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CARTER. 1837. Entered, according to Act of Congress, in the year 1837, By T. H. CARTER, in the Clerk's Office of the District Court of Massachusetts. KIDOER k. WRIGHT. PRINTERS, 32 Congrm Street. CONTENTS. PAGE Introduction.................. 9 CHAPTER I. General remarks on nutrition and digestion, 11 Nutrition, page 11.—Digestion, 14.—General view of the alimentary canal in the higher order of animals, 17. CHAPTER II. Mastication and insalivation.—taste, ... 20 Mastication in the inferior animals, 20.—Teeth of man, 24.—Mastication and insalivation in man, 25.—Taste, 32. CHAPTER III. Deglutition, ................. 36 Description of the oesophagus, 37.—Physiology of deglutition, 38. CHAPTER IV. Function of the stomach, ......... 43 Description of the stomach, 43.—Conversion of the food into chyme, 46. IV contents. CHAPTER V. Function of the stomach concluded, . . . Former hypotheses of chymification, 50.—Modern theory of the function of the stomach, 52.—Des- cription of the gastric liquor, 53. — Chemical properties of the gastric liquor, 54.—Action of the gastric juice on alimentary substances out of the stomach, 57.—The gastric juice does not act on living matter, 58.—Solvent power of the gastric liquor on different substances, 59.—Influence of the muscular contractions of the stomach in for- warding chymification, 60.—Manner in which the gastric fluid unites with the food, 61.—Is chymi- fication limited to any particular portion of the stomach ? 61.—Passage of the aliment into the intestines, 62. CHAPTER VI. Chvlification or second digestion,...... Description of the small intestine, 64.—Structure of the liver, 66.—Function of the liver, 68.— Pancreas, 71.—Spleen, 72.—Phenomena which take place in the duodenum, 75. CHAPTER VII. Passage of the chyle and refuse portion of the food through the small intestine, &c. . Lacteal absorbents, 78.—Description of the chyle, 81.—Absorption of the chyle, 82.—Passage of the residual matter, and its dismissal from the body, 84.—Influence of food in the stomach upon the general system, 87.—Passage of fluids from the stomach, 90. contents. V CHAPTER VIII. PAGB Hunger and thirst,............. 92 Definition of appetites, 92.—Hunger, 92.—Causes of hunger, 94.—Phenomena of hunger when ex- treme, 98. — Voracity, 99.—Fasting, 101.__ Thirst, 104. CHAPTER IX. General remarks on the food of animals, 109 General division of animals founded on the nature of their food, 110.—Comparative structure of the digestive organs in carnivorous and phytivorous animals, 114.—Rumination, 117.—Omnivorous animals, 121. CHAPTER X. Food of man,.................123 Nutritive principles of vegetable food, 148.—Nutri- tive principles of animal food, 149.—Condiments, 155. DYSPEPSIA, OR THE DISORDERS OF DIGESTION. CHAPTER XI. Definition of dyspepsia, and general remarks upon its nature, ................160 VI contents. CHAPTER XII. PAGE History of the symptoms of dyspepsia, . . 167 Local phenomena. State of the tongue and mouth, 16S.—Symptoms manifested in the throat, 170.— Symptoms disclosed in the stomach, 170.—Symp- toms in the bowels, 176.—Influence of the disease on the urinary secretion, 178.—State of the appe- tite for food, 179.—Affection of the appetite for drink, 181. CHAPTER XIII. Symptoms of dyspepsia continued,.....182 Sympathetic or induced symptoms, 182.—Sympa- thy explained, 182.—Condition of the skin, 188.— Influence of dyspepsia on the vital energies of the constitution, 190.—Symptoms manifested in the head, 192.—Effects of morbid digestion on the mental feelings and operations, 193.—Manifesta- tions of dyspepcia in the nervous system, 197. CHAPTER XIV. Symptoms of dyspepsia concluded,.....203 Influence of indigestion upon the sleep, 203.-Night- mare, 206.—Peculiarities marking that form of dyspepsia resulting from the use of ardent spirits, 211.—Duration and course of dyspepsia, 215. CHAPTER XV. Causes of dyspepsia,.............220 Constitutional predisposition to indigestion, 220.— Early foundation of dyspepsia, 221.—Periods of life most favorable to dyspepsia, 223.—Influence CONTENTS. Vll of the weather, and impure air in the production of indigestion, 224.—Deficient exercise, 227.— Excessive bodily labor, 229.—Influence of par- ticular postures of the body in producing indiges- tion, 231.—Excessive and premature mental labor, 232.—Errors in diet, 235.—Rapid eating, 239.—Deficient nourishment, 241. CHAPTER XVI. Causes of dyspepsia continued,...... . 242 Distilled spirits, 242.—Fermented liquors, 243.— Tea, 245.—Coffee, 248.—Tobacco, 249.—Abuse of medicine, 253.—Constipation of the bowels, 257.—Insufficient and irregular sleep, 257.— Long continued nursing, 259. CHAPTER XVII. Causes of dyspepsia concluded, ......259 Mental affections and passions, 259.—Concluding remarks on the causes of dyspepsia, 280. CHAPTER XVIII. Treatment of dyspepsia,...........282 Preliminary observations, 282.—General remarks on the diet suitable in dyspepsia,288.—Regularity in eating, 292.—Frequency of eating, 292.—A solid meal is not to be eaten when the body is fatigued, nor to be followed by any severe exercise, 294.—A solid meal should not be taken when the mind is suffering under fatigue or agitation, 296. —Quantity of food to be taken, 297.—Food should be rendered grateful to the palate, 298.—Drinks, 299.—Quantity, 299.—Character, 300. V1U CONTENTS. CHAPTER XIX. PAGE Treatment of dyspepsia continued, .... 303 Breakfast, 303.—Dinner, 307.—Evening meal, 315. —Fruits, 317. CHAPTER XX. Treatment of dyspepsia continued,.....320 General observations upon exercise, 320.—Particu- lar modes of exercise, 327.—Walking, 328.— Dancing, 331.—Equitation, 334.—Riding in a carriage, 336.—Sailing, 336.—Swinging, 339.— Friction of the body, 339.—Management of the mind, 339. CHAPTER XXI. Treatment of dyspepsia continued.....341 Journeying, 341.—Conditions of the atmosphere most favorable in dyspepsia, 343.—Change of air, 345.—Clothing, 346.—Sleep, 346.—Bath- ing, 349.—Cold bathing, 351.—Warm bathing, 353.—Tonics, 355. Conclusion, ...................356 INTRODUCTION. The purpose of the following treatise is to present,—in a form so far divested of the technical language of medicine as to come within the comprehension of all classes of the reading community,—a history of the phenomena, causes and treatment of dyspepsia, founded upon a gen- eral acquaintance with the physiology or healthy function of the organs which it implicates. There are few disorders which occasion a larger sum of moral and physical suffering among us than those of digestion, and probably none whose pre- vention and cure are so directly dependent upon a prudent adjustment of our habits in relation to diet, and the general regimen of life, the principles of which, all may, and ought to understand. So intimately is the health of the digestive organs associated with that of the general system, that a treatise on their derangements must necessarily comprehend a pretty full consideration of the 2' X INTRODUCTION. different principles which relate to the preservation of health; thus air, exercise, diet, the moral affections &c., will all be brought under notice. Active medicinal agents being seldom called for in ordinary instances of dyspepsia, and never being admissible save under the immediate direction of a medical adviser, will only be noticed in the present volume with the view to discoun- tenance their employment, and thus save from the hurtful consequences which I am convinced too frequently result from an unadvised resort to them. Waiving all apologies, usual on such occasions, for the publication of the present treatise, well knowing that if worthy, it will require none, and if unworthy, none will be received, I will now, without further preface, leave it to tell its own story. PHYSIOLOGICAL HISTORY OF DIGESTION. CHAPTER I. GENERAL REMARKS ON NUTRITION AND DIGESTION. Nutrition.—Destruction and renovation are ne- cessary conditions of vital action. A continued interchange of substance is going on in living be- ings from the beginning of their existence to its close in death. Nature but loans us her materials for a little term, when she resumes them for some new appropriation in her vast storehouse. Mutation, though most remarkably characteristic of life, yet belongs to every department of nature. A constant transmigration of matter is essential to the present order of our globe. Thus common or mineral matter receives life in the vegetable—and through it, as a connecting link, in the animal—and 12 GENERAL REMARKS ON then may undergo a round of circulation in diffe- rent animal bodies, and sooner or later resume its pristine state. Nutrition is steadily furnishing our bodies with fresh materials, while those which have already answered their destination in the economy, are re- moved by absorption, thence conveyed into the cir- culation, and finally, separated from it and dis- charged by the different drains or emunctories of the system, as the skin, kidneys, lungs, and bow- els. To these phenomena of composition and de- composition, or of building up and tearing down, all the organic vital actions are directly or indirectly contributing. During the whole period of existence then, though without our consciousness, a ceaseless order of ex- penditure and supply is proceeding in our bodies under the directing influence of that mysterious principle, that Promethean fire, termed life. Many of the ancients—influenced probably of the Pytha- gorean doctrine of numbers, seven being a favorable one in this system—asserted that the human fabric experienced an entire renewal every seven years. Others again, have allowed only three years for such a metamorphosis. But we have no fixed data for calculations of this sort. Every physiologist well knows that the rapidity with which this permutation of particles is accomplished, is deter- mined by the activity of the circulation, and consequent energy of life, which vary materially in different parts and structures of the body, and -tat NUTRITION. 13 even in the same, under different circumstances. Thus while some organs may undergo a complete renovation in a few months, many years may be required to effect it in others; and some structures, as the enamel of the teeth, perhaps continue per- manently unchanged. Furthermore, waste and repair must, under ordinary circumstances, progress more speedily in the strong and active, than in the feeble and indolent. This indeed is sufficiently shown by the greater amount of supplies demanded by the former. Nutrition varies in its force at different periods of life, and in different constitutions; and at the same period, and in the same constitution under different influences, as of sleep and watching, the moral affections, exercise and rest, the activity of the excretions, &c. It is influenced, too, in a striking manner, by external temperature. In high northern latitudes it becomes remarkably energetic, and there being less waste of the materials of the body than in warmer climates, an abundance of fat—indicating an excess of nutrition—is commonly deposited. We note this especially in northern animals, and fat, being a bad conductor of heat, serves them as a defence against the rigor of their weather. In our own climate also, during winter, the appe- tite is usually more keen, and our bodies when in good health, become more full than in the warm months of summer. We may hence infer the importance of much physical exertion in cold 2* 14 GENERAL REMARKS ON climates and seasons to insure a due relation between composition and decomposition; as like- wise to augment the supply of animal heat, and to determine the blood, which the cold tends to concentrate internally, to the surface of the body. Thus when the inhabitants of high latitudes, are active and temperate, they arrive at the greatest degree of physical vigor of which the human frame is susceptible—and hence the general course of conquests has been from north to south. Digestion.—We may define digestion to be that process, or rather series of processes, by which the individuality of the food is destroyed, and its nutritious principle separated, and rendered fit to be transmitted to, and identified with the blood, for the purpose of supplying the needful expenditure of this fluid in nutrition, and its associate functions. Or, if I may so speak, it accomplishes the first changes on the raw material, which is ultimately to be wrought into the fabric of our bodies. Every living body, to maintain its active existence, must transform foreign matter into its own sub- stance, but the manner in which this is effected varies materially in its complexity in the different gradations of life. Plants have no distinct digestive organs; they are generally fixed to the soil, and when in an active state, are, by means of their roots and the pores on their surface, constantly absorbing nutnmental materials, which are elaborated in their vessels. But all animals, however humble their position in the scale of life, exhibit some form DIGESTION. 15 of an alimentary cavity, into which the food is first received, and where certain changes are to be wrought upon it. Cuvier asserts that he is acquainted with no animal unfurnished with such a cavity, and many naturalists regard it as the best means of distinguishing the animal from the vegetable, where the two kingdoms run close upon the confines of each other. Indeed the animal, different from the vegetable, generally having the power of locomotion, and receiving nourishment at intervals only, requires some distinct receptacle for his food. By the plant then the aliment is absorbed directly from the soil into its circulation. By the animal it must first be received into a cavity, and from thence, after having experienced certain necessary changes, be absorbed into the blood- vessels. Hence the alimentary canal bears to the animal a relation somewhat analogous to what the soil, from whence it imbibes its nourishment, does to the vegetable. The humblest animal existence yet known, and which the microscope only can discover to us, is found among the infusoria, or infusory animals, so called because they appear to be produced by the infusion in water, of animal or vegetable substances. The simplest animal of this class is merely a minute vesicle or bladder, inclosing a transparent fluid, without any opening to receive its food, and is hence supposed, like the plant, to be supported by simple imbibition. Yet it exhibits a distinct 16 GENERAL REMARKS ON DIGESTION. cavity, and probably,—for all here is uncertainty, —nourishment may be absorbed through the deli- cate walls into its interior, and there undergoing some digestive change, be again absorbed and converted into the substance of this animated vesicle. As observed in regard to the vegetable, it is uniformly in contact with, and may be con- stantly imbibing its aliment. The most simple form, however, of a digestive organ with which we can consider ourselves acquainted, is witnessed in the lowest order of polypes, denominated, from their resemblance to a purse, bursarice. These animals represent a mere sac or pouch, with a single opening answering both for the reception of food, and for the discharge of its excrementitious portion. If turned inside out, their two surfaces exchange functions. We see then animal life beginning as a simple alimentary cavity—proving how essential it is—and rising by the superaddition of other organs. Ascending in the scale of life, we observe the machinery of digestion growing more and more complex, advancing step by step to perfection— part after part being added, till at last may be enumerated organs for seizing and breaking down or masticating the food—for swallowing it—for transforming it into chyme, and next into chyle,— for the absorption of this chyle into the blood, and lastly for the evacuation of its refuse or excremental parts. VIEW OF THE ALIMENTARY CANAL. 17 Man is rightly placed at the head of the animal creation, since viewing him as a whole, his struc- ture and functions, are superior to those displayed by any other class of beings. But this is not equally true when considered in reference to his individual parts. Though life rises by gradations to its most perfect state, yet the advance is not necessarily uniform in each of its particular organs. Thus, anatomically viewed, man, in respect to his digestive organs, has no pre-eminence over many other animals of his order. In some, even, as among the ruminants, or those which chew the cud, they are far more extensive and complicated than in him. Many physiologists, however, imagine that in man they have a superior devel- opement of nervous force. General view of the alimentary canal as it exists in the higher order of animals.—This continuous canal, which affords passage to our aliments, and prepares them to nourish the body, is commonly described as beginning at the superior orifice of the stomach; but since in man, at least, some change appears to be wrought in the food by its commix- ture with the fluids of the mouth,—not. to be sure, absolutely essential to digestion, yet probably facilitating it—I shall consider it as commencing at this orifice. It will comprehend then, the mouth, including the passage immediately behind the tongue, usually denominated the fauces—the oeso- phagus or gullet, the stomach, and the small and large intestines. 18 GENERAL VIEW OF THE The intestinal division is variously convoluted on itself, and economically packed up in the cavity below the chest, named the abdomen. In the human animal, the intestines may be stated gener- ally to be from five to six times the length of the individual. Meckel, from numerous admeasure- ments, found them very irregular in their length, varying in different persons from thirteen to twenty- seven feet, without any proportional difference in the stature of the body. In childhood they are often ten or even twelve times longer than the body, a great amount of nourishment being needed at this period to support the growth of the system. The alimentary canal is of various dimensions in different parts. Sometimes representing a nar- row tube, then swelling into the form of a pouch or sac. I may remark that each division of this canal is capacious at its commencement, where the most important operations of digestion are performed, but soon contracts into a continuous tube. Thus the mouth, fauces, and pharynx, or upper portion of the oesophagus, form one large cavity representing the commencement of the first division of the ali- mentary canal, and here copious secretions are furnished, and in the mouth the important opera- tions of mastication and insalivation are effected. This cavity in its descent narrows into the oeso- phagus. The oesophagus having proceeded for a certain distance, seems suddenly to expand to form the stomach, which may be viewed as the com- ALIMENTARY CANAL. 19 mencement of the second division of the canal, or of the small intestine. How important are the actions which here take place on the food will be seen in the sequel. The small intestine, which is the narrow tube extending from the stomach, terminates its course in another enlargement, called the ccecum, and which is the beginning of the last division of the canal, or great intestine. In the ccecum, important influences are exerted on the residue of the food chiefly preparatory to its dis- missal from the body in the character of feces. With these general views I will now proceed to a somewhat more particular description of the different parts, with their offices, associated in the process of digestion. 20 MASTICATION IN THE CHAPTER II. MASTICATION AND INSALIVATION.--TASTE. Mastication and insalivation consist in the tearing, bruising and triturating of the food in the mouth, and the mingling of it with the fluids there secreted, preparatory to its reception into the stomach. Mastication in the inferior animals.—Organs of mastication are by no means universal in the in- ferior departments of animate beings. Some in- sects, moluscous animals, vermes, &c., take their food by suction; and again, in other animals, or- gans of suction and mastication both exist. Those even of the highest class, at the first period of their existence, receive their nutriment by suction alone, hence their name—mammalia.* And indeed their organs of ingestion ever after remain capable of acting as organs of suction, and are frequently thus employed. Drinking, in many of the mammalia, * This class of animals are brought forth alive, and all of them during infancy, obtain their support by means of suction, from the mammae, or paps of their mother. rNFERIOR ANIMALS. 21 is uniformly accomplished by suction, and often- times in our own species, as in sipping. In this class, however, more numerous organs are con- cerned in its performance, as the lips, cheeks, tongue, in union with the instruments of respiration, and it therefore becomes a more complicated operation than in the aforementioned less elevated animals. We here witness an interesting repetition in the superior, of the earlier and inferior animal forma- tions. " We find," says, Dr. Cams, "a remarka- ble proof of the accuracy of the principle of a gradually progressive developement of organiza- tion, in the fact, that the new-born Child, a,s regards the mode of ingestion of nutritive matter, re- approximates to the inferior Classes of Animals, and wanting teeth receives its nutriment by Suction, like a Polype or a Worm."