion to the fineness of their division or their soli- dity— the one rapidly, and the other slowly.
The digestion of animal and vegetable diet requires the same process, though one may afford a larger pro- portion of the nutrient principle than the other. Gene- rally speaking, vegetable aliment requires more time, and probably greater powers of the gastric organs, than ani- mal. Its digestibility is, however, dependent upon the same laws as those that govern the solution of animal food ; and it is facilitated by division and tender- ness.
The ultimate principles of nutriment are probably al- ways the same, whether obtained fi'om animal or vege- table diet. It was said by Hippocrates, that " there are many kinds of aliments, but that there is at the same time but one aliment." This opinion has been contested by most modern physiologists ; but I see no reason for scepticism on this subject. Some imperfect experiments which I instituted on the operations of the hepatic and pancreatic juices, and which will be found in a subse- quent part of this volume, tend to throw some light on the subject. Chyme was submitted to the action of these fluids, and they invariably produced similai' effects A fluid was separated, varying slightly in colour, but of the same apparent consistence and identity ; and was increased
28 ACTION OF THE STOMACH ON FOOD*
or lessened in proportion to the quality of the food of which the chyme was formed. Whether this fluid was or was not imperfectly formed chyle, is a matter of opi- nion only. The circulating fluids of the system are al- ways nearly the same in health, and that which goes to supply and replenish them, should consequently possess the same invariable properties. Chyle, after its separa- tion in the intestines, is probably further changed and perfected by the action of the lacteal absorbents and sanguiferous vessels, before it is completely assimilated. Chyme, from which this nutrient principle is obtained, is a compound of gastric juice and aliment. It may be re- garded as a gastrite of whatever it is combined with, va- ried according to the kind of aliment used. The perfect chyle, or assimilated nutriment, probably contains the elements of all the secretions of the system ; such as bone, muscle, mucus, saliva, gastric juice, &c. &c., which are separated by the action of the glands, the sanguife- rous and other vessels of the system.
The action of the stomach, and its fluids, on aliment, is believed to be sui generis, invariably the same, in health, on all kinds. And yet it is contended by Paris, and obliquely hinted by some other modern physiologists, that as animal food " possesses a composition analogous to that of the structure it is designed to supply," it " re- quires little more than division and depuration," &c. It is singular that sensible men, and men of science, can allow themselves to be led to such erroneous conclusions, and w^ill not perceive a simplicity and uniformity in the
ACTION OF THE STOMACH ON FOOD. 2Q
process of digestion, as well as in all the other operations of nature. That the active solvent of the stomach should produce the same effect on all alimentary substances, is no more wonderful than that caloric should liquefy all kinds of matter. In both cases it only requires a longer or shorter continuance, or more or less concentrated ac- tion, of the agent, to produce the same effect. If animal food is only to be divided and depurated, blood, which is an elementary part of the body, would require no change in the stomach. But it is perfectly idle to talk in this way. The most innutritious vegetable and the most ani- malized substance, require the same action of the gastric solvent, as the reader will find amply demonstrated in the following experiments. It is true that one may be dis- posed of with ease, and the other with difficulty ; but this is not always, nor indeed often, in a direct ratio to their respective proportions of nutrient principles. An innu- tritious diet may be disposed of as easily, the circum- stances of divisibility and tenderness of fibre being equal, as a nutritious one. I do not believe that the one re- quires a more " complicated series of decompositions and recompositions " than the other ; nor that the chyle from animal aliment is more highly " animalized" than that from the poorest diet we possess. The " digestive fever," or the excitement that follows the digestion of animal food, is the effect, not of a different kind of stimulus, but of the introduction of a greater quantity of chyle, or the nutritive principle of food, into the circulating fluids. It excites the system precisely in the same manner as ardent
38 QUALITY OF NUTRIMENT REQUIRED.
spirits, or other stimulus does, with the exception, that its effects are more permanent.
The quantity of nutriment required by different indi- viduals, is as various as the individuals who partake of it. As a general rule, it may be said that persons who do not exercise much, require less nutritious diet than those who are in the habit of constant labour. What would be a natural supply in one, would be excess in another. With labouring persons, much of the excess is carried off by perspiration ; and probably a great deal of nervous energy is wasted by laborious occupations, which re- quires to be replenished by the nutrient principles of aliment. This is a subject, however, on which we can only offer conjecture ; for it is difficult to argue on a point of which we know so little. Young people who are grow- ing, require more nutriment in proportion to their size, than those who have arrived at adult age.*
The quality of nutriment is a matter of considerable importance in dietetic regulations. Bulk is, perhaps,
* The rapidity and extent of waste occurring under certain cir- cumstances, have been ably exhibited by Dr Southwood Smith in the second volume of his Philosophy of Health (p. 393). Dr Smith weighed eight of the men employed in feeding the fires of the Phoenix Gas Company in London, before they began and after finishing their work, which latter lasted one hour. The tempera- ture of the atmosphere at the time was 60*', and the barometer stood at 29.25. The loss sustained during that short time amount- ed to 2 lb. 8 oz. in the lowest of the eight, and to no less than 41b. 3oz. in the highest. The general result was, that the men employed in that work lost from 2 lb. to 5 lb weight twice a-day by perspiration alone. In extreme cases like these, the necessity of a proportionately large supply is self-evident; without it the men would perish in a week. — Editor.
KINDS OF NUTRIMENT. 31
nearly as necessary to the articles of diet as the nutrient principle. They should be so managed that one shall be in proportion to the other. Too highly nutritive diet is probably as fatal to the prolongation of life and health, as that which contains an insufficient quantity of nutri- ment. It has been ascertained that carnivorous animals will not live on highly concentrated food alone. Dogs fed on oil or sugar, which are both converted by the digestive organs almost entirely into chyle, are found to become diseased, and die in a few weeks. The inference drawn by Paris,* that it merely " proves that an animal cannot be supported on highly concentrated aliment alone," no doubt, is a correct one ; though opposed to the opinion of Magendie, the author of the experiments, who infers that death proceeds from the want of azote in these articles of diet, and that life cannot be supported on non-azotized aliment.j
* Paris on Diet, p. 72.
•j- It seems to me that animals die when confined exclusively to the use of concentrated food, not from the want of azote, but sim- ply from such food being out of harmony with their organic struc- ture. The Creator has constituted every animal with relation to its natural or proper food and no other, and if that be denied it, it must of necessity suffer. The cow, for example, has four stomachs specially adapted for digesting herbage, out of which it extracts its nutriment ; but supposing that, by a chemical process, we were able to extract the nutritive essence from the grass or hay, and were to give it in a concentrated state to the cow, can any reason- able being even fancy that the cow would thrive as well as when it had the pleasure of cropping the grass for itself, and employing its own stomachs to effect the preparation ? The thing is absurd, and we may be equally certain, that if the stomach and intestines of any animal are constructed by the Creator for the reception of
32 DIGESTIBILITY OF DIFFERENT
The following articles of the materia alimentaria have, in the course of these experiments, been submitted to the action of the stomach and the gastric fluids. I have attempt- ed, in this table, to approximate towards a comparison of the digestibility of the several articles there mentioned. Precision, as to minutes, has not been attended to. When digestion has been accomplished two or three minutes either before or after a certain number of hours and quar- ters, I have set down the quarter to which it approached the nearest.
In a subsequent part of this volume, a more particular and minute detail will be found, both of natural and arti- ficial digestion.
a mixed and bulky diet, that animal cannot thrive on pure and concentrated food. Magendie evidently overshoots the mark when he seeks for the explanation in the supposed absence of a single chemical principle. — Editor^
KINDS OF ALIMENT.
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36 DIGESTIBILITY OF DIFFERENT SUBSTANCES.
This table is far from being complete. The experi- ments from which it has been formed, were made princi- pally with the view of demonstrating other important principles connected with the subject of digestion. The only way of ensuring minuteness and accuracy as to the comparative digestibility of different kinds of diet, would be to try the effect of the gastric juice, in a series of ex- periments, first on one article of diet, and then on an- other, repeating and adapting them to meet all the va- rious conditions of the stomach, and the vicissitudes and irregularities of the system, until the whole range should be completed — a Herculean task, which it would take years to accomplish. In the above table, the time is counted from the reception of the meal of various arti- cles to the chymification of the v^hole : hence the con- clusions are frequently indefinite, some of the articles being sooner disposed of than others. For instance, if a dinner be eat of venison steak and fat pork, the time of digestion of the whole quantity would, in all probability, be twice as long as if venison had been used alone. Oily substances are digested with great difficulty, and the fat of all meats is converted into oil in the stomach before it is digested. Chymification is most readily effected en solid food, or rather on a soft solid, which is easily divi- sible into shreds or small particles. Such is particularly the character of venison, which is ascertained to be one of the most digestible of substances. The qualities of looseness of texture and susceptibility of division belong to most of those wild meats and game which are gene-
VEGETABLES ARE DIGESTED SLOWLY. o/
rally acknowledged to be easy of digestion. Beef and mutton, of a certain age, possess similar qualities. '"'
The opinion advanced by Paris, | that the flesh of wild animals is more dense than the domesticated, does not correspond with the experience of those who are well ac- quainted with the former. Although, on making a sec- tion of wild flesh, such appearance may be indicated, yet the fibres are found to be more easily separated by mas- tication, or other force, and are generally tender ; at least, such is the case with the flesh of those animals that are considered luxurious by the epicure. Compare, for ex- ample, the flesh of the wether and the deer, animals which have a near correspondence in their habits, and the difference will be very obvious.
The digestibility of most meats is improved by inci- pient putrefaction, sufficient to render the muscular fibre slightly tender.
Vegetables are generally slower of digestion than meats and farinaceous substances, though they sometimes pass out of the stomach before them, in an undigested state. Crude vegetables, by some law of the animal economy^
* It is much to be regretted that Dr Beaumont did not make a series of experiments purposely to ascertain the relative diges- tibilities of different kinds of food. From not having attended to any of the precautions requisite to guard against error, the results above narrated can be regarded as only approximative. The ra- pidity of digestion, as the author himself shews, varies greatly ac- cording to the quantity eaten, the amount and nature of the pre- vious exercise, the interval since the preceding meal, the state of health and of the weather, and also the state of the mind. But in scarcely any of the experiments have these conditions been carefully noted Editor.
+ Paris on Diet, p. 72.
38 INFLUENCE OF MINUTE DIVISION.
not well understood, are allowed, even when the stomach is in a healthy state, sometimes to pass the pyloric orifice, while other food is retained there to receive the solvent action of the gastric juice. This may depend upon their comparative indigestibility ; for it is well known that ca- thartic medicines, various fruits, seeds, &c. which operate as laxatives, are not digested ; are incapable of being re- tained in the stomach ; and pass rapidly through the in- testinal tube. When such articles are in excess, they produce considerable derangement, and sometimes fatal consequences.
Vegetable, like animal substances, are more capable of digestion in proportion to the minuteness of their di- vision, as I have before remarked, provided they are of a soft solid ; and I cannot, therefore, concur in the opinion expressed by Paris, '^ that potatoes are better when only boiled so as to be rendered tender, and have their shape preserved, than when boiled to a " dry, insipid pow- der." They may be more palatable, and contain more nutriment ; but they are not so easily affected by the gastric solvent. The difference is quite obvious on sub- mitting parcels of this vegetable, in different] states of preparation, to the operation of the gastric juice, either in the stomach or out of it. Boiled, or otherwise cooked to dryness, so as to be easily mashed, potatoes very rea- dily become reduced to a chymous state, when submitted to the action of the gastric juice. When differently pre- pared, and only boiled so as to be rendered barely soft, moist and tenacious, with the shape preserved, entire pieces * Paris on Diet, p. 75.
SOLID FOOD DIGESTS QUICKER THAN FLUID. 39
remain long undissolved in the stomach, and very slowly yield to the action of the gastric juice in vials on the bath. Pieces of raw potato, when submitted to the operation of this fluid, in the same manner, almost en- tirely resist its action. Many hours elapse before the slightest appearance of digestion is observable, and this only upon the surface, where the external laminae become a little softened, mucilaginous, and slightly farinaceous. Every physician, who has had much practice in the dis- eases of children, knows that partially boiled potatoes, when not sufficiently masticated (which is always the case wdth children), are frequently a source of colics and bowel complaints, and that large pieces of this vegetable pass the bowels untouched by digestion.
These remarks will apply, also, to most other vegetable aliment.
The varieties of fish, which are generally used by the citizens of this country, may be regarded as easily sus- ceptible of digestion. The lobster, crab, and some others of the testaceous tribe, are, perhaps, exceptions.
Solid food is sooner disposed of by the stomach than fluid, and its nutritive principles are sooner carried into the circulation. It has been observed, however, that the exhaustion from abstinence is quicker removed by liquid than solid aliment. This is undoubtedly true ; and it may be accounted for on the ground of a general sym- pathy existing between the stomach and all the other parts of the body.* It is only necessary, in proof of this
* The proper explanation of this fact seems to be the rapid absorption into the system of a part of the liquid aliment, and the
40 DRINKS ESSENTIAL.
fact, to appeal to the experience of almost every physi- cian. The violent spasms, contortions, &c. affecting dif- ferent and remote parts of the system, that sometimes supervene on the introduction of crude or indigestible food into the stomach, are pretty clear indications of the powerful sympathy that exists between it and other or- gans or apparatuses.
Condiments, particularly those of the spicy kind, are non-essential to the process of digestion, in a healthy state of the system. They afford no nutrition. Though they may assist the action of a debilitated stomach for a time, their continual use never fails to produce an indirect de- bility of that organ. They affect it as alcohol or other sti- mulants do — the present relief afforded is at the expense of future suflPering. Salt and vinegar are exceptions, and are not obnoxious to this charge, when used in moderation. They both assist in digestion — vinegar, by rendering mus- cular fibre more tender — and both together by producing a fluid having some analogy to the gastric juice.
Drinks are nearly as essential to the animal system as the more substantial food. Though not subject to diges- tion, they enter into the circulation, and become import- ant agents in the ultimate changes that are undergoing in the tissues of the organism. Simple water is, perhaps, the only fluid that is called for by the wants of the eco- nomy. The artificial drinks are probably all more or less
support which it consequently gives almost immediately. Vv^hereas if the whole of the aliment be solid, it must undergo digestion before any of it can be absorbed, and this requires much time. ■ The author himself proves that the absorption of the fluid part of soup begins almost immediately after it is swallowed. — Editor.
DRINKS ESSENTIAL. 41
injurious ; some more so than others ; but none can claim exemption from the general charge. Even coffee and tea, the common beverages of all classes of people, have a ten- dency to debilitate the digestive organs. Let any one who is in the habit of drinking either of these articles in a weak decoction, take two or three cups made very strong, and he will soon be aware of their injurious tendency. And this is only an addition to the strength of the narcotic he is in the constant habit of using.* The whole class of alcoholic liquors, whether simply fermented or distilled, may be considered as narcotics^ producing very little diffe- rence in their ultimate effects on the system.
