■ jl.» I 9 iffl ill II I 11 ■ lOfff] ffilJ full Bill mn ■ m Warn II UuSi IIHnHH ■IBHHSSi ess stmiimffl EfyHRiBiiii IhISIHhsIIISIhI I ■! Si SMS! ■u WM HI HHfl BBBmBmI affiifl BHttHHliBIll RtBl (lass BookJB_5t5 SMITHSONIAN DEPOSIT. / / ON FOOD AND ITS DIGESTION. LONDON PRINTED BY STOTTISWOODE ANI> NEW-STEEBT SQUARE i H O ON FOOD AND ITS DIGESTION: AN INTRODUCTION TO DIETETICS. BY WILLIAM BRINTON, M.D. FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS : imitsician to rr. tdomii'i hospital, and lecturer on phtsiolocv in that institution. WITH FORTY-EIGHT ENGRAVINGS OX WOOD. /#% LONDON: LONGMAN, GREEN, LONGMAN, AND ROBERTS. 1861. c ,\j *v * PREFACE. The following Treatise is intended to describe the process of Digestion, in its natural connection with the Food on which it operates, and with the purpose which that Food, ; ius elaborated, fulfils. In so far as it answers to this intention, it differs from of the works on Diet hitherto published. It gives a e complel unt of tl s tns of Digestion, &s both their structure and function. It illustrates the relation of Digestion to Nutrition, by referring the details of the demand for food to those of that process of bodily waste by which this demand is dictated. Endea- vouring specially to harmonise the study of Food with that of Digestion, it everywhere keeps the Natural History of the various alimentary substances in clue subordination to their practical bearing on life and health. Hence, while chiefly discussing the articles of food commonly used in this country, it views these from a rational rather than an empirical aspect : in order to seek out the phy- A 3 vi PREFACE. siological principles of their use, bo far as these are cernihle by the light of our existing knowledge. In b! it treats the whole subject of Digestion as a natural sub- division of the "Institutes of Medicine:" and especially dwells on the Physiology of Food, as constituting a I for the Practice of Physic, in reference both to the vention, and to the cure, of Diseasa Such a plan is so closely akin to that adopted bj the Course of Physiology at St. Thomas's Hospital, tl I 1 make no excuses for reproducing in thi- materials already included in my Lectures on Digest and published as part of the arth In- testine," in the Cyclopaedia of Anatomy and Physi As little am I disposed to apologise Eot I not only the matter, but tin' manner, of the Lectin An author will scarcely handle hi- Bubjed aright, he have some definite idea of the readers whom h addressing. And even where I have most di the Course of Lectures above alluded to, I have at imagined myself speaking to an audience like that which it has for many years been my duty to address on the same subject. If, in uttering the ph which I have formed, the desire to suggest, to illi and even (so for as is fitting) to interest and amufl . led me beyond the conventional boundaries of scientific authorcraft, the reader will perhaps recollect that 1 1 specially addressed myself to students : who. as PREFACE. Vll are generally glad to receive any illustrations which may help to clear up the obscurities of a subject ; and appear to reserve all their intolerance for pedantry and cant. Indeed, save as a Lecturer addressing an audience of students, whose specific requirements dictate and limit his duties, I could scarcely have written the following pages at all. The vast field for successful research offered by structural Disease, and the special responsibilities, as to the cultivation of Pathology, which every Hospital Phy- sician by implication undertakes, would of themselves have sufficed to prohibit my entering on the merely curious or literary aspects of the subject of Food. And increasing professional avocations have so trenched upon the scanty leisure at my disposal before beginning this book, that, however restricted its plan, nothing short of the engage- ments I had entered into could have induced me to finish it. The delays incident to the paramount claims of practice have not, I trust, prevented my giving a conscientious revision to the whole subject ; and especially to some Die- tetic questions attracting great interest in the present day. Violent as is the controversy which these questions seem generally to provoke, it would perhaps be presumptuous in me to aspire to the honour of a condemnation by those holding extreme opinions on both sides. But, failing to obtain this typical success, I shall still hope to have been useful ; both by suggesting some truths for further consi- deration, and by pointing out some plausible errors, the exposure of which may tend to advance our knowledge. viil PREFACE. In accordance with a plan adopted in my Lecture of my estimates of chemical composition are averages from several of the best analyses, the sources of which are noticed. A similar statement will apply to the other estimates here and there introduced. The calculati necessary for all have been carefully made and repeated- It is hoped that this procedure, — which, though it addfl to the labour and responsibilities of the teacher* afford the learner, results instead of processes ; selections of hap-hazard quotations ; and a general view, ingfo number of casual or conflicting detail-, — will be found as convenient to the reader, as it certainly seems to 1 student in the Lecture-room. The subjects of VOMITING and of T >u:ta i 3 been considered in an Appendix: as being collal the main purpose of the book. WILLIAM BBINT « 20, Brook Street, Grosvenor Square : May 8, 1861. CONTENTS. CHAPTER I. Tin: MEED OF FOOD. — BODILY WASTE. 0, physical and vital. — Idea of Nutrition. — Channels of Waste. — Chief Constituents of V Carbonic Acid, Water, Urea and it- Congeners, Salts, &c — S - t these Constituents respec- tively. — Numerical Summary.— Halations of Food and Waste to the Blood as well as to the Tissues. — Period of total Waste or Renovation of the Body. — Hybernation and Starvation as illustrating these State- ment- ....... Page 1 (HAP. II. Tin: NATURE OF food. — alimentary CONSTITUENTS. Definition of P 1. — Distinction from Drink. — Relation to other Ingeata. — Nature of Food. — Its Organic Source. — Hence Contrast and Rela- tions of the Animal and the Plant. — Cliemi.-al Relations of Food to the Body. —Its Variety essential — ZNIilk as a Model Food. — Constituents of Food. — Protein-compounds. — Fats, or Hydro-carbons. — Sugar and Starch, or Hydrates of Carbon. — Water. — Salts . . .39 chap. in. DIGESTION. ITS FIRST STAGE. Definition and Summary of the Process. — Mastication. — Insalivation. — Salivary Glands. — Their Structure. — Secretion. — Physical and Che- ; CONTESTS. mical Properties of Saliva. — Its Quantity. — Stimuli Flo v.-. — Its Action; mechanical, general, and special Functions. — Influx, various Sources, — Eelation to the Stomach an _ tition : in the Pharynx — in the (Esophagus — at the Cardia CHAP. IV. DIGESTION. THE STOMACH. The Stomach. — Its Shape, Size, Attachment, Situation. — It- Straetm — Serous Coat. — Muscular Coat. — M f this C Gastric Contents. — Pyloric Valv ■. — I — ticular Glands. — Matrix. — Ai S. — Lymphatics. — Digest i \ < * perties. — Chemical Proper! « — Action of Gastric Juice. — Pi Gastric Digestion . . . .88 chap. v. DIGESTION. THE SMALL lNIT>Ti: The Intestine. — Small Intestine. — Duodenum: its thn i — Mesentery. — Convolutions. — Jejunum. — Ileum. — Muscular C it — Its Movements; as deduced, observed. — Tin j. — Mucous Membrane. — Vo.lvuhe Connivente*. — Tul 60, — 1 1 • ii 3 or "Intestinal Juice." — Villi. — Their Constituents, including teals. — Their Changes during Digestion. — Absorption oi Fat — I cles; Agminate, Solitary. — Racemose Glands. — A - — Pancreas. — Its Structure. — Secretion or Pancreatic Jui — sical, Chemical, Properties. — Its Share in Digestion; or A ' Starch, (2) Fat, (3) Protein-compounds. — Liver. — It- Supplj — Its Physical Characters. — Its Structure ; Capsule, V — Is, i '..- Ducts. — Its two-fold Function. — The Bile. — Its Quant iv. flue-need by the Gall-bladder. — Its Composition. — Its two-mid I Bd Excretion, Resorption, — Its Influence on Digestion. — 1*- S m ea — Influence of the Liver on Digestion. — Contrast of Portal and Bloods. — Progress of Digestion in the Small Intestine CONTEXTS. XI CHAP. VI. DIGESTION. THE LARGE INTESTINE. Large Intestine ; its Measurements, Divisions. — Caecum ; its Shape, Stru c tur e, Openings. — Ileo-caecal Valve. — Vermiform Appendix. — Colon; its Form, Structure. — Its movements; observed, deduced. — Rectum; its Situation, Shape, Structure. — Its Sphincters. — Its Con- tractions; propulsive, expulsive or Defecation. — Its Folds. — Mucous Membrane. — Arteries of the Intestinal Canal; Superior, Inferior Me- senteric, and their Branches. — Intestinal Veins. — Rationale of the Intestinal Vessels* — Nerves of the Intestinal Canal. — Lymphatics. — Contents of the Large Intestine: Fsdcal, I -Digestion in this lent. — Office of the Cfecom. — Duration of Intestinal Digestion. — es. — Their Properties ; Sources. — Mechanical Ingredients. — Che- mical Composition. — Intestinal and gastri —Their Composition, Nature, and Sources. — Their Relation to Secretion. — Their Absorption. — Relation of Digestion to Nutrition. — Intermediate Circulation. — Digestion, its Expenditure of Force .... Page 199 (HAP. VII. yai:iktii:s OF food. — animal food. ; lients of Food. — Animal and Vegetable. — Their Mixture natural for Man. — Their Variation contingent — Nutritional Influence of Foods. — Contrast of Animal and Vegetable Food. — Varieties of Animal Food. — Meal or Flesh. Its Chemical Components. — 1. Fibrin. — 2. Albumen. — ■ ••latin. — Itl 5 I, — Nutritional Value of it, and of the Collagenic Tissues, — -1. I Its Nutritive Value, in Animal. Vegetable Food. — [ta Dig< stibility, as affected by its Kind, by Climate. — It^ Destiny, when assimilated in Excess. — o. Inorganic Con- stituents, contrasted with those of Blood. — 6. Secondary Organic Com- pounds. — Other Kinds *»f Animal Food. — Organic Muscle. — Heart. — Tongue. — Respiratory, Tendinous, Muscles. — Influence of Diseases, Age, Habits of Animal. — Flesh of Birds. — Fish. — Blood. — Brains. — Glands. — Bone. — EggS. — Milk. — Variations in different Animals as to Quality, Quantity. — Influence of Date of Lactation. — Physical Arrange- ment of Milk. — Cream. — Butter. — Its Components. — Its Nutritive Value. — Cheese. — Its Composition. — Its Varieties. — Its Nutritive Value . . . . . . . .246 Xll CONTENTS, CHAP. VIII. VARIETIES OF FOOD. VEGETABLE FOOD. Vegetable Food. — Its Characters. — Its importance to "National Life.— Value in warm Climates. — Its Variation* by Culta Climate, Age. — Cereal and allied Grains ; their VaJ their Growth, their Composition. — Pr>\ h A their Proteinous Constituent, Husk, Fat. Stare] tions in other Characters. — Pro- Chemical Changes. — Choice of Breads. — Leguminous Seeds. I mpo- sition. — Nutritive Value. — Potatoes. — Thei I ' Nu- tritive Value. — Roots and Fruit-. — Their Composition an Shoots, Leaves, &c. — Their Con ad Nutritive Prop*-: I chap. i\. I ONDIM Condiments, their Character. — Tl. ine. — Salt as illustrating these Relations. [ta to Scurvy. — Effed Use ; in Man, in Animals. — Acrid or Stunnls I I ts. Their with reference to Appetite. Circulation, Secretion.—. S] - — as Medicaments. — Complementary Natun Alliaceous Condiments. — Their Varietu - Condiments. — Oils. — Alkaloids. — C or Complementary Foods . . . . .331 CHAP. X. TEA AND OOFFEEi Tea and Coffee. — Their Introduction into Europe. — F- suits :' •' Use. — Their Contrast and Analogy ■ in Eff tfi Its Source. — Its Varieties (Black and Given V - — Composition of Tea. and of its Infusion. — Composition of fee, — Effect of Boasting. — Proximate Ingredients of its Decoction. — Nut: Value of Tea and Cofifee, — Physiological Effects. — Their Relation. — Theory of the economizing Action of Tea and Coffee. — contexts. xiii searches of Boecker and others hereon. — Resemblances, and Contrasts, of their Action. — Objections to such Views in general ; to these Experi- ments in particular. — Cocoa and its Preparations. — Their Contrast with Tea and Coffee. — Their dietetic Value . . . Page 344 CIIAP. XL ALCOHOLIC DRINKS. Alcoholic Drinks. — Their Relation to Food. — Their Classes. — Wine. — Its Typical Varieties. — Their Composition: as influenced by various Cir- cumstances. — Bordeaux and Burgundy. — Sherry, Madeira, Port. — Effer- dng Wines. — spirits. — Been or Ales. — Physiological Effects of Alcoholic Drinks. — Pathological Effects. — Action of Alcohol on the Functions. — On the Metamorphosis of the Body. — Researches of Boecker and others. — Objections to their Conclusions ; to their Facts. — Elimina- tion of Alcohol. — Its Influence on Vicarious Secretion. — Its Action on the Organism. — Its Influence on Bodily Temperature, — On Bodily, Mental Exertion. — Its Indirect Value. — Its Reaction, — Its Influence on Longevity, in Individual-, Populations. — Teetotalism. — Influence of Alcohol on Digestion ; on Ingestion. — Risks of Sudden Abstinence 365 CIIAP. XII. 00OKEBT. Importance ay. — Comparison of Paw and Cooked Flesh. — Di- •ve Import of the Changes wrought by Cookery. — Summary of its Advantages. — Process of roasting Meat — Process of boiling Meat. — Var; Boiling; their Objects, and Processes. — French Pot-au-feu as one of these Varieties. — Baking. — Stewing. — Soups. — Their Ob- jects, and corresponding Varieties, — Spanish Puckero. — Cookery of Flesh as affected by its Decomposition. — Economy of Cookery . 399 CIIAP. XIII. CHOICE OF FOOD, OR DIET. Diets ; as Mixtures of the preceding Articles of Food. — Difficulties of their Calculation. — Value of Physiological Chemistry in the Choice of Food. — Absolute Quantity of Food. — Results of Deficiency of Food. — XIV CONTEXTS. Test of a good Diet. — Uses of its Variety. — Office of Physiology in reference to Dietetics. — Chief Circumstances affed —Diet as modified by Age ; in Childhood, in Old Age. — Diet as modifii — By Habits of Life ; Confinement, Inaction. Mental Exertion. — By Climate; in Arctic, Tropical, Regions. — By B ice. — By !•- — Diet in Diseases of the Digestive Organs. — In Diseases ol El of Repletion. — Repletion; general and easoaL — Repletion from eh> Elimination ; from general Congestion. — Relation of Instinct * Diet in special Diseases, how appraised, — Fever; — Value of Alcohol in Disease. — Clue to it- Ofl 8, I A ferable Mode of its Administration. — Principle of the Choice of Food and Stimulants in acute Disease Appendix A. — Vomiting ..... Appendix B. — Dietaries ..... LIST OF VOOD-EXGRAVINGS. Fig. Page 1. Conglobate Gland of the Month ; after Koelliker . . 73 2. Diagram of two Ducts of a Lobule ; after Koelliker . . 74 3. Two V.-i- roglobate Gland j after Koelliker . . 75 4. Capillaries of a Lobule ; after Hyde Salter . . .79 5. Stomach inflated and dissected* to show its deeper Muscular Layers ........ 89 6. Fibre-cells of the Stomach . . . . .95 7. Section of the Pyloric Valve . . . . .97 8. Diagram to illustrate Peristalsis in a closed Tube . . 100 9. Diagram to show the Movement of the Food in the Stomach . 101 10. Vertical Section of the Stomach* showing its Structure . . 106 11. Upper part of a Stomach-tube, showing its dimorphous Cell- growth ....... 108 12. Arteries of the Stomach . . . . . .111 13. Vessels of the Gastric Mucous Membrane, as seen in a vertical Section . . . . . . .113 14. Superficial Capillaries of the Gastric Mucous Membrane . 114 15. Stomach and Intestinal Canal ..... 133 16. Bundle of Fibre-cells from the Muscular Coat of the Intestine . 137 17. Small Intestine prepared to show the Valvules Connivmtes . 144 18. Intestinal Tubes from the Jejunum .... 146 19. Superficial Capillaries of the Intestinal Mucous Membrane . 151 20. Vertical Section of the Jejunum, showing its Structure . . 152 21. Villus of the Jejunum during fasting . . . .153 22. Vessels of two Villi, injected ..... 155 23. Villi of the Calf, showing their Lacteals ; after Koelliker . 157 24. Villus prepared to show its Muscular Structure ; after Koelliker 158 25. Villi of the Dog, wrinkled by contraction . . . 161 XVI LIST OF ^VOOD ENGRAVINGS* Fig. 26. Similar Villi, showing the separation of their Epithelium and Body . . . 27. Villus of the Dog, during Digestion 28. Agminate Follicles ; after Koelliker 29. Agminate Follicles distended ; after Boehm 30. Portion of a duster of such Follicles 31. Section of Intestine showing an Agminate Follicle 32. Vessels of three Agminate Follicles of the Rabbit ; 33. Vertical Section of Duodenum, Bhowing aD 34. Diagram of two Duet- of a Lobule; the 2, . 35. Relations of the Duodenum and Fane 36. Under Surface of the Liver .... 37. Transverse Section of a Portal Canal : after Kieroan 38. Longitudinal Section of Sublobular Vein ; man 39. Longitudinal Section of a small Portal Canal: after Kiernau 40. Portal Venous Plexus; after Kiernau 41. Network of Hepatic Cells and I Koelliker ...... 42. Commencement of the Interlobular I 43. Large Entestine 44. Csecum, prepared to show the arrai 45. Viscera of the Male Pelvis, showing th< turn 46. Distribution of the Superior M Lrtery . 47. Distribution of the Inferior Mesenteric Artery 48. Branches of the Portal Vein .... Page 162 164 107 168 170 177 183 M 185 187 188 ox TOOD A^D ITS DIGESTION. CHAPTEB I. Till; NEED <)F FOOD. — BOJDIL1 WASTE. . physical and vital. — Idea of Nutrition. — Channels of Waste. — Chief Constituents of Waste, or Egesta: Carbonic Acid, Water, Urea and aers, Salts, flee. - Sources of these Constituents respectively. — Numerical Summary. — Relation of Food and Waste to the Blood as well BS t<» the Tissues. Period of total Waste or Renovation of the Body. — Hybernation and Starvation as Qlustrating these Statements. Is the animal economy, income is regulated by expendi- ture; and the ingestion of food replaces that loss of sub- stance which the body is continually undergoing. Even the hardest materials of the earth's surface are continually experiencing radual disintegration, as a result of the various physical processes to which they are exposed. Such processes may be instanced in the attrition and solution of solids, the evaporation of liquids, and the diffusion of gases. And hence, when we turn from these inorganic substances to the animal fabric, and consider its slight cohesion, the friction which its locomotion implies, its large watery constituent, and the feeble chemical affinities which enchain its elementary B 'J 2 THE NEED OF FOOD. atoms, we shall scarcely be surprised to find that the rapidity of its waste far exceeds that of the inanimate solids around us. But the rate of waste, and the consequent need replacement, both depend far less on simple physical causes of this kind, than on certain - which specific to the organised body. These actions, which, in the aggregate, make up what we term Lin:, do much imply, as actually consist in, a perpetual pr< flux and metamorphosis, which engages all of the body, and conducts their several through various successive phases of composition, t<» an effete and useless state, in which they arc finally i from the organism. Hence, whatever the share taken by the physi actions of diffusion, solution, friction, and evaporation, in the removal of the substance of the body, they in any sense the true causes of it- process of \ the real sources of its egeata or losses. They are but, it were, the janitors ot the animal fortress; the nal and amount of the matter- passing oat by those portali which they stand being always dictated by the big forces of the life that rules within. The growth of the young animal proves that its on the whole, outweigh its losses. And it is s reversal of this disparity which causes the aged animal to dwindle and decay towards the close ^ its allotted term of life. But in either case, the process o{ nutrition itself is far m affected than is the mere quantity of its materials, or of its products. Hence, in summing up the chief detaik BODILY WASTE. 3 that waste which forms one extremity of nutritional life, with a view to contrasting the indirect information thus gained with that more directly derivable from a study of food itself, we may conveniently restrict ourselves to that ideal or abstract view of nutrition which regards it as effecting the mere maintenance of the adult bod}'. And, while such a summary cannot well suggest any lively or definite ideas of this process without often referring to the quantities presumably concerned, these estimates must be received with an explicit acknowledgment that their inherent inexactness is increased by their ignoring many influential circumstances — age, sex, idiosyncrasy — without which they are quite inapplicable to the case of any individual.* The losses, or rrjesta, of the organism leave it by four channels. The excrement and the urine respectively con- vey away a moist solid mass, and a much greater bulk of a liquid containing a large proportion of dissolved solids. The skin, besides that gradual loss of substance from its surface which, under many circumstances, becomes perceptible to the naked eye, insensibly discharges vapours which arc easily augmented and aggregated into the liquid state of sweat. The lungs likewise discharge vapours and gases; of which the former are often seen to collect as drops of liquid upon neighbouring objects, while the latter may be recognised as carbonic acid and ammonia by the application of appropriate tests to the * Perhaps we may find the nearest approach to accuracy in supposing these estimates to refer to a healthy male, 35 years old, 5| feet high, and 10 stones in weight. B 2 4 THE XEED OF FOOD. air exhaled. Hence, any division of these solid, liquid, and gaseous, only regards their balkier constituent. As in the division of alimentary su into food and drink, all exact boundary fails as. feces are not only charged with liquids, hut mechani entangle, as well as dissolve, gases in their substance. urine, again, contains gases in a state of solution. Tin- lungs, beside exhaling volatile liquids, which are capabl condensing at a very moderate diminution of the pul- monary (105° F.) temperature, giv< I nailer quantities of liquids, and even of solids, which are dowb by ciliary movements ii]> the bronchial tubes that I the channels of exit for their expired tad vapours. Lastly, while various casualties may determine tin- \ \ or liquid form for the water which is given off bj skin, it may be questioned whether it- ammoii . acid, and even its fatty acids, _ 1 in these volatile or gaseous forms, <>v are thrown out the lowermost strata of the cutaneoofl tissues in a liquid (perhaps even in a solid) state. As the chief constituents of these losses, we maj enun rate carbonic acid, water, urea and it- congenero, i: _ salts, and sundry organic (and even d substances. The carbonic acid riven off from the body daily may be estimated at about '2 lbs.; a weight which, at ordin pressure and temperature, would correspond t-> a bulk about 17 cubic feet. Of this quantity, it IS Me that a single ounce, or halt a cubic foot, is all that finds it- \\a\ out by the skin: the remainder being exhaled from the lungs in the air expired, the carbonic acid of whiei BODILY WASTE. 5 about a hundred-fold more abundant than that of the inspiratory air (-04 and 4 per cent, respectively). The quantity of water daily set free seems to be about 6 lbs.* Of this rather less than half appears to be given off in the feces and urine (the latter containing about ten times as much as the former), and rather more than half by the skin and lungs. Of the latter moiety, again, the whole of which is often included under the term transpiration, the pulmonary share may be regarded as not more than 1 lb.; the skin furnishing the remaining 2 — 2\ lbs., usually in the form of watery vapour. These proportions fluctuate atly, as to require even than the usual qualifications of such estimates. The watery vapour exhaled may be regarded afl tending to satu- rate the inspired air, and therefore as vastly reduced by any previous approach to saturation in the surrounding atmosphere External warmth and active bodily exertion, which greatly t increase the water of the cutaneous secre- tion, correspondingly diminish that of the urine, and even of tie Urea and its congeners are justly regarded with extreme interest in respect to the quantitative aspect of nutrition. So small an amount of nitrogen is given off by the skin and lungs, whether pun- or in combination ( ammonia, and even by the intestinal evacuations (barely 3 per cent, of the daily loss of azote), that it is by this constituent * The weigh tfl mentioned are those most familiar to a medical reader : v. pounds avoirdupois; ounces, drachms, and grains of apothec; weight. t Valentin found the amount thus given off in a certain time to be quadrupled by active movemi B 3 6 THE NEED OF FOOD. of the urine, which contains nearly 50 per cent, of nitrogen, we may best measure both the waste of the azor and the quantity of azotised food necessary to replace it. About 480 grains, or 1 oz., would seem to be a tolerably exact estimate of the urea excreted daily by a healthy male adult. Eeducible to scarcely more than half this quantity for the female, and a quarter for the child or the aged person, and doubled, or halved, by diseases in which b waste exceeds (fever) and falls below (chronic heart disease) the standard respectively, it is equally amenable to two other sources of variation. Of these, one, fht natu- rally Be expected, is apparent rather than real, bei a diminution in the urea excreted from the body by a dis- eased kidney as is partly counterpoised by its alio* the quantity retained to accumulate in the poisoned Mood. In the other the diminution or incn quantity ifl emptied of its tents, so as to contain little more than serum, or even bo collapse at various points of its surface into an absolute contact of its membranous cell-walls, — we cannot hesitate to deduce, from the materials and products of combustion, and the evolution of heat, the actual occurrence of thifl BODILY WASTE, 11 process ; which, by whatever intermediate stages, evidently burns up the fat of the body into carbonic acid and water. The large proportion of fatty matter often taken in the food, together with the small proportion contained in the blood (which the greater part of the fatty aliment enters in the form of chyle), suggest that not only is fat slowly introduced into the stream of blood, but also that it is either rapidly consumed in the blood, or is soon set aside from it in the form of adipose tissue. Indeed, it is probable that both these alternatives obtain. Fur example, we may estimate that the whole mass of the blood contains not more than n } t - o th part of all the fat stored up in the aggregate adipose tissues of the body. Hence, apart* from the de- mands of the nervous tissues, —which, whatever the quan- tity of fat they claim, evidently imply such an elaboration of this material as is almost a guarantee for that slowness of their waste we shall hereafter deduce from other phenomena,— we might almost inter that, of the fat largely added to the blood by many kinds of food, a certain small proportion at once undergoefl combustion in this fluid, while all in i of this proportion is stored up as adi- pose tissue. Any further excess (which, by the way, would often be checked by the inability of the digestive* organs to receive it) seems to find an intermediate destiny ; a partial combustion in the shape of those oxidised fatty acids largely given off from the skin and lungs of certain animals, of Man in the Arctic regions, and of dogs when fed exclusively on fatty substances, f * Compare chap. v. f Compare p. 37. 12 THE NEED OF FOOD. But can we refer these products exclusively to such a source? Certainly not. For just as the most elementary facts of nutrition indicate that all the softer bodily tissue- undergo a process of waste, and especially that the mus- cular substance is rapidly destroyed and renewed inci- dentally to its own contractile function, so a mere* com- parison between the composition of the albuminous radicle of this tissue, and the urea which chiefly eliminates nitro- gen from the body, shows that any process which convert- albumen into urea must leave a large surplus of carbon and hydrogen, the ultimate destiny of which can only be accounted for by supposing their combustion to form part of the carbonic acid and water already alluded to. f Hence while the urea dismissed from the body must, u far as regards its nitrogen, be referred to tissues containing this element; and to the various azotised tissues, in pro- portion to the rate at which they severally waste whatever that rate may be; there is not one of these tissues, bo far as their composition is at present known, which does not also claim to be considered as a subject of that combustion of which carbonic acid and water are the final product-. How much, however, of these two products of combus- tion must be ascribed to the waste of albuminous tisfi and how much remains to be only attributed to that of the fatty tissues, cannot at present be decided. Still it may be interesting to conjecture an answer from two opp data. * Protein = (C 36 Ii 25 N 4 lc + 2 HO) = 2Urea {CJIJSfiJ + 8 HO + C M +H, . t A statement of which the fact, that exercise can for a time mainl the bodily heat against extreme cold, forms an illustration as old as th of hunting and of warfare. BODILY WASTE. 13 We may estimate, for instance, that the body of a healthy male contains about 40 lbs. of muscular substance, with a proportion of 18 per cent, of albumen and syntonin. Of this 40 lbs., with its 50,400 grains of protein, about -^-th would be lost daily during the process of starvation. These 840 grains may be corrected, let us suppose, to 900 or so, to allow for the waste of other albuminous tissues. But we shall find there are reasons for supposing that, of the 480 grains of urea found by Vogel and Xeubauer to be the daily out-going of this compound, about one half (or 240) must come directly or indirectly from the food, one half from the waste of the tissues. And this 240 grains of urea answers to about 800 grains of protein ; the remaining 550 grains of which, by combining with 1200 grains of oxygen, would furnish 1408 grains of carbonic acid and 342 grains of water. Again, the fatty matters of the body may be estimated to average about 32 lbs. in the healthy male adult, and may be regarded as losing about half a pound daily during inanition. In this half-pound, or 3500 grains of hydro-carbon, 27oo grains of carbon would combine with 7200 grains of oxygen to form 9900 grains of carbonic- acid ; and 405 grains of hydrogen would unite with 2880 grains of oxygen and with the 360 grains originally con- tained in the fat to form 3600 grains of water. The total quantities of carbonic acid and water of combustion derived from both tissues would thus be (1408 -f 9900 =) 11,308 and (342 + 3600 =) 3942 grains (l|and J-ths lb.) respectively ; quantities * which approach those deducible from the analyses of these egesta themselves already summed up. * See pp. 4, 10. H THE SEED OF FOOD. Of that steady, uniform efflux of urea which seems to represent the unavoidable waste of the system in the animal starved of all food, or of its azotised constituents, it is not difficult to conjecture the principal source. The muscular movements of that limited degree of locomotion inseparable from life; and especially the waste of those contractile tissues which, like the heart, the diaphragm, and the unstriped fibres of the vessels, of the bowels, and of the integuments, are kept in incessant action by the dema of the organic (as distinct from the animal) life, — tl are doubtless the chief sources of the urea which is dis- charged, independently of all reception of nitrogen into the body. In respect to the process by which una is constructed out of the various tissues, there seems little reason to doubt the general accuracy of the modern doctrine, that one or more of the intermediate stages of this metamorphosis are represented by the uric acid, kreatin, kreatinine, and other azotised alkaloids discovered by Liebig. And. as regards the albuminous compounds, we may find an analogous, i identical, stage of their change in some other constituents of muscle, which seem to represent the divergence, so to speak, of its non-azotised portions towards carbonic acid and water. Indeed, in the putrefaction of albumen. well as in the diseases of muscle, we meet with phenomena which may fairly suggest the conversion of some of its constituents into a fatty hydro-carbon as a contingent step in this metamorphosis. It may even be suspected. from some of the micro-chemical appearances of the fresh muscle, that, besides the adipose tissue between and BODILY WASTE. 15 amongst its elementary fibres, its sarcolemma encloses a fatty constituent, in quantity almost approaching that of the lactic acid and inosite also present here. The doubts thrown upon such a doctrine by the facility with which most of these supposed intermediate com- pounds are thrown out of the blood, unchanged, by the kidney, rest on a very slender foundation. Indeed, when we consider their variable amounts in different animals, — their remarkable variations in accordance with the nature and amount of the food, and even exercise, of the healthy individual, — and. finally, the ease with which many of the least powerful of those artificial reactions which the chemist has at his command partially convert them into urea and its allied substances, — we shall find it difficult to avoid the conclusion that they are really the later stages of a serial metamorphosis, the earlier and more indis- pensable steps of which are conducted in the blood and the tissues, leaving their last and all but perfected pro- ducts to be either carried to the full extent of the trans- formation into urea, or arrested, as regards a small but variable fraction of their total quantity, at some penul- timate stage of the corresponding metamorphosis. To which particular stage belongs the production of ammonia, — whether its production is preparatory to the formation of urea, or, in some sense, a protraction (and, as it were, supererogation) of the uric conversion of the azotised tissues, whose effete and poisonous residue it thus sets free in the self-diffusive form of an aeriform fluid, — is a question which no mere comparison of equivalents can answer, and to which physiology at present gives none but 16 THE XEED OF FOOD. an equivocal response. In like manner, many of the phenomena which accompany the abnormal presence of lactic acid, sugar, and oxalic acid in the urine, suggest for these non-azotised compounds an explanation, in reference to the combustible ingredients of the tissues, in close parallelism with the above allusions to the uric and hippuric acids, kreatin, kreatinine, &c. They seem, in short, to be intermediate stages of that combustion of which water and carbonic acid are the chief product-, and of which they constitute, both in their composition and reactions, almost the exact interval which Chemistry would, a 'priori, expect to find between the highly in- combustible mass of the animal body, and these terminal products of the oxidation of carbon and hydrogen, aa in all our artificial processes of combustion. Some idea of the chemical relations of these bodies may, however, be obtained from a contrast of their com- position; in which, for easier comprehension, they are represented without their basic water. Protein = C 36 Ho,X 4 10 + 2 HO : Gelatine . C 1S H 10 N 2 0. furnishing Non-azotised substances. Inosite (muscle-sugar) C 19 H ls O u Azotised substances. Kreatine . C 8 H^NgC^ Kreatinine C 8 H 7 N 3 a Inosinic acid C 10 H 6 N 2 10 Sarcosin . C 6 H 7 N~0 4 Glycin . C 4 H 5 N 4 Hippuric acid C 18 H 9 N 6 Uric acid . C 10 H 4 N 4 6 Urea . . C 2 H 4 N 2 2 Urea 1 eq. (C 2 H 4 N 2 2 ) + 2 eqs. water ^H 4 4 ) = 2 eqs. of carbonate of ammonia (2 NH 3 + 2 C0 2 ) Butyric acid Lactic acid Acetic acid Oxalic acid Carbonic acid Water . . . C a II- O a . C 4 II, 3 C 0. H BODILY WASTE. 17 The salts of the egesta remain in considerable obscurity > not only as regards their source and the mode of their construction, but even as regards their true nature and combination in the various excretory substances from which they are extracted by the chemist. That, on the whole, those which are most largely present in the blood and the tissues are also most largely and constantly cast out from them and from the body (as are the chloride of sodium and the phosphates); that the salts formed by various vege- table acids are converted into carbonates prior to the ex- pulsion ; that an addition to the food of large quantities of the salts ordinarily voided provokes a larger expulsion of those thus added ; that these saline egesta vary (as the phosphates in delirium and some brain diseases, the chloride of sodium in pneumonia), and remain uniform (as the sulphates during starvation), in circumstances for which we have no very complete explanations; — these, the chief facts as yet established respecting them, throw little light upon the nature and quantity of the various saline in- gredients required for the food of a healthy person. We may sum up our estimates of the daily bodily waste as follows : — Grains. Carbonic acid ...... 14,000 Water (8400 of \rhicli are formed by combustion) . . 42,000 Urea (including carbonate of ammonia 20 gra. ?) . . 480 Other organic constituents of the urine: namely, uric acid (8), kreatinin (7), kreatin (4|), lactic and hippuric acids (in- determinate), together about .... 20 ' by the skin 80 - {by tlie skm so ^ faeces 50 S urine 700 J 830 Total .... 57.330 C IS THE STEED OF FOOD. Hence, estimating from the researches of Valentin and others, that our typical man consumes about 14,570 grains of oxygen daily, the replacement of all his egesta would leave about 42,760 grains to be supplied by his food, minus those small quantities of water or oxygen which are absorbed through his skin. In other words, the main- tenance of the body requires about 6 lbs. of food and drink in the course of the twenty-four hours. Whatever the casual inaccuracies of these estimates, there can be little doubt of their substantial correctness, in so far as that they represent a large daily expenditure of bodily substance, such as can only be carried on in consequence of an equally large income of food. But it must, neverthe be recollected how wide is the interval between these two extremes of nutrition. And if, in attempting to bridge over this chasm, we go back from the egesta above mentioned, we light at once upon a question of extreme interest and importance in respect to nutrition generally, and to every detail of those states of health and disease which depend directly or indirectly upon it. The elaborated food enters the blood, to which its admixture may, indeed, be regarde the end and object of the whole digestive process. Hence it may be asked, " Do the metamorphoses which furnish the carbonic acid, water, and urea above specified, en_ the products of digestion immediately upon their arrival in the blood, or do they only affect the various tissues renewed or fed by these digestive products ? In other words, must the food poured into the blood make its way thence into the tissues, before it becomes effete in the sense of yielding the elements of the above egesta ? " BODILY WASTE. 19 The answer to this question can only be arrived at try the result of various considerations, suggested by the chemistry of nutrition, but too numerous and intricate to be fitly entered on here. But one or two of the leading phenomena may suffice to indicate the direction in which the truth probably lies. For example, there seems good reason to infer that the urea daily excreted by the starving animal is formed in the blood, and out of these various azotised compounds into which the proteinous mass of the muscular fibre becomes converted, as it is rendered effete by its own contractions. And if this urea is increased by increasing exercise — or even if (a fact more exactly, though not more conclusively, established) the una excreted in a healthy animal, is correspondingly increased by exercise, without any alteration in the quantity or quality of its daily food — the augmentation can only be ascribed to an augmented waste, chiefly engaging that contractile muscular substance on which this increase of exercise falls. But on the other hand, inasmuch as half the urea excreted in the human subject nourished by an average diet disappears during starvation, or during the exclusive use of non-azotised food, it may be inferred that this moiety is ordinarily derived from the azotised elements of the food. And a similar fact may be found in the contrast between the proportionate quan- tities of this compound habitually eliminated by Carnivora and Herbivora : the urea of the former being twice as copious as that of the latter, quite apart from the circumstances of exercise, bodily mass, &c. And just as an analysis of a meat diet, or of the peptone and other substances which are taken into the blood as its elaborated products, would fail C 2 20 THE XEED OF FOOD. to show either urea, or secondary and kindred compounds out of which urea might be directly produced, in sufficient quantity to account for the increased excretion of this sub- stance, so the suddenness with which a meal containing much flesh raises this excretion in exact coincidence with an increase of the other egesta (carbonic acid, &c.) con- firms the view that no intermediate conversion of such food into the muscular substance itself need necessarily take place. This view has the further advantages that while, on the one hand, it obviates all necessity for drawing that paradoxical contrast between the nutrition of the carnivo- rous and herbivorous animal (and even Man) which must otherwise be assumed, on the other hand, it gives to the waste of muscle in both classes that comparative uniformity, as well as that import to nutrition, which all the pheno- mena of this tissue seem to imply. We are, therefore, justified in inferring that the daily urea of a healthy man must be ascribed to two sources, part of it comes from the waste of his azotised tissues : and among these, especially of his muscular substance, from the kreatin and allied constituents which its syntonin and fibrin, form in proportion as they are rendered effete by muscular contraction or exercise, and discharged into his blood. Another part of it is derived from his food, and especially from the peptone which is taken up from the alimentary canal ; the constituents of which albuminous substance undergo a species of combustion in all the capil- laries : — a combustion which, distinct, it may be, in many organs from what is more specifically their function, every- where results in the evolution of heat, and in the forma- tion of urea, carbonic acid, and water. BODILY WASTE. 21 The same theory must doubtless be adopted as regards both those two sources — the alimentary and the corporeal — to which we have referred the two latter egesta. In very different proportions, the fatty and saccharine ingredients of the food and of the tissues meet, as it were, in the stream of blood, like the sources of urea. How much the fat stored up in the adipose tissue of a well-nourished person may be spared, or even added to, while that brought by digestion into his blood is being consumed ; how largely, again, the grape sugar similarly introduced may subserve an analo- gous, though somewhat different, combustion, and thus indirectly increase the general fatty contents of the body: — these are points which, though they involve for their de- cision an exactness which our existing knowledge of the quantitative chemistry of the blood noway admits of, are yet rich in important practical suggestions, not to be dismissed because incapable of unqualified reception. That the excre- tion of the above three compounds is inseparable from the maintenance of life; that the body alone can furnish them at its own expense : and that the food not only compensates, but partially supersedes this loss or waste of the tissues, at the same time that the blood itself is the seat of a pro- cess by which all surcharge of certain materials may be burnt up and cast out without previously permeating the tissues; — these are the lessons which, in a dietetic point of view, the chemistry of excretion seems best calculated to teach us. The ingestion of food may thus be regarded as fulfilling a two-fold purpose : on the one hand, replacing the wasted tissues ; on the other hand, diminishing or staving off their c 3 22 THE NEED OF FOOD. further waste by itself undergoing that combustion neces- sary both for the production of the animal heat, and for the throng of delicate chemical reactions which only the comparatively fixed and uniform temperature that pervades the organisms of the higher animals can fitly conditionate. And this two-fold office, which reconciles the other unintelligible discrepancies of the nutrition of many allied genera and species of animals habitually feeding on animal and vegetable substances respectively — without which we should have to assume that the muscular tissues of a slothful carnivorous quadruped waste three or four timi quickly as do those of the timid herbivorous creatures wl whole existence is almost one continuous act of locomol to escape his pursuit ; and that a vegetarian diet for the human subject, must, by lowering the rate vi' exchi which provides for the muscular function, pi nally reduce the vigour of this function itself— presents us with a remarkable safeguard against excess, in consonance with similar arrangements found in other stages of nutril The quickening spring which enters that fountain of to which we may fitly compare the rushing stream of blood, is prevented, as it were, from causing this stream to I down and overflow its banks, and so destroying the sur- rounding fields it is intended gently to irrigate, by a pro- vision which may be likened to the waste pipe of our cis- terns, carrying away all superfluity from the body by t excretory channels of which the carbonic acid, urea and water, of the lungs and kidneys, are the chief exponent.-. That food, indeed, need not necessarily go through the stage of living tissue before undergoing combustion and BODILY TTASTE. 23 elimination, seems scarcely less indicated by other facts, suggesting a parallel change in substances such as we can hardly imagine incorporated with the various structures, much less developed into them. The process which con- verts many of the organic salts of the alkalis into carbo- nates in the short interval between their ingestion and their reappearance in the urine, is one which, as regards its results, closely parallels the artificial combustion of the la- boratory; and can scarcely be attributed to any other change than a combustion like that which furnishes the carbonic acid of the habitual . But it would be difficult to specify any tissue of the body which tartaric or citric acid helps to build up ; just as, even assuming such a metamorphosis, it would be impossible to imagine pro- cesses of histological' formation and removal as instan- taneous as th<»se which the chemistry of excretion* shows this combustion to imply.* The rapid elimination of the gelatine of the food a< ureaf seems also to imply a change, equally removed from the tissues, and therefore located in the blood. It must, however, be remembered that, in regarding the blood as especially the seat of this combustive process, we are only indicating it as the antithesis, or rather the * The frequent influence of oxalic and "benzoic acids taken in the food, in causing the development of large quantities of these or kindred sub- stances, eliminated as such by the kidneys, would also be found, on con- sidering its rapidity and amount, equally adverse to this view of the exclusively histogeiietic import of the food, and favourable to the claims of the circulating blood, as at least one chief site of the chemistry of nutrition. f See the Chapter on Animal Food. C 4 24 THE NEED OF FOOD. complement, of the tissues themselves ; and that between these two hypothetic seats of the process — between the muscle, for example, on the one hand, and the adjacent capillaries on the other — intervene various fluids, inter- mediate in composition and office to both. The nutritional fluid which soaks the muscular fibre, and thus constitutes a 'pabulum from which the more solid parts of this fibre are derived (not to say deposited), gradually merges in composition as it approaches the capillary, from a specific muscular juice to a kind of dilute liquor sanguinis, proba- bly differing in little but its smaller proportions of albumen and fibrin from the true blood-liquor within the capillary wall. And, obscure and uncertain as is our knowledge of the details of the bodily combustion, we are likely to be nearest the truth in assuming that the microscopically close proximity, the intimate diffusion, and the immediate connection of these different liquids (as we may really term them) remits to all of them a share in the production of animal heat. The blood and the tissues may indeed be the theoretical extremes, or poles, of this process. But the nu- tritional fluid must, in strictness, be regarded as the chief or collective site of the decomposition this process implies. And a similar, though less important, office must be assigned to the serum which bathes the areolar tissues that are the ministers and companions of the muscular fibres in their contractile efforts. Such considerations may further suffice to show the impossibility of forming any even approximative esti- mate of the period during which the body is com- pletely renewed by an interchange of the whole of its BODILY WASTE. 25 substance. Not only, they would suggest, has every genus and species of animal its own peculiarities in this respect — peculiarities connected with its organisation gene- rally ; but even the individual, apart from the important qualifications of age and sex, is subject to similar, if less considerable, variations. And while, in contrasting the several tissues of the body with each other, we may trace the indications of an increasing rapidity of their waste and reconstruction, from a zero represented by such hard masses as enamel and bone to a large (though indeterminate) maximum in some of the softer (especially the muscular) tissues ; yet every detail of alimentation, both as to quantity and quality, seems to conditionate its corresponding modi- fication in the nutrition of all the organs. Furthermore, though all definite statement so utterly fails us, that the old view of a total renewal of the body every seven years may be regarded as scarcely less fabulous than the natural history of the Phoenix, still that comparison of the various tissues, which is all that can be attempted, is physiologically more accurate, as well as important. The particles of an adult bone move so slowly through their cycle of molecular life, that we can hardly say how long they may not last; indeed, it is their morphology which mainly decides* their renewal within, a few years. Cartilage, muscle, skin, and some other tissues, seem to have not only a shorter, but a more definite life ; bounded within limits which may be inferred from their phenomena of attrition, emaciation or enlarge- ment, and desquamation respectively. The relative dura- * The important histological details furnished by Messrs. Tomes and Do Morgan are here alluded to. 26 THE SEED OF FOOD. tion of the semi-liquid pulp of the nervous masses remains a mystery, and defies all calculation, chemical or otherwise : indeed, for aught we know, these structures may outlive, in this molecular sense, tissues such as might seem, in respect of their composition and structure, far more defiant of change; in respect of their office, far less active and energetic sources of those vital forces which in general, are only conditionated by rapid flux and decay. Valuable illustrations of these cursory statements re- specting food and waste may be found in certain conditi in which the specific course of the latter part of the nutri- tive process is observed, uncomplicated by variations in amount of ingest a. The hybernation of certain Mammal- is shown by I admirable researches of Valentin and others to be a kind of natural experiment on some of these details of nutrition. To avoid the protracted cold and hunger implied in their long winter, these animals are enabled to fall into a torpor; which, with brief intervals, lasts until the a spring again affords them the food and warmth they re- quire for active life. Plunged into a sleep far deeper than any ordinary slumber, to all appearance not only dr< but insensible — unwaked by irritation, or even by severe wounds — the Marmot can as little be regarded a as a sleeping animal, in the strict physiological sense of these words. A heart beating feebly about twice in the minute, and lungs which expand but slightly, and a" three or four times less frequently : such a reduction of these, the two chief functions of organic life, quite ex- plains the other phenomena of the hybernant state : — the BODILY WASTE. 27 lowered temperature ; the smaller quantity of carbonic acid excreted; and that diminished activity of nutrition in gene- ral, of which the diminished number of blood-corpuscles, and the arrested growth of hair and nails after cutting, are perhaps some of the most obvious indications. The numerical phenomena of nutrition during the hy- bernant state seem, so far as they are at present known, to be quite specific. That the daily relative loss of the tissues in general is but small, the length of time more or less occupied by this torpor might lead us a priori to expect. Their total loss is, however, sometimes little less than 40 per cent., a proportion quite as great as that which is generally attained in death by starvation. So little is sometimes lost from day to day, that the oxygen absorbed by the enfeebled respiration seems occasionally to turn the scale by converting this loss into a gain ; especially when the animal is surrounded by an atmosphere moist to satu- ration, and therefore incapable of taking up as vapour the water formed in the body. Further, it would seem that, though the hybernant creature is rather in the position of a cold-blooded animal, in the fact that its temperature is, within a certain limit, dictated by that of the surrounding medium, still its heat is sometimes greater than can be well accounted for by its diminished exhalation of carbonic acid. Perhaps, however, this peculiarity receives a sufficient expla- nation in the comparative waste of its tissues; the loss telling chiefly on its fat, severely on its (fatty?) skeleton, but little (barely one-sixth oftheir total mass) on its muscles,moderately on the liver, and least of all on its heart and nervous system. How greatly this economy of muscular substance is favoured 28 THE NEED OP FOOD. by the immobility of the torpid animal it is scarcely neces- sary to point out. But it is worth noticing that the com- bustion of fatty matter, as contrasted with that of muscle, would give off a much larger amount of heat, as well as a much larger proportion of water to carbonic acid.* Of the various diseases in which waste is maintained, or even exalted, concurrently with a diminution in the daily food, there is scarcely one at which we can profitably glance here ; most of them being complicated with peculia- rities, both physiological and pathological (if we may draw so doubtful a distinction), which prevent their affording any direct and important conclusions. Fever, consumption, diabetes, and certain conditions allied to the two latter maladies, are thus of little avail at present as illustrations of nutrition in the stricter sense of this word. Starvation in all its forms is perhaps scarcely more available as an illustration of the import of food, without a careful discrimination between these forms themselves. In death by thirst, the phenomena are mainly those of a poi- soning of the whole blood, resulting in a condition which somewhat resembles fever, and finally attacks the nervous centre with symptoms of delirium and coma. In death by what is, after all, the purest variety of starvation — the with- holdance of all alimentary matters, save only water — the symptoms and appearances are characteristic enough. But even here, many circumstances capable of modifying the results must be taken into account. The species, age. size, fatness, of the animal ; the degree of movement permitted * See foot-note to p. 33. BODILY WASTE. 29 or enforced upon it daring the period of starvation ; and the surrounding temperature ; are all capable of influencing the result. While it need hardly be said that any such more gradual process of the same kind, as destroys life by slowly decreasing the daily ingestion of all the alimentary princi- ples, instead of suddenly withdrawing them, would be far from answering to such a brief description of acute starva- tion as we shall now attempt. In acute starvation the feeling of hunger, which is in health the earliest and most natural signal of the require- ments of the system, gradually increases in severity to a | ravenous degree; a craving which, though not definable as pain, is in its way just as truly agony as the burning sen- sation which seems to crawl through every vein in fever, or the mortal suffering which is felt when the breath is checked in impending suffocation. As time goes on, this I craving seems to become less prominent, at any rate to be less distinguishable as hunger, merging into a feverous, and often delirious, condition ; the true import of which is, how- ever, often signalled by the fact that its illusions relate to the act of eating. Increasing debility of mind and body now conduct the sufferer to his death; from which neither the ingestion of food, nor all the aid Medicine can afford, have sometimes sufficed to rescue persons found in an advanced state of starvation. The capacities for diges- tion and assimilation seem, indeed, to be profoundly involved at a comparatively early stage of the process ; after which time restoration can scarcely be brought about, save by a skilful selection and adaptation of the food, both in quan- tity and quality, to the morbidly weakened powers of those 30 THE NEED OF FOOD. organs and secretions, by which alone its elaboration can be effected. The absolute date of death may be estimated as ranging from ten to twenty days, with a maximum of twenty-one (twenty-three?) days. The majority of cases would pro- bably be bounded by fourteen days ; indeed, unless under circumstances unusually favourable, both as regards pre- vious nutrition and the impossibility of all exertion (as in persons suddenly isolated from the outer world by a fall of earth in a pit or mine), this date is rarely exceeded. The amount of bodily substance lost before death cannot be better summed up than by the average proportion de- duced by Chossat for various animals ; namely, two-fifths of the healthy body. In the human subject perhaps this estimate is a trifle too large; just as, conversely, it seems scarcely equal to the waste of some of the smaller Mam- malia during starvation. A valuable insight into the details of this statement has, how T ever, been obtained from the toilsome and admirable researches of Bidder and Schmidt on animals: — researches which afford what is, in many respects, a more complete and accurate account of the chemistry (or rather the phy- siology) of starvation, than any mere observations on the human subject are ever likely to supply. Looking to the egesta, the daily urea drops in a day or two to about half of its previous amount ; and, diminishing but little during the next period, sinks to one-fifth, and then to one-tenth, in the two last d^js of life. The inorganic constituents given off, and among these especially the sulphuric and phosphoric acids, experience a BODILY WASTE. 31 somewhat similar, though less marked, reduction. Eapidly losing their associated salts, including their chlorides, they fall, in the first day or so, to an absolute amount of about one-half of their previous average ; from which proportion they gradually sink until shortly (18 — 24 hours) before death, when they dwindle to one-sixth or one-third. During much of this time, however, the decreasing weight of the whole body makes their proportionate amount a somewhat increased one. The * carbonic acid, as regards its absolute amount, gradually sinks to one-half its quantity before death. But as regards its proportion to the wasted body, it remains tolerably constant, increasing somewhat in the latter half of the period of inanition, to decrease slightly in the last two days. The water formed by combustion of the hydrogen of the tissues increases during the w T hole period; at first quickly, latterly more slowly. This increase, which is shown by the increasing amount of absorbed oxygen not applied to the formation of carbonic acid, corresponds to a rise from about 3 to 4. The absolute quantity of oxygen absorbed is continually a smaller one, sinking to about half by a decrease which is most rapid at the beginning and end of the process, but is pretty uniform in its middle. Relatively, however, to the altered bulk of the animal, or to the fraction of its tissues daily consumed, it is slowly increased, nearly from 3 to 4 ; only subsiding to its original amount in the last few hours of life. The watery vapour of expiration is diminished proportionally to the carbonic acid until shortly before death, when it 32 THE NEED OF FOOD. rises to a level below its original proportion. Lastly, the temperature of the animal only sinks in the last three days of life ; its excess of about 32° F. over the surrounding air sinking to about 21° before life becomes extinct. From examining the body of such an animal, and com- paring the amounts of its various tissues with those of another healthy animal reduced to the original weight of the starved one, it would seem that the different tissues and organs undergo very unequal degrees of waste. The process of inanition deprives the blood and fat of about 90 per cent, of their mass; the pancreas and salivary glands of 85 per cent. ; the muscles, liver, and spleen, of 60 to 70 ; the blood vessels, lungs, and intestines, of 25 ; the bones, it would appear, of part of their water only; and lastly, the nervous system, of a quantity inappreciably small. The absolute waste of course tells chiefly on the two chief tissues which divide between them the furnishing of those egesta above alluded to. The steady gradual diminution of the bodily weight is mainly the result of the waste of (1) the various albuminous tissu b, i" which the muscular mass may be regarded as the most important representative ; and (2 ) the nitty tissues. Of these the albu- minous tissues, both as regards their urea above mentioned, and the oxidisable residue left after subtracting this substance, show a waste which sinks to one-half in the first two days of inanition, then remains constant another week or so, at the end of which time it slowly sinks, to undergo a still more rapid decrease in the two last days of life. ^Yhile the fatty tissues daily oxidised seem to BODILY WASTE. 33 increase rather suddenly and largely on the first and second days, to diminish thereafter by nearly the same quantity daily from the beginning to the end of the process. Proportionally, indeed, to a given quantity of the bodily substance, the oxidation of fat seems to increase during the whole period of inanition up to nearly the last moment of life. In other words, the amount of fat consumed for each pound of the bodily weight has to the similar amount of wasted albuminous tissue a ratio which rises from 1 -6 on the first day of starvation, to nearly 3*1 on the last. Without attempting their detailed explanation, certain of the above facts may be illustrated by some simple considerations of a chemical character. The increase of carbonic acid and water of combustion is explained by the continually larger share taken by the fatty tissues in the waste of the body ; and by the larger proportions of oxidizable carbon and hydrogen which (as shown by the elementary * composition of fat) are derived from this substance, as contrasted with an equal quantity of albumen. The maintenance, or even increase, of bodily temperature, is similarly explained ; an equal weight of fatty matter giving off a larger amount of heat, or number of " units of temperature " than would albumen, f It is interesting * Thus fat (C 10 H 9 = 77), less one equivalent of water, would leave (C 10 H 8 = 68 or ff = ) 88*3 per cent, of its original mass in the form of carbon andjhydrogen for oxidation. While albumen (C 36 H 25 N 4 10 = 377), less two equivalents of urea(C 4 H 8 N 4 4 )andsixof water (H 6 6 ), leaves (C 32 K ±1 = 209 or §yy=) 53-84 per cent, of these elements. t Applying to the above data Dulong's estimates of the units of heat given out in the oxidation of carbon and hydrogen into carbonic acid and D 34 THE NEED OF FOOD. to compare the large consumption of muscular substance with its very moderate waste in the hybernant animal; the more so, that the contrast is noway explained by the comparative immobility of the latter, prolonged as its torpid state is during many months of perpetual car- diac and respiratory movement, with wakeful intervals of active, though brief, exercise. But, great as is the pro- portionate waste of muscle in starvation, it must be noticed that even this waste seems transcended by that of the blood ; which, however we may speak of it as albuminous in respect of mere composition, appears to be far more influential by its total or physiological import than by any such chemical character. Here again, assuming the total mass of blood to be adequately represented by it- corpuscles, there is a great contrast between starvation and hybernation : the losses of blood in the two fA being as 90 to 50 or 60 ; in other words, as three to two respectively. This brings us to the last point we need notice : the com- paratively sudden and equable manner in which both the waste of albuminous tissues, and the products of this waste, decline during the last few hours of life. Such a failure, evidently systematic and general — nay, pathologically speaking, pointing with no uncertain finger to the nervous system as its seat — is singularly contrasted with the unal- tered mass of the nervous tissues themselves, the corn- water respectively, wo may calculate that 100 grains of fat would set free 59520 such units against not more than 297*27 liberated by 100 g- of albumen. In other words, the combustion of fat liberates twice the heat given out by an equal weight of albumen. BODILY WASTE. 35 mencing involvement of which one might therefore almost fancy was the immediate cause of death. The fatty tissues of the body being burnt, the demands for these hydro- carbons begin to attack the nervous centre, and the citadel of life is at once vanquished by the paralysis of those in- dispensable cardiac and respiratory movements which it dictates and controls. Attractive and plausible as this theory is — nay, more, well as it serves to group together the facts — a further consideration of these facts would delay its adoption, if not suggest a preference for another view. A deeper involvement, and larger waste*, of the hybernant's fat does not attack its nervous system. And the steady maintenance of the quantity of fatty matter habitually consumed in the starving animal to the last day of its life, looks equally unlike that total failure in the supply of adipose tissue which is supposed to precede, and cause, the attack on the central and peripheric nervous masses. On the other hand, it is in the relative waste of the blood that we find the broadest (though, it must be owned, the least exactly established) contrast between starvation and hybernation. And while it is very sig- nificant to find the waste of the starved animal's blood far surpassing (as 90 to 60) that of its muscles, it is not less so to notice how vastly any great diminution of this fluid would affect the whole processes of waste ; as well as how directly and suddenly it might jeopardise, and indeed destroy, all those complex and delicate functions con- * According to the elaborate researches of Valentin, the fat of the Marmot is reduced to less than ^th of its original amount by the total winter sleep. D 2 36 THE NEED OF FOOD. ditionated, as we daily see, by its circulation through the nervous tissues themselves. But while it is probable that there are many variations in the phenomena of acute starvation, which would be revealed by larger inquiries like those alluded to; and while it is certain, both that the circumstances of the par- ticular animal always materially affect the results, and that the above details are scarcely applicable by mere transfer to the starvation of the very different and higher form of animal life exemplified by the human subject: it may be also pointed out, that there are other forms of starvation, scarcely less numerous than the casual circum- stances of this its typical variety, and merging into each other by gradations, such as sometimes render all exact distinction impossible. For example, we distinguish death by thirst from death by hunger, not only by its name and nature, but by its symptoms and appearances; from which latter we deduce that it falls with extreme and disproportionate severity on the circulation, and even (it may be suggested ) on those de- tails of the mechanism of this function which indispensably require a certain dilution or tenuity of the blood. indicated by some of the phenomena of Asiatic cholera. But however plausible such a view, we can hardly regard it as affording a sufficient explanation of the symptoms and result of a complete withholdanoe of watery fluid; the w r ant of which would be as necessarily fatal to the organ- ism, as that of any other alimentary principle. Nay, more ; the very same food which in one animal would inevitably bring about death by thirst, doc-, in another, BODILY WASTE. 37 permit life -and health to be maintained for an inde- finite period — in other words, contains sufficient mois- ture, and water of composition, to replace the total watery- expenditure of the creature's system. Hence there is no reason for distinguishing this kind of starvation, as re- gards its nature, from that producible by the deficiency of any other essential of the food. Indeed, we have seen that, even in the typical starvation, the state of the blood may perhaps dictate the fatal event, as it certainly does many of the symptoms of the process. In short, whatever the deficiencies of the food of an animal, let them only reach a given amount, and death must soon ensue. Must ensue, so far as regards the bodily expenditure we have summed up, if they fail to cover the daily losses of all its wasted substances : whether these be tissues like blood, or muscle, or fat; or ingredients like salts; or the larger, and no less essential, constituent of water. And while, as regards the time of death, and the proportion of the bodily mass lost before this event, the various classes of animals offer important differences ; and the degree of alimentary insufficiency, as well as the rate of its access, must influence both results, as shown by many * diseases ; still there is a close relation of the two, in all the higher Mammalia. The symptoms of inanition also somewhat resemble each other, however various their cause. Whether a dog be fed exclusively on white of egg, sugar, oil, or gelatine, the resulting symptoms of cachectia, though * The human body, which often loses a pound daily for many weeks to- gether in typhoid fever, may be reduced by more chronic diseases far below fths of its ordinary weight before these maladies, and after recovery. D 3 38 THE NEED OF FOOD. sometimes pointing to that particular ingredient of food which has been given in this unnatural isolation, closely resemble each other. Ulceration of the cornea, blind- ness, extreme debility, and emaciation, generally precede death ; though their degree, and the dates of their occur- rence, are liable to vary. And it would seem that more general starvation may, when chronic, illustrate the same rule, even in the human subject ; in whom similar ulceration of the eye, and dysenteric purging attended with intestinal lesion also of an ulcerative character, have frequently been noticed to precede the more constitutional mischief. Nor is it difficult to trace the germs of analogous phenomena in that peculiar poisoning of the blood which constitutes the disease known as scurvy. To these points, however, we shall incidentally return hereafter. 39 CHAP. IL THE NATURE OF FOOD. ALIMENTARY CONSTITUENTS. Definition of Food. — Distinction from Drink. — Belation to other Ingesta* — Nature of Food. — Its Organic Source. — Hence Contrast andKelations of the Animal and the Plant. — Chemical Relations of Food to the Body. — Its Variety essential. — Milk as a Model Food. — Constituents of Food. — Protein-compounds. — Fats, or Hydro-carbons. — Sugar and Starch, or Hydrates of Carbon. — Water. — Salts. A glance at the daily losses of the body has shown us the need of a large addition to its substance, in order to the replacement of that waste of its various tissues, which these losses represent. We have next to discuss the materials added for this purpose ; especially their quality and quantity: characters which we shall find are best described in their natural (though imperfectly known) relations to the same bodily waste, to which we have endeavoured to trace the losses they compensate. " What is food ? " in the ordinary sense of this word, is a question to which common experience suggests a sufficient answer : " The solid nourishment taken by the mouth into the body." That the word food, however, has a larger meaning, and one which more closely approximates to its physio- logical import, a moment's consideration would show us. D 4 40 THE NATURE OF FOOD. Thus, in regarding milk as the food of the infant, we modify the above definition by ignoring the conventional antithesis between food and drink. Indeed the shadowy character of the boundary between the two is well illus- trated by the facility with which the great Spanish casuist, Escobar, could reassert the rights of outraged nature ; and on the principle " liquidum non rumpit jejunum*' permit his devout co-religionists to fast on the very stiffest of chocolate, as being drink and not food. And a more physiological casuist could point to the temporary tenance of life by nutritious enemata, by baths, and by injections into a fistulous stomach or bowel, as further modifying the above dictum of common experience by -showing such an entry of food into the body as evades the mouth: or could perhaps instance asfo] transfuf of blood as defying even Escobar himself, with all the assistance he might derive from modern science, to decide whether or no the patient had been fed. Physiology, then, declines to distinguish between fo and v drink ; or rather, if it used the latter word at all, would limit it to distilled water, devoid of all dissolved solids. It thus declares the ordinary acceptation and use of ti terms to be, however convenient, scientifically inaccurate ; perhaps capable of generally indicating the consistence, but quite incapable of connoting the quality, of the matters they represent : nay, more, misrepresenting them, in so far as it suggests a distinction which has no existence, and alike overlooks the solids dissolved in all ordinary drinks, the water contained in all solid aliments, and the nourishment which we shall find even the purest FOOD AND DKINK. 41 distilled water must be allowed to impart, as w T ell as to mediate. The term drink, then, used in the physiological sense, is included in food ; used in the ordinary sense, implies it. And the only further question which therefore arises respecting the definition of food, concerns the extent which we must assign to it. Are all the ingesta of the body to be included under this head? Or, if not, to which of these ingesta shall we restrict it ? It is hardly necessary to point out that we cannot wrest the term from its ordinary acceptation to that wider meaning which would regard all the ingesta as food. Divisions are indispensable in all subjects, and may be convenient and useful— nay, substantially accurate — in spite of their being chargeable with inherent obscurities, or open to casuistic difficulties, and to verbal quibbles. For example : — that the very large proportion of oxygen daily absorbed ought not to rank as food, depends, not merely on the general necessity of distinguishing two such very different functions as respiration and digestion, but also on considerations referring to most of their details. For instance, it is doubtful whether any part of the oxygen taken into the body is ever directly built up into its substance, and certain that most of it appears merely to combine with the blood in a proportion which has a close relation with that of the other gaseous contents of this liquid — espe- cially of its carbonic acid. And though we have found reason to believe that a large proportion of the food absorbed also passes through the blood into the excretions without taking that deviation which would conduct it 42 THE NATURE OF FOOD. into the tissues, while it is obvious (comp. Chapter V.) that much of it passes directly through the alimentary canal without penetrating the organism at all, we may find a sufficient physiological distinction between food and air in the facts, that the food not only enters the body by a different channel, and through the instrumentality of very different processes, but that these circumstances, which would oblige us to make a distinction, and coin a word to express it, even were there none ready at hand, exactly concur with still more marked differences in the nature and form of the materials added to the body by digestion and respiration. We might easily correct the notion that a drink like broth was not food, by pointing to the solid contents, and nourishing effects, of this liquid. But it would be trifling with words to attempt to persuade any man, whether full or fasting, that the air he breathed was food, or that the water he had unconsciously absorbed in a bath belonged to the same category. Such unnatural ingenuity, the habitual exercise of which would destroy the use of all language, is fortunately checked by common sense; which, like the duchess who refused to accept the legal definition that denied her affinity to her own son, would probably decline to give up a substantia] result of experience to grasp at a pedantic shadow, or to regard the dog in JEsop's fable as having merely modified his diet when he let go the meat, and grasped a mouthful of oxygen. For any reasonable purpose, then, we may define the food as including all those substances which enter the alimentary canal from without the body, to be submitted FOOD ALWAYS OBGANIC. 