* It might be added, too, that at the other extreme of life, the jaws be- coming toothless like those of the infant, and the diet being necessarily of a more fluid character, suction is in part again resorted to. But this is not the only example of an approximation to in- ferior animal existences noticed in the two extremes of our being. In infancy our mode of progression is like that of the quadruped, on our four extremities. The energies of the human frame require a certain measure of developement before we can walk erect in the full dignity of our nature. And as we near * Comparative Anatomy of Animals. Translated from the German, by R. T. Gore, vol. 2, p. llU. 3 22 MASTICATION IN THI^ the last boundary of life, and the animal powers, preparatory to their final extinction, decline, the body bends forward, the centre of gravity is changed, and a staff is needed for support, and thus again we incline to the position of the quad- ruped. Referring to the mode of progression, it has been not unaptly said—I believe by some French physiologist—that the transient state of man, is the permanent state of the inferior animal. The organs of mastication vary much in their character and arrangement, and occupy different situations in the different tribes of animals. In fishes the teeth are diversely arranged in the mouth, pharynx, oesophagus and stomach. In the carp, for example, they are in the pharynx, in the sucker, lobster, crab and others, in the stomach; and some fishes, as the sturgeon, are utterly desti- tute of them. Certain insects have, also, their teeth in the stomach. Birds have no teeth, their crops and gizzards producing effects on the food analogous to those of mastication. The crop more particularly belongs to birds which feed on grains, but likewise exists in many which are strictly flesh eaters. It is a large membranous cavity or pouch, susceptible of great distension, situated at the lower part of the gullet, into which the aliment is received when swallowed, and where, being exposed to a high temperature, and the dissolving influence of the secreted fluids, it undergoes a maceration, and its texture becomes softened. INFERIOR ANIMALS. 23 The gizzard, in birds which feed on grains, or hard food, is a small cavity, with thick and power- ful muscular walls, lined with a compact and callous membrane. It possesses great mechanical power, and like the strong molar teeth of many of the mammalia, crushes the most dense sub- stances. In birds of prey, or such as feed on flesh, it is thinner and weaker, more resembling a mem- branous stomach. Many birds, for the purpose, as is thought, of contributing to the mechanical effect of the gizzard, or to serve as temporary teeth, are in the practice of swallowing coarse sand and gravel stones, and some will not thrive when excluded from such substances. The ostrich swallows glass, nails, or indeed almost any bodies, however hard and rough, which are presented to him, and probably not from mere stupidity, as many suppose, but the force of a natural instinct. Spallanzani introduced artificially into the giz- zards, or muscular stomachs of birds, sharp needles and lancets, and without injury, they being quickly blunted and crushed by the mechanical power of the organs. In the mammalia, owing to difference in the character and arrangement of their teeth, mastica- tion exhibits remarkable modifications. It is gen- erally accomplished in the mouth, yet there are exceptions. Thus the ant-eaters have no teeth, but like granivorous birds are furnished with a powerful muscular stomach, and are said also to 24 TEETH OF MAN. swallow stones to assist in breaking down their food. Some of the mammalia have teeth for gnawing and cutting, others for seizing, holding and lace- rating, and others again, for crushing and grinding, and in different orders of this class, these varieties will be found more or less combined, in corres- pondence with their peculiar dietetic habits. Teeth of man.—Three descriptions of teeth be- long to the human species. First, the incisors or cutting teeth,—the four front ones in each jaw. They are broad, and flat, with a sharp, cutting edge, and shut over each other like the blades of a pair of scissors. Second, the cuspidati, or spear-shaped teeth, called also, canine or dog-teeth, and eye-teeth. Of these there are two in each jaw, placed next in order to the incisors. They have been thought to resemble the tusks of the flesh-eating animals, as of the dog for example, and from hence have derived one of their names. Third, the molar or grinding teeth, under which general name all the remainder may be comprehended. With the mode of action and use of these last, every one must be familiar. Let it not be understood, however, that man is peculiar in possessing these three kinds of teeth; for they belong to very many other animals, and who differ greatly in their habits of diet. The monkey family approximate more closely toman in the form and arrangement of their teeth than any other known animals. "It is only in Man, however," says Mr. Gore, «that the three MASTICATION AND INSALIVATION. 25 kinds of teeth are arranged in an uninterrupted series, so that those in one jaw every where touch the corresponding teeth in the other; a fossil Genus of Animals (Anoplotherium) alone resem- bling him in this respect. In Apes and Carnivora, and in all species where the Canine are longer than the other teeth, there is at least a vacancy in each jaw for the canine tooth of the other."* Dr. Carus also speaks of this same arrangement as being proper to man. Mastication and insalivation in man.—During the mechanical action of mastication, particularly when the food is dry, the secretions of the mouth are greatly augmented, and blending with the morsel effect what is termed insalivation. The fluids subservient to mastication are mucus, and saliva. The former is supplied by the membrane lining the mouth, called, from its secretion, mucous membrane. This same membrane, modified in its character in different parts, forms a continuous lining for the whole alimentary canal, and every where secretes the like mucous fluid, sheathing its own delicate texture, allowing foreign substances to glide easily over it, and subserving also, other important ends in the different processes of diges- tion. The membrane is remarkably smooth and soft, and in many situations has a velvet-like appearance, or displays a delicate pile, from which latter character it has received the additional name * Carus' Comparative Anatomy—Note to p. 77th, of volume 2d. 3* 26 MASTICATION AND INSALIVATION of villous coat. It appears to be but a continuation of the external skin, which may be seen gradually assuming its characters when turning into the internal cavities, as in the lips for example; hence it has been sometimes called the internal skin, and when, as under certain circumstances, it is long exposed to the atmosphere, a cuticle forms upon it, and it approaches in its aspect and functions to the true covering of the body. Could the mucous membrane and skin then exchange situations, it is not impossible that they might, in a measure at at least, exchange characters. The other secretion, or saliva, is far more copi- ous, and, as usually considered, more important than the mucus. This is supplied by distinct glands, named salivary, from the fluid they pre- pare. The perfect glands, to which class these belong, are organs varying in their size and ap- pearance, but generally affecting a somewhat spherical shape, which form out of the blood, fluids resembling it perhaps in none of their sensi- ble qualities, and which, with the exception of the secretion of the kidneys, are destined to some useful purpose in the economy. They are fur- nished with a duct, called excretory, which re- ceives their peculiar fluids when prepared, and conveys them to the situations where their agency is needed. Some have connected with them a bag or reservoir, into which their secretions are partly or wholly conducted, thus the gall bladder is IN MAN. 27 attached to the liver, and the urinary bladder to the kidneys. Excited by their specific stimuli, or by common mechanical irritation, or under the influence of the imagination merely, the glands straightway emit their proper fluids. But how they accomplish their work—how they obtain from the blood sub- stances so unlike it in character, as bile, tears, saliva, &c, physiology has yet failed to explain. The salivary secretion is naturally called forth by the mechanical action of mastication, and the stim- ulus of food to the sense of taste. Yet the sight, smell, or even thoughts of savory food, when one is hungry, will literally cause the mouth to water. Thus let a piece of meat be held before a hungry dog and the saliva will often be seen streaming from each side of his mouth. Sometimes on the contact of sapid substances with the mouth, this fluid is emitted with a sudden jet, and to some distance, from the ducts of its glands. Acrimonious and disgusting articles taken into the mouth, greatly augment it—and the passions, as will hereafter be shown, exercise a marked influence both upon its quantity and qualities. Saliva is a limpid, tasteless, inodorous and some- what viscid fluid. Its constituents are water, which forms its chief proportion—a peculiar ani- mal matter—mucus—a very little pure soda, and some alkaline muriates, especially the muriate of potash—and lactate of soda. 2S MASTICATION AND INSALIVATION It has been estimated that upwards of eight ounces of saliva are secreted during an ordinary meal. Dr. Gairdner, speaking of the case of a man who had cut through the oesophagus, informs us that during a meal consisting of broth injected through the divided gullet into the stomach, from six to eight ounces of saliva were discharged. Here the secretion must have been excited by the stimulus of food to the stomach merely. The amount of saliva however, will of course vary according to the nature and quantity, of the food, and the degree of mastication. It is comparatively greater in childhood than in adult life ; and there are good reasons, too, for supposing that a vegeta- ble, calls for a larger relative quantity of saliva than an animal diet. Thus comparative anatomy teaches that the salivary glands are most developed in the herbivorous species of the mammalia, as also in those birds which feed exclusively on vege- tables. In the mouth then the morsel being broken down and formed into a pulpy mass, and acquiring the temperature of the body, is prepared for degluti- tion. Some physiologists, as Haller for example, have thought that the more volatile particles of the nutriment are absorbed from the mouth during mastication, and contribute in some slight decree to nutrition. The uses of the saliva have been differently stated. Some have regarded it merely serviceable as any other bland fluid might be, to soften the IN MAN. 29 food, and lubricate its passages to favor degluti- tion ; while others ascribe to it a more specific influence, believing that some vital change is wrought on the food in the mouth constituting the first step in the series of digestive phenomena. The inferences of Dr. Beaumont on this subject, drawn from his curious and interesting experi- ments on a young Canadian who had a fistulous opening into his stomach,* are—" That digestion is * Dr. William Beaumont of the American army was called upon in 1822 to treat a young Canadian (Alexis St. Martin) eighteen years of age, for a severe and extensive wound of his left side—and which had completely penetrated into the stomach—from the accidental discharge of a musket. In about a year the wounded parts had become restored, only that the perforation into the stomach remained unclosed. Over this opening, which was about two inches and a half in circumference, the subject was at first compelled to wear a compress to prevent the escape of the food, but erelong a sort of valve formed out of the inner or mucous coat of the stomach, which opening inward only, securely retained the food during digestion. By pressing open this valve, and distending the orifice, the interior of the stomach could, to a certain extent, be actually inspected. Here then a most favorable opportu- nity presented for a series of experiments on the interesting subject of digestion, and one which it appears was not neglected. Dr. Beaumont having prosecuted his experiments for several years with a praiseworthy zeal and judgment, laid an account of them before the public in a dis- tinct volume, entitled " Experiments and Observations on the Gastric Juice, and on the Physiology of Digestion.'' From Dr. Beaumont's inferences from his experiments, I shall often have occasion to quote in the course of the present volume. Though we have on record other cases of fistulous openings into the stomach, yet this case was in a special manner favorable for physiological experiment, inasmuch as the subject enjoyed remarkably good health. 30 MASTICATION AND INSALIVATION facilitated by minutness of division and tenderness of fibre and retarded by opposite qualities." " That the processes of mastication, insalivation and deglutition, in an abstract point of view, do not, in any way, affect the digestion of food; or in other words, when food is introduced directly into the stomach in a finely divided state, without these previous steps, it is as readily and as perfectly digested as when they have been taken. :' That saliva does not possess the properties of an alimentary solvent. " That the first stage of digestion is effected in the stomach." Still I am inclined to the belief that the saliva especially, is requisite to the function of digestion, and that its place could be adequately supplied by no other fluid. The care with which nature has provided for its preparation, and the copious secre- tion of it uniformly elicited even from the stimulus of food to the stomach, afford strong grounds for inferring that it is no unimportant agent in the function I am considering. Furthermore, in instances of wounds about the face and throat, so situated as to occasion an undue waste of saliva, loss of appetite, and indigestion uniformly ensue. "Ruysh knew a man who was wholly deprived of his appetite by a fistula in one of the salivary ducts; and it is well known to the physician who has attended maniacal patients, that the constant spitting in which such persons occasionally in- dulge, is invariably attended with loss of appetite, IN MAN. 31 dyspepsia, and emaciation."* The habit then which many persons fall into, of throwing away the fluids of the mouth, in addition to its vulgarity, cannot but be prejudicial to health. Haller makes the remark, that by wellbred people the saliva is for the most part swallowed. From the preceeding remarks the importance of slow and thorough mastication in lightening the task of the stomach may readily be deduced. The simple destruction of cohesion, and softening of the alimentary substances, must facilitate the union with them of the fluids of the stomach, just as the like processes favor purely chemical combinations. Spallanzani took two pieces of mutton, each weigh- ing forty-live grains, and having chewed one as much as he was accustomed to chew his food, enclosed them both in separate hollow metallic spheres having perforations to admit the digestive fluids of the stomach. These were both voided at the same time, and of the masticated meat there remained only four grains, while of that which had not been masticated there were eighteen left. Those articles whose cohesion cannot be easily overcome, and which, of course, but imperfectly mingle with the fluids of the mouth, as new, and doughy bread, or any tenacious and glutinous substances, are uniformly indigestible in delicate * Paris on diet. 32 TASTE. stomachs. The principal cause why stale, is more easy of digestion than fresh bread, is probably its greater friability; or more brittle texture, which is favorable to mastication, and the consequent action of the stomach. It will now, I trust, easily be conceived how digestion may become disordered from imperfect mastication, whether owing to rapid eating, defective teeth, or other causes. Taste.—The sense of taste is perceived in the mucous membrane of the mouth and fauces, and fading insensibly, vanishes someAvhere in the pha- rynx or upper portion of the oesophagus. In birds, who do not masticate, it probably extends further; and may not the greediness, and apparent pleasure with which many swallow hard and dry grains, be in anticipation of agreeable impressions to be experienced in their crops, or even gizzards? In those animals, too, which chew the cud, may not this sense be enjoyed in the first and second* stomach ? the latter, at least, is capable of volun- tary action, the power of which in man is always combined with sensation. An impression associated with taste, and which may be regarded but as a continuation of it, is perceived in the back part of the nostrils. Mr. Mayo speaks of this impression as being popularly referred to the palate, while in reality it is felt on the sentient membrane of the nostrils; thus the fume of certain kinds of food ascending into the cavities of the nose, occasions this distinct sensation : " in administering medicine to children,"—says this TASTE. 33 physiologist—" it is well known that the greater part of what is disagreeable in its flavor may be avoided by closing the nostrils while the draught is swallowed: and by repeating this experiment upon various articles of food, it is easy to ascertain how much of their flavor depends upon one sense, and how much is appreciated by the other. Hence it is that the senses of taste and smell have been often compared as having a resemblance, the odor of many substances being supposed to resem- ble their flavor; while the fact is, that the flavor of such bodies consists in their scent, and that the two impressions, which are compared, are one and the same." * It is through the intervention of taste, that the demands of hunger become the occasion of pleasure, and the needful supply of nutriment is thus more certainly secured. This sense varies in its delicacy in different parts of the mouth. The lips have it only in a very slight degree, their province seeming more especially to judge of the temperature of the ali- ments. In the tongue, particularly at its tip or extremity, taste is remarkably vivid, and apparently even more so in some of the inferior animals than in man. Thus those which live on herbage are furnished with a long tongue, by means of which they very readily discriminate noxious or salutary * Outlines of Physiology, p. 313. 4 34 Taste. qualities belonging to the different varieties among' which they feed. The taste, in union with the smell, which latter is in many very acute, direct the brute creation to their appropriate food, and probably in their native and unrestrained condition—their saving instincts uncorrupted by art—wholesome food alone would be agreeable to these senses, and thus would they be faithful sentinels to the stomach. In man, however, the taste is for the most part so perverted by luxury, and the numerous inven- tions of cookery necessarily associated with it, that it is far from being a safe guide in respect to diet; and it would probably be difficult to find two individuals in whom the standard of agreeable and disagreeable in relation to food would precisely correspond. In reality, our physical, vary nearly as much as our moral tastes. Other things being equal, too, this sense would appear to be less trusty in the human than in the brute animal; the former depending on the uncertain guidance of reason, while the latter is more obedient to his unerring instincts. Thus instances occur of young children eating cicuta, stramonium, and other poisonous herbs ; and adults, too, not unfrequently mistake noxious for wholesome substances ; but the inferior animal is by no means liable to such errors. Individuals, as in regard to their other senses, differ naturally in the vividness of taste, and con- sequently in the enjoyment which it affords them. It is also susceptible of a high degree of cultiva- TASTE. 35 tion, and thus the epicure gets to distinguish savors almost as accurately as the musician does sounds, or the painter, colors. Hence cooking is an art ever held in high estimation when society has advanced to a state of luxury and refinement; it seems, I may almost say, to go hand in hand with the fine arts. The habitual employment of acrid and stimula- ting food and drink blunts and corrupts the taste, so that simple and wholesome substances become insipid. The too imiform impressions from the same kind of food may also after a time weary the sense, and fail to impart pleasure. Healthful and agreeable excitement, in most of our organs, is to a certain extent dependent on variations hi their stimuli. It is sameness that brings ennui, and the tadium vita, so frequent among mankind. It is essential to the perfection of taste, that its organs be moist, and the food softened, or partially dissolved, that it may come into extensive and close contact with the extremities of the nerves of this sense. These conditions are all insured by masti- cation. During this process, the food, beside being partly liquefied, is moved about the mouth, com- pressed between the tongue and palate, thus becom- ing generally and intimately applied to the different portions of the mucous membrane of the mouth, which is abundantly furnished with the nerves of taste. But it is in swallowing, when the different parts of the mouth and fauces are all contracting 36 DEGLUTITION. themselves upon the morsel, that the pleasure of eating is at its acme. The taste varies in its intenseness at different periods of life. In childhood, the system demand- ing frequent supplies of nourishment to contribute to its growth, this sense is particularly keen. In old age it diminishes in acuteness, and more sapid substances are commonly required to arouse it. Still its failure by no means corresponds with that in the other senses; but being necessary to exist- ence, it continues to afford enjoyment even to its final term; seeming like the last solitary link which ties the old man to the pleasures of earth. The taste is modified by climate and season, and by the different conditions, and often, wants of the system. It is affected in almost all diseases, but in a more especial manner by such as implicate the digestive function. CHAPTER III. DEGLUTITION. The food having undergone its needful alterations in the mouth, is next to be conveyed into the oeso- phagus, and through it to the stomach DESCRIPTION OF THE (ESOPHAGUS. 