The injury which a constant use of wine is known to produce on some stomachs, has been sometimes attributed to the small quantity of tartaric acid which it contains. But it is not the cream of tartar that renders wine so de- leterious to many stomachs. It is the acidity produced by the acetous fermentation of the saccharine matter con- tained in the wine, aided, perhaps, by the alcohol which is in a state of combination with it. Beer has the same effect on the same idiosyncracies, or diseased states of the stomach. Besides, both of these fluids are in a partial stage of acetous fermentation, which is consummated by the increase of temperature in the stomach.
* Agreeing with the author on the general opinions expressed in the text, I must diifer from him as to the soundness of the ar- gument founded on strong tea and coffee. His statement merely proves that too much is badx Beef and mutton are in themselves very good, but too much of them is hurtful. Are we therefore to proscribe them ? Weak tea may be good although " very strong''' tea is pernicious. I concur, however, in thinking, that tea, cof- fee, and stimulants are grossly abused. — Editor.
D
42 . WHAT IS THE BEST KIND OF DIET.
It would be a task of great difficulty to designate the exact kind of diet that would, if generally adopted, be the most conducive to health and longevity. A considerable variety seems to be necessary to man, in a state of civili- zation. This want of variety is induced by long habit, which it would probably be unsafe to break through. Whe- ther man was originally carnivorous or granivorous, is a question which we cannot solve, and perhaps it it not worth the attempt ; at present he is both, and with his present mode of existence we have to do.*
The quantity of aliment is probably of more importance than the quality^ to ensure health. The system requires much less than is generally supplied to it. The stomach disposes of a definite quantity. If more be taken than the actual wants of the economy require, the residue remains in the stomach, and becomes a source of irritation, and produces a consequent aberration of function, or passes into the lower bowels in an undigested state, and ex- tends to them its deleterious influence. Dyspepsia is oftener the effect of over-eating and over-drinking than of any other cause.
* It would be a mere waste of time to lay down any exact diet for general adoption. Men differ so much from each other, and in their employments, ages, and modes of life, and the same indi- vidual differs so much at different times even from himself, as to render an invariable rule a sheer absurdity..^ — Editor.
( 43 )
CHAPTER III.
OF HUNGER AND THIRST.
Hunger— Its exciting cause— Different theories of— The Author's theory of hunger— Thirst and its causes— Objections to the Author's theory of hunger.
Hunger is a painful sensation, referred to the region of the stomach. It is a kind provision of nature, designed to remind man, and other animated beings, of the neces- sity of replenishing the wastes of the system, as well as contributing to its growth. Much inquiry has been made on this subject, and many theories have been given to account for the phenomenon. It has been supposed by some, that the friction of the internal coats of the empty stomach was the cause of the sensation. This opinion is liable to several objections : — 1st, A healthy stomach di- gests its contents in from one to three or four hours, and hunger is not usually experienced until some time after the latter period. If hunger be the effect of the friction of the p^rietes of the stomach, it ought to be experienced the moment that that organ has disposed of its contents. 2d, In nausea and vomiting, the stomach is brought into a situation, according to this theory, to experience the sensation of hunger ; and yet we know how opposed it is to receiving any thing like food. 3d, In gastritis and fevers the sensation hardly ever occurs, though very lit-
44 EXCITING CAUSE OF HUNGER.
tie food shall have occupied the stomach for a long time — perhaps not for weeks. This organ, under such cir- cumstances, is generally empty and irritable, yet the pe- culiar sensation in question hardly ever supervenes. Be- sides, hunger sometimes occurs when the stomach is par- tially or wholly filled. The potation of spirits or brandy and water, and some other indigestible substances of a liquid character, does not remove the sensation, although by this means the parietes of the stomach are as com- pletely separated as by food.
It has also been suggested that the sensation of hun- ger is produced by the irritation of a quantity of gastric juice in the stomach, which, by its stimulus, excites the feeling. The principal objection to this doctrine is based upon the fact, that the stomach contains no gastric juice, or, at any rate, but a very small quantity, in its empty state, or when aliment or other irritant is not present. Besides, if it were true that it contained a quantity of the fluid, such fluid does not possess the power of producing any thing like irritation or inflammation of its coats. It is as innoxious to the stomach as the blandest substance in nature. It exerts its influence on free aliment, but not on the living fibre.
By referring the sensation to " an energetic state of the gastric nerves, occasioned by an interval of inactivity, during which the vital powers may be supposed to accu- mulate," * it appears to me that we are venturing upon unexplored grounds, of which we know but little. We are not accustomed to call those painful nervous sensa-
* Paris on Diet, p. 55.
EXCITING CAUSE OF HUNGER. . 45
tions to which the system is sometimes subject, states of high nervous energy. Are they not rather states of ner- vous debility ? or, at any rate, irregular and unhealthy motions ?
That the introduction of narcotics into the stomach should destroy the appetite, proves only that they have the same effect oh that organ as they have on other parts of the body ; they paralyse the nerves, and render them incapable of being the media of communication to their common centre.
Many other causes have been assigned for this sensa- tion, equally wide, probably of the true one. It has been attributed to the "foresight of the vital principle," a phrase that means any thing, every thing, or nothing, ac- cording to the construction which each one may put upon it. Such explanations conduce nothing to the promotion of science. They are mere sounds and words, which in- geniously convey a tacit acknowledgment of their author's ignorance.
Again, the mechanical action of the liver upon the diaphragm, has been accused of producing the sensation of hunger. Some proof, more than mere assertion, is necessary to convince honest inquirers that so remote a cause should produce such effects on the stomach, the immediate seat of the feeling. Of the same nature, is the opinion of the fatigue of the contracted fibres of the stomach, or of compression of the nerves of that organ, &c. &c.
Magendie, convinced that all the theories on this sub- ject were unsatisfactory, comes to the following compre-
46 THEORY OF HUNGER.
hensive conclusion, that " Hunger is produced like all other internal sensations, by the action of the nervous system, and it has no other seat than in this system it- self, and no other causes than the general laws of organi- zation."* I cannot perceive that such explanations bring the mind to any satisfactory understanding of the sub- ject. In such broad propositions, it is difficult to ascer- tain the exact meaning. If the design is to convey the impression that hunger has no " local habitation ;" that it is an impression, affecting all the nerves of the system inr the same manner ; then the sensation would be as likely to be referred to one organ as another. It is true, that without nervous communication there would be no sensation at all. This applies as well to other parts as to the stomach. The nerves are the media of communica- tion from the sensible parts to the centre of perceptions. They warn the encephalon not only of the injuries, but of the wants of the tissues. We are accustomed to refer local sensations and irritations to the parts apparently affected — desire for urination and defecation, to the blad- der and rectum ; for liquids, to dryness of the mouth and fauces : and we account, in like manner, for other physi- ological and pathological sensations. When we can ar- rive at the exact interpretation of an author, who says that hunger has " no other causes than the general laws of organization," it will then be time to give reasons for an assent to or dissent from the proposition.
This subject is, unquestionably, involved in considera- ble doubt and obscurity, and will not, it is to be appre- * Summary of Physiology, p. 1 %^.
THE author's theory OF HUNGER. 47
hended, admit of a very speedy elucidation. The Author of Nature is perfect in all His works ; and although we may not understand all the operations of His hands, we are compelled to acknowledge their wisdom, propriety, and beauty. Man would be miserable and wretched in- deed, if he depended solely on his own discretion and judgment to decide upon the quantity and quality of ali- ment necessary to supply the wastes, and administer to the growth, of the system. This paucity of judgment and discretion is, however, more than compensated by an irresistible sensation, which indicates the proper time for the reception of food. The immediate cause of this sen- sation, as we have seen, has not as yet received a very satisfactory explanation, and perhaps will not admit of one. But, although confessedly obscure, we are not denied the privilege of patient investigation, and perse- vering search after truth. Knowledge is progressive, as well in this as every other science ; and every new dis- covery, and every rational hypothesis, are additions to the general stock. Persuaded of the truth of these ge- neral propositions, and anxious mainly to elicit investiga- tion on the subject, I submit the following Theory of Hunger, believing it to be as reasonable, to say the least, as any that has been propagated.
My impression is, that the sensation of hunger is pro- duced by a distention of the gastric vessels, or that ap- paratus, whether vascular or glandular, which secretes the gastric juice ; and is believed to be the effect of re- pletion by this fluid.
One reason, among others, for this belief, is the estab-
48 THEORY OF HUiNGER.
lished fact, that the internal sensations referred to dif- ferent organs, as has been previously alluded to, are caused by some modified action or condition of the parts in the tissues of the organ itself. The modification in the parts to which the sense of hunger is invariably re- ferred, I conceive to be a distention, by the gastric juice, of a particular set of vessels or glands, constituting in part the erectile tissue of the villous coat of the stomach. The sensation varies according to the different degrees or states of distention, fi-om the simplest desire to the most painful sense of hunger ; and is allayed or increased in proportion to the application, or refusal, of alimentary stimulus to the excretory vessels. The greater the dis-_ tention of the vessels, the more acute will be the pain : hence the difference between a short and protracted fast. Appetite and hunger belong to the same class of sensa- tions ; they differ only in degree. In this they are like all other sensations. A little increased circulation in the vessels of the brain produces peculiarly vivid, but not absolutely unpleasant feelings, and gives force and ener- gy to the mental volitions : carried further, it produces most painful sensations. It is unnecessary to cite fur- ther examples. Indeed, it does not need arguments to prove what is the subject of every day's observation. It is well known that the pain from acute inflammation is produced by distention of the blood-vessels. Let any one, who is disposed to try the effect of vascular disten- tion, place a ligature around the finger or arm sufficiently tight to retard the returning blood, and the truth will be sufficiently obvious.
THEORY OF HUNGER. 49
It is, therefore, inferred from the pain (and no one, it is believed, will deny that hunger is a painful sensation, whatever may be his opinion of appetite)^ that vessels of some kind are distended ; and it is demonstrated, I think, in some of the following experiments, that these are the gastric vessels. On applying aliment to the internal coat of the stomach, which, in health, is merely lubricated with mucus, innumerable minute papillae, the orifices, undoubtedly, of the gastric vessels, immediately throw out a quantity of the fluid, which mixes with the food. This effect is too sudden, and the secretion too copious, to be accounted for on the ordinary principles and laws of secreting mucous surfaces. The quiescence and re- lief from l3ie unpleasant sensation which are experienced as soon as the vessels are emptied, are, I think, additional proofs of my opinion. It is certain, that at the introduc- tion of every meal, or on the application of alimentary stimulus to the internal coat of the stomach, a very large secretion of a fluid, which has repeatedly been ascertained to be an alimentary solvent, immediately takes place ; and that when the stomach is destitute of food or some other irritating substance, no such secretion can be found in it. And it is more than probable — it, in fact, almost amounts to demonstration, that a large quantity of this fluid must be contained in appropriate vessels, during a fast, ready to obey the call of aliment. I would not be understood to say that the whole quantity necessary for an ordinary meal is eliminated from the blood, previous to the commencement of alimentation ; but that enough
E
50 NATURE OF THIRST.
is contained in the gastric vessels to produce the sensa- tion of pain or hunger.
If it be objected to this theory, that the vessels would become ruptured, or empty themselves into the cavity of the stomach, during a long fast, I reply, that this appa- ratus is probably constituted like many of the other or- gans of the system, and permits the absorption of its se- cretions by the lymphatic or other absorbent vessels. The male semen is constantly being secreted, and depo- sited in its proper seminal vessels, ready to be ejected during the venereal orgasm ; and yet how many men live for years, or perhaps for a whole life, who have no in- tercourse with the other sex. What becomes of the semen under these circumstances ? Taken up, unques- tionably, by the absorbing vessels, as the gastric juice of the stomach is.
I offer this theory for consideration, persuaded that the public will allow it such weight as it may have a right to claim : more than this, I have no wish to ask.
Thirst. — This sensation is felt in the mouth and fauces. Like hunger, it is a kind provision of Nature, designed to remind men and animals of the necessity, not of replenishing the wasting solids of the system, but of diluting the fluids that are carrying on these processes. Although Magendie has attempted to put a stop to all inquiries on this subject, in the remark, that " Thirst is an internal sensation, an instinctive sentiment ;" " the result of organization, and does not admit of any expla- nation ;" I apprehend a remote cause of this sensation
OBJECTIONS TO DR BEAUMONT's THEORY. 51
may be found in the viscidity of the blood, which requires a liquid to render it more fluid, and more susceptible of introduction into the capillaries aud secreting surfaces. The proximate cause may exist in an irritation, a kind of sub -inflammation of the mucous membranes of the mouth and fauces, the effect of the viscid state of the blood, and consequently impervious state of the secretory vessels of these membranes. The sensation of dryness, or thirst, is supposed to be the effect of evaporation, the mouth and throat being constantly exposed to the at- mosphere. When there is sufficient fluidity of the blood, the secretion is so much more copious than the evapora- tion, that a constant moisture is preserved. The sensation of thirst resides in the tissues ; and it is no more " an in- stinctive sentiment" than any other sensation of the eco- nomy. To say that it is the " result of organization," gives no explanation, amounts to nothing, and is certainly, to say the least, a very unsatisfactory way of disposing of the question.
Note by the Editor.
That the immediate exciting cause of the sensation of hunger is seated in the stomach, there can be no reason to doubt ; but the sensation itself unquestionably takes place in the brain, just as the sensation of hearing does, although in the latter case the exciting cause is an exter- nal impulse acting on the auditory nerves. Accordingly, it has been proved by Brachet that, when the nervous com- munication between the stomach and brain is cut off, the
52 OBJECTIONS TO DR BEAUMONT's THEORY,
feeling of hunger instantly ceases, even where a moment before it was ravenously strong.
It is important to observe this analogy of relation be- tween different parts performing different functions under one general law, becuase it explains many phenomena, and facilitates inquiry. The cause which excites hearing is a certain condition of the auditory nerve, arising out of its relations to the vibrations of the atmosphere and to the brain. In like manner, the cause which excites the feeling of hunger is a certain condition of the stomachic nerves, arising out of their relation to the state of the gene- ral system, and to the brain. When the system has lost much of its substance, either by severe exercise, or by an unusually long fast, the nerves of the stomach are affected in such a way as to give rise in the brain to the feeling of hunger. When, on the contrary, from a sedentary mode of life, or the shortness of the interval since last meal, there has been little expenditure of substance, the stomachic nerves in harmony with that state convey to the brain the sensation of contentment, and no appetite is felt. Hence the keen appetite of those who live actively and in the open air, and the feeble appetite of sedentary per- sons. The nerves of hearing cannot excite a feeling of sound unless the atmospherical vibrations impinge upon them ; and, in like manner, the stomachic nerves cannot excite a feeling of hunger, unless their activity is stimu- lated by the corresponding state of the system.