43 to the digestive function. Fully conceding that, as respects the function of nutrition to which it ministers, its absorbed products may be aided and supplemented by cutaneous ab- sorption, just as we have seen it may be for awhile supplanted by absorption from the bodily tissues themselves — and that, unaided by respiration, it would not suffice to support life — there seems no reason to disturb the ordinary acceptation of the word, further than to give it that wider and more accurate meaning which allows it to include most drinks. Still limiting our attention to that aspect of nutrition which relates to the mere maintenance of the adult body, we shall find that it is the composition of its structures, and the rate of their wear and tear, that chiefly determine the kind of food it makes use of, and the quantity it consumes within a given space of time. And as regards the exact degree of this dependence, we shall find that here, as elsewhere, the operations of organised nature are only limited by wide general principles within which are apparently conceded great variety and fluctuation. The laws of nutrition are, so to speak, universal in their range, but elastic in their application. In respect to the nature of the food, we may first notice, that by far the larger part of it is always derived from the organic, and never from the inorganic, world. In other words, the chemistry of the organism has little power of construction or synthesis. So that, although a proximate analysis of the tissues of the animal body presents us with compounds which may be shown to consist chiefly of a few elementary substances united to each other in varying pro- portions, still the uncombined carbon, oxygen, hydrogen, 44 THE NATURE OF FOOD. and nitrogen, which, may surround or penetrate the living animal, are never directly built up into these tissues. On the contrary, the various substances which form the proxi- mate principles of the several structures of the organism are themselves produced by the metamorphosis of kindred compounds introduced in the food: — compounds which have been in their turn derived from the vegetable king- dom; either directly, in the shape of plants, or indirectly, from substances constructed out of vegetable tissues by the organism of another animal. And the inorganic substances introduced as such into the body seem almost restricted to the subordinate (though equally indispensable) office of combining with these products of vegetable life, and modi- fying their actions in obedience to the necessities of the animal. In what form they are present in its tissues we know not. But while it is certain that the combinations actually existing here dming life are often very different from those we find in analysing the dead tissues— and | - sible that a single element of these inorganic dubstana sometimes combined directly with all the other iii_ dients of the tissue — we may sum up their general value under the two aspects of, (1) the chemical composition which they complete, and (2) the vital flux which <; direct or indirect result of this composition") they heli< conditionate. The above statement as to the organic nature of the food suggests some interesting considerations. In the first place, it seems to show that the living animal of to-day pre-supposes another organisation o{ yesterday : — that its individual descent from two creatures of the same PLANT AND ANIMAL CONTRASTED. 45 species is accompanied by a less evident, but quite as real, transmission of substance from several previous beings. In short, that the greater part of its entire mass might be regarded as the sum of various legacies, which have been bequeathed to the existing organism by the various plants and animals that lived before it. In the next place, it indicates a fixed and definite rela- tion between the plant and the animal. The former is thus the chief agent in the constructive chemistry of the latter : — a necessary link in that chain of processes which builds up organic principles out of the elements of inor- ganic nature, or out of those simpler products into which the particles of the animal body are finally converted by its waste during life, and its putrefaction after death. The carbonic acid given off by the living or dead animal may especially exemplify the latter remark ; converted as it is by the vegetable from a poisonous gas into various sub- stances which are in the highest sense alimentary, and essential to the life of the animal. Such a relation perhaps justifies an attempt to contrast the food and the digestive process of these two forms of life. In the animal a highly azotised composition is connected with — and probably essential to — an active life ; which, in its turn, implies a rapid waste of substance. On the other hand, the plant lives slowly, wastes little, and contains but a small quantity of azotised material. The food of each appears to correspond with these re- quirements. That of the plant is, in great part, inorganic ; consisting mainly of compounds which pervade the soil that surrounds its roots, or the air which bathes its leaves. 46 THE NATURE OF FOOD. While that of the animal is organic; that is, the sub- stances which compose it are the products of a previous organisation. The elaboration of the food repeats the preceding con- trast. The plant builds up inorganic into organic matter : — a process of chemical synthesis, which may well be effected with great difficulty, and by slow stages. While the animal scarcely does more than convert one proximate principle into another ; — a metamorphosis which involves no change of composition, and the facility of which is but partially counterbalanced by its requisite rapidity and amount, and the delicacy of its adjustments. The agents of these processes are also susceptible of contrast. For in the vegetable they appear to be more dependent upon external forces, such as li_ r lit. heat) and electricity. While, in the animal, they Beem more depen- dent upon causes inherent to the organism.* And in both, the site of the elaboration or change in the food corresponds to those situations where the above agents are most readily applicable: — viz., in the plant, to the leaves and other green parts of its surface: in the animal, to a cavity in its interior. The presence of such a cavity not only permits the less frequent application of nutritious substance to be compensated by the ingestion of large quantities at particular times ; but, while it thus meets the peculiar requirements of an animal organism, also allo¥ that locomotion which is so necessary to the mere prehen- * Traces of this contrast between the animal and plant during be found in those processes of putrefaction and " ereinaeausis " whii tively effect their dissolution after death. PLANT AND ANIMAL COXTKASTED. 47 si on and selection of its scarcer food. Its subjection to volition renders ingestion a work of rapid and powerful mechanical force, in place of a slow physical imbibition. And finally, the same internal situation which directly sub- jects its contents to the agents of the digestive metamor- phosis, also isolates them from all surrounding objects, besides favouring the temperature often necessary to the operation.* Doubtless such a contrast ignores many important re- semblances between the two. For example, there are traces in the plant of a process of waste, which evolves heat, gives out carbonic acid, absorbs oxygen, and thus suggests an oxi- dation like that ascribable to the tissues of the animal body. Further, we are ignorant of the exact share taken by the more elaborate organic ingredients of the humus in the nutrition of most plants, or how closely some of these ingredients approach the secondary organic compounds derivable from the protein group. On the other hand, the conjecture that some of these very compounds may aid the nutrition of the animal, becomes continually stronger as we pass down the scale from the great scavengers of * Hence, instead of a digestion corresponding to that of the animal, the plant presents us with a process in which mere reception is so predomi- nant, and elaboration so diffuse, and so subversive of all the previous pro- perties of the food, that we might almost compare it with the absorption of the chyme and chyle into the blood. As a kind of fanciful corollary to this, vre might regard the crust of the earth, and the atmosphere which surroundj it, as forming a common stomach or receptacle of food for the whole vege- table kingdom. For they include or receive, detain, and give up the chemical food of the plant ; in quantities which, though ordinarily suffi- cient, are capable of being locally exhausted by the excessive demands of particular species or genera, and renewed by an artificial supply. 48 THE NATURE OF FOOD. the Bird and Eeptile classes to the humbler Invertebrata : many of whom evidently turn back toward the animal kingdom various matters just about to leave it by further decomposition, and fix them in their own bodies. Still the contrast remains useful and even accurate ; so that, for example, we know of no animal which is nourished by the carbonic acid and ammonia so largely applied to the ma- terials of the vegetable tissue. Lastly, since animal and vegetable life are thus alike complementary to each other, in their broader features and their minuter details, we may conjecture that, in the pre- sent disposition of our planet, they form what is almost a constant magnitude : — a sum of organised life, the amount of which is subject to but slight variations from one time to another. Nay more, we may almost suspect that the total of animal existence — ■ the materials of which range thus regularly through vegetable organisation as an essen- tial part of their cycle of metamorphosis — is in the main equally constant and fixed. Created by what even modern science must be content to own as a miracle, in the strictest sense of the word, it seems not improbable that the collec- tive outlines of animal and vegetable Life are dictated by some vast law of this kind. According to such a law, each by each, and both together, would make up certain con- stant units ; the innumerable constituent fractions of which might vary within vast limits, without exercising any effect on their respective sums. And thus the world of Life around us would only parallel that perpetual flux, but un- altered quantity, which the chemist has long predicated of the various elements that compose the globe we inhabit. CHEMISTRY OF NUTRITION. 49 But if, on the one hand, the animal is incapable of con- structing its complex tissues from the simple elements of inorganic nature, still, on the other hand, it is not bound down by such rigorous chemical necessities, as to demand a food possessing an exact identity of composition with itself. A large proportion of the animal creation feed on a veget- able diet, the constituents of which deviate considerably from those of their own mass. And but very few of even the more carnivorous animals are in the habit of devouring their own species. Finally, though blood forms the pabu- lum of all the animal tissues, and hence closely approaches their total composition, still it does not appear to form even an advantageous article of food, far less an indispen- sable one. And while such considerations may suffice to show, that there is no true identity between the food and the tissues in general, the progress of modern physiological chemistry plainly indicates, that an identity of this kind would be equally impossible in detail. Thus it is not improbable, that the tissues of every individual possess chemical pecu- liarities more or less specific to himself. And it is all but certain, that the various proximate principles isolated by the chemist are not definite combinations of certain ele- ments in equivalent proportions — as are the salts, acids, and alkalis of the inorganic world — but rather ever- varying mixtures. Those various forms of protein which it is so convenient to distinguish by the names of albumen, fibrin, and casein, may indeed be separated from the tissues of animals, and even of vegetables, by the same rough processes ; and may therefore respectively exhibit a close 50 THE NATURE OF FOOD. resemblance in their composition and properties. But an accurate analysis would probably show, that the organic substance represented by either of these terms is never precisely identical in any two specimens. It is the total of a number of constituents, the result of a variety of pro- cesses, the end of a serial metamorphosis : — rather than a definite and specific compound of carbon, oxygen, hydro- gen, and nitrogen, with exact (though minute) quantities of salts or their bases. And not only is there no identity in the composition of the organism and the ingesta, but it would seem that there are some tissues of the body which have no constant representative in the food : no kindred substance to wl their formation can always be referred. Such are various tissues thai yield gelatine ; a substance which. though it appears largely to escape assimilation when in- troduced into the organism from without, is yet constantly formed within it, from metamorphoses of other parts i substance. (Compare Chapter VI. ) The chemistry of nutrition therefore implies neither construction, on the one hand, nor identity, on the otl but something midway between these two extreme s. [tfl forces occupy, so to speak, a debatable ground bet* the prehension of old materials, and the formation of new ones. And the food submitted to its action is only re- quired to pogsesfi such a similarity of composition with body, as will concede these limited changes, without imply- ing any wider range of metamorphosis. An exact definition of the degree oi resemblance tl requisite, would be foreign to our present object. Ind< CHEMISTRY OF NUTRITIOX. 51 in the existing state of our knowledge, it is impossible to offer any correct and comprehensive view of the nature of those metamorphoses, which accompany the digestive act, and are bounded by the food and the organism as their beginning and end respectively. It is enough to indicate, that they appear to be intermediate between the forces of chemical affinity on the one hand, and homogeneous and heterogeneous adhesion on the other ; and that while they are sometimes * akin to the formation of hydrates, they occasionally resemble those still more recondite phenomena which are concerned in the production of isomeric or iso- morphous compounds : — substances which, though identical in their composition, offer striking differences in their solubility, as well as in many of their chemical properties and reactions. Such a very limited convertibility of the main compo- nents of the food, renders their variety almost as essential, as though each different tissue of the body had required the entry of its corresponding substance from without. In other words, within the range of that chemical parallelism just sketched out, the organism demands alimentary com- pounds containing all the different ingredients necessary to cover its own waste. This fact receives a good illustration from that selection which the instinct of most persons would impel them to make. Left to himself, Man always chooses a mixed diet, composed of proper quantities of animal and vegetable, of liquid and solid, matters. Nay more, that almost equally imperious instinct which urges him to vary his * Compare the remarks on the gastric juice in Chapter TV, E 2 52 THE NATURE OF FOOD. diet, is, though often confounded with the morbid cravings of luxury, essentially nothing less than an expression of the natural wants of a healthy organism. Obscured, however, as these really natural instincts often are by the stereotyped tastes and habits of highly artificial states of society, we gain a far better insight into the proper composition of food, by examining that store of nutriment which, in the shape of the yolk of the Bird's egg, or the milk of the Mammal, Nature herself provides for the maintenance of the young of these classes. Of these two substances, the milk is justly regarded as forming the very best example of a proper food : — both as regards the nature of its several ingredients, and the proportion- in which they are mingled with each other. Milk. — The alimentary properties of the milk are due to the presence of a number of proximate constituents, the more important of which may be enumerated as follow-. — (1) A protein-compound, casein; (2) a hydro-carbon or fat; (3) a hydrate of carbon or sugar; (4) certain salts: and (5) the water in which the whole of these materials are suspended or dissolved. Of these five groups of sub- stances, at least four are indispensable ingredients of every proper food. The hydrate of carbon and the hydro-carbon are, to some extent, capable of forming substitutes for each other. But with this partial exception (an explanation of which will be attempted by and by), the absence of any one of these constituents, or even its presence in insuffi- cient quantity, suffices to destroy the capacity of any par- ticular food for maintaining life : so that an animal limited to such a diet ultimately dies with appearances of inanition. ALIMENTARY CONSTITUENTS. 53 And a fortiori, the ingestion of but one of these alimen- tary ingredients, — such as albumen, fat, or sugar, — is soon attended with effects which still more closely resemble those of starvation. Such a diet does indeed essentially starve the entire organism, even while it supplies some of the constituents of its lost substance. For although the unchecked waste of the remaining constituents of its mass tells upon certain of its textures with greater rapidity and energy than on others, still it ultimately involves the whole in a common destruction : — a fact which need little surprise us, when we recollect the mixed composition of the simplest tissues, and the intimate mutual dependence of the most distant and isolated parts of the body. Constituents of food. — 1. Protein. — The first group, consisting of what are called the protein-compounds, in- cludes a number of proximate principles, which are de- rived from both the animal and vegetable kingdoms of nature. The chief of these principles are albumen, fibrin, and casein. By digestion in solution of potash, and pre- cipitation with an acid, either of these yields a substance called pmotein: — a name that alludes to the relation this principle is supposed to bear to all the compounds from which it is thus obtained. It is regarded as their common starting-point (irproTEvco^ primas partes teneo), and most essential component. And the slight differences of com- position offered by each particular protein-compound, are explained as chiefly due to variations in the nature and amount of certain collateral ingredients, the addition of which to protein imparts the specific characters of albu- men, fibrin, or the like. Hence the various protein- com- E 3 54 THE NATURE OF FOOD. pounds are supposed to differ, not so much in elementary composition, as in certain characters which might almost be termed morphological : — namely, outward form, physi- cal properties, degree of solubility, and the like. Such a view of the nature of protein is doubtless open to many objections. But without entering on an elaborate discussion of these, it may be suggested that the term " protein " is almost indispensable for purposes of descrip- tion. That certain substances are closely related in com- position to each other ; and that they yield, to such and such treatment, an^analogous (if not identical) substance : — this is all which we can affirm, or need accept* with req to the disputed chemistry of protein. And bo long accept such a doctrine with the cautions implied h< re and elsewhere, it is difficult to sec what disadvantag follow from its use. The less so, that some term mu necessity be adopted to express wh - to be, ch cally as well as logically, the gi nti8 of the Bevera] constituted by albumen, fibrin, casein, &C; The exact process by which one of these bo called protein- compounds undergoes conversion into another is still a complete mystery. But that such cha nstantly obtain in the living organism, cannot be doubted. hence, while the quantity of albumen in the animal fa and the constancy with which it is present, ap- proximate principle the leading position in the al group of proteinous substances, it is on its generic, and not on its specific, properties that our attention ought chiefly to be fixed. The protein of the food may be regarded as its ALIMENTARY CONSTITUENTS. 55 essential constituent. The reason why such an importance is ascribed to it becomes sufficiently evident, when we compare its composition with that of the body which it is intended to nourish. The highly azotised constitution it possesses (C 547 +H6-8 + N 14-2 + 24-3 = 100) closely approaches that of the solids of the organism gene- rally. And it shows an equally important relation to most of the tissues in detail. It forms a large constituent of the blood ; and therefore of the plastic nutritional fluid which exsudes directly from this fluid. It is the main com- ponent of the muscles which execute the various move- ments of the body. It is an equally important ingredient in the tissues of both the central and peripheric parts of the nervous system. It is probably the source of the gelatinous * tissues ; which, in the herbivorous animal, can only be derived from a kind of degradation or regressive metamorphosis of its albuminous substances. And, finally, its large amount in the structures of the foetus proves that it is just as important to the evolution and growth of the animal, as it is to its maintenance. In short, in protein and its various kindred substances, we recognise a prox- imate principle, which is essential to all the structures and functions, forms the predominant solid ingredient of many .of the tissues; and is, in one word, the chief substantive agent of the chemistry of Life. The quantity of protein necessary for the proper main- * Ignorant as we are, both of the nature of this metamorphosis, and of the various stages through which it is conducted, there are reasons for con- jecturing that the formation of the chondrin radicle generally precedes that of the substance (" collagen ") which yields gelatine by boiling, E 4 56 THE NATURE OF FOOD. tenance of the healthy animal can only be estimated from indirect and approximate calculations. In human milk, the albuminous compounds are chiefly represented by casein, which forms about 3J per cent, of its total quantity. But we can scarcely guess how much milk is daily consumed by the sacking animal, or what proportion this amount bears to the weight of its whole body. And we are justified in assuming, that a large fraction of the protein thus introduced into the system, is applied to exigencies of growth and development which have little or no place in the adult animal. Assuming an exact maintenance of the adult organism, without increase or decrease, we might expect that an examination of its various azotised excretions would teach us how much nitrogen had been discharged from the system within a given time : and hence that, by comparing this quantity with the known elementary composition of protein, we might be enabled to calculate how large a quantity of the azotised constituent of the food ought to be added to the system, in order to replace its daily loss. But here we are met by a difficulty connected with the process of nutrition itself: with that chain of events of which food and waste constitute only the extreme links. The amount of nitrogen given off by the body does not depend solely upon the quantity excreted by its waste, but also varies in close correspondence with the quantity taken in its food. It is therefore greater in carniver and less in herbivorous, animals. Hence the true or essential waste of the organism, in ALIMENTARY CONSTITUENTS. 57 respect of this constituent, can only be determined from an analysis of the excretions of animals which have been kept for a day or two, either without food, or on a diet altogether devoid of nitrogen. In both cases the results are the same. The nitrogen of the egesta drops to a certain minimum ; at which it remains for a considerable period. The quantity of nitrogen evolved by the lungs and skin is at any rate so small, as scarcely to form an important element of calculation. And even the larger quantity excreted in the biliary resin, hardly deserves notice. It is in the uric acid, and above all in the urea, of the renal secretion, that this element is chiefly dismissed from the body as an effete compound. And hence it is from the urea found in such experiments that we may best deduce the probable rate of daily waste in the albuminous tissues ; and the corresponding quantity of protein which therefore has to be supplied in the daily food.* From observations of this kind on the human subject, we may infer that, in Man, the albuminous substances of the adult organism undergo a necessary loss of about If ounces daily ; — a quantity which corresponds to scarcely more than yy^th of the weight of the body. While if we suppose that a new-born infant, weighing six or seven pounds, consumes daily about ten or twelve ounces of milk, containing 3^ per cent, of casein, the quantity of protein thus introduced into its alimentary canal would amount to the much larger proportion of about -2^-5 th of its total bodily mass. * Compare pp. 13, 19. 58 THE NATURE OF FOOD. The larger proportion of albumen thus consumed by the infant probably depends upon at least two causes. As a smaller * animal, it is subject to a more energetic waste of substance. And as a growing animal, it not only lays aside in its body a constant surplus of its income over its waste ; but possibly undergoes a more active metamorphosis, which still further increases the proportion of its effete materials. But, apart from the influence of age or size, there is no doubt that a careful comparison of the azotised ingesta and er/esta would always show a marked disproportion between the two. There are indeed obvious reason.--, why the nitrogenous constituent of any suitable food should always greatly exceed that quantity which is required by the strict exigencies of the organism. A considerable proportion of the casein contained in the milk taken by the sucking-child, is often found to through the alimentary canal without being absorbed into the blood. And in the case of many other varieties of food, the insoluble state of the protein-compounds actually present f affords a still greater obstacle to their absorption. * From researches by Frerichs, Lehmann. Bidder. Schmidt. Boussing Valentin, and others, we may estimate the normal daily waste of albu- minous compounds, relatively to the whole body, in the undermentioned animals, as follows : — Mouse, ^th ; Rabbit, y^th ; Cat. jf^th ; Dog, ^th ; INIan (as above )~- 5 ^th ; Horse, y^tli. •f It is thus that I should explain the above estimate of the proportionate waste of the albuminous substances of the Horse ; an estimate founded, to the best of my recollection, solely on the proteinosis ingredients of its daily food, as calculated by Boussingault. It can hardly be doubted that a I proportion of these constituents, as they exist in hay. or even in corn, I be so far insoluble as to escape digestion, and escape in the excrement. Hence it is possible that the above fraction ought to be - A for ALIMENTARY CONSTITUENTS. 59 In a proper mixed diet, however, we may detect some approximation between the presumable gain and loss. Thus the daily rations * of the British soldier on home service include little more than five ounces of albuminous substance ; — a quantity which is therefore about thrice the amount of this material, which the necessary waste of his body probably dismisses from his system within the same period of time. 2. The next group of alimentary substances is that of the fats, the composition of which has led to their re- ceiving the generic name of hydro-carbons. They are found in both animal and vegetable food. In the milk, they are represented by its butter ; the proportion of which in human milk, amounts on an average to about 3 J per cent. The great variety of different alimentary substances of this kind is such as to preclude even their enumeration. The most important are stearin, elain, and margarin. The composition of these three fats may be generally stated as almost corresponding to the chemical equivalents of carbon and hydrogen ; or, more exactly, to ten atoms of each of these elements, minus one of hydrogen, and plus one of oxygen (C 10 H 9 0; or C 79 + H 11 "4 + 9-6 = 100). The uses sustained in the organism by these fatty consti- tuents of the food are easily indicated as respects their larger and more general relations, difficult as it may be to follow one (e, g. -^^ to ^q), in closer accordance with the above law relative to the bulk of the animal, * See Appendix* 60 THE NATUEE OF FOOD. them into all their details. Thus, the fat of the body, which is arranged as a thick layer (j/anniculus adiposus) placed immediately beneath the skin and on the muscles, also involves the various groups of muscles, as well as some of the more important viscera, in special coverings of adipose tissue ; coverings which, by their properties as bad con- ductors of heat, materially aid in preserving the uniform and warm temperature essential to the functions of the higher animals. Equally obvious is the protection the adipose tissue affords to the mechanical integrity of many external and internal structures ; which, as in the case of the breast and the kidney, are thus surrounded by millions of tough elastic sacs filled with oily liquid — of oil cushi (so to speak) imbedded in areolar tissue. Both of these purposes might doubtless be accomplished without in- volving any rapid waste and replacement of the fatty materials themselves. But the vast quantity of fatty matter which enters into the composition of the nervous system, and the primary importance of this delicate and energetic or^an to the maintenance of life, entitle ua infer, that its functions imply such a metamorphose its substance, as can only be sustained by the continual supply of new materials to replace those rendered effete. Nor is it improbable that the delicacy of these metamor- phoses so far transcends their amount, as that fatty sub- stances may be converted by them into compounds really effete for the nervous centres, though still retaining sufficient of their original fatty composition to subs* the lower purposes of adipose tissue in the system large. The numerical phenomena of nutrition further ALIMENTAKY CONSTITUENTS. 61 show, that the process of respiration is constantly dismissing from the body an amount of carbonic acid, the proportion of which to the azotised egesta proves that it must have been derived more or less directly from an oxidation of the fatty, as well as of the albuminous, tissues. The quantity of fatty matter contained in the healthy organism strongly confirms all these views; and thus helps to account for its dietetic importance. For, in- cluding all their varieties in the tissues just alluded to, we can hardly estimate the total hydro-carbons of the human body at less than ^th or ^-th of its weight. And since they scarcely form -s^-th part of the blood, it follows, that even assuming the total quantity of this nutrient fluid to equal -^th of the corporeal weight, its fatty constituents amount to little more than -3-50-th or Q-i-Q-th of the various fats which are deposited in the central and peripheric structures of the nervous system, and are stored up in the adipose cells of other parts of the body. Such an estimate further entitles us to con- jecture, not only that the fat taken up at any one time by the digestive organs is limited to a very small quantity ; but also, that it either undergoes some important meta- morphoses before reaching the general mass of the blood, or is very rapidly eliminated from this fluid.* 3. The hydrates of carbon form a class of nutritional substances, the elementary composition of which is still more exactly indicated by their name. In other words, they consist of carbon, united with hydrogen and oxygen in those equivalent proportions of these two latter elements * Compare p. 1 1. 62 THE NATURE OF FOOD. which are necessary for the formation of water (C 12 H ]2 12 ). This group is a very large one : and includes, not only the various forms of cane, grape, and milk sugar, but a number of kindred substances ; — such as dextrin, gum, cellulose, inosit, and, especially, starch. All of these organic principles, however various their physical pro- perties, have nevertheless the same chemical composition. And many of them are easily converted into grape sugar ; either by the excitement of a limited metamorphosis by an azotised ferment, or by exposure to the action of dilute acids. The sugary ingredient of the human milk forms about 5\ per cent, of its quantity; and is the only representative of the hydrates of carbon which it contains. The average amount of the substances belonging to this and the preceding group of alimentary constituents will of course vary greatly in different kinds of food. Speaking generally, however, each of these two predominates by turns in the food derived by Man from the two kingdoms of nature. Thus while the hydro- carbons are chiefly derived from the fat of animal food, the hydrates of carbon are represented even more ex- clusively by the starch and sugar of vegetable f But, in strictness, no such marked difference can actually be made out between the two kinds of food in this respect. The milk, the liver, and even the blood of the animal, all contain sugar : while inosit, a substance closely allied to sugar, and indeed, identical with it in composition, forms an important constituent of the various muscles. Conversely, not only do many plants contain large quan- ALIMENTARY CONSTITUENTS. 63 tities of oily matter stored up in various parts of their tissues, but even the seeds of those Cerealia, which form the best vegetable diet, present an amount of fat ranging from '2 to 2 per cent. The purposes fulfilled by these hydrates of carbon in the animal economy, offer a marked contrast to those subserved by the two previous groups. The proteinous compounds furnish what is eminently the basis of the organism ; — the plasma from which are developed the blood and the tissues. They are thus histogenetic and hcemagenetic, as the phrase is. The fatty matters of the body not only form a large constituent of the ever active nervous substance, but are also retained and stored up in the more inert and passive form of adipose tissue. While the grape-sugar, into which the various hydrates of carbon of the food are all finally converted, seems not to undergo any such assimilative process as permits it to enter largely into the composition of the tissues, and to assume, in so far, a permanent form in the body, but is, to all appearance, rapidly eliminated from the blood. In what shape, or after what metamorphoses, it leaves this fluid, is at present uncertain. It is, however, probable, that like the hydro- carbons, these hydrates of carbon are essentially a species of fuel for that process of calorific combustion, which pervades the whole body, and which discharges its re- sulting carbonic acid by means of the respiratory function. And Liebig has adduced numerical data from the fattening of animals, which lead him to suppose, that these sub- stances are also capable of undergoing such a process of de-oxidation, as converts them into fat, and thus enables C4 THE NATURE OF FOOD. them to augment the adipose tissue. But this view rests on what are at present very insufficient foundations * : and is curiously contrasted with that oxidation f of hydro- carbons into sugar^ or some kindred substance, which the researches of various recent observers seem to indicate as one of the chief functions of the liver.J 4. The importance of the water of the food is such a> justly entitles this liquid to the rank of a fourth alimentary constituent. For it forms about four-fifths of the entire corporeal mass : and undergoes, at the various excretory surfaces of the skin, the lungs, and the kidneys, a con- tinual expenditure ; the replacement of which is obviously necessary to the maintenance of the proper composition of the body. * The increase of fatty matter supposed to have been derived from tl hydrates was calculated by subtracting the fat added in the vegetable food from the increase of the animal's weight : this BUiplue as due to augmented adipose tissue. Hence any error in estimating the fatty constituent of this food on the one hand, or any neglect to calculate the watery and proteinous constituents of the increased adi the other, would partially account for the difference L And it seems not unlikely that both of these inaccuracies actually occurred in these observations. f Assuming that such a metamorphosis really obtained, it would not be difficult to explain most of Liebig's results without supposing any such direct metamorphosis of starch into fat as that above alluded to. For it might well be expected that the presence of an excess of sugar in the liver would diminish the energy of this act : in other words, that an exe the product would lessen the activity oi the process. Thus the copious ingestion of sugar might check its formation, as well as diminish the me- tamorphosis of the fat supplied to the liver in the portal blood. And this retention of the fatty form might not only affect the hydro-carbons of the food, but also those which are possibly developed in the org... from its own proteinous constituents. + Compare the remarks on the liver, in Chapter V. ALIMEXTAEY CONSTITUENTS. 65 The way in which this large aqueous constituent fa- cilitates the action of the several organs is not very difficult to conjecture. Their merely physical properties of hard- ness, flexibility, and the like, often seem greatly influenced by the quantity of the watery ingredient which they contain. And their more recondite vital properties seem quite as immediately under its influence. Thus not only do its solvent powers appear to be eminently useful in furthering the minute division, and the local transfer, of various organic substances, but we are justified in believing that it gives a specific chemical assistance to many of those processes of metamorphosis which are so intimately con- nected with Life. In both of these respects it seems specially to aid the function of digestion. Besides, that act of absorption which conveys the dissolved con- tents of the alimentary canal into the surrounding veins, is greatly facilitated by the heightened diffusive energy which the low specific gravity of water enables it to impart to the fluids with which it has been mixed. And finally, the use of water in relation to the opposite ex- treme of nutrition — namely, to excretion — may be well exemplified by the urine; a poisonous product which is continually being washed out of the system, through the instrumentality of a stream of this universal solvent. The details of death by thirst afford a fearful com- mentary on the above remarks ; — although, from reasons which will presently be mentioned, it is obvious that even these cases rarely afford us examples of the complete exclusion of all entry of water from without the body. After a period of agonising thirst, the most distressing F 66 THE NATURE OF FOOD. symptoms of which seem referrible to the dry and in- flamed throat and fauces, the deficiency of water is gradu- ally revealed by a diminution — which is at last almost a suppression — of the various secretions that normally contain a large proportion of this liquid : namely, the sweat, the urine, and the faeces. Increasing muscular debility accompanies this change ; and is soon followed by delirium and coma, ending in death. And, conversely, the benefits afforded by water seem to receive an almost paradoxical illustration from its effects in the opposite states of starvation and of fattening. Thus, as regards the latter process, animals are stated to fatten much more easily and quickly when allowed the free ingestion of this liquid. And Becquerel and Leh- mann state that, when water is taken in excessive quantity, an increased amount of urea is excreted from the system of the healthy human subject.* While the researches of Bidder and Schmidt f show that, even after the withdrawal of all other ingesta, the copious use of water concedes to the starving animal a longer duration of life ; — diminish- ing not only the waste of its protein-compounds, but those collateral results of its vital processes, which are exemplified by the excretion of urea, carbonic acid, and salts. Hence water, which forms about 85 per cent, of the milk, is an universal constituent of the food of animals : and varies only in the proportion which its amount bears * An effect which is partially aseribable to its favouring the absorption of a larger quantity of protein from the same amount of food. t Die Verdawungssaefte and der StonVechsel. Leipzig. 18o2. p. 344. ALIMENTARY CONSTITUENTS. 67 to that of the solid ingredients mixed with it, or dissolved in it. In some of the lowest forms of animal life, its relative amount is so great, that the remainder of the food is only present in the state of a very dilute solution. In certain aquatic creatures of this kind, the medium around the animal seems to form such a dilute alimentary solution as only requires an act of absorption at the outer surface of the creature's body. And even in the higher animals, in whom the other alimentary constituents are always taken into a stomach or internal cavity, part of the total quantity of water which really accompanies them into the system is often introduced by the same mode of absorption. So that, although the relative amount of water consumed within a given time by the organism has probably a definite proportion to the activity of the vital processes, the amount of this liquid habitually swallowed by any animal is greatly affected by the quantity introduced in other ways : namely, by the proportion contained in its solid food, the amount formed by the combustion of hydrogen in its body, and the quantity absorbed by its skin from the vaporous or liquid water of the surrounding media. Thus the apparently dry food of many Herbivora is explained by the large amount of water, which is present as a chemical constituent of such food, and which accompanies its few digestible parts into the system. And the small amount of drink taken by many of the Batrachian reptiles is chiefly due to the active tegumentary ingestion last alluded to. The quantity of water contained in the various kinds of food ordinarily made use of, will be referred to here- I 2 68 THE NATURE OF FOOD. after. But we may probably fix its average at about 75 to 80 per cent, (or about 5 lbs. daily) of the mixed fluid and solid food (about 6*5 lbs.) of the human subject. 5. The salts of the food constitute the fifth and last group of its constituents, and that which we may be said to know less of than all the others. For, while many of the more important salts are easily recognised in the ashes of the various fluid and solid aliments in which they are usually introduced into the body, still we are often at a loss to know the precise state of combination in which they are originally present in the food, far more than that in which they enter into combination with the organism itself. In the case of many salts, we can, however, trace the actual changes of composition which occur in the organism. Thus the salts composed of the various organic acid- united with the alkalies, are converted into carbonate-. prior to their dismissal from the body in the urine. And it seems possible that even the sulphates are occasionally decomposed in the alimentary canal ; their sulphuric acid being deoxidised into sulphuretted hydrogen, while their bases unite with the carbonic acid formed in the system. Hence, although a careful and repeated analysis of the salts contained in the organism arid in its total excretions, might afford some clue to the qualities and quantities the salts which ought to be introduced in the food, it would not by any means represent the details of these demands. While it is hardly necessary to add that no such series of examinations has ever vet been made : and ALTMENTABY CONSTITUENTS. 69 that, however carefully conducted, it might easily over- look very small quantities of important ingredients. Many discrepancies, however, it would probably clear up ; such as why animals which in one region seem indifferent to salt, in others seek it with the greatest avidity ; — why the diet which produces scurvy in one person, leaves another little affected ; — or, for example, why the roving population of the South American Pampas can maintain a robust health on the fresh meat of the wild cattle which range these plains ; while an apparently similar diet on the flesh of tame cattle has been known to decimate a regiment of English soldiers. The more essential salts of the food seem to be the chlorides and phosphates of the alkalies; and especially, the chloride of sodium, and the phosphate of soda. Lime and iron are also important bases. In healthy human milk, the salts amount to about 2 parts per 1000. Of these about -J-rd seem to be soluble ; consisting chiefly of the chlorides of potassium and sodium (as 3 to 1 respec- tively) ; and of phosphate, sulphate, and even carbonate of these bases in similar proportions. The insoluble salts are chiefly tribasic phosphates of lime and magnesia (as 8 to 1 respectively) ; the large quantities of which are doubtless connected with the exigencies of ossification in the foetus. F3 70 CHAP. III. DIGESTION. — ITS FIRST STAGE. Definition and Summary of the Process. — Mastication. — Insalivation. — Salivary Glands. — Their Structure. — Secretion. — Physical and Che- mical Properties of Saliva. — Its Quantity. — Stimulants of its Flow. — Its Action ; mechanical, general, and special Functions. — Influence of its various Sources. — Relation to the Stomach and its Secretion. — Deglutition : in the Pharynx — in the (Esophagus — at the Cardia. The food, of which the general composition was briefly described in the foregoing chapter, undergoes in the in- terior of the body a series of changes which fit it for ab- sorption into the vessels. The aggregate of these changes we term digestion; a word which, — originally used only to signify a supposed arrangement, or setting in order, of the various ingredients of the food prior to their H con- coction" or seething together into an uniform liquid, — is now taken to mean the whole process which conducts nutriment from the exterior of the body into the veins and lacteals ; through which it passes to traverse the lungs and the heart, to be thence propelled into the arteries, and so to reach the mass of blood contained in the capillaries. The highest powers of our microscopes show that neither of these two classes of absorbent vessels of the dig tive canal — veins and lacteals — possess any pores ca- pable of directly receiving solid particles of appreciable SUMMAEY OF DIGESTION. 7i dimensions. Hence in the mixture of solids and liquids which forms the food, the absorption of the nutritious materials of the former class of substances requires the aid of various processes, such as may confer on them the liquid form. And even those alimentary substances originally liquid sometimes require a further change. The total act of digestion may therefore be summed up as implying — (1.) The minute division of the food. (2.) Its successive exposure to the action of a series of solvents, each of which is destined to dissolve certain of its in- gredients. (3.) Its subjection to a series of metamorphoses, all of which are strictly limited to certain degrees of decomposition, any progress beyond which is subversive of digestion, and therefore, to however small an extent, of health itself. But the digestive canal is also, like most other organs, in some degree self-regulative : and is thus the seat of (4.) an action which checks or arrests all such excess of digestion as would injure the organism by flood- ing the vessels with an injurious superfluity of nutritious matters. And (5.) the necessity of removing from the canal the insoluble and useless ingredients of even the purest food, seems to suggest the intercalation, so to speak, of the organs of various excretions, some of which also subserve other purposes prior to their own extrusion from the body ; facilitating or checking the metamorphoses of the food, or balancing an undue plethora by a converse increase in the rapidity of their own outflow, or in the quantity of their own mass. Mastication is the first action to which the food is submitted, The anterior or cutting teeth having severed P 4 72 DIGESTION. a morsel of food, the tongue, which is endowed with an exquisite sense of touch at its surface, and with a cor- respondingly delicate and complex faculty of movement as the office of its muscular mass, now places the food, supposing its consistence to require mastication, between some of the posterior or grinding teeth. Eetained be- tween the apposed surfaces of these by the tongue in- ternally, and the muscular wall of the cheek externally ; and triturated by a double movement (antero-posterior and lateral) of the teeth on each other, in the horizontal plane, at the same time that it is also crushed by the opposition and compression of the jaws in the vertical plane, the food is rapidly reduced to a minutely divided state. The perpetual changes of position which aid this action are also made use of to mix with the food a variable quantity of a liquid poured largely into the mouth by various secreting organs, the salivary glands. Insalivation, as this act of admixture is termed, con- stitutes an important element of the digestive procesa Hence the structures and secretions which effect it are correspondingly numerous and energetic. Three large glands on each side: — the parotid, between the jaw and ear; the sub-maxillary, behind and below the jaw, where it adjoins the neck ; and the sublingual, visible by raising the tip of the tongue, as a crescentic swelling in front of this organ — constitute the chief sources of this secretion. In addition, however, to these, there are numerous smaller glands, termed conglobate, from their ordinary shape, and of diameters varying from £rd to 2 or 2i lines, which raise the surface of the mucous membrane lining I^SALIVATIOX. 73 the mouth [into little swellings, named, according to their situation, buccal, lingual, labial, and palatine glands. Fie. 1. Conglobate oral gland, magnified 50 diameters. {After Koelliker.) a, Areolar investment ; b, efferent duct ; c, gland- vesicles ; d, ducts of the lobules. The structure of all these glands is comparatively uniform. The duct or canal by which each opens into the interior of the mouth is of a width proportionate, in the main, to the total bulk of the gland of which it forms the conduit, and to that stream of secretion which it there- fore, at the period of greatest activity, has to convey. Its 74 DIGESTION. length, for reasons equally obvious, varies according to the distance to which its orifice in the mouth is removed from the gland itself. But in spite of the great variations thus permitted, the essential structure of all the salivary glands is identical. Traced backwards from its terminal orifice, each has a duct, the thick wall of which perforates the mucous membrane by what is, in all but the smallest specimens, a tube formed of muscular and elastic tissue. Within this tube is enclosed a thin structureless membrane lined by epithelial cells, possessing characters closely ap- proaching those of the cells of the mucous surface on which it opens. By repeated divisions, which are mostly bifurcations, the duct continually diminishes in its dia- meter as it increases in distance from its orifice, until finally its ultimate branches, reduced to a diameter of Fig. 2. Diagram of two ducts of a lobule. {After Kocttiker.) a, Efferent duct of lobule ; bb, side branches ; c, vesicles in situ ; d, the same separated, and the duct unfolded. about Y^th of an inch, suddenly expand into a number of crypts of about 1£ times this size. The inner sur- face of the ramified duct is clothed with a flat polygonal tessellated epithelium of small size (^Vo thincl1 dieter), forming but a single layer. (Fig. 3.) This cell-growth, SALIVARY GLANDS. 76 into which the larger coarser epithelium of the oral cavity merges at a short distance from the commencement of the duct, is of exceedingly delicate structure, each of its nucleated particles being exclusively occupied by a faintly granular and albuminous liquid. A few allusions to the vascular supply, and to the mecha- nical arrangement, of these branched ducts may complete this brief notice of the structure of the salivary glands. Wrapped in areolar tissue (which here, as elsewhere throughout the body, subserves the double purpose of a physical protection to the vessels and nerves, and a means Fig. 3. Two vesicles of a conglobate oral gland, magnified 300 diameters. (After Koelliker.) a, Basement membrane ; b, epithelium, as seen in transverse section ; c, from the surface. of convoying and attaching them to the organs they supply), the chief differences between the largest and smallest of these salivary glands, — between the massy and irregular parotid, and a buccal gland scarcely larger than an ordinary millet-seed, — relate to the number of packages, so to speak, into which the gland is divisible, and to the amount and complexity of the areolar envelopes thus 76 DIGESTION. required for its total mass. In the larger glands, the terminal dilatations of the ducts can hardly be extricated or unravelled from out of their dense sheaths of areolar tissue. But the dilatations themselves, when thus exposed, permit their apposed surfaces to be seen in the shape of a cluster of spherical or irregularly polyhedral vesicles, something like a bunch of grapes. And the circumstance that each cluster of adjacent vesicles is packed in its own special layer of connective tissue, as well as supplied by its own vessels, and can thus be isolated as an egg-shaped lobule of about § rds by -±-rd of a line in size, completes the likeness to such an independent bunch of acini or grapes. Adjacent bun- ches or clusters, however, are again packed and swathed into still larger masses by layers of areolar tissue thrown around the externa] or unopposed surfaces of the smaller or primary bunches ; these, again, are aggregated by other and more external investments into still larger masses ; thus consti- tuting primary, secondary, tertiary, quaternary, &c- lobules of the gland : the last or greatest of which aggregations as it were, finally built up into the total mass of the large salivary gland by a common envelope of similar connective tissue, which merges, by an increasing laxity of its meshes, into the ordinary areolar structure in which the gland is imbedded. The smaller size, and the less exposed position, of the sub-mucous conglobate glands reduce these repeated sheathings to two or three only ; and even these are of a softness and delicacy consonant with the greater delicacy and moisture of all their tissues, as shown by ordinary dissection, — a delicacy which, for the most part, concurs with such a situation as well shields them from all ordis SALIVA. 77 mechanical injury. The capillaries which unite the small arteries and veins of each primary cluster or lobule sur- round the limitary membrane of each terminal acinus with three or four loops of variable shape and size, analogous in Fig. 4. Capillaries of a lobule, magnified 80 diameters* arrangement to those which supply the vesicles of the adipose tissue. It may be added, that each class of glands has its peculiarities of colour and consistence, which, unlike its microscopic structure, readily distinguish it from all others, and are attributable in great part to the nature and amount of its vascular and areolar constituents. The secretions of all these glands are mixed together in * From Dr. Hyde Salter's Essay, " Pancreas," in the " Cyclopsedia of Anatomv." 78 DIGESTION. the mouth to form the saliva or spittle, which is added to the food in the act of mastication or chewing. But it is probable that the products of the two classes of salivary glands — the sub-mucous or racemous, on the one hand, and the proper salivary (parotid, sub-maxillary, and sub- lingual) on the other — differ from each other in some im- portant particulars. The secretion of the smaller glands — the oral secretion, as we may term it — is but scanty in amount, probably not exceeding three or four ounces in 24 hours. Essen- tially structureless, it usually contains a variable admix- ture of epithelial scales derived from the surface of the mucous membrane of the mouth, with a few oval cyto- blasts or cells, referable to the deeper or younger layers of the same epithelial growth, from which they casually abort or are abraded. It is a transparent, yellow, viscid, frothy liquid, which contains about one per cent, of solid ingre- dients, and has a distinctly alkaline reaction. Of the dry residue left by its evaporation at a low temperature, about -^th is an extractive compound soluble in alcohol ; and rather less than frds consists of salts, among which the chlorides of potassium and sodium, and the phosphate of soda, make up the larger part (87 per cent. ) The secretions of the conglomerate or proper salivary glands are more alkaline, as well as more copious and watery than the preceding* : in other words, they have a smaller specific gravity (about 1004) and dry residue * It is probable that this concentrated character of the oral mucus is partially ascribable to a re-absorption of some of its watery ingredient after its secretion, SALIVA. 79 (about 5 and 7 parts per 1000 in the case of the parotid and sub-maxillary respectively). Of this solid part, about one-third is organic; the remainder consisting of salts, among which saline constituents the carbonate of lime * often forms one-fifth to one-third ; the remainder being chlorides of the alkalies, and the sulpho-cyanide of potas- sium, or rhodankalium, as it is sometimes termed. The sub-maxillary gland appears to furnish a denser and more potent secretion than the larger parotid. That mixed secretion of all these structures which forms the ordinary spittle, will of course vary in com- position according to the share furnished by the several glands. In the human subject, its specific gravity, on an average about 1008, corresponds with a dry residue forming about 7 parts in the 1000 ; and composed, it would seem, pretty equally of a soluble organic substance, salts, and admixed epithelium. Contrasting this com- position with that of the saliva of the dog, it would appear that the spittle of Man is more dilute, or watery (as 10 to 7) ; that it contains much more casual epithelium ; and lastly, that, as regards its salts, it includes far more phosphates, and less chlorides. The alkaline reaction of the spittle is subject to con- siderable range in different individuals, even during perfect health. It especially varies, however, with the condition of the salivary organs; being most alkaline when these are excited by the presence of food, and by the act of mastication, to pour out their secretions in large * Perhaps formed by a decomposition of the carbonate of soda of the original secretion by its calcareous salts. 80 DIGESTION. quantity. It also varies materially with the existing condition of the health. Wh ether secondary or otherwise, a kind of lactic fermentation of the saliva has been noticed by me for some years past as no very uncommon result of its being kept a few hours at a heat of 100° Fahr.* And a variety of morbid states of the salivary organs, teeth, gums, and stomach, as well as of the other parts of the digestive canal, may give rise to an abnormal acidity of the mixed secretion. The minute proportion of the sulpho-cyanide of potassium (according to Bidder and Schmidt, less than one part in 16,000 of the mixed human saliva) throws great doubt on the theory of its specific or characteristic share in the sali- vary function. It appears to be contained chiefly, if not exclusively, in the secretion of the parotid. The soluble organic substance called diastase, or ptyaliu, has far better claims to be regarded the chief ingredient of the total secretion. It is soluble in water, but precipitable by alcohol ; and dries into a yellow, glutinous-looking in which analysis shows to have a composition akin to that of albumen, but suggests to be (like albumen itself) a mixture of several ingredients in variable proportk rather than any single and constant organic compound. The quantity of saliva can scarcely be estimated with exactness; but may be conjectured as amounting to about 3 pints in 24 hours. It will naturally vary according to * The bearing of this fact on the large proportion which lactic acid been alleged to form in the gastric juice, and even on its. possible replace- ment of the hydrochloric acid originally present in this secretion, is a too large and controversial fitly to enter upon here. (Compare, how, the remarks on the gastric juice in the following chapter.) SECRETION OF SALIVA. 81 the idiosyncrasy, health, circumstances, and especially the food, of the individual. The large demands made on this secretion by chewing a dry biscuit on a hot day, and the con- trast of masticating a peach or an apple, suggest their own conclusions. Eeduced to figures, however, this contrast ranges from an admixture of about 4 per cent, of saliva with the fruit, to 150 or even more with the dry bis- cuit. Even to juicy and well-cooked meat not less than 40 or 50 per cent, of saliva is generally added during mastication. The secretion of saliva, however, not only varies in quantity according to the nature of the food, and its re- quirements as to salivary admixture, but also remits from time to time in correspondence with the state of digestion ; so as to contrast an exceedingly copious flow, during the ingestion of food, with a scanty moistening of the mouth, during the intervals of meals, by a liquid which, in all probability, comes chiefly from the oral glands, if not alto- gether from these, to the exclusion of the larger secreting structures of the parotid and sub-maxillary. As respects the mechanism of these fluctuations, the increased salivary flow of the digestive act is evidently due to a stimulation of the nerves distributed to the various glands concerned : the galvanic irritation of the larger of these nerves pro- voking a copious flux of saliva, with a pressure upon the walls of the corresponding ducts such as has been shown by Ludwig greatly to transcend that of the blood-column in the carotid artery, as well as in the veins of the gland concerned. The process by which this stimulation is brought about G 82 DIGESTION. offers all those various links which its suitable connection with other elements of the digestive act would almost seem, a priori, to imply. The recollection, sight, or smell of pleasant food constitutes what we may roughly term a cerebral stimulus ; which, obviously reflex in its course from the eye or nose to the centre of perception in the two latter cases, is, perhaps for the sake of con- venience rather than accuracy, regarded in the first emotional and efferent only. Mastication and speech, again, which visibly further the flow of saliva, are by some supposed not to increase secretion, but only mechanically to assist the emptying of the ducts. But the large and continuous flux sometimes witnessed as the result of con- tinuous speaking shows that secretion itself is often — perhaps generally — augmented by this motive stimulation, if we may use such a phra0& The oral stimulus of the ingestion of food is both a more natural and effective stimulation, and a more strictly reflex phenomenon. How little, however, the sensation which for obvi purposes is usually associated with the afferent stage of this act, is necessary or essential to it, may be illus- trated by the well-known experiment of Beaumont, Blond- lot, and others on the living body: where the intro- duction of food through a fistulous opening into the stomach has been instantly followed by a copious secre- tion of saliva, even though the entry of the food into this insensible organ has been managed quite unconsciously to the animal itself. The action of the saliva is partly mechanical. Adding to the food a viscid liquid admirably adapted for its dilu- ACTION OF SALIVA. 83 tion and moisture, it thus greatly reduces the friction which the mastication or minute division of the alimentary- morsel would otherwise inevitably imply ; at the same time that it doubtless inaugurates the general process of digestion by a scanty, but genuine, solution of all the more soluble constituents of the food. To this, its casual and interrupted office, we may also add another, which, though in some respects mechanical, has yet a profound physiological im- portance, both as regards digestion and the organism at large: — namely, that the saliva constitutes part of a vast stream of liquid, which, poured into the upper part of the alimentary canal day by day, to undergo a re-absorption as regards the greater part of its bulk in the succeeding seg- ments, after more or less of change during its transit, con- stitutes a kind of off-shoot of the general circulation, such as must in itself materially aid and modify the general current of blood toward the capillaries from whence it is poured out. Nor can it be doubted, that the large salivary contribution to this stream must especially modify those secretions with which it is first mixed in the stomach and intestine, as well as influence the liver, and the portal blood sent to this organ ; — the goal, and the pathway, respectively, of the re-absorbed constituents of the saliva. The more specific function of the saliva consists in the conversion of the starch of the food into sugar, as the first step towards its assimilation and absorption into the body. Operative chemistry has longtaught us the facility with which various re-agents effect this change out of the body ; and has especially shown us how — under the influence of dilute acids, decomposing animal matter, warmth,, and moisture — starch. G 2 84 DIGESTION. and various substances of allied composition undergo the metamorphosis (little more, we may conjecture, than a re- arrangement or new grouping of their atoms) necessary for the conversion of these forms of hydrate of carbon* into the higher and more useful state of grape sugar. And considering the rapidity with which decomposition is set up in most animal secretions and tissues when with- drawn from the influences of the living organism, and subjected in their natural or wet state to a blood-heat of 103°Fahr., it is not surprising to find that there are many animal fluids and solids which, under such circumstao can effect this change. The distinction, however, which entitles us to regard the conversion of starch into sugar as constituting a more special function of the salivary >t-cre- tion, is simple and conclusive. The change brought about by saliva is rapid, intense, and unattended by putre- faction ; so that a few seconds often suffice to deprive a solution of starch of all power of reaction to the delicate test of iodine. And with the exception of the pancreas and the glands of Brunnerf, no other tissue or secrttiuii of the body seems at all to approach the rapidity and potency of the salivary glands or the saliva respectively, in effect- ing this metamorphosis. The mixture of secretions, however, seems to be so far essential, as that the larger salivary glands alone would scarcely furnish a saliva of sufficient energy. Indeed, some observers regard the oral mucus as quite indispensable to an active metamorphosis of starch. Certainly, there are * See p. Gl. j See Chapter V. DEGLUTITION. 85 various young Mammals in whose saliva such a power of conversion seems little developed soon after birth. This appears especially to hold good of the parotid gland. It does not appear that the gastric juice influences the saliva, save by the lowering effect of dilution. So little sugar, however, can generally be found in the stomach when occupied by starchy food, that, in the absence of any better explanation, we are fain to suppose that the saccharine solution set free by the metamorphosis of starch is forth- with absorbed with extreme rapidity by the veins of this organ. Deglutition, which passes the food onwards from the mouth through the pharynx and oesophagus into the stomach, as the next stage of the digestive act, is a process so rapid and transient, and of so little direct influence on the mechanical or chemical properties of the food, that we may dismiss it with few words. The obliteration of the oral cavity by the rising of the tongue against the roof of the mouth forces back part of the mouthful of chewed and insalivated food towards the aperture of the palate, and between the tonsils; the mucus covering which is thus wiped off against the alimen- tary mass, so as to lubricate its outside while it is being moulded into a kind of semi-fluid bolus. The mass, which next enters the pharynx, is prevented from rising into its upper segment by the descent of the contracting muscular curtain of the soft palate ; at the same moment that its descent into the larynx, below the base of the tongue, is prevented by the larynx and epiglottis being G 3 86 DIGESTION. forcibly carried tipwards, so as to close their laryngeal aperture by pressing both of them against the muscular cushion of the tongue itself. The food has thus but one course open to it : namely, a descent into the funnel- shaped pharynx, the constrictor muscles of which propel it into the upper aperture of the oesophagus continuous with the lower part (or apex) of their own conical tube. The oesophagus or gullet, the tube of transmission which intervenes between the pharynx and stomach, extends as a hollow cylinder nearly along the median line of the body from the fifth cervical to the eleventh dorsal vertebra, opposite the left border of which it perforates the dia- phragm, to enter the belly, and open into the stomach. Its three coats or layers — the fibrous, muscular, and mucous — correspond with those found in the intestinal canal, where the peritoneum (or serous covering) replaces its outermost or fibrous layer. The muscular coat is divisible into two planes ; of which the external, twice as thick as the internal, consists of a mixture of the two kinds of muscular fibre known as the striped and unstriped — the latter, however, greatly predominating: and the former being limited to a scanty admixture, chiefly occupying these upper segments of the tube which adjoin the pharynx, and are continued into it. The inner oesophageal coat, the mucous, itself also thickened or strengthened by an admixture of unstriped muscular fibres, is characterised by a thick epithelium, the cells of which, forming many layers, are liable to a kind of natural division in the dead subject, not unlike that seen in various regions of the skin, a thick white (ESOPHAGUS. 87 cuticular stratum being raised or detached by serum from the thinner and more transparent layer beneath. A few sub-mucous glands, analogous to the conglobate salivary glands of the mouth, lubricate the oesophageal contents with a thick mucus during their rapid transit through the tube." The transit itself is effected by a peristalsis, or transverse constriction, of the muscular fibres of the oesophagus ; a constriction in which the longitudinal fibres probably play but the subordinate part of fixing the ex- tremities of the tube, and preventing that elongation which a transverse narrowing would otherwise ineffectually end in. The passage of the alimentary bolus occupies but a few seconds ; and terminates with its descent into the stomach, through the cardiac aperture of which it is followed by a kind of temporary intus-susception of the lower part of the oesophageal tube. A series of nodules or warty projections distinguish this orifice of the stomach, to which they doubtless act as a kind of imperfect valve during its muscular contraction. C 4 CHAP. IV. DIGESTION. THE STOMACH. The Stomach. — Its Shape, Size, Attachment, Situation. — Its Structure. — Serous Coat. — Muscular Coat. — Movements of this Coat, and of the Gastric Contents. — Pyloric Valve. — Mucous Coat. — Tubes. — Lenticular Glands. — Matrix. — Areolar Tissue. — Vessels. — Nerves. — Lymphatics. — Digestive Changes. — Gastric Juice. — Its Physical Properties. — Chemical Properties. — Physiological Properties. — Peptone. — Action of Gastric Juice. — Process of its Secretion. — Summary of Gastric Digestion. The stomach, the widest and most dilatable part of the alimentary canal, has a form which varies somewhat in different individuals. Removed from the body, and moderately distended, it generally takes the shape here represented (Fig. 5) — a shape best described as that of a bent cone, the concave aspect of which receives a tube at one fourth of the distance from its base. In it we distinguish an anterior and a posterior surface : a superior and an inferior border ; a right and a left extremity : and lastty, the cardiac and pyloric apertures, by which it com- municates with the cesophagus and duodenum respectively, and thus becomes continuous with the remainder of the digestive canal. The description of these parts varies with the state of the organ. Thus, when empty and uncontracted. the THE STOMACH. 89 stomach is flattened vertically ; its anterior and posterior surfaces touching each other, while its upper and lower margins really deserve the title of " borders." But when the organ is distended, any transverse vertical section becomes almost a circle, its borders and surfaces merging into each other. Its uppermost part, however, is still distinguishable as the lesser curvature (a, e, 6, Fig. 5), Fig. o. Stomachy as seen by inflating it, and dissecting off its peritoneum, its longi- tudinal, and part of its transverse muscular coat. a, g, Cardia ; b, b, pylorus ; a, e, b, lesser curvature ; g, d, f, c, b, greater curvature ; g, d, to near /, cardiac sac ; c, b, b, e, pyloric sac. (Above a, g are seen the transverse fibres of the oesophagus ; and below these, the upper, most of the oblique fibres of the stomach, passing towards c. Covering the pyloric sac are seen the transverse fibres. The dotted line, a, e, b, shows how extreme distention of the stomach tends to alter the lesser curvature.) and its lower as the greater curvature (#, cZ, /, c 9 b). The general concavity of the former curve is especially marked in its first three fifths, at the end of which part (e) it usually becomes slightly convex. A shallow notch (c) 90 DIGESTION. often divides the greater curvature into two portions opposite this pointy and, with the latter, defines the com- mencement of the pyloric pouch (c, ft, fe, e). The cardiac pouch, great or splenic extremity (d) is the part to the left of the oesophageal opening (a), beyond which it projects for about three inches. At this aperture the oesophagus dilates gradually, so as to resemble an inverted funnel. To the right of the oesophagus, the stomach expands slightly, to reach its maximum diameter at about the middle of the organ (/). Beyond this point it tapers away to the pylorus (6, b) 9 where a sudden constriction marks the side of the valve. The dimensions of the organ are even more variable than its form. In the healthy middle-aged male, the moderately distended stomach is about thirteen to fifteen inches long; and its diameter at the widest part five, near the pylorus two, inches. Its total surface is about one and a quarter square feet; its capacity about 175 cubic inches, or five pints ; its weight seven ounces.* The attachment of the stomach is effected chiefly by the continuity of its extremities with the more fixed duodenum and oesophagus. The former tube is connected with the posterior wall of the belly ; the latter perforates the diaphragm, so as to enter the abdomen about one inch in front of the left border of the aorta, by an aper- ture which is everywhere muscular, though close to the * For women and children, these estimates require a proportionate reduc- tion. They are increased by habitual distention, and by the relaxation of old age ; diminished by habitual exercise, or by the practice of taking small meals (as is usual in dilative emphysema of the hugs). SITUATION. 