37 Description of the oesophagus.—The oesophagus, commonly called the gullet, is a straight, cylin- drical, narrow and fleshy tube, forming a passage from the mouth to the stomach. It consists of three membraneous coats. The first or outer is composed chiefly of cellular texture, but having no immediate and obvious concern in the function of the organ, its description is not required. The second, middle, or muscular coat, comprises two distinct layers of muscular fibres—one, or the external, running lengthwise of the tube—the other, or internal, encircling it like rings; hence they are called the longitudinal and circular fibres of its middle coat. It is plain now that the contraction of the external layer of fibres must shorten the tube, while that of the internal or circular will contract it, both of which actions are necessary to the passage of the food. The inner or mucous coat is a continuation of the lining of the mouth, and secretes a mucous or lubricating fluid, over which the aliments readily slide. This, compared with the other coats, having but little elasticity or power of distension, is necessarily more extensive, and hence displays a number of longitudinal folds, which become developed to correspond with the great dilatation to which the other more elastic coats are so fre- quently subjected, especially in those persons who eat in a hurry, and swallow huge mouthfuls. At the superior part of the oesophagus is the pharynx, a broad funnel-shaped expansion of the 4* 38 PHYSIOLOGY OF DEGLUTITION. tube,—commonly described as a distinct division of it—continuous with the fauces, or straits of the mouth just behind the tongue. Into the pharynx, open the nasal passages, and the upper portion of the windpipe, named the larynx. The oesophagus enters the stomach at its left or larger extremity, by what is called, from its vicin- ity to the heart, the cardiac orifice. Physiology of deglutition.—When the food is to be swallowed, it is collected on the tongue, which is then raised,—brought into the condition of an inclined plane, and pressing itself continuously from its tip to its root against the roof of the mouth, and some other muscles at the same time aiding by their contractions, the morsel is necessarily forced back into the fauces. The pharynx next rises upward and forward to receive it, and the openings into the nostrils and air-tube are shut. The nasal passages are closed by the soft palate, or that curtain of flesh continued posteriorly from the palate bones or roof of the mouth, and which may be easily seen by looking into this cavity; and when the food is passing these openings, this is elevated and applied to them like a valve. Whenever, either originally, or from disease, the soft palate is imperfect, swallowing must be per- formed slowly and with great care, otherwise the food will find its way into the nostrils; and fur- thermore, as under such circumstances, the passage of air through these cavities cannot be controlled, PHYSIOLOGY OF DEGLUTITION. 39 articulation is imperfect, and the voice has a disa- greeable nasal sound. The windpipe is guarded by the contraction of its aperture, and also by the epiglottis. This latter is a thin elastic cartilage, shaped like a little tongue, extending over the top of the air-pipe, and which, pressed down by the food, shuts over its orifice like a valve. The pharynx having received the morsel, pushes it onward to the narrow part of the gullet, or oeso- phagus proper, through which, by the agency of its circular and longitudinal muscular fibres,—the former contracting it from above downward, the latter shortening it, or, as it were, drawing it over the food—it is conveyed into the stomach. Sub- stances then do not pass down the oesophagus simply by the force of their own gravity, but are urged along by a foreign impulse. Many animals habitually swallow with their head downwards, and man is capable of doing the same ; indeed he has been known to swallow even liquids while standing on his head. Deglutition has been divided into three stages.— The first comprehending the passage of the aliment from the mouth to the pharynx ; the second, from the pharynx to the oesophagus, and the third, from the oesophagus to the stomach. The second stage must be rapid, since during it the respiration is wholly interrupted. Thus if at this period we attempt to speak or breathe, or laughter from any cause is excited, the aperture of the windpipe is 40 PHYSIOLOGY OF DEGLUTITION. unclosed, and portions of the food or drink neces- sarily falling into it, a convulsive cough, accompa- nied with a sense of strangulation instantly supervene, and we say, what is literally true, that the food has gone down the wrong way. It is in this manner that foreign substances, as beans, &c., will sometimes, particularly in children, get into the air-tube, when it may become necessary to make an artificial opening into it for their removal. We may now readily understand how substances, too large for deglutition, becoming impeded in the pharynx, endanger speedy suffocation. Arrived in the oesophagus, the progress of the food becomes much more tardy, and it is not unfre- quently subjected to delays here which would be fatal in the previous stage of its passage. In the first step of deglutition the various parts of the mouth and fauces where the sense of taste resides, are brought into intimate and forcible con- tact with the sapid body, and hence during it, the pleasure of eating is at its height, and it may thus be termed the orgasm of taste. When therefore the appetite is good and the food agreeable, we eat with avidity—and it is with difficulty even that the inclination to swallow luscious articles is resisted. But under the reverse circumstances, deglutition takes place much more slowly. Every one knows how painful it is to swallow nauseous drugs, and how long, children will often retain them in their mouth before they can be urged to do it—and oftentimes force alone will impel them. Sometimes PHYSIOLOGY OF DEGLUTITION. 41 it is utterly impossible, the pharynx contracting spasmodically against their passage. Whenever too the stomach is afflicted with nausea, deglutition becomes unpleasant, and is often very difficult to be accomplished. In. swallowing we remark the gradual transition of the sensitive and voluntary functions into those which are insensible and involuntary. I may here briefly state for the information of such as are unacquainted with the principles of physiology, that all animals are constituted of two classes of functions. One they have in common with vege- tables, the other is peculiar to themselves. The former are denominated the vegetable, nutritive, or organic functions, and comprehend digestion, circulation, absorption, nutrition, secretion, &c, and being immediately essential to life, are with- drawn from the direct domain of the will, — a power too uncertain and capricious for their super- intendence. Imagine the circulation and respiration to be wholly subject to volition, and how quickly must life cease! These functions, too, when in health, go on independent of our consciousness—sensation indeed is unnecessary to them, it being an associate of, and a motive to volition. The latter class, are both voluntary and sensitive, and comprise the mental feelings and operations, spontaneous muscular motions, and the functions of the different senses. 42 PHYSIOLOGY OF DEGLUTITION. These two sets of functions however, are not always separated by very distinct boundaries, so that the exact point where they may be said to begin or terminate cannot in every instance be confidently decided upon. Some of our functions, too, partake of the character of both classes. Res- piration, for example, being immediately necessary to life, continues without volition or consciousness; yet under the influence of the will, it can be increased, diminished, interrupted, and modified in a variety of ways. In the different processes of digestion, phenomena of both divisions of the functions are likewise dis- played, and we may here observe their gradual transition. Thus mastication and the first stage of deglutition, or the transmission of the food from the mouth to the pharynx, are spontaneous, and associated with feeling, and the specific sensation of taste. The second stage, or the passage of the food through the pharynx, though less decidedly, still is in a certain measure voluntary, the aid of the will being wanted to hasten the morsel over the aperture of the air passage. We can sometimes, too, by a spontaneous effort, repel our aliments in this stage of their progress. In the pharynx, common sensation, and specific, or taste, are both very slight. When the food has arrived in the oesophagus, the voluntary, appear wholly to have yielded to the organic contractions, and unless the mass is relatively large, or hard and rough, or acrid, or of a temperature varying considerably DESCRIPTION-OF THE STOMACH. 43 from that of the body, its progress continues with- out our recognition. But as the refuse of the nutriment Comes near to the outlet of the system, sensation is again excited, and voluntary actions are called forth for its dismissal. The mucous membrane then of the alimentary canal, ever as it approaches the skin, acquires the power of distinct sensation, and its functions become associated with voluntary actions. Let it be borne in mind that I am now speaking of the digestive function when in health. CHAPTER IV. FUNCTION OF THE STOMACH. It is the important province of the stomach to transform the alimental matters into a peculiar substance termed chyme. Description of the stomach.—In the human body, as in all the higher animals, there are three great cavities, each containing organs, which, though differing remarkably in their structure and offices, 44 DESCRIPTION OF are absolutely essential to existence. The superior is that of the cranium and includes the brain, upon which we depend, not only for life, but for all the noble functions of our nature. The next in order is the cavity of the thorax, where are the heart and lungs, without whose offices existence must at once cease. The third, or inferior, is the abdominal cavity, and here we find the organs of digestion, with which we are especially concerned. A thin, flat muscle, with a tendinous centre, called the diaphragm or midriff, divides the abdo- men from the chest, forming as it were, the roof of the former, and the floor of the latter. Just under this partition, and in contact with it, is the stomach. The oesophagus descending through the chest along the backbone, passes an opening in the dia- phragm, and then appears suddenly to expand into a large bag, which is the stomach. Or to use the more common description, the gullet having perfo- rated the diaphragm, enters the stomach by the cardiac orifice near its left or great extremity. The stomach represents a conical sac curved upon itself, and is commonly likened to the pouch of a bagpipe—a very happy comparison for those who are familiar with this instrument. It is situ- ated obliquely across the upper part of the abdomen, diminishing, and descending a little from left to right, and hence its right extremity is much smaller, and somewhat more dependent than its left. In the former situation, or, regarding its conical shape—at its apex, is the outlet into the THE STOMACH. 45 intestines, called the pyloric orifice, encircled by a ring of muscular fibres, and furnished with a sort of fold in the mucous membrane which has been compared to a valve,—a construction supposed to have reference to the retention of the food while it is undergoing its preparation for the intestines. The stomach is constructed of three coats, or layers of membrane. The external is thin, shining, dense and transparent, and because it exhales a moist vapor which when condensed into fluid is called serum, it has received the general name of ssrous membrane. The same membrane exists in the other great cavities, and indeed in various parts of the body, though with some modifications of character, and under different names. Thus in the chest it is called pleura, and in the abdomen, peritoneum, from a Greek word meaning to extend round. In this latter situation then, where we are concerned with it, it is called indiscriminately serous or peritoneal coat, and it here both lines the walls of the cavity, and invests more or less perfectly all its viscera. The obvious use of this membrane is to keep the organs externally moist and pliable, to prevent their adhesion, and facilitate their move- ments upon each other. It likewise strengthens the substance of the stomach, and also of the other abdominal viscera, and assists in confining them to their respective situations. The next, or middle, is a muscular coat, and upon it the necessary contractions - of the organ depend. Like the corresponding coat of the oeso- 5 46 CONVERSION OF THE phagus, it has a longitudinal and circular layer of fibres for shortening and narrowing the stomach. It is most powerful at the two orifices, probably to control the egress of the food. The inner, is a mucous coat, continuous with that of the oesophagus, but more soft and velvet-like. As if it were too large for the organ, it displays frequent plaits or wrinkles, called rugae, which are unfolded in proportion as the stomach is distended, thus supplying a want of elasticity, a property enjoyed in so high a degree by the two other coats. By such an arrangement also, a more extensive surface is afforded to furnish the important digestive secretions. This membrane, ever when in health, is sheathed and moistened by a mucous fluid, essential to the wellbeing of the stomach, and probably also an important agent in the conversion of the food into chyme. The organ under consideration is largely supplied with nerves and blood-vessels, as is the case with all parts which have important functions to perform. Its capacity varies of course in different individuals; in an adult, in its natural state, it will generally hold from three to four pints, yet it may be so distended as to contain one or two gallons. Conversion of the food into chyme.—The aliments having been submitted to the influence of the sto- mach for a period varying in duration according to circumstances, are transformed into chyme. This, though differing somewhat in its color and consist- ence, may be described generally as a greyish FOOD INTO CHYME. 47 white, pulpy or nearly fluid substance. It has a peculiar acid, combined with a slightly sweetish taste, and a sharp or pungent odor. Its sensible qualities however are liable to considerable modi- fications from the nature of the diet employed. The time expended by the stomach in transform- ing an ordinary meal into chyme, is most commonly stated to be from four to five hours. Dr. Beau- mont found the usual period required by the subject of his experiments for the disposal of a moderate meal of the fibrous parts of meat, with bread, &c., to be from three to three and a half hours. This subject, it should be remembered, was a very active and vigorous young man, and a native of a cold climate. It is plain however that the time thus occupied must be influenced by a variety of cir- cumstances. Some persons have constitutionally a quick, while others have a slow digestion; hence, all other things being equal, the process may be completed in half the time in one individual that will be required for it in another. Different kinds of food will of course experience this change with greater or less celerity. We find it very commonly asserted that flesh, having a nearer similitude to our own substance, calls for less alteration to be transformed into it, than vege- table matter, and consequently for a less compli- cated and protracted operation of the stomach. But were this explanation true, raw meat should be more digestible than cooked, and human flesh the most so of any substance. Broussais found 48 CONVERSION OF THE that milk and fecula were more speedily trans- formed into chyme than meat. Still the digesti- bility of different kinds of food must depend greatly on habit, and constitution, and also on their diffe- rent modes of preparation. A variety of incidental circumstances, moreover, influence the facility of the process under consider- ation. Thus it is hastened by a proper mastication of the food, a keen appetite, happy feelings, and moderate exercise in a pure and cool atmosphere. Exercise taken immediately after eating is gen- erally thought to impede chymification; in support of which opinion no experiment is more often cited than that of Professor Harwood of Cambridge, in England. This gentleman fed two dogs,—nearly alike in age, health and appetite—with equal quantities of meat; and while one was permitted to indulge in his propensity to quietness and sleep, the other was taken into the fields, and kept at the severe exercise of hunting game. At the expiration of some hours both were killed and their stomachs opened; when it appeared that the food in the dog which had remained at rest, was wholly converted into chyme, while in the other it had experienced but a trifling change. This experiment teaches, not that any exercise, but,—what we need not kill dogs to learn,—that severe and fatiguing exertion, by wasting the bodily vigor, necessarily impairs the power of digestion. Still, gentle exercise in the fresh air, and more especially that to which we have become habitua- FOOD INTO CHYME. 49 ted, has appeared to me rather to favor chymifica- tion than otherwise; and such Dr. Beaumont found to be the case in his subject. Let me here remark that the terms gentle and severe as applied to exercise, are to be understood in relation to the habits and strength of the indi- vidual, for an exertion which would occasion only healthful excitement in one instance, might in another, be productive of painful exhaustion. The vigorous laborer goes to hard work immediately after a hearty meal, and generally experiences no inconvenience in consequence; but should one whose habits are sedentary, or whose body is more feeble, do the same, he would probably have to endure all the sufferings of difficult and imperfect chymification. Sleep and the horizontal posture generally retard the formation of chyme. Dr. Beaumont learnt from his experiments, that sleep or rest in a recum- bent position, reduced the temperature of the stom- ach from its natural standard, which is most favorable to chymification. But I must leave the further consideration of the causes influencing the function of the stomach until I come to treat of the disorders of digestion. 5* 50 FORMER HYPOTHESES CHAPTER V. FUNCTION OF THE STOMACH CONCLUDED. Former hypotheses of chymification, or the con- version of the food into chyme.—To account for the remarkable transformation of the aliment in the stomach,' a variety of hypotheses have at different periods been promulgated, whose absurdity can only find an excuse in the obscureness of their subject. Thus at one time it was ascribed to a putrefaction or rotting of the food, under the favor- ing influence of air, moisture and the high tempe- rature to which it is subjected in the stomach. But healthy chyme emits no putrid odor, and, as I shall presently show, aliments, instead of cor- rupting, are, even when in a putrid state, speedily restored to sweetness by the gastric fluids. Ano- thor hypothesis referred it to fermentation, to excite which a leaven or ferment was imagined constantly to exist. But there is no analogy between the products of digestion and fermentation, and it is now known that the healthful influence of the stomach is to prevent chemical fermentation, and that this process is always unnatural and indicative of imperfect digestion. OF CHYMIFICATION. 51 The sect of mechanical philosophers, who at one period were disposed to refer all the phenom- ena of life to the principles of their own sciences, fancied that the walls of the stomach, operating like millstones, ground down the food into the semifluid pulpy mass called chyme; and hence many of them assumed for this organ a most in- credible muscular power. Pitcairn, for example, computed its contractible force to be equal to a hundred and seventeen thousand pounds, and which he supposed to be aided by an equally powerful pressure derived from the surrounding muscles. Such are the absurdities of philosophers who, blinded by prejudice, model their facts to correspond with their theories. As previously stated, the food is broken down and triturated, in the dense muscular stomachs of many birds, but the human stomach is of quite a different char- acter, being soft and membraneous, and wholly , inadequate to any powerful mechanical action. The best modern physiologists estimate its force of contraction as equal only to a few ounces. Be- side, the food undergoes a positive change of properties, which simple trituration with moisture could not produce. The extremely ridiculous hypothesis ^as even been advanced, that chymification is brought about by the agency of living animals—that a host of small worms, created for this special purpose, immediately on the entrance of the aliment into 52 FUNCTION OF THE STOMACH. the stomach, seize upon it, and greedily tear it in pieces. Modern theory of the function of the stomach.