As, however, it is the brain in which the sensations of both hearing and hunger actually take place, it happens that if it be excited by disease, in that peculiar way which,
OBJECTIONS TO DR BEAUMONt's THEORY. 53
in health, follows only the reception of the appropriate external impression made upon the nerve, the same re- sult will ensue as if the external impression were really made, viz. — that sounds will be heard and hunger felt, when neither the ear nor the stomach have undergone any change naturally calculated to produce them. This, accordingly, often happens, and we perhaps experience craving or false hunger quite as often as we hear imaginary sounds. The same relation explains the sudden disap- pearance of appetite on the announcement of agitating news, whether of grief or joy.
Dr Beaumont himself attaches no great weight to his theory of the sensation of hunger being caused by the distention of the gastric vessels, and, in truth, it seems not to be borne out by facts. He thinks that the rapidity with which gastric juice is poured out on the introduction of food, is a proof of its previous existence in the gastric vessels ; but when we remember the equal rapidity with which saliva flows into the mouth of a hungry man, when a good roast of meat is placed before him, we shall be disposed to question the fact, — unless, indeed, we hold that the saliva was also stored up in its vessels ready for use. Besides, bad news cannot instantly empty tlie gastric vessels of their contents, and yet they dispel appetite most eiFectually. But having already discussed this subject at some length in another work, I shall not dwell upon it here, farther than to add, that the same prin- ciple applies to the explanation of thirst as of hunger.*
• See the Physiology of Digestion, considered with relation to the Principles of Dietetics, 2d edition, p. 18, et seq.
{ 54 )
CHAPTER IV.
ON SATISFACTION AND SATIETY.
Quantity of food required — Satiety not a proper guide — The first feeling of satisfaction is the true indication — Gastric juice se- creted in relation to this indication.
In the present state of civilized society, with the pro- vocatives of the cuhnary art, and the incentives of high seasoned food, brandy and wines, the temptations to ex- cess in the indulgences of the table are rather too strong to be resisted by poor human nature. It is not less the duty, however, of the watchmen on the walls to warn the city of its danger, however it may regard the premoni- tion. Let them at least clear their own skirts from the stain of unfaithfulness, whatever may be the result.
There is no subject of dietetic economy about which people err so much as that which relates to quantity. The medical profession, too, have been accessory to this error, in giving directions to dyspeptics to eat until a sense of satiety is felt. Now, this feeling, so essential to be rightly understood, never supervenes until the invalid has eaten too much, if he have an appetite, which seldom fails him. Those even who are not otherwise, predis- posed to the complaint, frequently induce a diseased state
PROPER INDICATION OF ENOUGH EATEN. 55
of the digestive organs by too free indulgence of the ap- petite. Of this fact the medical profession are, gene- rally, not sufficiently aware. Those who lead sedentary lives, and whose circumstances will permit of what is called free living, are peculiarly obnoxious to these com- plaints. But by paying particular attention to their sen- sations during the ingestion of their meals, these com- plaints may be avoided. There appears to be a sense of perfect intelligence conveyed from the stomach to the encephalic centre, which, in health, invariably dictates what quantity of aliment (responding to the sense of hun- ger, and its due satisfaction) is naturally required for the purposes of life ; and which, if noticed and properly at- tended to, would prove the most salutary monitor of health, and effectual preventive of, and restorative from, disease. It is not the sense of satiety^ for this is beyond the point of healthful indulgence, and is Nature's earliest indication of an abuse and overburthen of her powers to replenish the system. It occurs immediately previous to this, and may be known by the pleasurable sensation <di perfect satisfactio7i, ease and quiescence of body and mind. It is when the stomach says enough^ and is dis- tinguished from satiety by the difference of the sensa- tions— the former feeling enough — the latter, too much. The first is produced by the timely reception into the stomach of proper aliment, in exact proportion to the re- quirements of nature, for the perfect digestion of which, a definite quantity of gastric juice is furnished by the pro- per gastric apparatus. But to effect this most agreeable of all sensations and conditions — the real Elysian satisfac-
56 SATIETY A SIGN OP EXCESS.
tion of the reasonable epicure — timely attention must be paid to the preliminary processes, such as thorough mas- tication, and moderate or slow deglutition. These are indispensable to the due and natural supply of the sto- mach, at the stated periods of alimentation j for if food be swallowed too fast, *and pass into the stomach imper- fectly masticated, too much is received in a short time, and in too imperfect a state of preparation, to be disposed of by the gastric juice.
The quantity of gastric juice either contained in its proper vessels, or in a state of preparation in the circu- lating fluids, is believed to be in exact proportion to the proper quantity of aliment required for the due supply of the system. If a more than ordinary quantity of food be taken, a part of it will be left undissolved in the stomach, and produce the usual unpleasant symptoms of indiges- tion. But if the ingestion of a large quantity be in pro- portion to the calls of nature, which sometimes happens after an unusual abstinence, it is probable that more than the usual supply of gastric juice is furnished ; in which case the apparent excess is in exact ratio to the require- ments of the economy ; and never fails to produce a sense of quiescent gratification, and healthful enjoyment. A great deal depends upon habit, in this respect. Our wes- tern Indians, who frequently undergo long abstinences from food, eat enormous quantities, when they can pro- cure it, with impunity.*
* If the principle announced in the above paragraph, that th quantity of gastric juice secreted is always in exact proportion to the proper quantity of aliment required by the system, could be
SATIETY A SIGN OF EXCESS. ^ 57
Satiety is produced by tendering too much at once for the wants of the economy ; more than the gastric juice is able to dispose of at the time ; distending the muscular fibres beyond that point so admirably fixed, by the inva- riable and universal laws of the animal system, for agree- able sensations ; disturbing the peculiarly pleasurable, undulatory motions of the rugae of the stomach, in their operations of forming chyme ; and perhaps interrupting, if not diminishing, the secretion of the gastric juice. The redundant aliment, incapable of being dissolved, for want of sufficient gastric juice, remains, and becomes a source of irritation, and renders imperfect the chymification of that which would otherwise have been completed. Hence the sense of weight and disagreeable fulness, attendant on an unusually hearty meal ; the subsequent derange- ment of the digestive functions, and consequent acidities and vitiated contents of the primae vise, from acetic fer- mentation in the stomach, and imperfect formation of chyle in the intestines.
clearly demonstrated^ a very important step would be gained in the science of Dietetics. It would not only afford the strongest bar- rier against one of the prevailing sins of the age — eating too much — but would be of incalculable service in the preservation and cure of indigestion, and its gloomy train of consequences. — Editor.
( 58 )
CHAPTER V.
MASTICATION, INS ALIVATION, AND DEGLUTITION.
Uses of mastication — Nature and use of saliva — Saliva not essen- tial to digestion — Mastication essential as a means of dividing food into minute portions — Deglutition ought to be slow, as the stomach admits only of slow distention.
These are the preliminary steps in the process of di- gestion. The comparative importance of these processes has been elevated or depressed, according to the prepon- derance which each of them may have received from the opinions of the different physiologists who have made them subjects of observation. As man and animals are constituted, they are all absolutely necessary to the diges- tion of food. But in an abstract point of view, discon- nected as a means of introducing ingestae into the sto- mach, I believe I hazard nothing in saying that they may be considered as perfectly non-essential to chymification. If the materia alimentaria could be introduced into the stomach in a finely divided state, the operations of mas- tication, insalivation and deglutition, would not be ne- cessary. Aliment is as well digested and assimilated, and allays the sensation of hunger as perfectly, when in- troduced directly into the stomach, in a proper state of division, as when the previous steps have been taken, as may be seen by some of the following experiments. If
USES OF SALIVA. 59
particular importance is to be attributed to any of these previous steps, it is certainly due to mastication ; though an undue importance has of late been given to the ac- tion of the saliva. Professor Jackson, of Philadelphia, who has lately published a physiological work on the " Structure and Functions of the Animal Organism," has elevated saliva to a rank in the process of digestion, sel- dom before claimed for it. He considers it the principal solvent, or macerating agent, of alimentary matter. He is sustained in this opinion by Montegre and others. Even Magendie is inclined to favour this belief
It is remarked by Paris (On Diet, p. 37), that the in- troduction of saliva into the stomach is " obviously essen- tial to a healthy digestion." That it is generally intro- duced into the stomach with the food is very obvious ; the nature of its action is not so clear. In most of the experiments that follow, artificial digestion was performed without the admixture of saliva. Chyme formed in this way, exhibited the same sensible appearances, and was affected by reagents in the same way, as that which was formed from food which had been previously mas- ticated, mixed with the saliva, and swallowed. It would seem, from two or three of the experiments on artificial digestion, which were instituted for the purpose of com- parison, that the mixture of saliva with the gastric juice rather retarded its solvent action. But I do not wish to deny the utility of the saliva. It is certainly import- ant as a preliminary to digestion. Its legitimate and only use, in my opinion, is to lubricate the food, and to facilitate the passage of the bolus through the or-
60 SALIVA NOT ESSENTIAL TO DIGESTION.
gans of deglutition. In this point of view, it is essential. Dry food cannot be swallowed until it receives an admix- ture of a fluid, whether it be saliva or some other liquid, is not, I conceive, a matter of much importance. Any one, disposed to try the experiment, may satisfy himself of this fact, by attempting to swallow a mouthful of dry cracker, meal, or magnesia. He will find it impossible to make the organs of deglutition act till a quantity of fluid is mixed with it. Water will answer the purpose nearly as well as saliva, though the mucous properties of this secre- tion may give it a slight preference.
Pathology is not, in my opinion, much indebted to Ruysch, who attributed the loss of appetite to the waste of saliva in a person who was afflicted with a fistula in one of the salivary ducts ; nor to the opinion advanced by others, that the constant spitting of maniacal patients, in- duces loss of appetite. The truth is, that in both cases, the effects are attributed to the wrong causes. There is no difficulty in believing that a foul ulcer in the mouth would be liable to produce nausea and want of appetite ; nor that maniacal patients are generally, if not always, af- fected with diseased organs of digestion. I have known many persons to spit freely and constantly, whose appe- tites and digestion were perfect. Those who smoke to- bacco are constantly discharging large quantities of saliva; and yet I am not aware that dyspepsia is more common with them than with others.
I entirely dissent firom the opinion advanced by the author above referred to (Paris), that " insahvation is as essential as mastication." The use of mastication is to
MASTICATION ESSENTIAL TO DIGESTION* 61
separate the food into small particles, so that the solvent of the stomach may be applied to a greater extent of surface. There is no mystery about this. Every body knows that the smaller the particles of matter that are submitted to the action of a chemical agent, the more vigorously the agent will act upon them, and the sooner they will be dissolved or decomposed.* Mastication is absolutely necessary to healthy digestion. If aliment, in large masses, be introduced into the stomach, though the gastric juice may act upon its surface, chymifi cation will proceed so slowly, that other changes will be likely to commence in its substance before it will become com- pletely dissolved. Besides, the stomach will not retain undigested masses for a long time, without suffering great disturbance. It is governed by certain laws with respect to aliment. After food has been retained for a certain length of time undigested, say from five to ten hours, according to the healthy or diseased state of that organ, or the quantity received into it, it is either rejected by vomiting, or is permitted to pass into the duodenum and lower bowels, where its presence almost invariably pro- duces colic, flatulence, &c. When, however, the sto- mach is unusually debilitated, food is frequently retained for twenty- four hours or more, and is sometimes the cause of most distressing symptoms, producing, particu- larly in children, convulsions and death. I therefore
* In using the word solvent or solution^ in reference to the gas trie juice, I wish to be understood to mean a chemical action, ana- logous to that of the action of mineral acids on the metals ; not like the solution of sugar or salt in water.
62 DEGLUTITION OUGHT TO BE GRADUAL.
consider mastication as one of the most important pre- liminary steps in the process of digestion.
With respect to deglutition, I shall make but a few remarks. It is important for the preservation of health, that this process should be effected slowly. If food be swallowed rapidly, more will be generally taken into the stomach before the sensation of hunger is allayed, than can be digested with ease. If due attention be paid to the previous step of thorough mastication, we shall not be so likely to err in this latter one.
Swallowing very rapidly, produces irregular contrac- tions of the muscular fibres of the oesophagus and stomach ; disturbs the vermicular motions of the rugae ; and inter- rupts the uniform action of the gastric apparatus.
The stomach is not designed to receive more food than can be duly mixed with the gastric solvent, already in its proper vessels, or in a state of preparation in the bloodvessels. Perfect harmony of action must exist throughout the whole apparatus, or derangement of healthy action will ensue.
The stomach will not admit of the introduction of food, even of a liquid kind, through the aperture, at a rapid rate. If a few spoonfuls of soup, or other liquid diet, be put in with a spoon or funnel, the rugae gently close upon it, and gradually diffuse it through the gastric cavity, entirely excluding more during this action. When a relaxation takes place, another quantity will be received in the same manner.
If the valvular portion of the stomach be depressed, and solid food be introduced, either in entire pieces or
NOTE BY THE EDITOR. 63
finely divided quantities, the same gentle contraction, or grasping motion, takes place, and continues for fifty or eighty seconds ; and will not allow of the introduction of another quantity until the above time has elapsed ; when the valve may again be depressed, and more food be put in. Food and drinks will be received through the aper- ture no faster, even when the stomach is entirely empty, than they are ordinarily received through the oesophagus. When the subject of these experiments is so placed that the cardia can be seen, and he is allowed to swallow a mouthful of food, the same contraction of the stomach, and closing upon the bolus, is invariably observed to take place at the oesophageal ring.
Note hy the Editor.
This gradual admission of food into the stomach, seems to be in relation with the gradual supply of gastric juice, necessary for the solution of each portion, and it explains why at a social dinner, where we eat slowly and with short intervals of conversation, we are able to consume a larger quantity and digest it more easily, than when we sit down alone and eat hurriedly and without interruption. In the one case, the stomach has time to adapt its capacity and its gastric secretion to the quantity taken in ; while in the other, it can do neither.
( 64 )
CHAPTER VI.
OF DIGESTION BY THE GASTRIC JUICE*
Chymification— Agents of. — Spallanzani's theory of Digestion—* Common opinions regarding the gastric juice — Gastric juice has a solvent power — Analysis of— Composition of— -Its^action is purely chemical — Gastric juice described-— Its quantity pro- portioned to wants of the system — Its secretion and action begin on the contact of food-^Evils of frequent eating ex* plained — Gastric juice supplied to all the food at once when the latter is not in excess — Old and new food mix — Effects of exercise on digestion — Bile not essential to chymification— Chyme, its nature and progress — Montegre's theory of diges-. tion — Smith's and Jackson's theories—General remarks.
Chymification is effected in the stomach. It is the first stage, proper, of the conversion of aUment into blood ; though in the ordinary course of proceeding, af^ animals are constituted, some previous steps are neces- sary. After the aliment has been received into the stomach, it is subjected to certain evolutions, or motions, propagated by the muscular fibres of that organ ; and is acted upon through the agency of some principle, wliich changes it from a heterogeneous mixture of the various kinds of diet, submitted to its action, to an uniform ho- mogeneous semi-fluid, possessing properties distinct from the elements of which it is composed. The length of time consumed in the operation is various. It depends upon the quantity or quality of the ingestse, the healthy
AGENTS OF CHYMIFICATION. 65
or diseased state of the stomach, &c. In the various ex- periments which I have made, the medium time may be calculated at about three and a half hours.