91 posterior border of the tendon. The fixation of the stomach is also aided by certain processes of peritoneum. To the left of the oesophagus, the short phreno-gastric omentum passes from the diaphragm to the cardiac pouch, which it reaches somewhat posteriorly. Still lower down, the stomach is united to the spleen by the gastro-splenic omentum. The lower border of the organ gives off the great omentum; this descends for some distance towards the bottom of the belly, and is then reflected upwards to the anterior border of the transverse colon, which it splits to enclose. The upper border of the stomach is attached by means of the gastro-hepatic or small omentum, which descends from the transverse fissure of the liver. All of these folds are double ; though the four layers of the reflected omentum majus are often inseparably united to each other. Situation. — The stomach is placed almost transversely in the upper part of the abdominal cavity, in which it passes from the left to the right side, as well as down- wards, and slightly forwards. This direction results from its situation relatively to the oesophagus and duodenum ; since it is joined by the former at its highest part, and near its left extremity, while the latter is immediately prolonged from its right or pyloric end. In this course •from left to right, the stomach successively occupies the left hypochondriac and the epigastric regions ; and, just at its termination, it reaches the right hypochondrium. Its anterior surface is therefore in contact with the dia- phragm, where this muscle lines the cartilages of the left false ribs, and with the wall of the abdomen. Its 92 DIGESTION. posterior surface lies upon the pancreas, the aorta, and the crura of the diaphragm, where these parts cover the spine. Its left extremity is in contact, above, with the diaphragm ; below, with the spleen ; and, posteriorly, it reaches the left supra-renal capsule and kidney. Its upper border is in apposition to the liver, viz., to its left lobe, to the lobnlus Spigelii, and to part of the lobvJxs quadratus. Its lower border is parallel, and close to, the transverse colon. Unusual distention or size chiefly affects the situa- tion of the organ, by causing it to extend downwards, as to overlap or displace the transverse colon, and thus to reach the umbilical, the left lumbar, or even the left iliac region. Under similar circumstances, its left extremity also passes more deeply into the corresponding hypochon- drium, so as to be more extensively covered by the ribs. Its extension upwards diminishes the size of the thorax* but is rarely sufficient to be felt as a serious hindrance to the descent of the diaphragm in ordinary tranquil inspiration. Its right extremity may touch the gall- bladder. It may be useful to trace the effect of progressive dis- tention of the stomach upon its form, site, and fixation. When void of food, and not distended (as it often is | by gases, the flattened stomach hangs almost vertically in the epigastrium. In this state of the organ, the pulpy food that enters it from the oesophagus drops at once into the cardiac pouch, which forms its most depending part. The reception of further quantities effaces its upper and lower borders; and gradually changes them, from slightly bent lines, into the curves above mentioned, at the same time 6 EFFECT OF DISTEXTIOK 93 that it separates the previously apposed surfaces, and con- verts the whole organ into a cone, convex below and in front. The latter of these two convexities is most marked at the pyloric extremity, and is often very sudden. Both result from the increased length of the organ, and the proximity of its comparatively fixed orifices. But both are assisted by the construction of the muscular coat, since the distention of the separated stomach imitates, though it scarcely equals, the curves taken by the organ when mo- derately expanded in situ. The delicate and yielding omenta just enumerated allow the stomach to expand be- tween their elastic and extensive layers, without under- going any disturbance of its nervous and vascular con- nexions, or any loss of its serous covering. Finally, although the stomach itself enlarges pretty equally in all directions, still, after filling the left hypochondrium, the mobility of its bent middle directs it towards that part of the enclosing cavity where it meets with the least resist- ance — namely, towards the yielding anterior wall of the belly. Hence, should the distended intestines not allow it any great descent downwards, it comes forwards ; so that what was its vertical surface now looks obliquely upwards, while its inferior border touches the lower part of the wall of the epigastrium, where its artery has even been felt pulsating in very emaciated subjects. In common with all the sub-diaphragmatic segments of the alimentary canal, the stomach is composed of three coats or tunics: — an external and serous, a middle and muscular, and an internal and mucous coat. The first of these attaches the organ to the cavity in which it is en- 94 DIGESTION. closed; and limits, permits, and facilitates those move- ments which it is the chief office of the second to execute. The third is the most important, forming the secreting and absorbing surface on which the functions of the organ chiefly depend. The serous coat of the stomach is continuous with the double layers of peritoneum before mentioned, which split to enclose it where they reach its various borders. Here they are very loosely connected to each other, and to the subjacent coat, by an abundance of highly elastic areolar tissue. But towards the middle of the gastric surface, the peritoneum, though still elastic, is el united to the subjacent muscular tunic. The advantage of this mode of attachment has already been referred to. The structure of the serous coat is precisely that of the visceral peritoneum elsewhere. A single layer of flattened epithelia, of hexagonal shape, rests upon a stratum of areolar tissue, containing the scanty vessels by which this cell-growth is nourished. Immediately beneath the epithe- lial layer, the areolar tissue is condensed and firm : and its aspect in contact with the cells shows the smooth continu- ous outline of what is, developmentally, a basement mem- brane, but is actually inseparable from the fine yellow fibres beneath, through which it gradually merges into loose, elastic, sub-serous tissue. The large meshes of the latter enclose a variable quantity of adipose tis>ue. The muscular coat of the stomach consists of the un- striped or organic muscular fibre, which Koelliker has shown to be constructed of fibre-cells (Fig. 6, c. 6), The length of these cells is from Tr-Jroth to T ^th of an inch: MUSCULAR FIBRES. 95 their breadth from -g- 5V0** 1 to XoVoth a ^ the middle, where they are flattened, and from whence they taper off to conical and pointed extremities. They contain a nucleus, which is from 2^tli to 1 \ th of an inch in length, and about a sixth of this in breadth. Their texture is a pale sub- stance, apparently homogeneous, but consisting, in reality, of a membrane enclosing granular or faintly striated contents. In other instances they are marked by swellings (as in 6), which, as they are rarely seen in the associated fibres, are probably due to casual local contractions of the sarcous substance itself. The arrangement of these fibre- Fibre-ctlls of the Tinman stomach, magnified 450 diameters, a, Fibre-cell, as usually seen; b, fibre-cell, with more wavy, irregular edges. cells is very simple ; they are packed together in parallel rows, their flattened surfaces adhering strongly to each other. They thus form small bundles, between which are interposed the vessels for their supply, enclosed in a spar- ing quantity of areolar tissue. The union and interlace- ment of these fascicles build up the strata of the muscular coat. The development of the fibre-cells takes place by the elongation of an oval cell, in which at the same time is deposited a sarcous content, that soon obscures the ori- ginal cell-membrane. In the intestine these fibres are arranged in two layers — an external, in which the bundles take a longitudinal 96 DIGESTION. course ; and an internal, in which they are circular or transverse* to the axis to the tube. But, in the stomach, the peculiar shape of the organ is associated with a modi- fication of this arrangement. The longitudinal layer of the stomach is derived from the similar tunic of the oesophagus. This, on reaching the cardia, radiates on all sides ; its bundles becoming thinner as they diverge to be gradually lost among the various fibres with which they decussate and interlace. But, on the lesser curvature of the organ, they continue much more distinctly ; and are often traceable, as two or three broadish bundles, to within a short distance of the pylorus. The longitudinal layer which covers the pyloric extremity appears not to have any very direct continuity with the preceding. Its constituent fibres arise by scattered bundles at about the middle of the organ, and — often first uniting into two broad bands which occupy the middles of its anterior and posterior surfaces — they soon form a tubular kyer, which proceeds over the pylorus, to join the com- mencement of the duodenum. The transverse or circular fibres lie immediately beneath the preceding, and form a much thicker layer. To the left of the cardia, its rings are very few and indistinct : their places being taken by those of the third or oblique layer. But from the right of this orifice, it continues towards the pylorus (p, Fig. 7), with a constantly increasing thickness, until finally, reaching the margin of this valve, it is in- flected towards the axis of the stomach by a rather steep or * Probably in reality spiral For the grounds of this conclusion, see the description of these fibres in Chapter V. MUSCULAR LAYERS. 97 sudden curve, which presents an almost vertical surface towards the duodenum. Those of its fibres which lie nearest to the left extremity are somewhat less regularly- transverse. Hence some of them decussate slightly with each other; while others, which pass downwards from the right margin of the cardia, are directed somewhat obliquely towards the left extremity of the organ. Longitudinal section of the stomach and duodenum, to show the pyloric valve, v, Pyloric sac of the stomach ; I, its longitudinal muscular coat ; tr, its transverse coat, gradually thickening into p, the pylorus ; d, commencement of the duodenum, The third, or oblique layer, lies more deeply than the two preceding ; and is therefore best seen by everting and inflating the stomach, and carefully removing its mucous membrane. Where the oesophagus enters the stomach, the transverse fibres of its left margin are so close to a flattened bundle of fibres, which occupies the notch ((7, Fig. 5) limiting the cardiac pouch, that the two are visibly continuous. The right or thickest part of this flattened band passes obliquely downwards towards the right side, soon breaking off from the termination of the oesophagus ; and from hence it continues across the trans- it 98 DIGESTION. verse layer just described, to reach -the greater curvature, where the similar layers from both surfaces of the organ ar£ reflected into each other. Its usually well-defined margin occupies — and indeed forms — the notch ( the delicate limitary or basement membrane sustains a number of minute cells which bound the cavity of the canal. Examined by the naked eye in situ, the mucous mem- brane of the stomach is seen as a tolerably firm but soft layer, of a pale pink colour, which everywhere loosely lines the interior of the muscular coat, and projects from its surface in numerous wrinkled folds. These rugce chiefly occupy the cardiac half of the organ, forming convolu- tions which, though somewhat irregular, are mainly longi- tudinal. They are effaced by distention of the stomach. On putting the mucous membrane on the stretch, we may often discern that its whole internal surface is occupied by extremely minute pits or depressions ; the confluent and projecting intervals of which become so much longer as they near the pylorus, that they may be compared to short villi. These depressions are the openings of the stomach- tubes or proper gastric glands. The stomach-tubes (a, 6, c, cl, Fig. 10) may be described as cylinders of basement membrane, which are packed vertically side by side in a sparing matrix of dense areolar tissue, and are filled by a peculiar cell-growth. Below, they terminate in closed and rounded extremities (d). Above, they expand slightly before reaching the free sur- face of the membrane (at a); where their margins finally become continuous with each other, so as to form a series of low ridges, the height and width of which vary some- what in different parts of the stomach. The length of 106 DIGESTIOX. these tubes is, on an average, about ^Vth of an inch. Their diameter is about -33-0-th of an inch. Thus their length has to their breadth a proportion of ten or twelve to one. Fig. 10. Vertical section of the stomach, near its middle, and parallel to its Magnified 30 diameters, a, Openings of stomach-tubes, and their intervening ridges or \ : tions ; b, upper parts of the tubes, lined by columnar epithelium ; c. lower parts, occupied by proper gastric cells : d, pounded ends of the tub- g dense areolar tissue, containing fibre-cells, and continuous with the inter- tubular matrix ; /, submucous areolar or cellular coat, of a looser texture, and containing vessels (some of which are seen cut across"): 0. trans layer of the muscular coat ; h, longitudinal layer ; i. peritoneal coat. Their form frequently so far deviates from that of a simple cylinder, as to present slight constrictions or undulations. GASTKIC CELLS. 107 And occasionally they even exhibit a kind of csecal pouch or blind offset of greater or less length. These pouches usually spring from the lower extremities of the tubes, which have generally a somewhat increased diameter in their neighbourhood. But with these exceptions (which are, I believe, the result of mechanical violence) the gastric tubes form simple, straight cylinders, and only widen where they open on the inner surface or cavity of the stomach. The limitary or basement membrane of these tubes pre- cisely resembles this delicate homogeneous layer in other mucous structures, possessing an equal (or even greater) tenuity. It is usually seen only as a dark outline, bounding some isolated part of a tube. Earely, however, it may be identified as a delicate, floating, and collapsed fold ; which, on the addition of a dilute alkali, first swells up, and then disappears. On the ridges which unite the tops of the tubes, it is quite impossible to separate it from the sub- jacent structures : — an intimate adhesion, in striking con- trast to the ease with which we can often isolate it from the matrix around the tubes themselves. As regards the contents of these tubes, the upper fourth or fifth of their length presents a single layer of columnar epithelium (6, Fig. 10; a, a, Fig. 11). Seen as isolated cells, the particles of this epithelium have a cylindrical shape, and enclose a very distinct nucleus near their at- tached extremity. But when seen in their natural situ- ation, and from the free side of the mucous membrane, they appear as hexagonal prisms ; containing nuclei, which are so near to their lower ends, as to be separated from 108 DIGESTION. the basement membrane by little more than their cell- wall at this part. The remainder of the tube is, under normal* circumstances, always occupied by oval or some- what angular cells (at c, Fig. 10; c> c, Fig. 1 1), of considerable Fig. It Upper part of a tube from the middle of the human 'stomach, showinp the arrangements of its columnar and oval cells. Magnified 200 and 800 diameters. a, a, Columnar cells of the upper part, free and in situ ; b. b. small an- gular cells, also free and in situ, into which these merge below, to form a central or axial layer within c, c, the proper gastric or glandular cells, also free and in situ, size. The largest of these oval cells are about 1 .^ th of an inch in diameter. They have a more or less distinct * In reference to the alleged expulsion of these during gastric digestion. compare p. 128. GASTRIC FOLLICLES. 109 membranous wall. The nucleus they contain is usually in contact with that side of their parietes which is attached to the basement membrane of the tube ; and it sometimes exhibits a nucleolus. Their contents are finely granular, with here and there refractile dots, which have a close resemblance to oil-globules. And, besides the above granular material, most of these cells appear to en- close numerous (5—15) pale, flat, and extremely delicate cytoblasts. The centre of the layer formed by these cells is apparently lined by a series of small angular cells (6, 6, Fig. 11), which surround and enclose a narrow thread-like calibre or cavity ; and above, merge into the columnar epithelium of the upper part of the stomach-tube. The interstices of the oval cells seem to be occupied by granules and minute cytoblasts. Lenticular glands are also found in the stomach. As regards their shape, size, situation, and contents, they cor- respond with the follicles* or solitary glands of the intes- tine. Their number varies extremely. Sometimes it is impossible to find any. In other specimens, they are scattered more or less thickly throughout the whole organ. They are said chiefly to affect the lesser curva- ture ; but I have seen them sown very plentifully over the pyloric region only. In children, they are rarely absent. Matrix. — The cylindrical tubes of the stomach are united to each other, in their whole height, by a sparing quantity of a fibrous network or matrix ; their blind ends also resting upon a layer (e, Fig, 10) continuous with that * See the description of these structures in the following chapter. 110 DIGESTION. surrounding their sides. Near the free or cavitary surface of the stomach, this dark firm matrix is almost homogeneous. But in the deeper parts of the mucous membrane it is easy to distinguish, in addition to vessels, fibres which surround the tubes, and decussate with each other. This matrix, which also surrounds the intestinal tubes, and thus extends from the cardia to the anus, is composed of a variable admixture of areolar tissue with unstriped muscular fibres. The latter appear to pass from the oblique and transverse layers of the muscular coat, through the areolar tunic, to reach the intervals of the stomach-tubes in the form of bundles which decussate at an acute angle. The action of these fibres is probably connected chiefly with the adjustment of the mucous membrane to the effects produced by the contractions of the proper muscular coat. Areolar tissue. — A layer of loose sub-mucous areolar tissue (the tunica nervea of authors) connects the mucous and muscular coats. Seen in vertical sections ('/, Pig. 10), its thickness is a little greater than that of the layer of matrix beneath the ends of the tubes. It is composed of the ordinary white and yellow fibrous elements : the fila- ments of the latter being chiefly of small size. Externally, it is firmly connected with the muscular coat, from which it receives fibres, and to which it sends off processes to form the septa of the muscular bundles. But more inter- nally, where it approaches the fibrous matrix, its meshes are very large and loose ; so as to allow the mucous mem- brane to be thrown into folds by the contraction of the GASTEIC VESSELS. Ill muscular tunic. It contains the vessels, nerves, and lymphatics, which supply the other coats. The vessels of the stomach are very large and numerous. The arteries are derived from the abdominal aorta. The veins empty themselves into the vena portce, which rami- fies in the liver. Fig;. 12. Arteries of the stomach, as seen by raising this organ, to show their origin from the cceliae axis. s, Stomach ; d, duodenum ; I, liver ; p, pancreas ; sp, spleen ;j, jejunum ; a, a, coronary artery ; b, splenic artery ; c, left gastro-epiploic artery ; e, vasa brevia ; f superior pyloric artery ; h, hepatic artery ; m, superior mesenteric artery ; n, aorta ; q, q, right gastro-epiploic artery. The arteries come from the cseliac axis* This vessel, which leaves the aorta opposite the first lumbar vertebra, continues obliquely forwards, as a short thick trunk, for 112 DIGESTION. about half an inch, when the " axis " ceases by giving off, at right angles to itself, three large branches : — the gastric, hepatic, and splenic. The distribution of these branches may be summed up as giving to the stomach an artery, from two sources, along each of its curvatures*, with numerous vertical anastomoses between these two horizontal vessels on each of its surfaces. Indeed, all the arteries and veins of the stomach are cha- racterised by the great freedom and frequency of their inosculations, in every stage of their course from the aortic to the portal trunks. This condition is especially well marked in the arteries, which in number and size far exceed those distributed to an equal bulk of most of the other structures of the body. This fact is doubtless con- nected, not merely with the large supply of blood they send the stomach, but also with a smaller resistance, and greater velocity, in their channels ; and especially with that efficient and sudden control of their calibre which the varying exigencies of the gastric circulation would seem to imply. Their tortuous course, and their loose connection with the stomach, chiefly refer to the distention of this organ. For as the stomach extends between the layers of omen- tum, it gradually straightens these vessels, and alters their position with respect to itself and each other. The distal branches of both arteries and veins perforate the muscular coat at different intervals, by twigs which unite with each other in the loose sub-mucous areolar tissue, so as to form two flattened networks : — one. which * Shown in the figure on the preceding page. GASTEIC CAPILLARIES. 113 is composed of small arteries ; — and another, of veins. The vessels of the latter plexus are, as usual, both larger and more numerous than the corresponding arteries. Capillaries. — The arterial branches which leave this sub-mucous network to enter the dense muscular layer of the matrix of the stomach, divide here once or twice. And their ultimate ramifications, which have a diameter Fig. 13. Diagram showing the vessels of the mucous membrane of the stomach, as they would be seen in a vertical section. Magnified 30 diameters. a, Small artery of the plexus in the sub-mucous areolar tissue; t, capillaries forming a network around the stomach-tubes ; r, larger capillaries, forming a superficial network on the ridges which separate the open mouths of these tubes ; v, veins, formed by branches from the latter network, and ending below in the sub-mucous plexus. of about , * n th to 1 o O ^y^-th of an inch, pass vertically up- wards, along the sides of the tubes, to their upper aper- tures, where they form a superficial network of capillaries. In passing upwards, they also give off other capillaries f 114 DIGESTION. which surround the tubes at all parts of their height, so as to form a second and deeper network. The meshes of this latter plexus are somewhat oblong (t 9 Fig. 13), but less de- cidedly so than those of the capillary network of striped muscle; and are about y^o"th to ^-^h of an inch in size. The capillaries which compose them are, on an average, little more than j^th of an inch in diameter. The more superficial network is contrasted with this deeper one, not only in the fact that its capillaries are about double the above size (or 2S * th of an inch), but also in its meshes Fin. 14. Superficial capillaries of the gastric raucous membrane, from an irr specimen. Magnified 60 diameters. (Fig. 14) being nearly twice as close (or about -^th to -g^th of an inch). But the two plexuses inosculate so freely as to be quite continuous with each other at the upper apertures of the tubes. As regards the form of the superficial network, it corresponds exactly with the inter- vals of the tubes. For the ridges which occupy the surface of the organ are all, as it were, moulded upon capillaries ; the union of which forms a network that sur- rounds the aperture of each tube with a loop or ring GASTRIC CAPILLARIES. 115 (r, Fig. 13), complicated by the addition of other meshes (Fig. 14) on either side of it, just within the orifices of the tubes. In shape and size, these meshes closely resem- ble the loops beneath the ridges ; and are, indeed, no way distinguishable from them except in their situation. Below, their diameter diminishes ; their loops elongate ; and they finally merge into the capillary network which surrounds the tubes. It is from the large capillaries which compose the super- ficial network that the radicles of the veins almost exclu- sively arise. They begin as small vessels of about 15 1 00 th of an inch in diameter; and, by one or two successive unions of these and of their resulting larger branches, soon attain a width of about xoT^ °f an inch. They now pass vertically downwards between the tubes, to open into the venous plexus of the sub-mucous areolar tissue. The general result of this arrangement on the circula- tion in the stomach is, that the blood which has already traversed the capillaries of its tubes is further transmitted to its surface ; and that, in respect to their size and situa- tion, the superficial capillaries of the gastric mucous mem- brane offer some analogy to veins. Hence, it is probable that the velocity of their contents far exceeds that of the blood circulating in the capillaries of many other tissues. Such a peculiarity would admirably adapt them to that absorptive office, which their situation on the cavitary surface of the stomach indicates to be one of their chief functions. The nerves of the stomach are derived from two sources : from the pneumogastric, and the sympathetic, nerves. I 2 116 DIGESTION". The branches of the pneumogastric nerves leave these trunks at the lower end of the oesophagus ; and, after a variable course in a nearly vertical direction — those of the left anteriorly, those of the right posteriorly, to the stomach — they perforate the muscular coat. Diminished in size, they then ramify in the sub-mucous areolar tissue ; in which they may be traced for a considerable distance, until lost from increasing minuteness, on the under surface of the mucous membrane. The sympathetic nerves distributed to the stomach are branches from the great prevertebral centre of this nerve in the belly : — from the vast and complex ganglion formed in front of the aorta by the semilunar ganglia laterally, and by the solar plexus which unites these in the middle line. The large plexiform ganglion thus constituted u r ives off a process — the coeliac plexus — which envelopes the cceliac axis with a dense network of nerves; itself further breaking up into subordinate plexuses around the coronary, hepatic, and splenic branches of this arterial trunk (a, b, /'. Fig, 12 . Closely interlaced around these vessels, and doubtless from time to time distributing branches to their coats, the plexuses corresponding to the arteries just mentioned | along them to the stomach ; which they reach to penetrate the muscular coat, and to disappear in the sub-mucous tissue, like the gastric branches of the pneumogastric nerves. The lympfJuxtics of the stomach consist of two sets : — one beneath the peritoneum, immediately outside the muscular coat ; another (a plexu of larger vessels, with more frequent communications) in the sub-mucous coat, GASTRIC JUICE. 117 between the mucous and muscular tunics. They anasto- mose freely at the ends of the stomach with the lymphatics of the liver, spleen, and pancreas ; and are still more directly continuous with some glands, which are of small size in the healthy individual, and are chiefly placed near the lesser curvature of the organ. Changes during digestion. — The inner surface of the healthy fasting stomach is of a pale pink colour. The mucous membrane, itself always exhibiting an acid reac- tion, is covered by a thin stratum of alkaline fluid, derived (as its chemical and microscopical examination abundantly proves) from the various secretions which enter the organ by the oesophagus and duodenum. The introduction of food gives rise to two chief alterations in the state of the stomach. Its muscular coat is excited to the movements already described; and at the same time its mucous membrane deepens to a bright pink colour, and begins to pour forth a liquid — the gastric juice. Physical properties. — Pure gastric juice is a transparent, limpid, structureless liquid, of a pale straw colour. Its taste is distinctly acid; and its smell a peculiar faint odour, characteristic of the species of animal from which it is derived, and allied to that of the blood. Its specific gravity is about 1003 '3. In the healthy human adult, the quantity secreted during the twenty-four hours probably ranges from ten to twenty pints; and under favourable circumstances* its maximum in an hour may be estimated at not less than six or eight pints. The chemical properties of the gastric juice are best * Such as long fasting followed by a large meal of meat. I 3 118 DIGESTION. noticed by successively considering its acid, saline, and animal constituents. The gastric acid. — Omitting exceptional instances, in which acetic, butyric, and other acids allied to these pro- ducts of organic decomposition, have been found in ineffi- cient quantity in the contents of the stomach — and further eliminating the view taken by Blondlot, which ascribes the acidity of this secretion to the presence of the acid phos- phate of lime — there are two views of sufficient importance to demand notice. One of these regards the gastric acid as the hydrochloric, and another as the lactic, acid. There can be no doubt that each of these acids has been re- peatedly found in the gastric juice as the chief or cause of its acidity.* There is just as little doubt that they are sometimes present together; and that* even in the same species and individual f, the hydrochloric maybe replaced by the lactic acid. While we shall Bee that either of the two would suffice to restore to a neutralised gastric juice its original digestive powers. But a careful consideration of the facts hitherto known leads me to the opinion, that, in these latter cases, the lactic acid is always a secondary and accidental product : and that the balance of evidence inclines decisively to- wards a single acid of the gastric juice, which, as normally secreted, owes its acidity exclusively to hydrochloric acid.J * Lactic acid by Chevreul, Lassaigne. Thomson. Lehniann. Payen. Bern Frcrichs, and Smith; hydrochloric by Front. Punglison, Braconnot. T. rnann, Enderlin, Schroeder. Bidder, and Schmidt. t In Alexis St. Martin, as it would appear from a comparison of analyses by Dunglison in 1S33. and F. G. Smith in 1S-56. I Compare author's Essay, "Stomach," (>^. cit. p. S'oO. GASTKIC JUICE. 119 Salts. — As regards the salts of the gastric juice, the details of an analysis of this secretion may be best com- prehended (if not explained) by comparing them with a similar quantitative examination of the liquor sanguinis. The following table* exhibits such a comparison, for a thousand parts of both fluids. Water . Animal matters Mineral substances Chlorine Sodium Potassium (in dog, '2 ?) Phosphoric acid Phosphate of lime Phosphate of magnesia (Lime corresponding to '624: Ca. CI.) Liquor Gastric Sanguinis. Juice, 903*0 973*2 88-5 170 8-6 9-8 3-6 5'6 3-3 1-2 •3 •6 •2 •6 •3 1-2 •2 -2 •3 1000-0 1000-0 Hence, while most of the salts of the blood are present in increased quantity in the gastric juice, the chloride of sodium is so greatly diminished, as to lower the total saline contents of this secretion below those of the blood-liquor. While the amount of hydrochloric acid is so great, as not only to compensate this loss, but even to raise the total of its mineral constituents above that of the blood-liquor. The origin of this acid is obvious. Its mere quantity is * Here the composition of the gastric juice is calculated from an analysis by Schmidt ; and that of the blood-liquor is quoted from Lehmann (Physio- logische Chemie, Bd. ii. pp. 153, 179). To facilitate comparison, both analyses are reduced to one place of decimals ; and the phosphate of lime of the former is divided into acid, and neutral phosphate. I 4 120 DIGESTION. sufficient to refer it to the chloride of sodium, which is the most plentiful chloride of the parent fluid. And the re- markable diminution in the sodium of the secreted fluid further confirms this view. Indeed, it is interesting to notice that almost all the differences between the salts of the two fluids may be included in some such hypothesis that of — (1) a rapid transudation of the blood-salts gene- rally, followed by their concentration through an absorption of part of their water of solution; (2) a decomposition of about half of the chlorides, and chiefly of the chloride of sodium * ; and (3) a return of the base of this salt into the blood. While it is evidently to a derivation of acid from some of the constituents of the latter fluid that we must refer the important fact established by Dr. Bence Jones: — namely, that, during digestion, the healthy urine loses the acidity proper to it at other periods. Organic substance, or Pepsi/ne, — The addition of alco- hol to pure gastric juice, or to a watery infusion of stomach, causes a white flocculent precipitate ; which, when dried at a low temperature, forms a much less voluminous mass, of a yellowish grey colour, and a somewhat gummy ap- pearance. This substance reddens litmus, and is soluble in cold water ; but may be again precipitated from its aqueous solution by alcohol. Its ultimate composition * Such a decomposition would obviously present many analogies to an electrolysis. But though the acid and base are certainly unloosed a: parated, the process itself cannot be definitely referred to this cause in the existing state of our knowledge. We may. however, notice, that both the quantity and quality of the chloride of sodium would render it more suscep- tible to electrolytic action than any other of the salts present in the blood- liquor. PEPSINE. 121 closely resembles that of the various protein-compounds, from which it differs chiefly in containing more nitrogen. And even its other chemical properties bear out this re- semblance : its differences from many of the albuminous compounds consisting chiefly in the fact, that it is not precipitated from its watery solution by some of the salts which would throw down dissolved albumen. Allowing for variations due to impurities, the reactions of gastric juice, and probably of pure pepsine, are as follows. It is not precipitated by heat, ferrocyanide of potassium, sulphate of copper, alum, chloride of iron, or mineral acids. It is precipitated, though not completely, by bichloride of mercury. Carbonates of the alkalies pre- cipitate its lime-salts. And the soluble salts of silver and lead throw down the chlorides of these metals. In all of these instances a portion of the pepsine is carried down with the precipitate. In the case of the salts of lead the greater part of the pepsine is thus deposited, but may be almost wholly recovered by washing. Action of the gastric juice. — The addition of a few drops of dilute hydrochloric acid to a solution of the above precipitate in cold water, constitutes a liquid which pos- sesses energetic solvent powers over ordinary animal food. Hence the organic substance itself has been termed pepsine {7rsy]rt9 9 concoctio) : — a name to which there can be no objection, so long as its meaning is confined within proper limits ; and is not extended to imply a single and definite organic compound, capable of digesting all the alimentary principles. Temperature exercises an important influence on the 122 DIGESTION. gastric solvent. At the ordinary temperature of the at- mosphere, the action of the gastric juice is scarcely per- ceptible, even when continued during many hours. Lower degrees of cold suspend its action still more completely. Heated to the temperature of the body, namely, to about 100° Fahrenheit, it acts very energetically. A further accession of temperature at first increases, but soon in- jures, and finally destroys, all its digestive powers. The precise point at which this change of effect occurs is not clearly known; but it is probably at or near 120°. The dried pepsine of the artificial digestive fluid will, however, sustain a temperature of 160° without damage. But at a heat above this, it becomes wholly inactive, and partially insoluble. And the pepsine of pure gastric juice is stated by Dunglison to be insoluble in hot water. Alcohol, acids, and alkalies, when applied in excess, have also a destructive influence on the digestive power of pepsine. In the case of acids, this injurious effect is much less marked. As might have been expected from the constant reaction of the gastric juice, an acid is essential to its digestive efficacy ; — indeed, we might almost say, to its very existence. Even that incomplete loss of acid, which is necessarily involved in the precipitation of its pepsine, must be compensated by an artificial aeidula- tion, before an aqueous solution of this substance regains its former powers. Here, however, as in the case of heat, it is necessary that certain limits should be observed. About half the quantity of hydrochloric acid present in the gastric juice forms a tolerably effective EFFECT OF REAGENTS. 123 fluid. But the normal proportion (about 3 parts per 1000) may be increased to three or four per cent., not only with impunity, but even with advantage. The nature of the acid seems a matter of indifference. Nitric, phosphoric, sulphuric, acetic, and lactic acid, have all been successfully made use of. And the range of amount already specified for hydrochloric acid might, a priori, prepare us for the fact, that the requisite quan- tities of these acids seem solely related to their more or less dilute state, and do not allow us to recognise any traces of equivalent proportions. Applied in still larger quantities, all of these acids first weaken, and then destroy, the digestive power of the solution of pepsine. The comparative amount of injury inflicted by equal quantities of the different acids appears to depend (like their solvent efficacy) chiefly on the degree of their concentration. The essential aid given by the acid, is well shown by the effect of neutralising a natural or artificial gastric juice with an alkali. Under these circumstances, it not only loses all action upon albuminous substances, but, if mixed with them, shares their putrefaction. Left to itself, however, its powers are only suspended, being renewable by the addition of an acid. The addition of a larger quantity of alkali permanently destroys all its solvent powers, and is followed by its rapid putre- faction. But though an acid is thus one of the essential elements of a digestive fluid, it must not be thought that any such agent can imitate the gastric secretion, even when asso- 124 DIGESTION. ciated with an infusion of saliva, mucus, intestine, bladder, or other animal product or tissue. The solution accom- plished by such fluids is excessively slow, superficial, and imperfect; and affords, not that new compound produced by gastric juice from albuminous substances, but a weak and turbid solution, which readily yields its dis- solved constituents to ordinary reagents. And even in the case of an acidulated infusion of intestine — where the results are probably affected by the diffusion of gastric juice over the whole digestive canal — the nature and amount of the process do not allow it to be any way com- parable with that effected by gastric juice. The effect of the neutral salts on artificial digestion has scarcely been investigated with all the attention it merits. But it is probable that many of these inorganic substances assist solution, when present in small quantities, and oppose it when added in excess. This is especially the case with chloride of sodium, the ordinary condiment of Man and of many animals. The effect of alcohol is also regulated by its amount and concentration. Diluted, it seems to have no chemical action whatever. In larger quantities, as before remarked, it precipitates pepsine. And in still greater excess, it permanently destroys all its digestive energy. In respect to the solvent properties of the gastric juice on the various protein-compounds, an exact determination of the quantity of pepsine which these substances require for their solution, would greatly assist us in solving many problems with respect to the chemistry of digestion. But the estimates derived from actual experiment are very PEPTONE. 125 conflicting, — if, indeed, they can be considered really comparable. It may, however, be estimated, that one part of pepsine will dissolve about fifteen of moist and finely divided abdomen : while the gastric juice itself possesses the power of dissolving from fifteen to twenty per cent, of its weight of the same substance. The gastric juice dissolves, not only the various protein- compounds, but gelatin, chondrin, and gluten. In doing so, it arrests (and generally removes) all decomposition or putrefaction which they may be undergoing. The mere physical condition of ^the substances to be dissolved remarkably influences the rate of the process : density and bulk rendering it slow, while conversely, it is accelerated by minute division. The quantity of solvent required varies with the nature and aggregation of the particular substance. In any case, the ultimate effect is that of a complete i solution, containing a substance which (as shown by j Mialhe and Lehmann), whatever the substance originally ! dissolved, possesses certain properties, entitling it to the '; name of peptone. Peptone. — The following properties are common to all kinds of peptone. Eeduced to the solid form by careful evaporation, it is a white or yellowish-white substance; almost tasteless and inodorous ; very soluble in water ; but insoluble in alcohol of eighty-three per cent. Its watery solution reddens litmus, and is precipitated by chlorine, tannic acid, and metallic salts; but is unaffected by boil- ing, by acids, or by alkalies. With alkalies and bases, it forms very soluble neutral compounds or salts. An aque- 126 DIGESTION. ous solution of these is still less precipitable by reagents than one of peptone itself. Thus it is only thrown down by tannic acid, bichloride of mercury, and a mixture of the acetates of ammonia and lead: — the acetate of lead, and the ferrocyanide of potassium, causing but a faint cloudiness ; and even concentrated acids, nitrate of silver, and alum, having no effect. The ultimate chemical composition of any particular peptone so closely resembles that of the substance from which it is formed as scarcely to require any further notice. In speaking of these chemical phenomena of stomach- digestion, there remains but to notice, that the addition of water, or a small quantity of fresh acid, is capable of re- storing some of its original digestive powers to saturated gastric juice, or to a solution of peptone. The above properties of the gastric juice naturally sug- gest the question — What is the nature of its action ? In answer to this question we may premise, that it is obviously no simple process of solution by a dilute acid ; no mere contactive influence (like that of spongy platinum in the acetification of alcohol); no mere fermentation (like that excited by yeast in a solution of sugar); no mere combination of a complex acid with protein-com- pounds which constitute bases (as in the " hydrochloro- pepsic " view propounded by Schmidt). If we must connect the above details by some theory, we may first remark, that the gastric juice dissolves pro- tein-compounds ; that it renders them highly soluble ; and that it assimilates their form and reactions to its own, THEOEY OF GASTKIC JUICE. 127 without changing their composition. For any parallel to such a process we can only look to those lower degrees of chemical action, where solution and combination, adhe- sion and affinity, may be supposed to meet and merge into each other ; where proportions are tolerably definite, but true equivalents indistinct ; and where, though form is changed, and reactions modified, elementary composition remains little affected. Actions of such a kind may be found in the union of many substances with water, or its elements, to form the compounds called hydrates. And the conversion of protein into peptone, by the gastric juice, presents so many analogies to the formation of a hydrate*, that it seems not impossible the chief office of this secretion may be that of enabling water to combine with the various members of the albuminous groups of alimentary substances; in order to their acquiring that solubility, and uniformity of constitution, which must probably precede their admission into the current of the blood. To this vague indication of a theory, I will only add, that the mode in which a definite quantity of the organic principle takes part in such a process cannot even be conjectured. Its action certainly appears no way com- parable to the effect of diastase on starch, or of emulsine on amygdaline. It seems to be an assimilation, in the strictest chemical sense. It is not impossible that the acid commences the process by a slight, though genuine, solution of the more resisting substances. And at any rate, this constituent seems to have the power of checking * Compare Prout " On Stomach and Eenal Diseases," fifth edition, p. 470. i 28 DIGESTION. putrefaction, if not of arresting all metamorphosis, in the other ingredients of the secretion : like the small quantity of sulphuric acid which is added by the chemist to hydro- cyanic acid with the same object. Process of secretion. — The process by which the gastric juice is secreted from the mucous membrane of ^the sto- mach can scarcely be regarded as known, even in its larger phenomena. To correct some prevalent errors, and to offer a conjecture which future researches alone can fully substantiate, is all that the author would attempt here. The secretion of gastric juice is not effected by any ex- pulsion of the glandular contents of the stomach-tubes. Their elaborate and dimorphous structure might alone suffice to prove this proposition. And the mere quantita- tive objections to such a view are scarcely less conclusive.* Bat it is better refuted by two facts: (1) that during every stage of gastric digestion, the tubes may be seen with precisely the same form, size, arrangement, and con- tents!, which they exhibit during the fasting state; and — (2) that the pure gastric juice is completely structure- less. As regards the visible details of the act of secretion, Dr. Beaumont has reported some interesting observations. He made use of magnifying glasses, by the aid of which he could distinguish the spheroidal glandular follicles, and the * This expulsive view, applied to the human stomach, during diges* would imply the entire reconstruction of its cell-growth from 60 to 1 times in one hour ! t The greater softness and delicacy of these contents is no exception to this fact. PROCESS OF SECKETIOX. IC9 papillce situated in their interstices. These papilla, or villi, he found to be scarcely visible until food was applied to the mucous membrane ; when they underwent a kind of erection, and protruded from its surface in the shape of small sharp processes. (Compare Figs. 10, 14.) From these, according to this faithful observer, the gastric juice appears to exsude. Its secretion begins by the gradual appearance of innumerable lucid specks, which are smaller than the mucous follicles. These specks or points rise through the transparent mucous coat ; and seeming to burst, discharge themselves upon the very points of these vascular papHl&, as a thin, transparent, colourless, limpid, acid fluid, which collects in small drops, trickles down their sides, and spreads over the whole gastric surface.* Comparing this description with what we now know respecting the anatomy of the mucous membrane, it is difficult to avoid coming to the conclusion, that the large and numerous capillaries beneath its ridges are intimately connected with the secretion of the gastric juice ; as well as with the absorption of peptone and other dissolved in- gredients of the food. And such an office is further sug- gested by the fact discovered by Bernard, that it is only the surface of the mucous membrane which exhibits an acid reaction, either in the digesting or fasting state, f * So thoroughly persuaded \ras Dr. Beaumont (op. cit.) that the fluid exsuded from the papilla alone, that he had not the least doubt the excre- tory ducts of the follicles ^vere inclosed in these villi, and terminated in the lucid specks just alluded to ; although he admits that he could not see any apertures here. f In verifying this observation, I have sometimes found, belovr the sur- face, a faint acidity, such as might be derived from the mere imbibition of the acid fluid from above. K 130 DIGESTION. It would therefore seem, that the ridges and papilla which separate the apertures of the tubes on the free sur- face of the gastric mucous membrane, secrete what is, quantitatively, a large proportion, and qualitatively, the acid ingredient, of the gastric juice. And I am entitled to add, that it appears very probable that the tubes them- selves, and the specific glandular or oval cells they con- tain, are chiefly (if not exclusively) concerned in the secretion of the organic principle ; which exsudes from them as a solution, the density and quantity of which remain for the present unknown. We may end these remarks by a summary of the share of the stomach in digestion generally. The mastication and insalivation of the food is imme- diately followed by its deglutition, which propels the pulpy or semi-fluid mass it now forms into the stomach. On entering this organ, it is subjected to a special act of gastric digestion, the total duration of which may be estimated as averaging two hours. The energetic action of the mixed saliva is not affected by the gastric juice secreted by the stomach. Much of the starch of the food is probably converted into sugar during the short sojourn of the aliment in this cavity. The sugar thus produced would seem to be absorbed by the vessels of the gastric mucous membrane with extraor- dinary rapidity. The w^ater, salts, and soluble organic compounds of the food are similarly taken up. And the gastric juice attacks and dissolves the proteinous element of the food. The perfection of this process of solution depends on the mechanical state of the substances con- STOMACH. — DIGESTION. .131 cerned, and on the quantity and efficiency of the active liquid. Of the resulting solution or peptone, part is im- mediately absorbed by the gastric vessels, while part passes on into the duodenum, in company with protein which has not yielded to the solvent process, as well as with unsaturated gastric juice. Much of this protein ultimately becomes dissolved, and, with the peptone which accompanies it, is taken up by the veins of the intestine. That, of all the secretions poured into the alimentary canal, the gastric juice alone has the power of converting the albuminous compounds into peptone — is a proposi- tion which has too direct a bearing on the function of the stomach to be omitted here, though the reasons which demand its reception cannot be adduced. But while referring to the following chapter for the chief facts which militate against the possession of any share in this power by the intestinal and pancreatic juices, I would add, that it is evident the gastric juice retains its digestive efficacy after passing the pylorus ; and that it is to the presence of this secretion (concentrated, perhaps, by absorption) that the solvent action on protein, attributed by many able physiologists to these other secretions, are doubtless due. K 2 132 CHAP. V. DIGESTION. — THE SMALL INTESTINE. The Intestine. — Small Intestine. — Duodenum ; its three Portions. — Mesen- tery. — Convolutions. — Jejunum. — Ileum. — Muscular Coat. — Its Move- ments; as deduced, observed. — Theory of its Peristalsis. — Mucous Mem- brane. — Valvules Conniventes. — Tubes. — Their Secretion, or "Intestinal Juice." — Villi. — Their Constituents, including the Lacteals. — Their Changes during Digestion. — Absorption of Fat. — Follicles ; Agminate, Solitary. — Racemose Glands. — Accessory Organs. — Paneiva-. - Structure. — Secretion or Pancreatic Juice. — Its Physical. Chemical, Pro- perties. — Its Share in Digestion; or Action on (1) Starch, (2) Fat, (3) Protein-Compounds. — Liver. — Its Supply of Blood. — Ita Physical Charac- ters. — Its Structure; Capsule V Umaes, Ducts. — Ita two-fold Function. — The Bile. — Its Quantity : as influenced by the Gall-bladder. — Its Composition. — Its two-fold Destiny; Excretion. Resorption.- Influence on Digestion. — Its Sources. — Influence of the Liver on Diges- tion. — Contrast of Portal and Hepatic Bloods. — Progress of Digestion in the Small Intestine. The intestine begins at that external constriction which corresponds to the pylorus (p, Fig. 15), and marks the boundary between the stomach and the intestinal canal. The latter, at about five sixths of its length downwards, is divided into two portions by a change of size, correspond- ing to the presence of a ccecum or blind appendage (cc) without, and of a valve within the tube. Of these portions, the upper, long and narrow, is called the small intestine : and the lower, short and wide, the large intestine. The small intestine, cylindrical when distended, has an SMALL INTESTINE. 133 average length of 20 feet, and a diameter of 1J inches. But its yielding texture allows it to be narrowed by exten- Fig. 15. Stomach and intestinal canal of the adult human subject, c P, stomach ; c, cardiac ; p, pyloric orifice ; J i, small intestine ; J, jeju- num ; i, ileum ; c c to a, large intestine, viz. : — -c c, caecum ; a c, ascending colon ; t c, transverse colon ; d c, descending colon ; s f, sigmoid flexure or sigmoid colon ; b, rectum ; A, anus. sion, and shortened by dilatation. It occupies the cavity of the belly ; its commencement, at the pylorus, being in. K 3 134 DIGESTION. the right hypochondrium ; its end, at the caecum, in the right iliac fossa, to which the commencement of the large intestine is attached. Part of this terminal portion often occupies the pelvis ; but most of the intervening small in- testine is so free to move, that it may casually occupy almost any part of the abdominal cavity. That upper end of the small intestine which is con- tinuous with the stomach may be distinguished from the remainder by certain differences of arrangement and struc- ture. Starting from the pyloric constriction, it curves in the shape of a horse-shoe around the head of the pancreas ; where it receives the ducts of this gland, and of the liver, and is closely fixed by peritoneum to the posterior wall of the belly. This segment is called the duodenum, from its length being estimated at twelve finger-breadths (about ten inches). It first passes from the pylorus outwards, upwards, and backwards, for about two inches, to the under surface of the right lobe of the liver. This, the first portion, as it is called, is invested by peritoneum on both surfaces, like the adjacent stomach. Its second portion, about three inches long, turns downwards and slightly inwards, in front of the right kidney, to the right side of the third lumbar vertebra ; having a covering of peritoneum on its anterior surface only, while its posterior and left aspect is connected with the adjacent organs by a loose areolar tissue, which concedes to the tube a considerable capacity for distention, and even for movement. The third portion, about five inches in length, passes across the spine below the pancreas, and behind the attached border of the transverse meso-eolon ; the two layers of which partially cover its front, but leave MESENTERY. 135 a narrow uncovered space along the line of their bifurca- tion. Owing to its partial covering of peritoneum, this inferior portion of the duodenum is even less moveable than the preceding. And the position of the pancreas above it, causes its distention chiefly to tell on its inferior surface, which is sometimes so bulged downwards, as to cover the aorta nearly to the division of this vessel into the common iliac arteries. The fixation and curvature of these two last portions of the duodenum probably delay the transit of substances through this intestine, as well as assist that admixture of its alimentary contents with bile and pancreatic juice, to which its attachment seems chiefly to refer. Its use as a means of fixing the stomach, has already been noticed. Its immunity from hernia is explained by its remoteness from all those parts of the abdominal walls, which are sus- ceptible of rupture. The small intestine below the duodenum is loosely at- tached to the posterior wall of the belly, by a double layer of peritoneum, called the mesentery (fiscro?, middle, fV- rspov, intestine). Behind, this mesentery is fixed to the areolar tissue covering the aorta and vena cava, by a line of attachment which, descending from the end of the duodenum to the beginning of the caecum, passes obliquely across the spine from the left to the right side of the lumbar vertebrae. In front, its two layers split to enclose the bowel, around which they become continuous with each other. The distance between its spinal and intestinal borders is from three to five inches, save at its duodenal and caecal ends, where it is suddenly diminished in depth, K4 13S DIGESTION. We may perhaps gain a better idea of the peculiar shape of the mesentery, by figuring it as an obtusely triangular piece of some flattened membranous substance ; fixed to the spine by a truncated apex of some three inches in length, while its broad base, little less than twenty feet from one end to the other, is attached to the intestine, which it is thus the means of plaiting up into a series of convolutions, so as to occupy the least possible space. It is the extreme freedom of movement which such a mode of attachment concedes to the small intestine that gives rise to the convoluted appearance so characteristic of the tube, as seen by laying open the belly in necropsies. The exact configuration of all these convolutions probably never repeats itself, even in the same individual ; being the joint and complex result of the muscular movements of the canal, the nature and amount of its contents, the size of the neighbouring viscera, and the state of the walls of the belly. The effect of dilatation on the small intestine resembles that produced by the same cause in other parts of the alimentary canal ; distention of the tube causing it to extend backwards between the loosely connected layers of the mesentery, with a proportional shortening of this tether. It is usual further to distinguish the small intestine below the duodenum into a jejunum* and ileum]; the * Jejunum, from the jejune or empty state in which it is usually found after death. t Ileum may connote its convolute form (eiAt'or, circumvolvo), its being the most frequent seat of the diseases termed ileus, or its relation to the on MOVEMENTS. 137 former being the upper two fifths, the latter the lower three fifths, of its length. This distinction, though arbi- trary in principle, and vague in application, is too con- Fig. 16. Portion of a bundle of fibre-cells from the muscular coat of the intestine. Magnified 250 diameters. a, nuclei of the fibre-cells. venient to be altogether dispensed with ; the less so, that it tolerably coincides with certain peculiarities in the structure of the mucous membrane, hereafter to be al- luded to. 133 DIGESTION. The muscular coat of the small intestine consigts of fibre-cells (compare Fig. 6) ; the bundles of which (Fig. 16) are arranged in two layers, an outer or longitudinal, and an inner or circular. The first is much the thinner of the two ; constituting a layer, which is often scarcely visible at the mesenteric border of the tube, but is thickened into a more complete stratum at the opposite or free border, where it is firmly united to the peritoneum. Its office is probably to preserve that immobility and inextensibility of the bowel, which are requisite for the proper action of the transverse coat. The circular fibres of this latter form a much stronger and more perfect layer ; and many of their bundles seem to take a slightly oblique * direction, so as to join with others above and below them. Both layers (es- pecially the transverse) are somewhat stronger at the com- mencement of the duodenum. But from the middle of the jejunum, their thickness remains unaltered up to the caecum. Movements of the small intestine. — The normal muscular action of the intestine is usually defined as a peristalsis, or circular constriction (irspi arsXXxo) which, travelling slowly down the bowel, in a direction towards the anus, propels the intestinal contents in a corresponding course. But * Though a spiral arrangement is not distinctly visible, vet it may be noticed that, while the microscopical details hitherto verified no way for- bid such a view, the laws of muscular contraction strongly suggest it. For the effective contraction of muscle always engages it in that line which would traverse the greatest number of its sarcous particles. And it is only by supposing the fibre-cells of the circular layer arranged in spires that we can understand the general advance of contraction at right angles to the axis of its constituent fibre-cells, or explain the extreme slowness of its peristalsis. MOVEMENTS. 139 such a movement has for the most part been rather main- tained as a doctrine, than verified as a fact. The mere thinness of the muscular coat of the bowel would alone suffice to suggest for it a much less vigorous movement than that of the oesophagus or stomach, in which the same coat is from two to five times as thick. Indeed, any such active and continuous peristalsis as that seen in the stomach (p. 99, et seq.) would not allow of a suf- ficient sojourn of the food in the bowels, properly to ac- complish the intestinal share of the digestive process. For even a slow peristalsis of two inches in the minute would traverse the whole intestine in two or three hours ; a speed which would amount to that of a violent and exhaustive diarrhoea in the human subject. More direct evidence^ however, is at our disposal. Sometimes the muscular action of the bowels can be seen and felt through the walls of the belly. In some Polyps, an intermittent, and indeed rhythmic, peristalsis can be seen under the microscope. And even in Man, the borborygmi which sometimes occur in what is substantially good health afford valid evidence of active intestinal movements. While intestinal obstruction, in which both the bowel and the belly are distended and thinned by an accumulation of liquid above the occluded part, allows us to recognise a vigorous progressive contraction engaging the dilated bowel. When the belly of a healthy living animal is laid open by vivisections, injury, or surgical operation, its intestines are generally seen to be at rest. But this state of quies- cence is probably to be explained by the pain and dis- 140 DIGESTION." turbance such injury inflicts, interfering with the always slow and feeble contractions of the bowel. Indeed, there are grounds for asserting that the irritation of the perito- neum, which is involved in such exposure, has a specific influence in relaxing the subjacent muscular coat. It has also been usual to augur the muscular actions of the living intestine from an inspection of the entrails of animals shortly after death. On laying open the belly of a newly killed animal, the intestines are seen lying per- fectly still. But in a short time, those parts of them which are exposed to the air exhibit contractile movements: often irregular, undefinable, and, in a word, rather "vermi- cular " than peristaltic ; often, however, taking a definite course along the bowel toward the rectum ; and always ending in a rigidly contracted and motionless condition of the bowel. But these appearances seem chiefly due to the contact of the air ; and, interesting as they are, they war- rant no conclusions as to those more definite movements which are necessarily executed by the intestines during life. Local irritation of the intestines under the same circum- stances, affords results almost equally inconclusive with the preceding, which indeed they often closely resemble. For example, the mechanical irritation of the bowel produces a contraction which is sometimes immediate, often er pre- ceded by a considerable interval of time ; sometimes local, oftener prolonged below, or even above, the irritated part ; sometimes discontinuous or interrupted. Generally, the contraction outlives, by a considerable interval, the with- drawal of the stimulus; sometimes repeats itself, without the application of any new irritation, as a succession of MUSCULAR MOVEMENTS. 141 waves gradually diminishing in their intensity. Finally, the capacity for such contractions may not only be pre- served by warmth, and by preventing the access of air, but may even be partially restored by the similar treatment of an already exhausted part of the bowel, or may be re- covered during an interval of repose. The mechanical irritation of the exposed intestine of a living animal gives very different results. Compressing the bowel between the fingers produces a local contraction, which lasts a few minutes, and then disappears. Scratching the peritoneal surface usually gives rise to elevations just as local. These elevations seem to begin by a relaxation of the outer or longitudinal muscular layer, afterwards gradually extending to the deeper circular fibres ; which lat- ter often remain excitable to contraction, when the former have lost all irritability. But the mechanical or chemical irritation of the mucous membrane is often quite ineffective in exciting any movement in the muscular wall of the bowel, even when it suffices to provoke downright convul- sions in the hind feet of the animal. The observations of Ludwig and Schwarzenberg upon Dogs, the interior of whose intestines had been rendered accessible by the establishment of artificial jistulce, afford better evidence respecting the normal intestinal movements. By introducing into the bowels balls of wax, attached to -slender lead wires, they verified some important details. They found that the intestinal contents are propelled by a slow continuous peristalsis which has a definite direction towards the rectum. Irritation always provokes a local .contraction. But it only gives rise to peristalsis at definite 142 DIGESTION. times, during the intervals of which the intestine remains at rest. These times have a general connection with the digestive act ; the period of greatest activity being about five hours after a meal ; that of least activity, before it. But peristalsis may also be produced in a starving animal, and an empty tube. And a single continuous irritation, applied at the proper period, generally produces a repeated and intermittent (or rhythmic) peristalsis, in the intervals of which peristalsis irritation is thus incapable of provoking contraction. We may therefore sum up all the foregoing details somewhat as follows. The direct irritation of the organic muscular coat of the intestine excites local contractions ; which are of slower access, feebler power, and longer dura- tion than those which would be excited by the similar irritation of the striated or voluntary muscle. Shortly after death, these contractions evince a general tendency to extend beyond the site of their origin. But during life, this tendency is so modified and regulated, in obedience to the circumstances of the digestive act, as to be either exalted into a definite and effective peristalsis, or suppressed al- together. This peristalsis, the muscular action proper to the bowel, is the chief agent in the propulsion of its con- tents. As regards its energy, we may conjecture that it is restricted to that slow gentle action which would suffice for such a purpose. In character, it is essentially inter- mittent. In respect to its extent, it seems uninterruptedly to traverse long segments of the tube. But it is doubtful whether any contraction proceeds continuously through the whole intestine. And it is probable, that all the more THEORY OF PERISTALSIS. 143 active forms of peristalsis are essentially rhythmic repeat- ing themselves at definite intervals of time. The exact mechanism of this peristalsis remains, how- ever, in obscurity. The slow, feeble, and enduring character of those local contractions which irritation can excite, seems specific to the fibre-cell ; a view which is especially suggested by the remarkable contrast verified in the striped muscular coat of the intestine of the Tench (Cyprinus tinea). But while the phenomena of peristaltic action seem to imply some wider connection of different points, and times, than the mere tissue of the unstriped muscle would suggest or explain, and even to point out the nervous system as the medium of this connection; our ignorance of the ultimate arrangements of the nerves in the muscular coat leaves us in doubt as to the relative shares of nerve and muscle in these peculiar contractions. The contractility of the muscular coat is, doubtless, in- herent to the sarcous substance itself. And its peristalsis is, just as certainly, a complex and thoroughly co-ordinate act, which is placed in at least an indirect dependence upon the cerebro-spinal centre. Indeed, Weber's experiments on the highly excitable intestine of the Tench indicate the medulla oblongata as constituting that segment of this centre through which such a dependence is chiefly brought about. But the exa^t degree in which the various sym- pathetic centres which intervene between the medulla ob- longata and the bowel transmit, modify, or originate, the nervous changes which pass to and fro, remains for the present unknown. It is, however, probable that neither of the two chief intervening ganglia (vertebral and prever- 144 DIGESTIOX. tebral) bound the transmission of an afferent change, or really originate an efferent one. The mucoiis membrane of the small intestine, which is composed of the ordinary elements of a basement mem- brane, an epithelium, and a layer of areolar tissue contain- ing an admixture of muscular fibre-cells, is variously Fig. 17. Small intestine distended and hardened by cdeohol, and laid open to show the valvules conniventes occupying its interior. involuted, so as to complicate the simple flat expanse it would otherwise form by valvules conniventes, tubes, villi. follicles, and racemose or conglobate glands. The valvulce conniventes* are transverse folds, which project from the surface, into the cavity, of the bowel. * So named from their presumably delaying, but conniving at. the pas- sage of the intestinal contents. THE VALVULE CONjNIVEJSTTES. 145 They begin in the second portion of the duodenum, to cease in the lower fifth or sixth of the small intestine. Extreme distention reduces their size, but fails to efface them ; a fact which distinguishes them from all the tem- porary folds of the stomach or intestine. Small and scattered in the duodenum, their size and number reach a maximum in the jejunum, and diminish again in the ileum; in the lower third of which they almost disappear. Each consists of a doubling of mucous membrane ; within which is a process of the subjacent loose areolar tissue, containing vessels, nerves, and laeteals, and capable of being effaced by that artificial emphysema which is pro- ducible by violent inflation of its network. Their direction is nearly transverse to the axis of the tube ; and their extent around it forms one half or three fourths of its circle. Deepest in the middle of this arc (often 3 to 6 lines), they sink at its extremities into the general mu- cous surface. Extreme distention renders them vertical to the intestinal surface. But in the normal dilatation of the tube they are not only exceedingly mobile, but their free margin seems generally to be directed somewhat obliquely up or down the tube. The precise details of their office are imperfectly known. But they obviously increase the mucous membrane of the bowel to a surface twice or thrice as large as that of a corresponding tube with a simply cylindrical wall. And it is also evident that their arrangement transversely to the axis of the canal confers increased effect upon this en- largement : by placing them at right angles to the direc- tion of peristalsis, and therefore to the general course of L 146 DIGESTION. the intestinal contents. This arrangement, combined with their great mobility, enables them to ensure the thorough admixture of all the intestinal contents ; and, by delaying the onward passage of these contents, brings about a greatly increased contact between the mucous surface of the bowel, and the various substances on which it has to act. Tubes. — The other constituents of the mucous mem- brane of the small intestine are so small, that their Fig. 18. Intestinal tubes from the jejunum, as seen in a vertical section. {Magnified 80 diameters.) a, Limitary or basement membrane ; b, nuclei of the columnar cells which line its interior ; c, calibre or cavity of the tube ; d, mouths of the tubes opening into the general cavity of the intestine ; e, blind extremities of the tubes, resting upon the sub-mucous areolar tissue. structure can only be verified by the aid of the mi- croscope. And amongst these minute organs, the tubes (commonly called the follicles of Lieberkuehn) have the first claim ; since they occupy the large as well as the small intestine, and even, in some animals, usurp a portion of INTESTINAL TUBES. 147 the gastric cavity. In Man, they are so numerous, that we may estimate their aggregate surface as from ten to fifteen times that of the general cavity of the bowel into which they open. Each tube is a hollow cylinder, of a length about five times its width ; ending below in a rounded extremity, above by a wider opening ; and composed of a basement membrane and epithelium. The latter is a layer of short columnar cell -growth ; which clothes the whole in- terior of the tubes ; and is continuous, at their upper ends, with the somewhat longer epithelial cells covering the adjacent villi. The calibre or cavity bounded by this epithelium has a diameter about one fourth of the mem- branous tube. Their arrangement so precisely recalls that of the sto- mach-tubes (p. 105) as to require no separate description. The chief interruption to their presence is caused by the villi, follicles, and glands hereafter noticed. Of these three structures, the latter merely encroach by their minute ducts on the space which would otherwise be occupied by tubes. But the two former claim a much larger amount of mucous surface. And since the tubes occupy the in- tervals of the villi (see Figs. 20, 31), the number of these processes strewn over the intestinal surface will necessarily affect that of the tubes. Over the projecting upper parts of the follicles, the tubes are also absent in a corresponding and circular space, which they often surround with a ring of apertures. (Compare Fig. 30.) These tubes secrete a clear, structureless, viscid homo- geneous liquid ; the properties and action of which, how- L 2 148 DIGESTION. ever, remain in part undecided. For the tubes themselves are too minute to permit any satisfactory chemical exa- mination of the liquid in their interior. While the general contents of the bowel form a mixture of nume- rous secretions and ingesta, which are themselves all undergoing a complex and continual metamorphosis. Nothing short of the exclusion of all chyme (including in this word all the gastric juice passed into the intestine from the stomach ) 3 bile, pancreatic juice, and even of the scantier secretions of Brunn's glands, and of the intestinal follicles, would leave that pure residuum which alone would deserve the title, and illustrate the properties, of an " intestinal juice." The nearest approach to these obvious conditions of experiment has been made by Lehmann ; who procured intestinal juice from a fistula consecutive to a hernia in the human subject : where all communication between the segment of intestine yielding this juice, and the liver, stomach, and pancreas, seemed to be excluded by the presence of another fistula higher up, which allowed the efflux of the whole intestinal contents. Frerichs obtained a similar juice from animals in whom he had emptied and enclosed a piece of intestine between two ligatures five hours before death. Here any negative evidence otherwise derivable from the observation is rendered unsafe by the contingencies (shock, inflammation, &c) connected with the vivisection itself. Lastly, Bidder and Schmidt compared the mixture withdrawn from simple fistulse instituted in the bowels of animals, with the purer fluid similarly obtained when the secretions poured out INTESTINAL JUICE. 