— The opinion now commonly admitted is, that the stomach, in addition to its mucous secretion, pre- pares a peculiar fluid, called the gastric juice, which being powerfully solvent, is mainly instrumental in the formation of chyme. Still, eminent physi- ologists are not wanting, and among them may be mentioned M. Chaussier and Montegre of France, who, on the strength of their experiments and observations, deny the existence of such a specific fluid, regarding that which is so considered, as merely a combination of the saliva with the ordi- nary mucus of the stomach, mouth and oesopha- gus. To be sure, in the human stomach, no separate glands have been discovered for furnish- ing such a secretion; nevertheless I think the evidence is almost conclusive that a distinct and actively solvent liquid does exude from the lining membrane of this organ, and to which chymifica- tion is principally referrible. That it is of itself,— I mean independently of any mechanical aid from the walls of the stomach,—equal to the solution of the food, has been sufficiently established by expe- riment. / Spallanzani enclosed various sorts of aliment in hollow, perforated metallic spheres, and forced them into the stomachs of different animals, and under such circumstances, exempt from any me- chanical influence, they were after a time, varying THE GASTRIC LIQUOR. 53 according to their nature, found to be dissolved. This experimentalist having himself swallowed a perforated tube containing beef, and ejected it in four hours after by vomiting, found the beef soft- ened and partly wasted. The same experiments were repeated by Dr. Stephens, upon a man who had been in the custom of swallowing stones, and with analagous results ; the silver perforated balls employed, being passed in about forty hours, completely vacated of the substances which had been enclosed in them. Dr. Beaumont, whose opportunities for judging on this subject, have at least never been surpassed, asserts that the fluid under consideration is poured out by vessels distinct from those which prepare the mucus;—that it is only discharged under the stimulus of food, or some other substance, to the gastric mucous membrane;—that it dissolves the aliment, changes its properties, and converts it into chyme; its action, however, being facilitated by the warmth and motions of the stomach. Description of the gastric liquor.—As ordinarily procured by experimenters, this substance is ne- cessarily mixed with mucus, and oftentimes with saliva. In the pure state in which Dr. Beaumont was enabled to obtain it, it was a clear and trans- parent fluid, without odor, slightly salt, and per- ceptibly acid to the taste, and was kept for months without manifesting any sensible change. On chemical examination, it was found to contain free muriatic and acetic acid, beside several neutral 54 CHEMICAL PROPERTIES salts and an animal matter. Dr. Prout affirms that it always contains muriatic acid. But, as is true of all the other animal fluids, the results of its analysis have varied in the hands of different chemists. Perhaps it undergoes modifications to suit the nature of the food on which it is to act;— thus it has been asserted to differ in the flesh, and vegetable eating animals. Different conditions of the stomach, or of the general system, may likewise influence its character. The chemical constitution of this fluid, so far at least as we are yet acquainted with it, will by no means explain its powerful agency in digestion. Its free muriatic acid would appear to be its most active solvent ingredient, yet, being in but slight excess, we should conclude it quite inadequate to the effects accomplished. Chemical properties of the gastric liquor.—The solvent power of this liquid, to which I have already alluded, is very energetic in man, but still more so in many of the inferior animals. It ap- pears generally to hold an inverse ratio to the muscular strength of the stomach, being greatest in those animals who have thin membraneous sto- machs, in which its agency is of course most needed. Even the soft, semi-solid stomachs in many of the moluscous or gelatinous animals, known under the common name of sun-fish, are capable of digesting hard and rough substances, as for example, a small prickly fish, on which some species of them feed. OF THE GASTRIC LTQUOR. 55 Some years since, an account was published of a seaman, who, during ten years, had been in the occasional practice of swallowing claspknives to amuse his companions. At first but trifling incon- venience ensued; but in the end, the stomach became so weakened as to be incapable of trans- mitting these bodies to the intestines. The man at length died in an English hospital, and on ex- amination, there were found in his stomach between thirty and forty fragments or portions of blades, knife-springs, and handles, greatly corroded and much reduced in size by the solvent power of the gastric juice. The handles being, for the principal part, of horn, were almost wholly dissolved.* In the stomach of the dog, common bones, and even ivory undergo solution. Gastric juice has the property of coagulating milk, and albuminous fluids generally. Milk, uniformly becomes solid in the stomach previous to its conversion into chyme, hence when infants vomit this fluid, it is always found to be curdled. The same property is in like manner possessed by the dead stomach; the substance termed rennet, employed to coagulate the milk for making cheese, is a simple infusion of the digestive stomach of the calf. In a trial made by Dr. Fordyce, six or seven grains of the inner coat of the stomach infused in water, afforded a liquor which coagulated more than a hundred ounces of milk. It is probable # Medico-Chirurg. Trans, vol. 12th, part 1st. 56 THE GASTRIC LIQUOR. that most, if not all albuminous substances, are coagulated before being digested. This remarkable fluid, is, moreover, antiseptic, having the quality both of resisting and correcting putrefaction. The northern savage often eats his fish in a highly putrid state; and certain meats, as mutton and venison, are not unfrequently eaten even in civilized life, when the putrefactive process has commenced in them. Many of the inferior animals, as the dog for ex- ample, are well known often to feed on flesh far advanced in decomposition. The raven and vul- ture, as also many other birds of prey, revel and fatten on the most putrid animal substances, being attracted often from great distances by their efflu- via. Now it appears from experiment, that food in this condition is quickly restored to sweetness in the stomach. Dr. Fordyce proved that the gastric juice of a dog soon sweetened the most putrid meat that he could be made to swallow; and Spallanzani showed that the same fluid from the crow and dog, will preserve veal and mutton for thirty-seven days in winter, whereas immersed in water, they become fetid by the seventh day, and are perfectly putrid by the thirtieth. Some articles which otherwise introduced into the system, are highly poisonous, when taken into the stomach are decomposed or resolved into their elementary principles by the agency, as is believed, of the gastric liquor, and their noxious properties ACTION OF THE GASTRIC JUICE. 57 thus destroyed. Such is said to be the case in re- gard to the poison of the rattlesnake and viper. Action of the gastric juice on alimentary sub- stuHccs out of the stomach.—Spallanzani found that masticated meat put in a vial with a certain proportion of the gastric liquor, maintained at the natural temperature of the body, and subjected to gentle agitation, in a few hours was dissolved and presented the appearance of chyme. Dr. Beaumont also made a number of experiments on this subject, and with results analogous to those of Spallanzani. lie found it highly essential to the process, that the heat of the mass experimented upon, be kept at about 99° or 100° of Fahrenheit, ascertained to be the usual temperature of the stomach during di- gestion, and also that it was much facilitated by gentle agitation, which removed the external layer of chyme, thus affording the gastric juice more ready access to the undissolved parts beneath. The solution, however, goes on with greater rapid- ity, and probably, perfection, in the stomach; being favored by the regular motions of the organ, and the fresh supplies of its secretion which are brought to act on the undissolved aliment as that which has undergone its destined change is removed. It ' may be, too, as before suggested, that difference in the nature of the diet calls for some modification of character in the digestive fluid. Though the solution of alimentary matters out of the body by the agency of the gastric juice cannot be questioned, yet many physiologists deny 6 58 GASTRIC JUICE ACTS NOT ON LIVING MATTER. it to be chymification, believing the peculiar vital action of the stomach essential to this process. Haller, Richerand and others have thought that bile was requisite to the formation of chyme; and it is true that this fluid does sometimes enter the stomach, and particularly when fatty and oily food is taken, and probably assists its digestion. The duct, however, which conveys the bile from the liver, has been tied in animals, and still chymifica- tion has gone on, and with apparent perfection. The gastric juice does not act on living matter.— Observation instructs us that living matter will withstand the influence of many agents which speedily corrode and destroy it after its vital prin- ciple has departed. It is well known that worms live in the stomach of man, and of numerous other animals; and that reptiles and insects inadvertently swallowed, have existed here for some days. Dr. Good cites an instance of a water lizard being found alive in the stomach, two days after it had been swallowed. " Frogs and serpents," says he, "have for a longer period of time been equally able to resist the action of the stomach; leeches swallowed unintentionally, in a draught of muddy water, have thriven and grown to an enormous size; the eggs and larvae of various insects, and especially of the musca cibaria, and even of the spider, have been hatched or perfected in the stomach or intestines, and the kernels of plum and cherry stones have germinated there » * * Study of Medicine. ITS SOLVENT POWER ON DIFFERENT SUBSTANCES. 59 It is the principle of life that preserves the stomach itself from destruction by its own secretion. Some physiologists assert that parts of this organ have actually been dissolved by the gastric juice when subjected to its action after death. Mr. John Hunter, I believe, first called attention to this sub- ject ; and conceived it necessary to such a result, that the individual should die suddenly in the midst of full health, and when the gastric liquor under the stimulus of food, had been recently poured out. Subjected to such conditions, he imagined that this secretion would act on the stomach as on any other dead animal matter. But it may at least admit of a question whether the perforations and partial solutions which have been occasionally witnessed in the stomachs of man and some of the inferior animals in cases of their sudden death, and referred to the corrosive action of the gastric fluid, might not in reality have originated prior to dissolution and from some other cause. The facts and observations in connexion with this subject are as yet too limited to warrant any confident conclusion in regard to it. So!rent power of the gastric liquor on different substances.—Different alimentary substances are dissolved with greater or less facility under the in- fluence of this agent, and which is far from being determined in every instance by their mechanical texture or particular physical properties. " While" —to use the language of another—" it acts upon the densest membrane; while it speedily dissolves 60 CONTRACTIONS OF THE STOMACH. bone itself, it produces not the slightest effect upon many substances of the most delicate texture; the skins of fruit, for example, and even the finest fibres of flax and cotton are not in the smallest de- gree affected by it. This selection of substances exactly resembles the operation of chemical affin- ity, and is decidedly contrary to what would be the effect of mechanical agency."* It operates with difficulty on most crude vegetable matters, and in a more particular manner on their stalks and leaves. Farinaceous vegetable mailer, and lean flesh, as a general rule, appear to be most readily soluble in it. Influence of the muscular contractions of the stomach in forwarding chymification.—Under the influence of the longitudinal, and circular or trans- verse contractions of the stomach, assisted probably by the play of the diaphragm and abdominal mus- cles during respiration, the alimentary matters are subjected to an oscillatory motion,—are gently ag- itated and compressed, and their admixture with the gastric juice, and consequently their solution, thus facilitated. Such is in correspondence with what happens in all chemical solutions, they being uni- formly expedited by agitation, through which the dissolvent is brought into more intimate and exten- sive contact with the soluble matter. The muscular contractions of the stomach are evidently affected by the qualities of the food; thus * Library of Useful Knowledge. Article,-Animal Physiol, UNION OF THE GASTRIC FLUID WITH FOOD. 61 some sorts call forth rapid, and others more tardy motions; and sometimes the natural order of its action appears to become inverted, as in vomiting. Manner in v)hich the gastric fluid unites with the food.—Many physiologists teach that the action of the gastric liquor is confined to the superficies of the food, alternate layers of it, as they are dissol- ved, being separated or rolled off from the rest, and carried to the pylorus by the motions of the stomach, and consequently that digestion goes on only at or near its mucous surface. Dr. Beaumont, however, observed in St. Martin's stomach, that the secretion gradually insinuated itself into, and became com- mingled with the whole alimentary mass, and that solution was progressing simultaneously through- out it. He remarked, too, in opposition to the statement of several physiologists, that chymification begins immediately on the entrance of the food into the stomach. Is chymification limited to any particular portion of the stomach 7—Here, again, physiologists are at issue, some believing that it is accomplished espe- cially in the left or cardiac extremity, others in the right or pyloric, and many that the alimental mass circulates promiscuously about the whole cavity. Sir Everard Home described a sort of hour-glass contraction of the circular fibres of the stomach, during digestion, separating the greater from the less extremity, the purpose of which, was thought to retain the food in the former situation until it should be transformed into chyme. Many 6* 62 PASSAGE OF THE ALIMENT have been skeptical in regard to this appearance, but Mr. Mayo asserts that he has seen it on several occasions in instances where death has happened suddenly while digestion was going on, and it is his opinion that the food thus retained in the great end of the organ is slowly dissolved, the solution taking place upon the surface, " and in proportion as it proceeds, the dissolved part is rolled off the rest by the peristaltic action of the fibres of the stomach, and carried to the pyloric portion."* But have we a right to conclude that a mode of contraction occasionally witnessed in the organ after death, necessarily represents its natural and healthy action? Passage of the aliment into the intestines.— The food being converted into chyme, the pyloric orifice which was before shut, now relaxes under its impression, and allows it a ready passage into the intestines. It is from the circumstance of its guarding the entrance of the bowels that this outlet has received its name of pylorus, which corres- ponds with the Greek word meaning a guard or doorkeeper. Beside the pylorus, we remark many other instances in the animal body of organs en- dowed with a sort of selecting tact, or, if I may thus term it, organic instinct, under whose super- intendence, when in health, they admit only such substances as are appropriate to their wants, reject- ing, or attempting to reject all others. Thus * Outlines of Physiology, p. 132. INTO THE INTESTINES. 63 atmospheric air readily passes into the windpipe, but when irritating and noxious effluvia are com- bined with it, the opening into this passage con- tracts against them, and if perchance they gain an entrance, a convulsive cough immediately ensues for their expulsion. Though, however, the pylorus tends to close against other substances than chyme, insomuch that food which is not digested will oftentimes be returned by the oesophagus and mouth, rather than be permitted to enter the intestines, still it does in many instances give way to them.—Thus the stones and skins of fruit, seeds, greens, and various undigested substances, are frequently passed by the bowels ;* the pylorus, yielding as it were to the urgency of their solicitations, and the necessity of the case—for they could not remain in the stomach without endangering its welfare—at length withdraws it resistance. Broussais suggests that these crude matters clear the pyloric strait by aid of others more advanced in digestion, or in other words by stealing along with the chyme. In many morbid conditions of the stomach, undi- gested substances are constantly passing into the intestines, but here the natural relations are changed. * This is of material importance in the extension of the vegetable kingdom, since it is thus that birds are enabled to transfer the seeds of plants to coral islands and various distant situations, their germina- tion manytimes being even facilitated by the maceration to which they had been subjected in passing through the alimentary canal. 64 DESCRIPTION OF THE CHAPTER VI. CHYLIFICATION, OR SECOND DIGESTION. Chylification consists in the transformation of the chyme into a peculiar milky substance denomi- nated chyle; and is the next in the series of changes which the aliment undergoes preparatory to its conversion into blood, and assimilation with the living structures. Owing to the difficulty of observing it, this process has been less studied, and less, consequently, is known about it, than of stomachic digestion. The chyme, on its entrance into the small intes- tine, under the influence of the secretions of the liver and pancreas, soon begins to manifest new characters. Description of the small intestine.—This division of the alimentary canal is included between the stomach and large intestine. Its length is generally stated to be about four times that of the body, though this proportion is far from being constant. In its diameter, it insensibly diminishes from its commencement at the outlet of the stomach till it communicates with the great intestine. Its struc- SMALL INTESTINE. 65 ture is essentially the same as that of the stomach, having like it, a serous, muscular and mucous coat. Its muscular coat has a longitudinal and transverse layer of fibres, and appears to differ from the cor- responding one in the stomach only in being somewhat weaker. The mucous or inner mem- brane is more villous than in the stomach, and is furnished with large and numerous transverse folds or plaits, as they appear, called valvules. conniventes, or winking valves, which serve to retard the passage of the chyle, and to increase the surface from which, as I shall presently show, it is to be absorbed to get into the circulation. The mucous secretions are here very abundant. Though the small intestine is one continuous tube, yet anatomists describe it under three divis- ions, called duodenum, jejunum and ileum. The duodenum is the superior, communicating directly with the stomach, receiving the chyme and con- tributing to its conversion into chyle. Its name is derived from the Latin word duodeni, meaning twelve, because it was considered to be about twelve finger-breadths in length. About twelve inches are now commonly allowed to it. The diameter is here greater, and the muscular coat thicker and stronger than in either of the other • divisions. Different from them, too, it has but little freedom of motion, being closely secured to the back part of the abdomen by its peritoneal or outer coat, two portions of which, meeting behind, are extended from it for a short space in the form of a 66 STRUCTURE OF THE LIVER. double layer, and fastened to the spine.—In the direction from right to left it makes an obvious curvature, serving to delay the passage of the chyme until it has experienced the necessary influ- ence here to be wrought upon it.—It is largely furnished with nerves and bloodvessels, marking the high importance of its function. The duodenum is by many physiologists looked upon as a lesser or secondary stomach, and it has even been imagined, though without adequate evidence, that, like this latter organ, it secretes a peculiar fluid subservient to its office. Into the posterior part of this division, a little above its middle, the ducts from the two large glands in the immediate vicinity, viz. the liver and pancreas, enter,—sometimes separately, sometimes in union—and discharge their secretions. The next division, comprehending two fifths of the small intestine, is the jejunum, so called be- cause it is commonly found empty, jejunus being the Latin word for fasting. All the remainder is called ileum or ileon, from a Greek word siXeu— eiteo—meaning to turn about, and expressive of its numerous turnings, or convolutions. These two latter divisions are allowed a large extent of • .motion, and hence are called free or floating. They* have a thinner muscular coat, a somewhat smaller diameter, and are generally stated to possess less irritability than the duodenum. Structure of the liver.—This is the largest gland in the body. It is situated principally on the right STRUCTURE OF THE LIVER. 