It has been suggested by many physiologists, and posi- tively asserted by some, that there is considerable in- crease of the temperature of the stomach during the di- gestion of a meal. But from the result of a great num- ber of experiments and examinations, made with a view of ascertaining the truth of this opinion, in the empty and full state of the organ, and during different stages of chymification, I am convinced that there is no alteration of temperature, unless some other circumstance should produce it. Active exercise always elevates the tempe- rature of the stomach, whether fasting or full, about one and a half degrees.
With respect to the agent of chymification, that prin- ciple of life which converts the crude aliment into chyme, and renders it fit for the action of the hepatic and pan- creatic fluids, and final assimilation and conversion into the fluids, and the various tissues of the animal organism — no part of physiology has, perhaps, so much engaged the attention of mankind, and exercised the ingenuity of physiologists. It has been a fruitful source of theoreti- cal speculation, from the Father of Medicine down to the present age. It would be a waste of time to attempt to refute the doctrines of the older writers on this sub- ject. Suffice it to say, that the theories of Concoction, Putrefaction, Trituration, Fermentation, and Macera- tion, have been prostrated in the dust before the lights of science, and the deductions of experiment. It was
F
66 SPALLANZANl's THEORY OF CHYMIFICATION.
reserved for Spallanzani to overthrow all these unfound- ed hypotheses, and to erect upon their ruins, a theory which will stand the test of scientific examination and experiment. He established a theory of chemical so- lution, and taught that chymification was owing to the solvent action of a fluid, secreted by the stomach, and operating as a true menstruum of alimentary substances. To this fluid he gave the name of Gastric Juice. It does not come within the scope of this work to give a detail of the experiments and reasoning which wrought conviction in the mind of this great man. It is only ne- cessary to say, that it was the result of patient and per- severing experiment and research.
The truth of Spallanzani's theory has been sustained, so far as relates to the most important part, the existence of a chemical solvent, by all who have made fair exami- nations and experiments on the subject. The experi- ments of Tiedemann and Gmelin, of Leuret and Las- saigne, confirm the same theory.
By far the most respectable and intelligent physiolo- gists have now settled down in the belief that chymifica- tion is effected in the stomach, by a peculiar and specific solvent, secreted in that organ, called, after Spallanzani, the Gastric Juice. From the difficulty, however, of ob- taining and submitting such fluid to the test of experi- ment, and the diversity of results in the examination of such as has been obtained, much indefiniteness is expe- rienced on this subject. The presence of an active sol- vent is rather an admission on their part — a conclusion from the effect to the cause. Broussais, speaking on this
OPINIONS ON THE GASTRIC JUICE. 67
subject, says : " It remains for us to know whether the portion of mucous membrane, belonging to the stomach, contains secretory organs, the office of which is to furnish a fluid, fit to produce the assimilation of nutritive sub- stances/' And again, speaking of the gastric juice, " The question is as yet undecided, though, if we are to judge by analogy, we shall observe that many animals are furnished with gastric glands, supplying a digestive liquid." This author admits the presence of a solvent fluid in the stomach, without, however, attempting to ex- plain its specific effects, or mode of operation ; for he says, in another place, " We have expressed our opinion on this subject ; but whether the gastric fluids possess an assimilating property, which, for ourselves, we admit, without pretending to demonstrate its actual presence," &c.
Richerand, Bostock, and nearly all the authors of mo- dern date, teach the doctrine of digestion by the gastric juiee, without, however, pretending to explain its exact mode of operation. Professor Dunglison, whose work on " Human Physiology," taken as a whole, is perhaps the most comprehensive, arrives at the same conclusion. He says, " We have too many evidences in favour of the che- mical action of some secretion fi-om the stomach during digestion, to permit us to doubt for a moment of the fact." And again, " From all these facts, then, we are justified in concluding, that the food in the stomach is subjected o the action of a secretion which alters its properties, and is the principal agent of converting it into chyme."
I have referred to these learned authors, with the view
68 GASTRIC JUICE HAS A SOLVENT POWER.
of shewing the exact state of the science on this sub- ject.
Though the theory of chymification by the gastric juice has become almost universal with physiologists, and the medical profession in general, still there are some, even of very modern date, who, with all the lights of science and experiment, from aversion to the slow and tedious processes by which truths are attained, or, per- haps, from the ambition of becoming the discoverers of some new and extraordinary process, or the projectors of some fanciful theory, deny the power of the gastric juice, or even the existence of such a fluid ; and set at naught the experiments, observations, and opinions of the ablest phy- siologists and most experienced writers on this subject.
That chymification is effected by the solvent action of the gastric juice, aided by the Tnotions of the stomachy and the natural warmth of the system, not a doubt can remain in die mind of any candid person, who has had an opportunity to observe its effects on alimentary substances, or who has the liberality to credit the opinions of those who have had such opportunities.
It has been objected to this hypothesis, that the sensible properties of the gastric juice contradict the opinion of its active solveiit effect. But we should recollect that many things which make very little impression on our external senses, produce most astonishing effects in other situations. The air which we breathe, by which we are surrounded, and which, to our external senses, is almost inappreciable, is one of the most powerful and destructive agents in nature — one portion of which is capable of com-
ANALYSIS OF GASTRIC JUICE. 69
bining with all grades of matter, either slowly and imper- ceptibly, as in the gradual decay of all substances, or ra- pidly, as in the combustion of wood, or even the hardest metals, — and which, by means inexplicable to us, sus- tains in life and being the whole of animated nature.
The gastric juice has been submitted to chemical ex- amination and analysis, with various results. Perhaps in the present state of the science of chemistry it will not be practicable to ascertain its exact chemical character. The parcels heretofore submitted to analysis have been very impure ; but the result of even these partial exami- nations has been, to shew that this fluid contains a por- tion of free muriatic acid, combined with the acetic and some salts. In the winter of 1832-33, I submitted a quantity of gastric juice, with no other admixture except a small proportion of the mucus of the stomach, to Pro- fessor Dunglison for examination, who, with the assist- ance of the professor of chemistry of the Virginia Uni- versity, effected the following analysis, and was kind enough to communicate the result to me by letter.
" University of Virginia, " My Dear Sir, Feb. 6. 1833.
" Since I last wrote you, my friend and colleague Pro- fessor Emmett, and myself, have examined the bottle of gastric fluid which I brought with me from Washington, and we have found it to contain free muriatic and acetic acid, phosphates and muriates, with bases ofpotassa, soda, magnesia, and lime, and an animal matter soluble in cold icater, but insoluble in hot. We were satisfied, you recollect, in Washington, that free muriatic acid was pre-
70 ANALYSIS OF GASTRIC JUICE.
sent, but I had no conception it existed to the amount met with in our experiments here. We distilled the gas- tric fluid, when the free acid passed over ; the salts and animal matter remaining in the retort. The quantity of chloride of silver thrown down on the addition of the ni- trate of silver, was astonishing."
I had been long convinced of the existence of free mu- riatic acid in the gastric fluids. Indeed, it is quite obvi- ous to the sense of taste ; and most chemists agree in this, however they may be at variance with respect to the other constituents. The analysis of Professors Dungli- son and Emmett is certainly as satisfactory as any that has as yet been made. It is a question, too, whether gas- tric juice, in so great a state of purity, has ever before been subjected to chemical analysis.
It is to be hoped that no one will be so disingenuous as to attribute to Professor Dunglison the design of find- ing the existence of certain chemical agents in the gas- tric juice, with the view of propping the theory of the chemical action of this fluid, which he has maintained in his work on " Human Physiology ;'' or, in other words, to say that he had determined to find certain results ; and that he had accordingly found them. Those who are ac- quainted with him know that his candour and fairness are above the reach of suspicion, and that he would be equally willing to retract a false opinion as to maintain a correct one. Another quantity was sent to him for further analysis, but I regret that no report has yet been received from him.
In April of the present year (1833) a parcel was sub-
ANALYSIS OF GASTRIC JUICE. 71
mitted to Benjamin Silliman, M.D., Professor of Chemis- try in Yale College. Professional engagements prevent- ed his examination of the fluid until the 2d of August, when he sent me the following result : —
" Examination of the Gastric Fluid, Aug. 2, 1833.
"1. The fluid, after being kept in a closely-corked phial more than three months, from April to August, and most of the time in a cellar, remained unaltered, except the formation of a pellicle upon the surface, slightly dis- coloured by red spots. A second pellicle appeared after the precipitation of the first. It was thicker, and more discoloured with dark red spots, like venous blood.
" 2. The fluid was cloudy, like a solution of gum ara- ble ; but on filtering it became perfectly clear, and of a slight straw-yellow tinge.
" 3. The pellicles, which had the appearance of in- spissated mucus, after being separated from the fluid, be- came, after exposure to the air, throughout of a brownish- red colour, resembling the inner portion of a mass of co- agulated blood. This change seemed to result from a sudden oxygenation.
" 4. The fluid exhaled a slight odour^ — not disagree- able— rather aromatic, and very similar to that which it at first exhaled, but not so strong. It was then rather disagreeable.
" 5. Taste feebly saline, not disagreeable.
" 6. Test papers of litmus, alkanet, and purple cab- bage, were decidedly reddened. Turmeric paper under- went no change ; but, when previously browned by an
72 COMPOSITION OF GASTRIC JUICE.
alkali (ammonia), the gastric fluid restored the yellow co- lour.
" ?• Nitrate of silver gave a dense white precipitate, which, after standing five minutes in the sun's light, turn- ed to a dark brownish- black, thus indicating muriatic acid. Mur. and nit. barytes gave a slight opalescence, indicat- ing a trace of sulphuric acid ; not improbably there was also some phosphoric acid.
" 8. Specific gravity, when taken in a small thin glass tube, containing 201 grs. of distilled water, when filled with the gastric fluid its weight was increased 1 gr. ; weight of the gastric liquor, therefore, 202 grs. The specific gravity is, therefore, about 1.005. But little solid matter in solution."
At the instance of Professor Silliman, I committed to the care of Mr Ghan, Consul of his Swedish Majesty in New York, a bottle containing one pint of gastric juice, to be transmitted by him to Professor Berzelius of Stock- holm, one of the most eminent chemists of the age, with a request that he would favour me with an analysis. Some unavoidable delay was experienced in forwarding the bot- tle, and no returns have yet been received. It is hoped, however, that they will arrive in time to be attached in an appendix to this volume.
The following results have been obtained from partial examinations and analyses of the gastric juice, or rather, in most instances, of the mixed fluids of the stomach.
Spallanzani, in 1793, after many experiments, declared the gastric juice to be entirely neutral, a solvent for all-
COMPOSITION OF GASTRIC JUICE. 73
mentary matter within and without the stomach, that it did not -putrefy at the ordinary temperatm'e of the sto- mach, but preserved animal matters from putrefaction, and dissolved them with the aid of heat.
Scopoli found in the gastric juice of the rook, water, gelatine, a saponaceous matter, muriate of ammonia, and phosphate of lime.
Carminiti, in 1795, found it, in carnivorous animals, salt and bitter, and frequently acid when they had eaten, but not so when fasting.*
Viridet, Werner, Hunter, and others, found the gas- tric juice acid.
MM. Marquart and Vauquelin found albumen and free phosphoric acid in it.
Tiedemann and Gmelin found it to contain, on analysis, muriatic and acetic acid, mucus, very little or no albumen, salivary matter, osmazome,'muriate and sulphate of soda. In the ashes, carbonate, phosphate, and sulphate of lime, and chloride of calcium. Principally from carnivorous animals.
Lcuret and Lassaigne, in a hundred parts, found wa- ter ninety-eight, lactic acid, muriate of ammonia, muriate of soda, animal matter soluble in water, mucus, and phos- phate of lime two parts.
Montegre (1812), who could vomit at will^\ and who analyzed the fluid so obtained, declared it not to be acid —
* Probably because the fluid found in the stomach when fasting was not gastric juice.
t See remarks near the close of this section on Montegre's experiments.
G
74 GASTRIC JUICE HAS ACTIVE PROPERTIES.
not a solvent — not slow to putrefy — and so much like sa^ liva, that he regards it as saliva swallowed.
Prout, 1824, declares the gastric juice to be really acid — does not contain an organic acid, but free hydrocliloric or muriatic acid.
These opinions are certainly discordant. The majority of evidence, however, is in favour of the existence of pretty active chemical agents in the gastric fluids — per- liaps not sufficient, in comparison with the ordinary ope- rations of chemistry, to account for the digestion or solu- tion of aliment.
The discrepance of results in the reports of those who have had opportunities of examining the process of, and have made experiments on, artificial digestion, by the gastric juice, as well as in the chemical examination of this fluid, has been owing more to the difficulty of obtain- ing it pure, in sufficient quantity, and under proper circum- stances, than to any real difference in its effects. Under the circumstances in which the following experiments were made, I flatter myself that these difficulties have been obviated ; and if the inferences are incorrect, the blame must be attached to the experimenter. He can only say, that the experiments were made in good faith, and with a view to elicit facts.
I think I am warranted, from the result of all the ex- periments, in saying, that the gastric juice, so far from being " inert as water," as some authors assert, is the most general solvent in nature of alimentary matter — even the hardest bone cannot withstand its action. It is
GASTRIC JUICE HAS ACTIVE PROPERTIES. 75
capable, etien out of the stomachy of effecting perfect di- gestion, with the aid of due and uniform degrees of heat (100°. Fahrenheit), and gentle agitation, as will be seen in the following experiments.
The fact that alimentary matter is transformed^ in the stomach, into chyme, is now pretty generally conceded. The peculiar process by which the change is effected, has been, by many, considered a problem in physiology. Without pretending to explain the exact inodits operandi, of the gastric fluid, yet I am impelled by the weight of evidence, afforded by the experiments, deductions, and opinions of the ablest physiologists, but more by direct experiment, to conclude that the change eflPected by it on aliment is purely chemical. We must, I think, regard this fluid as a chemical agent, and its operation as a che- mical action. It is certainly every way analogous to it ; and I can see no more objection to accounting for the change effected on the food, on the supposition of a che- mical process, than I do in accounting for the various and diversified modifications of matter, which are operated on in the same way. The decay of the dead body is a che- mical operation, separating it into its elementary prin- (tiples — and why not the solution of aliment in the sto- mach, and its ultimate assimilation into fibrine, gelatine, and albumen ? Matter, in a natural sense, is indestruc- tible. It may be differently combined ; and these com- binations are chemical changes. It is well known that all organic bodies are composed of very few simple prin- ciples, or substances, modified by excess or diminution of some of their constituents.
76 GASTRIC JUICE ACTS CHEMICALLY*
The gastric juice appears to be secreted from number- less vessels, distinct and separate from the mucous folli- cles. These vessels, when examined with a microscope, appear in the shape of small lucid points, or very fine papillae, situated in the interstices of the follicles. They discharge their fluid only when solicited to do so, by the presence of aliment, or by mechanical irritation.