149 by the biliary and pancreatic ducts had also been diverted externally through fistulous apertures. Here some ad- mixture of gastric juice was, to say the least, almost unavoidable. The purer intestinal juice of such observations is a viscid, transparent, colourless, alkaline liquid, con- taining a scanty admixture of abortive cell growth, but essentially structureless. Its alkalinity is (directly or indirectly) attributable to soda. Its quantity appears to be small. Its composition includes mucus and the ordinary blood-salts; which together form about 2 per cent, of solids, the quantity and quality of which tolerably cor- respond to a specific gravity of about 1010. As regards its physiological action, the intestinal juice appears to convert starch into sugar with great rapidity ; being little (if at all) inferior in this respect to those special agents of this metamorphosis found in the sali- vary glands and the pancreas. But a far more important office is claimed for this secre- tion ; namely, that of dissolving protein-compounds. Bidder and Schmidt have made careful quantitative researches, which show that its solvent powers in this respect are from three to four times greater than those of the gastric juice itself; and that, in the Dog, half the daily albumen of a flesh diet is habitually left untouched by the stomach, to undergo" such a solution in the intestine. And Zander offers what is essentially the same conclusion. The observations of Lehmann and Frerichs, however, concur to state that neither in nor out of the body does the pure intestinal juice dissolve the protein-compounds. L 3 150 DIGESTION. And the especially trustworthy researches of Lehmann in the instance already mentioned are confirmed by the equally negative results of an infusion of intestinal tubes. Allowing for dilution and impurity, such an infusion might fairly be expected, like the parallel infusion of stomach, to repeat the effect of the secretion to which it corresponds. But it possesses no such solvent action whatever. And while a variety of arguments * equally militate against it, the accuracy of Bidder and Schmidt's admirable researches seems quite compatible with the view — rendered probable by many allied considerations — that the gastric juice which is passed into the intestine from the stomach may be con- centrated here by a partial reabsorption of its watery constituent ; just as that gradual neutralisation of its acidity which is also effected in the intestine may well avoid the hurtful results to this secretion of the far more sudden and violent process by which the chemist reverses the na- tural reaction on adding an alkali. Whatever the exact office of the intestinal juice, con- sidering the vast secreting surface by which it is yielded, and its strongly alkaline reaction, it is doubtless one of the chief agents of that process by which the acid reaction possessed by the chyme as it leaves the stomach is neu- tralised in the intestine. Indeed, this alkaline reaction probably has a definite (and complementary) relation to that large quantity of acid which is withdrawn from the blood, in the stomach, to furnish the gastric juice : the liberation of soda or some other alkaline base f appearing * Some of which will be found in the M Cyclopaedia of Anatomy, Suppl. Article Intestine," p. 34S et seq. t Compare p. 120. VESSELS OF TUBES. 151 almost implied in that of hydrochloric acid. But the exact locality of the neutralising process is so far unknown, as that we are left to choose between the alternatives of the intestine on the one hand, or its capillary veins, charged with the acid they have absorbed, on the other. Of these alternatives, the former is much the more probable. The vascular arrangements of the intestinal tubes only differ from those of the stomach-tubes in the fact, that the superficial (and specially absorptive) network of vessels is composed of loops which, save in the neighbourhood of the follicles, are generally more simple than are the cor- Fig. 19. Capillaries occupying the surface of the mucous membrane of the small in- testine ; as seen on examining an injected specimen by reflected light, with a magnifying power of about 50 diameters. a, b, capillaries around the orifices of the intestinal tubes. At a their meshes are more numerous and complex than at b, where they are almost re- duced to single capillaries ; c } calibre or cavity of the intestinal tube. L 4 152 DIGESTION. responding gastric capillaries. They anastomose freely with the capillaries of the adjacent villi ; the venous radi- cles of which join the confluent venous capillaries around the mouths of these tubes, to form small veins that sink vertically through the mucous membrane, to join the sub- mucous plexus of the portal system. Fig. 20. Vertical and longitudinal section of the small intestine in the lower part of the jejunum, showing the general arrangement of its coats. {Magnified 50 diameters.) a, villi ; b< intestinal tubes ; c, submucous areolar tissue ; d, circular fibres of the muscular coat ; e , longitudinal fibres, external to these, covered by peritoneum. Villi. — The inner surface of the small intestine has almost everywhere a texture like that of velvet ; soft, shaggy, yielding readily to pressure, and, on inspection, seen to be composed of innumerable short thread-like VILLI OR PAPILLAE. 153 processes, which are seated vertically on the general wall of the canal. These processes which, as the cause of this velvety appearance, are named villi, might be much better named, in consonance with their form and situation or office, the intestinal or chyliferous papillae. Pig. 21. I Villus from the upper part of the jejunum, as seen in the fasting state. Magnified 140 diameters. a, epithelium of the villus ; b, parenchyma or substance of the same. They begin in the upper part of the duodenum, and in the intervals of the tubes, by bluntly pyramidal and flat- 154 DIGESTION. tened folds, of which the base is about five times as broad as the height (3-^th inch.) In the lower part of the duo- denum they become about twice as long, and half as broad, as the above measurements respectively. In the upper part of the jejunum they reach their greatest number and length ; being planted so closely that their interstices scarcely equal their own width, and ranging from ^th to iVth of an inch in length. Their form is still that of a flattened cone, with a breadth ^th, and a depth y^th, of its height. Henceforth they diminish in length and some- what in number ; though, with this difference, they clothe the whole mucous surface (including the valval ce conni- ventes) completely up to the free edge of the ileo-colic valve. They are, however, necessarily absent over the mouths of tubes ; and are also deficient over the follicles ; on the " agminate " or collected varieties of which they are further reduced to short, blunt, irregular (a, Fig. 31), or even confluent, processes where they occupy the inter- stices of the several adjacent follicles. We have seen that each valvula connivens is a doubled fold of mucous membrane, containing a process of areolar tissue ; and each tube a cylindrical membrane, enclosing a cavity, and imbedded in a scanty fibrous mass. In like manner, each villus may be regarded as a solid process of mucous membrane ; constructed, in accordance with such a definition, of epithelium, basement membrane, fibrous tissue, unstriped muscle, and blood-vessels. In addition to these general constituents of the mucous coat, it specially encloses one or more lacteal or chyliferous vessels. The epithelium (a 3 Figs. 21, 26), is a layer of elon- VESSELS OF THE VILLI. 155 gated cells, in form closely resembling those seen on the ridges between the tubes of the stomach. They are, how- ever, more delicate in consistence, and more conical in shape ; and their contents, even during fasting, darker and more granular. The basement membrane beneath offers a similar resemblance, being closely attached to the vessels and other subjacent structures; from which latter, however, it is occasionally raised as a small bulla or bleb by the dosmose of water. Fig. 22. Vessels of two villi, injected. Magnified 100 diameters. a a, arteries entering the basis of each villus near its centre ; v v, veins seen in the same situation ; c, capillaries lying immediately beneath the limitary membrane ; d, tortuous capillaries occupying the free extremity of one villus ; b, limitary or basement membrane of the villus, denuded of its epithelium. 156 DIGESTION. The blood-vessels are extremely numerous. Small (i~dVo*k in.) arteries, which pass up between the tubes, enter the base of the villus, either singly, or two or three to each villus, in the substance of which they ascend at some distance from the surface, giving off many capillaries, into which their own diminished trunks finally merge at or near the middle of the process. These capillaries, in diameter a trifle larger than blood-discs (youo"^ 1 in«)' branch out immediately beneath the basement mem- brane into a network, which is so dense as to give the whole villus a vivid red colour in injected specimens, and is made up of close meshes, the length of which is usually five or six times their width. They are often wavy or tortuous (6, Fig. 22), especially at the free end of the pro- cess ; a condition in great part attributable to the casual contraction of its muscular layer. The veins come from this network by the union of the capillaries in the upper half of the villus to form two or more branches ; which, wider and more superficial than the corresponding arteries, become confluent in a single vein passing vertically down- wards to join the venous plexus that surrounds the mouths of the tubes. The latter plexus also communicates with that of the villus through the other capillaries at its base. by means of which the two networks might almost be said to merge into each other. The granular substance of the villus presents no definite structure beyond an occasional faint striatum, which rarely approaches a fibrous character. Mixed with this striation. however, are seen delicate cytoblasts, of which the larger attain the size of coloured blood-corpuscles (6, Figs. 21, 23. LACTEALS OF VILLI. 157 24), while the smaller range down to granules by increas- ing minuteness. They communicate to the whole villus a mottled and granular aspect, which obscures all the other structures beneath the basement membrane. Fig. 23. Two villi, denuded of epithelium, with the lacteal vessel in their interior. From the Calf. Magnified 350 diameters. {After Koelliker.) a, limitary membrane of the villus ; b, matrix or basis of the same ; c, dilated blind extremity of the central lacteal ; d, trunk of the same. The lacteals, or chyliferous vessels, appear to commence within these processes by a single tube, which begins near 158 DIGESTION. the point of each villus by a blind (and often somewhat dilated) extremity, and passes down its axis to open into the network of these vessels occupying the submucous areolar tissue. The diameter of the central canal is, in Man, about one sixth that of the villus itself : a proportion Fig. 24. Villus denuded of epithelium, treated with acetic ac kitten. Magnified 350 diameters, a, outline of the villus ; b\ nuclei beneath this ; c. nuclei of the unstriped muscle ; d, roundish nuclei in the centre of the villus. often doubled at the terminal dilatation. It has a tinct wall of exceedingly fine (and apparently structure! membrane. Occasionally, the tube seems to bifurcate as MUSCLE OF VILLI. 159 it ascends the villus. But this appearance (and still more that of the network described by many observers) is probably an optical illusion ; save perhaps in the longer and more conical villi. The muscular substratum of the villus is a thin hollow cone, which in form closely follows the general outline of the process itself. Hence, from whatever side it may be examined, it is visible as a double layer ; which is placed immediately on both sides of the central lacteal, and is surrounded by most of the vessels, as well as by much of the granular basis. The action of this contractile apparatus is unknown. Doubtless an offshoot of that general expanse of unstriped muscle which pervades the mucous membrane of the whole alimentary canal, it probably has a function analo- gous to that of this layer elsewhere ; and, indeed, co- ordinate with it. That this function is chiefly related to the static or passive mechanism of the mucous coat, has been already (p. 136) conjectured. The little we know of the action of -the same element in the skin confirms this view. But its anatomical relations in the villus to the blind and dilated end of the central lacteal — of which it thus forms a muscular or contractile envelope — have raised the suspicion, that it propels the chyle contained in this canal. Whether such a process really obtains must be deter- mined by future researches; which ought especially to notice the connection of this muscular layer with that of the mucous membrane generally, Meanwhile we may notice that, as Koelliker justly remarks, the exercise of 180 DIGESTION. an active force of propulsion by these longitudinal fibres would imply their alternate contraction and relaxation. To this we may add, that from analogy it is probable that an irritation of the sympathetic might excite the latter of these changes, just as the stimulus of distention or stretching might well bring about the former. But nothing short of such a remittent and alternate action would destroy the claims of the absorptive act itself to be considered the chief force which propels the chyle : since, in any other case, the muscular apparatus would only limit and remove that distention of the lacteal, which absorption had previously effected against an opposing mus- cular contraction. It is thus left in doubt how far this apparatus originates the mechanical force which propels the chyle ; how far it merely controls, regulates, or transfers, an independent and more recondite force at certain in- tervals of time. It has indeed been attempted to verify the action of this delicate muscular apparatus during life in some of the domestic animals. Grruby and Delafomi are confirmed by Bruecke and Koelliker in their observation, under these circumstances, of an alternate shortening: and lengthening of the villus : a change so rapid and marked, as to be doubtless due to a corresponding contraction and re- laxation of these its unstriped fibres. But the phenomena of such vivisections cannot safely be accepted as those of the natural state. Such a caution is still more applicable to the contractions by which the villi share in that irregular intestinal move- ment — a kind of rigor mortis — already (p. 139) described. COXTKACTIOXS OF VILLI. 161 Exposed immediately after death, they gradually become shorter and wider ; while their surface is usually thrown into transverse wrinkles and folds. Transmitted light shows these folds to consist of the epithelial layer, which has separated from the basement membrane at the pro- jections between adjacent wrinkles. Sometimes the ad- Fig. 25. |M»»»«:sH5iji;i III*; • s.:::M !"'•' l m Villi contracted and shortened so as to offer circular or transverse wrinkles. From the small intestine of the Dog shortly after death. Magnified 100 diameters ; and examined by reflected light. hesion of the same layer to the free end of the villus forms, at this point, a kind of shallow funnel, which is bounded by the neighbouring separated cells. In other instances, the free end of the villus is withdrawn from its M 162 DIGESTION. epithelial investment by the contraction of its muscular layer so uniformly, as to leave the whole of the cell- growth covering this part uninjured, smooth, and empty, like the finger of a glove. Often, however, a few cells are here and there detached. Fig. 26. B Similar villi as seen by transmitted light. The villus on the left has partially withdrawn by contraction from its investing epithelium, wku thus left entire, like the finger of a glove. a, epithelium of the villus; b, granular matrix or substance of the same. All these appearances are obviously due to a contraction of the muscular constituent of the villus within its more or less separated cell-growth. And the movements which VILLI DURING DIGESTION. 163 accompany their occurrence often resemble those seen during life : consisting of shortening or elongation, some- times complicated by lateral displacements. Their dura- tion rarely exceeds a few minutes. During the digestive act, the villi undergo notable changes. They receive a copious and sudden afflux of blood ; become larger and softer ; and acquire a greater opacity, which renders them whiter by reflected, darker by transmitted, light. The cytoblasts occupying their interior are also greatly increased in number and distinctness. And, lastly, after the ingestion of any food which includes the ordinary fatty ingredient of a mixed diet, a part of this alimentary constituent is also found in their interior. The first step towards this absorption of fatty matter into the villus consists in an entry into its epithelial in- vestment : each columnar cell of which is gradually rilled by a large oil-globule. The change first involves scattered cells; and, by rendering them more refractile, causes a curious contrast of bright spots and darker intervals (Fig. 27) on the outer surface of the villus. Gradually, how- ever, the whole of this surface shares in the change. The next step consists in the minute subdivision of the single oil-globule now contained in the epithelial cell. The details of this (quasi emulsive) process are unknown : but its result is to give the cell a dark granular appear- ance, which a close inspection can distinguish as due to separate fatty molecules of great minuteness. These mo- lecules are next found in the granular substance of the villus itself, chiefly near its surface and apex. From thence they soon penetrate the central lacteal trunk ; 164 DIGESTION. which they sometimes define as a slender column of dark fatty granules. That this process is in part a physical imbibition, can scarcely be doubted. Matteucci and Valentin have proved that diffusion occurs between a dilute alkaline solution, and Fig. 27. Villus of the Dog about two hours after feeding : showing the entry of fat into scattered epithelia on its surface. Magnified about 400 diameters. «, a, outline of the villus, formed by epitlielia with their ordinary contents: b, b, epithelia rendered bright and refractile by their fatty contents. a faintly alkaline fatty emulsion, when separated by tissues like those of an animal's bladder. And the circumstances actually present in the villus are more favourable to such a transit than those attending the experiments of these oh- ABSORPTION OF FAT. 16o servers. For the alkalinity of the lymph and blood some- times exceeds that of the solution they used. And the scarcely conceivable degree in which the tenuity of the cell- wall of the villus exceeds that of such thick and compound membranes as those which form the diffusive partition in these experiments, would enormously favour the transit of the separated fluids. Furthermore, those independent forces which probably aid the continuous movement of the chyle, constitute an additional advantage possessed by the living villus over the inert endosmometer. On the other hand, the absorption of fatty matters im- plies other and more recondite processes. For the fatty molecules of the chyle have reactions which prove them to be still oily, and not saponified, as are the substances transferred through the membranes used in the diffusive experiments alluded to. And while the position of the capillary plexus, and the rapidity and bulk of its stream, render it probable that any merely diffusive action would dis- proportionately affect the blood — which indeed, as already stated, is often more alkaline than the chyle — the reverse seems to be the case ; a larger quantity of fat being taken up by the lacteals than by the bloodvessels. The above view is further confirmed by the effects of violent inflam- mation, and of great interference with the bloodvessels, in preventing the formation of chyle : as well as by that strict natural limit which seems to check all further ab sorption of fatty matter : — so that, when its amount in any part of the intestine exceeds what the villi can take up, the residue is passed on to the succeeding parts ; failing absorp- tion by which, it is discharged in the excrements. 31 3 166 DIGESTIOX. Follicles* — The structures to which it is desirable to restrict this term are essentially closed sacs, analogous to those represented in the stomach by the lenticular glands. (See p. 109.) They pervade the whole intestinal canal in two forms : solitary and agminate follicles ; the latter being, as their name implies, little more than aggregations or clusters of the former. The agminate f follicles are generally scattered over the small intestines in about twenty clusters. Their shape is commonly an ellipse, in length about twice its width. They are situated along the free margin of the bowel, opposite the attachment of its mesentery ; in an extent usually corresponding to its lower three-fifths, or the ileum, of which they may be regarded as characteristic. But they are sometimes sparingly scattered throughout the lower part of the jejunum also; and, more rarely, extend up- wards through this segment even to the duodenum. In such cases their number is from twice to thrice that given above. Still, amid all their variations of number, extent* and size, they retain a predominant relation with the lower end of the ileum. For they are not only both larger and more numerous here ; but while, elsewhere, their length is rarely more than an inch, the immediate neighbourhood * The etymology of this word not only permits its application to these closed sacs, but suggests its restriction to them, and its abandonment as a designation for the tubes (p. 145.). f Oftener termed Peycrs or Peycrian patches ; a name which probably clings to them, in consequence of its uniting all the disadvantages of uu- couthness, irrelevance, and (so far as it awards their discovery to an ana- tomist who was anticipated therein by our own countryman. Grew) inaccuracy. AGMINATE FOLLICLES. 1G7 of the ileo-caecal valve is often occupied by an irregular cluster, with a length ranging from two to four inches,* and a width which amounts to two-thirds or three-fourths the circumference of the bowel. The surface of such a cluster, which is raised above the general mucous surface, is occupied by a number of ir- regular shallow depressions (6, Fig. 28) at tolerably equal Agminate follicles as seen by reflected light. Magnified 4 diameters. Koelliker. ) (After a, general mucous surface with villi ; b, depressions leading to the several follicles ; c, intervals between them, covered by small villi. distances from each other. The floors of these depressions or pits are formed by a corresponding number of grains, of about the size of a millet-seed; the greater thickness M 4 168 DIGESTIOX. and opacity of which, as contrasted with the adjoining in- testinal walls, often renders the cluster distinctly visible by transmitted light, even when viewed through the peri- toneal and muscular coats. Each cluster contains from 20 to 200 follicles, according to its size. The pits over the several follicles do not lead Fig. 29. Agminate follicles in a state of distention. Magnified about 5 diav. {After Boehm.) a, general mucous surface of the ileum ; b, b, opaque grains corresponding to the several follicles. to apertures, but end on a smooth surface, of which the convexity diminishes their own depth. In their inter are found tubes and villi, with somewhat modified charao FOLLICLES. 169 ters. For the tubes immediately around each pit have a circular arrangement, so as to form a ring of ten to twenty apertures, with a very characteristic appearance, suggestive of pressure or distention. The adjacent villi also often appear to radiate from the centre of the pit. And both they, and the villi more equi-distant from the neighbouring follicles, differ from the villi seen on those parts of the Fie. 30. Portion of a cluster of agminate follicles. a, a, follicles encircled by apertures of the intestinal tubes in the form of a ring; b, short and obtuse villi, occupying the intervals of the follicles ; c, apertures of intestinal tubes, opening irregularly in these intervals. intestine which are unoccupied by these clusters, in being fewer, shorter, of more regular form, and often confluent at their bases. (Figs. 30, 31.) Careful dissection and examination will show that each follicle is a closed sac ; with a roundish form, save where its conical apex is directed towards the general mucous surface ; and a diameter from one- to three-fifths of an inch. Its base rests on tlje muscular coat, attached by an areolar tissue like that of the loose sub-mucous network in which the follicle is imbedded by the greater part of its depth. Its bluntly conical summit ascends between the lower 170 DIGESTIOX. ends of the adjacent tubes ; and terminates, below their middle, at the floor of the pit into which the general mucous surface is depressed here. The exceedingly delicate layer of tissue intervening between the follicle and the intestinal cavity consists of a small quantity of an indis- tinctly fibrous structure, which encloses some capillaries, Fig. 31. ' " "-'SM Plan of an agminate follicle, as seen by a vertical section. Magnified 40 diameters. a, short and conical villi surrounding the follicle ; b, intestinal tubes in the same situation ; c, muscular stratum of the mucous membrane ; d. sub- mucous areolar tissue, in which the follicle is chiefly situated : e, circular layer of the muscular coat; f longitudinal layer of the same ; g. peritoneal coat; h, follicle enclosing nuclear contents; /, apex of the follicle pro- jecting into the cavity of the bowel. and seems to be covered by the ordinary columnar epithe- lium. It is so easily ruptured by disease, putrefaction, and mechanical violence, that many have regarded the VESSELS OF FOLLICLES. ]71 follicle as opening here by a permanent orifice, or as easily acquiring one by a natural dehiscence. The capsule of the follicle is a structure which differs from basement membrane in being much thicker, and in possessing an indistinctly fibrous texture. Its smooth outer surface exhibits elastic fibres, and is attached by areolar tissue to the surrounding submucous structures. The vessels offer a peculiar arrangement. The small arteries of the submucous plexus send branches among the several follicles of each cluster, so as to form a network of minute arteries, which chiefly occupy a horizontal plane. These break up into numerous capillaries, which surround the membranous capsule with an irregular network, de- ficient only at the apex by which the follicle projects into the intestine; where its long loops, bending back upon themselves, leave a central space uncovered by vessels. And Frei has shown that a similar arrangement extends throughout the whole remaining depth of the follicle ; the capsule being everywhere penetrated by a number of minute capillaries (Fig. 32), which leave the former net- work at right angles, and reach nearly to the centre of the follicle before looping back to its exterior. The uppermost of these capillaries unite to form the radicles of one or two veins of thrice their own diameter, which descend vertically through the follicle, receiving no further branches until they reach the submucous plexus. The contents of the follicle form a pale, greyish, opalescent pulp; which is composed of a proteinous substance closely akin to albumen, and reveals, to a careful examination, a fluid mingled with cells. The latter, of very variable character, are reducible 172 DIGESTIOX. to two kinds: cells indicative of the several stages by which blood-corpuscles, apparently of casual extravasation, seem to recede towards solution on the one hand ; and a multiform and specific cell-growth, on the other. In this growth Koelliker has found traces of an endogenous mul- Fiff. 32. Vessels of the three agminate follicles of the Babbit ; as seen by a horizon- tal section, at about the raid elk of their height, {After Koelliker ; from an injection by Frei.) a, a, a, minute vessels surrounding the capsule of the agminate follicles b, b, b, delicate capillary loops penetrating their interior, and bending back from c, c, c, the centres of the follicles. tiplication of cells ; as well as of the splitting of the wall of a cytoblast, so as to isolate, and remove, an outer cell membrane. In other cases, he has noticed what seems to be a converse process of regress or decay, in the form OFFICE OF FOLLICLES. 173 of large cells filled with angular corpuscles, which are apparently produced from the ordinary cells of the pulp, and lose their nuclei prior to a complete disappearance. The exact function of these follicles is unknown. But, composed as they are of innumerable cells, in contact with a large vascular surface, it is in the reaction of these minute agents on the rich and copious nutritional fluid ex- suded from the adjacent blood, that we may presumably find their chief office. And the various stages of cell-life simultaneously present would indicate that the cells have the power not merely of selecting and appropriating ma- terials, but of producing them ; and that by a process of metamorphosis which, directly or indirectly, consumes their own tissue, and thus involves their own decay and removal. In this respect the agminate follicles may be regarded as having a structure and function akin to that of the vascular glands ; and as selecting from their nutritional fluid certain constituents, which, after undergoing certain changes in their interior, are returned thence into the general current of the blood. But the relation of these follicles to the intestinal cavity complicates this view by suggesting a correspond- ing and two-fold modification. The materials on which their enclosed cells act may possibly be derived from the various contents of the bowel, as well as from the blood. Their products may also be excreted by the intestine, as well as returned into the closed system of the blood- vessels. And since the degree in which the intestine forms such a channel of ingress and egress for the follicles must depend chiefly on the directness and efficiency of its com- 1 74 DIGESTION. munication with the follicular cavities, it is to be presumed that any such close contiguity as obtains in the human sub- ject would permit an efficient transudation of this two-fold kind. But where, as in the Calf, the cavities of the intes- tine and of some of these follicles are separated by a thick "compound membrane, the transit in either direction is pro- bably reduced to a very small amount. The follicles seem also to be related to a third structure : namely, to the lacteal system. That analogy of the follicle to the vascular gland above noticed, is far surpassed by the closer resemblance between the follicles of the intestine and those of the lymphatic glands ; both enclosing vessels, and a cell-growth, within the limitary membrane which forms their wall. And though neither have lacteals yet been verified within the intestinal follicles, nor any direct communication found between their cavities and those of the neighbouring lacteals, yet it seems certain, both that these vessels occupy the agminate follicles in numbers quite disproportionate to the few and small villi present here, and that they are arranged in the closest proximity with the follicular contents. How far these follicles really share the nature and office of lymphatic glands is, however, still in doubt. In any case, their very variable number and size indicates that (like the similar structures of the tonsils and stomach) their function is probably one which can be vicariously discharged by other allied organs. From their number and size, too, we may conjecture that their quantitative influence on the chemistry of the organism is not great. Their changes in health and disease confirm those relations to the vascular and DUODENAL GLANDS. 175 lymphatic systems above deduced for them. Their swollen condition during digestion may be attributed equally to the increase of intestinal absorption, and to the afflux of blood, then occurring. Their swelling during the drain of cholera may perhaps also claim the latter of these causes. And finally, that close parallel between the disease of these follicles and of the neighbouring mesenteric glands, which is seen in phthisis and typhoid fever, confirms the analogy between the two structures. The " solitary " follicles are exactly like those grouped to form the " agminate" save in their not being surrounded by a circle of orifices of tubes, and in their often sustaining villi of ordinary size and shape. They are sometimes difficult to find, in consequence of their undistended state ; an explanation which probably applies to those cases in which they are alleged to be altogether absent. Whether that excessive development of them which is also some- times seen must be regarded as really morbid, or as a mere casualty, or even as a kind of collective hypertrophy, re- mains for the present doubtful. In the large intestine, they are not only more numerous, but attain a greater size ; and are more deeply imbedded in the submucous areolar tissue. The form of the pit or fossa which overlies their highest part is also somewhat modified, widening as it leaves the general mucous surface, to pass downwards between the intestinal tubes, and to end, near their ex- tremities, on the bulging surface of the follicle. Duodenal, or Brunn's Glands. — The remaining consti- tuent of the compound intestinal membrane is limited to a very small fraction of the canal : namely, to the duo- M6 DIGESTION. denum ; of which segment it is thus, as it were, the cha- racteristic structure. The duodenal or racemose glands are small roundish granules, which occupy the submucous areolar tissue ; and open by a duct, which passes through the mucous membrane to the general intestinal cavity. Immediately below the pylorus, they have a diameter of 1 to 1J lines; and are so close to each other, as to form a kind of layer around the bowel. Lower down, they dwindle to half or one-third this size ; at the same time that they gradually become more sparing and scattered, until, in the inferior transverse position of the duodenum, they finally cease altogether. The duct of each opens on the free surface of the bowel, mostly in the depressions which separate the rudimentary villi present here. The valvules conniventes are not per- meated by them. Elsewhere, however, the general mucous surface is studded pretty uniformly by their apertures, of which two or more sometimes closely adjoin each other. Their minute structure is precisely like that of the conglo- bate salivary glands already noticed (p. 73). Their lobules, aggregated into a mass by an envelope of areolar tissue, are shown by further dissection to consist of smaller ones, which resemble a bunch of grapes (Fig. 33), and consti- tute the acini of the gland. These acini, which average 1 -300th of an inch in diameter, are the irregularly polyhe- dral (rather than spherical) dilatations (Fig. 34.) which end in cylindrical tubes of about two-thirds this size. The re- peated unions of these tubes converge into the duct; the columnar cell-growth lining which near its intestinal aper- ture merges into the flat, small, tessellated epithelium DUODENAL GLANDS. 177 specific to such glands in its ramifications. They secrete a viscid, structureless mucus, with an alkaline reaction. • As respects their office, their secretion undoubtedly has the Fig. 33. Brunns or duodenal gland, as seen in a vertical section of the duodenum. Magnified 40 diameters. a, intestinal tubes ; b, muscular stratum of the mucous membrane ; c, c, acini of the duodenal gland which occupies the submucous areolar tissue ; d, transverse layer of the muscular coat ; e, longitudinal layer of the mus- cular coat ; /, peritoneal tunic of the bowel. capacity of converting starch into sugar. Its other pro- perties remain undecided, the structural analogies which suggest for it salivary and pancreatic functions leaving it N 178 DIGESTION. very doubtful whether it can be regarded as akin to the intestinal juice. Fig. 34. Diagram of two ducts of a lobule. a, Efferent duct of lobule ; b, side branches ; c, vesicles in situ ; d, the same separated, and the duct unfolded. In addition to the secretions of the foregoing structures, the small intestine receives, at its upper part, the copious products of two large and important accessory organs : the pancreas, and the liver. The pancreas (pa, Fig. 35) is a soft white gland, weigh- ing about 5 oz., measuring about 5 cubic inches, and placed in the concavity of the duodenum, nearly at the centre of whose arch it opens by an orifice common to it and the bile-duct. In its minute anatomy it so closely corresponds to Brunn's and the salivary glands already described, as to require no separate description. The arrangement of its lobes ; the softness, scantiness, and laxity of their areolar envelopes ; the anatomy of its duct ; and the distribution of its vessels ; — of which the veins join the postal system — are features of subordinate import. Its secretion, conjecturally amounting to about half a pint daily in the human subject, is a structureless, clear, colourless, viscid liquid, with a specific gravity of about 1030, and a large solid content which dried at a heat of PAXCEEATIC JUICE. 170 120° F., forms about one tenth of its total quantity. It appears to be poured out in largest quantity about two hours after a meal, and to intermit in the fasting state. Chemically, it has a strong alkaline reaction, which appears chiefly due to soda ; and its inorganic constituents, which constitute about one-tenth of the total solids, include a large (three-fourths) ingredient of chloride of sodium, with Piff. d a Shape and arrangement of the duodenum and pancreas, eis seen on raising the stomach and liver. st, stomach ; p, its pyloric valve ; I, liver ; g, gall-bladder ; d, duodenum ; 1, 2, 3, its first, second, and third portions ; pa, pancreas ; h, head of the pancreas, by which it is received into the concavity of the duodenum ; sp, spleen ; a, aorta, behind the inferior transverse portion of the duodenum ; sm, the superior mesenteric artery, in front of it. small quantities of soda, lime, magnesia, and iron. Its organic residue, which is soluble in water but precipi- table by alcohol, consists of a substance with an ultimate composition allied to albumen, and contains a certain quantity of free carbonate of lime. It rapidly undergoes spontaneous decomposition at ordinary temperatures ; a cir- N '2 ISO DIGESTION. cumstance which distinguishes it from pepsine (p. 120) and ptyalin (p. 80), to which it might otherwise be regarded as offering close analogies. Its exact share in the digestive process is, in some respects, still undecided ; not only as regards those compli- cations of its effects suggested by the situation in which its secretion is admixed with the other contents of the digestive canal, but even as regards those more specific influences on the chief constituents (p. 52) of the food which experiment might be expected to verify. 1. Its action on starch is the most incontestable of these effects. The secretion and infusion of the gland convert starch into sugar with a rapidity and energy equalling the similar conversion operated by saliva; which latter, indeed, the pancreatic juice may be regarded as surpass- ing, in the fact that no admixture (p. 84) of any other secretion seems necessary to bring about this maximum of energy. It must further be noticed that the change occurs even at low (64° F.) temperatures, and is utterly unac- companied by any trace of putrefaction. 2. Its action on fat, though perhaps in some respects more questionable, has been shown by the researches of Bernard to constitute another important branch of its office. Out of the body, the pancreatic juice separates most of the neutral fats into their acids and bases. In the body, how- ever, as is seen in the neutral and combined state of the fatty matters of the chyle, this change seems not to occur ; being probably prevented by the admixture of gastric juice, as it is certainly capable of being prevented by the presence of free lactic or other acid. But a more impor- ACTION OF PAXCREATIC JUICE. 181 tant change effected by this gland in the fat of the chyle has been deduced by Bernard, from his admirable researches on the pancreatic juice. He has shown conclusively, that the admixture of this secretion to fat converts it into an emulsion of the most complete and intimate kind, such as does not separate again, even on protracted standing ; and thus amounts to a minute division, going far to account for the remarkable change of the fat which enters the villus (p. 163) during digestion. This emulsifying process, which may be seen out of the body, also takes place within the canal ; being bounded above by the entry of the pancreatic duct, in animals killed at a proper interval after the diges- tion of fatty food ; or deficient altogether when the duct is either obstructed, or diverted from the intestine. The latter contingency had, indeed, been long foreshadowed by the occasional results of disease ; in which large or pro- found lesions of the pancreas had occasionally been found associated with such a complete failure in the absorption of alimentary fats, as allowed it to be passed unchanged, and in large quantities, with the stools. 3. Its action on the various protein-compounds has not yet been established. But there are striking facts which vaguely indicate some important relation between this se- cretion and these constituents of the food. It is true that the fresh pancreatic juice, and the infusion of the gland- substance, in all stages of digestion, are quite incapable of dissolving albumen. But both the secretion and infusion of the gland acquire this power so rapidly in their progress towards decomposition, and in advanced stages of this pro- cess, dissolve albumen in a quantity and rapidity so closely N 3 182 DIGESTION. akin to the copious and energetic solution of albumen effected by the secretion and infusion of the stomach, as to promise the discovery of some valuable physiological clue to both these processes of solution as the reward of future research. The more so that (as Dr. Corvisart has pointed out) the resulting solution has many of the reactions of peptone ; and that the solution of albumen in this man- ner is (as I have shown) specific to the pancreas, in the sense of being utterly absent even from those salivary organs (parotid, submaxillary, sublingual, &c.) which are in other respects most closely allied to the pancreas both in structure and function. Nevertheless, the distinction between the putrid and unstable solution into which the secretion and infusion of decomposing pancreas convert albumen, and the perfectly fresh and stable peptone of the gastric juice, as well as the contrast of those circumstances which conditionate the act of solution itself, justify our denying the claims of the pancreas to rank as a solvent of albumen and other protein-compounds in the healthy digestion of the living body ; until it is shown how these circumstances, in themselves generally so injurious to health and Life, and therefore conclusive against the normal character of the act which involves them, are modified or prevented during the ordinary action of the pancreas as an agent in the digestive process. The liver (I, Figs. 12, 35, 36), a large organ which occu- pies the upper part of the abdominal cavitj 7 , being suspended from the diaphragm so as to overlap the stomach, duode- num, and first bend of the colon, is characterised by having THE LIVES. 183 a two-fold supply of blood : one, the ordinary arterial fluid, which is distributed to it (h, Fig. 12) in a quantity so small Ffc 36. The under or concave surface of the liver. Nos. 1, 1, the anterior border ; 2, 2, the posterior border; 3, the notch upon the anterior border; 4, 4, the longitudinal fissure containing the fibrous cord of the round ligament ; 5, the fissure for the ductus venosus ; 6, the transverse fissure ; 7, the point of union of the three fissures, the longitudinal, the transverse, and that for the ductus venosus ; 9, the portal vein in the transverse fissure, the hepatic artery, and the trunk of the ductus communis choledochus ; 11, the cystic duct; 12, the gall-bladder; 13, 13, the inferior vena cava passing through its fissure ; 14, the cord of the ductus venosus, joining the inferior cava as that vessel emerges from the substance of the liver; 15, part of the oval space on the posterior border of the liver; 16, the right lobe; 17, the left lobe; 18, the lobulus quadratus; 19, the pons hepatis; 20, the lobus Spigelii; 21, the lobus caudatus. as probably does but suffice to supply the branches of its duct ; the other, in much larger amount, those venous con- tents of the portal trunk upon which it operates in the discharge of its function. The latter channel is the con- flux of two veins : one of which brings the venous blood N 4 184 DIGESTION. furnished by the spleen ; while the other contributes that much larger, but more irregular and fluctuating quantity of blcod 5 which is derived from the veins of the intestines A transverse section of a large portal canal and its vessels. The lobules are in a steite of general congestion, their central portions being more congested than their marginal portions. — Fram Kieman's paper. No. 1, Superficial lobules forming the parietes o_f the canal. In some the intralobular vein does not extend to the surface of the canal ; this ap- pearance depends upon the direction in which the incision is made. 2. The portal vein. 3, Vaginal branches arising from the vein and dividing into interlobular branches which enter the interlobular spaces. 4, Hepatic duct. It is seen to give off vaginal branches which divide into interlo- bular ducts, the latter enter the interlobular spaces. 5, The hepatic ar- tery ; it is seen giving off vaginal branches which divide into interlobular branches, and the latter enter the spaces with the branches of the portal vein and hepatic duct., 6, Three interlobular vessels, a duct, vein, and artery, entering each interlobular space. 7, A part of the vaginal plexus. 8, 8, Glisson's capsule, which completely surrounds the vessels. and the stomach, and is charged with the various substances newly absorbed from the alimentary canal. (Fig. 48, p. 224.") THE LIVER. 185 The liver is a brownish red mass, which averages a bulk of about 90 cubic inches, a weight of about 4 lbs., and a specific gravity of about 1070. To its under surface is attached a gall-bladder or reservoir for its secretion: as are also the main trunks of the vessels, nerves, and duct which ramify in its interior. The markings and irregu- larities connected with these have received special names (Fig. 36), of interest chiefly to descriptive anatomy. Fig. 38. A longitudinal section of a sublobular vein. Nos. 1, 1, longitudinal sections of lobules, presenting a foliated appear- ance. 2, 2, superficial lobules terminating by a flat extremity upon the sur- face of the liver ; 3, 3, the capsular surface of a lobule ; 4, the bases of the lobules seen through the coats of the vein and forming the canal in which the sublobular vein is contained ; 5, the intralobular vein commencing by minute venules at a short distance from the capsular surface of the lobule ; 6, the intralobular vein of a superficial lobule commencing directly from the surface ; 7, the openings of the intralobular veins which issue from the centre of the base of each lobule; 8, the interlobular fissures seen through the coats of the sublobular vein ; 9, interlobular spaces. The " capsule of Grlisson " is an investment of fibrous or connective tissue, which contains little of the yellow or 186 DIGESTIOX. elastic element, and is covered by peritoneum of the ordin- ary structure. It sends in processes, which unite with the Fig. 39. Longitudinal section of a small portal vein and canal. — After Kiernan. a, Portions of the canal from which the vein is removed to show that it is surrounded by lobules similar to those upon the external surface of the liver, b, That side of the portal vein which is in contact with the canal. c, That side of the vein which is separated from the canal by the hepatic artery and duct, by the capsule of Grlisson surrounding them, and by the vaginal plexus, d, The internal surface of the portal vein, through which is seen the outline of the lobules, and the openings of the interlobular veins which correspond with the interlobular spaces. Upon the opposite side (c) the portal vein being separated from the portal canal there are no inter- lobular veins, c, The openings of smaller portal veins, f Vaginal veins giving off branches in the portal canal and forming a plexus, g, h, The hepatic artery and duct giving off vaginal branches. similar tissue interspersed through the hepatic substance, as a sparing sheath to the vessels and ducts. The portal vein ramifies in the liver by repeated bifur- HEPATIC LOBULES. 187 cations, each of which is accompanied by a branch of the duct and artery ; all three vessels being enveloped in a Fiff. 40. Lobules, showing the portal venous plexus. — After Kiernetn. a a, Interlobular veins, forming venous circles, which, when examined with a higher power, are seen to be vascular plexuses, occupying the inter- lobular fissure, b. The lobular venous plexus enclosing circular and ovoid spaces, the " acini " of Malpighi. c, The intralobular vein, collecting the blood from the lobular venous plexus. common sheath of connective tissue, thence named the portal canal. The smallest branches of all three occupy the intervals of the hepatic lobules : — small grains of liver-substance, which are seen on the outer surface of the organ, appearing through the capsule, as roundish or polyhedral masses about ^V i ncn i n diameter ; and which extend through its whole interior, being isolated from each other by common partitions of connective tissue, the sparing stroma of these vessels (Figs. 37, 38, 39). 188 DIGESTION. The small branches of the portal vein between these lobules {interlobular, a, Fig. 40) break up into a capil- Fig. 41. Network of hepatic cells with its capillaries, magnified 3o0 diameters. the Pig. — After Koellikt r. lary network ; the vessels of which, of large (-^oVo inch | size, and close proximity to each other, converge to unite in a vein (intralobular, Xos. 5, 6, Fig. 38, and c 9 Fig 40), which occupies the axis of the lobule, to the several projections of which it gives one or two short branches. These intralobular veins open into larger veins (sublobular\ upon which they are mostly seated by their bases (Fig. 38), and which converge to form, by their succes- sive unions, the hepatic vein; which joins the vena a and thus empties its blood into the right side of the heart. HEPATIC CELL-GKOWTH. 189 The interstices of this capillary network appear to be occupied exclusively by a mass of cells (Figs. 41, 42.); Fig. 42. Vciw, from nature, of the network of hematic cells, and smallest interlobular ducts from the human subject. Diagram of the connection between the cells and ducts. After Koelliker. Magnified 350 diameters. a, Interlobular duct, b, The hepatic cells, c, Interspaces corresponding to capillaries. which constitute the parenchyma of the liver, and are so moulded around the walls of the capillaries, as to fill up their meshes, each cell being in contact with capillaries by some part of its surface. The cells themselves, about -py^o-th inch in diameter, are polyhedral or angular (often some- what flattened) as though from close packing ; they are bounded by a distinct wall, and contain a nucleus, (usually enclosing one or more nucleoli), and a viscid yellowish granular liquid, in appearance closely resembling bile. The 190 DIGESTION. fatty granules or globules, and the yellow colouring matters also often found in these cells, seem to be mainly attribut- able, to disease or commencing decomposition. The relation of these cells to those minute interlobular canals (a, Fig. 42) which form the apparent commencements of the hepatic duct, still remains in obscurity. On the whole, the opinion of Koelliker — that the latter abut directly on the outermost of the hepatic cells, the rows of which take somewhat of the radiating arrangement of the capillaries whose meshes they fill — seems to be the most probable. The canals are lined by a small polygonal epithelium ; which in arrangement, shape, size, nucleus, and contents, somewhat resembles that of the salivary glands. (Fig. 3, p. 75.) In passing from the smaller to the larger of these interlobular bile-ducts, their transparent meuibr propria gradually acquires a fibrous structure, and their cell growth becomes more cylindrical in form. The hepatic artery (Fig. 37, 5 ; Fig. 39, h\ which is distributed mainly to the walls of these ducts, anastom in the interlobular areolar tissue with branches which reach the surface of the liver from the neighbouring arteries of the diaphragm. Its veins open at once into the adjacent portal branches, to be distributed, through these, to the general capillary network of the parenchyma. The function of the liver is two-fold : the secretion of bile, on the one hand ; the elaboration of blood, on the other. By both these functions it is related to the diges- tive act : by the former, inasmuch as the admixture of bile in the intestine with the various other secretions, and with the food present here, gives rise to reactions which directly BILE. 191 influence the digestive solution; by the latter, inasmuch as the portal blood, which receives the greater part of those alimentary materials capable of absorption, passes to the liver, to undergo the action of this gland. The bile is a structureless, transparent, yellow liquid, with a bitter taste, a peculiar smell, a specific gravity of about 1020, and a somewhat viscid consistence. It not only resists putrefaction, but is antiseptic when added to other organic mixtures. When first secreted, it is neutral or somewhat alkaline. Any marked acidity is due to disease, or to decomposition subsequent to secretion. A scanty and casual admixture of cell-growth is often found in the hepatic bile. In the gall-bladder, the bile becomes some- what more concentrated or less watery ; deepens in colour to a greenish hue ; and is rendered more viscid by an ad- mixture of mucus, which is derived from the lining mem- brane of this reservoir. The quantity of bile secreted in the healthy human adult probably ranges from 3 to 5 lbs. daily : averaging at least 3^ or 4 lbs. Its secretion is continuous ; but is in- creased after a meal, and apparently rises to its "maximum as the act of digestion brings about the absorption of con- tinually increasing quantities of nutriment. Thus attain- ing a considerable quantity about two or three hours after a meal, the liquid of the bile gradually increases, and the proportion of its solids still more so, until, about ten to fifteen hours after the ingestion of food, both the bulk of secretion, and the weight of solid residue, attain their climax ; to sink progressively, by continued fasting, to reach a minimum during starvation. 192 DIGESTION. The exactness of the above statements is, however, rendered doubtful by certain complications : which are ascribable to the influence of the gall-bladder, and to the mechanism through which the digestive process is brought to bear on this reservoir, and on the various ducts. The small capacity of the gall-bladder in comparison with the daily amount of bile, concurs with the great increase of solids shown by its contents — in some cases from three to five times the solids of the hepatic bile, — to indicate an extremely active resorption of water, and concentration of bile, in its cavity. Whether, under any normal circum- stances, the hepatic bile is poured out into the bowel dur- ing digestion, while the cystic remains unclaimed, is at present doubtful. But it is probable that, in the ap- parently simple mechanism of the duodenal opening com- mon to the biliary and pancreatic ducts, distention of the bowel can scarcely do more than assist that closure of this orifice, which must be ascribed mainly to the muscular contractions of the duct and of the intestine itself: and that it is essentially the increased pressure of the copious secretions which throws open this valve for the transit of both the bile and the pancreatic juice. A reservoir of so variable a size as is the gall-bladder — which in many animals is absent ; and in many other-. > quite incapable of containing more than one-tenth to one- twentieth of the bile secreted daily — cannot have more than a collateral relation to the secretion of the bile, el- even to its discharge into the intestinal canal. Allowing for the concentration the gall-bladder effects in its con- tents, and further allowing for the influence of numerous COMPOSITION OF THE BILE. 193 meals in a day, as contrasted with a single large ingestion of food, we can scarcely avoid the conclusion, that bile is not diverted so exclusively into this cavity during fasting, but that a scanty proportion is constantly entering the bowel to undergo absorption there. The appearances of the fasting intestine, as well as the phenomena of vomit- ing (see Appendix A.), confirm this view ; by showing the constant presence of bile in the intestinal canal when digestion is not going on. Hence we are obliged to infer that, in animals which possess a gall-bladder, the flow of bile into the duodenum, remittent partly as a result of fluctuations in the process of secretion itself, is virtually rendered still more so by the condensed and accumulated state of the secretion which this reservoir collects during fasting, and empties into the bowel at a certain advanced stage of the digestive act ; but that both the secretion and re-absorption of bile are essentially uninterrupted. At the. outset of digestion, however, it seems likely that all entry of bile into the duodenum is for a time completely cut off. The composition of the bile is subject to such wide variations of quality and quantity, that nothing short of a careful collation of numerous observations promises any- thing like a safe estimate. While, as regards many of its details, no such materials are yet at our disposal. For example, the solid contents of the secretion have been found to range in different animals and specimens from 2 to 25 per cent. Assuming Frerichs's estimate of 14 per cent., we may regard the following as an approxima- tion to its constituents in the human subject : — o 194 DIGESTION. Water 860 Solids 140 f 105 taurocholates and glycocholates. Organic 122 < 16 fat, colouring matter, cholestearin. L 1*6 mucus. {5* chloride of sodium. 2*9 phosphate of soda. 1-4 phosphate of potash. •5 phosphate of lime. •28 phosphate of magnesia. Free carbonates, iron, silicic acid. 1000 The large deficiency of the inorganic ingredient is in part explained by the quantity of alkali (chiefly soda) which is combined with the resinous acids, fat, and colouring matter, of the organic ingredient. The taurocholate and glycocholate of the bile are regarded as double fatty (or rather resinous) acids ; formed by the combination of taurine (C 4 H 7 N S 2 6 ) and glycine (C 4 H. N 4 ) with . cholic acid (C 48 H 39 9 + HO) respectively. The former thus contains so large a quantity of sulphur as to amount in some instances to 6 per cent, of the total biliary secretion. The colouring matter, which contains about 6 or 7 per cent, of nitrogen, is probably derived from that of the blood : and is stated by Berzelius to have a composition identical with that of the chlorophyll of plants. The fats are partly dissolved by the aid of the taurocholic acid ; partly com- bined as fatty acids with the alkalis present. Very little bile appears to leave the intestines with the healthy fa?ces. A variable quantity of its pigment may. however, be thus traced out of the body. And it seems certain that portions of its resinous acids are gradually precipitated in their passage through the bowel in the form USES OF THE BILE. 195 of calcareous and insoluble salts; while others are de- posited as insoluble by increasing oxidation. Taurin may thus be detected. But it would appear, from observa- tions and analyses by Bidder and Schmidt, that the quan- tity of its solids thus disposed of is but a very small fraction (less then ^th?) of the original mass: the greater part of which thus undergoes re-absorption in its course along the intestinal canal. The ultimate destiny of the re- absorbed bile is unknown. But we may conjecture that its large ingredients of carbon, hydrogen, and even nitrogen, are ultimately dismissed from the system through the ordinary channels for the excretion of the compounds of these elements ; namely, the lungs, the skin, and the kidneys. How many times, prior to this exit, they repeat their cycle of movement through the bowel, remains utterly unknown. The influence of the bile on digestion has been best studied by the admirable researches in which Bidder and Schmidt have detailed the various results of its absence, as seen in animals in whom they diverted the duct and its contents completely away from the bowels, through fistulous apertures which led it out of the body. As the general result of these and similar researches, it may be stated that the bile, though highly recre- mentitious, is yet not essential, either to digestion or to Life. For if fche total loss of the bile be compensated by a largely increased ingestion of food, the animal thus robbed of this secretion may survive during an almost indefinite period. And the details of that extra want of food, which is thus entailed by the withdrawal of the bile, 196 DIGESTION. seem to consist, not merely in the loss of the hydrocarbons contained in the bile itself, but also in that diminished absorption of fat which the loss of this adjuvant secretion brings about. The faeces of such an animal, whitish and ineffably putrid as they are, do not show any quantity of undigested meat-fibre. But the fatty constituent of the food passes largely away in the stools. It would thus appear that the bile, by moistening the villi, in some way aids the penetration of these structures by the neutral fats — a fact which has indeed been rudely verified by expe- riments made on these two liquids with capillary tubes. And the increased voracity and need of the fistulous animal point at its organism being compensated, by an in- creased assimilation of albuminous substances, for the hydrocarbons thus lost to it from those alimentary, as well as biliary, sources of fat which are open in the unin- jured animal. From what ingredients of the portal blood the bile is furnished, can only be conjectured generally ; though the circumstances of its secretion point to its being derived more largely from the ingesta than from the system. Certainly the phenomena of this secretion, both in disease and starvation, conclusively indicate that it forms no ne- cessary or unavoidable stage in the waste or removal of adipose tissue from the system, much as its large fatty ingredients might favour such a supposition. In any case, some of its most important ingredients appear to be formed in the liver itself. The relation to digestion of the liver — as an organ stand- ing midway between the alimentary canal and the ge- CHANGES OF HEPATIC BLOOD. 197 neral circulation, in the transit of the various materials absorbed into the portal system from this tube — constitutes another aspect of its use in the oeconomy, and one which is even less known to us than its function as the organ which secretes the bile. Bernard has, indeed, found that the injection of peptone into the general circulation, is followed by the extrusion of albumen in the urine ; while if thrown into the portal vein, and thus allowed to traverse the liver, no such extrusion takes place. How far, however, such an assimilation of peptone should be assigned to the liver as an organ specially effecting it ; — how far to such a long delay, or slow progress, of the blood in the interior of a large gland as would alone permit this vital fluid to effect the elaboration or removal of peptone — remains for the present in doubt. But it is probable that a whole series of actions of an analogous kind belong to the liver itself, quite apart from the secretion of bile. Were our analyses perfect, the contrast between the constituents of the portal blood and those of the hepatic vein would give us, as it were, the exact complement of the bile. The former variety of blood , minus this secretion, would exactly correspond to the latter. And in this latter variety of blood, we might ex- pect to find at least some of the alimentary products ; which would scarcely yield up the whole of their substance to the bile they largely help to compose. Such a comparison has indeed been attempted*; and with results which, whatever their exact value, suggest some striking considerations. The hepatic blood, com- * Lehmann, op. cit. vol. ii. p. 80 et passim, o 3 198 DIGESTION. pared with the portal, contains less water, and more ex- tractive — in which latter term we may include its glycogenic or saccharine ingredient. Its fats are reduced to one half, and among these the copious elain of the portal blood is especially deficient. Its albumen is also reduced to one half, and its fibrin greatly diminished. In connection with these circumstances may be noticed the appearance of an unusual number of pale corpuscles; and what is probably an absolute, as well as relative, diminution in the numbers of the red globules. Finally, Schmidt has called attention to the fact, that the composition of the fat lost from the portal blood is such as would allow us to imagine its separation, with little change save a small increment of oxygen, into those two ingredients — cholic acid, and glycogen or grape sugar — which seem to form the main features of the hepatic function, both in respect of the secretion of bile on the one hand, and of the elabo- ration of the portal into hepatic blood on the other. The further progress of digestion in the small intestine continues the changes set up by the foregoing secretions. The absorption of fat, the absorption (and probably the formation) of peptone, the conversion of starch into sugar, and the absorption of sugar and of water, are prolonged throughout the whole length of this part of the bowel : at the end of which they enter the large intestine.* * Several figures in the foregoing chapter owe some details to Koelliker's admirable engravings. 199 CHAP. VI. DIGESTION. — THE LARGE INTESTINE. Large Intestine, its Measurements, Divisions. — Caecum ; its Shape, Structure, Openings. — Ileo-caecal Valve. — Vermiform Appendix. — Colon ; its Form, Structure. — Its Movements ; observed, deduced. — Kectum ; its Situation, Shape, Structure. — Its Sphincters. — Its Contractions; propulsive, expul- sive or Defecation. — Its Folds. — Mucous Membrane. — Arteries of the Intestinal Canal; Superior, Inferior Mesenteric, and their Branches. — Intestinal Veins. — Eationale of the Intestinal Vessels. — Nerves of the Intestinal Canal. — Lymphatics. — Contents of the Large Intestine: Faecal, Gaseous. — Digestion in this Segment. — Office of the Caecum. — Duration of Intestinal Digestion. — Faeces. — Their Properties ; Sources. — Mechanical Ingredients. — Chemical Composition. — Intestinal and gastric Oases. — Their "Composition, Nature, and Sources. — Their Kelation to Secretion. — Their Absorption. — Kelation of Digestion to Nutrition. — Intermediate Circulation. — Digestion, its Expenditure of Force. Large Intestine. — This part of the alimentary canal, beginning at the lower end of the ileum in the right iliac fossa, passes upwards to the under surface of the liver. Here, turning at a right angle, it runs horizontally below the stomach, to its left extremity. By a second bend, it now regains the vertical direction ; and passes downwards towards the left iliac fossa. In this region it next forms a curve like an S, thence named the sigmoid flexure ; from the lower end of which it passes down wards obliquely towards the median line, where it ends in a short tube, which runs in this line to the anus. In this course, its o 4 200 DIGESTION. average length is from four to six feet ; its width from two to three inches : two measurements usually varying in- versely as each other, except under extreme distention and contraction ; by which both may be respectively in- creased and decreased simultaneously. Such an estimate, Fig. 43. Large intestine, as seen in situ, in a state of moderate inflation. The ante- rior wall of the belli/, and the small intestine, are supposed to have been removed. c, caecum ; a. ascending portion of the colon ; t, transverse portion ; d, de- scending portion ; s, sigmoid flexure ; r, rectum. which assigns to the large intestine about one-fourth the length, and twice the width, of the small, suggests a toler- ably equal capacity for both. But the active surface of the large intestine is scarcely one-half that of the small : THE CECUM. 201 a difference further increased by the absence of those villi and valvulce conniventes (pp. 143, 151), by which the mucous membrane of the narrower tube is virtually so much increased in superficial extent. Consisting of the usual serous, muscular, and mucous coats, with their vessels, nerves, and lymphatics, the large intestine is divided by differences in the nature and ar- rangement of these tunics, as well as by other peculiarities relating to its size, shape, and situation, into the follow- ing segments: the ccecum; the vermiform appendix; the colon (in which are distinguished an ascending, transverse, and descending portions, and a sigmoid flexure); and finally the rectum. The ccecum (formerly called the " blind gut ") is so named from the fact that the cylindrical ileum, instead of being simply produced and dilated into the large intestine, opens into it at right angles at some distance from its commencement, leaving its blind extremity behind the site of their mutual junction. In diameter, this pouch usually exceeds the remainder of the bowel ; being only surpassed by the stomach. When moderately distended, it measures about three inches in length and width ; the former measure- ment having an arbitrary limit in the direction toward the anus, at the level of the ileo-caecal valve. Its situation allows it great fluctuations of size without any marked change of relations. Bound down to the fascia covering the muscles in the iliac fossa by peritoneum and areolar tissue, its enlargement merely displaces any portions of the small intestine casually in contact with it here, before bringing the anterior aspect of its own outer surface into 202 DIGESTION. contact with the anterior wall of the belly in the iliac region; where its size, shape, and even contents, are thence- forth often recognizable during life to a suitable physical examination. The somewhat globular shape of the csecum is qualified by the arrangement of its muscular coat, which here assumes a peculiar arrangement, maintained to the end of the colon. The external or longitudinal layer, instead of forming an uniform expanse, is separated into three flat- tened bands, which occupy the tube at nearly equal dis- tances from each other : one (the larger) anterior : one posterior ; and one external. All of these are continuous with similar bands which pass along the ascending colon. Between these slips of muscle, the bowel presents a dilated or projecting surface ; which is subdivided by transverse constrictions into subordinate pouches or sacculL When examined from within, these constrictions are seen to be formed by the circular muscular layer; which sends in- wards projections that complicate the general cavity of the tube, by surrounding it with a number of supplementary cavities or cells. These cells are arranged in three vertical rows : separated by ridges, which are the reverses of the vertical depressions formed externally by the longitudinal bands. Between these bands, the cells or pouches of the bowel are covered by a muscular wall of great tenuity : the transverse layer being reduced to a thin membranous ex- panse, and the longitudinal (as already stated) altogether absent. The peritoneum covering the caecum fixes it closely to the fascia covering the iliacus muscle. In a state of mode- THE CJECUM. 203 rate distention, the tube is only clothed by it anteriorly. But when much contracted, the intestine acquires a more complete covering : which is sometimes also produced into a kind of meso-caecum behind it. Conversely, distention of the tube restricts the caecum covering to the anterior third (or even less) of its circumference. Fig. 44. CcBcum inflated, dried, and opened, to exhibit the arrangement of its valve. a, termination of the ileum ; b, ascending colon ; c, caecum ; d, transverse constriction projecting into the caecum from its inner surface; ef, valve separating the small from the large intestine ; e, its horizontal ileo- colic lamina ; /, its more oblique ileo-caecal lamina ; g> the vermiform appendix of the caecum. The mucous membrane of the caecum has the same structure as that of the large intestine generally, up to 204 DIGESTION. the very edge of its junction with the ileum. Its aper- tures are three : one, that nominal aperture by which it is really continuous with the colon ; a second, which com- municates with the ileum, and is guarded by a double valve ; and a third, the orifice of its slender vermiform appendix. The opening into the ileum is situated at the junction of the upper, posterior, and left aspects of the caecum ; and the structures which bound it are often collectively termed the ileo-colic, or the ileo-caecal valve — names which in strictness belong to their two separate portions. Their ar- rangement may be described as follows. The end of the ileum, inclining upwards and backwards, meets the caecum at an acute angle. But instead of opening into one of the pouches or sacculi, it enters the caecum in the exact site of the deepest or most projecting of those transverse con- strictions which encroach on the general cavity of the bowel. This constriction, occupying the inner or left side of the caecum, is, as it were, split up by the entering ileum into two lamina, an upper or ileo-colic, and a lower or ileo-caecal (e, /, Fig. 44) ; at the same time that the hitherto cylindrical calibre of the ileum is gradually com- pressed into a horizontal slit or fissure as it traverses this fold. Each segment of the valve is formed chiefly by the prolongation of a corresponding portion of the circular muscular fibres of the ileum, interlaced with a few proper to the caecum. But the scantier longitudinal fibres derived from the ileum, as well as its peritoneal investment, are also attached to the fixed margin of each segment of the valve : the shape of which (as shown by the result of their division) they materially aid to preserve against ILEOCECAL VALVE. 205 any tractile force. Of the two segments, the ileo-caecal has a more oblique plane, and a more concave margin. The mechanism of the valve is easily deduced from its structure. In the absence of actual distention, the pas- sive contraction of its muscular walls ensures their contact. Any active dilatation of the large intestine — whether caecum or colon — at once ensures their still more forcible apposition : not so much by the mere pressure of the distending contents on the colic and caecal surfaces of its upper and lower portions, as by the conversion of the two curved borders of each portion into straight lines — chords of the previous arcs — which necessarily take the closest coaptation. The process is well seen by gradually dis- tending the caecum with liquid after death ; an experiment which proves that the closure of the valve is in a great degree independent of all active muscular contraction. Distention of the large intestine, and closure of the valve, are thus made the common and equal results of increasing repletion of the tube below it. The only ex- ception to this law is found in cases in which the caecum and ileum are filled simultaneously. Such a process necessarily occurs in all cases of mechanical obstruction of the large intestine near the valve ; the onward flow of the contents of the ileum first filling the adjacent caecum and colon, and then distending the aperture by that counter force which is applied on the further accumulation of con-^ tents in the small intestine. The effect of such a process is well seen in the ordinary inflated and dried prepara- tions of these parts (Fig. 44) ; in which preparations the aperture displayed must therefore be always regarded as strictly abnormal. 