67 side, below the diaphragm,—to the inferior surface of which it is united, and thus in a measure sus- tained in its position—and above the stomach, with which it is also connected. Its right extremity is more thick and bulky than its left. Its superior and anterior surface is regularly smooth and con- vex ; its posterior and inferior, irregularly concave. It has three lobes or divisions, formed by deep fissures in the organ—viz. the right or great lobe,— the left, considerably smaller and extending some- what into the left side—and the little lobe, or lobe of Spigelius as it is called, situated posteriorly. In the concave, or hinder surface of the great right division, is a slight excavation in which is lodged a small oblong membraneous bag, called the gall-bladder. The liver varies considerably in regard to its size in different individuals; on a general average, however, its weight in the adult may be stated at about four pounds. In some diseased conditions, it becomes enormously enlarged. Its color is a dull red, its structure granulous, and its consistence moderately soft. From each of the fleshy granules composing this organ, seem to proceed—though their begin- nings are too minute to be sensible—little tubes, which uniting together with an apparent irregular- ity, finally all terminate in a single one, of a relatively large size, called the hepatic duct. This, issuing from the under surface of the liver, directs its course toward the duodenum, but before reach- 68 FUNCTION OF THE LIVER. ing it, is met, at nearly a right angle, by still another from the gall-bladder, called the cystic duct,—from a Greek word, meaning a bladder,— which, uniting with it, they form a single pipe, called the common duct, or in technical language, ductus communis choledochus. This proceeds directly to the duodenum, and perforating its two outer coats, passes a little way, between the mus- cular and mucous, and then penetrating the latter, opens into the cavity of the intestine about two inches from the pylorus. Or perhaps I may render this arrangement more intelligible by saying that the hepatic duct in its course from the liver to the intestines, reflects from itself at nearly a right angle, another, or the cystic, which having pro- ceeded a short distance, suddenly swells into the gall-bladder. It will be seen here that the bile, to arrive at the gall-bladder, must turn at almost a right angle, and ascend against its own gravity. Function of the liver.—The liver prepares the peculiar fluid we term bile. This is a viscid, unctuous, slightly bitter liquid, varying in consist- ence, and exhibiting, sometimes a yellowish brown, at others a light yellow, and again a green color. In its chemical constitution it is the most complex of all the animal fluids. A portion of the bile, as it passes from the liver, commonly takes its course to the gall-bladder, where it is retained as in a reservoir, and where it experiences new modifications in its properties, which are probably of importance in the economy FUNCTION OF THE LIVER. 69 of digestion. Bile having remained a certain time in the gall-bladder, and its watery parts being diminished by absorption, becomes thicker, and more unctuous and bitter, than when first secreted, and assumes a decided green hue. It is here called gall, and owing to its greater concentration, is thought to be a more active stimulus to the intes- tines than bile direct from the liver. During chylification,—and, it may be, through the whole process of digestion,—the secretion of bile is augmented, and a draft is also made on that reserved in the gall-bladder. This fluid, beside its probable use in transforming chyme into chyle, has also an important one in refer- once to the feces; its combination with them, dimin- ishing their cohesion, giving a smooth polish to their surface, and rendering them more stimulating to the large intestine, thus materially facilitating their discharge. If perchance this secretion is deficient, the feces usually become dry, rough, and hard to be evacuated; assume a light color, or that of dry clay, and the bowels suffer from constipa- tion. But other important uses, beside those in direct reference to digestion, have been ascribed to the liver. Some physiologists believe that like the lungs,—on the common theory of respiration,—it purifies the blood of its carbonaceous matter; the bile containing a large proportion of carbon in many of its principles, which are excreted with the feces, as the resinous, fatty matter, &c. : that it 70 FUNCTION OF THE LTVEK. is, therefore, a repetition of the breathing organs, or in other words, that its function is supplement- ary to theirs; serving to carry off, any excess of carbon which the lungs may have left in the blood; —by respiration, it being separated in an ceriform, by the hepatic function in a more solid state. There are several facts which, to say the least, give plausibility to such an opinion. Thus com- parative anatomy teaches that the developement of the liver in different animals is ordinarily in an inverse ratio to that of the respiratory organs. Tiedemann found, too, in those warm blooded ani- mals, who dive, or burrow,—as the otter, marmot and field-mouse,—and who are thus often deprived, either wholly or partially of air, that the liver was relatively much larger than in such as live more uniformly on the surface of the ground. Before birth, and of course previously to respi- ration, the relative magnitude of the liver is very remarkable, and the secretion of bile considerable. But afterwards, the function of the lungs having become established, the proportional bulk of the liver gradually lessens, and at adult life, when the chest has acquired its greatest developement, this organ,—though to be sure still large—has its least relative size. It may furthermore be suggested that warm cli- mates—in which the hepatic function is in greatest activity, and bilious complaints most prevalent — are most favorable to the health of the lungs. Now may it not be that this increased activity of the PANCREAS. 71 liver, in union with that of the skin, serves in a measure to lighten the labor of the lungs? It has been remarked in diseases of the heart, which are known greatly to embarrass the breathing, that the liver becomes enlarged; and also in what are called blue children, who are born with some imperfection of the heart or its great vessels, that the liver con- tinues to preserve its early state of disproportion. Be this theory, however, true or false, there are few reflecting physiologists who do not suspect that the liver has some other purpose in the econ- omy, beside its subservience to digestion. The high importance of biliary organs is declared by the great constancy with which they are found in the different animal organizations. Pancreas.—The pancreas, or sweetbread, as it is called in the calf, is an oblong gland, of a light, or yellowish white color, weighing in the adult from four to six ounces, situated behind the stomach, and transversely in relation to the spine. In color and structure it nearly resembles the salival glands. A duct issues from it and enters the duodenum in company with, or close to that which conveys the bile. The chemical nature of the secretion of this gland,—owing to the difficulty of procuring it apart from the bile and fluids of the duodenum—has been but little studied. Collected, however, as it passes by drops into the intestine, its sensible prop- erties are found closely to resemble those of the saliva. 72 SPLEEN. The pancreatic fluid, called into the duodenum during digestion, unites with that of the liver, and concurs with it in its action on the chyme. Spleen.—The spleen or milt, though we have no certain knowledge of its uses, by many physiologists has been associated with the digestive organs, and regarded as directly or indirectly contributory to their functions; and this opinion would seem to be favored by its situation and anatomical connexions. It is an oblong, flattened, oval viscus, of a deep color—which it owes to the large amount of dark red blood it contains—of a very brittle texture, and principally composed of blood vessels. It is seated in the left side, behind and adhering to the great extremity of the stomach. Its average weight in an adult is from seven to nine ounces; but it varies considerably in size, and oftentimes even in shape and position, in different individuals. Some eminent physiologists of the present day believe the spleen to be subservient to the function of the liver,—or that it accomplishes some change in the blood preparatory to the secretion of bile. It is well known, however, that bile can be formed when this organ is absent. The spleen has for ages afforded a most fruitful theme of fanciful hypotheses. Thus mel- ancholy or low spirits were once referred to it, and hence acquired, and still retain the name of spleen. The ancient Greek physicians fancied that the blood was formed in the liver by the four prin- cipal humours of the body, at their time believed to SPLEEN. 73 exist. These were called yellow bile,—blood, or the portion imparting the red color,—phlegma, or pale watery humour, meaning probably the serum,— and melancholia, constructed from the Greek words I^Xas, melas, meaning black, and x0*-^ cholee, bile, this was a dark thick fluid. Here, by the by, we trace the origin, to a false medical theory, of the common term melancholy. Now these four essen- tial humours were supposed to be conveyed to the liver, and there, as it were in a laboratory, united to- gether to form blood. But since, as might be expect- ed, they would not always be in the exact proportions necessary to form this fluid, any redundance of them must be carried away, subserving, according to its nature, some useful purpose, or exciting dis- turbance in the economy. Thus the secretion of the liver was viewed but as the excess of the simple humour called yellow bile, and for which the gall-bladder was the appropriate receptacle. When the melancholia or black bile was too abun- dant, its superfluity was carried to the spleen, which was thought to be its peculiar reservoir; probably from the large quantity of dark grumous blood which this viscus is always found to contain. Some, however, imagined that the spleen, instead of being a simple recipient, prepared or concocted the melancholia, but all agreed that here was its seat. Now this particular humour, perhaps owing to its dark and gloomy aspect, was by the ancient physicians, who were all humouralists-^-WmX is, held diseases to originate in the fluids, or humours 7# 74 SPLEEN. of the body—viewed as a grievous disturber both of our moral and physical tranquillity—and to its su- perabundance were referred irritability, low spirits, and even hypochondriacism, which affections were hence generally denominated spleen. I may here remark that the ancient division of temperaments, and which is still retained, was based on these four humours, and from them derived their names. The sanguine temperament was attributed to the prevalence of the red humour, now called red globules of the blood;—the phleg- matic, to that of the phlegma, or pale Avatery humour,—the choleric, from the Greek word mean- ing bile, to that of the yellow bile, or proper secretion of the liver,—and the melancholic, to that of the melancholia or black bile. The spleen, because it is seated in the side, and tickling the sides makes a man laugh, has even been regarded as the seat of laughter, and the great propensity to it manifested in some persons has been ascribed to an enlargement of this viscus. Sir Charles Bell facetiously remarks that, " we have authority for the excision of the spleen from those who are otherwise incurable in their propen- sity to laughter!" It has, however, been very gravely objected to this opinion, that laughing is produced by tickling the right as well as the left side. But, seriously, we know absolutely noth- ing about its function. Like some other parts in the animal system, it has the texture of glands, PHENOMENA OCCURRING IN THE DUODENUM. 75 and their great vascularity, but differs from them in possessing no excretory ducts. The fact that this organ has often been extirpated in the inferior animals,—as in dogs for example— and occasionally even in man, and without subse- quent injury to health, proves that whatever its function may be, it is not essentially necessary to existence. Phenomena which take place in the duodenum.— On the entrance of the chyme into the duodenum, it becomes mixed with the mucus formed there, and also with the bile, and secretion of the pan- creas. The two latter fluids, invited by the stim- ulus of the chyme, immediately begin to pass, though slowly, from their ducts into the intestine, blending gradually with its contents. Experiments on living animals have shown that a drop of bile appears at the orifice of the common duct, and diffuses itself over the neighboring surface about twice in a minute, and that the passage of the pancreatic liquid is still slower. It is not long, however, before the chyme acquires the color and bitterness of the bile. Soon after the union referred to, the mass sepa- rates into two distinct portions, viz. a milky, tena- cious, and slightly coagulable fluid, called chyle, and which is to be absorbed into the system for its support, and a yellowish pulpy mass, or the excre- mentitious part, which, after experiencing some further changes, is to be dismissed from the system. 76 PHENOMENA OCCURRING IN THE DUODENUM. This decomposition or separation of the chyme, is, by the greater number of physiologists, at- tributed to the agency of the bile and pancreatic fluid, whose union with it is supposed to effect a sort of chemical precipitation of the impurities of the aliment. The subject however is still obscure, and some recent researches, especially those of Tiedemann and Gmelin, have tended to cast con- siderable doubt over the uses of these secretions in chylification. The function of the duodenum is performed in less time, and probably with less labor, or at any rate it makes a less draft on the powers of the system than that of the stomach. And like the function of this latter organ, it must also be influ- enced both in regard to its celerity and perfection, by a variety of incidental circumstances. Chylification has a very close dependence on chymification. Thus if the latter is not accom- plished, the food generally passes with but little alteration through the whole alimentary canal. Nevertheless the fluids of the intestines do display some solvent properties in relation to the food, when sufficient time is allowed for their action. Hence articles which have escaped the influence of the stomach will sometimes undergo, in their passage through the intestines,—if it be slow,—a more or less obvious solution, and change of char- acter. That solution continues to be effected in the intestines of animals which feed on herbage, is sufficiently evident. PASSAGE OF THE CHYLE. fT CHAPTER VII. PASSAGE OF THE CHYLE AND REFUSE PORTION OF THE FOOD THROUGH THE SMALL INTESTINE ;--ABSORPTION OF THE FORMER, AND ITS TRANSMISSION INTO THE CIRCULATION;--COURSE OF THE LATTER THROUGH THE GREAT INTESTINE, AND ITS DISMISSAL FROM THE BODY.—INFLUENCE OF FOOD IN THE STOMACH UPON THE GENERAL SYSTEM.--PASSAGE OF FLUIDS FROM THE STOMACH. The nutritious and excrementitious elements of the food, being separated from each other in the duo- denum, are impelled along the small intestine by its peristaltic or vermicular motion, resulting from the contraction of its circular and longitudinal muscular fibres, assisted probably by the agitation imparted to the bowels, by respiration, and the various kinds of exercise. The folds of the mucous membrane, and the frequent curvatures of the intestine, which oblige its contents often to pass counter to their own gravity, guard against the too rapid passage of the chyle, and thus suffi- cient time is allowed for its absorption. A certain amount of air is always found in the stomach and 78 LACTEAL ABSORBENTS. bowels, and seems absolutely essential to their healthy action. The chyle, keeping in contact with, or adhering to the mucous membrane, is absorbed from it by a system of vessels called lacteals, which will here demand a brief description. Lacteal absorbents.—The lacteals, so named from the Latin word lac, meaning milk,—because they convey a whitish, or milky fluid,—arise, probably,— their origin not being obvious to the senses,—from numerous minute pores or capillary orifices in the villi of the mucous membrane, and absorbing the nutritious materials to convey them into the circu- lation, bear to the animal a relation somewhat analogous to that of roots to the vegetable. Thus in the plant, nourishment is absorbed from the soil by the fibrils of its root,—in the animal it is absorbed from the mucous membrane of the intes- tines by the fibrils, if they may be so termed, of the lacteal apparatus. The lacteals originate especially in the small intestine, and pass in great numbers between the two layers of what is termed the mesentery ; that is, a posterior extension of the outer or peritoneal coat, in the form of a double membrane, enclosing more or less fat, tying the bowels loosely to the spine. In their course these vessels frequently open into and intersect each other, though without changing their diameter, and at length enter and are lost in what are called the mesenteric, or lacteal ganglions, or glands. These are small LACTEAL ABSORBENTS. 79 lenticular bodies,—their shape being generally compared to that of a flattened olive,—scattered about, numerously and irregularly, in the fat between the two layers of the mesentery. Some are half an inch or more in length, while others are too minute to be readily distinguished. Their developement is greater in early than in adult life, and in the former period they are often found mor- bidly enlarged. They exhibit a pale red, or rose color, which is. rendered lighter when they are filled with chyle. Their color, however, is sub- ject to variations, which may often be owing to diseased conditions of them. They are invested by a dense and externally shining membrane, and seem to possess a high degree of vitality. The intimate construction of these bodies is not clearly comprehended. Some imagine that they are only the lacteals coiled up in this particular form, and that therefore the chyle winds through them without leaving its vessels, while others suppose that this fluid on entering them, becomes extravasated, and is then again taken up by absorption. Be this as it may, all the chyle is obliged to pass through them, and hence it is reasonable to infer that some additional vital change is here wrought upon it preparatory to its reception into the blood. The sponglets, as they are termed, that is, minute, oblong, oval spongy bodies situated on the fibrils of the roots of plants, may not unlikely subserve an analogous use in the economyof the vegetable, that the mesenteric gangli- 80 LACTEAL ABSORBENTS. ons do in that of the animal, and which, if true, fur- nishes another circumstance in favor of the analogy between the lacteal absorbents and vegetable roots. On the opposite side of these ganglions, issue little tubes, or lacteal vessels, corresponding with those which were seen to enter them, still carrying forward the chyle. These soon unite to form larger ones, all finally terminating in one still more capacious, being about the size of a goosequill, called the thoracic duct. This commences in the cavity of the abdomen, and passing through the diaphragm, ascends along the spine to the apex of the thorax, where it opens into one of the large veins, at a little distance from the heart. I have thus traced the chyle into the circulation, where it is no longer distinguishable from the blood. In the thoracic duct, the chyle meets and be- comes mixed with a transparent, watery fluid called lymph, brought to it by a set of vessels denominated, from the matter they convey, lym- phatics. These being found in almost all parts of the body, and supposed, at least by the greater number of physiologists, to be subservient to the function of absorption, which must take place throughout the system, have been named general absorbents, in contradistinction to those described, which arise from the intestines only, and seem destined to the absorption of nutrimental matters. These two classes of absorbents manifest in many respects a near resemblance to each other. DESCRIPTION OF CHYLE. 81 Thus, like the lacteals, the lymphatics previously to arriving at the thoracic duct, enter into, and emerge from little, roundish, fleshy bodies, much like those through which the chyle passes, called lymphatic, or absorbent glands or ganglions. Chyle in the thoracic duct then necessarily differs from that in the duodenum. It is in the former situation only,—where being separated entirely from the matters in the intestines, and having experienced the influence of the lacteal glands, and become further modified by its union with the lymph,—that the chyle is perfected, and approximating most closely to the nature of blood, is ready to be converted into this fluid. It is this chyle which is most commonly subjected to exami- nation, and whose properties therefore I will here briefly describe. Description of chyle.—This fluid drawn from the thoracic duct of animals was observed by Magendie to vary in appearance according as they had, or had not fed on aliments containing oil or fat. In the former case, its color was milkwhite, and white opaque matter rose to its surface. In the latter, it was nearly transparent. That the chyle differs in some measure according to the nature of the food is doubtless true, yet colored substances mixed with the aliments seldom impart any tinge to it. The chyle I am describing is a little heavier than distilled water, having a saltish taste, and slight alkaline properties, which latter not being 8 82 ABSORPTION OF CHYLE. possessed by the chyme, have by some been referred to the bile, a highly alkaline fluid. Its analogy with the blood, into which it is soon to be trans- formed, is very close. Like this fluid, it coagulates soon after being drawn, separating spontaneously into a solid and liquid portion, the former resem- bling the clot of the blood, the latter its serum, or watery part. It has now, too, assumed a faint reddish tint. Like the blood, moreover, it contains minute globules varying in size, though smaller than the red globules of this fluid. Chemists have likewise detected different salts in the chyle, cor- responding with such as are found in the blood. Each successive change experienced by the aliment from its first reception into the body has obvious reference to its final destination, or advances it more nearly to the nature of the vital fluid with which it is ultimately to become iden- tified. Thus the chyle in the duodenum has more of the properties of the blood than the chyme; and that in the thoracic duct still more than that in the duodenum. In short we may say that the food goes on acquiring vital properties until it makes part of the different animal structures. Absorption of the chyle.