Pure gastric juice, when taken directly out of the sto- mach of a healthy adult, unmixed with any other fluid, save a portion of the mucus of the stomach, with which it is most commonly, and perhaps always combined, is a clear transparent fluid ; inodorous, a little saltish, and very perceptibly acid. Its taste, when applied to the tongue, is similar to thin mucilaginous water, slightly aci- dulated with muriatic acid. It is readily diffusible in water, wine, or spirits ; slightly effervesces with alkalis ; and is an effectual solvent of the materia alimentaria. It possesses the property of coagulating albumen in an emi- nent degree ; is powerfully antiseptic, checking the putrefaction of meat ; and effectually restorative of healthy action, when applied to old foetid sores, and foul ulcera- ting surfaces.
Saliva and mucus are sometimes abundantly mixed w^ith the gastric juice. The mucus may be separated, by filtering the mixture through fine linen or muslin- cambric. The gastric juice, and part of the saliva, will pass through, while the mucus and spumous, or frothy part of the saliva, remains on the filter. When not se- parated by the filter, the mucus gives a ropiness to the. fluid, that does not belong to the gastric juice, and soon
APPEARANCE OF GASTRIC JUICE. 77
falls to the bottom, in loose white flocculi. Saliva im- parts to the gastric juice an azure tinge, and frothy ap- pearance ; and, when in large proportion, renders it foetid in a few days ; whereas the pure gastric juice will keep for many months, without becoming foetid.
The gastric juice does not begin to accumulate in the ca- vity of the stomach, until alimentary matter be received, and excite its vessels to discharge their contents, for the imme- diate purpose of digestion. It is then seen to exude from its proper vessels, and increases in proportion to the quan- tity of aliment naturally required, and received. A de- finite proportion of aliment, only, can be perfectly digested in a given quantity of the fluid. From experiments on artificial digestion, it appears that the proportion of juice to the ingestae, is greater than is generally supposed. Its action on food is indicative of its chemical character. Like other chemical agents, it decomposes or dissolves, and after combining with a fixed and definite quantity of matter, its action ceases. When the juice becomes sa- turatedy it refuses to dissolve more ; and, if an excess of food have been taken, the residue remains in the stomach, or passes into the bowels in a crude state, and frequently becomes a source of nervous irritation, pain, and disease, for a long time ; or until the vis medicatrix natures, re- stores the vessels of this viscus to their natural and healthy actions — either with or without the aid of medi- cine J^
Such are the appearance and properties of the gastric
* This important principle ought never to be lost sight of by the practitioner.— Editor.
78 GASTRIC SECRETION PROPORTIONED TO WANTS.
juice ; though it is not always to be obtained pure. It varies with the changing condition of the stomach. These variations, however, depend upon the admixture of other fluids, such as saUva, water, mucus, and some- times bile ; and, perhaps, pancreatic juice. The special solvent itself — the gastric juice — is, probably, invariably the same substance. Derangement of the digestive or- gans, slight febrile excitement^ fright^ or any sudden af- fection of the passions,) causes material alterations in its appearance. Overburthening the stomach, produces aci- dity a,nd rancidity in this organ, and retards the solvent action of the gastric juice. General febrile irritation seems entirely to suspend its secretion into the gastric cavity ; and renders the villous coat dry, red, and irri- table. Under such circumstances, it will not respond to the call of alimentary stimulus.* Fear and anger check its secretion, also ; — the latter causes an influx of bile into the stomach, which impairs its solvent properties.
When food is received into the stomach, the gastric vessels are excited by its stimulus to discharge their con- tents, and then chymification commences. It has been a favourite opinion of authors, that food, after it has been received into the stomach, should " remain there a short period before it undergoes any change ;"t the com- mon estimate is one hour. But this is an erroneous conclusion, arising from inaccuracy of observation. Why should it remain there unchanged ? It has been received
* Hence the obvious necessity of a scrupulous attention to diet during fever, and other acute diseases. — Editor,
-|- Paris on Diet, p. 39.
ITS ACTION ON FOOD IS IMMEDIATE. 79
into the organ which is to effect an important change upon it — the gastric juice is ready to commence its work of solution soon after the first mouthful is swallowed ; and, certainly, if we admit that the gastric juice performs the office of a chemical agent, which most physiologists allow, it is contrary to all our notions of chemical action, to allow it one moment to rest. It must commence its operation immediately. That [it does so, is distinctly manifested by close observation of its action on food, in the healthy stomach.
But Paris is not alone in this opinion. It appears to have been a favourite doctrine ; and has been regularly handed down from one physiologist to another as a sort of heir'loom to the profession. The successors in the physiological sciences seem to have been compelled to receive it with the legacy of their predecessors, without any doubt of its legitimacy ; when, with a little rational examination of the subject, it would have been found a fair subject of rejection. It will be seen, by the follow- ing experiments, that it has not the slightest foundation in truth ; and to them I refer the reader.
It has been said that when one meal follows another in quick succession — or, in other words, when a subsequent meal is taken before the previous one is digested, that it somehow disturbs the process of digestion. This is ge- nerally true ; and it allows of a definite solution. It is because more is received into the storiiach, in the aggre- gate, than the gastric juice can dissolve. And this dis- turbance will result as well when too much food has been taken at once, as when too much has been received in
80 EVILS OF FREQUENT EATING EXPLAINED.
rapid succession. But, if the quantity be moderate, no ill effect will ensue. Many children are in the habit of eat- ing as often as once an hour through the day, in small quantities, without experiencing any bad consequences. Cooks are also accustomed to the p^ractice of constantly tasting of the various articles of food which they are pre- paring for the table, and yet I am not aware that they suffer any inconvenience from the habit. From these and other facts, as well as from direct experiment, I think it is perfectly apparent that digestion must progress as well before as after the expiration of an hour. If, as has been suggested, the ingestion of food, in addition to the delay to itself, retards or stops the chymification of that which had been previously received, aliment, as it relates to those children who eat hourly, would be constantly ac- cumulating, and there would remain in the stomach at night the whole quantity taken through the day — a sup- position not to be credited, even by those disposed to make the most of a favourite opinion or doctrine.
Doctor Wilson Philip, in his " Treatise on Indiges- tion," says, " the layer of food lying next to the surface of the stomach is first digested, and, in proportion as this undergoes the proper change, and is moved by the mus- cular action of the stomach, that next in turn succeeds, to undergo the same change." That chymification^com- mences on the surface of the food, I have no doubt ; but I apprehend this to be the case as it respects each indi- vidual portion^ and not the whole mass. I have frequent- ly taken out portions from the stomach a few minutes after they had been received into that organ, when they
EVILS OF FREQUENT EATING EXPLAINED. 81
appeared to have received a full supply of gastric juice for perfect digestion, when submitted to the artificial mode. When a due and moderate supply of food has been received, it is probable that the whole quantity of gastric juice for its complete solution is secreted, and mixed with it in a short time. When an unusually full meal has been eaten, the necessary quantity for its com- plete solution is not so readily supplied. If a tenacious mass of food be used, the external portion of the whole quantity is first acted on, digested, and succeeding por- tions presented, &c. There is no ground for the opinion inferred, that the gastric juice never leaves the parietes of the stomach, except as it chymifies food. It is a thin fluid, and is governed by the same laws that other thin fluids are. From numerous examinations of the stomach, I feel warranted in saying, at least in the human subject, that there is a perfect admixture of gastric juice and food — that the particles of food are constantly changing their relations with each other, and that they are mixed with a quantity of fluid, the gastric juice, liquids that have been taken during the meal, and (as there has generally been observed a large proportion of fluid, even after a dry and solid meal) I have been led to suspect a synthe- tic formation of water from its elements. This mixture is perfectly heterogeneous at first, and is kept in constant agitation by the churning motions of the stomach. If the contents of the stomach be taken out in from thirty minutes to an hour after eating, they will be found to be composed of perfectly formed chyme and particles of food, intimately mixed and blended ; sometimes in larger and
82 GASTRIC JUICE APPLIED TO ALL THE FOOD AT ONCE.
sometimes in smaller proportions, according to the vigor- ous or enfeebled state of the digestive organs, or the quantity or quality of aliment taken. Most commonly, if the meal have been moderate, the process of digestion will continue in the portion taken out, when it is placed on the bath at a proper temperature, and the motions of the stomach are imitated.
From the circumstance, that the introduction of sponge, tubes, pebbles, &c., by Spallanzani and others excited the discharge of the gastric juice, and from the fact that the gum-elastic tube, in my experiments, produced the same effect when the stomach was empty and healthy, I infer that the first effect of aliment on the stomach is one of irritation of the gastric papillae, thus exciting the dis- charge of the gastric juice, and stimulating the muscular fibres of the stomach. The vermicular motions, being excited by mechanical irritation, not only carry the in- gestae into all parts of the stomach, and diffuse its me- chanical influence throughout the whole inner surface of this organ ; but, by this means, they uniformly mix the aliment with the gastric juice, which is constantly being secreted in proportion to the quantity of food received into the stomach (unless that be too much for the wants of the economy) until chymification be completed. Some stimulus seems to be necessary to continue the motions of the stomach after chymification is accomplished, in order to effect its complete discharge into the lower bowels. And it appears highly probable that the com- pound fluid of gastric juice and aliment, or chyme, by its acquired acid properties, affords this stimulus, and pro-
OLD AND NEW FOOD MIX. 83
pagates the contractile motions of this organ, even after the mechanical irritation of the crude food ceases. This fluid acquires new chemical properties, becomes more acid and stimulating, as chymification advances, until it is completed. When it is all transferred to the duodenum, the motions of the stomach cease.
From a number of experiments on rabbits by Doctor Wilson Philip* with the view of ascertaining the process of digestion, this gentleman has brought his mind to the conclusion, that when food has been taken at diiferent times, " the new is never mixed with the old food." With every feeling of respect for so valuable and indefatigable a contributor to physiological science, I must beg leave, however, to dissent from this opinion. In many of his experiments the rabbits were killed soon after the intro- duction of a fresh quantity of food, and, generally, of a very different kind. The result was, that it was found separate from the old food, which was in an advanced stage of digestion. It was in the centre of the old food, and surrounded by it. This is precisely where a new bolus would be received, and retain its shape and con- sistence, in some measure, until disturbed and broken up by the motions of the stomach. By allowing sufficient time for the action of this organ, it is probable that the line of separation would not have been perceived. In- deed, the Doctor concedes that, when the second quan- tity of food was of the same kind as the first, and the rab- bit had been left to live for some time, the line of sepa- ration was very indistinct. It appears that he fed rab- * On Digestion.
84 NEW AND OLD FOODS MIX.
bits on oats^ and, after making them fast for sixteen or seventeen hours, he fed them on as much cabbage as they chose to eat, " and killed them at different periods, from one to eight hours after they had eaten it ;" when the line of separation between the new food and that which had been eaten from eighteen to twenty-Jive hours before was no doubt quite distinct. I confess I know very little about the habits of these animals as it respects their modes of digestion ; but I should be inclined to think that, if the " line of separation" between the two portions of food were not sufficiently distinct, it was not for want oitime. In man, one-fifth of the time would have been more than sufficient to have disposed of any reasonable quantity of food.
Comparative physiology, as well as comparative ana- tomy, is undoubtedly very useful ; but, at the same time, it will not do to make it of general application. The rab- bit is a ruminating animal ; and is it not probable that the " new food" found in the " small curvature," if it be in fact retained there, is detained for the purpose of re- gurgitation and remastication before it is digested ? If the circumstance be true, and there be no deception in the case, I think this snust be the design of the con- trivance.
Arguments from analogy may be very plausible, and are certainly very allowable when the subject presents no other mode, but they are not conclusive. We cannot judge of the mode of digestion in the human stomach by that of animals, particularly the granivorous and rumina- ting animals. Carnivorous animals most resemble man
EFFECT OF EXERCISE ON DIGESTION. 85
in their digestive apparatus. One thing is certain, and it is capable of demonstration in the stomach of the sub- ject of these experiments, that old and new food, if they are in the same state of comminution, are readily and speedily mixed in the stomach.
On the subject of exercise or repose, during the diges- tion of a meal, there has been some diversity of opinion. It has generally been conceded, however, that a state of repose is most favourable to chymification. It has been said that during the digestion of aliment, the energies of the system were centred on the stomach, and should not be withdrawn to any distant part ; that the stomach be- comes a " centre of fluxion," &c. &c. I protest, again, against the use of terms which have no definite meaning. I believe the benefits of science will be better subserved by adhering to facts, and the deductions of experiment, than by the propagation of hypotheses founded on un- certain data. From numerous trials, 1 am persuaded that moderate exercise conduces considerably to healthy and rapid digestion.* The discovery was the result of accident, and contrary to preconceived opinions. I ac- count for it in the following way. Gentle exercise in-
* Perhaps the Author's proposition is expressed in too general terms. After a moderate meal, such as we are accustomed to take at luncheon, moderate exercise seems to promote digestion. But that active exercise immediately after z.full meal, such as is gene- rally taken for dinner, is prejudicial to its digestion, seems to me to be proved by daily and unequivocal experience, and I have often seen patients labouring under indigestion benefited by refraining from it. During the later stages of digestion, how- ever, beginning an hour or two after eating, moderate exercise is unquestionably conducive to its completion. — Editor.
86 EFFECTS OF EXERCISE ON DIGESTION.
creases the circulation of the system, and the temperature of the stomach. This increase of temperature is gene- rally about one and a half degrees. Now, if the gastric juice be a solvent, its action is similar to other chemical solvents, and its rapidity is increased in proportion to the elevation of temperature. Of the reason, I leave others to judge ; the effect is certain. Severe and fatiguing exercise, on the contrary, retards digestion. Two rea- sons present themselves for this, — the debility which fol- lows hard labour, of which the stomach partakes ; and the depressed temperature of the system, conseauent upon perspiration and evaporation from the surface.
Exercise, sufficient to produce moderate perspiration, increases the secretions from the gastric cavity, and pro- duces an accumulation of a limpid fluid within the sto- mach, slightly acid, and possessing the solvent properties of the gastric juice in an inferior degree. This is pro- bably a mixed fluid, a small proportion of which is gastric juice.*
Bile is not essential to chymification. It is seldom found in the stomach except under peculiar circum- stances. I have observed that when the use of fat or oily food has been persevered in for some time, tliere is generally the presence of bile in the gastric fluids.
* I have often witnessed the effect of exercise attended with moderate perspiration in improving both the appetite and diges- tion, and am therefore in the habit of'recommending it to be car- ried to that extent by dyspeptic patients. In relieving the ten- dency to acidity, its good effects are equally apparent. The observations in the text afford a good physiological explanation of the fact, — Editor.