206 DIGESTION. The function of this valve may therefore be contrasted with that of the pylorus, in the fact, that while it is scarcely any obstacle to an onward transit of the canal behind, it resolutely bars all reflux ; an action which the pylorus might almost be regarded as reversing (p. 97). In like manner, we have found reason to conclude that, whatever the details of its active contraction, its efficiency mainly depends on a mechanism which is passive, physical, and permanent: while that of the pylorus is due to an active, vital, and intermittent process — to wit ; the con- traction of its own powerful muscular fibres. The use of the caecum is that of a receptacle, in which the matters passed onwards from the small intestine so- journ a while before entering the colon. Such a purpose is deducible, not only from its shape, size, and direction, but still more from its development in different animals. Thus the large caecum of the Hevbivora is contrasted with one of very small size and development in the Carnicora* In all these respects, however, it- does but correspond to the remainder of the large intestine, whose structure and function it shares. (Compare pp. 229 and 231.) The vermifomi appendix (g, Fig. 44, and below c c Fig. 15.), so named from its being appended to the caecum, and having a shape and size resembling those of a worm, is a small, smooth, cylindrical tube, which opens into the caecum below, and somewhat behind, the ileo-ca?cal valve. Its length is usually from two to four inches ; its width from three to four lines. Its attached end shares the situa- tion of the contiguous caecum. Its opposite extremity m usually free ; and hence may occupy any situation which VERMIFORM APPENDIX. 207 its short mesentery, and its own length, together allow it to take. Its opening into the caecum is generally narrowed by a transverse fold or valve of varying depth. Its struc- ture only differs from that of the caecum in the circum- stances of its having an uniform muscular wall ; and in the number (almost a continuous layer) of those follicles (p. 175) which are usually imbedded in its sub-mucous or areolar coat. The minute calibre of the tube contains glairy mucus, with w T hich are occasionally admixed fragments of th DIGESTION. hunger and want as to extract nourishment from sub- stances otherwise incapable of digestion, it is evident that these two constituents of the alimentary residue — undis- solved and insoluble, indigested and indigestible — may almost be said to merge into each other. The excretory element of the faeces consists chiefly of mucus and precipitated bile. This mucus, though for the most part structureless, includes variable quantities of scaly epithelium from the lower end of the rectum. In diarrhoea, numerous columnar cells from the intestine are often discernible ; as are also abortive cytoblasts, and simple ovoid cells. The latter, indeed, are sometimes sparingly present in healthy faeces; and are designated mucus-corpuscles. The biliary constituent is seen chiefly in the form of minute amorphous masses or molecules of a resinous character ; together with crystals or plates of cholestearine ; and soluble colouring matter, which often stains the above cell-growth, as well the other mechanical ingredients of the excrement. The crystals of ammoniaco-phosphate of magnesia often found in the faeces, both in health and disease, are derived from neither of the two foregoing sources exclusively. They are probably due to the action of ammonia (de- veloped in the feces before or after their expulsion) upon that neutral phosphate of magnesia which forms so large a proportion of the salts of the excrement. As respects any of its further details, the chemistry of the faeces varies so widely with the nature and amount of their several ingredients, that it is almost impossible to deduce any average. As a rule, however, the feces con- CHEMISTRY OF THE F.ECES. 237 tain about 25 per cent, of solids : of which the alcoholic extractive, the watery extractive, the insoluble residue, and the ash, maybe regarded as each forming about one-fourth. With a bulky bread diet, however, Berzelius found the insoluble ingredient three times as great as this estimate would suggest. But in the absence of information, respect- ing their exact sources — alimentary or intestinal — even the larger and more constant ingredients of such analyses suggest few practical conclusions. We can but conjecture that, while the protein-compounds of healthy excrement are derived almost exclusively from the food, some of its fat, and most of its muco-gelatinous extractive, have a secre- tory source. As regards the ash, it would seem that the soluble salts form about one-third, a proportion also reached by the alkaline and earthy phosphates. The chlorides are in a very small proportion (about -fo^ 1 )* equalled (often far exceeded) by the sulphates. Potash greatly (ten to forty times) exceeds soda ; magnesia reaches the relatively large amount of half the lime. The alkaline carbonates found in human excrement are probably referrible to the decomposition of some organic salts of these bases. And others of the foregoing peculiarities, as well as some not alluded to here, are probably referrible to the following circumstances : — the large addition of certain ingredients in the food, as of potash ; the large removal of certain salts by other channels, as the chlorides by the urine; and the scanty absorption of certain minerals, as of the magnesian salts, by the bowel. The gases always contained in the large intestine, and often expelled from it, may be conveniently noticed in con- 238 DIGESTION. nection with the similar gases which are found in the stomach and small intestine. The analyses of Jurine, Magendie, Marchand, and Chevreul, maybe summed up as follows: — Whence obtained. Com posit ion by V olume. o. s. C0 2 . H. CH 2 SH 2 . Stomach. . 11 71 14 4 Small Intestine — 32 30 38 Caecum — 66 12 8 13 ] Colon — 35 57 6 8 > trace. Rectum . — 46 43 — 11 1 Expelled per anum — 22 41 19 19 i To such a summary of their composition we may ap- pend the following observations on their probable nature and sources. 1. Air is habitually introduced into the alimentary tube from without the body : by some persons voluntarily, as an act of deglutition or eructation ; by all persons in the ordinary act of swallowing, in a state of mechanical adhesion to the bolus of food, as well as of minute division in the frothy saliva. The air thus introduced into the stomach undergoes a process of diffusion or interchange with the elastic fluids dissolved in the blood of the gastric capillaries ; a diffusion which converts it into a mixture containing less oxygen, but more carbonic acid, and in a degree varying with the duration of its sojourn in the stomach. But the gases of the stomach are evidently derived chiefly from some other source. For the quantity thus GASES IN THE ALIMENTARY CANAL. 239 introduced is small: while the stomach and intestines may be generally shown by percussion to be largely oc- cupied by gases. And not only is the increase of carbonic acid disproportionate to the decrease of oxygen, but a new element, hydrogen, is added. The same arguments apply even more strongly to the aeriform contents of the intestines. 2. Gases are developed in the alimentary canal by the decomposition of the food it contains. There can be little doubt that such fluids are chiefly due to this process. The metamorphoses which elaborate the food into matters fit for absorption, are so easily capable of being pushed a step further, and of giving off gaseous fluids, that, though it is one of the offices of the various digestive juices to repress and prevent all decomposition or putrefaction in the strict sense of these words, still some fraction of the food ge- nerally escapes their complete influence, and under the heat and moisture present in the canal, is converted into gaseous fluids, similar to those producible by de- composition without the body. Indeed, it is obvious that nothing short of the most exact adjustment of the various secretions, both in quantity and quality, to the several alimentary constituents of the food, could be expected altogether to obviate such an evolution of gaseous fluids. Such a process exactly accounts for both the nature and proportions of those constituent gases noticed in the above table : as well as for the ammonia which is probably precipitated from them in the triple salt of magnesia formed within the intestines. And not only is this view confirmed by the known composition and reactions of the food, but the conditions known to favour or oppose flatulence 240 DIGESTION. remarkably substantiate its accuracy. Too large a quantity of food, too defective a quantity or quality of digestive secretions, notoriously increase these gases to the degree termed " flatulence." And many kinds of food are equally influential ; sometimes by the fermentation they set up (as in cattle surfeited by moist green food), sometimes by the composition (sulphur forming sulphuretted hydrogen, as in animals largely fed on beans) they possess. Further, while the remarkable variations in different analyses sug- gest some cause not less variable than the food, and are very unlike the comparatively constant composition of animal products and tissues, it is well known that the absence of all flatus, and the contraction of the intestine into a narrow thick white tube, constitutes one of the evidences of death by starvation. 3. Another source of flatulence suggests itself in the case of various constitutional diseases : namely, the evolu- tion of gases by the decomposition or putrefaction of fluids derived from the organism itself. That gases may be thus evolved in cavities of the body seems established by various authentic cases of physometra ; where the elastic fluids which distended the uterus could only be referred to such a source. And, from analog}', it seems probable that, in various disorders known to be attended with a peculiar proneness of the fluids to putrefaction, the spontaneous decomposition of the inc/esta contained in the digestive tube, favoured by heat and moisture, and unchecked by the action of healthy digestive juices, is accompanied and furthered by a kindred decomposition in these depraved and altered secretions themselves. GASES IN THE ALIMENTARY CANAL. 241 4. It has often been supposed that gases are set free in the intestinal canal, by a process of secretion or transpira- tion from the blood. But a careful inquiry justifies the denial of such an occurrence. For, to say nothing of the complete inapplicability of the term * secretion " to a pro- cess which, if it occurred, would, from all analogy, con- stitute an act of diffusion of the same kind as that which obtains in the lungs and skin, — all the facts hitherto ascertained concur to disprove even this qualified evolution of these gases from the blood. As already noticed, the gases found in the intestines are, both in quantity and quality, precisely those which would be evolved by the decomposition of the various substances used as food ; and under circumstances of complete and sudden starvation, are often entirely absent from a great part of the alimen- tary canal. Some of them — such as hydrogen, carburetted hydrogen, and sulphuretted hydrogen — have never been detected in the blood in that appreciable quantity, which would be necessary to explain their evolution from it. Nor can any parallel to such a gaseous excretion be found even in the case of those structures which, like the lungs, are specially organised with reference to the giving out, from the blood, of certain of its gases, and the taking in of others from the surrounding air. For the gases just alluded to, as absent from the blood, are equally deficient in the air of exspiration ; nay more, involve, directly or in- directly, a deoxidation of water, such as is not only without parallel in the chemistry of the organism, but is curiously opposed by that oxidation of hydrogen which forms about a pound of water daily (p. 10) in the healthy human subject. B ll 242 DIGESTION. While the carbonic acid and nitrogen common to flatus and to exspiratory air are scarcely less distinguished by their quantitative relations, than are the other intestinal gases by their presence and absence respectively. In round num- bers, we may estimate that flatus contains ten times the proportion of carbonic acid, and two hundred times the proportion of nitrogen, in the air exhaled from the blood by exspiration. And although, in favour of the secretion of gases by the digestive tube, many authorities quote the well-known experiment by Magendie, in which the deliga- tion of the empty intestine of a healthy dog was soon fol- lowed by its distention with flatus ; yet the inconclusiveness of this argument will sufficiently appear, when it is pointed out, that the experiment does not exclude all alimentary matter. 'On the contrary, since one grain of starch or sugar would yield, by decomposition, gases capable of occupying about eight cubic inches of space, no such ex- periment can exclude the presence of sufficient food to account for the gases of the resulting distention : — can approach, indeed, the trustworthiness of the contrary observation, as to the empty and contracted state which often results from starvation. The gases expelled from the rectum carry with them the characteristic odours of the excrement : with which it is probable they are mechanically impregnated, as a result of mere contact and diffusion in the bowels. But it is also probable, that the introduction of certain foetid substances into the blood is followed by their specific determination to the mucous membrane of the intestinal tube, as the destined channel of their elimination from the svstem. CIRCULATION OF DIGESTIVE SECRETIONS. 243 For it is well known that, after the inhalation of any offensive odour, both faeces and flatus often exhibit what is unmistakeably the same odour, in a comparatively con- centrated form. And the active diarrhoea which frequently attends this reproduction of the original odour, seems but an increased effort of Nature, to remove what both the special sensibility of the olfactory organ, and the organic irritability of the intestinal canal, alike testify to be noxious to the system at large. How far the expulsion of these gaseous fluids is deter- mined by their quality, as well as quantity, remains un- decided. We are equally ignorant how far, failing all such expulsion, these gases may be absorbed into the blood ; and if so, where, and in what form, they emerge from the vascular system. The smallness of that quantity of sul- phuretted hydrogen which is really present in the most offensive flatus, and the comparative harmlessness of its carburetted hydrogen in those proportions in which alone it could be dissolved by the blood, prohibit any deductions based on the ordinary physiological action of these two gases. We can but conjecture that whatever absorption they may undergo is slow enough to allow all accumulation to be prevented by such an oxidation — whether in the lungs or elsewhere — as would necessarily destroy all their poisonous qualities. Lastly, the subject of Digestion would be very incom- pletely noticed without some allusion to another relation borne by this function to Nutrition in general. The admir- able researches of Bidder and Schmidt conclusively show, R 2 244 DIGESTION. that the various secretions which effect the elaboration of the food are habitually poured out in very large quantities. Of these quantities, again, so small a proportion leaves the alimentary canal with the fseces, that the bulk of every such secretion may be regarded as poured into one part of the tube, to leave it, by resorption into its blood-vessels, in another and lower segment. What between bile, saliva, and the gastric, pancreatic, and intestinal juices, from twenty to twenty-five pounds of liquid, with solid contents which average about three per cent., are daily undergoing a slow continuous cycle of movement, as a kind of intestinal offshoot of the general current of the blood. The changes or elaborations of these secretions themselves remain in great part unknown. But even presuming them to be far less important than all analogy would indicate, their in- fluence in merely furthering the general changes of Nu- trition must be very considerable : aiding, as they would necessarily do, that general exchange of substance which applies the ingredients already rendered effete and ua by one part of the body, to the nutrition and function of another. Or — to adopt the readiest illustration — ji> a liberal supply of water, the universal solvent and carrier of the nutritive process, defers and protracts (p. 66) the process of starvation, so the stimulation of the digestive organs by the ingestion of food may aid Nutrition, quite apart from the nourishment it more slowly prepares fc - similation to the system. Proofs of this action are. indeed, familiar incidents of the records of hunger and starvation : in which substances themselves (quantitatively or qualita- tively) little or not at all nutritious, have often been found LABOUR OF DIGESTION. 245 to produce invigorating effects, which, however fleeting, have been far too rapid and energetic to be otherwise ex- plained.* One final reflection must also be added : namely, that the magnitude and exactness of the whole digestive pro- cess well suggest the wear and tear it implies to the system at large ; and the fatigue — if we may use this word in so metaphorical a sense — to the organism in general, which the excessive ingestion of food, whether relative or abso- lute, must necessarily amount to. The practising physician sometimes sees patients whose constitutions are thus worn out by the mere exertion of good living, uncomplicated by any other variety of mental or bodily toil. And even in those states of debility which demand careful support, it is often a matter of great nicety for him to decide when that generous diet which is called for by the symptoms would, if pushed any further, begin to oppress and detract from the strength it is intended only to support. * Among instances of this kind one of the most characteristic is recorded in 1 Samuel, c. xiv. yv. 27 — 29. R 3 246 CHAP. VII. VARIETIES OF FOOD. — ANIMAL FOOD. Ingredients of Food. — Animal and Vegetable. — Their Mixture natural for Man. — Their Variation contingent. — Nutritional Influence of Foods. — Contrast of Animal and Vegetable Food. — Varieties of Animal Food. — Meat or Flesh. — Its Chemical Components. — 1. Fibrin. — 2. Albumen. — 3. Gelatin. — Its Sources. — Nutritional Value of it, and of the Collagenic Tissues. — 4. Fat. — Its Sources. — Its Kinds. — Its Nutritive Value, in Animal, Vegetable Food. — Its Digestibility, as affected by its Kind, by Climate. — Its Destiny, when assimilated in Excess. — 5. Inorganic Con- stituents, contrasted with those of Blood. — 6. Secondary Organic Com- pounds. — Other Kinds of Animal Food. — Organic Muscle. — Heart. — Tongue. — Respiratory. Tendinitis, Muscles. — Influence of I Sex, Habits of Animal. — Flesh of Birds. — Fish. — Blood. — Brai: H Glands. — Bone. — Eggs. — Milk. — Variations in different Animals as to Quality, Quantity. — Influence of Date of Lactation. — Physical Arrange- ment of Milk. — Cream. — Butter. — Its Components. — Its Nutritive Value. — Cheese. — Its Composition. — Its Varieties, — I*- Nutritive Value. The preceding chapters, which have successively noticed the various alimentary constituents found in a typical food — milk — and the several structures and functions con- cerned in the process of Digestion, will together afford us a clue to the composition of the principal varieties of food. For, however widely these varieties may appear to differ from each other, they will always be found to contain representatives of each of these alimentarv constituents. And the best food for any particular animal will necessarily consist of such proportions of all of these, as will most ANIMAL AND VEGETABLE FOOD. 247 exactly correspond to the demands made by the waste of its whole body, on the one hand, and to the peculiarities of its digestive organs, on the other. Organic, as already stated, in its nature, the most obvious subdivision of food refers it to the two great forms of Life, animal and vegetable. A mixture of these two kinds of organic substance must unquestionably be regarded as the natural food of man. Whether we look to the Biblical announcement of his destiny in this respect, or to the more specific line of con- duct prescribed to a particular nation, in what must be acknowledged as the admirable sanitary code of the Hebrew Theocracy ; to the present and past habits of the human race in general ; or to those instincts which, in the main, these habits express and represent; we meet with facts which alike establish this proposition, and com- pletely shelve the question of the so-called vegetarian — "Is animal food permissible or advisable?" But while it is beneath the dignity of science directly to moot this last inquiry, the information she seeks, as to the natural proportions in which the two kinds of food ought to be mixed, indirectly decides it. We look to the teeth ; and find them representatives of the cutting, tearing, and grinding organs of the Carnivorous, Herbivorous, and Grranivorous animals respectively. We unravel the coils of the tortuous bowels ; and find them also, in respect to their length, their surface, and their distinction into small and large intestine, intermediate between the Carnivorous and Herbivorous intestinal canal. Nay, more, without adopting the numerical argument of the author who con* B 4 248 VAKIETIES OF FOOD. siders the numbers of the various kinds of teeth as dicta- ting the predominant proportion of vegetable food ; or applying a similar numerical test to the human bowel, to infer a similar conclusion ; we may so far imitate the ancient augurs as to find, in Man's entrails, a clue to various dietetic, and even social, details of his Xutrition. With only one set of permanent molars, it is clear that he must either be as frugivorous as in Paradise, or resort to some kind of cookery which may economise these grinding instruments. With no paunch attached to his stomach, and but a moderate capacity of colon, he ought never to be far from his external stores of food, and should probably eat two or three times a day. Vegetables, and in large quantity, he is clearly intended to consume : the more so that, in respect to various details of structure and function, his large intestinal surface is gifted with energies far beyond what its mere comparative size would imply. Lastly, if we may accept the above description of a typical food, it is clear that this can scarcely ever be constructed, save by an admixture of animal* with vegetable food: the latter only approaching the requisite composition in the case of a few articles, themselves rarely grown in sufficient quan- tity and permanence save by the aid of animal products which, in practice, nothiug but the habit of slaughtering domestic animals could systematically supply. * Of course milk is to be regarded as animal food. For. not to speak of its indirectly requiring the sacrifice of life, we must keep to the actual met of its source, and ignore any such perversion of terms as would, if carried out strictly, cut a steak (like the Abvssinians do) from a living animal rather than from a dead one ; and call the former a vegetable food. MAN OMNIVOROUS. 249 But though we may somewhat vaguely assert a mix- ture of animal and vegetable diet to be our natural food, and may hence regard Man as an Omnivorous (Amphi- vorous?) animal, he merits the latter title in a much higher sense. For not only can he readily adopt an ex- clusively animal or vegetable food, according to the cir- cumstances in which he is placed, but he excels all other animals in this respect, just as much as he does in that diffusion of his species over the whole globe, of which this peculiar range of digestive power is at once the general cause, and the special condition. It is true that there are but few of the Carnivora and Herbivora, most strictly so called, in whom careful experi- ments would not detect the germs of a capacity for simi- lar changes of food : that the Horse and Cow have been brought to eat flesh and fish ; and that even some of the carnivorous Birds have been gradually accustomed to the far more difficult change implied in their feeding on grain. But, to say nothing of the psychical differences which their unaltered instincts really imply, none of these artificial (or rather compulsory) changes at all approach in rapidity and ease those which a healthy individual of the human species can accomplish, and which circumstances often necessitate or recommend to whole tribes and nations. Besides, in many animals, the capacity for such changes seems almost absent. Some of the frugivorous Quadru- mana seem little susceptible of these alterations of diet. And there seem to be numerous Insects, which are not only strictly limited to a vegetable food, but even to 250 VARIETIES OF FOOD. certain species of plants, or to particular parts of their structure. The influence of any special kind of food on the organism depends, not only upon its chemical, but also its physical properties ; in other words, not merely on its various constituents, as capable of being shown by chemi- cal analysis, but also on their mechanical arrangement and admixture. And it must be borne in mind that the original properties of food in both these respects are capable of being greatly modified by the operations of cookery (Chap. XII.). Contrasting the general characters of animal and vege- table food in these two respects, we must, on the whole, assign to the former the highest rank in the scale of dietetic value. For the tissues of one animal necessarily contain most, if not all, of those organic and inorganic substances which are required for the maintenance or construction of another; and that, too, in something like the fitting proportion of their respective ingredients. As a rule *, they are also devoid of downright poisonous constituents. Besides these, they offer the equally important advan- tages of possessing such a structure, arrangement, and solubility, as materially aid their entry into the organism. Hence they are not only much more nutritious than an equal quantity of vegetable food, and cover more com- pletely all the details of the bodily waste, but they are also digested and assimilated with far greater ease and rapidity. It is for these reasons that the use of animal food is so much to be preferred in circumstances in which * Some exceptions to this rule will be alluded to hereafter. COXTEAST OF AXIMAL AND VEGETABLE FOOD. 251 it is desirable speedily to avert any threatened exhaustion of the bodily powers. Against these advantages possessed by animal food we must, however, set off certain disadvantages. It contains some substances which, like the gelatinous and horny epithelial tissues, seem to be of comparatively little value for the purposes of ordinary nutrition. It doubtless in- cludes others which are so far noxious as to require speedy excretion ; as is the case with urea, and with those secondary organic compounds out of which this deleterious principle is immediately constructed. Besides, it is generally to be regarded as deficient in those non-azotised elements which are indirectly so important to the maintenance of the due combustion and heat of the body. For the mere quantity of fatty matter which it includes rarely suffices to make these hydrocarbons a proper substitute for the large starchy and sugary constituents of vegetable food ; and its quality still further reduces (under all ordinary circum- stances) the efficiency of this substitution. Hence for civi- lised Man, in temperate climates, we may safely assert that no excess of proteinous or of adipose tissues in the food can fully compensate the absence of the various hydrates of carbon. And while the main advantage of vegetable food lies in this large ingredient of hydrates of carbon, its disad- vantages are equally obvious. It generally contains but a small proportion of the protein-compounds. Even this limited quantity, again, is often virtually diminished by their insoluble state ; or by the indigestible form which is implied by their mechanical arrangement in the vege- 252 ANIMAL FOOD. table tissues. Many of its starchy constituents are also rendered useless in the same way : being enclosed in hard or tough insoluble envelopes, which effectually shield them from the digestive process ; or having a composition which requires to be altered by a chemical process of metamor- phosis before they can be fitted for absorption. It is true that some of these disadvantages may be, in great extent, obviated by the ingestion of a larger quantity of such food, as well as by a more protracted sojourn in the alimen- tary canal. But there is often a still more serious defect in its inorganic constituents ; which, in various kinds of vegetable food, appear quite insufficient to replace the salts lost by the waste of the organism. Thus the ash of some esculent vegetables is peculiarly deficient in phos- phates ; that of others, in the equally important ingre- dients of soda and chlorides. Lastly, the poisons contained in many plants constitute another objection to vegetable diet: an objection which is, however, generally obviated by the instinct of animals, the experience of Man. or the purification which the process of cooking often affords. Varieties of animal foocL — The muscular substance, together with more or less of its interstitial and investing adipose and areolar tissue, constitutes what is called flesh or meat in the ordinaiy acceptation of these words.* * The changes of meaning gradually undergone by various words in our vocabulary of diet, are curious and significant. Food, in old and accurate English, includes (and ought still to include) all kinds of nourishment : and is therefore misapplied when made the antithesis of drink. Meat, again, formerly included all aliments chiefly solid ; and was thus contrasted with drink, in an antithesis which its derivation (matyan, Anglo-Saxon, to eat) and relations (the maw or stomach, and the mouth) justified and confirmed. ANATOMICAL CONSTITUENTS OF MEAT. 253 The mechanical subdivision or dissection of an ordinary " joint of meat " might of course be made to reveal most of the numerous structures which unite to form its mass. ] Fragments of bone, cartilage, fibro-cartilage, or ligament, would probably be recognised as foreign bodies. Apart from these, however, the naked eye might distinguish more I or less of the fatty subcutaneous panniculus upon the I muscular layer ; the fibrous expanses or fascice that bind down the muscles and isolate them from each other ; and a quantity of adipose and areolar tissue lying beneath these fasciae, and further passing in between those larger and smaller bundles into which the primitive fibres are united to construct any muscle. Adding to these textures the nerves, arteries, capillaries, and veins, distributed to the con- tractile masses ; with the variable and often large quantity of blood these vessels enclose; and the almost unknown fluids which soak the whole mass, with qualities dictated both by the blood and by the particular tissue they occupy ; and also considering the various and complex tissues revealed by the microscope in these organs ; as well as the sarco- lemma, nuclei, and sarcode of the primitive fibrils them- selves : — it becomes evident that a piece of flesh is in reality the mechanical aggregate of a vast number of structures, This wider import is retained by the (cognate?) French word mets. What we now call meat, again, formerly required to be distinguished as flesh ; a distinctive term which, sometimes added to the preceding (flesh- raeat), seems to have been in common use at least as late as the time of De Foe. The derivation of the word is obscure : but it was clearly used '■ to denote the solid muscular tissues (as in the common antithesis, "flesh and blood") of the body: and the distinction offish, flesh, and fowl, was a i loose and inexact one, no way modifying its accurate meaning. 254 ANIMAL FOOD. which are capable of being mixed with each other in almost infinite variety in any succession of specimens. The chemical composition of meat must therefore vary with a host of circumstances. Not merely the species of animal, for example, which has yielded it ; or the part of its body from whence it is taken ; but its age ; sex : food : habits ; and doubtless even its individual peculiarities ; — all modify the constituents and the qualities of the meat. And while some of these modifications can be traced in its chemical analysis, and others are equally visible as quan- titative details established by the mechanical subdivision of its above constituents, many more are only made out, either by the delicate inquiries of smell and taste, or by equally delicate nutritional results. The average composition of the lean of beef may be stated at 77 per cent, of water, and 23 per cent, of solids. Of the latter, the following are the chief ingredients. 1. Syntonin, or muscular JUyrm 3 is a variety of this prin- ciple distinguishable from ordinary healthy blood-fibrin by some peculiarities ; among which a larger watery con- stituent, a diminished solubility in solutions of saltpetre and of carbonate of potash, and greater solubility by dilute hydrochloric acid, are perhaps the most marked. It forms about 16*5 per cent, of the whole mass, and is derived chiefly from the contents of the sarcolemma ; increased, in all probability, by a small admixture of ordinary fibrin from the blood-vessels of the muscular mass. Its compo- sition seems to be identical in the sarcode of both the striped and unstriped varieties of muscle. 2. Albumen, forming about 2*5 per cent., must doubt- GELATIN. 255 less be referred even more decidedly to the same double source, though it also comes chiefly from the sarcode itself. 3. Gelatin, derived mainly from the areolar tissue which lies between the primitive fibres, in quantities which indicate the substance yielding it to be present in the muscular mass in a proportion of about 2 per cent., has long been the object of a controversy, which has even yet scarcely decided its chemical position, much less its nutri- tive value ; and which, despite its inherent importance, as well as its value as an illustration of the difficulties of the physiology of food, can be but briefly alluded to here. Produced in large quantities by boiling various tissues of the body (skin, bone, tendon, and the like) known to pos- sess little nutritious value, gelatin or jelly had nevertheless long enjoyed a certain empirical repute ; both as an aid to other alimentary compounds, and especially as an ex- cellent adjuvant and preservative* of the more valuable liquids and solids derived from meat. Hence, when Papin obtained it in much larger quantities by the long boiling of bones under a high pressure in his " digester," the ex- aggerated views entertained of its value were too easily accepted. These views were indeed carried still further by subsequent French inquirers ; who were inclined to assert for gelatin a rank so pre-eminent in the scale of food, as to consider a gelatin lozenge a substitute for all * For example, the dish called an aspicTc (which name, by the bye, pre- sumably alludes, less to its having the venom of the asp, than to (cespen) its tremulous expectancy of being eaten) is a good illustration of the use of gelatin in preserving the delicate odour and flavour of the solids it enve- lopes, as well as of the albuminous and extractive matters which permeate its own mass. 256 ANIMAL FOOD. other aliment, and (for such phrases were seriously used) every knife-handle or toothpick made of bone or ivory as so much valuable material robbed from the general stock of human food. A gelatinous solution, mixed or unmixed with soup, had even been adopted at some Parisian Hos- pitals, as a large constituent of their dietary. At this time, a committee of the French Academy in- quired into its virtues; with the result of finding it not only insufficient as a food, but useless as an aid to other alimentary substances. And, confirmed as their state- ments were by a subsequent commission of the Institut at Amsterdam, the proposition — that gelatin is devoid of all nourishing qualities whatever — perhaps remains dominant to this da}^. And yet, on general grounds, the homely adage which dissuades children from S€ teaching their grandmothers to suck eggs," is perhaps fairly applicable to the iufancy of science, instructing the venerable experience of thousai of years on what is too often the great task of human life, the maintenance of bodily nutrition. While, to pass from generalities to details, the usefulness of gelatin, which seems thus deducible from instinct and experience, is con- firmed by a careful consideration of all the facts hitherto established. Modern chemistry finds that long boiling in water pro- duces, from three kinds of connective tissue, at least three varieties of gelatinous substance : one largely yielded by the tissues already mentioned in the form of ordinary jelly or glue ; another, the chondrine far more slowly formed by the similar treatment of cartilage ; and a third, perhaps even a fourth, from the yellow or elastic tissue of the PHYSIOLOGY OF GELATIN. 257 Mammal, and from the skeleton of the cartilaginous Fishes respectively. And we have seen (pp. 16, 50) that the com- position of gelatin is contrasted with that of protein chiefly in its smaller proportions of carbon and hydrogen ; while, as regards its origin, it can scarcely have any other source throughout the whole Herbivorous division of animals than a metamorphosis (probably regressive) of their albuminous tissues.* The physical and chemical properties of gelatin seem in- timately related to each other in the circumstance that both point to a high degree of cohesion, causing this substance readily to assume the solid form. And the tissues yield- ing it are chiefly distinguished by their mechanical offices ; which are mediated, we might almost say, by degrees and kinds of cohesive force, well represented by the tenacity of tendon, and the very diverse elasticities of bone, cartilage, and yellow fibrous tissue. Their scanty vascular supply, and their dilute nutritional fluid, sufficiently in- dicate the relative slowness of their nutrition. On the other hand, however, with tissues like these, no arrangements can obviate a large waste by friction. And the extreme solidity and cohesion of the material of these collagenic tissues, though only in consonance with the wonderful skill of its arrangement, leave (as in the arti- cular cartilages) valid evidence of an unavoidable and con- * The comparison, both of equivalents, and of percentages, would be equally compatible with the view of an accumulation or excess of nitrogen and oxygen, in gelatin, as contrasted with protein. But such a construc- tive or progressive metamorphosis of the latter substance, though not im- possible, is far less probable than the converse action assumed above. S 258 .ANIMAL FOOD. stant wear and tear, which is produced by their continual attrition. Some preliminary objections might well be taken against the inferences drawn from those experiments on animals above alluded to. For in all, gelatin is at first eaten eagerly, and for a time defers starvation. AVhile in some, the nutritiveness of gelatin is even more decidedly sug- gested, by positive experiences, which, as such, claim a greater value than their contradictory and negative results. But in all, the absence of complete analyses, and still more the presence of some degree of inanition, invalidate their conclusions ; at any rate, remit these to be established by experiments in which it is expressly sought to replace part (and that exclusively the proteinous part) of a food, found by observation to be sufficient for health, by the substitution of gelatin. Certainly the results of these Commissions render it probable that a portion of the albumen of a mixed diet might thus be substituted. Xor is it irrelevant to point out that, by parity of reasoning, both the white and the yolk of egg might be proved in- nutritious, in defiance of the experience that (whatever may be the case with Dogs) they are highly nourishing for Men, and are destined to be, for a time, the sole food of the embryo Bird which they enclose. The discovery of digested gelatin in the urine, after its injection into the veins, has been alleged as a proof of its innutritious character. But the fact may be contradicted, on the one hand. And the deduction may be demurred to, on the other. For Frerichs failed to find any such elimination. And Bernard has since extended a similar NUTRITIVE VALUE OF GELATIN. 2£9 statement to peptone, as being also eliminated by the kidneys when injected into the systemic vessels. Again, the statement of Frerichs, that the ingestion of much gelatin raises the proportion of urea in the urine, is one which, true as it undoubtedly is, no way militates against the nutritive properties of this substance ; save by arguments which, carried to their legitimate conclusions, would allege the same proposition respecting albumen, the large ingestion of which is followed by a like result. There is nothing to render it impossible that part of the gelatin thus ingested is assimilated, and that the surplus only is decomposed in the blood or the nutritional fluid, to be afterwards eliminated in this form. Boussingault* does, indeed, distinctly find such a partial disappearance of the gelatin of ingestion from the excretions, as can only be accounted for by supposing it really applied to the enrich- ing of the fluids, if not to the construction of the solids, of the organism. But it must further be pointed out, that even to assume the accuracy of such statements as the foregoing respecting the inefficacy of gelatin, would scarcely suffice to establish the validity of all those objections to the usefulness of the so-called gelatinous tissues which have been raised upon them. Eemembering what gelatin really is — an educt rather than a product ; certainly a very imperfect and dilute solution of some of the tissues which yield it ; a weak bulky hydrate of some constituent or constituents of the collagenic structures — we cannot fairly rest the * Comptes Rendus, Sept. 1846. s 2 260 ANIMAL FOOD, nutritive value of these on the nutritive efficacy of such a feeble and inefficient representative. These structures themselves, for example, dissolve rapidly and completely, under the influence of the gastric juice, into liquids quite undistinguishable from true pep- tone. Cubes of solid massy tendon, or even of no less massy yellow ligament *, thus dissolve in large proportions in a natural or artificial gastric juice. And parings of articular cartilage experience an even more rapid solution. All are thus converted into limpid transparent solutions, which are devoid of the reactions of either gelatin or chondrin respectively. It is equally certain that, besides undergoing the gastric metamorphosis, and assuming the form (peptone) of its product, these tissues share the alimentary virtues of the protein-compounds. Tendon, ligament, bone, cartilage, white and yellow fibre, nourish Dogs and some other C - nivora for great lengths of time, with little decrease of their weight, or detriment to their health ; although the albuminous constituent of these tissues is far too small to suppose it the only azotised principle assimilated. We must therefore remember that, great as may be the difference, for all nutritive purposes, between gelatin or its congeners, and the tissues which yield them, there is no reason for supposing these artificial extracts absolutely inert or valueless. That their value is so far proportional * In the experiments on artificial digestion above alluded to. I hare found that the chondrogenic mass (^as in the elastic ligamentum nucha of the Ox) dissolves more slowly, and in smaller quantity, than the eollagenie tissues ; which are easily taken up in three or four hours, at a heat of 103° F., and in four times their weight of artificial gastric juice. USES OF GKELATlff IN FOOD. 261 to their solidity, as that the jelly they deposit on cooling is the most valuable nutritive element of a meat-broth, we may utterly deny. But we are quite entitled to assert that they are nourishing in that twofold sense already as- signed to this term : — capable of undergoing a true assi- milation, on the one hand ; as well as a combustion which developes heat, on the other. While, as regards the tissues yielding them, it is exceedingly difficult to distinguish them from even the richest and best meats, save in the differences (relative to degree and not to kind) of their being digested with more slowness and difficulty, and as- similated at a corresponding disadvantage. That, in under- going assimilation, gelatin should tell first and most upon the tissues most akin to its own composition — namely., upon the various collagenic structures which Haller long ago estimated to form one half of the whole body — would be only in consonance with all we know of Nutrition generally. Certainly it is difficult to appreciate the argument, that because some animals eat none of these " gelatinous" tissues, therefore all others, who eat them enormously, do so in vain. But besides these, its alimentary properties, gelatin has other uses in reference to the preparation and diges- tion of food. The mechanical advantages of its con- sistence (especially in the form of collagenic tissue) in stimulating the organs of digestion, must not be over- looked. Its value as an agent in the preparation of food is even more important. Not only does its admixture confer on other alimentary ingredients an increase of surface, such as renders them more digestible ; but we ma}' claim for it a capacity for dissolving various of the ingre- s 3 262 ANIMAL FOOD. dients of flesh, as well as for inaugurating a process more definitely akin to their digestive metamorphosis by the gastric juice. In this manner, it can hardly be doubted that the formation of gelatin plays an important part in many processes of cookery; aiding the solution of al- bumen and its congeners, as well as enriching the mass by the addition of its own dissolved ingredients. 4. The fat of ordinary meat is a still more important ad- juvant to the muscular fibre in a dietetic point of view. In the flesh of animals artificially fattened, the fat often attains a proportion only limited by the degree in which the muscular bundles are artificially cleaned of their investing and interstitial areolar tissue, which is laden with an enormous mass of this kind. And even after all fat visible to the naked eye has thus been removed, large quantities are still to be detected by analysis. Thus Von Bibra has found fractions ranging from one-twentieth in wild animals like the Hare and Deer, to one-fifth in Ox- beef. And, to judge by the microscope, the analysis of the flesh of cattle fattened by stall-feeding would often show even this large proportion to be greatly exceeded. The sources of this varying proportion of fat must be sought, not only in those minute fragments of adipose tissue which the most careful dissection leaves attached to the areolar septa of the muscle, and along the exterior of its vessels, but in its nerves ; in its blood ; in the granules around the nuclei within the sarcolemma of its pri- mitive fibres ; nay, more, in the sarcous contents of these fibrils themselves: — in which latter disease, or repletion, or even (as in the uterus) a normal process of decay, some- FOEMS OF FAT IN THE BODY. 263 times causes a visible substitution of sarcode by fatty matter ; and analogy indicates a constant, though smaller, constituent of the same kind. The term "fat" is thus just as little of a specific appella- tion in a dietetic, as it is in a pathological, sense. Stored up in large cells as adipose tissue ; dissolved as a scanty ingredient in the blood ; entering largely into the delicate pulp of the nervous system ; and, lastly, formed within the sarcolemma by the regressive metamorphosis of the mus- cular substance or sarcode : — it is clear that fat constitutes no such single and simple physiological product, as would probably be amenable to the same solvents, or subservient to the same purposes, in the economy ; and would thus be susceptible of a common description. Looking to the adipose tissue, which certainly forms by far the largest proportion of the fat contained in ordinary meat, we find that its fatty substances are enclosed in large nucleated cells, the walls of which consist of a tough mem- brane probably of a chondrinous or gelatinous (rather than proteinous) nature, and therefore extremely difficult of solution. Hence its mechanical arrangement greatly op- poses its digestibility. The chemical composition of the fat contained in these cells seems no less influential. In other words, it is certain that all fats are so far difficult of digestion, as to be only taken up in small quantities at a time. And though it is customary to group the fats of the adipose tissue ac- cording to their predominant ingredients of stearine, mar- garine, and elaine — and especially to instance the first, the solid ingredient of beef- or mucton-suet, as being far s 4 2G4 ANIMAL FOOD. more difficult of digestion than either of the other two — yet I have been unable to meet with any facts on which this statement could be conclusively founded. On the contrary, experiments on digestion induce me to doubt whether there is any great inherent difference of these three neutral fats in this respect : all three being equally slow of digestion when enclosed in the adipose cell ; and even (so far as lean judge*) having no very diverse limit when set free from this investing membrane before being introduced into the digestive canal. In a purely animal diet, the due proportion of this oleagi- nous constituent is of indispensable importance. For, with the exception of that minute quantity of inosit (or muscular sugar) which is proper to the sarcous substance, the fatty matters contained in the various tissues of the body are the only representatives which this kind of food possesses of the two groups of the hydrocarbons and hydrates of carbon. Hence in such a diet, fat has to replace, as it were, the starchy ingredient of the vegetables which enter into a mixed diet. Fat thus constitutes the sole non- azotised element of animal food. And even in what are often miscalled vegetable diets, a large quantity of this animal substance is commonly added to the other ingredients of the food. At least there seems to be a strong impulse towards such an admixture in the most vegetarian nations and races of modern times : an * Any slight differences seem fairly referable to (1) the time demanded to melt the innermost parts of a solid suety mass in the digestive canal of the animal ; (2) the smaller general size (or, conversely, the larger relative surface) of the more margarinous and elainous fat-corpnseles : and (3 s ) the tougher and less soluble walls in which the larger stearmous cells enclos e their contents. DIGESTIBILITY OF FATS. 265 impulse well exemplified in the butter or ghee so copiously added by the Hindoo to the rice which forms his staple food. But though, as already stated, only a small quantity of fatty matter can really be digested at a time, any excess over this amount in the food being merely expelled from the intestinal canal with the faeces, it is impossible to assign an exact limit to the quantity capable of being taken up. Indeed there are evidences of very large variations of two kinds in this respect. That diverse kinds of fatty matter have very different degrees of digestibility, is only what we should a priori expect. And whatever may be the reasons for doubting this difference in the case of sub- stances so closely akin to each other as stearine, margarine, elaine, experience and analogy concur to affirm it of some other fatty matters, which are less uniform in composition. The complex composition of many fats; their volatile cha- racters; their acid reactions; their large oxygen constituent; and especially their admixture and diffusion in various fatty aliments, both with different members of their own class and with proteinous or even gelatinous ingredients : — quite explain why (for example) cod-liver oil, butter, palm oil, and stearine, are found empirically to be assimilable in very different quantities, and to possess a very different nutritive value. And into these variations merge others, which have a more general relation to the whole nutritional process, as shown in the effect of climate. Thus the quantity of fat habitually taken into the human system in the Arctic regions seems to be exceedingly large. And while this maximum of fatty aliment appears to account for that increased bulk 266 ANIMAL FOOD. which the fatty — and, as regards heat, non-conducting — layer beneath the skin of the body (jpanniculus adiposus) here seems normally to acquire, it must also be regarded as a necessary condition of that increased development of bodily temperature, which is obviously demanded in such latitudes. The large amount of heat evolved from the body in these cold regions ; the increased energy of that combustion on which this evolution of temperature de- pends ; the excess of oxygen, and deficiency of watery vapour, in the dense and frozen air ; and the expenditure of nervous (if not also of muscular) force thus implied, — all these circumstances concur to explain the vast pro- portion of fat which the Esquimaux or Laplander habitu- ally includes in his food; and the advantage which the European sojourner acquires by imitating the native in this respect. On the other hand, it is probable that this fat itself illustrates the other condition alluded to, in being a complex admixture of several rich fatty and proteinous materials, rather than one or two simple fats in a state of comparative purity.* * Pcmmican, a preparation of meat long known to the aborigines of Xorth America as the least bulky and perishable, as well as most nutritions, form of animal food, is made by drying the fresh muscular substance rapidly in the sun, at a heat probably ranging from 90° to 140° F. or more ; and then pounding it to a powder, which is next intimately mixed with an equal weight of adipose tissue. Presuming the process of drying to get rid of 60 or 65 of the 75 parts per cent, of water originally present in the fresh meat, the proportion of muscle and fat in the prepared pemmican may be regarded as approximating to that ratio (3 to 1 respectively), in which the two, when eaten fresh, are found by Arctic voyagers, best adapted to sustain health. But the lamented Dr. Kane has recorded his deliberate opinion that eyen this substance is far surpassed by the fresh meat of A animals, which in itself fulfils all the conditions above alluded to. EXCESS OF FAT. 267 A large excess of fat in the body often brings about pe- culiar modifications of that process by which this substance is consumed in the system. As before stated, the fat of the body may probably be referred to two sources ; to an addition of fatty matter from without, and to a meta- morphosis of protein from within. And there seem to be a variety of alimentary substances which, by economising or arresting the waste of the latter variety, produce many of the effects of the administration of the former ; so that, for example, the ingestion of albumen, starch, sugar, or even (though this is a doubtful illustration) of alcohol, tends to fatten the recipient scarcely less than if fat were itself given with the food. And hence an Esquimaux who eats (and contrives to digest) an excess of fat ; an animal fed exclusively on this ingredient of food ; a Goose or an Ox artificially fattened on starchy aliments ; and a beer-drinker who has acquired the typical obesity accurately depicted by Hogarth ; — all agree in some of the circumstances to which this excess gives rise. Of the fat thus accumulated, one part, varying greatly with their health and habits, is altogether consumed (p. 11) by the processes of life, and escapes from the body as carbonic acid and water. Another part escapes half-burnt, as fixed or volatile fatty acids ; which latter not only lubricate (and, if need be, defend) the skin, but fly off in variable quantities by the lungs. Hence an animal starved upon an unlimited allowance of fat increases in size during a short period. Its nutrition, however, soon suffers ; and it finally dies, with those ap- pearances of inanition already (pp. 37, 53) mentioned as attending all attempts to maintain life by the ingestion of 268 ANIMAL FOOD. only one ingredient of the normal food. In the later stages of this process of starvation, its body gives off* a repulsive odour, ascribable to an evolution of volatile fatty matters from its skin and lungs. And whether we are to regard these acids as derived from the fatty matters formed in its body, or from those taken as its food, they can only be referred to an imperfect oxidation of hydro-carbons, which have been abnormally accumulated in the organism ; and which are akin to the copious fatty tissues, and the oily excretions, natural (not to say essential) to various animals, and to Man in the Arctic regions. 5. The ash or inorganic constituent of muscle form- about 2 per cent, of its mass ; and, though consisting chiefly of elements which enter largely into the composition of other tissues, is distinguished from the ash of most of these by the proportions its several ingredients bear to each other. At any rate this is the case with the juice which pervades the muscular mass ; especially as regards the im- portant ingredients of sodium, potassium, phosphoric acid, and alkaline sulphates. Of these it is hardly too much to say, that their proportions in the ash of the liquor san- guinis are inverted in that of the muscular juice*; a difference which is all the more striking when we recol- lect, that it is necessarily opposed, and diminished, by that admixture of blood, from the vessels of the muscular mass, which forms an unavoidable impurity of the mus- cular juice. Thus, in this latter fluid, the alkaline sul- phates are reduced to a mere trace ; the proportion of potash is from two to five times greater, instead of from * Leliniann, Pliysiologiselie Clieniie. vol iii p. 91. INORGANIC CONSTITUENTS OF FLESH. 269 three to twenty times less, than that of the soda; the phosphoric acid is from twenty to twenty-five times that small fraction of the total ash which it offers in the serum of the blood; and, lastly, the chloride of sodium is reduced from three-fourths of the ash, as in the serum, to about one fourteenth or fifteenth. The import of this contrast remains at present un- known. But it is perhaps worth noticing that it is repeated with tolerable exactness, though on a smaller and less perfect * scale, in a comparison of the ash of the blood corpuscles with that of the liquor sanguinis. And hence, unless we could group together the living blood cell and the sarcous contents of the primitive muscular fibre, in some way quite foreign to all we know at present of their respective offices, it is to the plasma, and not to the muscle, that we must refer the chief share in this con- trast, remarkable as it is. The earthy phosphates must, however, be partially ex- cepted from this statement. Forming, as they do, a far (4 — 5 times) larger proportion of the muscular, than of * The following table exhibits this relation. The analyses from which it has been calculated are derived chiefly from the writings of Schmidt and Lehmann : — In 100 parts of Inorganic Substance of the Potash Blood Cells. Muscular Substance. Blood- liquor. 49 52 6 Soda .... 13 8 46 Phosphoric Acid . 18 68 6 Hydrochloric Acid 26 H 49 270 ANIMAL FOOD. the blood, ash ; their lime ingredient is smaller than their magnesia. But, if not in this respect, at any rate in its total earthy phosphate, the serum surpasses (2 J — 1) the corpuscles. 6. A series of secondary organic compounds completes the list of the muscular constituents. Kreatin, kreatinin, inosit, inosinic acid, lactic acid, belong to this group ; and seem to represent the progress of the sarcode towards two very diverse forms of decomposition. The composition of kreatin is closely * akin to that of urea ; to the construction of which it appears to be either a preliminary, or a collateral phenomenon, on the part of the azotised ingredients of the mass. Its quantity — about one part per 1000 of muscle — by no means invalidates this view ; especially if it be taken in conjunction with the small proportion of urea, and the trace of kreatinin, hitherto detected in the blood and in the muscular mass. The composition of inosit is that of sugar generally; and its amount too small to be determined. Lastly, the well-known composition of lactic acid, and its large quantity (about 6^ parts per 1000), concur with what has already (p. 12. et seq.) been said respecting the large non-azotised ingredient, and combustive or "respiratory'* destiny, of the protein-compounds ; midway between which compounds, and the ultimate carbonic and watery products of combustion, this substance is supposed to stand. The other constituents of muscle hardly demand notice in a chemical point of view. The watery and alcoholic extracts, for example, yielded by this mass include many * Compare the remarks and Table at p. 16. VARIETIES OF FLESH. 271 of the above ingredients ; in various gradations of admix- ture, which depend chiefly on their solubility in these two liquids respectively. The colouring matter, however closely it may be related to that of the blood, is sufficiently shown by the microscope to be quite distinct from it ; and to be seated in the sarcode, or within the sarcolemma, at an ap- preciable distance from the blood itself. Varieties of flesh. — In noticing these it is neither neces- sary to describe what everybody is acquainted with, nor possible to range over the wide field which is afforded by animal Life throughout the globe. We shall only allude to such of the commoner kinds of meat as are usually met with in civilised life ; with reference, too, to such peculiari- ties as Physiology can in some degree explain, without at all denying that there are many which it cannot. The contrast of striped and unstriped muscle is the first which strikes us. With a sarcous content of almost identical composition, the enclosure of this soft mass in the delicate wall of a narrow fusiform cell, instead of in a comparatively long and thick tubular sarcolemma, gives the elements of the unstriped muscle a greater amenability to the digestive process than those of the striped or volun- tary muscle. This advantage is increased by the mem- branous or flattened expanse which its layers usually assume. On the other hand, the smaller amount of its areolar tissue, and the close adhesion (and even agglutination) of its ad- jacent cells, often oppose great difficulties to their inter- stices being permeated by the solvent gastric juice, so as to allow their surfaces to be attacked by it. And when to this peculiar arrangement is added, as in the case of the gizzard 272 ANIMAL FOOD. of Birds, a massy thickness, the unstriped muscle must be regarded as relatively innutritious. It is, however, rarely used as an article of food, save in the form of tripe; which, properly cooked, is both digestible and nutritious. The striped fibre of the different kinds of ordinary meat also illustrates many of these collateral peculiarities. Apart from its preparation by cookery, it offers the greatest variety ; according to the particular muscles which it com- prises, and the condition (healthy or otherwise), age, sex, species, or class of animal from w T hich it is taken. For example, the close, tough, muscular wall of the heart — the muscular fibres of which are almost devoid of areolar tissue ; twining round and amongst each other, so as to prohibit all that relative movement of contiguous fibres or bundles which it is the sj^ecial office of the areolar tissue of other muscles to mediate and permit, and which is here rendered unnecessary by their consentaneous throb of contraction — this is, in all Mammalia, a nutritious, but indigestible, article of food. Nor is this absence of inter- stitial gelatin and fat to be regarded as merely barring the access of gastric juice to the surfaces of the apposed fibrils. On the contrary, that diffusion and admixture which these areolar septa imply, probably lend a material aid to the solution, as well as separation, of the bundles and fibres of the voluntary muscles, especially as prepared by cookery. Similar considerations may be deduced from a contrast of various other muscles. The tongue, for instance, shows a muscular substance, of which the elementary fibres, small, delicate, and branching, are intimately mixed up with a soft and ^uosi-nascent form of areolar tissue : as well as with a MEAT OF VARIOUS MUSCLES. 273 large quantity of adipose tissue. Hence the mass is at once very digestible, and extremely nutritious.* With a larger quantity of collagenic tissues, and with a greater density of these tissues themselves, the muscular substratum of the facial integuments shows a similar fineness of its fibres, and an intimacy of their admixture with the fat which mottles many parts of its red mass. It may therefore be regarded as possessing similar dietetic advantages. The large coarse fibres, and perpetual movements, of the respiratory muscles (as in the diaphragm and the abdominal wall) give them a twofold disadvantage (see p. 276); a disadvantage further increased by the tough areolar tissue, or tendinous fasciae, by which their bundles are separated and covered in. Any considerable admixture of tendon in its other forms is of course equally injurious to the general value of the flesh it helps to form ; not only by the less nutritive character of the admixture, but especially by its very diverse require- ments as regards solution almost frustrating any common process of cookery for the muscular and gelatinous tissues thus associated. Every housewife knows the difference between a beef-steak and a rump-steak ; between a sirloin and a sticking-piece ; between the under f and upper side of the loin. Disease, again, influences the nutritive value of flesh * The tongue and hump of a Buffalo are (no matter how tough its meat) delicacies for which alone the trapper or huntsman of the prairies often kills the animal — a reckless and melancholy waste of animal life, only paralleled by that wanton destruction of timber which is one of the most serious, though least noticed, of the changes wrought by Man on the surface of the earth he inhabits. f This, which in French gastronomies figures as the filet, is the piece T 274 ANIMAL FOOD. by means of circumstances easy to indicate. Taking the word " disease " in its vaguest and widest sense, its pro- cesses rob not only the muscular, but the fatty (and even, in a minor degree, the areolar) constituents of flesh, of much of their substance ; indeed, of their most elaborate and nutritive ingredients. Like repeated losses of blood, or starvation, most of the exhausting diseases seem specifi- cally to involve the albuminous material of the sarcode ; at the same time that they lower, or even change, the fibrin or syntonin, in addition to diminishing its quantity. Hence, quite apart from its proneness to putridity, and from those specific maladies which it has been alleged to ingraft on those who partake of it, the flesh of diseased animals is essentially innutritious ; besides being often tough, hard, and provokingly resistant to the mollifying influences of cookery. Age and sex, again, exercise a well-known influence. That the flesh of old animals is tougher than that of young ones ; and that an Ox, a Wether, or a Capon afford a more tender and succulent muscular fibre than do a Bull, a Earn, or a Cock respectively ; are facts which only require from science what it can hardly as yet give them : — namely, explanations, rather than a mere useless assent. Something of this kind may however be attempted. Thus it is said that the muscular substance of the young animal is richer in albumen. But except in so far as this richness is shared by the interstitial areolar tissue, it par excellence by which an English convalescent should begin his return to the national roast beef. It is said by French gourmets to be best helped towards due ''concoction'' by a moderate potation of Burgundy. FLESH INFLUENCED BY AGE AND SEX. 275 is difficult to see how it could increase the value (or even the digestibility) of the sarcode ; in which, so far as can be judged, this increase of albumen is compensated by an equivalent decrease of the equally nutritious syntonin. Hence we must seek some further explanation. In my opinion, such an explanation must be sought in the physiology of muscle, and even in its anatomy as distin- guished from its chemical composition. Premising that it is by no means unimportant to distinguish between what is most digestible, and what is really most nutritious — how far a given variety of flesh is capable of being dissolved, and how far its substance is of value to the organism when the resulting solution is taken up — I should offer the following explanation. While there are strong grounds for thinking that, in the young animal, and the castrated male, all the tissues are softer, more watery, and more soluble (i. e. more digestible), than in the adult, and in the male, respectively ; that the sarcode, sarcolemma, adipose tissue, areolar tissue, tendon, fascia, &c, are all less dense and resisting ; the size of the primitive fibril also seems to be in both cases of consider- able moment. In the young animal, for example, it is in- herently much smaller. And, in the castrated male, there is good reason to believe it is often incidentally so ; being more or less replaced and substituted by adipose tissue; which gradually comes to occupy the interstices of the muscular bundles and fibres, at the expense of their at- tenuated diameter. That such a change is not altogether a necessary result of the mere removal of the testicles ; but is a natural, though preventible, effect of a change in T 2 276 ANIMAL FOOD. the whole animal : is well seen in contrasting the flesh of a draught with that of a grazing-Ox. And a precisely similar (though greater) interstitial deposit of fat, concur- ring with an atrophy of the muscular fibres, may be seen even more distinctly in the muscles of healthy human limbs which have been disused from the mere inaction rendered necessary by fractures. The young muscular fibre is, however, the less equivocal instance of the two. And here it is desirable to remember that (1) the diminution of diameter is, relatively to the sarcous mass, an increase of its whole surface of exposure to the digestive solvent : and that (2) it is associated with a thinner and more delicate, # or more permeable, sarco- lemma. Conversely, as respects the muscle of animals inured to fatigue and toil, it must be remembered that not only is the sarcode condensed into a firmer, harder mass : which is further enclosed within what is doubtless a proportionally thickened sarcolemma ; but that, while its albumen is di- minished, and its effete extractive increased, its interstitial fat has also decreased ; at the same time that its areolar tissue and fasciae have shrunken into a more hardened, wiry, and contracted network of fibrous bands. Thus its proteinous element is impoverished ; at the same time that it is rendered far more difficult of solution : and is further deprived of those collagenic and fatty materials which help its solution indirectly, almost as much as they in- crease the total alimentary value of the mass. The chemical peculiarities of the flesh of different class* - of animals are as yet scarcely established. FLESH OF GAME. 2*7 The flesh of the various wild Mammals which form part of the group of " game " seems to possess many of the characters just noticed as producible by sustained exercise in their tame or domesticated congeners: such as a smaller amount of fat ; a narrower diameter of fibre ; a smaller albuminous constituent; and especially, a larger amount of those constituents recognised as making up the u ex- tractive." Together with these characters, however, such meat possesses others apparently more specific : — a richer and more complex .flavour ; a darker colour ; and a greater nutritive value, and even digestibility, than its mere analysis can at present explain. Doubtless many of these characters are essentially derived from cognate peculiarities of the creature's blood itself; which often shows similar, if not equal, differences ; and appears to dictate the quantitative relations of some of the muscular constituents with even greater regularity than might have been supposed.* Indeed, it would seem very probable, from the statements of the almost omnivorous hunters of America, that each genus, or even species^ of wild animal has a characteristic taste akin to that of its blood ; from which are derived, not only the flavour of the muscular fibre, but the correlative odour given off in the secretions of its skin and other organs. Similarly characteristic, but unexplained, are the differ- ences in the flesh of various Birds. The oily constituent of one species ; the fishy flavour of another ; the aroma of * or example, the relation of the water"of the serum and of the muscle seems (Lehmann, Op. cit. toL iii. p. 95) to survive even the enormous change of absolute quantity caused in both by cholera, T 3 278 ANIMAL FOOD. the Partridge, Pheasant, Grouse, and others of the game- fowl; and the offensive, noisome smell and taste of the carrion-eaters; constitute grounds of distinction, which analytical chemistry at present scarcely follows into the details it may hereafter furnish, decisively as it points to the differences of their food as a frequent and partial expla- nation. The flesh of the tame Birds commonly made use of in this country is said to contain less water and fat, more albumen and syntonin, and more of the kreatinous and allied compounds, than does ordinary meat. The muscular substance of Fish is equally diverse, as regards its appearance and flavour. The commoner and whiter kinds possess a flesh containing much more water and albumen, and much less fibrin and extractive, than does ordinary meat. And experience, which indicates Fish to be often more easy of digestion than the flesh of Mam- mals, though inferior to it in nutritive power, is only partially explained by the above deficiency, and by the comparative absence of fat and areolar tissue from the interstices of its muscular fibres. In some genera, as the Salmon, the flesh is much more oily. Bat here — probably from the close dense apposition of the fibres, themselves evidently containing a richer (and probably more copi> variety of syntonin — the increased value of the mass is associated with a greater difficulty of digestion. Some of these points are illustrated by the following Table, which is derived from analyses by Schloesberger, quoted in Simon's Chemistry (vol. ii. p. 525). BLOOD AS FOOD. 279 Ox-beef . Veal . . Pork . . Koe-deer Pigeon . Chicken . Carp . . Trout . Water. Fibrin Albumin -f vessels. -hglobulin. 77-5 17-5 2-2 79 15-6 2-9 78-3 16-8 2-4 76-9 18- 3-3 76- 17* 4-5 773 16-5 3- 80-1 12- 52 80-5 111 4-4 Extract. Alcohol -fsalts. Watery + salts. l"fi 1-25 17 v 1-3 1-3 •8 > Y 24 I- 1-4 1- 1-6 l-o 1-2 17 •2 (Albuminous) Phosphate of lime. Trace •1 Trace •6 22 Blood is so rarely made use of as an article of human food, save in that variable but small proportion which the microscope shows it to be incidentally present in all kinds of flesh, that its dietetic aspect would hardly deserve notice, save for the singular contrast it offers between what seems to be a highly nourishing composition, and a prohi- bition by which, for ages past, a large section of Mankind have been debarred from its use. Abounding, as it does, in the important protein-com- pounds of albumin, fibrin, globulin, and the like, its com- position would perhaps entitle us to regard it as a very valuable article of food. But experience seems to show that it has but a moderate value. And the repugnance shown by most races of Mankind, and even by many animals of prey, to feeding on blood, save under the extra- ordinary impulse of great hunger, must also be regarded as a suggestion of the same purport. Mechanically and chemically, we may find some plausi- ble explanations of this fact. First, it is too liquid a food ; T 4 280 ANIMAL FOOD. for., in some way or other, the stomach of Man, as well as of most Mammals, demands a solid condition of the ingesta, as alone affording a proper stimulus to its digestive acts. Next, the spontaneous coagulation of its fibrin is plausibly supposed to throw this compound into the form of a pre- cipitate ; the fragments of which, however small, are com- posed of layers densely aggregated to each other. The tough (and almost chitinous) composition of the walls of its corpuscles seems to afford a still more valid obstacle to the complete extraction of their rich albuminous contents. The utter insolubility of its large haematine constituent is another feature which I have found exceedingly well marked in various experiments on the artificial digestion of blood which I have instituted with the gastric juice of all classes of Vertebrata. Lastly, we may notice the che- mical deficiency of its hydrocarbons or fatty constituents ; as well as the contrast offered by its salts with those of the muscular substance: — a contrast which renders them a very insufficient means of supplying, as regards these im- portant inorganic constituents, that waste of substance which the food ought to compensate. (Comp. p. 268.) The brains of animals consist of a scanty admixture of membranous and areolar tissues, and of a large quantity of vessels, with the structures proper to these nervous centres : namely, nerve-tubes and ganglion-corpuscles. Hence, as regards its composition, the rich and elaborate albuminous and fatty contents of these structures constitute them highly nutritious articles of food ; while the delicacy of their membranous walls offers little obstacle to the access of the various digestive agents to their interior. They are thus GLANDS AS FOOD. 281 excellent articles of food ; especially when mixed with other substances capable of affording the requisite mechanical stimulus to the digestive organs. The various glands possess a dietetic value which is derived^ partly from their physical structure and arrange- ment, partly from their chemical composition. Thus, on the one hand, the dense mechanical texture of the liver and kidney oppose their usefulness as food, by rendering them comparatively difficult of digestion ; while, on the other hand, the bile and urine which they respectively con- tain, necessarily superadd the properties of these secretions to those of the proteinous parenchyma that forms the bulk of their mass. Hence the liver, with its fatty ingredients, and recrementitious bile, is far more nourishing than the kidney ; which is not only deficient in hydrocarbons, but contains a certain quantity of urea, demanding a speedy excretion. In like manner, from both mechanical and chemical reasons, the pancreas (p. 178) is highly diges- tible and nutritious. The hard solid texture of bone, and the predominance of its gelatinous and calcareous constituents, together render it of comparatively little use as an article of human food. The eggs of oviparous animals contain, in addition to the embryo itself, a quantity of nutritive matter, which is •destined for its nourishment during the process of incu- bation. Hence, the large eggs of many Birds form an excellent article of food ; the dietetic virtues of which re- semble, to some extent, those previously attributed to milk. The white of egg contains about 15 per cent, of albumen. The yolk is composed of about 20 per cent, of the same 282 ANIMAL FOOD. protein-compound ; together with about 30 per cent, of fatty matter — chiefly margarin and elain — in a state of subdivision and admixture which eminently adapt it to digestive purposes. Milk. — The general composition of the milk which forms the food of the young Mammalia has already been mentioned. It only remains for us to notice its chief varieties, and some of the articles which its artificial pre- paration adds to the bill of fare of the human adult. The changes by which, late in the period of gestation, the hitherto albuminous fluid contained in the mammary gland is converted into milk, are foreign to the purpose of this de- scription. ; though it is interesting to point out that not only the casein, but even the butter and the sugar, of the true secretion seem to be produced by a metamorphosis of the albumin previously present.