—Row the chyle is taken up from the mucous membrane, or how its absorp- tion commences, whether by a physical or vital power, is not decided. Some refer it to capillary attraction, which opinion gains some support from the fact that it has been seen passing a short dis- tance into the lacteals, when life, both animal and ABSORPTION OF CHYLE. 83 organic, had entirely ceased. Yet that vitality is concerned in it appears to be evinced by the circumstance that chyle is selected for absorption in preference to other matters not adapted to nutrition. Though, however, the lacteal vessels display a special affinity for chyle, still they do also admit other substances, and such even as are deleterious, or perhaps poisonous to the system. In disease, their discriminating property is often much impaired, and imperfect chyle, and other unsuitable matters may be absorbed to the detri- ment of the system. The lacteal absorbents being furnished with numerous pairs of valves, all opening forward, or toward the point where their contents pass into the circulation, it is plain that the contraction of these vessels necessarily press onward the chyle, when it is once beyond the first pair of valves. The thoracic duct at its termination in the venous sys- tem, is supplied with a valve to guard against the return of its contents, and the intromission of the blood. Having entered the blood, the chyle must be subjected to another important influence before its sanguification is completed. Entering the venous system near the heart, it is soon carried to the right side of this organ, from Avhence—having been agitated and more perfectly mingled with the blood —it is transmitted to the lungs, and there acted upon by the vital air, it receives its last finish, and is now fitted to convey life and health to every 84 PASSAGE OF THE RESIDUAL MATTER, part of the system. How important therefore is pure air to the perfection of nutrition may now be readily inferred. Passage of the residual matter, and its dismis- sal from the body.—That portion of the food which is not absorbed into the circulation is slowly trans- mitted through a sort of valve, called the coecal valve, separating the large from the small intes- tine, into the ccecum, or first portion of the former. This is a swell or enlargement in the alimentary canal marking a new division and a new function. On entering here, the contents of the bowels quickly assume the peculiar characters of feces. The remaining divisions of the great intestine are the colon and rectum. The diameter of the large, is much greater than that of the small intes- tine, while its length is considerably less. The colon is by far the most extensive portion. The rectum constitutes the inferior division and termi- nates in the outlet of the alimentary canal. The general structure of the large intestine cor- responds with that of the small. Its muscular coat, however, is more powerful, surpassing in strength even that of the stomach, and its internal or mucous membrane is destitute of transverse folds, or valvulce conniventes. The colon exhibits circular contractions at reg- ular intervals, as though bands were tied round it, and is thus divided into a number of cells. These are susceptible of great distension, and seem de- signed as places of deposit. Indeed the whole AND ITS DISMISSAL FROM THE BODY. 85 colon must be regarded in the light of a reservoir for the foscal matters. Few, if any, lacteal absorbents arise from this division of the alimentary canal, and in healthy digestion no chyle is found beyond the coecal valve. General absorbents however exist here, taking up the more fluid parts of the feces, and probably extracting from them any remaining nu- tritious particles. That some nutriment may be absorbed from the large intestine is evident from the fact that persons have been sustained for a time by clysters alone. Sir Astley Cooper, knew a lady, having a stricture of the oesophagus, to be supported forty-five days by clysters of broth and wine, when she could not swallow even a drop of water. It would appear then that undigested liquid aliment absorbed into the bloodvessels can con- tribute in a degree to nutrition; and it may be that some of the more subtile parts of the food are imbibed from the stomach by general absorbents, to be applied to the purposes of nutrition. The secretions of the large intestines are less abundant than in the small, and hence their con- tents, becoming more consistent, and their passage being delayed by the cellular structure of the colon, are evacuated only periodically, an arrangement highly conducive to comfort. When a certain amount of excrementitious matter has descended to the inferior portion of the large intestine, the brain becomes apprized of it, and consentaneous or cooperating muscular contrac- 8* 86 PASSAGE OF THE RESIDUAL MATTER. tions and relaxations, partly voluntary, and partly involuntary, are excited for its expulsion. The frequency of the dejections will depend on the character and quantity of the food, and on the constitution and habits of the individual. Vegeta- ble, on a general principle, affords a larger proportion of refuse matter than animal food. Thus the foecal discharges of animals which feed on vegetable substances, especially on grass and herbage, are more frequent and abundant than in such as live on flesh. In health, the evacuation ordinarily takes place about once, though sometimes twice, in the twenty-four hours. In some individuals, however, it happens only every other day, and in occasional instances but once in several days. Magendie states that in certain persons, and who enjoy good health, it does not occur oftener than once in ten or twelve days. " A very great differ- ence"—says Dr. Heberden —"is observable in different constitutions in regard to the evacuation by stool. One man never went but once in a month: another had twelve stools every day for thirty years, and afterwards seven in a day, for seven years, and in the mean time did not' fall away, but rather grew fat." * Such cases, how- ever, are but exceptions to the general rule, and in almost all constitutions, it is essential to health that a dejection take place daily, or at furthest every other day. * Commentaries. INFLUENCE OF THE FLOOD IN THE STOMACH. 87 Custom exercises a very marked influence in respect to the regularity of the excretion under notice, and thus the inclination to it may be caused to return with considerable periodical exactness. When the disposition, however, is neglected, it will commonly after a time cease, and the feces getting indurated from the absorption of their fluid portions, costiveness is liable to ensue, and when such neg- lect is frequent, a costive habit very often becomes established. It was remarked by Hippocrates, Celsus, Boer- haave, and by other of the older physicians, that vigorous constitutions are apt to be disposed to constipation, which they regarded as indicating a more perfect digestion, and absorption of the nutri- tious portion of the aliments, and a more active perspiration. Sanctorius said, that the active and robust, discharge the remains of their nutriment chiefly by perspiration; the indolent and weak, principally by the kidneys and bowels. It is evi- dent that in relaxed bowels, owing to the rapid passage of the alimental substances, their nutritious parts can be but partially absorbed, and hence will follow defective nutrition and debility. ': People"— says Mr. Locke—"who have relaxed bowels, have seldom strong thoughts or strong bodies." * Influence of flood in the stomach upon the general system.—When food is taken judiciously, and under the incitement of natural appetite,—the digestive * On Education. 88 INFLUENCE OF THE FLOOD IN THE STOMACH organs being in health,—the stomach is agreeably impressed, and a pleasing influence is diffused throughout the system. The mere healthful action of the stomach seems competent to excite and invigorate the body, refreshment being felt almost immediately on swallowing the food. Fasting tends to irritate, while eating, if the organs are sound, soothes and quiets. Hence the reason why we feel so much disposed to discuss a man's faults while waiting dinner for him. " He was not taken well; he had not din'd ; The veins unfill'd, our blood is cold, and then We pout upon the morning, are unapt To give or to forgive."— We are doubtless so constituted that the natural play of the organs of life, that is their healthy response to their appropriate stimuli, must agreeably impress the brain; and though we cannot appre- ciate the influence of each separate function, yet the general effect is to render mere existence pleas- urable. Thus, in what is termed a physiological or healthy state, refreshment follows food and drink sleep is tranquil, imparting alacrity and vigor both to the mind and body, and in the young especially, there is a propensity to action, and a keen relish for the various pleasures of creation. Man, to be sure, from his higher nature, has many additional sources of happiness, as those of a moral and intellectual character, but it is probable that the enjoyment of most of the inferior animals is UPON THE GENERAL SYSTEM. 89 especially dependent on the pleasurable impressions experienced in their nervous system from the healthful performance of the different functions •contributory to life ; under which the gratification of their appetites will of course be comprehended. The gambols of the young animal plainly indicate to us the pleasure he derives from the simple feeling of existence. Unfortunately, however, a perfect physiological state is of rare occurrence in our own species, and it is to deviations from it, that we owe a large share of our unhappiness. When from any cause, whether owing to some change in the condition of our organs, or to excessive, deficient, or improper stimuli applied to them, there is a departure from the necessary mode of action established in the living constitution, the brain is quickly apprized of it, and a state of things very different from that described soon ensues. Our moral and physical tranquillity are disturbed; we become irritable, discontented, and perhaps despondent, and even our natural affections may be destroyed. Various physical sufferings too afflict the different organs. Such aberration of the actions of life constitutes what we call a pathological state, and the amount of pain and disturbance from it, will depend on the character of the organ or organs affected, on the nature and degree of the affection, and on the peculiar constitution of the individual. Thus a little physical uneasiness, and mental irritability, may alone be experienced, or there may be most 90 PASSAGE OF FLUIDS agonizing bodily suffering, and complete mental alienation. After eating, more blood probably being sent to the lungs, respiration is accelerated, and more full. • When the stomach is much distended, by pressing against the diaphragm, and thus impeding the freedom of its motions, it necessarily renders the breathing more difficult; and hence it is that those who habitually suffer from embarrassment of res- piration, always find it aggravated by full eating. Sometimes whilst chymification is going on, there is a paleness of the surface of the body, as though the blood was concentrated internally to contribute to this function. Some persons, too, even in apparent health, after a large repast, experience chills and flushes, or a sort of febrile action. If, subsequent to a full meal, especially of animal food, we are withdrawn from sensual stimuli, a disposition to sleep is apt to supervene. The chyme having passed into the duodenum, respiration becomes more free, the skin more active and warm, and it is now, when the task of the stomach is finished, and the chyle is replenishing and refreshing the blood, that our systems feel the greatest vigor, and are capable of the most ener- getic efforts. Passage of fluids from the stomach.—Those drinks which contain no nutriment, usually remain a much shorter period in the stomach than the food, yet of the manner in which they pass from it we have no positive knowledge. A common opinion FROM THE STOMACH. 91 is that they are transmitted by the pylorus, and like the chyle, absorbed into the circulation by the lacteals. But Magendie found that a ligature passed round the pylorus did not essentially retard their disappearance. There is certainly a good deal of evidence to show that the drinks may in part, at least, be imbibed immediately from the stomach. At any rate they find their way very speedily into the circulation, as is proved by the suddenness with which they often increase the secretions after being swallowed. Those fluids which contain nutritious matters, are either coagulated, as in the instance of milk, and their coagulum digested like any other solid matter, else their watery parts are absorbed, and the nutritious are left to be transformed into chyme. 92 DEFINITION OF APPETITES—HUNGER. CHAPTER VIII. HUNGER AND THIRST. Definition of appetites.—We may define appe- tites to be those instinctive propensities whose purpose is the preservation of the individual, and the continuance of the species. Physiologically considered, there are three, viz. hunger, thirst, and sensual love. The two former insure to the system its needful supplies of food and drink, and hence are indispensable to the life of the individual. The latter has reference to the permanence of the species. The appetites probably originate in some pecu- liar condition of their appropriate organs, which, through the intervention of nerves, affects the brain in such a way as to awaken the specific desire. It is only with the appetites which preserve the individual that we are here concerned. Hunger.—All animals, or certainly all those of the higher orders, who procure their food by a voluntary effort, are imperatively warned by this appetite of the wants of the system for new mate- HUNGER. 93 rials to supply the wear and tear consequent to its functions; and are thus impelled, and after a time by the most urgent sensations, to those mental and physical acts which are needed to answer such requisitions. The importance of the appetite under considera- tion to the intellectual advancement and happiness of man in his social condition can hardly be esti- mated. To provide for it, both the bodily and mental energies are elicited, and thus secured against the degeneracy consequent to inaction. In those southern and fertile countries, whose soil teeming with a luxuriant vegetation, precludes the necessity for exertion, man is sure to become effem- inate, and to offer an easy conquest to the active and hardy inhabitants of the more sterile and less inviting climes of the north. Though there is ever a proneness to undervalue the pleasures of everyday occurrence, still every one must acknowledge that the temperate and judicious gratification of the appetite of hunger contributes in no small measure to human happi- ness. " Had there been no pleasure,'1'' says Dr. Brown, "attached to a repast, independent of the mere relief from the pain of hunger, the coarse and equal food would probably have been taken by each individual apart, and might even, like our other animal necessities, have been associated with feelings which would have rendered solitude a duty of external decorum. It would not be easy, even for those who have been accustomed to trace a 9 94 CAUSES OF HUNGER. simple cause through all its remotest operations, to say, how much of happiness, and how much even of the warm tenderness of virtue, would be destroy- ed, by the change of manners, which should simply put an end to the social meaV * And true indeed, a change which would break in upon so many of the happy associations of domestic life, would be one of no trifling import. All our appetites contribute both directly and indirectly to our enjoyment; it is their abuse alone that is reprehensible. The low estimate in which some persons pretend to hold the pleasures of sense appears to me to savor much of affectation. We have sensual, intellectual, and moral wants, directly or indirectly connected with, and often conducive to each other ; and it is to their gratification that we owe the pleasure of existence. Causes of hunger.—Numerous hypotheses have at various periods been advanced to explain the sensation of hunger. Thus it has been ascribed to the friction of the walls of the stomach upon each other when the organ is empty; and likewise to the irritating impression of the gastric juice on its coats, when this fluid is in excess, or when no food is present for it to act upon. Dr. Beaumont re- marking that the gastric liquor did not flow spon- taneously, but only under the stimulus of food, or the irritation of some foreign substance, concluded * Philosophy of the Human Mind. CAUSES OF HUNGER. 95 to refer hunger to the distension of the vessels which are supposed to form this secretion. But the truth is we have little else than conjecture on the subject. That the sensation emanates from some peculiar condition induced in the stomach, or its nerves, by the want of food, which transmitted to the brain causes the perception of hunger,—in like manner as a specific affection of the eye occa- sions vision, and of the ear hearing,—is, to say the least, not improbable. At any rate mankind generally agree in referring this appetite to the stomach, and independent of any physiological research. Mr. Mayo thinks it not impossible that a person might be hungry without a stomach. Could life be continued after a removal of this organ, hunger might be experienced from an association like that which causes feeling to be referred to a limb after it has been separated from the body. But inde- pendent of such association, though uneasy sensa- tions might be felt indicating the wants of the system, I question much whether that specific affection we denominate hunger could exist. We know that the stomach being diseased, the natural appetite for food is commonly absent. Let it be inflamed for example, and though the system be wasting for lack of nourishment, yet even a loath- ing of food will exist. Here there is a new con- dition of the organ incompatible with that exciting the sensation of hunger, but affecting the brain in 96 CAUSES OF HUNGER. other ways, as to cause thirst, and perhaps stupor, sadness, anger, delirium. The stomach oftentimes appears to act as a tele- graph, informing the brain of the wants of the system, hunger being urgent in proportion to its need of nourishment. There subsists among all the functions of assim- ilation a striking and nicely adjusted consecutive relation. Thus if nutrition and its associate functions are energetic, demanding rapid supplies, the stomach will exert a corresponding force to furnish them, and will also call loudly on the brain in the lan- guage of hunger, that it may excite those voluntary acts necessary to the introduction of nutriment into the system. During childhood and youth, active nutrition being called for to maintain the growth of the body, digestion is rapid, and hunger frequent and impe- rious. Thus we are often amazed at the excessive quantities of food which boys will devour and digest when growing rapidly in height. Many, at this period, seem to live almost completely under the dominion of their stomachs. After profuse discharges, and during quick con- valescence from diseases under which the body has become much emaciated, as fevers for example, hunger is apt to be very urgent, and to recur at short intervals. But protracted abstinences during health, from accidental causes, as in cases of ship- wreck, are followed by a hunger far more difficult CAUSES OF HUNGER. 97 to appease, and which may for a time subdue all the delicate feelings of man's higher nature. In illustration of this, the following account from Admiral Byron's narrative, relating to the effect upon his appetite, of the privations to which he was subjected when shipwrecked on the coast of South America, has often been cited. " The gov- ernor," says he, " ordered a table to be spread for us with cold ham and fowls, which only we three sat down to, and in a short time despatched more than ten men with common appetites would have done. It is amazing that our eating to that excess we had done from the time we first came among these kind Indians, had not killed us, as we were never satisfied, and used to take all opportunities, for some months after, of filling our pockets when we were not seen, that we might get up two or three times in the night to cram ourselves." A case is on record of a rupture of the thoracic duct, and the chyle not being received into the blood, the child, who was the subject, was, while it lived, continually taking enormous quantities of food to satisfy the ardent cravings of hunger. This appetite is subject to the influence of a variety of incidental circumstances. Thus, if the mind is under strong excitement, or engaged in some interesting pursuit, the desire for food is less frequent and urgent than when it is more free. It is a matter of common observation that the idle eat oftener than the busy. Habit, moreover, obviously affects it; hence we are apt to be most anxious for 9* 98 PHENOMENA OF HUNGER WHEN EXTREME. our meals at the particular hour we have been accustomed to take them. Under its influence, too, a greater or less amount of food may be craved. Still, independent of all such influences, the appe- tite of hunger differs remarkably in different con- stitutions, some persons caring apparently but little for their meals, while others ever enjoy them with the keenest relish. Phenomena of hunger when extreme.