BILE NOT ESSENTIAL TO CHYMIFICATION. 87
Whether this be a pathological phenomenon, induced by the peculiarly indigestible nature of oily food, or whether it be a provision of nature to assist the chymification of this particular kind of diet, I have not as yet satisfied myself. Oil is affected by the gastric juice with consi- derable difficulty. The alkaline properties of the bile may render it more susceptible of solution in this fluid, by altering its chemical character. Irritation of the py- loric extremity of the stomach with the end of the elastic tube, or the bulb of the thermometer, generally occasions a flow of bile into this organ. External agitation, by kneading with the hand on the right side, over the re- gions of the liver and pylorus, produces the same effect. It may be laid down as a general rule, however, subject to the exceptions above mentioned, that bile is not ne- cessary to the chymification of food in the stomach. Magendie «ays, " I believe that, in certain morbid con- ditions, the bile is not introduced into this organ " (the stomach) ; inferring, that in a healthy state it is always to be found there. There can hardly be a greater mis- take. With the exceptions that I have mentioned, it is never found in the gastric cavity in a state of health ; and it is only in " certain morbid conditions" that it is found there.*
* There is one form of impaired digestion in which the fat of bacon is digested with perfect ease, where many other apparently more appropriate articles of food oppress the stomach for hours. It would be interesting and useful to ascertain, whether, in these cases, bile is present in the stomach, and also to discover in- dications by which we could predicate whether bacon will be suitable. As yet, although I have often seen the fact of bacon being easily digested by a weak stomach, I have not been able to
88 CHYME, ITS NATURE AND PROGRESS.
When bile is found with the gastric juice, the acid taste is diminished, and the flavour of the bile prevails in proportion to the quantity in the mixture.
The resulting compound of digestion in the stomach, or chyme, has been described as " a homogeneous, pulta- ceous, greyish substance, of a sweetish insipid taste, slightly acid," &c. In its homogeneous appearance, it is invariable ; but not in its colour ; that partakes very slightly of the colour of the food eaten. It is always of a lightish or 'greyish colour, varying in its shades and appearance, from that of cream, to a greyish or dark- coloured gruel. It is, also, more consistent at one time than at another ; modified, in this respect, by the kind of diet used. This circumstance, however, does not affect its homogeneous character. A rich and consistent quantity is all alike, and of the same quality. A poorer and thinner portion is equally uniform in its appearance. Chyme from butter, fat meats, oil, &c., resembles rich cream. That from farinaceous and vegetable diet, has more the appearance of gruel. It is invariably distinctly acid.
The passage of chyme from the stomach is gradual. Portions of chyme, as they become formed, pass out, and are succeeded by other portions. In the early stages, the passage of the chyme into the duodenum is more slowly effected than in the later stages. At first, it is more mixed with the undigested portions of aliment, and
distinguish by the symptoms, prior to experience, the cases in which it ought to be allowed. In many cases, it proves extremely indigestible. Possibly this may have some relation to the pre- s>ence or absence of bile— Editor.
MONTEGRE^S THEORY OF DIGESTION. 89
is probably separated with considerable difficulty by the powers of the stomach. In the later stages, as the whole mass becomes more and more chymified and fitted for the translation, the process is more rapid ; and is accelerated by a peculiar contraction of the stomach, a description of which will be found in the next section. It appears to be a provision of nature, that the chyme, towards the latter stages of its formation, should become more stimulating, and operate on the pyloric extremity of the stomach, so as to produce this peculiar contraction.
After the expulsion of the last particles of chyme, the stomach becomes quiescent and no more juice is secreted until a fi'esh supply of food is presented for its action, or some other mechanical irritation is applied to its internal coat.
Water and alcohol are not affected by the gastric juice. Fluids of all kinds are subject to the same exemption, unless they hold in solution or suspension some animal or vegetable aliment. Fluids pass from the stomach very soon after they are received, either by absorption or through the pylorus.
Since the general adoption of the theory of a specific solvent fluid, others have been proposed.
M. Montegre, who, it is said, had the power of vomit- ing at pleasure, performed a series of experiments on the fluids of the stomach obtained in this way, which in- duced him to come to a different conclusion on the sub- ject of digestion. " He conceives that what has been supposed to be the gastric juice, is in fact nothing but
H
90 DRS SMITH AND JACKSON's THEORIES.
saliva ; that it possesses no peculiar powers of acting on alimentary matter ; that the principal use of the gastric juice is to dilute the food ; and that the only action of the stomach consists in * une absorption vitale et elective/ in which the absorbent vessels, in consequence of their peculiar sensibility, take up certain parts of the food and reject others."*
A complete refutation of the conclusions drawn from the experiments of Montegre will be found in the fact, which has been tested by more than tvro hundred exa- minations and experiments made by me on the gastric cavity, that there never exists free gastric juice in the stomach unless excited by aliment or other stimulants. The fluid obtained by Montegre was, in all probability, a mixture of saliva (which had been unconsciously swal- lowed) and the mucus of the stomach. Neither of these secretions are capable of digesting aliment, nor could the peculiar products, generally obtained from the chemi- cal analysis of the gastric juice, be found in them.
The hypotheses proposed by Professors Smith and Jackson of this country, are modifications of Montegre's theory.
The former of these gentlemen supposes that digestion is performed "by the veins of the stomach and by the liver." He contends, " that the first step in the process of digestion is effected by the capillary veins originating in the villi of the stomach, with absorbing extremities, and terminating in the great branches of the vena portae ;"|
* Note in Bostock's Physiology, vol. ii. p. 384. •^ Essay on Digestion, p. 63.
DBS SMITH AND JACKSON's THEORIES. 91
that this action is continued through the small intestines ; that the absorbing veins take up the nutrient principles of the food, and reject, as excrementitious, the innutri- tions part ; that these nutrient principles are mixed with the returning blood within the cavity of the abdomen, and are carried into the liver, where the final processes of animalization and conversion into blood are completed.
Professor Jackson, in a recent work, has proposed a new theory, or rather revived, in some measure, the the- ory of maceration. His hypothesis, as nearly as can be collected from his work, is as follows : — He supposes that digestion is performed by submitting food to the action of diflPerent fluids, each of which has " solvent powers for different principles ;"* that the nutrient principles exist already formed in food, and are released from principles that are not required for nutrition, by a species of solu- tion, or maceration. The diflPerent fluids, as saliva, mu- cus from the mouth, throat, stomach, intestines, the bile and pancreatic juice, are the solvents of the diflPerent in- nutritive principles, and separate them from nutriment. He attributes great importance to the action of the sa- liva ; thinks it exercises a " very energetic operation on the food," &c., and denies, altogether, the existence of a specific solvent fluid.
It is unfortunate for the interests of physiological science, that it generally falls to the lot of men of vivid imaginations, and great powers of mind, to become res- tive under the restraints of a tedious and routine mode
* Principles of Medicine, founded on the Structure and Func- tions of the Animal Organism, p. 354.
92 DRS SMITH AND JACKSON's THEORIES.
of thinking, and to strikeout into bold and original hy- potheses to elucidate the operations of nature, or to ac- count for the phenomena that are constantly submitted to their inspection. The process of developing truth by patient and persevering investigation, experiment, and research, is incompatible with their notions of unrestrain- ed genius. The drudgery of science they leave to hum- bler and more unpretending contributors. The flight of genius is, however, frequently erratic. The bold and original opinions of Brown for a long time unsettled the practice of medicine ; and the later opinions of Montegre and others, have had a like effect on the sister science of physiology. It iS) however, a right, which men of genius possess, in common with others, to propose hypotheses, and to support them with such arguments and deductions as they may have in their power to bring. Great cau- tion and circumspection ought, however, to be observed.^ It is dangerous to unsettle long established truths ; for it is difficult to limit the extent of error. The gratifica- tion of a morbid desire to be distinguished as the propa- gator of new principles in philosophy, or as the head of a new sect, is not the only result to be expected from such heresies. New opinions or doctrines, whether true or false, will have admirers and followers, and will lead to practical results. And the errors of one man may lead thousands into the same vortex.
These, of course, are designed as general remarks ; and I have no wish to apply them, so far as bad motives are inferred, to the highly respectable gentlemen men- tioned above. Honest objections, no doubt, are enter-
DRS SMITH AND JACKSON's THEORIES. 9^
tained against the doctrine of digestion by the gastric juice. That they are so entertained by these gentlemen, I have no doubt. And I cheerfully concede to them the merit of great ingenuity, talents, and learning, in raising objections to the commonly received hypothesis, and ability in maintaining their peculiar opinions. But we ought not to allow ourselves to be seduced by the inge- nuity of argument or the blandishments of style. Truth, like beauty, when " unadorned, is adorned the most ;" and in prosecuting these experiments and inquiries, I be- lieve I have been guided by its light. Facts are more persuasive than arguments, however ingeniously made, and by their eloquence, I hope I have been able to plead for the support and maintenance of those doctrines, which have had for their advocates such men as Sydenham, Hunter, Spallanzani, Richerand, Abernethy, Broussais, Philip, Paris, Bostock, the Heidelberg and Paris Pro- fessors, Dunglison, and a host of other luminaries in the science of physiology.
( 94 )
CHAPTER VII.
OF THE APPEARANCE OF THE VILLOUS COAT, AND OF THE MOTIONS OF THE STOMACH.
Appearance of the villous coat— Gastric Papillae — Healthy aspect of the villous coat — Its aspect in disease — Motions in the sto- mach— Effects of — Order of contraction in the muscular fibres of the stomach — Passage of the chyme out of the stomach.
The inner coat of the stomach, in its natural and healthy state, is of a light, or pale pink colour, varying in its hues, according to its full or empty state. It is of a soft or velvet-like appearance, and is constantly co- vered with a very thin, transparent, viscid mucus, lining the whole interior of the organ.
Immediately beneath the mucous coat, and apparently incorporated with the villous membrane, appear small, spheroidal, or oval shaped, glandular bodies, from which the mucous fluid appears to be secreted.
By applying aliment, or other irritants, to the internal coat of the stomach, and observing the effect through a magnifying glass, innumerable minute lucid points, and very fine nervous or vascular papillae, can be seen arising from the villous membrane, and protruding through the mucous coat, from which distils a pure, limpid, colour- less, slightly viscid fluid. This Jiuid, thus excited, is in-
GASTRIC PAPILLA AND THEIR SECRETIONS. 95
variably distinctly acid. The mucus of the stomach is less fluid, more viscid or albuminous, semi-opaque, some- times a little saltish, and does not possess the slightest character of acidity. On applying the tongue to the mu- cous coat of the stomach, in its empty, unirritated state, no acid taste can be perceived. When food, or other irritants have been applied to the villous membrane, and the gastric papillae excited, the acid taste is immediately perceptible. These papillae, I am convinced fi'om ob- servation, form a part of what are called by authors, the villi of the stomach. Other vessels, perhaps absorbing as well as secretory, compose the remainder. That some portion of the villi forms the excretory ducts of the ves- sels, or glands, I have not the least doubt, from innume- rable ocular examinations of the process of secretion of gastric juice. The invariable effect of applying aliment to the internal, but exposed part of the gastric membrane, when in a healthy condition, has been the exudation of the solvent fluid, from the above-mentioned papillae. — Though the apertures of these vessels could not be seen, even with the assistance of the best microscopes that could be obtained, yet the points from which the fluid issued were clearly indicated by the gradual appearance of innumerable very fine lucid specks, rising through the transparent mucous coat, and seeming to burst, and dis- charge themselves upon the very points of the papillae, diffusing a limpid, thin fluid over the whole interior gas- tric surface. This appearance is conspicuous only during alimentation or chymifi cation. These lucid points, I have no doubt, are the termination of the excretory ducts
96 GASTRIC PAPILLAE AND THEIR SECRETIONS.
of the gastric vessels or glands, though the closest and most accurate observation may never be able to discern their distinct apertures.
The fluid so discharged, is absorbed by the aliment in contact, or collects in small drops and trickles down the sides of the stomach to the more depending parts, and there mingles with the food or whatever else may be contained in the gastric cavity. This fluid, the efficient cause of digestion — the true gastric juice of Spallanzani, I have no doubt— has generally been obtained, for expe- riment, by mechanical irritation of the internal coat of the stomach, produced by the introduction of a gum- elastic tube, through which it has been procured.
The gastric juice never appears to be accumulated in the cavity of the stomach while fasting ; and is seldom, if ever, discharged from its proper secerning vessels, except when excited by the natural stimulus of aliment, mecha- nical irritation of tubes, or other excitants. When ali- ment is received, the juice is given out in exact proportion to its requirements for solution, except when more food has been taken than is necessary for the wants of the system.
When mechanical irritation by a non-digestible sub- stance, as the elastic tube, stem of the thermometer, &c., has been used, the secretion is probably less than when the irritation has been produced by such substances as are readily dissolved in the gastric juice. Alimentary stimulus, when taken into the stomach, is diffused over the whole villous surface, and excites the gastric vessels generally to excrete their fluids copiously ; whereas the irritation of tubes, &c., is local, and produces only a par-
BEA^LTflY ASPECT OP THE VILLOUS COAT. 97
tial excitement of the vessels, and a scanty flow of the gastric juice. Hence the slowness in obtaining the clear fluid from the empty stomach through the tube. I have never, on numerous trials, been able to obtain at any one time more than one and a half or two ounces of this fluid after the stomach had disposed of its alimentary matters, however long the period of abstinence had been. The discharge of this small quantity has generally been ex- cited by the introduction of the tube. Ten, fifteen, or more minutes, were necessary to collect even this small quantity. Whenever fluid was obtained in larger quan- tity, as was sometimes the case, it invariably contained more than the usual quantity of mucus.
On viewing the interior of the stomach, the peculiar formation of the inner coats is distinctly exhibited. When empty, the rugae appear irregularly Tolded upon each other, almost in a quiescent state, of a pale pink colour, with the surface merely lubricated with mucus. On the application of aliment^ the action of the vessels is increased, the colour brightened, and the vermicular mO' tions excited. The small gastric papillae begin to dis* charge a clear transparent fluid (the alimentary solvent), which continues abundantly to aocumulate as aliment is r-eceived for digestion.
If the mucous covering of the villous coat be wiped off with a sponge or handkerchief during the period of chy- mification, the membrane appears roughish, of a deep pink colour at first ; but in a few seconds, the follicles and fine papillae begin to pour out their respective fluids, which being diffused over the parts abraded of mucus,
98 ITS APPEARANCE IN DISEASE.
restore to them their peculiar soft and velvet-like appear- ance, and pale pink colour, corresponding with the undis- turbed portions of the membrane, and the gastric juice goes on accumulating, and trickles down the sides of the stomach again.
If the membrane be wiped off when the stomach is emptjj or during the period of fasting, a similar rough- ness and deepened colour appear, though in a less de- gree, and the mucous exudation is more slowly restored. The follicles appear to swell more gradually. The fluids do not accumulate in quantity sufficient to trickle down^ as during the time of chymification. The mucous coat only appears to be restored.
The foregoing, I believe to be the natural appearances of the internal coat of the stomach in a healthy condition of the system.
In disease, or partial derangement of the healthy func- tion, this membrane presents various and essentially dif- ferent appearances.