* Nor need we dwell upon the composition of the colostrum or bie$tin the food and exercise of the animal secreting it, — being increased by the ingestion of much starchy matter, di- minished by exercise — but seems to differ materially, both in its total amount and its several ingredients, in different species; and to possess a composition which not only permits, but even implies, its speedy conversion into a variety of new fatty compounds at ordinary tem- peratures. The butter of Cow's milk, for example, stated by Bromeis to contain about 6*8 per cent, of margarine, with 30 of elaine, and 2 of a fatty matter specific to butter. The latter, closely related (if not identical with) the " butyrin w of Chevreul, seems to be an impure neutral fat; the acid of which is united, as butyric BUTTEK. 289 acid, with the base of glycerine. In the butter of human milk, its amount is much smaller than in that of the Cow ; in which, according to the statements of many chemists, it often materially exceeds the above estimate of Bromeis. But the exact nature and admixture of the fatty consti- tuents of the milk probably varies even in different specimens. The marked flavour and odour imparted to ordinary butter by peculiarities of the Cow's food — the strong taste derived from turnips, and the delicate fragrance of fresh butter from Alpine pastures — conclusively show that various ingredients are thus transferred from the food to the milk. In like manner, butter not only easily becomes rancid from undue warmth and exposure, but the products of this decomposition vary according to the temperature, and the access of oxygen, by which it is accompanied. Such circumstances often add to the ori- ginal ingredients of the buttery mass a variety of fatty acids ; many of them highly volatile ; and distinguished by the names of caprylic, butyric, capronic, capric, vaccinic, and the like. How far the dietetic value of butter is connected with this complex fatty composition, and proneness to oxidation, can scarcely be definitely decided. But, whatever the theory of its value, it is impossible to doubt the fact ; and not easy to rate that value too highly. Thus much may at any rate be alleged in its favour ; that it is not only the most natural, but by far the best, form in which hydro- carbons can be introduced into the healthy human or- ganism. Attractive to the taste of most persons, and easily assimilated by children, as well as by adults whose u 290 AXIMAL FOOD. delicate organs of digestion resent the introduction of fat in the form of the ordinary adipose tissue of animal food — it is probably, weight for weight, and taken in moderation, the most economical, because the least wasted, of all the constituents of our ordinary mixed diet. Of course, the quantity absolutely consumed must be distinguished from that merely taken into the digestive canal ; and will vary with the nature and amount of the other ingredients of the food, as well as with the rate at which nutrition (and especially combustion) proceeds in the body. But the large amount of this substance habitually taken as ghee by the Hindoos, and the huge ration of butter of the Alpine dairy-men and wood-cutters in the Tyrol — often little less than a pound daily — are a striking testimony, both of its harmlessness to the digestive organs, and (considering the simplicity of their food in other respects) its value to the system in general. Indeed, the diversity of climate and habits thus shown to be compatible with its copious use, suggest for it some direct relation to those two organs — the skin and the lungs — which presumably boar the chief stress of the Indian and the Alpine climates respectively. Cheese. — The substances known by this name cons chiefly of casein, which has been precipitated from the milk in company with a variable quantity of its buttery constituent. Their dietetic value is of course very high. But their digestibility varies greatly: according to the pro- portion of fatty matter and salts which they contain, the mechanical aggregation of their mass, and the degree of decomposition which they may have experienced sub- sequently to their manufacture. CHEESE. 291 Thus as regards its admixture of butter, while the com- position of a particular variety of cheese is doubtless affected by that of the milk which yields it, the proportion of this ingredient is much more dependent on the process of cheesemaking. For in making some cheeses, as Stilton and Neufchatel, the milk used is enriched by the addition of cream, which thus enters largely into their composition. In others, as the Cheshire, Gloucester, and Emmenthaler, the milk is used pure. In others, the cheese is prepared from a milk which has been skimmed or deprived of its cream ; of which class the Grruyere, as an excellent cheese, is perhaps the least invidious illustration. The precipitation of casein to form cheese is generally effected by the addition of rennet, the mucous membrane of the true stomach or abornasum of the calf. The solu- tion of pepsin (compare p. 120) thus added precipitates casein by virtue of a specific property of this kind; and not from its acidity, or even from its supposed power of causing the sugar of milk to undergo a metamorphosis into lactic acid. For the pepsine may be added, almost in a state of neutrality to test paper, without losing its effect. And whatever influence of this latter kind may be gra- dually brought about, the rapid solidification of the casein of milk by an addition of as little as ^-^J-^th * of its weight of rennet, and the similar precipitation of dissolved albumen, together leave no doubt that the solidity assumed * Mitscherlich (Bericht der Akademie der Wissenschaften zu Berlin, 1842, p. 147, et seq.) states this proportion of pepsine as sufficient. Ber- zelius found smooth the weight of the coagulated casein had been dissolved out of a piece of rennet during the process of precipitation. ks 2 292 ANIMAL FOOD. by the casein of milk is a specific effect of the pepsine itself. In consonance with such an opinion we may notice that, in respect to the salts of ordinary cheese, the chief distinction hitherto established appears referrible to the way in which the casein has been precipitated from its solution in the milk. Where the process has been effected by the addition of rennet, the caseous deposit contains a large proportion — about 5 or 6 per cent. — of phosphate of lime. But where the precipitation has been produced by the lactic acid which is gradually developed in milk as the result of its own spontaneous decomposition, the de- posit contains scarcely one per cent, of this salt. In such a case, however, the smaller amount of phosphates appears to be partially compensated by the presence of some free phosphoric acid, Some of the characters of various kinds of cheese seem to depend upon details of composition, or of preparation, at pre- sent unknown. Among the latter, the amount of rennet used to coagulate the milk, and the temperature and mechanical pressure to which the curd is afterwards exposed, are doubt- less the most influential. In general terms, the free addition of rennet renders the cheese far more digestible, as well as nutritious ; not only from the*completeness with which it precipitates all * the varieties of casein present, but from its antiseptic (perhaps even from its digestive) qualities, and from the above composition of the salts in cheese thus made. The spongy structure sometimes met with in English cheese, and more uniformly found in the Gruyere, Parmesan, and Emmenthaler cheeses, suggests an * Compare pp. 2 $7, 288. CHAXGES IN CHEESE. 293 interstitial evolution of gases, forming cavities which the pressure of the contracting casein subsequently fills with a rich extractive liquor. But it is probable that the earlier application of mechanical pressure would prevent these cavities from being formed, at the same time that it would render the cheese somewhat poorer as respects those fragrant and savoury substances which the liquor thus pressed out of it would contain. Hence, supposing these cells — thraenen and augen (tears and eyes) as the Germans sentimentally term them — really correspond to a smaller proportion of rennet, a more spontaneous precipitation, and a more pronounced decomposition of the cheese, the increased surface, and richer extractive, they imply are digestive advantages ; which are counterpoised by a greater poverty of salts and of casein, and a greater proneness to decomposition, than is possessed by their analogous English cheeses made from milk only. The changes which cheese undergoes by keeping are chiefly manifested by the formation of various volatile fatty acids, which generally communicate their characteristic odour to the whole mass. Such alterations are usually most marked in those varieties of cheese, in which but a small proportion of rennet has been used, and much fatty matter is present. Hence they seem at least partially at- tributable to a metamorphosis — probably an oxidation — of the buttery constituents themselves. In addition to this change, however, the casein also undergoes a somewhat similar fermentation ; which is accompanied by the pro- duction of oxides of casein, and of volatile fatty acids. Oc- casionally the process is carried so far, as to constitute a u 3 294 AXIMAL FOOD. kind of putrefaction, in which part of the nitrogen origi- nally present is given off in the form of ammonia. The highly poisonous properties which decayed cheese sometimes possesses, and the repulsive odour which it often gives off, are illustrations of these statements. The value of cheese as an article of food may be to some extent inferred from the large amount of its proteincus con- stituent, which often forms more than 70 per cent, of its whole weight. This quantity of casein would correspond to about 11| per cent, of nitrogen : a quantity far beyond that contained in any other ordinary variety of azotized food. But just as this unprecedented chemical composition may suffice to indicate how largely such a proportion of the " histogenetic " principles would require to be di: with the "respiratory" or "combustible" substances, in order to constitute a "food"' in the true acceptation of term, so it partially explains the fact that cheese ifl i thing but easy of digestion. By many persons, even milk is only digested with difficulty: so that much of casein which is at once precipitated from it in the stomach by the gastric juice, and thus acquires all the mechanical advantages of a solid food in stimulating this organ, i be subsequently traced through the whole length of bowels, but little changed by the action of the juice. And the mechanical aggregation of many kinc cheese — their extreme hardness, dryness, and density — often enable them almost to defy digestion.* But minute * Blonifield in " The Fanner's Boy." thus alludes to a kind of cheese — " Which in the hog-trough rests in perfect spite, Too big to swallow, and too hard to bite I " VALUE OP CHEESE. 295 division, cooking, or careful mastication, will obviate one of these objections. And the other is easily met by a proper admixture of vegetable food. With such precautions, cheese becomes a most valuable article of food; so that we need be little surprised to find the extreme value and importance assigned to this variety of azotized aliment amongst rural populations where meat is scarce and expensive. Indeed, the diet on which tradition states old Parr to have attained his remarkable age can hardly have been very unwholesome. And the natives of a country which, like ours, still boasts of large cheese-fairs in some of its country towns, can find little to wound their national pride in the quaint fancy of Joh. v. Mueller ; — that, where cheese is largely manufactured, there freedom flourishes.* * Frericlis(0p. Oit,). V 4 296 CHAP. VIII. VARIETIES OF FOOD. VEGETABLE FOOD. Vegetable Food. — Its Characters. — Its importance to "National Life. — Its Value in warm Climates. — Its Variations ; caused by Culture. Climate, Age. — Cereal and allied Grains ; their Value as referrible to their Growth, their Composition. — Proximate Analysis. — Variations in their Proteinous Constituent, Husk, Fat. Starch. Sugar, Salts. — Varia- tions in other Characters. — Process of Bread-making. — Physical and Chemical Changes. — Choice of Breads. — Leguminous Seeds. — Compo- sition. — Nutritive Value. — Potatoes. — Their Composition. — Their Nu- tritive Value. — Roots and Fruits. — Their Composition and Uses. — Shoots, Leaves, &c. — Their Composition and Nutritive Proper* The nutritive characters of vegetables generally have already (p. 251) been alluded to by way of contrast with those of animal food. A redundancy of the hydrate* carbon ; a deficiency of hydrocarbons and proteinous con- stituents ; and a more frequent (though more variable) deficiency of salts — these were the chief peculiarities found in the class of vegetable aliments as a whole. It is hardly necessary to add 3 that there are many and large exceptions to every one of these rules. The very moderate starchy ingredient of various fruits, and even seeds ; the oil of the olive or cocoa-nut : the large albu- minous element of most kinds of pulse : and even the A^aluable saline ingredients of various herbs used as food : — these examples may suffice to indicate how little the VEGETABLE FOOD ESSENTIAL. 297 general characters above summed up, will apply to all vegetables in detail. The so-called " vegetarian " system can just as little be deduced from the economic, as from the practical, aspect of Nutrition. But the half-truth which it, like almost every other error, may be said to contain, is both in- teresting and suggestive. Eestricted to a carnivorous diet, Man could scarcely have fulfilled the divine command of replenishing the earth : or at any rate, only with so wide a disparity between his numbers and those of the brute creation, as would have deprived this mandate of most of its significance. It is only the few and scattered inhabi- tants of a primeval forest, or of an Arctic waste, which has ever been known to live exclusively, or even chiefly, on flesh. The dawn of agriculture is co-eval with the be- ginning of civilization : the neglect of it, if persistent, first restricts the numbers, and finally seals the doom, of any nation. Doubtless, many a race has thus silently dis- appeared from off the face of the earth ; to leave, it may be, no traces save those found in the Folk-lore of Dwarfs and Griants. And though, in legendary story, the might of invaders is the alleged cause of such a decay and extinction, it may be fairly questioned — as indeed it might be left to our own times to answer — whether the conquerors have really ousted the aborigines by force of arms, or by that commissariat, which, other things being equal, would decide any campaign ; and which, in a struggle protracted through many years, must swell the numbers, as well as strengthen the individual forces, of those who adopt it. The exclusively carnivorous habits of the cattle- 298 VEGETABLE FOOD. slaying Ghianches are clearly the offspring of rare and temporary circumstances ; so unusual, and so temporary, as to form no real exception to this rule. And while the Arab and the Tartar nations seem to have added more agriculture to their pastoral pursuits than has usually been supposed — the attention of history having naturally been fastened on their peculiarities, rather than on their resemblances to other nations — their predatory habits and repeated migrations have essentially confirmed this rule; and their numbers, disproportionately small when contrasted with those of nations whose ancestors mingled with their own on the plain of Shinar, have only attained the slender proportion they now possess, by the fruits of perpetual pillage on the one hand, or by something like a systematic adoption of the agricultural customs of the nations whom they have displaced, on the other. The pasture of flocks is indeed but a partial substitute for the tillage of the ground, suited only to an early epoch of civilization, and a sparse population. The milk and flesh thus yielded as the sole harvest of a large tract of land are themselves an insufficient nourishment, with- out the addition of some vegetable food. And an exclu- sively flesh diet seems even more rare and unwholesome, in all save Arctic regions. In warm climates, for example, its fat appears to be scarcely digested ; and its protein is in decided excess. And while its superfluous flit tends to surcharge the liver and the lacteals, as well as to derange the alimentary canal, its albuminous compounds often appear to bring about a feverish state of the system at large. Perpetual exercise in the open air, and compara- ITS SUPERFLUITY HARMLESS. 299 tive moderation in eating, seem to be the only means of carrying on healthy Nutrition with this unsuitable quality of food. It may be further conjectured, that there is a wide difference between the digestive risks which attach to those superfluities of protein, or of starch, respectively, which are ordinarily associated with the use of a pre- dominantly animal or vegetable food. The excessive inges- tion of protein in a warm climate seems to be sometimes injurious, by the unchecked continuance or progress of that decomposition, which the gastric juice in larger quantity would specifically arrest. Compared with this, an excess of any of the ordinary hydrates of carbon seems of little importance. Indeed it may be surmised that, to a healthy digestion, any moderate surplus of starch is almost in- different, if not absolutely useful by the mechanical stimulus it affords. At least so much of this substance may always be found unchanged in the faeces derived from even a mixed diet, that it would seem that much of the starch which the digestive juices fail to render soluble, and to absorb in the form of sugar, escapes all metamorphosis whatever. But on the other hand, many varieties of dyspepsia indicate that it is so far one office of the healthy digestive juices to restrict the changes of the warm and moist starch contained in the alimentary canal, as that their insufficient quantity, or depraved quality, permits a large formation of lactic acid, ending in the evolution and expulsion of various gases. (Comp. pp. 239, 240.) More variable than the tissues of the animal body, the innumerable structures included under the term " vegetable food " differ materially from each other in almost every cir- SOO VEGETABLE FOOD. cumstance and quality. Occasionally yielded to the wants of Man in quantities and qualities such as enable him to feed, with scarcely any more toil or trouble than does a frugivorous monkey of Western Africa, they generally illustrate the primeval curse by demanding so careful a cul- ture, that it is only "in the sweat of his brow " he can "eat bread." And every detail of this artificial process of their cultivation materially affects the value of the food they form. Nor are the natural circumstances of the vegetable itself less influential. The ingredients of the soil, from which the plant is in great part nourished, greatly in- fluence its composition ; so much so, that any serious deficiency of these organic and inorganic materials, how- ever gradually brought about, prevents the growth of the embryo plant, or permits its premature decay and destruc- tion at some further stage of its life. Climate, again, is no less influential : dictating, as is well known, the very life of many plants ; and materially influencing the nutri- tious qualities of those whose greater hardihood survives a wider range of latitude or level. And a whole series of changes of composition are well known to occur in the history of most esculent vegetables. The young plant, or the young shoots of a plant, are not only far more easily digested than are the harder and less soluble textures of the older vegetable organism, but are often much richer in nutritive matter. The approach of fruits towards their maturity determines a converse change in two parts of their structure : the pulp undergoing a series of physical and chemical changes, which have the result of rendering it far more nutritious; while at the same time the core CEREAL GRAINS. 301 or stone within becomes harder and less nutritious. In short, Man's observation, choice, and artificial treatment, together exercise an almost unlimited sway over this kind of food ; and, through this, materially influence his own mental and moral destiny. The very same selection of soil, climate, treatment, which increase the per-centage of protein in a given weight of the grain grown under their influence, will necessarily extend their influence, in some degree, to every person and animal whose food is formed by the resulting crop. Com. — The seeds of the Cerealia are not only the most important of all the varieties of vegetable food, but may even be ranked above all other alimentary substances, animal as well as vegetable. Such an estimate of their value may indeed be deduced from the history of Mankind in all ages : and is well expressed by that phrase " the staff of life," which is applied to one of their chief products when prepared as food. The explanation of this remarkable fact may no doubt be partially found in circumstances which are compara- tively independent of the characters ascribed to these seeds by modern chemistry. Hardy and tractable, the various plants which yield them have been carried by Man over the whole earth, with the result of his finding no latitude or climate in which one or other of them will not grow readily : up to the very border of the Arctic circle ; or to a level, in Europe of 5000, in Asia of 7000 or 8000 feet, above the sea. Evading the extreme rigour of the seasons by their brief, but variable periods of growth; 302 VEGETABLE FOOD, finding nutriment in most soils ; capable of largely varying some of their inorganic salts with little detriment to their vigour or usefulness ; and exhausting the soil less quickly than many other plants ; the numerous members of the cereal class constitute the chief element in the dietary of civilization :— a food, the habitual use of which is not only compatible with the highest development of social life, but almost demands, for its successful production, a state of comparative well-being, both political and general. But a far better explanation of this great dietetic value of the Cereal grains is to be found in their composition ; which, imperfectly as we are still acquainted with some of its details, gives a sufficient clue to their general and special characters as articles of food. In all these seeds, the nutriment stored up for the embryo which they con- tain, exhibits a considerable resemblance to milk ; both in the nature and the proportion of those various alimentary principles of which it is composed. It is true that the substance of the grain contains little fat ; while conversely, it includes a large insoluble ingredient of husk and cel- lulose, absent from the milk. But, allowing for these peculiarities, and for an excess of starch which may be looked upon as in some degree compensating the above want of fatty matter (compare p. 62), the alimentary composition of the two is so far akin, that we may fairly estimate a pound of good bread, with two pounds of a tolerably pure spring water, as equivalent, for the nutritive purposes of a healthy adult, to about two or three pints of milk. COMPOSITION OF VARIOUS GRAIXS. 303 The proximate analysis of the various grains chiefly made use of in Europe may be summed up * as follows : — 100 parts dried at 212° Fahr. Protein, Glutin Cellulose, Gum. Ash. Moisture Wheat ; average of + Albumin. oLcii cn • Sugar, Husk s per cent. seven kinds . 16-9 55-3 22-7 1-8 14-2 Rye ; average of four kinds . 16-03 51-97 27-74 1-47 14-06 Barley ; average of three kinds . 15*89 40-17 43-66 3-87 14-43 Oats ; average of two kinds . 15-08 37-41 45-67 3-67 11-2 Maize ; average of f 12 " 67 1 two kinds 14-16 72-04 < of which V L 3— 4 fat J 1-39 14-16 Rice 7'4 86-21 539 •36 15-14 Buckwheat ; average of three 9-17 54-76 34-24 1-09 15-12 In addition to these grains, with which have been in- cluded, for the sake of convenience, some foreign to the Cereal group, there are many other Graminceous seeds largely made use of as food in various parts of the globe ; especially the varieties of Millet, (Panicum,) which are largely cultivated in southern Europe, and Asia; those of the genus Sorghum, in India and Africa ; of the Poa in Abyssinia, &c, &c. The circumstances which dictate the preference of some of these kinds of grain often seem to be quite as much related to the poverty, or ignorance of agriculture, of the nation using them, as to their indi- * Chiefly from Horsford and Krocker's analyses, (Annalen der Chemie ti. Pharmacie, Bd, 58, s. 166, 212) ; in which the protein, estimated from the nitrogen present, is probably somewhat overrated. 304 VEGETABLE FOOD. genous character, or their suitability to the climate and soil. As regards the more valuable and widely-used grains, though most of them seem to have been carried with the diffusion of the human race from the neighbourhood of Asia Minor, they show considerable contrasts in their range of climate. Maize, for example, demands more heat for its complete ripening than can generally be obtained north of a latitude of 40° or 45°. Eice, which within the tropics ranges to a level of 5000 or 6000 feet above the sea, re- quires not only heat, but copious moisture : such as is usually supplied by irrigation of the lowland plains and plateaus, in which it is best cultivated. Wheat perhaps shows the widest range of all; though Eye, Barley, and Oats, are all said somewhat to surpass it in endurance of cold, as well as in facility of ripening during the brief sum- mer of high latitudes and levels. With these circumstances of their culture are doubtless connected many of the points suggested by a contrast of their composition. In all the above grains, the proteinous constituent forms a considerable proportion of their weight. And on the whole, the steady diminution of this ingredient seen in the above table — in which the 17 per cent, of protein, contained in wheat (often rising to 20, or even 24 in the richer and better varieties) gradually drops to much less than half this proportion in Buck-wheat and Eice — evi- dently corresponds with the relative nutritional value which is usually assigned to them. In respect to the varieties of this proteinous ingredient present, we can scarcely trace any analogous difference. For though we rind substances closely resembling all three of its chief modifications in INFLUENCE OF COMPOSITION. 305 the animal kingdom — for example, in Wheat, a large quantity of gluten and vegetable fibrin, analogous to casein and fibrin respectively, and a small quantity of vegetable albumen — still their relative proportions in the different Cereal grains are at present far from being accurately made out. We should be wrong, however, to attach too exclusive or predominant a value to any scanty variation of protein, especially in that absolute form in which alone such a varia- tion is indicated by the above table. The contrast in the proportion of insoluble cellulose and husk is scarcely less important ; and is well illustrated by that high per centage of this ingredient which is notified in the analysis of Barley and Oats, and which concurs with what is, empirically, a well- known inferiority of these seeds to those of Wheat as food. It is true that, in the rich and abundant food of the affluent, the insoluble elements of the food are sometimes unwit- tingly reduced below their due amount ; so that the func- tion of digestion in some degree languishes for want of the proper mechanical stimulation of the alimentary canal by such substances. But excess, either in quantity or quality, has never been the dietetic error of the mass of any nation. And hence the total solubility of a given grain — in other words, the total quantity of its assimilable parts, compared with that of its husk — would, other things being equal, generally dictate its preference as a staple article of food. In like manner, we may probably find the alimentary ratio of the starch, less in its absolute per centage in the dry grain, than in its proportion to the protein. So that, for example, in contrasting Wheat and Eice in this respect, we 306 VEGETABLE FOOD. may look upon the starch of the latter as being from three to four times more abundant than that of the former (11*65 against 3-27). Fatty matter, sugar, and even salt, doubtless require somewhat the same estimate. The four per cent, of fat found in Maize, is thus a far more im- portant detail of its composition, than its mere numerical amount might imply. And the variation in the above Table of the salts, which range from a multiple of one in Eice, to ten in Barley, may suggest the same remark. The salts of these grains (see Table*) deserve separate Wheat ; average of 4 analyses . Kye ; average of 2 analyses . . Barley ; average of 3 analyses . Oats Maize .... Buckwheat . . Ash containing per 100 parts. Potash. Soda. Lime. Magnesia. Iron(oxide). Silica. Phosphoric Sulphuric acid. acid. 22 01 MUo 31) 21G6 (11 to 32) 12-86 12 9 11 (A to 28) 11-61 (4 to 19) 7-92 272 4 95 2 42 3-7 13 607 10-76 10-22 8-52 77 17- 1039 •9 1-35 17 1-3 1-05 •99 1-C6 2625 53-3 •8 •69 15-27 4$ 92 39*64 14-9 50-1 50- 15 •07 •34 •14 I- 2 17 30-8 875 1 20*13 allusion ; not only from their contrast in the several kinds of grain, but even in those varieties and specimens of the same grain hitherto analyzed. When two varieties of Wheat show, the one potash, the other soda, to be the alkaline base almost exclusively present, we at once recognise a contrast which, whatever its influence on those who use either grain as food, admits an easy explanation as * From various analyses by Bichon, Fresenius. Letellier, Erdmann, "Will, Boussingault, and Koeehlin, in Moleschott's and Freriehs' works, already cited. INFLUENCE OF PHYSICAL CHARACTERS. 307 regards its source ; and indicates that under circumstances otherwise favourable, the preponderance of either base in the soil is almost indifferent to the plant. But in the vast amount of phosphates contained in all the class of grains, as contrasted with the very moderate quantity of the same salts in many other vegetable substances, we may recognise one main element of the great value of this kind of vegetable food in supplying these large inorganic consti- tuents of the blood, the muscular substance, the secretions, and the skeleton. And the coincidence of a large excess of silica, in the ash of Rye and Barley, with a marked diminution of the phosphates, suggests another reason for that lower nutritive value which experience has assigned to these hardy (and otherwise valuable) grains. It is probable that other and more mechanical details are often concerned in the preference of certain Cereals ; and are, indeed, related to the above composition. The facility with which a particular kind of grain is stripped of its husk ; as well as the arrangement of this ingredient ; the ease with which it ferments ; the expansion it under- goes in doing so ; the flavour it has, or acquires ; the de- gree in which it will keep when prepared as bread ; — all of these characters, as well as those already mentioned re- lating to its climate and soil, are doubtless of influence in the selection of this or that grain. Indeed, most, if not all of them concur in that preference for Wheat, which has for ages been established among the more civilized nations of Europe. Eye-bread, for example, has a crumbly cha- racter, which gives it a digestibility — though scarcely a surface — almost approaching to that which renders spongy x 2 308 VEGETABLE FOOD. Wheaten-bread so valuable in domestic economy. It keeps fresh, too, considerably longer. But almost all the fermented preparations of the other Cerealia seem far behind Wheat in both these respects ; so that, for example, one cannot doubt the soundness of the American rule of eating ripe Maize almost exclusively in the form of ex- temporised cakes ; since, as bread, it often sours in a single day of moderate temperature. The rationale of bread-making may be briefly sketched as follows : — The ordinary preparation of flour from these different kinds of grain is such as to introduce some slight chancres of composition. For the processes of grinding and sifting strip away the outer husk of the grain ; and thus have the disadvantage of removing a part of it, which contains a larger proportion of protein than does its more starchy interior. The subsequent process of fer- mentation and baking converts part of the starch into sugar and alcohol, with the formation of carbonic acid gas. The slow extrication of this elastic fluid gives the bread a porous or spongy character ; which has the ad- vantage of greatly increasing the effective surface that is subsequently exposed to the action of the digestive fluids. Part of the gluten of the flour is also lost in the process. But the whole amount of both gluten and starch which disappears is not very considerable: probably not more than 5 per cent. This trifling loss, and the addition of about 30 per cent, of water, constitute almost the only noticeable differences between the composition of pure Wheaten-bread, and that of the flour from which it is BREAD-MAKIXG. 309 made. Their effect is, to exchange the composition already mentioned in speaking of Wheat, for about 16 per cent. of protein, and 35 to 40 of starch, in bread of a moderate dryness. But the advantages afforded by the spongy texture, and the intimate admixture of water, which are brought about in the process of making bread, are still further increased by a mechanical change produced in the starch-granules themselves. For, under the influence of the moisture to which they are exposed, most of these swell up and burst; and thus place their contents in a state much more accessible to the changes which are sub sequently induced in them by the salivary and pancreatic secretions. In the preparation of ordinary bread, the carbonic acid extricated from the fermenting dough is the means of giving it a spongy character ; the evolution and expansion of this gas being furthered by the heat of baking. But in various other kinds of bread, a similar sponginess is brought about by the same gas being set free from a carbonate of an alkali, — usually soda or ammonia, — either by the addition of an acid, or by the acid developed from some sugary constituent — as a syrup — also added to the dough. Of such unfermented breads, that formed by the effervescence of hydrochloric acid and carbonate of soda seems prefer- able ; from its only adding to the resulting food a salt, — the chloride of sodium, — which necessity or habit otherwise requires to be mixed with the dough. But Dr. Dauglish has recently patented an ingenious process, which seems far superior to all these methods. It consists in forcing into the dough a quantity of free carbonic acid under a z3 310 VEGETABLE FOOD. heavy pressure. Since the bread thus made loses none of its starch, dextrin, or sugar, as in ordinary fermentation ; and also avoids an admixture of acids and alkalis re- quiring more nicety of adjustment than can perhaps be expected in any class of workmen unused to chemical operations, it promises the advantages of a strictly "pure" bread ; made with a saving of alimentary materials such as ought to render it cheap to the public, as well as re- munerative to the inventor. It further appears to keep somewhat better : a circumstance which, if confirmed by observation, will scarcely be a smaller recommendation; and will probably find its explanation in the absence of that fermentative process which, in ordinary bread, con- tinues even after the process of baking is finished. The peculiar sponginess of wh eaten bread is ascribed, with good show of reason, to its large quantity of tenacious gluten retaining the bubbles of carbonic acid as they are evolved in its interior. And in various breads made of starchier meal, — Eice, Arrow-root, &c, — a similar tenacity is sometimes conferred by the addition of albuminous sub- stances, such as eggs or milk, which enable the dough to rise like that of ordinary bread. The important question, as to what is the best bread, is one which many persons would doubtless decide for them- selves ; with answers the diversity of which would recall the adage, " qaot homines, tot seiitentioj" Whether a bread artificially whitened and adulterated — drugged with alum, lowered by potato starch, damaged by ground-bones, or what not — is really the best, we should perhaps be told to leave for experience to decide : just as some would assert FAULTS OF WHITE BREAD. 311 that it is not for immutable morality, but for fluctuating custom, checked by competition, to determine whether it is right or wrong for any particular retail trade secretly to adopt new standards of weight, or new interpretations of such complex words as " bread," " milk," " coffee," &c. But inasmuch as bread is the staple of food for a large proportion of that labouring class which forms the very thews and sinews of society, or the broad basis of the whole social edifice, its proper appraisement deserves to be under- stood. It is usually asserted that modern experience has taught the labourer the economy of white bread. If so, then science and experience might for once be almost excused joining issue. That, weight for weight, pure white bread would yield to a labouring man a trifle more starch, perhaps even more sugar, is possible enough. But, as already mentioned, the chemist and the microscopist concur in assuring us that those outer layers of the grain thus rejected from the bread-making process contain much more of the proteinous ingredient than do the inner or nuclear portions. Physiology, too, finds this very de- ficiency to be one which the habits of our labouring classes no way compensate ; so little indeed that (as Dr. Carpenter . has well suggested) the present epoch may almost be dis- tinguished, dietetically, as one which favours a rheumatic diathesis in the masses of our population by an over-starchy and insufficiently proteinous food. And, as a Hospital physician, I would add to this statement, that the im- mediate effects of these dietetic faults, in the shape of special forms of dyspepsia, can be even more easily sub- stantiated than any such gradual and ultimate change x 4 312 VEGETABLE FOOD. of general diathesis. Economically, again, it may be doubted whether the substances removed from corn in the shape of bran, pollard, &c, find a sale at prices equalling those at which the principles of Physiology, and the experience of most countries in Europe but our own, would agree in appraising them for human food; prices which ought to be scarcely less than those of that poorer (though whiter) flour which their subtraction has left. To the teachings of real experience on a point of this kind we ought undoubtedly to defer. But such experience, it may be presumed, should sum up the evidence on both sides of the question ; and, at any rate, ought not to ignore facts arrived at by Science in its zeal to record vague but popular impressions. And, if only "lihevare animam rneam" by the utterance of convictions formed in such scenes of suffering among the working classes as it is equally impossible to depict or to forget, — suffering often traceable to errors of diet, as its chief, or even sole, cause, — I must express a deliberate opinion that bread, " the staff of life," less deserves this title in England than in many other countries of Europe. The white bread of the huckster's shop is fast ousting the brown bread which the cottager formerly baked at home. Impoverished : adulterated ; injurious by its very monotony ; and certainly not yet supplemented (as it ought to be to render this de- terioration unimportant) by a sufficient allowance of meat ; — the bread to which the present generation of English artisans and labourers look for the munition of life is far inferior to that formerly prevalent in this country, as well as to that still common among the peasantry of France THE CHEAPEST BEEAD. 313 and Grermany. If dietetic considerations have any value ; if this subject of food be not the one subject on which observation and reflection disqualify for all deliberate opinion; the bread ordinarily in use in our country is a grievous national error ; which, sooner or later, may inflict on our national strength injuries even greater than any which are now attributable to it. A good, pure, brownish bread of simple wheat-meal, with even an ad- mixture of a fourth or a fifth of rye, would, for equal money value, give the labouring population a food in- comparably more abundant and nutritious than that which they now make use of as fine white bread. And in no way could the dyspeptic affluent set their poorer neighbours a better dietetic example than by adopting, were it at some little pains, a bread which might sometimes cure their own ailments by its mechanical quality ; as well as prevent disease and deformity among the lower classes by its nu- tritive value. The unfermented preparations of the various flours in the shape of biscuits, cakes, damper, &c, deserve no special notice. The closeness of their physical texture of course opposes their rapid and complete digestion. On the other hand, this very circumstance, and the smaller amount of watery moisture they contain, renders them much less susceptible of decay. The intensity and duration of the heat by which they are baked affects, both their moisture, and the condition of their starchy ingredients. From what has already been said, it is evident that many of the above grains would themselves, — suppo- sing the obstacles offered by their structure removed by 314 VEGETABLE FOOD. proper cookery — form a more economical and better food than most of the ordinary preparations of their meal. In the case of Kice, this is well known; the cleaned seeds, only prepared by soaking and boiling, forming the staple food of a large section of the human race. The other grains, however, seem yearly to be declining in repute as food of this kind. Hominy, furmety, groats, pearl-barley, are, indeed, still employed as a means of varying the diet of affluence. But, with the exception of the first, still valued aright by our American kinsmen, their more important office of forming an occasional or frequent substitute for bread in the meals of the labourer, is daily falling into greater desuetude. The various leguminous seeds constitute what is, both chemically and dietetically, a distinct group of vegetable foods. The term "pulse" (quasi pulled) formerly applied to them is now replaced by that of the above botanical genus, which connotes the same peculiarity of their har- vesting (legiint, legumen, gathering, gatherer) ; itself, in the case of some of them, now rendered obsolete by improved agriculture. If Cereal grains may be compared to milk, these seeds may be likened to cheese. For they contain a quantity of the protein-compounds which may be estimated as form- ing, on an average, nearly 30 per cent, of their weight : or half as much again as that present in the Cercalia. The quantity of their starchy constituent is, however, much less : being barely 40 per cent. They contain a some- what larger quantity of gum. They have also a larger (3i ) P er centage of saline ash ; the several ingredients LEGUMES. 315 of which, though almost identical with those of the Cerealia, approach each other much more nearly in quantity. From the few analyses hitherto made, it would appear that the quantity of alkaline bases is very large ; but that potash predominates over soda, and lime nearly equals magnesia. And though the phosphoric is still the predominant acid (about -f-ths of the 40 per cent, which the inorganic acids form of the whole ash), sulphuric and hydrochloric acids are also combined with the above bases : — the latter chiefly with soda. Their watery moisture may be estimated at about 15 per cent., being that loss of weight which they undergo by a thorough drying. The value of these vegetables as food w 7 ill of course depend on the preparation to which they have been sub- jected before being eaten. When ripe and dried, their small proportion of water, and their great density, as well as the little surface they expose, together render them almost impregnable to the attacks of the various digestive agents. And even after tolerable mastication, their larger fragments often pass with little change throughout the whole length of the human intestinal canal. But after careful boiling — which bursts their starch granules ; dissolves their gum ; and swells, softens, or ul- timately breaks up, their various insoluble tissues — they assume the proper digestive rank suggested for them by their composition. So prepared for eating, their large proteinous constituent renders them a most efficacious azotized food. The modified form in which it is present is, perhaps, not without some further import. The greater 316 VEGETABLE FOOD. part of it is a substance which Braconnot has termed Legnmin; and which, whatever its exact relation to glutin, may be regarded as having a solubility such as renders it analogous to ordinary casein. Adding to these consider- ations their large quantity of starch ; and their compara- tively uniform admixture of the very salts (save chloride of sodium) most important to Nutrition ; it becomes evi- dent that they have a completeness for dietetic purposes which even wheat can hardly be said to possess ; and which warrants the supposition that, if suitably prepared, some of these legumes might form a food sufficient for the maintenance of health. Experience abundantly confirms this vegetarian view ; and suggests a doubt, whether the Bible narrative which records the vigorous health of the Hebrew captives * under the use of this food, was intended to imply any miraculous interference with the laws of Nature. All the world over, the use of these leguminous seeds has in general been adopted as widely as climate, soil, and the art of agriculture would together allow. The Pea, the Bean, the Lentil, in all their natural and artificial varieties, have spread wher- ever civilization has extended ; and seem to be largely made use of in many parts of Asia and Africa, otherwise little addicted to agriculture, or to a careful choice of food. Here again, however, England seems to be receding, rather than advancing in knowledge. Whether this re- gress must be ascribed to the increasing division of labour ; or to the subtraction of women from home life to factory and field work; or to the aggregation of population in * Daniel, chap. i. y. 12. POTATOES. 317 towns ; or to the gradual conversion of agriculture into a trade governed by demands from without, rather than a production of food in consonance with the instincts of the healthiest and most natural groups of the community — the cottier, and the small farmer — it is beyond the province of Physiology to inquire. But that the use of Legu- minous seeds as food, has greatly decreased even in the last thirty years, no one intimately acquainted with the habits of our working classes can affect to doubt. Pease porridge, pease-pudding, and a variety of other dishes of this kind, formerly so commonly eaten as to be hawked about the streets of most large towns, are in many places now almost unknown ; or linger only at the tables of the affluent to add, in the form of pease-soup, precisely that ingredient of diet which they are otherwise pretty sure to take in excess. Eeflections like these make it little worth while to search out the details of various other articles of food, such as Acorns, Nuts, Chestnuts, and the like; which, in this country, nobody eats as a staple of food. Their pro- teinous ingredient is such that they might be made both wholesome and palatable by careful cooking. Dietetically, they would then rank between Pulse and the Potato. In Nuts, there is also much fatty matter. The Potato, the starchy tuber of a plant belonging to the poisonous genus of the Solanece, is an article of vege- table food, which, in composition and properties, offers a remarkable contrast to the preceding group. The anatomy of the tuber shows it to consist of an ex- ternal epidermoid membrane, enclosing a very moist but 318 VEGETABLE FOOD. solid mass ; which is distinguishable under the microscope as a series of largish cells, polyhedral from close packing, and enclosing a copious acid juice of a limpid consistence, with a number of fine starch granules. This acidity is due to malic acid ; as well as to a variable, but smaller, quantity of free phosphoric acid. The composition of the Potato-tuber may be summed up, from the numerous (nearly 150) and careful analyses of Koerte, Siemens, Horsford and Krocker, Einhof, Lam- padius, Michaelis, and others, as 75 per cent, of water, with 25 of dry solids. Of the latter, about \5\ parts are starch, and 1^ soluble albumen, with which is united a small (less than \ per cent.) quantity of a secondary azotized compound termed asparagin. About 7 per cent, of cel- lulose (doubtless by no means free from starch), and 1 per cent, of ash, complete the whole 100 parts: and form an estimate, chiefly defective in the fact of its not esti- mating the acids just alluded to, which often seem to attain a proportion of 3 or 4 per cent. The salts of the Potato are remarkable in many re- spects. The fixed constituents found in its ash have been analysed by A. Vogel, Boussingault, and Way ; whose re- sults, however, scarcely agree with themselves, or with the organic ingredients already noted. Thus A. Vogel found | of the total ash to consist of carbonates ; of which by far the larger proportion (55 per cent.) was composed of the carbonates of soda and potash, in nearly equal pro- portions (34 of soda to 21 of potash). Doubtless much of these carbonates had been united with organic acids in the fresh tuber. Boussingault and Way, however, POLITICAL INFLUENCES OP THE POTATO. 319 agree in representing the soda as a mere trace ; and the potash alone as about 54 per cent, of the ash. The phos- phoric and sulphuric acids — about 12 and 7 per cent, of the ash respectively — seem to be chiefly combined with the latter alkali ; though a certain quantity of magnesia (6 to 14 per cent.) and a much smaller (about J) proportion of lime, have been found as bases. Finally, chlorides seem also to exist in very different proportions in different specimens : being almost absent ; or present chiefly as chloride of potassium ; or, lastly, being represented by free hydrochloric acid, which is probably produced, by displace- ment from some chloride, during the lactic fermentation of part of the starch of the tuber. Perhaps there is no article of food which more strongly claims the attention of the educated public, than does the Potato. Certainly there is none which better illustrates the intimate causal relation between the food and the habits, the physical and the moral state, of nations. In- troduced into Europe from America, by Hawkins, 250 years ago, it is only during the last 100 years that its cultivation has assumed such enormous dimensions, as to subvert the dietetic habits of whole nations, and to accomplish a silent revolution, from which only the last few years have promised any efficient reaction. Through- out many parts of Europe, the poorer classes have now, for years past, been relying for their nutrition chiefly on the Potato. And though the sturdy English sagacity of Cobbett long ago pointed out the danger of this procedure, as well as the insufficiency of this vegetable to replace those more nourishing articles of food, which, in the shape of 320 VEGETABLE FOOD. corn, &c, had been vouched by the experience of thou- sands of years ; though, indeed, both here and abroad, his presagings could be traced in course of fulfilment ; it was not until the terrible climax of the Irish famine, that the British nation became aroused to the recognition of those more casual, but not less dangerous, effects which spring from trusting to the Potato as a staple of food. The immediate advantages of its cultivation were ob- vious and undeniable. With little toil or trouble, the Potato extracted from the ground an amount of nourish- ment far surpassing that which could be obtained by the growth of wheat or any other grain. Frerichs estimates that the same surface of land would yield in Potatoes twice as much protein, and four times as much starch and mineral ingredients, as if sown with Wheat. Hence the cultivation of the Potato over large tracts of country first gave a cheap and plentiful food ; and then permitted an increase of population, up to the full limits of that ex- tended capacity of nourishment thus acquired by a given space. This was especially the case wherever the tenure of land implied, either its subdivision among a number of small proprietors, or (worse still) its subletting through various agents from the landlord the cottier tenant at a rack-rent. A simple process of digging, planting, waiting, and eating, replaced the perpetual foresight and labour of legitimate husbandry. And its natural results gradually attained their climax in Ireland ; where might be seen a population, distinguished, abroad, for undaunted industry and self-denial ; but, at home, bereft of the best occupation of life, and the strongest incentives to exertion ; and living FAULTS OF THE POTATO. 321 in numbers unduly multiplied, on a plant not only pre- carious, but (as we can now see after the event) sure to be ultimately weakened or destroyed by the exhaustion of some of its ingredients from a continually impoverished soil. The above sketch of the composition of this vegetable sufficiently entitles the physiologist to range himself with the political economist, in determined opposition to the use of this vegetable by any population as their principal article of food. We may dismiss from further notice all consideration of that social and moral degradation which, ever since its introduction, have been steadily following such an undue use of the Potato as the staple aliment in various parts of Europe. We may even set aside those fearful outbreaks of pestilence in Ireland which, though produced by the quantitative failure of one crop, must surely have been in some degree fostered by a peculiar state of the constitution — by a mental and physical de- generation — itself probably founded, in part, on the qua- litative deficiencies of the previous food. Our objections to the Potato find a better excuse in such a composition as the above. Eough as is the above estimate, it neverthe- less claims to be based upon analyses of unusual number and accuracy. It shows that the food to which it refers is wanting in some of the most important saline constituents of the body ; — such as the phosphates *, sulphates, and chlorides, which are hourly leaving the organism in com- * It may be estimated that a given weight of potatoes contains scarcely one-tenth of the phosphate of magnesia present in the same quantity of wheat. 322 VEGETABLE FOOD. paratively large quantity. And that, in addition to this grave fault, it contains so small a proportion of protein, that we may calculate about thirteen pounds of Potatoes as the quantity which a man ought daily to consume, in order to replace the waste of his body by a sufficient sup- ply of histogenetic constituents in his food. ■ At least this would be the amount of Potatoes corresponding to the protein which experience shows to be enough, and not too much, for the daily ration of a soldier ; that is, for the food of an adult male, in good health, and habituated to moderate, but not excessive, bodily labour. Lastly, it- need hardly be added, that the form and arrangement of the protein contained in the Potato are such as would scarcely ever allow it to be as well digested as the protein contained in the bread and meat of the soldier's ration. Hence its less suitable quality would require to be com- pensated by a still further increase of quantity. While it is altogether devoid of fat. But the mixture of the Potato with other alimentary substances, and especially with meat or milk, removes all these objections, and restores it to its proper rank in the scale of diet. Indeed, just as, in theory, the addition of protein, fat, and chloride of sodium, would give the above analysis exactly that complement necessary to the com- position of a typical food ; so, in practice, numberless in- stances might be adduced to prove the experimental value of various admixtures of this kind, in exact proportion to the accuracy with which they correspond to such a com- plement. Potatoes and milk ; Potatoes and fish : Potatoes and bacon ; Potatoes and red-herrings, or even salt-cod or SUCCULENT EOOTS. 323 ling; nay, even Potatoes and cabbage: — these, and a variety of other dishes, equally vulgar, and equally valuable, cor- rect the worst dietetic error of the " Potato-eater ; " and indeed disqualify him for this title, save in some such re- stricted sense as " Vegetarian " applies to an eater of eggs, cheese, and milk ; or (C Teetotaller " to a person who uses alcohol, both often and willingly, as a medicine. The defects of the Potato thus corrected, its large starchy ingredient is of extreme value ; the more so, that the diffusion and admixture of its starch remarkably favour due metamorphosis and absorption. And its saline constituents, its potash, and its organic acids, admirably explain that use of this vegetable as an anti-scorbutic, which experience has long proved to be one of its most valuable qualities. Succulent Roots. — Another class of vegetable foods may be found in the juicy roots * represented by the Turnip, Carrot, Parsnip, Beet, Mangold, &c. Although the exact composition of each of the above vegetables is, in some respects, unlike that of all the others, still they may be tolerably comprehended in a common description* Their large watery ingredient of 80 to 90 per cent, is of course equivalent to a small solid residue, and nutritive power. Their protein, chiefly in the form of soluble vegetable albumen, ranges from 1 to 3 per cent. ; the former proportion being nearer the average, the latter rarely attained, save in the case of the red Beet. Their sugar is in large quantity; ranging, it would seem, in * Botanically, of course, these fleshy succulent enlargements of the underground stem are not roots, though usually so termed. Y 2 324 VEGETABLE FOOD. these roots generally, from 5 to 15 per cent, of the fresh vegetable, or 90 to 95 per cent, of the solid residue of the juice; a proportion often exceeded in favourable spe- cimens of the Beet from which sugar is manufactured. A variable (and hitherto undetermined) quantity of pectin (C 12 H 16 O 10 ), with dextrin, gum, and a little starch ; a small proportion ( 15 1 QQ th) of fatty matter ; and compounds such as inulin (C 12 H 10 O 10 ), and carotin (10C 5 H 4 ) ; make up the remaining organic constituents : which, on the whole, must be regarded as collective^ rich in nutriment. The ash, which forms about 1^ to H per cent, of the fresh substance, appears from the analyses of Boussingault to differ from that of the Potato in some important par- ticulars. The total amount of bases differs little in the two ; but, in addition to the potash largely present in both, and a considerable amount of magnesia, these pectinous roots contain soda and lime in much greater proportions than does the Potato. Of the inorganic acids, the phosphoric is greatly below its proportion in the Potato. The quan- tities of the organic acids are scarcelv determined : but the malic and citric acids, which predominate among them, seem in the fresh vegetable to be combined chiefly with potash and lime. Fruits. — The fruits most cultivated in this climate — Apples, Pears, Plums, Peaches, Apricots, Cherries, Goose- berries, Currants, &c. — have in many respects a composi- tion analogous to the preceding. A watery ingredient ranging from 70 to 80 per cent. : from 2 to 6 of gum and pectin; 10 to 25 of sugar: a variable but small propor- tion of protein (averaging J per cent.?): and about H I VALUE OF EOOTS AXD FEUITS. 325 per cent, of malic ot other organic acid ; — might be regarded as their mean composition. Of course the insoluble, fibrous, or cellular substance of all these fruits, and the woody masses of some of them, add other in- gredients; which, in any quantity, further detract from their nutritious qualities* Looking at the mere composition of both these groups of vegetable substances, it cannot be doubted that their nutritive value is very considerable. But, even allowing for the influence of habit, and for the probable, though vague, transmission of digestive peculiarities by hereditary de- scent, experience seems to indicate that they are unfit to form the staple of human food. Their chemistry per- haps in some degree explains this fact. Deficient as most of them are in the proteinous principle, they are, so far, unsuited for the maintenance of Nutrition, without the admixture of other and more azotised substances. In the case of some of them, a process of drying and rough powdering, which produces a kind of coarse meal, obviates some of the effects of the large watery element that dilutes their more nourishing ingredients. Their de- ficiency in fatty matter, and in phosphates, as well as in other salts, constitutes another explanation of their insufficiency as food. Nor must it be forgotten, that the scanty digestibility of many of these vegetables reduces their nutritive value far below what a mere analysis might suggest ; large proportions of their substance pass- ing through the digestive tube with comparatively little change. Hence, while their composition might perhaps indicate that nothing save a warm climate, and a scanty T 3 326 VEGETABLE FOOD. daily waste, would allow their large sugary and gummy ingredients, and small proteinous constituents, to sustain Nutrition ; the organs of Digestion themselves enhance the difficulties which the concurrence of the above circum- stances with those relating to the growth or culture of these fruits and roots in sufficient quantity would together imply. In short, they are, relatively to the human organs, too indigestible for a staple food : indigestible, probably, both in the sense that they do not evoke digestive juices of proper quantity and quality ; and that they cannot yield up sufficient of their constituents in their transit through the human alimentary canal. And even when improved in these respects by proper cookery, they still remain valuable rather as supplements or variations of the habitual food, than as substitutes for such articles as meat, bread, or even Potatoes. The precise manner in which their pectinous constituent is applied to the uses of the organism can scarcely be at present explained. But its composition is so far akin to that of the gum and sugar by which it is accompanied, that we may fairly presume it to subserve purposes analo- I gous to those accomplished by these hydrates of carbon, among which substances it may indeed be almost classed. And the direct nutritive usefulness thus claimed for pectin can hardly be denied to those organic acids associated with it : — acids which seem not only to disappear in the blood, where they probably undergo an oxidation that ultimately converts them into carbonic acid and water, but also to subserve still more definitely to the 'regeneration and in- terchange of the various tissues. GREEN HERBS. 327 Indeed, with respect to both the salts and acids of these vegetables, it is important to recollect that there are many phenomena of health, as well as of disease, which indicate, far more decisively than can be explained by our present knowledge of Physiological Chemistry, how great is the value of such ingredients to the organism in general. Without at all denying that albumen, starch, gum, may possess very dissimilar nutritive characters and values in the various forms in which they are afforded by different kinds of food, — characters such as our chemistry can scarcely hope to appreciate, — we may at least find more striking distinctions, between many of these vegetables, in the quantity and quality of the ingredients associated with these alimentary constituents. And as the incontrollable longing of Man after variety of diet is especially noticed in the cultivation and consumption of fruits and vegetables, and his sense of taste is especially distinguished for the delicacy with which he distinguishes — shall we say the catholicity with which he appreciates? — the innumerable shades of flavours offered by these various kinds of food, it seems evident that health and instinct here go hand in hand. Beyond a certain limit, indeed, the disregard of this instinct rarely fails to attract or enforce disease ; which (as in the case of the scurvy still occasionally met with in our large towns, and formerly raging with great danger and severity during the winter scarcity of vegetables and fruits,) may well serve to advise us that, within certain limits, this instinctive taste is based on a bodily want ; the satisfying of which is not a concession to luxury, but a payment of the just claims of health. Y 4 328 VEGETABLE FOOD. Green herbs. — The shoots, leaves, &c, of various plants, may be regarded as a class of vegetable food distinct from the preceding. In composition, however, many of them closely approach the mean estimate above given for the succulent roots. But it is hardly necessary to say how great are the variations in their ingredients. For a con- trast of even the commoner esculent vegetables of this kind would abundantly suggest their great diversity from each other, in respect to chemical, as well as physical, pro- perties. For example, not only do the various kinds of Cabbage, the Lettuce, Asparagus, Spinach, Celery, and numberless other vegetables used as food, differ materially from each other in both these respects ; but, as every house- keeper knows, offer considerable differences of value in different specimens, according to their age, culture, and preparation. Hence the following rules may sufficiently modify the preceding statement as to their general analysis, and the presumption it affords us respecting their nutritive value. Starch especially abounds in the young plant ; in which it- is often associated with albuminous substances that occupy the various cells of the vegetable organism, and from which the comparatively soft texture of these and all other parts permits its easy extraction by the digestive function. Conversely, the process of vegetable development, even if it should not exhaust the stores of these nutrient materials de- posited for the use of the young plant, rarely fails to render them far less useful ; by enclosing them within cavities of tough cellulose, or of hard woody materials, such as defy any ordinary process of solution in the human alimentary ESCULENT FUNGUSES. 329 canal. Sugar rarely abounds in these plants. Grum is much more plentiful. Salts are especially abundant ; po- tash generally exceeding soda ; and even the chloride of sodium being occasionally plentiful (in spinach, according to Saalmueller, 13 per cent.). It is chiefly in the older plant, however, that any large quantity of saline ingredients is present ; and their increase is often accompanied with what is almost a proportional decrease of water. Lastly, the more specific properties of the particular vegetable are generally associated, not only with its growth, but especially with its development % of green tissues under the action of light: — giving it, for ex- ample, the stimulant and sedative properties attributed to the Mustard and Lettuce respectively; or a rank, and even poisonous quality, such as proper cookery alone can banish or reduce to safe limits. Other vegetables. — Without enlarging the narrow limits laid down for these sketches of food, two or three groups of vegetable aliments may be alluded to, as falling without the boundaries of the preceding classes. The dried fruits, exemplified by the Eaisin, Prune, Date, Fig, are chiefly remarkable for the large quantity of sugar which they possess ; as well as for that considerable proportion of pro- tein which the loss of their water enables the two latter especially to show. The Melon tribe, besides a large (95 to 97) watery constituent, and the poverty of solids this circumstance implies, have little which is chemically re- markable. The Fungi, in which the watery ingredient is reduced to one-tenth, are rich in albumen ; and also contain a large proportion of sugar, as well as of dextrin and 330 VEGETABLE FOOD. fatty matters. Their nutritive qualities, depending partly on these four first constituents, are, however, often alloyed by the poisonous properties of the organic acids which also enter into their composition. The proper selection of species is of course the most obvious precaution against this risk. But the younger funguses, and those which grow in situations freely exposed to sun and air, are far less dangerous ; so much so, as to be often harmless even in doubtful species. Lastly, in some of the Algceand Mosses, starch, sugar, and dextrin or pectin, are present in con- siderable quantity. In the dried Iceland-moss, for in- stance, as much as 40 to 70 per cent, of a starchy ingre- dient has been found (Berzelius and Schneidermann) : in the Carrageen or Irish-moss, about as much pectin. Both yield to boiling water a large percentage of these nutri- tious constituents ; the decoction, which cools down to a jelly, being so nourishing and so easily digestible, as to be comparable to a vegetable soup. 331 CHAP. IX. CONDIMENTS. Condiments, their Character. — Their Kelations to Food and Medicine. — Salt as illustrating these Eelations. — Its Uses. — Eelation of Salt Meat to Scurvy. — Effects of excessive Ingestion of Salt. — Exceptions to its Use ; in Man, in Animals. — Acrid or Stimulant Condiments. — Their Uses with reference to Appetite, Circulation, Secretion. — Spices. — Their Use as Medicaments. — Complementary Nature of some Condiments. — Alliaceous Condiments. — Their Varieties. — Active Principles of Vegetable Condiments. — Oils. — Alkaloids. — Condiments as Ingredients of Sauces or Complementary Foods. The distinction, among the various substances ordinarily used as food, of a class of ingredients called condiments — which give savour rather than nourishment, and are thus only useful when blended and united (as their ety- mology, con, duo, implies) with other substances more strictly assimilable or alimentary — is too old * and too valid to question, too well-known and understood to require much illustration. Nevertheless, easy as it is to recognise the class of con- diments by its vague outlines as thus indicated, it is quite impossible to define its exact limits ; or to draw the lines which separate flavour from food, and food from * Thus Sir Thomas Brown (Vulgar Errours, b. iii. c. 22) says, "For many things are swallowed by animals, rather for condiment, gust, or medicament, than any substantial nutriment." 332 CONDIMENTS. medicine. Indeed, to this fault, more or less incidental to all classifications of natural objects, the kinship of which involves kindred properties, we may add another, more inherent to the above distinction. Flavour, in general, increases not only the pleasure, but the profit of eating ; and is thus, indirectly, tantamount to an increase of ali- ment. Nay, more, the choice between foods almost identical in the broader features of their chemical com- position is often determined by characters such as are chiefly condimentary ; so that, for example, the preference of one variety of butter or oil to another, or even of butter to other fats, may be regarded, under this aspect, as the choice of a condimented, rather than of a mono- tonous, hydro-carbon. Lastly, a very large proportion of the most valuable drugs or medicaments of modern civili- sation resemble the simples or herbs of the savage, in the circumstance of their being, in some sense, substitutes fot the collateral ingredients of proper food ; or casual, rather than habitual, condiments. The use of Scurvy-grass by Arctic voyagers ; the spring course of cooling herbs taken by our ancestors, after their long winter course of salted meats ; the Lemon-juice required to prevent or cure scurvy among mariners, whose food also shows an excess of salt and a deficiency of vegetables ; the salines, the iron, the Taraxa- cum, used by the dyspeptic or chlorotic ; perhaps even the cod-liver oil consumed by the strumous — are all ex- amples of medicaments, the unquestionable benefits of which render them tantamount, in some respects to con- diments, in others to food. And, therapeutically as well as dietetically, it is important to bear this in mind : if only SALT. 333 as an additional safe-guard against the error, expressed by- Sir Walter Scott's blacksmith turned physician, but per- haps sometimes implied by more legitimate authorities — that the " twa simples, laudamy and calamy " may be ranked with those herbs which often minister to the healing of our diseases by repairing the defects, or re- moving the excesses, of our habitual food. Salt, or chloride of sodium, the first of all condiments, will best illustrate and confirm this view. A large constituent of the blood and all the tissues ; a source of the gastric acid (compare pp. 119, 120); a more than incidental ingre- dient of all the secretions ; and therefore, a necessary part of the aliment ; it is strictly a food of the highest value. On the other hand, though it is casually present in many articles of food, the fact that it is generally absent in that quantity which is really requisite to meet its expenditure l}y the organism, and that it therefore requires to be added to (or rather blended with) the alimentary substances com- monly made use of, renders it practially mo^t important to regard it as a condiment, however indispensable an one. Lastly, the results of its habitual deficiency — as shown, in Man, by the access of dyspepsia or other diseases, easily remedied by its use ; or, among animals, by that extraor- dinary craving for it which often compels a timid Deer to risk its life, and reverse its habits, by going hundreds of miles through danger and difficulty to a " salt-lick " — prove it to be just as truly a medicament: nay, more, a drug which seems to be capable of being suddenly accu- mulated in the system ; and of being thereafter so slowly 334 CONDIMENTS. and scantily expended as to meet the unfavourable circum- stances of its large and intermittent supply. Perhaps some of the details of its action require a fuller statement. The deprival of all salt was an ancient Dutch punishment for criminals ; and is said to have been generally followed by disease, decay, and even a maggoty state, of the tissues. The bread and salt of Arab hospi- tality ; the salt which the Hindoo affects to regard as an obligation of faithful service ; the forms of excommuni- cation of the Eomish church : — all attest the result of experience as to its indispensable character. At the same time, this very character prevents our more accurate know- ledge of the results of its withdrawal ; by making such a deficiency an element of the severest famine, rather than an example of the mere absence of salt from the food. And as it is used by many persons in great excess of what is necessary, the health certainly often observed in th£ case of persons who have an aversion to it as a condiment in all but the smallest quantities, is quite explicable as a difference of degree and not of kind : the moderate amount of salt really wanted by the system being fur- nished by the food or its adjuncts. In domestic animals, its copious, as distinguished from its necessary, use seems greatly to facilitate the process of fattening. But the process of artificial fattening, if pro- perly pursued, may be regarded as only an expression of rapid and exalted Nutrition in general. And the eager- ness with which Cows and Horses lick salt, may fairly be taken as an indication that this craving for it corresponds to a deficiency of it in their ordinary food. Guided by SALTED MEAT. 335 such instinct, the use of salt by brutes * seems never to amount to any real excess. The process of salting meat, however, impregnates it with so large and undue an amount of salt, as to cause persons who feed on such meat to exemplify the results of excess in reference to this condiment. Doubtless, scurvy is often privative ; in the sense that a mere absence of vege- table food will produce it in many constitutions, in spite of the copious ingestion of the fresh meat of tame cattle. Frequently, indeed, are such cases seen in medical prac- tice. Barely, too, analogous phenomena have been wit- nessed on a large scale.