—Hunger in a slight degree is not painful, but if not allayed, it grows more and more imperious ; a distressing sense of emptiness, or a sort of dragging, and gnawing, as commonly expressed, are referred to the stomach, and a languor and feebleness in all the important functions are experienced. If its de- mands still remain unanswered, phenomena of the most afflicting character are soon manifested. The peculiar distress in the stomach becomes extreme, and all the powers of the mind as it were absorbed by it, reason may partially or entirely yield, and languor, gloom and despondence alternate with the feverish ravings of madness, oftentimes associated with acts of the most brutal ferocity. Thus in accounts of shipwrecks, scenes are often described most shocking and humiliating to our nature; where the starving wretches have not hesitated to murder and feast upon their companions, or even to gnaw the flesh from their own bones. So im- perious is the instinct of self-preservation ! All know how daring and ferocious the inferior ani- mals become under the excitement of hunger ! VORACIY. 99 Voracity.—Habit induces many persons to take much more food than is required for the purposes of nutrition. When the stomach has been accus- tomed to frequent distension, it gets at length into such a state that it is uneasy without it; and thus food is demanded not merely to supply the natural wants of the system, but also to administer to the factitious cravings of the stomach. The idle are particularly in danger of falling into gluttonous habits,—"let a man," says Dr. Good, "have nothing to do, and he will be almost sure, when- ever he has an opportunity, to fill up his time by filling up his stomach." Cases, however, occur of what are termed buli- mia or canine hunger, where the appetite from early infancy, or from some after period of life, craves incredible quantities of food, and unless abundantly supplied, the faintness and uneasiness at the stomach become very distressing. It is somewhat remarkable, too, that its subjects are often slender, or perhaps even unnaturally emaci- ated. Its causes doubtless vary in different instances. It may sometimes, as has been sug- gested, be dependent upon an error of structure or position of the stomach, causing the food to be too quickly discharged from it. It not unfrequently, however, is the result of some morbid state of this organ, or of the system. It is well known that the irritation of worms in the stomach, or upper portion of the small intestine, will manytimes keep up a most importunate hunger. There are, too, certain 100 VORACITY. capricious longings, happening under peculiar cir- cumstances of the constitution, where astonishing quantities of the article desired are eaten and di- gested. Thus we are told of a lady who, longing for herrings, devoured four hundred at a meal. Still, voracity does occur in seemingly good health, at least in all other respects, and the food is rapidly digested. As a matter of curiosity I will cite from Dr. Good's Study of Medicine, the two following re- markable cases of this canine appetite. The former has been often quoted, and seems to be pretty well authenticated. It occurred in a French soldier named Tarare, and was communicated by M. Percy to the National Institute of France. "Before his enlistment, he was in the habit of devouring enormous quantities of the coarsest flesh, fruits, and roots: and, subsequently, he was found, after swallowing his own rations, to feed on the refuse of his comrades' messes, or offensive meat thrown on the dunghills ; and to devour cats, dogs, and serpents. M. Fournier tells us, that at seventeen years of age, when he weighed only one hundred pounds, he could devour, in the space of twenty- four hours, a quarter of beef as heavy as his body; and that, on one occasion, when in the army, he devoured in a few minutes a dinner prepared for fifteen German laborers, and composed of various substantial dishes. He was strongly suspected of cannibalism; and was often repulsed with diffi- culty from the ward appropriated to the dead. FASTING. 101 He at length fled from the army in consequence of a rumor that he had devoured a child sixteen months old, which had suddenly disappeared." The alvine evacuations of this individual were not very great, but he sweated very profusely. The' next is a case related by Dr. Mortimer, and happened in a boy only twelve years old, "who from a feeling of inanition, had so strong a craving that he would gnaw his own flesh when not sup- plied with food; when awake, he was constantly eating: the food given him consisted of bread, meat, beer, milk, water, butter, cheese, sugar, treacle, puddings, pies, fruits, broths, potatoes; and of these he swallowed, in six successive days, three hundred and eighty-four pounds avoirdupois; being sixty-four pounds a day on the average." This was connected with disease, and lasted for a year; and the food was usually rejected a short time after it was swallowed. Fasting.—We have on record many curious ex- amples of persons subsisting on very small quanti- ties of food, and cases also where perfect abstinence has been protracted during long periods. Haller, and others have given instances of fasting continued for years. Such stories however are too improba- ble to be admitted on the imperfect evidence which exists in regard to them. There are, however, numerous well authenticated examples of fasting, for ten or twelve days ; and where water was to be had, for twenty, thirty, or even longer. Dr. James M' Naughton, professor of anatomy in the 102 FASTING. university of the State of New York, published, some years ago, an account of a medical student who lived on water alone for fifty-three days. The case of Ann Moore, which called forth so much interest in England, was certainly a very remarkable instance of fasting. Though this fe- male did not, as was pretended, live wholly with- out food and drink, yet the committee appointed to watch her, reported it as their opinion that she could endure the privation of solid food longer than any other person. Her principal support was de- rived from tea and water. Her circulation, and indeed all her vital actions were remarkably feeble, and she was altogether confined to her bed. Persons, from habit, and under the influence of certain incidental circumstances, will often be ena- bled to subsist on a comparatively very small amount of food. Every thing tending to reduce the vital movements, and of consequence, the waste of the living fabric, as a spare and dilute diet, quie- tude, and the avoidance of stimuli, both external and internal, will of course lessen the demand for nutri- mental supplies. Thus in some reduced states of the system, associated with chronic disease, and likewise in fevers, where the secretions and excre- tions are greatly diminished, and the body is also kept at rest, long periods are often passed either without any nutriment, or with but very little; whereas the active and healthy can generally sub- sist but a few days if debarred entirely of nourish- ment. Hence persons Avho are deprived of food, FASTING. 103 or on short allowance, will endure their abstinence better by remaining inactive. The vital actions being more sluggish in the cold than in the warm blooded animals, the former are generally capable of living longer without food than the latter. Animals who pass into a dormant or torpid state, that they may survive the cold of our northern winters, continue many months without any nour- ishment, other than what they derive from the absorption of their fat, which is usually abundant when they retire for the winter. The degree of torpidity varies in different animals, and under different circumstances of the same animal; but in its most perfect state, the actions of life are hardly perceptible, and hence the waste of the body, which bears a correspondent relation to the activeness of the functions, is very trifling, or no more than what can be repaired by the gradual absorption of the fat. In this dormant condition, frogs and toads have been found in the depths of the earth—enclo- sed in the trunks of trees, and even in solid rocks, where they must have been imprisoned for years, and in some instances, probably for ages, entirely deprived of food, and on being restored to warmth and liberty, quickly resumed their active life. Here was a most complete state of torpidity, life approaching its condition in the seeds of plants, which can retain their germinating power, or vital principle, for indefinite periods, but which, were it quickened into action by warmth and moisture, might not exist beyond a single season. 104 THIRST. Instances are even recorded of human beings falling into a sort of apoplectic sleep, called a trance, and continuing in it, without food, even for months. Van Swieten, in his commentaries, tells of a nobleman of Lausanne, who fell into a deep sleep, which lasted for six months ; at the end of which time arousing, his first question to his ser- vant was whether he had fulfilled some directions which he had given him at the moment of his attack. Thirst.—This appetite urges to the swallowing of liquids to soften and dilute the food, and to supply the expenditure of the fluid materials of the body. There are a number of animals, however, and even of the higher order, that do not drink, as, according to Blumenbach, mice, quails, parrots, and others. Even in our own species, instances now and then occur where drink is never craved. Sauvages, and other medical writers have related cases of persons, who from some peculiarity of constitution never thirsted. Dr. Good cites an in- stance told by Founder of one of his most intimate friends, who reached the age of forty-eight without ever having drunk any fluid, or been thirsty; but he was in the habit of eating voraciously, and what is curious, he died of dropsy of the chest. "I have," says Dr. Paris, " a lady of fifty years of age at this time under my care, who has declared that she is perfectly unacquainted with the nature THIRST. 105 of thirst."* In such examples there must be but small expense of the fluids of the body by the ex- cretions. It ought to be borne in mind, however, that much liquid matter is both naturally and arti- ficially united with our aliments. In fruits and fresh vegetables, it is particularly abundant, and hence the character of the diet must greatly in- fluence the demand for drink. Still, different individuals, all other things being equal, crave different quantities of fluids, and I have known many persons, Avho, though yielding to the habit of taking liquids periodically, yet very seldom experience any sensation of thirst. This appetite is promoted by various circum- stances, as dry food, salt, and rapid waste of the fluids of the body, as in profuse perspirations. Violent passions of the mind, diminishing the se- cretions of the mouth and fauces, and creating a feverish condition of the system, at the same time that they destroy the appetite for food, often greatly excite the thirst. Severe bodily suffering also pro- duces the same effect. We are told that under the cruel torture formerly inflicted to extort confes- sions, the most distressing thirst was commonly experienced. A close and vitiated atmosphere produces also the most urgent craving for liquids. In Mr. Hoi well's narrative of the sufferings en- dured by himself and companions in the Black • On Diet. 10 106 THIRST. Hole in Calcutta, he says that the atmosphere becoming gradually more and more vitiated, " be- fore 9 o'clock every man's thirst grew intolerable, and respiration difficult. In this distressing situa- tion, the prisoners cried loudly for water; and when water was at length brought by some of the guards, with such eagerness did they struggle to get it, that not only the greatest part of the water handed in hats through the bars of the prison was spilt before it reached any one's lips, but many were trampled down and suffocated, while others, particularly those who stood near the windows, were pressed to death." Habit exercises a marked influence over this, as over our other appetites: Man, uninfluenced by the luxury of civilization, and partaking only of a wholesome diet, would probably crave drink in such quantity only as to moisten his food when dry, and to meet the necessary waste of the animal fluids, and that would be water, or the juice of fruits and vegetables. But the free employment of high-seasoned food, and exciting liquors, so common in a state of society, serves to create a factitious thirst, which is maintained and aggra- vated by the very means used to quench it. Hence it is that by many, the providing of choice liquors is made an important business of life, and the administering to such unnatural thirst is ranked among the highest of enjoyments. And too often it happens that this necessary appetite becomes an THIRST. 107 occasion of the destruction of health, and of all the noble faculties which distinguish our nature. As some persons from peculiarity of constitution demand very little drink, others on the contrary crave vast quantities. This excessive thirst, is technically called polydipsia, and has occasionally been hereditary. In some well authenticated in- stances, thirty or forty pints of fluid have been required in the twenty-four hours to satisfy the thirst, and even four hundred are said in certain cases to have been swallowed daily. Such unnat- ural desire for liquids is usually the consequence of some morbid condition of the system. The sensation of thirst is ordinarily referred to the mouth, fauces and pharynx. The secretions of these parts being lessened, they get dry and parched, and hence arises an ardent desire for liquids, particularly such as are cold and acidu- lated, to moisten and cool them. If the want is not satisfied, it grows more and more painful, the heat and dryness in the mouth and throat are aug- mented, and appear to extend through the chest. The secretions become more and more thick, scanty and adhesive, swallowing consequently being ef- fected with much difficulty, and the longing for cold water is most urgent and distressing. Various other phenomena, too, soon follow, all of which are well exemplified in the burning thirst attendant on violent fevers. Dryness of the mouth and throat, though com- monly, still is not necessarily associated with great 108 THIRST. tliirst, instances occurring where these parts are dry and parched but without accompanying thirst. In some instances, too, the secretions from the glands of the mouth are very copious, and still there exists an urgent craving for drink. And, moreover, the local application of liquids to the mouth and throat has but little effect in assuaging thirst. A case, by Dr. Gairdner, is published in the sixteenth volume of the Edinburgh Medical and Surgical Journal, of a man who had cut through his oesophagus, and who suffering from a most insatiable thirst, several buckets of water were swallowed daily, but, being discharged through the wound, without allaying it. On inject- ing, however, a fluid into the stomach, the thirst was soon quenched. It is said- too, that the desire for drink may be abated by injecting liquids into the veins. This appetite then would seem to be excited by a necessity on the part of the system for fluids, the common effect of which is to occasion a dryness of the mucous membrane of the mouth and throat, and doubtless also to influence the secretions of the stomach, which induced circum- stances aid in awakening the specific desire. Thirst, though accompanied perhaps with less physical exhaustion, yet when protracted, the suf- fering from it is even more intense than from hunger, hence no punishment inflicted by the heathen divinities is more often adduced than that of Tantalus. Hunger and thirst are when slight, FOOD OF ANIMALS. 109 incompatible sensations, but after long deprivations of food and drink, are both experienced, and the thirst is apt to be the predominant affliction. CHAPTER IX. GENERAL REMARKS ON THE FOOD OF ANIMALS. There is a dependence upon each other, either direct or indirect, among all living beings for their nutrition. Plants to be sure derive their support immediately from inorganical substances, as water and air, but then matter which has been endowed with life, or some of its products, are generally required to enable the soil in which they grow to afford them nourishment. Animals, or certainly all of the higher orders, though they make use of some mineral substances, as salt and water, yet are mainly indebted for their sustenance to living bodies. Life in a particular manner contributes to the circulation of matter, or to those unceasing muta- tions which are so essential in the scheme of the 10* 110 GENERAL DIVISION OF ANIMALS, universe. Thus plants, interposed as it were be- tween mineral matter and animals, prepare the former for the nourishment of the latter, vast tribes of whom live on vegetables alone, and which being wrought into their own bodies, serve as food for still other animals. A reciprocal system of des- truction, and a continued transmigration of the materials of life, are the only conditions on which it can be maintained, and indeed were it otherwise, the necessary relation between organic and inor- ganical matter would soon be destroyed, or the earth would become overburdened with vital existences. General divisions of animals, founded on the nature of their food.—We have three general di- visions of animals established on the character of their diet. Phytivorous, or those which feed ex- clusively on vegetable substances; the term being formed from the Greek and Latin words, ir in proximity with the earth's surface is probably never entirely free from unessential mixtures. A minute and variable amount of car- bonic acid, or fixed air, is always detected in it. Watery vapor, too, in different proportions is ever united with it; and the aroma of plants, and more or less of the numerous gases given off during respiration, combustion, and the decay of animal and vegetable substances, are oftentimes present. Of these mixtures, the watery vapor is necessary to our existence, and the pleasing odors from many varieties of the vegetable kingdom, may be con- ducive to health. But then others, as some of the subtile effluvia and gases emitted from decay- ing organized matter, are extremely pernicious to human life, and are doubtless a source of many of the severe and fatal maladies with which we are afflicted. The character of the air, it is obvious, must vary in different situations, as in the interior and on the sea cost; in crowded towns and in the open coun- try, in valleys and on hills. It is doubtless, too, CHANGE OF AIR. 345 affected in a measure by the nature of the soil. At night it grows more damp, and when noxious impurities exist in it, they apparently become more concentrated and active than by day. In winter it is of course more dense than in summer. Such varying conditions in this essential vital agent cannot but influence to a greater or less extent the living functions, and among the rest that of diges- tion. Sometimes this influence can be readily appreciated. Thus the dyspeptic inhabitant of a city will almost always gain advantage from the relatively pure air of the country. Even a very short residence in it will oftentimes effect an aston- ishing improvement in his looks, appetite and digestive powers, and independent, too, of any increase of the customary exercise. " Notwith- standing," says Mr. Thackrah, " the distance to which the atmospheric impurity of Leeds extends, a mile or two has a sensible effect on health. A man who has lost his appetite for breakfast while working in the centre of the town, will often im- mediately regain it, when he enters a similar employ at the outskirts." Change of air.—Observation teaches the fact,— though philosophy has not explained it—that mere changes of air, even when nothing is gained in respect to its purity, will oftentimes exert a very happy influence on the digestive function. Thus a removal from the sea coast to the interior, or from the latter to the former, is not unfrequently attended with manifest advantage in dyspepsia. 30 346 CLOTHING.—-SLEEP. And the same is true of other changes, even where there is no appreciable difference in the character of the atmosphere. Clothing.—The body in dyspepsia should always be maintained at such a temperature as is agreea- ble to the Sensations. The clothing, therefore, is to be regulated by the daily atmospherical vicis- situdes, and the varying ability of the system to support them. The unsteadiness of our own cli- mate demands frequent changes of dress, often even during the same day. The feet, in a special manner, should be carefully defended, and main- tained at a grateful degree of warmth. In damp and variable climates and seasons, flannel becomes a necessary article of clothing. Its utility during the day will be greatly enhanced if it be taken off at night. When worn in con- tact with the skin, for the sake both of warmth and cleanliness, frequent changes of it become necessary. Sleep.—An adequate amount of tranquil sleep being of the highest moment to the welfare of diges- tion, the dyspeptic invalid should use " all appli- ances and means to boot" to secure to himself its full benefit. The day, for reasons too plain to need enumera- tion, is properly devoted to action, and the night to repose, and whenever, either for the sake of business or pleasure, this order of things is inverted, the health, if not immediately, will in the end almost surely suffer. SLEEP. 