In febrile diathesis, or predisposition, from whatever cause— obstructed perspiration, undue excitement by stimulating liquors, overloading the stomach with food — fear, anger, or whatever depresses or disturbs the nervous system — the villous coat becomes sometimes red and dry, at other times, pale and moist, and loses its smooth and healthy appearance ; the secretions become vitiated, greatly diminished, or entirely suppressed ; the mucous coat scarcely perceptible ; the follicles flat and flaccid, with secretions insufficient to protect the vascular and liervous papillae from irritation.
ASPECT OF VILLOUS COAT IN DISEASE. 99
There are sometimes found, on the internal coat of the stomach, eruptions or deep red pimples, not numerous, but distributed here and there upon the villous mem- brane, rising above the surface of the mucous coat. These are at first sharp-pointed and red, but frequently become filled with white purulent matter. At other times, irre- gular, circumscribed red patches, varying in size or ex- tent from half an inch to an inch and a half in circum- ference, are found on the internal coat. These appear to be the effect of congestion in the minute bloodvessels of the stomach. There are, also, seen at times small aphthous crusts in connection with these red patches. Abrasion of the lining membrane, like the rolling up of the mucous coat into small shreds or strings, leaving the papillae bare for an indefinite space, is not an uncommon appearance.
These diseased appearances, when very slight, do not always affect essentially the gastric apparatus. When considerable, and particularly when there are correspond- ing symptoms of disease, as dryness of the mouth, thirst, accelerated pulse, &c., no gastric juice can he extracted, not even on the application of alimentary stimulus. Drinks received are immediately absorbed, or otherwise disposed of, none remaining in the stomach ten minutes after being swallowed. Food taken in this condition of the stomach, remains undigested for twenty-four or forty- eight hours or more, increasing the derangement of the whole alimentary canal, and aggi'avating the general symptoms of disease.*
* These appearances of the villous coat and the non-secretion
100 Motions of the stomach.
After excessive eating or drinking, chymificatioH ig retarded ; and, although the appetite be not always im- paired at first, the fluids become acrid and sharp, exco- riating the edges of the aperture, and almost invariably produce aphthous patches, and the other indications of a diseased state of the internal membrane, mentioned above. Vitiated bile is also found in the stomach under these circumstances ; and floccvdi of mucus are much more abundant than in health.
Whenever this morbid condition of the stomach occurs^ with the usual accompanying symptoms of disease, there is generally a corresponding appearance of the tongue. When a healthy state of the stomach is restored, the tongue invariably becomes clean.
Motions of the Stomach. — With the anatomy of this organ, I have at present nothing to do ; it does not come within the limits which I have prescribed to myself. Its motions, as comprising a part of the process of diges- tion, I have endeavoured to observe as accurately as practicable, and I give the result.
The human stomach is furnished with muscular fasci- culi, so arranged as to shorten its diameter in every direc- tion. By the alternate contraction and relaxation of these bands, a great variety of motion is induced on this
of the gastric juice in feverish states of the system, are very im- portant in a practical point of view, and shew how injurious, and contrary to nature it is to insist on giving food in such circum- stances by way of supporting the strength. Drinks are useful, be- cause they are not digested but absorbed, and thus refresh the body ; but solid food taken into the stomach, can act only as an irritant where there is no gastric juice to digest it. — Editor.
MOTIONS OF THE STOMACH. 101
organ, sometimes transversely and at other times longi- tudinally. These alternate contractions and relaxations, when affecting the transverse diameter, produce what are called vermicular or peristaltic motions. The effect of the contraction of the longitudinal fibres, is to approxi- mate the splenic and pyloric extremities. When they all act together, the effect is to lessen the cavity of the stomach, and to press upon the contained aliment, if there be any in the stomach. These motions not only produce a constant disturbance, or churning of the con- tents of this organ, but they compel them, at the same time, to revolve around the interior from point to point, and from one extremity to another. In addition to these motions, there is a constant agitation of the stomach, produced by the respiratory muscles.
These contractions and relaxations of the nmscular fasciculi do not observe any very exact mode. Their motions are modified by various circumstances, such as the stimulant or non-stimulant property of the ingestae, the healthy or unhealthy state of the internal coat of the stomach, by exercise, and by repose, &c. &c.
The ordinary course and direction of the revolutions of the food, are first, after passing the oesophageal ring, from right to left, along the small arch ; thence, through the large curvature, from left to right. 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 smaller curvature, makes its appearance
102 MOTIONS OF THE STOMACH.
again at the aperture in its descent into the great curva- ture, to perform similar revolutions.
Such I have ascertained to be the revolutions of the contents of the stomach, from being able to identify par- ticular portions of food, and from the fact, that the bulb of the thermometer, which has been frequently intro- duced during chymification, invariably indicates the same movements. These revolutions are completed in from one to three minutes. They are probably induced, in a great measure, by the circular or transverse muscles of the stomach, as indicated by the spiral motion of the stem of the thermometer, both in descending to the pyloric portion and ascending to the splenic* These motions are slower at first than after chymification has conside- rably advanced.
While these revolutions of the contents of the stomach are progressing, the trituration or agitation is also going on. There is a perfect admixture of the whole ingestae, during the period of alimentation and chymification. There is nothing of the distinct lines of separation be- tween old and new food, and peculiar central or periphe- ral situation of crude, as distinguished from chymified aliment, said to have been observed by Philip, Magendie and others, in their experiments on dogs and rabbits, to be seen in the human stomach; at least in that of. the subject of these experiments. The whole contents of the stomach, until chymification be nearly complete, ex-
* The terms " descending " and " ascending," are used here, as well as in many other places, relatively, because the examina- tions were generally made while the man was lying on his right side«
EFFECT OF STOMACHIC CONTRACTIONS. 103
hibit a heterogeneous mass of solids and fluids ; hard and soft ; coarse and fine ; crude and chymified ; all inti- mately mixed, and circulating promiscuously through the gastric cavity, like the mixed contents of a closed vessel, gently agitated or turned in the hand.
If a mouthful of some tenacious food be swallowed, after digestion is considerably advanced, it will be seen passing the opening, to the great curvature ; and in the course of about one and a half or two minutes, it will re- appear, with the general circulating contents, more or less broken to pieces, or divided into smaller pieces ; and very soon loses its identity. This agitating motion has the eflPect, and is undoubtedly designed, to break up the bolus, as well as to separate the external and chymified portion of the particles of food, and allow the undigested portions to come in contact with the gastric juice, their proper solvent. If the motions were simply revolution- ary, the central portions would retain their situation, until the outer, or chymified part, had passed into the duodenum, in successive parcels ; which, it is evident, would very much retard the process of digestion.
As the food becomes more and more changed from its crude to its chymified state, the acidity of the gastric fluids is considerably increased— more so in vegetable than animal diet, — and the general contractile force of the muscles of the stomach is augmented in every direction ; giving the contained fluids an impulse towards the pylorus.
It is probable, that fi'om the very commencement of chymification — ^fi:om the time that food is received into the stomach — until that organ becomes empty, portions
104 EFFECTS OF STOMACHIC CONTRACTIONS.
of chyme are constantly passing into the duodenum, through the pyloric orifice, as the mass is presented at each successive revolution. I infer this from the fact that the volume is constantly decreasing. This decrease of volume, however, is slow at first ; but is rapidly ac- celerated towards the conclusion of digestion, when the whole mass becomes more or less chyraified. This ac- celerated expulsion appears to be effected by a peculiar action of the transverse muscles, or rather of the traTis- verse band, as described by Spallanzani, Haller, Cooper^ Sir E. Home, and others, in their experiments on ani- mals. This band is situated near the commencement of the more conieally shaped part of the pyloric extremity? three or four inches from the smaller end. In attempt- ing to pass a long glass-thermometer tube, through the aperture, into the pyloric portion of the stomach, during the latter stages of digestion, a forcible contraction is first perceived at this point, and the bulb is stopped. In a short time, there is a gentle relaxation, when the bulb passes without difficulty, and appears to be drawn, quite forcibly, for three or four inches, towards the pyloric end. It is then released, and forced back, or suffered to rise again ; at the same time giving to the tube a circular, or rather spiral motion, and frequently revolving it com- pletely over. These motions are distinctly indicated^ and strongly felt, in holding the end of the tube between the thumb and finger ; and it requires a pretty forcible grasp to prevent it from slipping from the hand, and be- ing drawn suddenly down to the pyloric extremity. When the tube is left to its own direction, at these periods of
EFFECTS OF STOMACHIC CONTRACTIONS. 105
contraction, it is drawn in, nearly its whole length, to the depth of ten inches : and when drawn back, requires con- siderable force, and gives to the fingers the sensation of a strong 5wc^zow-power, like drawing the piston from an exhausted tube. This ceases as soon as the relaxation occurs, and the tube rises again, of its own accord, three or four inches, when the bulb seems to be obstructed from rising further; but if pulled up an inch or two, through the stricture, it moves freely in all directions in the cardiac portions, and mostly inclines to the splenic extremity, though not disposed to make its exit at the aperture.
Above the contracting band, and towards the splenic portion of the stomach, the suction or grasping motion is not perceptible ; but when the bulb is pushed down to this point, it is distinctly felt to be grasped, and confined in its movements.
These peculiar motions and contractions continue un- til the stomach is perfectly empty, and not a particle of food or chyme remains ; when all becomes quiescent again.
If the bulb of the thermometer be suffered to be drawn down to the pyloric extremity, and detained there for a short time, or if the experiment be repeated too fre- quently, 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.
The peculiar contractions and relaxations, mention- ed above, succeed each other, at irregular intervals of
106 ORDER OF CONTRACTION IN THE
from two to four or five minTites. Simultaneously with the contractions, there is a general shortening of the fibres of the stomach. This organ contracts upon itself in every direction ; and its contents are compressed with much force. The valvular portion of the stomach is firmly thrust into the aperture, closing the orifice, pre- venting the egress of aliment, and obstructing the view of the interior. During the intervals of relaxation, the rugae perform their vermicular actions, the undulatory motions of the fluids continue, and the alimentary and chymous masses appear, revolving as before, promiscu- ously mixed, through the splenic and cardiac portions.
All these facts, taken together, will, I think, rationally admit of the following explanation. The longitudinal muscles of the whole stomach, with the assistance of the transverse ones of the splenic and central portions, carry the contents into the pyloric extremity. The circular or transverse muscles contract progressively, from left to right. When the impulse arrives at the transverse hand, 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. It appears that the crude food excites the con- tractile power of the pylorus, so as to prevent its passage into the duodenum, while the thinner chymified portion is'pressed through the valve, into the intestine. After the contractile impulse is carried to the pyloric extre- mity, the circular band, and all the transverse muscle s?
MUSCULAR FIBRES OF THE STOMACH. 107
become relaxed, and a contraction commences in a re- versed direction, from right to left, and carries the con- tents again to the splenic extremity, to undergo similar revolutions.
It would appear, then, that the discharge of the chyme from the stomach, is effected by mechanical impulse. But, I confess, I do not like to give an opinion. I state the circumstances as they have occurred. The idea of mechanical force, I admit, is liable to objection ; but, perhaps, not more so than that of the selecting power of the pylorus. Whatever bias I may have in favour of the former method, has been forced upon me by the deduc- tions of experiment and observation.
( 108 )
CHAPTER VIII.
OF CHYLIFICATION, AND THE USES OF THE BILE AND PANCREATIC JUICE.
Passage of chyme into the duodenum — and there converted into chyle by the agency of the bile and pancreatic juice — Chyle always the same in health — Changes occurring in the duo- denum.
As food becomes chymified by the gastric juice, the contractile motions of the stomach send it into the duo- denum to receive further changes preparatory to its assi- milation to the circulating fluids of the system by the lac- teal absorbents. It is at first slowly received into this organ from the stomach, but, during the later stages of chymification, its transmission becomes more accelerated. The duodenum is so constituted, that the passage of the chyme through it is considerably retarded ; and hence, in some pathological conditions of the system, the pres- sure on that organ from repletion is considerable, and frequently produces great pain and distress.
The vermicular motions of this and the other intes- tines are propagated from the stomach, and are con- tinued, after this organ has discharged all its contents, by the contained fluids, until the whole becomes assimi- lated. They are more or less rapid, varying at different sections of the canal, of which it is not necessary to par-
CONVERSION OF CHYME INTO CHYLE. 109
ticularize. These motions are excited by the stimulus of the chyme, and occur at intervals, on the introduction of each quantity passed through the pylorus.
The chymous mass is not changed until it arrives at, or passes the mouth of, the ductus choledochus, when the liver and pancreas are excited to discharge their re- spective fluids. These mix with the chyme, and pro- duce an essential alteration in its sensible and chemical properties. At this point the lacteal absorbents com- mence.
That the change from a chymous to a chylous stage, is effected by the operation of the bile and pancreatic juice, there can be no doubt. Of the nature of this change there is some diversity of opinion. Chyle is ge- nerally described as " a white opaque substance, con- siderably resembling cream in its aspect and physical properties," * though it is said to vary slightly, accord- ing to the kind of aliment which had been used. It is my impression, however, that pure chyle, taken from the lacteals of a healthy subject, and produced by natural food, is invariably the same substance in the same indi- vidual. Changes that have been observed must be reckoned as the effect of a pathological state of the sys- tem, or the absorption of a non-digesting substance. Me- dicines and other substances, which are not capable of digestion, are sometimes taken up by the lacteal absorb- ents, and may produce an alteration in the physical and chemical properties of chyle. It is possible that a small* proportion of oil may escape the action of the digestive * Bostock's Physiology, vol. ii. p. 392.
1 10 IN HEALTH CHYLE IS ALWAYS THE SAME.
apparatus, be absorbed by the lacteals, and produce the opaque, white colour, mentioned by authors as some- times appearing. Countenance is given to this sugges- tion by the fact, that the more opaque-coloured parts of chyle are found floating on the surface, and that it is al- ways discovered after the ingestion of oily food. At other times it is uniform in its colour and consistence, whatever colouring matter may have been contained in the food.
I wish to be understood to say, that every species of aliment produces the same kind of nutrient principles. With the view of attempting an investigation of this sub- ject, as has been previously mentioned, I instituted some imperfect experiments and examinations. From the re- sult, see Experiments, Second Series, from 47th to 56th. By the addition of bile and dilute muriatic acid, and sub- sequently pancreatic juice, to chyme formed in the arti- ficial way, as well as in the stomach, it separated into three distinct parts, a reddish-brown sediment at the bot- tom, a whey-coloured fluid in the centre, and a creamy pellicle at the top. Each repetition of the experiment produced a similar result, though not exactly alike in all. The central portion I suspect to be imperfectly-formed chyle. The sediment, fi'om its appearance and the coarseness of its particles, I judge is incapable of being acted on or taken up by the absorbents ; the creamy or oily pellicle is not only liable to the same objection, but is in too small proportion to the ingesta. The fluid part is fitted, by its fluidity, for the ready action of the ab- sorbents, and is, moreover, in sufficient quantity for the
CHANGE WHICH OCCURS IN DUODENUM* 111
purposes of nutrition. The change of colour and con- sistence is probably effected in the lacteal glands and vessels. The sediment and pelHcle, I apprehend, are both excrementitial. The " irregular filaments" attached to the valvuiae conniventes, mentioned by Magendie, and which he concluded to be imperfectly-formed chyle, were undoubtedly portions of the creamy pellicle found in the experiments referred to.