* * But it cannot be questioned that the effect of salt meat is by no means exclusively attributable to any coincident absence of vegetable food, or even to that partial extraction of its dissolved and watery constituents which this mode of preparation in- volves (chap. xii). The excess of salt injures the meat in a more positive way ; and not only, as in artificial digestion (p. 124), impairs the powers of that gastric juice by which it has to be taken up ; but seems to aid in bringing about that faulty and diffluent state of the blood, and of the tissues generally, which the phenomena collectively known as " scurvy " seem to exemplify. It cannot, however, be doubted that a large excess of salt may be constantly taken into the human organism, from the food, without any detriment to what is apparently robust health. Of such an excess of salt, a large quantity makes but a very brief stay in the blood, being at once * As in an English regiment decimated by scorbutic disease under a fresh meat diet in South Africa many years ago. 336 CONDIMENTS. carried out by the stream of urine. Indeed^ the excess itself seems easily to pass out by all channels : not only, for instance, by the healthy excretions, but even by the effusions of disease ; in which its proportion seems often increased by a reabsorption of the watery and other in- gredients of the original exsudation. In this way the fluid of ascites is often highly salted ; or the sputum of pneumonia exhibits a quantity of this chloride, which goes far to explain its cotemporaneous deficiency from what is ordinarily its chief channel of removal from the body : to wit, the urine. A proportion of such an habitual excess is, however, left in the body ; most of the tissues of which probably become impregnated with a quantity of salt far larger than would suffice for the most vigorous health.* There are many apparent exceptions to the rule of the indispensableness of salt. Numbers of wild animals seem to have little access to any quantity of this substance. And many wild or semi-civilised tribes of Mankind are said to abstain from all use of it as a condiment, in which form its taste causes them unmistakable disgust. But it is doubtful whether such instances are really anomalies. For it is certain that many vegetables and spring waters con- * In a recent narrative of a protracted residence in Polynesia, the humorous suggestion of Sydney Smith, that the hospitality of a native chief always kept "a cold missionary on the sideboard," is robbed of half its terrors by the statement, that the cannibals of this region greatly object to the distasteful, if not unwholesome, saltness of their European visitors when cooked as food ; in contrast with whom their own countrymen have quite a sweet and agreeable flavour. (Nineteen Years in Polynesia. By the Rev. G-. Turner. Snow, London: I860.) Conversely, the cannibals of Western Africa find (according to Hutchinson) a relishing saline flavour in the inhabitants of the sea-coast, by comparison with those living inland. HEATING CONDIMENTS. 337 tain a considerable proportion of salt ; and probable, that the proportion thus received by Herbivorous animals would communicate to their flesh enough to render this, in its turn, a tolerable supply to the Carnivorous animals or tribes by whom it is eaten. And the moderate quan- tity requisite, if tenaciously retained (combined ?) in the organism, may render unimportant all further addition to the above supply. In consonance with such an ex- planation it will be generally found that it is in the inexhausted and equable composition of a virgin or uncul- tivated soil; in the wild cattle who feed on its grasses, rich in minerals (and especially in chlorides) ; and in the active savage or semi-savage who feeds on such an animal food ; that we find the chief (if not the only) instances of a complete and habitual neglect of this condiment. Con- versely, the food most deficient in this salt is that which notoriously most requires it ; so that, for example, the dyspepsia caused by its deficiency in a predominantly starchy food, is at once relieved by its medicinal use.* Heating condiments. — A variety of acrid and stimulat- ing substances — instanced by the peppers, mustard, horse- radish, &c. — constitute the next group of condiments. Concerning these, some would perhaps think the ques- tion " Are they of any service ? " a necessary preliminary to the question " How are they of use ? " * In Dr. Livingstone's Travels lately published, the remarkable fidelity of his description of the effects of such a food permitted me to recognise a variety of dyspepsia which I had long distinguished, both in its nature and causes, from other forms of this complaint. (See the author's work " On Diseases of the Stomach," p. 366.) Z 338 CONDIMENTS. It would be easy to make a fair show of reasoning against their general value ; to insist, for instance, that they have been, in all ages and countries, a means for tickling the luxurious palate by an artificial stimulus, and for provoking a fictitious appetite beyond that which nature affords. No doubt, too, the mass of civilized Mankind would do very well without them : the affluent dyspeptic gaining by their loss; and the poor (like the discreet Mr. Weller) caring very little for horse-radish when they could get beef. But, on the other hand, experience shows that they are too generally adopted to permit us to suppose them quite valueless. The very large quantities habitually made use of in some countries — India. Abyssinia, Mexico, and South America generally — may be referred, partly to the exaggeration which custom can bring about in all social observances, partly to that decrease of sensibility which the digestive organs acquire under the influence of habit. But taken in moderation, these condiment- seem useful by increasing the afflux of blood to the various secreting structures, and thus provoking a larger supply of solvent iuices. And as it is certainly in tropical (or at any rate, hot) countries, that they are most used and most useful, they may be conjectured to help the system, as well as the digestive organs, to overcome the languor and debility which external heat tends to produce : as well as — inci- dentally or specifically — to contend against the direct unwholesomeness of some of these warm climates. Whether any of these condiments have the power of act- ing directly upon secretion — so as to provoke (for example) THEIR INFLUENCE ON SECRETION. 339 the formation and effusion of an increased quantity of gastric juice — is a question impossible to decide, in our existing ignorance of the exact mechanism of the secretory- process. But a variety of considerations appear to militate against their having any such virtue ; and reduce their probable influence upon the digestive juices to that of aiding the determination of blood towards the mucous surfaces which they stimulate; and of thus furthering the process of secretion, in a way which is subordinate rather than essential, and which increases the watery and saline ingredients of. the particular secretion, rather than its more energetic and specific organic constituent. The obvious value of such a collateral aid seems quite to ex- plain the teachings of experience as to these condiments. While not merely the relation of that irritation w T hich they produce to the inflammatory process, but especially the history of experimental research on these various digestive juices — the obtaining of which has often been sought for by the aid of such stimulants — disclaims for these acrid spices any larger or truer influence on secretion. But besides the above properties, it is evident this class of condiments possesses others ; by virtue of which many of its members must be regarded as not only complementary to deficiencies in the composition of food, but as exercising on the whole organism an influence of a much more recon- dite kind. These properties, as already noticed, may fairly be termed " medicinal," if we look only to their effects, as verified by experience, in preventing or curing disease. And in any inquiry into their medicinal virtues, there are obvious grounds for surmising an action which, in the case of some, Z 2 340 COXBIMEXTS. is mainly local, on the alimentary canal ; in others, is pre- dominantly on the system at large, presumably through the mediation of the nervous system. So that, for ex- ample, many of the spices may be vaguely (but not inac- curately) looked upon as related to such stimulant - mustard on the one hand ; and to the powerful cerebro- spinants of tea, coffee, and even alcohol, on the other : and as medicinal in both aspects. It is therefore no wonder that they have been, from earliest ages, some of the most useful of our drugs : — just as, in the bitter herbs used by some nations in cookery, or the salicine from willow-bark (Ruempfcheri) added to some fish in Ger- many, we can see how, if it were the fashion to take quinine in such a manner, this admirable drug would fulfil many of the purposes of a condiment. Perhaps the strangest instance of the partly comple- mentary office of some condiments may be found in the mechanical (as distinguished from the qualitati they are rarely made to fulfil. The bee-hunter of Ceylon mixes with honey a comparatively innutritious mass of soft tindery wood, which gives it the necessary bulk and con- sistence. Even here, however, the condiment — for such the substance really is — must probably be looked upon as in some degree qualitative : containing, like the bark sometimes added to bread in Norway, a scanty supply of nutriment. Alliaceous condiments constitute another large and im- portant group, instanced by the Onion and its congeners. Botanically, the group is imperfect : or rather should be enlarged so as to include various substances, possessing ALLIACEOUS CONDIMENTS. 341 very different degrees of what is, in all, substantially the same odour; from the mild Onion of warm climates, to the small and potent Onion of northern latitudes, the Leek, Eschalot, Garlic, and even the Asafoetida which is the de- light of Asiatic gourmets. Their rise in stimulating power, and in intensity of condimentary flavour, for the most part corresponds to their association with a decreasing amount of nutritious fluids and solids. The large sulphurous con- stituent which seems to be associated with this odour, is doubtless in part applied to the purposes of the organism. But it seems to be so largely in excess of any such use, that much of it escapes by the excretory channels of the skin and lungs : in the case of Asafoetida, literally tainting the air for some distance to leeward of its votary. Looking at these vegetable condiments as a class, it is obvious that, though their alimentary — in other words, assimilable — ingredients are subordinate to their stimu- lant or aromatic ones ; yet their valuable salts, and their often large proportion of organic substances or juices, render them strictly food ; especially in the sense of their complementing what experience and instinct show to be deficiencies in the food to which they are added. And in this respect it must be owned that the gradations from the least to the most nourishing members of the class are too slight to justify any exact line of demarcation. So that, for example, in passing from the large Spanish Onion, through Leeks, Garlic, Horse-radish, Cinnamon and its congeners, to the various Peppers, which attain a kind of climax of condimentary power in the Capsicums, it would be impossible to say where food ended, and con- z 3 342 COXDDIEXTS. diment began ; much more to deny, even to the most sti- mulating, all possibility of its adding some minute (and not uninfluential) ingredient to the organism. Subtracting, however, those alimentary ingredients more or less incidental to them all, or abstracting the stimu- lating ingredients to which they chiefly owe their condi- mentary virtues, would alike give us a group of bodies deserving some general notice. Of these bodies, some of the most important are a series of oils, possessing great acridity of taste, and an equally powerful odour. These oils are sometimes — as in the case of mustard — products rather than educts ; being formed by the reactions of various organic ingredients of the Mustard-seed under the influence of a kind of fermentation. Oftener, they are present as essential oils ; which are sometimes termed ethereal oils, although it is more than doubtful whether those elements of ether whicli are present can be regarded as combined with the other ingredients in any such form. In Mustard and Horse-radish, as well as in the Onion, Garlic, and Asafoetida, the large sulphurous constituent of the condiment is combined with its oil : which, in the case of Mustard, seems also to possess another remarkable or- ganic ingredient — cyanogen — united with it in the form of sulpho-cyanogen. Alkaloids are, on the whole, a far less frequent con- stituent of these condiments : being almost limited to the piperine of Pepper. Both oils and alkaloids seem to be given off by the skin, the lungs, and especially by the urine, with little change : a circumstance which certainly goes far to support the view, that as regards some of ACID CONDIMENTS. 3.43 these condiments, their local action on the. digestive canal, and their general effect on the nervous system after ab- sorption, constitute their whole value. In all of them, indeed, their contribution of assimilable material must be regarded as the smallest and most doubtful element of their usefulness. It may, however, be questioned whether any statistical view of condiments would not qualify such an opinion ; by showing that, in practice, condiments are generally used in combination with materials, the composition and other properties of which render them complementary foods. For all the milder condiments essentially claim this position. While the stronger are often used as the ingredients of sauces, in which they are not only diluted in intensity, but are supplemented by other flavorous and odorous sub- stances, the composition and uses of which for the most part approach those characteristic of the condimentary class. Acids, as condiments, are, if we except the oxalic acid scantily contained in some salads, almost restricted to the acetic, and to the citric of lemon-juice. Vinegar, if used in small quantities, appears to have little effect on the organism generally. But, like all the acids, it seems to promote digestion ; probably by its influence on the gastric secretion, the solvent properties of which it strengthens (p. 123) both in and out of the body. In large quantities it is diaphoretic ; a circumstance probably associated with its larger consumption in warm countries, as in Spain. Its prolonged and excessive use appears to lead to emaciation, and to other serious symptoms of impaired Nutrition* Z 4 344 TEA ASD COFFEE. CHAP. X. TEA AND COFFEE. Tea and Coffee. — Their Introduction into Europe. — Eesults of their general Use. — Their Contrast and Analogy; in Effects, in Composition. — Tea. — Its Source. — Its Varieties (Black and Green). — Coffee; its Source. — Composition of Tea, and of its Infusion. — Composition of raw Coffee. — Effect of Roasting. — Proximate Ingredients of its Decoction. — Nutritive Value r of Tea and Coffee. — Physiological Effects. — Their possible Relation. — Theory of the economizing Action of Tea and Coffee. — Re- searches of Boecker and others hereon. — Resemblances, and Cont: of their Action. — Objections to such Views in general ; to these Experi- ments in particular. — Cocoa and its Preparations. — Their Contrast with Tea and Coffee. — Their dietetic Value. Tea and coffee, two drinks gradually introduced into Europe about 200 years ago, and now in general use over the whole civilized world — the various nations of which they may almost be said to share as their respective votaries — occupy a position in the list of dietetic sub- stances altogether disproportionate to the scanty (and even doubtful) contribution which they bring to the organism, as a true or assimilable food. In that silent revolution of Diet w T hich they may claim to have effected, scarcely any large element of political or individual life seems altogether uninfluenced. Commercial intercourse, social habits, moral culture, mental development, and even bodily dis- eases and diatheses — in respect to all of which the present THEIR HISTORIC INFLUENCE. 345 epoch offers so remarkable a contrast to the sixteenth century — appear to owe no small share of this contrast to the various and important changes worked or permitted by tea and coffee in our food and drink generally. As more harmless luxuries, and less potent stimulants, than those alcoholic drinks which they have in great measure substituted and displaced, they have doubtless been of infinite service ; and have indirectly brought about a great diminution of the grosser intemperance prevalent when wine, ale, and " strong- waters " were used much as tea and coffee now are. Sometimes, it may fairly be presumed, directly stimulating the mental faculties; but oftener merely limiting or obviating the drowsy self-complacency and thoughtlessness which are produced by any excess of the coarser fermented liquors; it can scarcely be ques- tioned that they have exercised a vast and beneficent in- fluence on the two last centuries of Mankind. Indeed, what between their direct influence in promoting mental activity and bodily comfort, and their office not merely as substitutes but as antidotes for alcohol, it is no fanciful estimate of their value to regard them as greatly answer- able for that diffusion of mental industry, and of mental acquirements, which constitutes the most striking psycho- logical phenomenon of the condition of the European races of Mankind in the present day. And it is either an extraordinary coincidence, or a remarkable illustration of the degree in which the experience and observation of Man ultimately lead him to the satisfaction of his most delicate and complex requirements with all the precision originally conferred by instinct on the lower animals — 346 TEA AND COFFEE. that two plants, widely dissimilar both in their botanical affinities and in their geographical distribution, should yield, from two no less diverse parts of their structure, products which, prepared by no less dissimilar treatment in each case, afford the materials for two aqueous decoc- tions or infusions, possessing much the same dietetic uses; associated (as chemistry shows) with a composition in which the three main ingredients — an alkaloid, an astringent, and a volatile aroma — exhibit what is almost an identical constitution, and are combined with each other in no very dissimilar proportions. Tea, when not adulterated, consists of the young leaf- buds, stalks, leaves, and seed-pods of two species {Thea bohea and Thea viridis) of a shrub which, according to Linnaeus, is allied to the well-known Camellia. Hitherto grown for European consumption chiefly in the hilly dis- tricts of the Chinese territory, between the 20th and 35th degrees of north latitude, and the 110th and 125th de- grees of east longitude — to the northern or Tartar region of which it is probably indigenous — it seems destined to a large and successful cultivation in several analogous climates ; and especially in British India, on the southern slopes of the Himalayas. The distinction of the tea imported here from China. into the two varieties of black and green, seems, both from the earlier researches of Lettsom, and the recent travels of Fortune, to be based exclusively on various details of its collection and preparation. The green tea, which is dried more slowly, and at a lower heat, evidently retains a far greater amount of its original strength and flavour; COMPOSITION OF TEA. 347 a circumstance in which such a difference of preparation seems to act on the Tea-leaf, much as it would on the flavour and associated characters of many other vegetable substances, such as Potatoes, Onions, Mushrooms, &c. The finer teas are picked earlier in the season, and hence consist of smaller and younger leaves. Coffee is the bean or albumen which, together with the fleshy husk enclosing it, constitutes the fruit of a Kubia- ceous bush or tree bearing the same name (Coffea). This shrub is said to be indigenous to various districts of Eastern Africa ; whence its culture has successively spread to Arabia, Persia, Ceylon, Java, and America. From the analyses made by Mulder, it would seem that — in addition to variable quantities of many other ingre- dients, probably of less importance — a thousand parts of tea, as ordinarily imported, include the following con- stituents : — Volatile, ethereal, or aromatic oil 8 parts. Thein, (according to Peligot) . 58 Tannic acid . . 158; Extractive .... . 208' Dextrin ...... . 98 Albumen .... . 27 In contradiction to the observations of Frank, Mulder has also shown that green tea contains more ethereal oil, tannic acid, and extractive, than black tea. The darker colour of this latter tea seems to depend on the partial development of various empyreumatic products, as well as on the influence of that greater atmospheric exposure to which it is subjected. Conformably with such a view, it 348 TEA AND COFFEE. would appear, from Mulder's and Peligot's observations, that the black tea not only contains less of the above con- stituents, but that they are present in a much less soluble form ; so that nearly one-eighth less of soluble matter is taken up from it by boiling water, and a longer time is required for its infusion. The soluble ingredients of tea generally range from 29 to 46 parts per cent, of its weight, as shown by its loss when thus infused. All the newer teas are said to be avoided by the Chi- nese ; as unwholesome, and productive of various nervous symptoms. And it is evident that green tea must be re- garded as owing its strength to a greater retention of vo- latile ingredients; even while its delicacy is in some degree heightened by the immature (and therefore weaker) pro- perties of the leaves composing it. A physiological, or rather a proximate, analysis would divide the Tea-leaf into three parts, having very different relations to the system. The fragrant, volatile ingredient which may be distilled off from the infusion, is highly poisonous. Dr. Lettsom showed, a hundred years ago, that it is capable of paralyzing the hinder extremities of a frog, and even of causing death when introduced through a wound into its abdomen; and that it produces, in the human subject, the well-known symptoms of nervous agita- tion, nausea, and debility producible by an overdose of green tea. The remainder of the infusion is a bitter astringent extract; stomachic and exhilarating, if not provocative of appetite. The thehi which it contains seems, according to Lehmann, to produce effects akin to those of the volatile ingredient, when taken in large (10-grain) doses, and in COMPOSITION OP COFFEE. 349 isolation from the other ingredients. Lastly, in the rude preparation adopted by the Tartars, who mix their tea with food so as to eat the leaves, as well as in the mode of tea-making formerly ascribed to the inhabitants of Java, who take the pounded grounds with the infusion, a variable proportion of its albumen and salts will doubtless be taken into the system. The analysis of coffee has yet to be made, so far as re- gards the nature and composition of the bean when pre- pared by roasting. Even as respects the raw bean, we can scarcely estimate the more important ingredients so pre- cisely as might be wished. Payen's analysis, for instance, exact as it seems to be, is strangely contrasted with the results of some other observers. According to it, how- ever, the more important ingredients may be arranged as follows : — Fatty matters (and some aromatic oils) 12* parts per cent. Sugar, dextrin, &c. 155 >> Caffein ; free, and combined with tannic (caffe- tannic) acid and potash 4-5 >5 Salts ..... 7* >) "Water ..... 12- J) Legumin and an azonized substance 4- J> The process of roasting seems" to drive off all its water of moisture, and some of its other volatile ingredients, thus causing a loss of 15 to 25 per cent, of its weight. At the same time, as in the case of black tea, the heat to which the roasted bean is subjected converts its extractive ingredients into a mixture which is more slowly, as well as incompletely, dissolved by subsequent infusion. 350 TEA AND COFFEE. What substances are hereby developed to forrn the strong aroma, can scarcely be conjectured. But it is said that this odour depends mainly on some modification of the caffeic and the caffetannic acids, the latter of which is thus severed from its caffein base. Physiologically, the unknown quantities and qualities of the ingredients of roasted coffee must doubtless be ar- ranged in groups like those of tea. A fragrant, volatile ingredient, which imparts its characteristic odour to the urine : — the special channel of its escape, with little change, from the body. An extractive, which is taken up in larger quantity from a decoction than an infusion. And lastly, ingredients, insoluble and proteinous, which are left in the " grounds " ; and which, though doubtless alimentary, are only consumed in so far as the powdering and infusion of the coffee permit them to remain suspended in the liquid as ordinarily drunk. It is probable that these three classes of constituents produce effects analogous to those of their chemical cor- relatives in tea. At least my own experiments entitle me to affirm, that the aromatic volatile ingredient, which is dissolved by infusion of the coffee in boiling water, and (as connoisseurs know ) becomes dissipated by long decoction, is the chief source of the stimulant and anti-narcotic effects of coffee. This conclusion is con- firmed by the observations of Lehmann. To decide the exact nutritive value of tea and coffee is a task confessedly beyond our existing knowledge to effect. Both as to their general uses, and the details of their action on the economy, we have but few facts : and these THEIR PHYSIOLOGICAL EFFECTS. 3oI few too inexact (and perhaps too casual) to justify any satisfactory conclusion. That they contain few materials capable of assimilation or conversion into bodily tissues is sufficiently shown by their composition and preparation. That they are, in the main, useful ; and that the mass of mankind can habi- tually use them without detriment to health or longevity, are propositions none can fairly question. Indeed the systematic assertions of the Arabic and Chinese writers of their direct influence in protracting life, are, on the whole, to be received rather as impressions derived from ex- perience, than as the flatteries of national habits. Sub- stances which fight their way into general use against all the difficulties imposed by prejudices of race, or nation, or custom, are pretty sure (as may be instanced by opium and tobacco) to have had their disadvantages exaggerated, rather than overlooked. But in what precise way they are useful is a question more difficult to approach. Common experience indi- cates that their occasional (and in a minor degree their habitual) use has a threefold effect. Taken in moderation, they bring about a state of mental cheerfulness and activity, which seems to be closely connected with that sleeplessness their fuller dose can induce. They economise, and partially replace, assimilable food ; rendering the ap- petite somewhat less keen, and so enabling hunger to be appeased by a smaller or less nourishing alimentary ration. And they further seem to diminish the constitu- tional, as well as digestive, requirements of the system; not only allaying hunger, but permitting Nutrition to 352 TEA AND COFFEE. be maintained at what (so far as we can see) is its normal levels under a systematically more scanty or monotonous allowance of food. How far these cerebral (or rather nervous) and nutri- tional effects depend on each other — how far, in other words, a heightened energy of the most subtle and domi- nant part of our machinery may not in itself suffice to de- termine a greater perfection or intensity, or a more exact regulation, and precise direction, of those reactions which constitute Nutrition — it is difficult even to conjecture aright. But there are traces of plausibility about such a view. Certainly few can gain from tea or coffee more than one of these two kinds of advantage. The hard-working day- labourer may make them tantamount to food ; the student may use them as a stimulus to cerebral activity, and a spur to mental effort. But I think it would generally be found that the latter of these two effects so far destroys the former, as to suggest that the increased mental labour of the student exhausts the very same nervous activity, which mediates the nutritive or alimentary usefulness of these stimulants to the labourer, by whom that activity is not thus expended at the source of its origin. But hitherto the facts collected on the nutritional in- fluence of tea and coffee are generally regarded as point- ing to a very different conclusion. Protraction of vital processes, and hence, diminution of vital products ; checked or decreased metamorphosis, as evinced by a decreased extrusion of carbonic acid, urea, and faeces ; — these are the details in which, as observed or deduced by various ac- curate and painstaking physiological chemists, we are THEIR PHYSIOLOGICAL EFFECTS. 353 asked to receive the chief (if not exclusive) explanation of the acknowledged value assigned by the experience of ages to tea and coffee. The facts bearing on this conclusion have been ascer- tained chiefly by the toilsome and exact researches of Boecker * 3 Lehmann f, and others, and may be summed up as follows : — The well-known influence of both tea and coffee in diminishing appetite, and satisfying the organism with a smaller quantity of food, is confirmed by the per- sistence of the bodily weight when they are substituted for a certain fraction of the food. In like manner, under a diet otherwise identical, there is a great diminution in the total amount of the various egesta, when tea or coffee replaces water. Under the use of tea, indeed, this diminu- tion equals about f lb. daily, of which about one-half is water. As respects their resemblances and contrasts, not only may it be asserted that the former are great, while the latter are small; but especially that these contrasts seem to refer almost exclusively to quantity or to degree, rather than to kind. The broader nutritional changes, for in- stance, inferred by Boecker and Lehmann from their ob- servations, are for the most part alike in the cases of * Boecker, Beitraege zur Heilkunde. Crefeld, 1849. f Lehmann, Annalen der Chemie und Pharmacie, Band Lxxxvii. Ueber den Kaffee als Getraenk in Chemisch-Physiologischer Hinsieht. It deserves, however, to be noticed that in his Physiologische Chemie (Band i. 143, and ii. 414), Lehmann alludes to some experiments made with Thein on five persons, as showing under the use of this alkaloid an increase of urea, such as he is in doubt whether to refer to a transformation and elimination of this highly azotised substance. A A 354 TEA AND COFFEE. both agents. The daily excretion of urea, the daily exha- lation (both pulmonary and cutaneous) of water, are di- minished by tea and coffee. Both, too, I would add from researches of my own, undertaken on persons found to be amenable to the law noticed by Dr. Bence Jones *, defer and protract the digestive process. And, at least in some individuals, there is probably a still further agreement in their action, in the fact that the diminution of the daily faecal evacuations by the use of tea (as shown by Boecker), is producible by coffee also. The only contrasts deserving special notice are : — that coffee diminishes (4 to 3), while tea leaves unchanged, the exspiration of carbonic acid ; and that coffee increases (9 to 10), while tea diminishes (35 to 34), the watery ingredient of the urine. The other differences may be almost summed up in the statement, that the operancy of coffee transcends that of tea ; as, for example, in the proportionate lowering of the daily quantity of urea by £, instead of -tV ; of uric acid \ 9 instead of \ ; of the exhalation of water 4-4, instead of -^ ; and also in its protracting digestion during ia period which I should roughly estimate as amounting to at least double that increase of duration which is brought about by an ordinary black tea. Fastening their attention chiefly on this limitation, or rather decrease, of excretory urea and carbonic acid, Boecker and others have regarded the action of tea and coffee as that of checking metamorphosis {Mauser-hi - mende or moulting-impeders) in the various tissues of the * The alkalescence of the iirine during the gastric digestion of a meal, as noticed at p. 120. THEIR PHYSIOLOGICAL EFFECTS. 355 body. But while it must be confessed that such a view is quite compatible with the deleterious properties they exert in large doses, and in some persons, it is not easy to see how it explains the well-known benefits far more com- monly and constantly derived from their use. Nay, more, it may be added that 5 if we confront such an interpreta- tion of the facts observed with the higher laws, and more exact and numerous facts, which Physiology offers, we shall find reasons for regarding it as erroneous. To raise, to better, to facilitate the vital functions by checking metamorphosis, is in flat contradiction with all that we know of Life ; with all that we feel of its fluctu- ations in our own bodies, or see of its manifestations through- out the whole Animal Kingdom. So far as we dare use such shallow and simple words for such deep and complex meanings, Life is flux ; change ; metamorphosis. Within natural limits, the amount of such flux measures the intensity and healthiness of our living. The checking or diminishing of the healthy w T aste is a modification which, in our own bodies*, would be associated with a lowering of health and activity ; and which, as effected by Nature (so to speak) in descending the Animal scale, seems always to be brought about at the expense of the total of Life ; in other words, of the quality or quantity of the collective vital functions. It is interesting to point out, that a diminution in the mere quantities of the crude ingesta, or even of the ul- * Benedek (Annalen der Chemie tmd Pharmacie, Bd. lxxvii.) has made some interesting observations -which strongly confirm the above view, as exemplified by the Urine. A A 2 356 TEA AXD COFFEE. timate egesta, is perhaps compatible with a more perfect and complete execution of that Nutritive function, which elaborates the former into the latter class of substances. But this suggestion, though deserving of notice, ought scarcely to be further insisted on. For it is by the hasty adoption of such plausible suggestions that both persons and Sciences are often trammelled in the search after truth. Nor would it be prudent to push, to what might perhaps be considered its legitimate conclusions, that view respect- ing the twofold destiny of food already (p. 21) arrived at : by surmising that there may be agents which possess the power of so regulating the mutual relations of these two streams of alimentation (if I may use such a term) ; as to diminish the vascular and collateral destiny of the food, while they increase its other and more essential office in connection with the tissues. For, to speak frankly, it may be doubted whether this fundamental doctrine has strength and independence enough to sustain so important a super- structure. But the objections from larger facts — and especially from that law of animal Life just alluded to — are strength- ened by a critical consideration of these experiments them- selves ; which offer several defects suggesting caution in making them the ground of any large and general con- clusions. Habit and idiosyncrasy, for instance, are de- tails difficult exactly to appraise, but easy to recognise in the everyday action of these very substances. The Ger- man, for instance, sometimes describes tea as more stimu- lant and anti-narcotic than coffee ; the Frenchman as a medicine, or an appetiser. The Englishman would pro- EFFECTS ON DIFFERENT PERSONS. 357 bably demur to both these conclusions ; and consider tea, which he habitually uses, as far less stimulating, and less preventive of sleep, than coffee ; or if he found coffee more nourishing, would often recognise a partial expla- nation in the much larger quantity of milk which many habitually consume therewith. Individual peculiarities again, exceed, and often simulate, those produced by habit. Some persons must toss to and fro for a whole wakeful night if they are deprived of their accustomed tea an hour or so before bed-time. In some the quantity of urine is increased by tea, in others by coffee.* Some habitually check a diarrhoea with coffee, while others (and this is much more common) can provoke a similar flux by the same agent. Of course the quality of the tea or coffee, the roasting of the latter, or the strength of their pre- parations — cceteris paribus, the decoction being generally stronger in respect to these actions than the infusion — may affect each of these results. But it may also be po- sitively asserted that they are often altogether independ- ent of any such casual and obvious circumstances. * A not unfrequent effect of tea in some persons is to retain, and collect, as it were, in the system, a large quantity of water ; which, in three or fonr hours, begins to pass off very rapidly as a copious secretion of limpid urine, so watery as to irritate the bladder to very frequent micturition. The skin, in such cases, seems to share in this retention of water, being cold, pale, and almost dry from want of sensible perspiration. It is hardly necessary to add that the various meteorological circumstances of these cases quite forbid the view of any increase in the water of exspiration sufficient to counterpoise the watery deficit of the skin and urine during even a part of the period observed. On the other hand, it is a matter of far more universal experience that in warm, or even temperate, weather, tea cools those who drink it ; and apparently by the ordinary process of a gentle perspiration. A A 3 3S8 TEA AND COFFEE. It is to common facts like these, vague and trivial as they at present seem, that we must look for a check or confirmation of even such admirable and exact researches as those of Boecker, And when we all know what a change a cup of good tea or coffee can effect for most of us on a raw cold morning; or (better evidence, because larger) how such liquids have gradually almost displaced, under the guidance'of instinct and experience, the spiri- tuous liquors formerly consumed under great exposure to cold (as in the cases of railway guards and Arctic voyagers, both of whom, by the way, profess to find coffee the better of the two in this respect) ; we shall do well, know- ing what we do of the production of heat, and the general import of our sensations of comfort, to doubt whether some figures or facts have not slipped out of joint in these praiseworthy but complex inquiries. Further, I would say, look to the experiments them- selves The urine which is examined comprises accurately enough the day's secretion ; subject, that is, to none but such chemical errors as were probably reduced to a mini- mum, or even excluded altogether. But the carbonic acid of a large number of hours, nightly, is not taken ; some- times though these very hours presumably follow that of the ingestion of the substance under inquiry. And lastly, what is a much more serious objection to the whole re- sults, a very large and important fraction of the egesta is, of necessity, always obtained by calculation. In other words, while the exspiratory carbonic acid is estimated from observations necessarily imperfect and interrupted, the total constituents of the cutaneous and pulmonary exha- INEXACTNESS OF EXPERIMENTS. 359 lations are calculated, as a mere subtrahend of the other egesta, from the bodily weight — to speak accurately, are guessed, but never observed at all. It is to this flaw that I would specially call attention ; the more so, that to do so may spare us some allusions to it elsewhere. So long as experiments of this kind are obliged to omit all direct and trustworthy measurements of the cutaneous exhalations in general, and of the watery and organic constituents which are discharged with the carbonic acid of expiration, we cannot accord to them more than an analogical, or probable, value. Exactness, indeed, must necessarily be wanting. The watery vapour, for example, evolved by the skin and lungs is contingently re- ferrible to various sources ; to the water of the external atmosphere, to the water of the tissues, and to the com- bustion of their hydrogen. To whichever of these sources it is really due, its calculated amount affords no indica- tion; nay, more, might remain absolutely the same, no matter how much had entered and left the organism in the same time, if only (what is no impossible supposition) the total quantities taken in, and given out, by ail channels closely approached each other. And a similar proposition holds good, though in a less marked degree, respecting the carbonic acid and urea which are more directly estimated in these researches. The variable and important proportions of carbonic acid which the skin and the urine together eliminate, afford a cloak quite ample enough to cover the small differences detected ; even while our ignorance of the amount of this non-exspiratory carbonic acid in Man forbids us all re- A A 4 360 TEA AND COFFEE. liance on the mere analogies furnished by those animals, of very different size and organisation, in whom it has been directly estimated. And a like uncertainty exists with respect to that waste and decomposition of the azotised tissues which the urea and uric acid of the urine tolerably represent. There are good grounds for supposing that the ammonia exhaled from the skin * and lungs, and con- tained in the faeces — perhaps even the ammonia of the urine, as well as its nitric acid — sometimes constitute a total, the variation of which is quite large enough to de- mand an accurate estimate, before we can accept, in their minutest details, any moderate variations in the daily ex- cretion of urea f by the kidneys only. * Compare the remarks on the ammonia of the skin and excretions generally, at pp. 7 and 15, with the important observations of my colleagues, Dr. G-oolden and Dr. Bernays, alluded to in the following chapter. f In the passage of the above remarks through the press, I am enabled, by the publication of Dr. E. Smith's able and ingenious researches as to the effect of these and other agents on the respiration, to convert some of these surmises into positive assertions, based upon facts such as seem beyond the reach of disproof. He has shown, for example, that tea, added to a food otherwise unvarying — and not (as he shrewdly points out was sometimes done by Boecker) substituted by a more potent nourishment, milk — increases the quantity of urea; and that, too, in a quantity which the careful details of his experiments entitle us to suppose no mere trans- formation of the nitrogenous alkaloid of the tea can explain. He also shows that tea, coffee, and cocoa, all increase the exspiration of carbonic acid ; and in a degree in which the above order of succession represents a decreasing energy. It is hardly necessary to say that it is not my purpose to claim, for Dr. Smith's numerous researches, the position of perfect and unquestionable accuracy in all their details ; or for his conclusions, that of being without exception irrefragably based upon the facts he has adduced. And it is evident from what is said above, that I should be little disposed to accept COCOA AND CHOCOLATE. 361 Cocoa and Chocolate. — The various preparations of the West-Indian Cocoa-nut (Theobroma cacao) which form the cocoa and chocolate of commerce, constitute articles of food having characters very different from that of the tea and coffee which they often substitute in the diet of those who habitually consume them. The nut in its husk, which latter constitutes about 12 per cent, of the whole mass, is rarely made use of. But the husk is said to be ground up in some of the coarser cocoas ; and is even stated to yield, alone, a decoction having sufficient of the flavour and nourishing properties of cocoa to repay a scanty importation into Ireland for this purpose. The shelled nut or bean is stated by Johnstone* to have the following composition. any sudden and temporary fluctuations of exspiratory carbonic acid as proving increase or decrease in the whole process of bodily waste : or the mere fact, that the ingestion of starch caused no immediate increase of exspiratory carbonic acid, as a proof that it did not increase any part of the vital interchange ; by itself becoming, in some form or other, and after whatever delay during digestion or assimilation, subservient to metamor- phosis. But Dr. Smith's researches, even if hereafter qualified in any such respects, will still have given us some facts of striking novelty and value ; as well as some information respecting the conditions of such experiments as those made by Boecker, Lehmann, and himself, which must greatly aid all future inquirers. The class of substances termed " Arresters of Meta- morphosis " was, even prior to his researches, one which, on the general physiological reasons above hinted at, has long seemed to me unworthy of acceptance. But the direct disproof Dr. E. Smith has now given to some of the chief statements on which it was based, will probably be more widely appreciated, than all the indirect facts and arguments which have hitherto been at the disposal of the Physiologist. * Chemistry of Common Life, vol. i. p. 227. 362 COCOA AND CHOCOLATE. Shelled Bean. The same dried. Water . 5 Fat 51 Starch, gum 22 Sugar or starch 22 Gluten 20 Casein or gluten 21 Oil (cocoa-butter) 51 Ash 4 Theobromine * . 2 Theobromine . 2 100 100 In all but the quantity of theobromine (which, by the way, is stated to be an estimate, as though it were not de- duced by any direct analysis), the above proportions cor- respond so closely with those given by Lampadius f, as to suggest their being derived from the analyses of the latter chemist. The above composition affords a tolerable clue to the ingredients of the several preparations of the nut in common use. The heat to which it is exposed developes an aroma, ascribable to a volatile oil, the chief source of which is no doubt the buttery or oily constituent of the original mass. In this respect the " torrefaction " under- gone by cocoa offers analogies to the more energetic roast- ing applied to coffee. The subsequent processes of manu- facture vary according to their object: sometimes being a minute division or trituration of the mass into a condition w^hich better incorporates its oily and other ingredients, and thus aids its further preparation or cookery ; some- times admixing it, while in this finely divided state, with * This alkaloid is distinguished from Thein chiefly by its more azotised composition, and smaller solubility (Caife in =C s H 5 X 2 2 ; Throbroniine = C 9 H 5 N 3 2 ; corresponding with 29 and 36 per cent, of nitrogen respectively. t Dr. TJre's "Dictionary of Arts, Manufactures, and 31ines," vol. i. p. 680. THEIR DIETETIC EFFECTS. 363 starch and sugar, or with ingredients which, like the vanilla of chocolate, add their independent aromatic and stimu- lating qualities to the whole. The dietetic effects of the various kinds of cocoa and chocolate thus manufactured may be summed up as differing chiefly in the degree in which the above processes of purification and incorporation are rendered available by subsequent cookery. The infusion of the husk, for example, is little more than a weak aromatic and stimu- lant, (akin to, but far transcended by) tea and coffee. That decoction of the " cocoa-nibs " which, after long boiling, is decanted off these crude masses, carries more of the starchy and oily ingredients, as well as of the theobromine ; and is therefore more nourishing, as well as a more potent stimulus. Even here, however, the aromatic and bitter so far predominates, that this light preparation is well borne by many persons whose stomachs resent the ordinary cocoas and chocolates. In these latter, in which more or less of the solids of the mass — often, indeed, the whole of them — are drunk in a state of suspension, together with a variable quantity of milk, so large an amount of nourishment is conveyed into the system, and so small by comparison is the influence exercised on the nervous system, that it is difficult to determine any close affinity between their action and that of tea and coffee ; or to recognise any comfort or stimulation as produced by them, beyond what their highly nourishing ingredients will abundantly suffice to explain. They are, indeed, nourishing foods, rather than stimulating drinks. As such, they are often excellent substitutes for tea and coffee in persons whose constitu- 364 TEA AXD COFFEE. tions resent as injurious the nervous effects of these stimu- lants. They are also well adapted to nations and climates where a smaller quantity of solid aliment is generally sufficient. On the other hand, their properties suggest what experience shows to be necessary precautions as to their use by delicate persons. Many who use them to replace tea or coffee, are obliged to select the lightest preparations ; all others overburdening the digestive organs with superfluous materials for absorption. And in many instances it would be found that unless the solid food were correspondingly diminished, chocolate would be too rich and heavy an article of diet ; so much so, that its habitual and excessive use is accused of producing peculiar cuta- neous eruptions, and hepatic derangements. Against the latter danger the Spaniards are said by Ford to adopt the precaution of drinking a large tumbler of cold water, im- mediately after taking the cup of thick chocolate which often forms their breakfast. 365 CHAP. XI. ALCOHOLIC DRINKS. Alcoholic Drinks. — Their Eelation to Food. — Their Classes. — Wine. — Its Typical Varieties. — Their Composition : as influenced by various Cir- cumstances. — Bordeaux and Burgundy. — Sherry, Madeira, Port. — Effer- vescing Wines. — Spirits. — Beers or Ales. — Physiological Effects of Alcoholic Drinks. — Pathological Effects. — Action of Alcohol on the Functions. — On the Metamorphosis of the Body. — Researches of Boecker and others. — Objections to their Conclusions ; to their Facts. — Elimina- tion of Alcohol. — Its Influence on Vicarious Secretion. — Its Action on the Organism. — Its Influence on Bodily Temperature. — On Bodily, Mental Exertion. — Its Indirect Value. — Its Eeaction. — Its Influence on Longevity, in Individuals, Populations. — Teetotalism. — Influence of Alcohol on Digestion ; on Ingestion. — Eisks of Sudden Abstinence. The possession of a large alcoholic ingredient is the cha- racteristic of a group of liquids, which exercise a profound and important influence on the whole function of nutri- tion ; and which, as a matter of statistics, enter largely into the habitual ingesta of the civilised world. How far, however, these liquids are really food in any more intrinsic sense than that of being habitually con- sumed in company with substances more strictly ali- mentary, is a question which we may remit to the follow- ing statements to decide. How far, indeed, the selection of their alcoholic ingredient as the type of their compo- sition is accurate, either chemically or physiologically, may equally be questioned. On the whole, we shall do 366 ALCOHOLIC DRINKS, better to regard their alcohol as their main ingredient only; and as forming, both in respect of their compo- sition and effects, but one extreme of their character. It is certainly their more poisonous constituent. But it is doubtfully their most useful one. And it ranges, through many substances which we know of, and through many more we are obliged almost to ignore, to others which are essentially nutritive. Hence we shall not be far wrong if we approach the study of these alcoholic drinks with the impression, that they may be best classified by their well- known effects, as seen in both individuals and nations ; and are thus something between food and poison ; and, therefore, akin to physic. Pleasant physic, per] But assuredly not pleasant without a purpose on the par" of beneficent Nature. For every gratification of this kind, however it may demand the habitual rule and restraint of higher motives, is yet in itself a direct incentive or reward to the action which evokes it. The three great classes of alcoholic drinks (spirits, win 3 3 and beers or ales) are distinguished by certain broad generic characters, although some of their varieties almost m< into each other. Spirits, for example, are characterised by being the products of distillation; which process collects. from a dilute and complex alcoholic liquid, a volatile mixture containing a larger proportion of alcohol, with a smaller admixture of the volatile matters heretofore a— - elated with it, and none at all of the fixed ones. Wii ^ again, are the juice of the grape, prepared by a sponta- neous fermentation. Beers are the liquids produced by & fermentation, excited artificially in an infusion of the THEIR PROPORTION OF ALCOHOL. 367 saccharised " malt " into which certain starchy grains are converted by heat and moisture. But the artificial sweet- ening and flavouring of spirits makes them u liqueurs" and doubtless endows them with some scanty germs of a fermentative process. And, to say nothing of the fraudu- lent adulterations which disgrace the commerce in wine as well as in every other necessary of life, the avowed sweetening of some nines, and the no less unconcealed addition of brandy to others, converts them also into the same hybrid class of u liqueurs*' sometimes into mere varieties of dilute spirits. Beers, again, range from those admirable tonics, the bitter ales now brewed (which in their effects almost emulate many of the advantages of wines), to a noteworthy ingredient of vinegar on the one hand : or to a heavy, sweet, luscious liquid on the other. And the alcoholic constituent of the three classes shows equal fluctuations. We may, it is true, estimate it as averaging 50 to 75 parts per cent, for the spirits: 10 to 20 for the wines : and from 6 to 9 for the beers and ales. But the wide extremes of different qualities and specimens of each of these three classes, deprive such an estimate of all practical value. The strongest ales, for example, show more alcohol than do the weakest wines : the strongest* wines than the weakest spirits. And it must never be forgotten, that the influence of these liquids, whether we judge that influence by its intoxicative power, or by its more remote and recondite constitutional effects, is by no means that of their alcohol only. On the contrary, their benefits are, as a rule, inversely as their alcoholic ingredient : or, in other words, the mischief they can and 3G8 ALCOHOLIC DKIXKS. * do effect is, other things being equal, rather some high power of their fluctuating proportion of alcohol, than any mere arithmetical proportion of this constituent. Wine.-^- Among the three classes, wine claims precedence. And among wines, we may take as types t€ red " and "white" wine; good old words, which one reads with respect and regret in classic English literature despite their having been for years somewhat restricted in their meaning by the fraud of our tradesmen, and the ignorance of our lawgivers. Eed and white wine, such as kind Providence offers to the industry of civilised Man everywhere throughout a wide district, which ranges from the Atlantic on the West, to Palestine (the very home of the grape, and the place where its use was hallowed by the Son of Man) on the East. Eed and white wine, neither the costly results of extra- ordinary soil and culture on the one hand, nor the ill- grown, ill-made, ill-kept stuff which torments even the " dura ilia mcssorum" on the other. But the sound fresh small wines which, in ordinary years, can be grown in any reasonable quantity along a line of latitude extending from Spain to Hungary, both inclusive ; and which, thanks to one of our greatest modern statesmen, bid fair to resume •the ground they have lost during the last century in England.* * The arguments in defence of a system which had for many y rendered wine unknown to the mass of Englishmen, would scarcely deserve to be raked up from the fitting obscurity they have now found, were it not that they strikingly illustrate that want of acquaintance with the and laws of human Life, which renders some of our most successful poli- tical controversialists perfectly unfit to legislate for the physical welfare of their fellow-citizens. To say that wine was an inferior or unwholesome COMPOSITION OF WINES. 369 The composition of such wines may be formulated as follows : — Bed. White. Alcohol (by volume) . 120 110 Free acid . 6 9 (Tannic acid . 0-8 0*3) ^Ether . traces (0*025 ?) (0-025?) Colouring matter . — — Sugar . 3 4 Extractive . 30 25 "Water . 841 852 1000 1000 This estimate, inexact but not arbitrary, is quite com- patible with the fact established by the numerous analyses it sums up ; namely, that every one of the above con- stituents is subject to such wide variations, as to have drink in this climate ; that the English workman would never drink wine ; that the foreign peasant would never grow it for him ; that wine was a luxury, and therefore to be taxed to the verge of prohibition : — such were the assertions which, for years, those who should have been the instructors of the public substituted for more legitimate arguments in defence of our strange laws against one of the first necessaries of civilised existence. Hardy predictions deserve no contradiction until those who make them can show some claims to be considered prophets. But how men who had lived during the wars of the first Napoleon, and ought to have known the importance of wine in his Commissariat, and even its share in some of his victories — how they could call wine a luxury only, and appraise it on so- phistical grounds which, carried to their logical conclusions, would entitle us to regard potatoes, water, and a single fig-leaf as the only necessaries of human Life, it is really difficult to understand. Certainly the experience which teaches some persons that they can dispense with such aids to Nu- trition, or the more doubtful considerations which league others in hos- tility against all alcoholic drinks, no way countervail, either the general usefulness of wine, or its special value as a less poisonous and brutalising agent than the ardent spirits which, in most countries of Europe, replace its insufficient consumption. B B 370 ALCOHOLIC DRINKS. but an approximate value. The variety of grape used ; the climate and soil in which it is grown; and every detail of the preparation and preservation of the wine from its juice; all modify the result in respect to each of the in- gredients above noticed. For example, the effect of a clear dry climate, with a bright powerful sunlight, on the grape itself, is well shown by a contrast of the rich strong wines of Spain, Italy, or Syria, with the thinner wines of Northern Grermany and Holland ; in which latter country the ripening of the grape to an adequate size and sweetness is in some sea- sons a matter of great uncertainty. The injurious effects of too rich an animal manure, and too moist a soil, are equally well known ; as are also the exhaustion or de- terioration of soils which, though formerly the homes of generous wines, are now quite incapable of supplying them. In like manner, the concentration of the mast by evapo- ration; the access of air during fermentation, and the changes which accompany the later stages of this proc the precipitation of albumen, tannic acid, and bitartrate of potash ; the decrease of sugar ; the increase of alcohol ; and its subsequent loss by evaporation: — all tell upon the com- position of the wine to what is often a remarkable degree. An old wine will therefore show less alcohol than a new one of the same kind ; often also much less sugar, some- times none at all. An old red wine generally deposits a crust of tannic acid and bitartrate of potash : and only retains a certain shade of colour, which scarcely exceeds that of an old white wine; and which is derived (according to Mulder) from the same modification of tannic acid. BORDEAUX AKD BURGUJNDY WINES. 371 the sparingly soluble apothema of Liebig. Lastly, it is reasonable to conclude that age confers other benefits be- sides those attributable to the above chemical changes ; and especially, that it imparts to the whole liquid a homoge- neous character which, as in the case even of a factitious and adulterated wine, tends to deprive it of part of its injurious effects. Few better illustrations could be adduced of the con- joint effect of some of the above circumstances, under but moderate variations of climate, culture, and preparation, than a contrast* of the finer red wines of the Bordeaux and Burgundy districts (the Grironde and Cote d'Or respec- tively) : — Bordelais Bourgogne {by Faure). (by Delarue). Alcohol . 9-188 13-480 Tannin . -112 •079 Bitartrate of potash . -160 •057 Tartrate of the peroxide of iron . -089 •006 Other salts . -025 •065 Colouring matter . •041 •078 Water . 90-085 86-235 100-000 100-000 Popular opinion in France regards Bordeaux as not only less heady or intoxicating, but (even apart from this character) more wholesome than Burgundy. It is interest- ing to find some explanation of this very wide experience in the larger ingredients of tannin (l± to 1); of salts (nearly 2 to 1); and especially of iron (about 15 to 1), contained in the Bordeaux wines. As regards all of these, Revue des Deux 3Iondes, Juillet 15, 1860. B B 2 372 ALCOHOLIC DRINKS. we may perhaps trace the rule, that it is the natural but multifarious admixture of ingredients in wine which makes this liquid generally so much less poisonous, and more medicinal, than dilute alcohol ; even while this very cha- racter may perhaps demand for it changes akin to a diges- tive process in the liver : and hence that the due subor- dination of its alcohol may well make any particular wine more useful. And in respect to the tartrate of iron of the above analysis, it is important to observe that its absolute quantity — from 6 to 7 grains in a pint — amounts to a full medicinal dose in the quantity of wine often consumed daily by those who habitually drink it. In name, at least, Port and Sherry rank as among the " wines ; " of which liquids they have till recently been the sole representatives with the mass of our nation. But it is doubtful whether, as a matter either of chemistry or of dietetics, they fairly deserve this title. Sherry, for ex- ample, is understood to be composed of various wines, so mixed and incorporated as to suit the prevailing t of the British consumer; wines, some of which are artificially strengthened by evaporation, while others are coloured (innocently enough) by burnt sugar. So far as the preparation of Madeira implies any similar mixture or reinforcement, it, too, must be ranked less among the wines than among the u liqueurs ; " of which, indeed, it de- serves, on every ground, to be regarded as the chief. The addition of brandy to wine is of course a rank adulteration ; which, physically, may be mitigated by the incorporation brought about in course of time, as a slow continuous fermentation of the whole mixture ; but morally, remains EFFEKVESCENT WINES — SPIRITS. 373 always indefensible. As regards Port-wine, the exact com- position and sources of this orthodox beverage are still a profound mystery to scientific chemists ; even in the case of that moderate proportion of the liquids bearing this name, which is believed to be really imported from any wine-growing country. Assuming it to be vinous, we may estimate its alcohol as tolerably corresponding with that of Sherry and Madeira, in amounting to a proportion nearly double (20 parts per cent.) that of the ordinary natural wines as above estimated. The effervescing wines are distinguished, not only by the carbonic acid they evolve, but also by the large propor- tion of sugar they contain. About 5 per cent., for ex- ample, seems to be the proportion of this ingredient in good Champagne. Their alcohol usually exceeds that of the common or natural wines; amounting to about 14 per cent. In various sweet non-effervescent wines, little used at present, though apparently far more popular two or three centuries ago, the per-centage of sugar rises to 20 or even 25. The distilled spirits, ranging from 50 to 77 per cent, of alcohol (Gin being the weakest, Eum the strongest), are otherwise distinguished by peculiarities of taste and smell ; due to ingredients which are derived from their respective sources, but are often scarcely determinable by a quantita- tive analysis. In the " liqueurs " usually so termed, a large proportion of sugar (as in Noyau, Maraschino, Curapoa) is often present as an admixture to the alcoholic basis. In Noyau, the flavour communicated by bitter Almonds is of course associated with a proportionate amount of the BB 3 374 ALCOHOLIC DRIXKS. energetic poison thus added ; although the quantity is usually too small to exercise any independent effect. The beers or ales, ranging in alcohol from 3 to 13 per cent., and in sugar from 2 to 25 per cent., with a small (2 per cent.) proportion of free acid, are also distinguish- able by those other ingredients (especially their bitters) which make up their complex " extractive" In the physiological effects of these various liquids, the proportion of alcohol plays a prominent, but by no means exclusive, part. Hence, though we may trace something like a gradation of activity in passing down that alcoholic scale which conducts from the strongest distilled spirit to the weakest beer, we find some differences which are specific to the three classes of spirits, wines, and beers ; as well as others which apparently depend, in great degree, on the relative proportions of the above collateral ingredients. The quantity of sugar, for instance, is evidently of im- portance; and, in general, greatly increases the noxious effects of the liquid in which it is largely present, acting in this respect as no mere admixture of sugar with the food would do. The aethers and the tannic acid, as well as the tartaric acid and the tartrates, of wine, are also doubtless of importance ; and seem to confer upon it that rich and multifarious composition by which this great medicine so far transcends all that we sometimes attempt in our pharmaceutical combinations of many drugs. Lastly, there is the clearest evidence that another quality — which, for want of a better word, we may call naturalness — of wine is still more influential : and that this character {m the exact appreciation of which the chemist must at present THEIR PHYSIOLOGICAL EFFECTS. 375 be content to rank below the connoisseur, and the con- noisseur in his turn below the sensations which follow a moderate dose, or the constitutional effects experienced by the habitual consumer) is the only one which guaran- tees that proper combination of stimulant, tonic, and alterative effects distinctive of the action of wine. But although it is by the physiological effects of these liquids that we ought especially to decide their respective value, both as aids to food in health, and as remedies in disease ; it is precisely in respect of these effects that we should probably find most diversity of opinion to prevail. The large experience afforded by the human race during many thousand years is often rendered equivocal by the collateral circumstances under which that experience has been obtained. In few details, again, would any number of persons be found to differ more widely from each other more than in the effects of alcohol on their diverse consti- tutions. And Chemistry, Physiology, nay, even Politics and Ethics all press in, with evidence often conflicting, to disturb and complicate the question, important as it is to the destiny both of states and individuals : — " What is the benefit, or the mischief; in one word, the value; of this or that alcoholic drink ? " After all, it is to the large facts afforded by common experience that we may best look for evidence upon very complex and obscure subjects. And the rule of proceed- ing from that which is known, to what which is unknown, is, in this case, no less agreeable to philosophy, than con- venient for purposes of disputation. That " wine makes glad the heart of man," not even B B 4 376 ALCOHOLIC DKINKS. the rules of modern exegesis will enable us to deny. And that, in quantities equally moderate as those to which this proportion must virtually be restricted, it so far substitutes and replaces food, as to permit life and health to subsist for an apparently indefinite period, on a food less rich or copious than would otherwise be re- quisite, is scarcely more questionable. The immediate and casual results of its excessive use, as a matter of ordinary observation, might be described in the words of our greatest of dramatists ; from whose works, indeed, it would be easy to collate * an exact summary of all its more important physiological effects : such as its in- fluence on the brain ; on the limbs ; on the sexual, urinary, and cutaneous functions. And that the several changes thus produced throughout the organism by an alcoholic ex together make up a general condition capable of being summarised as a downright poisoning, is a fact signifi- cantly expressed by that genteel metonymy which, un- wisely slurring over the cause of this state, and confining attention to the effect it deuotes, describes a person as " intoxicated," whom our ancestors would have more ac- curately though bluntly stigmatised as " drunk." The frequent repetition and perpetuation of this poison- ing, even in less marked degrees, often produces various conditions which our existing Patholoo-v is tain to regard as diseases, merging into the apparently similar conditions which are witnessed in temperate persons, perhaps as the results of other poisons. And though it is doubtful * Of such passages, that in M Macbeth," (Act ii. Scene 3) Is one of the most characteristic. EFFECTS OJST THE NERVOUS SYSTEM. 377 whether there be any disease whatever which, directly or indirectly, alcoholic excess cannot invite, provoke, or aggravate; it is certain that there are some which it specially and largely produces, as an effective cause. Of these delirium tremens, nephritis, and cirrhosis of the liver, afford the most frequent and best attested examples. In passing on to notice those more exact and scientific observations, by which it has been attempted to trace into their details these well-known facts concerning the phy- siological action of alcohol, we need only allude to the several degrees and kinds of that immediate or direct effect which it produces on the nervous system. Pleasur- able excitement, increased mental cheerfulness and activity, and (quite compatible with this stage) a gradually increas- ing bewilderment of sensation and of motion, usher in a torpor, ending in downright coma. Nor can it be denied that other phenomena — namely, those of inorganic life — exemplify an analogous inversion (so to speak), as the result of alcohol. Thus the improved digestion often brought about by a small and dilute dose is contrasted by the nausea, vomiting, and complete suspension of this function, which result from a large one ; the turgidity and excitement of the whole vascular system in the first stage of drunkenness, by the pallid bloodlessness, and the feeble cardiac and arterial impulses, of the last stage. In like manner, the furtherance of sensation and of motion, which are at first produced by alcohol, and which finally merge into an annihilation of both, evidently do so through an inter- mediate state, in which it is easy to recognise that it is perception and not sensation, co-ordination of movement, S78 ALCOHOLIC DRIXKS. and not muscular contraction, which are in fault. The " enemy " which the drunkard " puts into his mouth/* does, indeed, exactly fulfil the Shaksperian simile, by acting in the first instance, so chiefly, if not exclusively, on his nervous centres, as literally to " steal away his brains.** The more profound nutritional effects of alcohol have of late years been generally summed up by a doctrine, against which the author has long felt it necessary to protest as a hasty, if not incorrect, generalisation of facts, such as them- selves, above all others connected with the physiology of alimentation, demand a careful sifting, and an accurate judgment. Ever since the brilliant views of Liebig on this point were first propounded, evidence has seemed to be gradually accumulating in confirmation of them. Yier- ordt, Boecker, and others, have indeed supported them by researches, the care and industry displayed in which are beyond all praise. And hence it has cine to be almost a received doctrine of the schools — a kind of idohvm tl<> — that alcohol economizes waste, and aids Nutrition, by diminishing both the products, and the process, of meta- morphosis in the tissues : among which products the urea and carbonic acid in which carbon and niti ogen are ulti- mately dismissed from the system of course figure as the most measurable and important. The statements of these observers substantially assert, that under the use of moderate quantities of wine and other alcoholic liquids, the daily evacuations of carbonic acid and urea of a healthy male adult, are reduced by about one-eighth and one-fourth of their respective pre- vious quantities. It would further seem, that not only DIFFICULTIES OF EXPERIMENTS. 379 do the three classes of alcoholic drinks act differently ; but that even the red and white wines may presumably be contrasted in the circumstance, that the influence in limit- ing metamorphosis which is common to both, is soon followed, in the case of the white wines, by such an in- crease of waste, as renders these alterative in the strictest sense of this word. In demurring to this generalisation, however, I must not be understood to question the facts. And while, in such a momentous question, there is need of great caution in appraising these facts themselves, it should not be for- gotten that the very difficulties which oppose such obser- vations, are a testimony to the skill and pains of these observers. For example, a person eating at will may be easily con- ceived to receive and use less food when moderately stimulated by alcohol. His previous habits, again, will be likely so greatly to modify the results of the experiment, that we can well imagine any man but an habitual Tee- totaller fretting all his tissues under an unaccustomed abstinence from alcohol ; and returning, with the return to his habitual ration of this stimulant, to a more moderate bodily and mental expenditure ; — in other words, to a diminished wear and tear of his whole system. And not even a savant could be quite trusted to gauge the degree in which that mental and bodily irritation which abstinence, and moderate indulgence, in alcohol might thus excite, and relieve, respectively, had probably affected the chemi- cal results ultimately obtained. The greater objection to such experiments is, however, 380 ALCOHOLIC DKIXXS. that danger of idiosyncrasies which some of these observers themselves especially suggest. And waiting, with them, for numerous studies of this exact kind, we may in the mean time fairly compare the narrow, though exact, facts they have communicated with the more trustworthy, if less detailed, information, which is derivable from a larger experience. Now, could any physician, judging with that delicacy of observation which the practice of Medicine (and especially, the art of diagnosis) teaches, suppose that tea; coffee, and alcohol, might be grouped together ; that their main in- fluence on Nutrition was alike, much more identical ; that their effect on the tissues was analogous? Assuredly not. And yet this is substantially what we are asked to do. We are told of each in succession, that it economises the bodily substance : checks and diminishes that waste, of which carbonic acid and urea are the exponents and the results. If this then were their value, it would seem that the habitual drinkers of alcohol, tea, and of coffee are all taking the same path ; that health, economy, and longe- vity are the goals which all will finally arrive at, and by almost identical tracks. But before tracing this objection into detail, let me repeat, in even stronger terms, what I advanced before. Supposing metamorphosis to be limited in exactly the way assumed, how should we call this economy ? Meta- morphosis is so far identical with Life, as to be at any rate the coefficient of all healthy vital action. And it has yet to be shown how its diminution can improve or economise life and health ; how, in short, a traveller would get more KELATION OF LIFE AND WASTE. 