347 In respect to the necessary amount of sleep, so much is dependent on habit and constitution, that no rules of universal application can be established. Few persons, unless under the influence of injudi- cious habits, require more than, seven hours of sleep; and to many, five or six, and in occasional examples even less, afford all the refreshment that is needful. Broussais tells us that some individuals throughout the whole course of a long life are contented with one or two hours of repose; but if such instances exist, they must be exceedingly rare. It is natural to infer that those who sleep soundly will require the least time for repose, as in them most of the animal functions are simultaneously resting, while in unsound sleepers, they rest as it were by turns; that is, portions of the nervous system are awake or excited, while others are asleep. Dyspeptic subjects who are irritable and. watch- ful, are often obliged to remain in bed, eight, nine, or ten hours to obtain six or seven of sleep. Excessive indulgence in sleep will always be found injurious in indigestion, and dullness, head- ach, and diminished appetite, are apt to be its immediate consequences. It is proper therefore to rise, if sufficient rest has been obtained, on first waking in the morning, and not, as is too often practised, lie drowsing and dreaming, and encour- aging enervating fancies of gloom or pleasure long 348 SLEEP. after the system has received all the refreshment which sleep can impart. Tranquil feelings being essential to quiet sleep, all undue excitement during the evening should be scrupulously avoided. The sleeping apartment ought to be large, well ventilated and quiet. If an irritable dyspeptic invalid is disturbed by noises after going to bed, his night's rest may be com- pletely interrupted. Lights are very improper in a bedchamber; injuring the purity of the air, and— especially in those unaccustomed to them—tending, by their sensual impression, to excite the brain. It is furthermore highly important that the body be comfortably warm on retiring to rest, and that it be maintained so during the night by sufficient and proper bedclothes. Lying either too hot or too cold is always injurious to digestion. If a dyspep- tic invalid goes to bed with cold feet, they may continue in this state even through the whole night, and the sleep in consequence be disturbed and \ unrefreshing. In the warm season, at least, a mattress should always be preferred to a featherbed. It is better, as a general rule, that the night alone be appropriated to sleep. Sleeping after dinner, certainly for any considerable time, and in the horizontal posture, probably retards rather than hastens digestion. Celsus advised to remain awake some time after eating freely. Unless under the influence of habit, of fermented liquors, or of full meals of animal food, a propensity to sleep will not commonly exist during the day. It is in cases BATHING. 349 only of much debility, and where the rest is inter- rupted at night, that I conceive day sleep to be admissible. Bathing.—The bath, by cleansing the skin from impurities, contributes to the perfection of its func- tion, and consequently to the health of digestion; and under certain modes of its application, a stim- ulating influence is imparted to the vascular and nervous systems, and consequently through them extended to all the functions. But the refreshment and alacrity that are usually experienced after judicious bathing, amply prove its utility. It is particularly requisite in hot weather, and when exposed to the dust, and other impurities existing in the atmosphere of crowded cities. Bathing, however, is liable to abuse, and when extravagantly indulged in, and as a voluptuous gratification, may tend to enervate both mind and body. Such was its perversion, and such the necessary consequences, in the advanced days of Greece and Rome. Though the people of both these countries at first constructed their baths in reference to health and cleanliness, they at length became subservient to pride and sensuality. The ruins of ancient baths in Rome, as of Titus and Caracalla, as also in other parts of Italy, fully attest the height of luxury to which this gratifica- tion was carried. Those of Caracalla, for example, contained sixteen hundred cellae, or bathing places, beside labra, or immense bathing tubs of granite 30* 350 BATHING. and porphyry, and the whole edifice was on a scale of the most splendid and costly magnificence. In Rome, it is said, there were eight hundred and fifty-six public baths, that is, such as might be used by the people free of expense; and some, as those of Dioclesian and Caracalla, were capable of accommodating near two thousand persons. Under the emperors, the taste was more particularly for the enervating enjoyment of the hot bath. "After the overthrow of the republic," says Dr. Currie, "the Romans consoled themselves for the loss of their freedom, by a more unbounded indulgence than ever in those sensual gratifications which had led to their fall. Of these, the pleasures of the bath formed a distinguished part, they sought every means of heightening and diversifying them, and connected them with other epicurean enjoy- ments. The mild and tepid immersion of the Greeks no longer satisfied them; they heated their baths to the utmost pitch of endurance; and as they rose reeking from their surface, vessels full of cold water were dashed over their naked bodies, as a high gratification in itself, and a means of stimulating the senses to gratifications still higher. Such practices could not, however, be continued without injury. In the bagnios of Imperial Rome, the last of the Romans, the followers of Zeno and of Cato, sought to soothe their sorrows, and were melted down into slaves; the powers of their minds became enfeebled, the vigor of their frames decayed, COLD BATHING. 351 and they lost for ever the bold impressions of freedom and of virtue." * In America, however, we err in the opposite extreme. Private accommodations for bathing are by no means frequent among us, and public ones, except in our principal cities,—and even here they are not often very extensive or inviting—are gen- erally unknown. Cold bathing.—In the warm season, and prac- tised with prudence, cold bathing is highly invig- orating, and in many cases of dyspepsia may do much toward the restoration of the digestive energies. Thus dyspeptic subjects often derive great advantage from prosecuting, during the warm months, a regular system of sea bathing. Salt water being more stimulating to the surface than fresh, its use is more certainly followed by reaction. The effect of cold bathing will vary somewhat according to the particular mode in which it is practised. Sudden and general immersion in cold water is always safer than a more gradual, or especially a partial subjection to its action. Thus many persons who could safely plunge into cold water, might suffer in their health were a small stream of it allowed to pass gradually down the neck and back ; just as a current of cold air acting on a part of the body, is attended with more danger than general exposure. • Medical Reports, p. 126 352 COLD BATHING. The cold shower bath produces a powerful im- pression on the system, which, when there is strength to endure it, is highly invigorating to the function of digestion. Sponging the body daily with cold salt water, is oftentimes attended with striking advantage to the digestive powers. Some persons even continue it through the cold season, and beside the benefit mentioned, experience in consequence a remarkable diminution of susceptibility to atmospherical im- pressions. It should always be brief and brisk, and the body, immediately subsequent to it, be wiped perfectly dry with a coarse towel. The safest time for cold bathing is when the body is warm, and the functions are most active. It may therefore be prudently employed in the midst of the excitement of exercise, but not when sweating is profuse, and the system begins to experience fatigue and exhaustion. Hence it is proper in the early, but never in the latter stages of severe exercise, when the living energies are beginning to decline. The Roman youth in the heat of their exertions and excitement in the Campus Martius, found refreshment from plunging into the Tiber; and it is now a common practice among the Russians, after heating themselves in baths of a temperature from 106° to 116° Fahr., suddenly to roll naked in the snow. The safest period for cold bathing is a few hours after breakfast. It ought never to be practised immediately after a meal, unless it has been very WARM BATHING. 353 sparing, the system always displaying less force of reaction when its powers are engaged in the accomplishment of chymification. Thus bathing immediately after dinner, will, in the subject of dyspepsia, very frequently be followed by chilli- ness, with headach, and various other symptoms of disturbed digestion. If too, the cold bath is used in the afterpart of the day, and especially at night, when the vital energies of the system are in a measure declined, similar results are liable to happen, and a restless night is the frequent conse- quence. A little brisk exercise, or friction over the surface, immediately preceding and following the use of the cold bath, will contribute to the security of reaction. At first, certainly, the immersion should last but a few minutes, and should be as complete as possible. If speedily on leaving the water a glow of warmth is felt diffusing itself throughout the surface, the safety of the remedy is amply evinced. But when on the contrary, the body continues chilly for a considerable time, and languor and headach supervene, incompetency of reaction is shown, and persistence in the measure will be unsafe. When cold bathing is well borne, and the system has become habituated to it, it may be pursued daily; but at first, it will be most prudent to employ it only every other day. Warm bathing.—In some instances of dyspepsia, a more salutary influence is experienced from the 354 WARM BATHING. warm than the cold bath. Such is remarked to be the case in those forms of it connected with mani- fest disorder of the biliary system. Here warm saltwater bathing practised daily, or on alternate days, and accompanied with a good deal of friction on the skin, is generally a very valuable remedy. Analogous principles, in some respects, should regulate this, as the other variety of bathing. Thus its most suitable period is between the hours of breakfast and dinner, as a few hours previous to the latter meal. Used soon after eating, it is very liable to interfere with digestion, and con- sequently to aggravate the dyspeptic symptoms. Kestlessness, too, will sometimes follow its use at night in the subjects of indigestion. The period proper to remain in the warm bath, is about twenty minutes, and the body ought all the time to be immersed. Its temperature should be constantly maintained at such a standard as to impart an agreeable feeling of warmth, and hence will require to be varied according to different circumstances of the system, and of the external atmosphere. Oftentimes the heat which seems too great at first, owing to its contrast with that of the air, will after a while require even to be raised to satisfy the sensations. An agreeable temperature to most persons is about 90° Fahr.; to some it is more pleasant a little above, to others rather below this point. If the bath, however, be rendered too warm, a feverish excitement, marked by a hot and dry skin, headach, restlessness, &c., will sometimes TONICS. 355 ensue. I have not rarely noticed such effects from a hot bath taken at night with the view to promote sweating. The effects, however, of the warm bath, certainly vary in different constitutions, and under the influence of habit, and on first commencing its use,-great prudence is demanded in its manage- ment. In the winter season it is of course the only form of bathing ordinarily employed. In dyspepsia, however, unless, as before men- tioned, there is marked disturbance of the hepatic function, cold bathing is generally to be preferred in the warm season; and it is more particularly proper in those cases characterized by extreme nervous irritability. Tonics.—A class of substances generalized under this name, and supposed to increase the energy of the stomach, and through it, of the various other organs, is in very familiar use in indigestion. Vegetable bitters are the tonics most commonly employed, and at times, they obviously improve the appetite, and elevate the powers of the stomach; still in some constitutions, and in certain forms of the complaint, their effects are uniformly injurious, wherefore an indiscriminate resort to them is improper. The most gentle and safe tonics, are quassia, cascarilla, dandelion and chamomile, in watery decoction or infusion. Long persistence in their use is rarely advisable, and they are never to be taken in large quantities. 356 CONCLUSION. CONCLUSION. Though I have now said all on the treatment of dyspepsia, that comes strictly within the plan of the present volume, yet there are two symptoms, oftentimes very troublesome, and for the relief of which much may be accomplished by a proper management on the part of the individual, con- cerning which a few brief remarks in conclusion may not be unuseful. I allude to constipation and heart-burn. Habit exercising a very marked influence upon the regularity of the bowels, periodical observances in respect to them are of important consideration. In dyspepsia, a daily dejection is commonly requi- site, and such will be the more certainly insured by appropriating to it a particular period. Much may also be effected toward subduing a costive habit by a judicious choice of diet. Thus, bread made of unbolted wheat, or of a mixture of rye and wheat flour, should be selected. Two or three figs, or a few prunes, if the stomach will bear them, may be occasionally eaten with advantage. To the laxative influence of the fresh subacid fruits I CONCLUSION. 357 have already alluded. Molasses has also mild laxative properties, and is hence oftentimes used advantageously in the diet of those who suffer much from constipation. When candied it becomes more digestible, being far less apt to pass into the acetous fermentation in the stomach, than when raw. A natural passage from the bowels will generally be favored by rising early in the morning, taking a draught of pure water, and then, previous to breakfast, walking a short time in the fresh air. Lying late in bed is very apt to aggravate consti- pation. By a cautious management of this sort, the necessity of resorting to active cathartic medi- cines will often be escaped, which is particularly desirable, since the relief afforded by these is mostly transient, and their ultimate tendency is to aggravate the evil they are designed to correct. That these medicines are never demanded I would by no means assert, but they certainly should be employed as rarely as possible, and only to such extent as to accomplish the purpose in view. Ac- tive cathartics are very seldom required in the present malady, except to subdue incidental symp- toms, and then can be safely employed only under the immediate direction of a physician. Many of the patent cathartic pills in common use comprise mercury, antimony, and other energetic ingredients, and hence, though perhaps affording temporary relief, their final result is to impair still further the health of digestion. 31 358 CONCLUSION. Cathartic medicines, when there is a necessity for their employment in dyspepsia, should be so managed that in their effects they may imitate as nearly as possible the natural action of the bowels. Thus, taken in minute quantities with the food, and often repeated, they will usually in a little while accomplish the desired purpose ; and when the bowels are once brought into a free state, unless the tendency to constipation is quite obstinate, a very slight cathartic influence daily renewed, in union with a proper regulation of the diet, will be sufficient to continue them in it. The advantage in taking these substances with the food is, that by becoming blended with and diffused through it, less irritation is experienced from them by the stomach. Heart-burn being, in the greater proportion of cases, dependent upon an excess of acid, alkalies are generally its most effective remedy. These unite chemically with the superabundant acid, and a mild neutral salt is the result. When too the affection is owing to the irritation of fatty aliments which have become rancid in the stomach, the same remedy will likewise tend to alleviate it by combining with them and forming a compara- tively bland saponaceous compound. Carbonate of soda, or the common soda of the shops, is one of the mildest and least unpleasant alkalies, and hence is very commonly employed in heart-burn. When there is an excess of acid in the stomach, its use will be followed by an extri- CONCLUSION. 359 cation of carbonic acid gas, which, if the organ be not too delicate to bear the distension, will act as an agreeable stimulus to it. Other alkalies and alkaline earths are also used with similar results. Magnesia possessing mild laxative qualities, may be advantageously employed in heart-burn when occurring in those of consti- pated habits. Finely powdered, and purified charcoal, taken four or five times a day in the dose of a small spoonful, will oftentimes act as a pallia- tive of the symptom under notice. This substance may also be useful in other points of view, serving in a degree to correct the unnatural fermentation in the food, and consequently the acrid and putrid eructations, and the offensive odor of the breath so frequently connected with indigestion. Some of the mild subacid fruits, as likewise the mineralacids, will manytimes afford relief in heart- burn, even when it arises from morbid acidity; which effect may be explained on the supposition that they promote the natural function of the stomach, and thus enable it to resist those chem- ical changes in the food which are the common cause of this disagreeable affection. RECENTLY PUBLISHED BY T. H. CARTER. A TREATISE ON CONSUMPTION AND CHANGE OF CLIMATE; adapted for general readers. By William Sweetser, M. D., &c. &c. 1 vol. $1,25. From the numerous favorable notices of this work, we make the following extracts:— " There are not it is presumed, many men in New England who could have produced a volume like the one to which these observations refer. Not because there is a scarcity of good writers. Very many, eminently distinguished for their knowledge of science which gives them high claims to distinction, would have made a miserable exhibi- tion of their talents, were they constrained to omit technica ities, which, with them, are almost indispensable representatives of their best thoughts. Thinking learnedly, and expressing sentiments or giving advice in a simple manner, so that others, without an elementary pre- paration, may clearly understand, is by no means a common circum- stance.—The Treatise on Consumption, by Dr. Sweetser, combines certain advantages unknown jn the pages of medical works in general. Whilst it is calculated to instruct physicians, every person of ordinary capacity may reap the full benefit of the author's labors. There is no ostentatious display of obscure terms, to impress the multitude, for whom he seems to have written, with the profundity of his researches: it is remarkably free from distortions of language, and abounds in good sense and sound medical philosophy."—[Boston Medical Journal. " We have indeed seldom read a popular treatise upon any medical subject, in which fewer errors occur, or in which a larger amount of valuable information is so happily condensed."—[American Journal of the Medical Sciences, Philadelphia. " The remarks on differences of climate, and the benefit to be de- rived from journeys, voyages, and a residence abroad, is treated in a manner which shews that the author has visited many of the places usually resorted to in Europe by invalids, and the results of his obser- vations while abroad, are given in so clear and unprejudiced a manner, as to be especially valuable for all, whether sick or well, who intend to travel or reside in Europe."—[Daily. "The subject is treated with such clearness, and presents so many considerations of practical importance, that the utility of this treatise must be recognized by the public to whom it is offered."—[Boston Atlas. " We like it because it is full of practical and well digested knowl- edge, conveyed in a common sense and practical manner, such as the purpose demands."—[Transcript. " A work which offers so much to commend and so little to criticize should be in the hands of all who may need advice on this too fatally interesting subject; that is, of at least one quarter of the community." [American Monthly. ft {D L i j*v »: \/^ i ^V i \^\ 3 ^ VISIT IVNOIIVN INOIOirV dO AIVI ..1 TVNOIIVN 1N.3.01W dO milll T * - * , OF MEDIC, NE " NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF U ,,1911 TVNOIIVN JNDiaiW dO AIVI9IT IVNOIIVN 1NI3IQ3W JO AS V SB M 1 MEDICINE NATIONAL LIBRARY OF c ilVIIII IVNOIIVN INI 3. Q3W dO 1IVIII1 IVNOIIVN 3 N I 3 I a 3 W d O A a V a « .1 • IAIY OF MEDICINE N A T I O N A I I I B R A R Y O F M E 0 I C . N E N A T I O N A I L I B R A R V O F MARY OF MED, CINE NAT.ONAL L.S.A.Y OF MEDICINE ^NATIONAL LIBRARY O I 3NI3IQ3W JO AIVIII'T TVNOIIVN 3NI3IQ3W dO AIVI9I1 TVNOIIVN 3NI 1 IN I3I03W dO AIVIBIT IVNOIIVN 3 N I 3 I 0 3 W d O A I V I 9 I 1 1 V N O I 1 V N 3NI E NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NA < y\y e \^l #819«^<| w\ j Kx* 'iHi^^i. m i v vyv:.iWiir,ifeW '.■'■•■'vsv.iv'.-.'i'v'^iiyiisp