But what is the nature of the changes effected in the duodenum ? Aliment, after being introduced into the stomach, is dissolved in the gastric juice, and forms a new compound with this fluid. The constituent ele- ments of food are various. When compounded with the gastric juice, they may, nevertheless, be said to form a simple compound, or a gastrite of aliment. I am indiffe- rent about terms ; and this will as well convey my mean- ing as any other. When this gastrite is introduced into the duodenum, and mixed with the hepatic and pancrea- tic fluids, are we not warranted, from all the facts that have been observed, in saying, that there is a general play of chemical affinities in that organ, separating the nutrient principles, and forming various new compounds from the elements of each ? The chymous mass changes its colour, and loses its acidity. There is a sensible ex- trication of gas, as observed by Magendie and others.* In the stomach oxygen is found mixed with a small pro- portion of hydrogen. In the intestines an increased pro- portion of hydrogen exists, with carbonic acid, nitrogen,
• The escape of gas is generally observable in mixing these fluids with chyme in my experiments.
112 CHANGE WHICH OCCURS IN DUODENUM*
kc.f but no oxygen. Does not the acid of the chyme unite with the alkalis of the bile, and form new com- pounds ? And do not other equally important changes take place ? This subject, I confess, is obscure, and per- haps will not admit of a very perfect investigation.
The constant agitation which is maintained in the in- testines preserves the chyle in a state of perfect admix- ture with the other fluids until absorption has taken place. By standing at rest the separation mentioned above is evident and perfect.
It has been supposed that the mucus of the intestines has some agency in the formation of chyle. But I am disposed to think with Professor Dunglison and others, that the use of the mucus is to lubricate the in- ternal coat of the intestines, and perhaps to dilute their contents.
It has been suggested that digestion can be perfected in the duodenum and lower bowels when the food has not been submitted to the action of the stomach and its fluids. In two experiments by Magendie, one failed, and the other was attended with partial success. Too much reliance ought not to be placed on experiments that re- quire such severe and cruel vivisections as were resorted to in these cases. It is possible, as suggested by Dun- glison, that the presence of crude aliment in the duo- denum may excite the discharge of gastric juice in the stomach, its expulsion into the duodenum, and its conse- quent action on the food, before it is affected by the bile and pancreatic juice. Or it may be that the upper part
CHANGE WHICH OCCURS IN DUODENUM. 113
of the duodenum is furnished with vessels which secrete a fluid similar to gastric juice.
Experiments have also been instituted with the view of ascertaining whether chyle can be formed without the admixture of the hepatic and pancreatic fluids with vari- ous results. Brodie ascertained, bj' tying the ductus communis choledochus in young cats, that the process of chylification was prevented, and that no chyle was found in the intestines. Magendie, Leuret, and Lassaigne, on tying this duct, discovered matter of " a rosy yellow co- lour," which afforded, on analysis, the same constituents of chyle, although the animals which were the subjects of the operation had been kept some time without food. There is certainly an apparent discordance in these re- ports. But it is possible they may be explained and reconciled. It is well known that the absorbents are ac- tive during a protracted fast (as in these last experi- ments), and are constantly taking up the cellular sub- stance, for the purpose of supplying the bloodvessels with these broken-up solids of the system. Emaciation is the effect of absorption. The lacteals, like other ab- sorbents, have undoubtedly their appropriate stimulus ; but, if that be withholden, they will feed on other sub- stances, the cellular and other solid parts within their reach. If such be the case, it will account for the rosy- coloured fluid found in the lacteals by Magendie and others.
K
EXPERIMENTS AND OBSERVATIONS, &c.
EXPERIMENTS, &a
FIRST SERIES.
EXPERIMENT 1.
August 1. 1825 — At 12 o'clock, a.m., I introduced through the perforation, into the stomach, the following articles of diet, suspended by a silk string, and fastened at proper distances, so as to pass in without pain — viz. : — a piece of high seasoned a la mode beef, a piece of raio salted fat pork, a piece of raw salted lean beef, a piece of boiled salted beef a piece of stale bread, and a bunch of raw sliced cabbage ; each piece weighing about two drachms ; the lad continuing his usual employment about the house.
At 1 o'clock, P.M., withdrew and examined them — found the cabbage and bread about half digested ; the pieces of meat unchanged. Returned them into the stomach.
At 2 o'clock, P.M. withdrew them again — found the cabbage, bread, pork, and boiled beef all cleanly digest- ed,* and gone from the string ; the other pieces of meat
* These experiments are inserted here, as they were originally taken down in my note-book, with very little alteration of phraseo-
118 EXPERIMENTS ON THE DIGESTION
but very little affected. Returned them into the stomach again.
At 2 o'clock P.M.* examined again — ^found the a-la- mode-beef partly digested ; the raw beef was slightly macerated on the surface, but its general texture was firm and entire. The smell and taste of the fluids of the sto- mach were slightly rancid ; and the boy complained of some pain and uneasiness at the breast. Returned them again.
The lad complaining of considerable distress and un- easiness at the stomach, general debility and lassitude, with some pain in his head, I withdrew the string, and found the remaining portions of aliment nearly in the same condition as when last examined ; the fluid more rancid and sharp. The boy still complaining, I did not return them any more.
August 2. — The distress at the stomach and pain in the head continuing, accompanied with costiveness, a depressed pulse, dry skin, coated tongue, and numerous white spots, or pustules, resembHng coagulated lymph, spread over the inner surface of the stomach, I thought it advisable to give medicine ; and, accordingly, dropped into the stomach, through the aperture, half a dozen calomel pills ^ four or five grains each; which, in about three hours, had a thorough cathartic effect, and removed
logy, and none of the sense. Subsequent experiments have some- times convinced me of errors in former ones. When this has been the case, I have generally made the corrections in the way of re- marks, or observations, as in this experiment.
• There is evidently an error in repeating the same hour here ; but it is impossible to correct it — Editor.
OF A MIXED MEAL. 119
all the foregoing symptoms, and the diseased appearance of the inner coat of the stomach. The effect of the me- dicine was the same as when administered in the usual way, by the mouth and oesophagus, except the nausea commonly occasioned by swallowing pills.
Remarks, — This experiment cannot be considered afair test of the powers of the gastric juice. The cabbage, one of the articles which was, in this instance, most speedily dis- solved, was cut into small fibrous pieces, very thin, and necessarily exposed on all its surfaces to the action of the gastric juice. The stale bread was porous, and, of course, admitted the juice into all its interstices ; and probably fell from the string as soon as softened, and before it was completely dissolved. These circumstances will account for the more rapid disappearance of these substances, than of the pieces of meat, which were in entire solid pieces when put in. To account for the disappearance of the fat pork, it is only necessary to remark, that the fat of meat is always resolved into oil, by the warmth of the stomach, before it is digested. I have generally ob- served that when he has fed on fat meat or butter, the whole superior portion of the contents of the stomach, if examined a short time after eating, will be found covered with an oily pellicle. This fact may account for the dis- appearance of the pork fi-om the string. I think, upon the whole, and subsequent experiments have confirmed the opinion, that fat meats are less easily digested than lean, when both have received the same advantages of comminution. Generally speaking, the looser the tex-
120 EXPERIMENTS ON
ture, and the more tender the fibre, of animal food, the easier it is of digestion.
This experiment is important, in a pathological point of view. It confirms the opinion, that undigested por- tions of food in the stomach produce all the phenomena of fever ; and is calculated to vrarn us of the danger of all excesses, where that organ is concerned. It also ad- monishes us of the necessity of a perfect comminution of the articles of diet.
EXPERIMENT 2.
August 7. — At 11 o'clock, a.m., after having kept the lad fasting for seventeen hours, I introduced the glass - tube of a thermometer (Fahrenheit's) through *the perfo- ration, into the stomach, nearly the whole length of the stem, to ascertain the natural warmth of the stomach. In fifteen minutes, or less, the mercury rose to 100°, and there remained stationary. This I determined by mark- ing the height of the mercury on the glass with ink, as it stood in the stomach, and then withdrawing it, and placing it on the graduated scale again.
I now introduced a gum-elastic (caoutchouc) tube, and drew off one ounce of pure gastric liquor, unmixed with any other matter, except a small proportion of mucus, into a three ounce vial. I then took a solid piece of boiled^ recently salted beef, weighing three drachms, and put it into the liquor in the vial ; corked the vial tight, and placed it in a saucepan filled with water, raised to the temperature of 100°, and kept at that point, on a nicely regulated sand-bath. In forty minutes digestion had distinctly commenced over the surface of the meat
DIGESTION OUT OF THE STOMACH. 121
\xi fifty minutes the fluid had become quite opaque and cloudy ; the external texture began to separate and be- come loose. In sixty minutes chyme began to form.
At 1 o'clock p. M. (digestion having progressed with the same regularity as in the last half hour), the cellular texture seemed to be entirely destroyed, leaving the muscular fibres loose and unconnected, floating about in fine small shreds, very tender and soft. At 3 o'clock, the muscular fibres had diminished one half, since last exa- mination at 1 o'clock. At 5 o'clock, they were nearly all digested ; a few fibres only remaining. At 7 o'clock, the muscular texture was completely broken down, and only a few of the small fibres floating in the fluid. At 9 o'clock, every part of the meat was completely digested.
The gastric juice, when taken from the stomach, was as clear and transparent as water. The mixture in the vial was now about the colour of whey. After standing at rest a few minutes, a fine sediment of the colour of the meat subsided to the bottom of the vial. ^
Experiment 3.
August 7. At 1 1 A. M. I suspended a piece of heej\ exactly similar to that in the vial (Ex. 2.), into the sto- mach, through the aperture. At 12 o'clock m. withdrew it, and found it as much affected by digestion as that in the vial ; there was little or no difference in their appear- ance. Returned it again. At 1 o'clock p.m. I drew out the string, but the meat was all completely digested and gone.
122 EXPERIMENTS ON
Remarks. — The effect of the gastric juice on the piece of meat suspended in the stomach, was exactly similar to that in the vial, only more rapid after the first half hour, and sooner completed. Digestion commenced on, and was confined to, the surface entirely in both situations. Agi- tation accelerated the solution in the vial, by removing the coat that was digested on the surface, enveloping the remainder of the meat in the gastric fluid, and giving this fluid access to the undigested portions.
Experiment 4.
August 8. — At 9 o'clock a.m., I drew off an ounce and a half of gastric juice into a three ounce vial, sus- pended two pieces of boiled chicken, from the breast and back, into it, and placed it in the same situation and tem- perature as in the second experiment, observing the same regularity and minuteness.
Digestion commenced and progressed much the same as in the second experiment, but rather slower : Xhefowl appearing to be more difficult of digestion than thejiesk. The texture of the chicken being closer than that of the beef, the gastric juice appeared not to insinuate itself into the interstices of the muscular fibre so readily as into the beef, but operated entirely upon the outer surface, dis- solving it as a piece of gum-arabic is dissolved in the mouth, until the List particle was digested.
The colour of the fluid, after digesting the chicken, was of a greyish-white, and more resembled a milky fluid than whey, which was the colour of the chyme from the beef.
DIGESTION OUT OF THE STOMACH. 123
The contents of both vials, kept perfectly tight, re- mained free from any fcetor, acidity, or offensive smell or taste, from the time of the experiments (7th and 8th August) to the 6th of September ; at which time, that containing the solution of boiled beefhecdime very offen- sive and putrid ; while that containing the chyme from the boiled chicken was perfectly bland and sweet. Both were kept in exactly similar situations.
Remarks. — It is perhaps unnecessary to make any com- ments on the result of the above experiments. Each one will make up his opinion from the facts. These demonstrate, at least, that the stomach secretes a fluid which possesses solvent properties. The change in the solid substances is effected too rapidly to be accounted for on the princi- ple of either maceration or putrefaction. I shall be able to shew, in some of the following experiments, that ali- ment undergoes the same changes in the stomach as are effected in the mode here adopted.
The young man who was the subject of these experi- ments, left me about this time (September 1825) and went to Canada, the place of his former residence. The experiments were consequently suspended.
( 124 )
SECOND SERIES.
Fort Crawford, Upper Mississippi, ^■^71^20. 1829.
Alexis St Martin having returned from Canada, after an absence of nearly four years, with his stomach in the same or very similar condition as when he left me in September 1825, I continued to prosecute the gastric experiments which were commenced before he left me.
With a view to ascertain the variations of temperature, if any there were, in the interior of the stomach, under different circumstances and conditions of the system, and vicissitudes of the atmosphere, I instituted the following experiments.
Experiment 1.
December 6. 1829. At 9 o'clock a.m. I introduced the glass-tube of a thermometer (Fahrenheit's) through the artificial opening into the stomach, in a healthy and empty condition, nearly the whole length of the stem. In six or eight minutes, the mercury became stationary at 98°. Weather cloudy, damp, and almost raining ; ground wet, muddy, and thawing. Wind south and mild. Ther- mometer, in a north exposure, 63°. Commenced rain-
ON THE TEMPERATURE OF THE STOMACH. 125
ing at 1 1 o'clock a. m. and continued all day, with op- pressive atmosphere.
Experiment 2.
December "J. — Introduced thermometer at the same hour as yesterday — circumstances of stomach the same. Mercury at 98°. Weather cloudy ; atmosphere damp ; wind N. W. and light ; thermometer 27°.
Experiment 3. December 8. — Introduced thermometer at 9 o'clock A. m. — circumstances of stomach same as yesterday. Mercury stationary at 99°. Weather clear ; atmosphere dry ; wind S. W. and light ; thermometer 13°.
Experiment 4.
December 9. — Introduced thermometer at 9 o'clock, A. M — circumstances similar. Mercury stationary at 99°- Weather clear ; atmosphere dry ; wind W. and light ; thermometer 10°.
Experiment 5.
January 24. 1830. — Introduced thermometer at 3 o'clock p. m. Weather clear and cold ; thermometer 8° below 0 ; wind N. W. and light ; stomach empty and coats healthy. Mercury stationary at 100°.
Experiment 6.
January 25. — Introduced thermometer at 8 o'clock a.m. Weather clear; wind S. W. and light; thermo- meter 2° ; stomach empty. Mercury stationary at 100°.
126 ON THE TEMPERATURE OF THE STOMACH.
At 10 o'clock A.M. (one hour after eating a breakfast of pork and bread) introduced thermometer again. Mer- cury stationary at 100°, as at 9 o'clock, before eating.
Experiment 7.
March 17. — At 10 o'clock a.m. introduced thermo- meter. Weather rainy and foggy ; wind S. W. and Hght ; thermometer 38° ; stomach empty, having eaten nothing since 7 o'clock last evening. Mercury station- ary at