381 economically to his journey's end by merely taking a railway-ticket which announced a lower fare than that payable for conveyance to his destination. To suppose that a man has only so much metamorphosis to effect in a lifetime, and therefore must perpetually strive to moderate this waste, is a low view of the mystery of Life, quite un- warranted by anything we know of the subject. As well ignore cleanliness in cookery, upon the old nautical plea, that every man must eat a peck of dirt before he dies ; or adopt Balzac's ghastly legend of the u Peau cle chagrin." Commercially such a view does, indeed, seem neat enough. But even so, it might fairly be rejoined (and that on the strength of analogies which have a far higher import, and sanction) that Man is a trader, and not a stagnant holder, of Life or any other gift ; and that as the healthy waste of the tissues which represent the servants and carriers of his profitable trade must generally correspond with the amount, and the profits, of his transactions, it would be the very worst economy to aim at increasing these by a mere re- duction in the numbers and activity of his staff. And, as respects the alleged diminution of the daily excretions of carbonic acid and urea under the moderate habitual use of alcoholic drink, it is probable that the observations hitherto made are amenable to other errors than those producible by the idiosyncrasies or habits of a few subjects of experiment. A single blot in the intervals selected for the analyses, a single unexpected* peculiarity * This very explanation has lately been adduced by Dr. Edward Smith to invalidate some of the experiments hitherto most relied on. He finds that " alcohol alone, and each member of the class of alcohols, has its own 382 ALCOHOLIC DRIXKS. in the time or the fluctuations of such an effect, might well convert a real increase into an apparent decrease, or produce these small differences which are all that seem to have been observed. Further, even if we assume that these ordinary products of bodily waste are really diminished by alcohol, it will by no means follow that the process itself has undergone degree, and even kind of action." In his valuable researches on the in- fluence of the alcoholic liquids upon the exhalation of carbonic acid, it was especially his object to avoid the difficulties which had opposed accu- racy in the experiments of his predecessors : in whose inquiries the sub- stance was taken in doses unusually large or frequent, with various kinds of food, at different periods of the day, and with varying degrees of tion ; so that it was difficult to dissociate the influence of oth and even yet more difficult to obtain a .standard to compare the results. To avoid these difficulties he the moraL for the inquiry, when the system was very sensitive, and no influence of food existed; and when, during perfect reet, all interferences were rem and the effect of the alcohol isolated. This method also allowed of a correct standard of comparison; the amount vf chemical cL re the fluid was taken. His chief results were as follows: — Alcohol diluted with water incn the amount of carbonic acid evolved, in a very moderaf Rum had a similar but more decided action. "Wines commonly caused an incon- siderable increase. Brandy and Gin generally lessened it : as did w. also, though with a manifest tendency to return to. or exceed, the ori„ quantity. Old ale and Stout always caused a sustained increase for a two hours. Of course the observations thus briefly noticed by no means exhaust this difficult and complex question. Nor is it quite impossible that the longer observations of Boecker, extending over many days, and the shorter ob- servations of Dr. Smith, restricted to the two hours before breakfast, may be found to afford an explanation of some of the discrepancies in their results ; a temporary increase not being incompatible with a direct or in- direct decrease of the carbonic acid exhaled during a day or a ser: days. But Dr. Smith's elaborate researches have at any rate opened up a new and important series of tacts, as well as afforded some indispensable means for future and larger inquiries. THEIR EFFECTS OX THE SKIX. 383 a simple and corresponding diminution. Apart from the argument that, on all analogy, such a decrease would be a step backward if not downward, a regress towards a smaller degree of Life, if not a lapse in the direction of disease ; observation suggests (at any rate supports) a doubt whether the process may not be so far changed, as that its products may undergo a substitution by others allied to them, its own amount perhaps remaining unaffected. For example, few of the greater phenomena of Xutrition are more changed by alcohol than is the function of the skin. The unnatural flush, or the deep ruddy hue of the drunkard's face during a debauch, is scarcely more cha- racteristic than is the more permanent colour of all the exposed parts of his integuments. And we may un- questionably observe an analogous, if smaller, effect of this kind, as the ordinary result of a moderate use of fermented liquor ; so much so, that among persons equally exposed to the air, the pallor of the Teetotaller will generally distinguish him at a glance from the ruddier consumer of beer or wine. Xor is it a mere increase of colour which the skin thus shows; but its heightened vas- cularity is associated with a great increase of its secretion : an increase which is traceable, in marked cases, by an increased exhalation both of water, and of those volatile fatty acids which constitute so large and important a pro- portion of the cutaneous transpiration. In moderate drinkers, it may be fairly supposed that this effect is partly due to an elimination of the poison by this channel; and that, just as the ethereal and allied con- stituents of fermented liquids can be plainly recognised by 384 * ALCOHOLIC DRINKS. their smell, which shows them to be habitually dismissed from the body in the pulmonary exhalation ; and others just as notoriously find their exit by an increased flow of urine ; so various ingredients of alcoholic drinks pass out by the skin, stimulating its local action, and increasing its various secretions in their transit. But it is also possible that such effects are partially due to an arrest of that metamorphosis which furnishes the normal secretions of this organ ; to an imperfect oxidation, which substitutes for the ordinary products of combustion (carbonic acid and water) matters representing intermediate stages of the process. According to such a view, the skin, surcharged with the materials of its function, and unable to accomplish their complete change and removal, permits or effects their exhalation in a state of oxidation far short of that which they ought to possess. This condition of the cutaneous egesta, as well as its cause, seem analogous to that excre- tion of fatty acids (p. 267) which takes place in an animal fed for a time exclusively on fat. Nor are indications wanting of far more important dis- turbances which, if producible by alcohol in the chemistry of Nutrition, would deprive all moderate variations in the daily excretions of carbonic acid and urea of the signifi- cance hitherto assigned them. The formation of water, which is always deduced, rather than verified by obser- vation, represents a kind of combustion such as might (and in many diseased processes undoubtedly does) replace or substitute the formation of carbonic acid, in a degree such as a moment's consideration would show to be capable UREA ESCAPING RECOGNITION. 385 of permitting the greatest variations/ both in the degree and kind of the waste it represents, and in the equivalents of heat evolved by a given loss of substance. Hence a mode- rate diminution of carbonic acid proves little as to the waste of the tissues, unless it be quite certain that there is no corresponding increase of water of combustion. In like manner, even urea seems to have its counterparts, which may render its own decrease a mere subterfuge (so to speak) of the chemistry of excretion. Among these it is scarcely necessary to specify the carbonate of ammonia ; which is suggested by many facts of health and disease to be a ready and simple modification of urea, capable of ex- halation from the whole surface of the body, and therefore of escaping all but the most delicate and specific search.* While, whatever doubts still hang over the exhalation of pure nitrogen from the body, it may be conjectured that the interesting observation of Dr. Bence Jones as to the * Careful observations entitle me to state that the moderate and beneficial use of alcohol sometimes largely increases the ammoniacal con- stituent of the fieces ; and apparently, in a lesser degree, that of the skin and lungs. [Since writing the above,, the suggestion made here and elsewhere (p. 4) as to the directness of the relation between ammonia and urea in the cutaneous and other secretions, and the possible secretion of urea by other organs than the kidneys, to undergo a speedy (and perhaps spontaneous) conversion into the carbonate of the volatile alkali, has received a striking confirmation from some valuable observations by my colleagues, Dr. Goolden and Dr. Bernays, relatively to the action of the Turkish bath. A fine healthy young man, inured to the bath by his avocation as one of the attendants who shampoo the visitors, thoroughly cleansed the surface of his whole body with soap, and plentifully washed this away with warm water. The sweat which poured from his skin under the influence of the heated air was carefully collected by Dr. Goolden, who directed and watched the C C 386 ALCOHOLIC DRIXKS. formation of nitric acid in the system^ affords a clue to another serious source of uncertainty as regards all deductions founded merely on scanty variations, or small fractions, of the urea excreted daily. Lastly, it is quite possible that an increased secretion of mucus from the alimentary and respiratory tracts, as well as of the ordinary fluid and solid excretions of the skin, might conceal such an increased evolution of azotized ingredients as could cover a small diminution of daily urea, From all these considerations we may perhaps infer, with tolerable certainty, some important conclusions re- specting the action of alcoholic liquids on the organism in general ; conclusions which may be conveniently men- tioned here, and which are in some degree independent of the circumstances to be next alluded to, much as these tend to illustrate and confirm them. (1.) It is evident -whole experiment. Analysed by Dr. Bernays. this sweat revealed the fol- lowing composition : — Water ..... 992 S Urea . . . . .IS Chloride of sodium . . . .42 Remaining ash . . . .1*2 1000 It is not for me to anticipate the line of induction Dr. Goolden has so well begun. But, apart from the not improbable contingency that the urea thus excreted may represent a larger amount, part of its equivalent ammonia being lost from the experiment as thus conducted, — it is evident that the amount of urea presumably got rid of by a single bath, during which two pints of sweat are often poured out, might well form a large and important relief to the kidneys, and to the organism at large. For example, assum- ing the estimates of Vogel and Xeubauer, it would follow that from ^ to ^ (=tV t0 A^ °f tne ^hole daily urea of some patients, might th eliminated through the skin.] THEIE PHYSIOLOGICAL ACTION. 387 that alcohol acts, first and most, on the nervous system ; through which it chiefly influences the tissues in general. (2.) Not only is there no proof whatever of its " assimila- tion" in the strict sense of the word, — as implying a liken- ing or conversion of alcohol or its constituents into the substance of the body, — but even that combustion which it has often been supposed capable of ministering to, seems to be contradicted (certainly remains unconfirmed) by accurate inquiry ; and, so far as regards those slender facts on which it may be regarded as resting, is certainly susceptible of other explanations, themselves more com- patible with the predominant or exclusive influence of this drug on the nervous tissues. (3.) Though the rough and unaided evidence of the senses as to the elimination of alcohol by the skin, lungs, and kidneys, has not yet been followed into its exact details of duration and quantity by the incontrovertible evidence of exact chemical analyses, yet it may be fairly presumed that a process of removal of the drug, without much change as regards some of its ingredients, really obtains. A partial elimination of this kind must indeed be regarded as quite established by the evidence already at our disposal. And it is evident that a large (perhaps even a total) elimination remains not quite impossible ; a proposition which is, in some sense, a corollary of that which denies its assimilation.* * Recent researches (Ludger Lallemand, Maurice Perrin, et J. L. P. Duroy: Du Bole de V Alcbol et des Ancssthesiques dans V Organisme, Becherches Experimentales, 8vo. Paris, 1860) have now given exactly the information thus vaguely hinted at as wanting to decide the action of alcohol. The careful experiments of the above observers may be summed up as establishing: (1.) That alcohol, after its ingestion, undergoes a c c 2 388 ALCOHOLIC DRINKS. Eeverting to larger facts, it can scarcely be questioned* that even a moderate daily ingestion of alcohol diminishes the capacity of the body for resisting extremes of tem- perature. That, other things being equal, healthy men are cooler in Tropical climates, and warmer in Arctic ones, under a total abstinence from alcohol, is a proposition which has now been abundantly established by numerous excellent authorities amongst travellers and scientific ob- servers. And while the normal relations of the organism to temperature constitute the maintenance of an uniform bodily heat an exquisite test of health, — and, indeed, imply the perfection of animal Life and organisation, — so those simple laws of combustion and evaporation that are at least the instruments through which the body exerts its opposite powers of warming and cooling itself up and down to a fixed temperature, show that alcohol is, in the main, a special accumulation in the tissues of the liver and the brain ; two 01 of which the predominant selection of one is mainly determined by its relation to the channel by which the drug enters the system : — the liver being the first to receive the alcoholised blood which comes from the intes- tines; the brain bearing the brunt of alcohol injected into the veins, or inhaled into the pulmonary capillaries. (2.) That the kidneys, skin, and lungs are the channels of its exit from the body unchanged. (3.) That the duration of this process of elimination, though varying to some extent with the quantity of alcohol taken into the body, may be estimated, in the case of an ordinary dose of wine, as removing the whole of the drug from the system in about 24 to 36 hours. The minute and delicate chemical details by which these results have been obtained, will doubtless receive a criticism tar more practical, and therefore more satisfactory, than can be based upon a mere study of the above Essay, without a careful repetition of its experiments. But in the absence, hitherto, of any such repetition and confirmation of these experiments, it is only right to say that they seem to defy disproof, as well as to establish the conclusions which have been based upon them. THEIR INFLUENCE ON MUSCULAR EXERTIOK 389 source of nutritional derangement; and that its use is incompatible with the perfection of Nutrition. Exertion, again, in all its more active forms, whether this activity find vent in a short but excessive muscular effort, or in a more sustained but less violent action, is just as certainly disfavoured by alcohol. Careful observa- tion leaves little doubt that a moderate dose of beer or wine would in most cases at once diminish the maximum weight which a healthy person could lift, to something below his Teetotal standard. While, even as respects more sustained exertion, the avoidance of feverishness, and the capacity of prolonged muscular effort, are gladly secured by many who habitually drink alcoholic liquid*, by a temporary abstinence from it under such circumstances. In like manner it is not too much to say that mental acuteness, accuracy of perception, and delicacy of the senses,, are all so far opposed by alcohol, as that the maximum,, efforts of each are incompatible with the ingestion of any moderate quantity of fermented liquid. Indeed, there is scarcely any calling which demands skilful and exact effort of mind or body, or which requires the balanced exercise of many faculties, that does not illustrate this rule. The mathematician, the gambler, the metaphysician, the maitre cVarrnes, the billiard-player, the author, the artist, the physician, would, if they could analyse their experience aright, generally concur in the statement that, even though * The Chamois-hunters of the Austrian and Bavarian Alps well illustrate this remark ; a remark, however, only amounting to a reiteration of one of those rules of athletic training, the value of which rests on the experience of some thousands of years. c c 3 390 ALCOHOLIC DRINKS. they may find a bottle of wine, convivially speaking, not a drop too much ; and a more moderate potation quite com- patible with the exercise of all their faculties ; yet that a single glass will often suffice to take (so to speak) the edge off both mind and body, and to reduce their capacity to something below what is relatively their perfection of work.* On the other hand, however, it is necessary to remember how often the whole question must practically be ap- proached from a totally different aspect ; how often alcohol constitutes, not the single feather which distracts the sleepy savage, but the bed of down which restores the exhausted man. It may disturb a balance exquisitely adjusted; and yet, in the main, counterpoise a scale heavily laden with disadvantages. If alcohol exhilarates ; imparts comfort and energy ; counteracts fatigue, hunger, and unrest ; then it does in effect increase the capacity for work of those who take it under such circumstances ; and affords, in so far, a direct benefit and advantage. It is, however, alleged that not only does it thus solicit and bribe (as it were) the individual to undue and hurtful exertion, but that its advantages are dearly bought by that stage of reaction or depression which follows the excite- ment it produces : in short, that it invites to suicidal ex- cesses of work, and stores up the mischiefs which it defers. The first of these two statements has a great degree of truth, as well as much more plausibility. But, on the * The influence of alcohol on imaginative effort is quite another matter ; though even this influence, if analysed aright, and traced to its end. would perhaps support no very dissimilar conclusion. THEIR INFLUENCE ON HEALTH. 391 whole, it is difficult to avoid expressing a deliberate opinion, that neither of them really applies to the mo- derate use of alcohol. The Teetotaller would doubtless be justified in asserting, that the toil which requires the habitual use of large quantities of alcohol ought never to be done at all; and that, to allege that the day's work can only be prepared for by doses of wine or spirits, is tantamount to a confession that the work is utterly unfit for the existing health and strength of the workman. And it is matter of only too common observation, that the hilarity produced by an excess of alcohol overnight, is often followed by great indisposition and depression the next day. But to restore by a glass or two of wine those sensations of comfort and cheerfulness, which have been somewhat worn during a long day's work, is a procedure which, though it may often be indirectly necessary to similar industry on the morrow, seems quite compatible with the continuance of good health. And, in like man- ner, the man who feels worse on the morrow of a social dinner, which has been enlivened by a moderate quantity of good wine, may thank himself, or his host, for a reaction which proves some error in either the quantity or quality of his compotations. From good wine, in moderate quan- tity, there is no reaction whatever. Id respect to longevity, the exact influence of alcoholic liquids in moderation has yet to be made out ; both as regards individuals, and populations. The practice of Physic sufficiently teaches us that, as above suggested, there are many persons whose health is bettered, and life protracted, by its discreet use. On the other hand, it c c 4 392 ALCOHOLIC DRIXKS. cannot be doubted that, apart from the excesses which notoriously poison and kill those who indulge in them, alcoholic drinks, taken in quantities far below what are requisite immediately to affect the brain, often sap the foundations of health ; and constitute the cause (or, at any rate, the occasion) of indigestion and gout. In most cases, however, we observe no sensible effect of either kind ; or find (if we analyse our observations) that the operancy of alcohol is rendered doubtful by other conditions — such as hereditary constitution, circumstances and habits, — which ordinarily transcend and obscure its own action. With fresh air, moderate exercise of mind and body, the heritage of a healthy frame, and plain nutritious food, the hardest and sourest of ale permits Old Parr to attain the extraordinary age of \52 ; and ev^n the Whisky of the Highland shepherd, or the " Schnape" of the German peasant, seems comparatively innocuoua As applied to masses, the question is not less obscure : and demands, on the whole, an equally oracular answer. It is excess which is fatal; and this is unfortunate!] common, that one can hardly doubt the sudden abolition of the use of all alcoholic beverages would at once occasion a general increase of the average duration of Life in a country like our own. But such a supposition, however difficult to realise, suggests other contingencies. Ethical as well as Medical, which cannot be ignored. Certainly, to judge by the only Teetotal populations we are acquainted with, tobacco, opium, and the grossest of sexual vices, have done scarcely less towards the shortening of average life, and the degeneration and decrease of the population, among THEIR INFLUENCE ON HEALTH. 393 the Mahometan races, than the drunkenness which was so accurately painted by Hogarth, and which still claims so large a number of English victims yearly. And, to judge by appearances, there must have been far more and healthier old age (using these words in their literal sense) among the boon companions of London society fifty years back, than could even now be found among the temperate and highly cultivated inhabitants of some of the healthiest cities of Italy. Nor can it be denied that the Practice of Medicine supplies us with a question on which many a Physician is compelled to doubt, though he would be delighted to answer it in the affirmative. That Teetotalism is compatible with health, it needs no elaborate facts to establish ; any more than we need search the records of history, or the narratives of travellers, to find numbers of persons habitually practising such abstinence from alcohol, with none but the best results. But if we take the customary life of those constituting the masses of our inhabitants of towns, we shall find reason to wait for ex- perience before we assume that this statement will extend to our population at large. And in respect to experience, it is singular how few healthy Teetotallers are to be met with in our ordinary inhabitants of cities. Glancing back over the many years during which this question has been forced upon the author by his professional duties, he may estimate that he has sedulously examined not less than from 50,000 to 70,000 persons, including many thousands in perfect health. Wishing, and even expecting, to find it otherwise, he is obliged to confess that he has hitherto met 394 ALCOHOLIC DRINKS. with but very few perfectly healthy middle-aged persons, successfully pursuing any arduous metropolitan calling under Teetotal habits. On the other hand, he has known many total abstainers, whose apparently sound constitu- tions have given way with unusual and frightful rapidity, when attacked by casual sickness ; and many more who, with the strongest resolution and inclination to abstain from alcohol, have been obliged to resume its moderate use, from reasons no less valid and imperious than those which, 1800 years ago, induced an inspired Saint to pre- scribe it for a Teetotal Bishop. It may, however, be suspected that any apparent rarity of the coincidence of perfect health, and complete Teeto- talism, is less of an argument against the claims of this doctrine than at first sight it seems to be. Certainly many of the other habits of our urban populations are, as it were, leagued against such an innovation as absti- nence from alcohol. Bad food ; bad cookery ; foul air ; in- sufficient exercise ; excessive mental and bodily toil ; all combine to render a stimulus of this kind both Lett superfluous, and more harmless, than it would other be : and at the same time suggest, that the imperfect health often seen as the concomitant of Teetotalism should be referred to these well-known agencies of disease, rather than to any less direct and obvious cause like the want of a particular drug. In like manner, that the constitution of a reformed drunkard often foils at a pinch, is a defect which ought in fairness to be charged to his previous habits ; and not to that salutarv change in these habits. THEIR INFLUENCE ON DIGESTION. 395 but for which he would in many cases have lost both health and life long before. Even as respects Digestion, the influence of alcohol is a complex problem to solve. The chemistry of artificial digestion * conclusively indicates, that the mere solution of the gastric contents can undergo nothing but disturbance, | or even opposition, from alcohol ; the injurious effect of which is probably not altogether suspended by any but the most extreme dilution ; and is certainly heightened by its combination with those saccharine and fermenting ingredients which are largely present in most alcoholic beverages ; and which tend to set up, in the gastric con- tents, a decomposition akin to their own. But the oc- casional experience, that alcohol assists Digestion, is not absolutely incompatible with these chemical effects. For not only may its influence on the mind, or on secretion, outweigh that more direct injury to Digestion above spoken of; but even these effects themselves may (and often do) exert a salutary reaction on the system, and through it on the digestive canal ; obviating — perhaps oftener defer- ring and accumulating — some of the direct consequences of excess. That good eating requires good drinking, has in all ages of the world been admitted : and to select the most invidious illustrations of this fact, the gigantic meals which are sometimes ended by the slow soaking in dilute alcohol of almost all the food taken — so as to check alike Digestion and decomposition, and enable the intestinal canal to void its contents after a very scanty absorption of their nutritious principles into the blood-vessels — would * Compare p. 124. 396 ALCOHOLIC DfilNEB. scarcely be compatible with the health sometimes associated with them, save by an effect of this kind. The removal of such a questionable safeguard against excess, is therefore one of the results of Teetotalism. And though it is alleged that the habitual consumption of a much larger quantity and variety of food by Teetotallers is an instinctive compensation for the want of all alco- holic stimulant; yet, recollecting the natural tendency of Mankind to forego moderation in their pleasures, just in proportion as the number of these pleasures becomes restricted, it may be questioned whether this increased ingestion of food may not have a different source: whether, in short, most men are not likely to pay the more attention to the solid luxuries of the table, when these are the only enjoyments of the kind which they can command Far from the Teetotaller being subjected t<> the need of an unusually rich and copious Dietary, personal observation and experience would suggest that he may claim a higher ground for the doctrine he advocates. It is true that the insufficient ingestion, and still more insufficient Digestion of food, is one of the commonest and v results of alcoholic excess : by which the organism is thus deprived of food, at the same time that it is prostrated by the copious introduction of an active poison : and hence that, contrasted with habitual excess of this kind, Teeto- talism provokes the cravings of a healthy appetite, and implies a larger consumption of food. But it is quite otherwise if complete abstinence from alcohol be com- pared with another grade of indulgence in it. Looking to that large class of persons whose habitual quantity of RISKS OF THEIR SUDDEN WITHDRAWAL. 397 food is regulated only by instinct and taste, and contrast- ing the total abstainer from fermented liquids with the moderate consumer of them, the former must be regarded as the more economical eater of the two. For he digests so much more thoroughly and completely what he does take, that he requires less (rather than more) food than a person who, in circumstances otherwise similar, indulges moderately in some alcoholic beverage. While he certainly has lost that safeguard which alcohol in some sense affords against those varieties of dyspepsia forming the more im- mediate results of over-eating. The risks of a sudden change from habits of indulgence in alcohol, to a total abstinence from it, cannot be fitly con- sidered in a mere outline of the principles of Diet ; but are related to a variety of circumstances, more strictly medical. The degree of such indulgence, the state of the patient's health, and a variety of equally obvious details, so mate- rially influence the consideration of every such case, that no rule can be laid down for the procedure to be adopted. Perhaps, however, one may hazard the general remark, that, save where alcohol is enabling a worn-out constitu- tion to bear up against some of the lesions it has itself provoked, an immediate and complete abstinence is both safer and easier than is generally supposed. Certainly, for the majority of persons addicted to excess, such a proce- dure is, both on medical and moral grounds, the only route to amendment. And any one forsaking such habits need not fear to run the gauntlet of those symptoms to which proper medical treatment will always reduce the sufferings that notoriously pursue the first steps of the reformed 398 ALCOHOLIC DRINKS. drunkard on the rough path of repentance. But for those who find that health is preserved or benefited by moderate indulgence in some dilute or natural form of alcoholic drink, no rules can be offered : unless it be (mindful of the significant Italian epitaph*) to let well alone; or, if higher (even though mistaken) motives suggest a change of habits in respect to this good servant, but bad master, of the mind and body, not to carry out such a change rashly. For them, the modification of habits has not that vast predominance of benefit which it has for the drunkard ; but is a change which, on every ground, must be made with prudence, and followed by careful observa- tion. And the application of a few such hints upon diet and habits as most educated Physicians could afford, would often prevent injury to the Teetotaller's health, and save his doctrine from what is, in many instances, an un- deserved condemnation at the hands of somewhat prejudiced observers. Perhaps, too, a similarly careful observation would often suggest, as well as control, the same change ; and would thus at once cure the dyspeptics who owe many of their symptoms to that moderate quantity of alcohol which they erroneously suppose is indispensable to their health. It is not very rare to find persons whose delicate organs of Digestion resent almost every fermented liquid to such a degree, that they are perpetually teased and fretted by a source of irritation, which eludes all discovery until some casualty teaches them that — to vary the meaning of the French idiom — " ils out le vin onauvaw" no matter how little they take of it. * M Staya bene. Per stare nieglio, sto qui." 399 CHAP. XII. COOKERY. Importance of Cookery. — Comparison of Kaw and Cooked Flesh. — Di- gestive Import of the Changes wrought by Cookery. — Summary of its Advantages. — Process of roasting Meat. — Process of boiling Meat. — Varieties of Boiling; their Objects, and Processes. — French Pot-au-feu as one of these Varieties. — Baking. — Stewing. — Soups. — Their Ob- jects, and corresponding Varieties. — Spanish Pucker o. — Cookery of Flesh as affected by its Decomposition. — Economy of Cookery. The subject of Cookery is one which ought not to be al- together overlooked in treating of Food. For not only do the operations summed up under this term greatly modify the various constituents of the food, but they are, in the main, so necessary and universal, that, however possible it might be to maintain existence on the raw materials fur- nished by the two kingdoms of Nature, we cannot conceive of alimentation being successfully thus conducted, in the case of either individuals or societies. Food, indeed, im- plies cooking. And far from cookery being the matter of mere luxury, or even of comfort, which many affect to consider it, it would be difficult to point out any subject more intimately connected with national health and wealth than that which regulates the absolute and relative value, to every citizen, of the first necessaries of Life. And truly, 400 COOKERY. of all countries of the civilised world, there is none in which a diffusion of the principles of cookery is more needed than our own. For want of some ideas of this kind, the perfection of meat, the profusion of fuel, and even the extraordinary special skill of our cooks, enforce on the affluent a monotonous diet of far too rich and heavy a quality. While among the poorer classes, hitherto little accustomed to flesh-meat, the ignorance still prevalent as to the best and cheapest modes of preparing it for use, recall, if not justify, the old adage ; which, while devoutly acknowledging the gift of food, broadly stigmatises cooks (by a neat antithesis) as missionaries from the Enemy of Mankind.* The claims of cookery, in a scientific point of view, have yet to be fully established. Waiting such information — the acquisition of which will doubtless entitle this modest handmaiden of life and health to take her proper rank among the various Arts and Sciences, somewhere be- tween Chemistry and the Fine Arts — it is difficult to offer more than a general statement of what cookery in general may be presumed to effect ; and of what its chief pro- cesses may be observed to bring about, in the substai submitted to their action. Rightly appreciated, tl processes suggest the principles of cookery : the objects it * The last half of the proverb. M God sends meat, but the devil sends cooks," probably has a special reference to that favourite Eng s 9 — a piece of meat, coal-black without, leathery within — for which popular suj stition might well find a parallel only in the products of those torrefa< offices assigned to Satan in the "Mysteries" of the Middle Aires. At rate it may remind ns of the toil, waste, ill-temper, ill-health, and intem- perance, of which had cookery is so obviously and universally a ca - among the poorer classes. CONTRAST OF RAW AND COOKED MEAT. 401 should have, and the tests by which its successes must be estimated. No better illustration can be found of some of the chief claims of cookery, than in the case of animal food or meat. "We will suppose, for example, a piece of raw flesh to be compared with a similar piece properly cooked : — how, we will not for the moment inquire. After contrasting the external appearances of the two, we may follow them, by the aid of dissection, to the very bounds of unassisted touch and sight; and then invoke chemistry and the microscope to carry this scrutiny into its minuter details. The following would probably be the conclusions thus arrived at. The tissues of the raw meat retain much of that di- versity specific to them during life. Its numerous struc- tures (each with its own substance and arrangement, as well as appearance and composition), are only mixed and broken down into each other by putrefaction ; a condition which may fairly be alleged in some degree to precede that interchange of their proper nutritional liquids, which pre- pares them for their more complete decomposition. In the cooked meat, on the other hand, not only is putrefac- tion delayed, suspended, and even, in its slighter degrees, removed for a while ; but there is an intimate admixture and combination uf the juices of the meat, giving it a homogeneousness or uniformity of flavour which — itself the simple result of combining into one complex admixture many tastes and odours — tends to render all its particles equally tasteful and equally nutritious. And the physical changes of the solids of the meat are no less marked and D D 402 COOKEEY. important. Many of its constituents are dissolved, and mixed in this state with the rich liquids of the original substance ; many more are prepared for their future so- lution by the digestive secretions. The tough insoluble partitions of areolar tissue between the meat-fibres are first converted into gelatine, and are then more or less dissolved and diffused among the surrounding structures. The dense membranes of the fat-vesicles are thinned, softened, and even burst ; so as to allow the escape of their valuable contents, only assimilable when thus exposed and finely divided. And even these details of cookery, in- fluential as they thus are, probably yield in importance to two other elements of this process; elements, however, which can only be vaguely enunciated in the present state of our knowledge. Firstly, it cannot be doubted that the process of cookery includes chemical changes — downright metamorpho« which are, in the main, great improvements of the food. To take no more recondite test, the disappearance of the colour of the blood contained in meat is proof of conver- sions of this kind. Whatever their exaet nature, their usefulness is undeniable. Secondly, I venture to surmise that the scientific import of cookery must be sought chiefly in a direction to which the physiology of Digestion points the way. Whatever the precise shares taken in the processes of cookery by solution on the one hand, or by conversion on the other, both ap- pear to yield in magnitude and importance to another set of changes ; which, for practical purposes, may be regarded as lvinor midway between the two. The method of ob- CHEMISTRY OF COOKERY. 403 servation above specified does indeed conclusively show that their united influence accounts for but a part of the change accomplished by cookery. And though I have as yet no direct proof sufficiently tested by repetition to justify the publication of its details, yet those conclusions to the same effect which may be indirectly arrived at, amount to something more than mere conjecture. Con- trasting the effect of heat at a high temperature, as in cookery, with that enormous and disproportionate increase of putrefaction producible by a low one ; contrasting the coagulation produced by heat on albumen, with the ap- pearances seen in cooked meat ; and especially, remember- ing the sedulousness with which all the culinary operations exclude oxygen ; — we may at any rate find reason for be- lieving that the changes of cookery transcend solution, even while they fall short of decomposition, in many im- portant respects. I should even be disposed to conjecture that they constitute a step towards a process of true hydration ; in which some of the tissues of the uncooked food combine with the water of their moisture, or even mutually interchange the water of their composition : a process of hydration analogous, both in its nature and office, to that more complete and specific change of the same kind, which it is the function of the stomach to accomplish by means of the gastric juice. The flavours developed by cooking are by no means un- important. Most of them depend upon changes of com- position, the exact nature of which remains unknown. Others belong to a process which, while it partially car- bonizes or chars the substance roasted, appears to com- D D 2 404 COOKERY. municate savoury characters, by causing the evolution of various products (empyreumatic and otherwise), which are tenaciously retained by the less volatile and more carbo- nized materials. Hence a prolongation of the process first modifies, and then destroys, the flavours gained by its earlier stages. To these general advantages of cookery may be added some others, more specific to certain kinds of food. The same process of extraction, for example, which dissolves from meat some of its best constituents in the form of broth, and even obtains from bones no • contemptible elements of food, is often useful, in the case of vegetables, by removing soluble ingredients more or less hurtful, sometimes downright poisonous. And, apart from all such use of water as a solvent, even heat can in some insta effect an analogous purification. Thus, then, we may sum up the general advantages ob- tained by cookery. It confers a diversity of tastes or flavours; and thus permits a wholesome increase in the diversity of ingredients originally contained in the food, as shown by the chemistry of its raw materials. Besides ful- filling these instinctive wants of mankind, it purifies, pie- serves, and economizes food ; and presents it to the agency of Digestion in a form which, by facilitating this proc 98, allows Nutrition to be conducted at a smaller expenditure of alimentary materials. Doubtless, it thus allows many climates like our own to he more largely peopled, and it- collective inhabitants to be fed with less aggregate toil than would otherwise be necessary. And in this sense we can scarcely demur to the statement, that, by deducting PROCESS OF BOASTING. 405 from the total quantity of labour which would otherwise be requisite for life, it indirectly adds to the national wealth. A few of its chief operations may now be glanced at. Roasting. — In the operation of roasting meat, the heat applied to the outside of the mass soon converts its more superficial portions into a dense, hard, brownish mass ; con- sisting chiefly of the various tissues originally present here, which entangle in their interstices a quantity of albumen formerly present, in their nutritional juice, but now coa- gulated by heat. This compact crust, which, by its sub- sequent contraction, forcibly compresses the matters be- neath, is of essential service ; not only in moderating the heat thenceforth transmitted through it to the deeper portions of the mass, but also in confining (and as it were sealing up) its numerous liquid and volatile consti- tuents, which would otherwise be soon dissipated in the form of gases or vapours. The heat which now penetrates the mass, probably diffuses the juices of its various tissues at a high pressure throughout its whole texture ; dissol- ving its osmazome or extractive and much of its gelatine, melting its fats, and imparting that comparative uniformity of consistence, as well as of properties, already alluded to. Doubtless some of its albumen is also dissolved in this way : though by far the greater part of this consti- tuent seems to be thrown down as a kind of loose soft precipitate ; which, to all appearance, becomes intimately entangled with the solid fibres of the areolar tissue, en- closing them as a kind of nucleus within its own deposit. The colouring matter of the blood is generally more or less D D 3 406 COOKERY. dissolved in that admixture of the various liquids of the original tissues which constitutes the " gravy." * The nu- merous empyreumatic products, which are developed chiefly in the more heated exterior of the mass, next add the savoury taste and odour, and the deepened colour, cha- racteristic of this mode of cookery. The act of " basting," or (i braising," perhaps helps to moderate the heat of the inside of the mass by evaporation. But it is much more influential by its perpetually renewing — or rather complet- ing — that outside varnish (if we may use such a compa- rison) of the mass, which is as perpetually undergoing dissipation, and even decomposition, by the fierce heat applied here. Of course if the process be unduly pro- tracted, it will not only burn the hard outside shell into a coaly substance, but will also drive off man}* of the volatile constituents of the exterior; and will thu> convert the in- terior into a dense, tough, whitish, contracted mass, far too insoluble for easy digestion. On the other hand, if the roasting is too rapid, and the heat too intense, the same char- ring of the outside is of course attended with a diminution of all the advantages of cooking in the inside or central portion; which is revealed at table in that "bien saignant" condition, popularly supposed by our French allies to be the English taste in respect to the national dish of " Rosbif" Boiling is an equivocal term which ought, for the sake of intelligibility and accuracy, to be either expunged from * It has been supposed that the red colour exhibited by this liquid in the interior of a mass of roast meat, proves that the blood has not o lated ; and therefore, that the heat of 154° Fahr., which coagulates albu- men, has not been obtained. But the above seems the true explanation. VARIETIES OF BOILING. 407 the vocabulary of cookery, or at any rate never employed without some such qualification as may give it an exact import. For example, there are at least three operations of this kind in the cookery of meat ; each absolutely dis- tinct from the other, not only in the object sought for, but in the method adopted, and in the results actually at- tained. In boiling meat with a view solely to the alimen- tary virtues of the resulting solid mass, the object should be to approach as closely as possible to the cookery of roast- ing. Indeed, in whichever way either may be applied, the two processes of boiling and roasting necessarily have something in common. Both are accompanied by a coa- gulation of albumen, a solution of extractive, and a solu- tion (or rather formation) of gelatin, in the mass itself. But they differ from each other, chiefly in the circumstances, that the lower temperature applied in boiling developes no empyreumatic substances ; while the water which conveys the heat to the mass always extracts from it a certain pro- portion of its soluble constituents. Hence to diminish this process of extraction — which is itself pro tanto an impoverishment of the meat — forms a special object of this variety of boiling. And it may be effected by suddenly plunging the meat into water at a temperature of 212° Fahr. ; a temperature which, by coagulating the albumen of its outermost layer, produces a crust sufficiently impervious to enclose and retain some of the more volatile consti- tuents of its interior. On the other hand, when it is chiefly the broth or aqueous solution of the meat which is intended to be used as food — in other words, when it is not the w cooking ' or dd 4 408 COOKERY. preparation, but the complete extraction, of the solid mass which is sought for — the extractive process must be favoured, not only by increasing the surface of mutual contact between the water and the meat, but by delaying and avoiding, so far as is possible, the coagulation of the albumen, and by prolonging the period of the solvent action. Hence the meat should be very finely divided (minced, or even pounded) before infusion ; and the temperature of the water then raised very slowly, to a degree of heat far short of ordinary ebullition, and maintained there for a long time. Of course the proportion of meat must vary with its kind, and even its quality, as well as with the de- sired strength of the broth. But, as a rule, no after dilution should be practised : a mixture of broth and water being a very different tiling from a homogen- liquid containing exactly the same proportion of water. And in all but the hottest weather of this climate, it is both economical and advantageous to soak the minced or pounded meat from four to eight hours in the water, before exposing it to heat at all. The best test of the success of the process is of course the homely one of tasting the product. The next best is the utter insipidity of the shreds and fibres which form the residue — literally a caput mortuitm — of the experiment when it is properly carried out. Midway between these two extremes stands a variety of boiling, which is one main element of that admirable French institution — the "pot an feu;* 1 and which, for its great saving of skill, care, fuel, and food, is perhaps the climax of cookery, viewed from its most important (that is. VAKIETIES OF BOILING. 409 its economical) aspect. To roast aright, demands a large fire, a good cook, perpetual basting, and (last, not least) an excellent meat ; a not inconsiderable proportion of the volatile elements of which are inevitably lost by evaporation, and by the charring of its exterior. . To ex- tract meat with water gives a liquid which, precisely be- cause it demands little digestion, is often most valuable to a sick man, but a very unsuitable food for a healthy one ; whose stomach requires to be filled, and that too with matters containing a fair proportion of solids to elicit its action. To boil meat, after its immersion in water at 212°, affords a broth too good to waste, and yet hardly good enough to form the basis of a soup. The French bouillon and bouilli, broth and meat, are formed simultaneously ; and can be produced with little fuel, from indifferent meat, by an unskilled cook, whose time is scarcely claimed at all throughout the whole pro- cess. And the two elements of the product — liquid and solid — are of almost equal alimentary excellence, each in its own direction of usefulness. Theoretically, the process is one of very slow boiling, in a quantity of water too small to allow of more than an imperfect extraction. The meat, barely covered with cold water, is raised very gradually (in one to two hours) to an imperfect ebullition ; and maintained there for a period roughly estimable as an hour for every pound of meat, the surface of which is kept covered with water by constantly replacing that lost in evaporation. If this process be pro- perly carried out, the result is a meat thoroughly tender and well cooked ; and a broth not only pure, clear, and 410 COOKERY. fragrant ; but sufficiently strong for all reasonable dietetic purposes short of that office of a pabulum, which beef-tea sometimes has temporarily to fulfil for the sick. The time occupied in the process has the incidental advantage -of cooking various vegetables ; the solids of which are thus prepared as food simultaneously with the meat which they supplement, while their soluble and volatile constituents are a grateful and useful addition to the broth. Baking and stewing may almost be regarded as varieties of roasting and boiling respectively. Thus it is chiefly in the uniform application, and moderate degree of the heat ; and in the accumulation, around the meat, of its own watery vapour ; that baking differs from roasting. And it would be easy to show how, according to the perfection of these characters (as in a small clean earthen or brick-oven, heated very slowly and to a comparatively low temperature, and cooled down as gradually), the advantages of roasting may be approached with a far smaller expenditure of fuel and trouble. At the same time it is obvious that with anything short of these arrangements — of which perhaps the cookery (not the food) of Xew Zealand * was for- merly the best illustration — heat would be too great and too penetrating; and the meat, robbed of much of its juices, would be often injured by the empyreumatic flavour added by the oven or its fuel. * The subterranean ovens described by voyagers as capable of baking a whole Pig at once, must have rewarded these happy islanders with a kind of apotheosis of pork, which may be fitly contrasted with the confla- gration supposed by Charles Lamb to have casually taught the Chinese the gastronomic value of roast-Pig. STEWS AND SOUPS. 411 The process of stewing, and the preparation of soups, trench too deeply on Gastronomy to receive here more than some such brief allusions as may range them under the principles of Diet, without attempting to unravel and dis- play their mysteries. Theoretically, a stew and a soup possess thus much in common, as that they seek to secure flavour — which, in the main, is equivalent to wholesome- ness — by a combination of ingredients ; and, at the same time, proffer much of their materials to the alimentary canal in a liquid state, which requires of them little or no digestion prior to their absorption by its vessels. But while the stew contains a large proportion of those various animal and vegetable tissues which claim to be treated as solid food, it would be easy to arrange soups in a kind of scale; which, beginning by the richest, should exhibit such solids in a continually decreasing proportion, and finally reduce them to a minimum of vegetable substances ; or even offer nothing but a thin animal broth, enriched only with the soluble and flavorous constituents of the vegetables used. The boundary between the two being thus indefinable as a matter of cookery, it may seem scarcely necessary or possible to distinguish, dietetically, between a stew and a soup. As is the case with other Arts, however, the suc- cesses of cookery cannot be expected from accident or genius ; but demand that the object, and method, of each process should be understood beforehand. And really if the educated public would spend one twentieth of the time waited in deploring the scarcity of good cooks, in learning and communicating to these " Ministers of the In- 412 COOKERY. terior" the first principles of their art, there would soon be little cause of complaint, where mechanical skill is already so perfect.* What, for example, is the purpose of a soup? The dinner of a labourer's family ? Then it merges into a stew. The preparation for the chief meal of the day in an affluent family ? Then it must be light, and flavor ous ; stimulating little more than absorption ; a mere advanced guard of the troops of dinner. How the same county magistrate, or civic dignitary, who inspects a prison dietary in the morning, can in the evening commence an otherwise ample meal, with a quantity of such soup as Turtle or mock-Turtle, and expect to escape the results of repletion, it is really difficult to imagine ! No better illustration of stewing could be found than the well-known Spanish "puchero; " a study of whicl in all seriousness, worth the attention of those who wish to be unobtrusively useful in furthering the physical well- being of the working classes. The Spaniard's pipkin* cookery — if we may coin such a term — is achieved with the minimum both of materials and of fuel. Xo atom of meat or vegetable is charred or volatilised. Whatever is lost by the solids, is gained by the surrounding liquids. Many ingredients add their flavour, and other properties, to the mixture. And all are reduced to such a physical * There is perhaps no nation in the world which could show so manj proficients as onr own. in that toilsome and difficult process of roasting which is daily accomplished to perfection by thousands of English cooks. Intelligence only is wanting ; and the want of this is. at any rate, not the defect of the cook only. PRINCIPLES OF STEWING. 413 state, as prepares them for the action of the digestive organs ; so that those tough indigestible constituents, which in bad cookery, defy assimilation, and often provoke the neglect or rejection of their more innocent companions, are here absent altogether. It is further to be noted, that the preparation of the "puchero " is based upon the proper recognition of a great law of cookery : namely, that different substances require such different times and heats for their cooking, as baffle alike the clock and the thermometer to regulate. The Spanish cook prepares a variety of meats and vegetables in different pipkins ; and only mixes them, with all the subtlety of the alchemists (from whom perhaps he tradi- tionally derives his knowledge), at the very instant of ec pro- jection." This fact deserves to be recollected, as having a profound significance with reference to cookery in general ; and especially as illustrating the rule already * hinted at, that the juices of the raw materials are themselves im- portant agents in the culinary process. It is not merely the physical tenacity of the tough meat or vegetable which requires a longer heat, or more water to break down. It is rather the quality and quantity of its own juices. So that (as is well known to cooks) every article of food, and every part of an animal or vegetable — indeed, it would hardly be an exaggeration to say every specimen — has its own rate of cooking, which nothing but observation and expe- rience can determine. The time after death at which the tissues of various animals are best cooked also varies extremely. In some, * See p. 401. 414 COOKERY. it may be from unusually rapid and early decomposition, cooking can never be undertaken too soon after death. In others, moderate delay appears to improve the flavour and other qualities of the meat. But it is scarcely necessary to add, that the exact date is decided by climate and me- teorological causes differing in almost every locality and period.* It is still more obvious, that the disgusting and unnatural practice of eating putrid flesh is always un- wholesome, as well as sometimes dangerous by the gastro- intestinal symptoms it provokes. Nevertheless this singu- larly artificial taste does but exaggerate (even though it reverses) the experience of those real advantages which are obtained by moderate keeping. It is probably related to the rigor mortis; and to the way in which this temporary condition often opposes cookery by the physical tough-. * From all these reasons, the size of the animal is one element of its ordinary rate of putrefaction. Its relations To the Buzronnding temperature are of course equally influential, ami are necessarily in great part deter- mined by its cutaneous or other coverings. But it is evident that there are other circumstances, which are inherent to the tissues of the healthy animal, and which exert a great, if unexplained, influence on all the changes these tissues undergo after death. The contrast oi these changes in the Salmon and the Turbot well illustrate such a statement. The latter gains in flavour and digestibility by keeping a day or two : the former undergoes a perceptible deterioration during every hour that follow death. It would probably be found that, in such a contrast, the access the rigor mortis would be at least an index, perhaps even the cause, of the difference. At any rate the flesh of the Salmon seems to owe much oi its heavy and indigestible character to an extremely rich muscular juice: the partial removal of which, by solution and decomposition, is possibly one element of the impoverishment and deterioration it undergoes by keeping : just as its sudden and complete coagulation by boiling water, immediately after death, communicates the " curdy" aspect which delights the Scotch gourmet who can eat it near its haunts, PRINCIPLES OF STEWING. 415 ness, the chemical resistance, and especially the com- paratively unmixed state of juices, which it implies. Cooked before the rigor mortis has had time to set in, the muscular tissues of fish, fowl, and other animals are cer- tainly far more tender and digestible, than if their cookery is delayed until after the advent of this state. Finally, the importance to the poorer classes of economy in cookery, suggests a recommendation of great simplicity, but perhaps of some value. It is bad, because dear, cookery habitually to use any more fuel, time, trouble, or material, than is really necessary. And hence, except among the affluent, or for purposes of variety or gastro- nomy, roasting is not a process to be encouraged ; while wholesale boiling and frying are downright waste. For in all these processes, the outer layer is nearly destroyed for nutritive purposes, in the mere act of conducting and mo- derating the heat applied to it, and of confining the volatile contents of the central mass. So that all procedures which accomplish these purposes with equal (or even in- ferior) efficacy, but more cheaply, would practically have the invaluable effect of adding to the scanty portion of meat habitually consumed by the working man. To dip a piece of flesh in batter, or in a mere paste of flour and water ; and thus sacrifice a cheap, to retain a dearer and more nutritive, material in the process of baking ; is the primitive, but effectual mode which is adopted in many parts of Europe ; with many of the advantages of the meat- pie or pudding of the English cook, or the frying " en jpapillotes " of the French one. 416 CHAP. XIII. CHOICE OF FOOD, OR DIET. Diets ; as Mixtures of the preceding Articles of Food. — Difficulties of their Calculation. — Value of Physiological Chemistry in the Choice of Food. — Absolute Quantity of Food. — Results of Deficiency of Food. — Test of a good Diet. — Uses of its Variety. — Office of Physiology in Reference to Dietetics. — Chief circumstances affecting Diet. — Diet as modified by Age; in Childhood, in Old Age. — Diet as modified by Sex. — By Habits of Life; Confinement, Inaction, Mental Exertion. — By Climate: in Arctic, Tropical, Regions. — By Race. — By Disease. — Diet in Di- of the Digestive Organs. — In Diseases of Exhaustion ; of Repletion. — Repletion; general and casual. — Repletion from checked Elimination ; from general Congestion. — Relation of Instinct t«> Diet — Diet in special Diseases, how appraised. — Fever, a- an Example. — Value of Alcohol in Disease. — Clue to its Uses, and Abuses. — Preferable Mode of its Administration. — Principle of the Choice of Food and Stimulants in acute Disease. Haying thus examined into the different alimentary sub- stances, we may next inquire into that quantity and quality of the food which would be implied by theil admixture with each other, in the proportions best suited to the maintenance of health. From what has already been stated, it is obvious that, in constructing such an ideal diet, or in estimating the proper daily ration which ought to form the food of any individual or class of persons, it should be our first care to ascertain the presence of all the alimentary principles in suitable proportions. HOW FAR CHEMICAL. 417 At first sights it might seem easy to calculate an efficient scale of diet, from no other data but those which the above law affords us. Indeed, it would almost appear that such a knowledge of arithmetic as is implied in using the rules of simple addition and subtraction would enable us to calculate an infinite number of Dietaries. For it would evidently be easy for us to take any forms of protein, hydrocarbon, or hydrate of carbon ; and compare the known per-centage of their elementary substances with the same elements in the carbonic acid and urea which represent the most important products of the waste of the body. Adapting the quantities of the former to those of the latter, we might thus arrange thousands of formula?, in which food would always exactly equal waste, and income expenditure : — formidce which, provided the human or- ganism were really made up of similar figures, would no doubt give us equally definite and satisfactory results when carried out into practice. A variety of circumstances, however, concur to invali- date such calculations, and reduce them to their true value : — namely, the results of mere processes of addition and subtraction, that only distort and obscure the facts on which they are founded. These circumstances prove, that the end of such sums in simple arithmetic is no better than the beginning; that they do but repeat, in a less specific (and therefore less truthful) form, the various chemical statements on which they are all based ; and that, carried any further, they can but mislead the Physio- logist. For instance, not all our existing knowledge of the E E 418 CHOICE OF FOOD, OR DIET. composition of most of the substances commonly used as food> would enable us to construct a diet which would be certain to contain sufficient proportions of all the neces- sary salts. For, in the first place, we must recollect the probable importance of some salts which are only present in very small quantity ; as well as the value which similarly appears to attach to minute proportions of certain organic acids, and of their compounds with bases. In the next place, we must remember that, both in animals and vege- tables, these saline constituents seem liable to vary, in nature as well as in amount, according to the peculiarities of the soil from which they are ultimately derived. It is not by any means easy to insure their presence. Hence a good scale of diet ought to provide against any danger of their deficiency, by adding so much of various fresh ve- getables as would far exceed all possibilities of such an occurrence. Indeed, nothing short of such variety and excess can be trusted to, for the maintenance of the food in a state of perfection, as regards these saline constituents. A similar argument will apply to the quantities of all the other ingredients. The mechanical states of the protein and the hydrates of carbon have at least as much influence in determining their requisite amounts, as the exact quantities which are rendered necessary by the daily waste of the tissues. Hence, to this latter estimate we have always to add a large excess ; such (for instance) as may cover the sur- plus protein which passes, — undigested or indigestible — with the excrements, from the alimentary canal. A similar caution may be applied, with still more force, to that sub- stitution of hydro-carbon or fat, for hydrate of carbon or KOT MATTER OF CALCULATION. 419 starch and sugar, which some authors have regarded as so easy and natural an exchange. For these substances are not by any means convertible or interchangeable in a scale of diet. The cell-wall of the adipose tissue is dis- solved with great difficulty ; its liberated contents are next absorbed in but small quantities; and they then pass through glands which apparently have a long and complex operation to execute upon them, before they are admitted into the general circulating current of the blood. And, lastly, a contrast of the results of their final combustive metamorphosis with those of the combustion of the hydrates of carbon, shows* that they require the combination of a much larger quantity of oxygen, before they can leave the body in the form of carbonic acid and water. The total amount of food required by the body is also exposed to circumstances which are just as certain to baffle ^11 such calculations. For this important quantity will evidently vary with the rate of waste sustained by each individual : — and hence with the activity of his life; the nature of his habitual exertion ; and the state of his mind ; * Assuming the equivalent proportions of hydrogen and oxygen present in fat and sugar to be got rid of as water, during the combustion of both these substances within the organism, the former (see note to p. 33) leaves 88 -3, the latter (C 12 H 12 12 -12HO = C 12 = ^ = ) 40, per cent, of its original mass for oxidation. The equivalents of oxygen required for this process in the two cases respectively, amount in round numbers to 445 and 107. In other words, equal quantities of fat and of sugar demand for their com- bustion, the first about four times its own weight of oxygen, the second about one-fourth of this proportion, or its own weight only. And on Du- long's estimates already (p. 33) noticed, we may calculate that, while the combustion of 100 grains of fat would evolve about 59,520 units of heat, that of 100 grains of sugar would liberate only 18,570, or less than one- third of the heat given out by an equal weight of fat. BE 2 420 CHOICE OF FOOD. OR DIET. as well as with the climate, race, temperament, and educa- tion, which help to form the microcosm of every man's personality. The range in the necessary quantity which these circumstances may produce, cannot be specified with exactness. But the influence of some of them (and these by no means the most potent) may be well illustrated by a comparison of the habits of the various members of a single family, or other group of persons : the ration barely sufficient to support one in health, constituting, for an- other, a large superfluity beyond what he or she can | sibly consume.* Hence the true value of Physiological Chemistry, in respect to the principles of Dietetics, is that of I admirable guide to the general coi ion of a pr food. In this capacity, it is not too much to Bay that its veto ought to be absolute. But this negative function U almost the limit of its practical usefulness. Our cl the exact quantities and qualities of alimentary which are necessary to construct a pi may indeed be sometimes explained by Chemistry. But it * It is thus no argument against either the economy or the nc a given Dietary, that a certain proportion of (hoc a it is intended find it more than tl. I through. That soldiers habitual! of their rations, or prisoners leave quantities place of confinement, may indeed s me inquiries: amor. mer, as to their temperance. and plaoi le; among the latter, as to the nature and amount of work t' apart from the considerations alluded to in the obvious that a sufficiency for the many must be a superfluity for tin I that the administration of a due supply of food by the doling out of ra*i implies such an appearance of waste; the absence of which woul more suspicious than its presence. AVERAGE QUANTITY OF FOOD. 421 must always be dictated by experience. And the Dietaries of Gaols, Workhouses, and other public Institutions, cor- rected, as they have so often been, by the ghastly hand of Death himself, have fixed the limits of the food necessary for health, with an accuracy which, considering the price of human life that has been paid for it, ought surely to satisfy the most rigid Economist. From such sources of information we may deduce that, in this climate, a healthy adult male, of active habits, re- quires daily about two pounds of solid food. Of this food, six or eight ounces are preferably meat. While, if the quality of such a diet be lowered (as, for example, by the introduction of much Potatoes or Rice), its quantity ought to be increased, so as to compensate for this lessening of its nutritious characters. Bat if Diets should be judged of by experience, it is no hasty or superficial observation which entitles us to appraise the various scales of food adopted by persons or Institu- tions as the means of nourishment. On the contrary, the action of food is, for the ignorant and unthinking, a scarcely less perilous question than that other and cog- nate question concerning the influence of Medicines, which is (and probably always will be) the very touchstone of Quackery, both within and without the pale of the Medical profession. Hunger and leanness, for instance, are vulgarly regarded as the chief results of an habitually insufficient food. Muscular and mental weakness would probably be added to these effects by all those who had ever really experienced such a deficiency. But Physiological Medicine takes a far E E 3 422 CHOICE OF FOOD. OR DIET. more sweeping objection to an insufficient nourishment : and points out infinitely more delicate, as well as dangerous effects, almost too numerous to mention. Dysentery, scurvy, scrofula, ulcers, phthisis, gout, rheumatism, and a host of the worst ills that flesh is heir to, are thus traced by science to a meagre Dietary; and that, too, with a precision and conclusiveness such as, in the name of hu- manity, forbids all further experimentation in aid of the frightfully numerous observations of this kind which the casualties of human life, and the ignorance and cup: of individuals and governing bodies, have together - forded. Diseases, again, are foreseen by her in their preliminary stage of cachexia ; to be kept at bay by richer food. And even "common expea and "comi justice" are occasional! . The one, for example, finds that a scanty or innutrit: patible with a not very unhealthy 8 ace oft!, use it. The other inveighfl sandal of a cri- minal in prison being better fed than an honest Labourer out of doors. But Phy — somewhat to mo- dify the warning of th< Id Greek — to call no man healthy till he is dead : in other words, not mere!} to the absence of disease at the moment, but to trace out the slower and more permanent effects of a Dietary in i life, before we call it a wholesome one. The workL child, stunted and weakly through its whole nee, or failing for want of stamina in some casual the sturdy r hammed dying out long before the period of English old age : the field labourer crippled with the premature decrepitude of rheumatism : the prisoner, TEST OF ITS EFFICIENCY. 423 released from his cell to languish as a blanched and re- laxed specimen of humanity, unfit for all active exertion, through the remainder of his days : these and a hundred other similar illustrations might be adduced, to show how little the mere absence of immediate disease disproves the insufficiency of a diet, and the loss of health or life which it ultimately brings about. Most of these illustrations, however, might be challenged as offering but doubtful examples of the exclusive effects of too sparing a food. Indeed, in all of them the defi- ciency is relative, not absolute. Neglect, overwork, ex- posure, and confinement, not only count for much in the above four hypothetical cases respectively ; but are, in the main, precisely those circumstances which imperiously de- mand a richer and larger food. And they thus permit us to deduce two chief propositions, which all our existing know- ledge of Dietaries does but tend to confirm and illustrate. The first is, that only that Diet can be regarded as a good one, which observation shows to be capable of preserving health, from the commencement of independent nourish- ment in the young animal, to the natural decay which marks the extreme period of old age. The second — that while it is very doubtful whether such a Diet has ever been explicitly recognised and adopted by any human society, it is certain that the mixture and variety of food commonly made use of is, in the main, both natural and useful : especially in its conditionating the prescribed func- tions of the human race. Permitting changes of climate, protecting against the agencies of injury and disease, nerving to exertions otherwise impossible, a wide range E E 4 424 CHOICE OF FOOD, OR DIET. of food is practically essential to Man : to whom, humanly speaking, it would have been impossible to replenish the earth and subdue it, or to have dominion over its brute inhabitants, unless, with this command, he had also received a sanction to range its various organised materials for his sustenance. Hence there is hardly any circumstance of life or habits which does not in some degree influence, and so far dictate, the choice of food of him whom it affects. And con- versely, there is hardly any injurious influence which the Dietary of the individual may n< m >r a amterpoise. Bruises, dislocations, and fractures arc no « rule: either as regards the vigour of p rception and m< mentby which they would often be avoided; orthediffei degrees of mechanical force requisite to produce a given lesion of either kind in well and ill-nourished tissues re- spectively; or the different facility with which they would repair these injuries. And of course the same rules are traceable in the causation of 1' dy in t: maladies notoriously ascribable to the food, but in others in which the dietary plays but a secondary and often ob- scure part. The hearty well-fed English miner i-, I as regards his capacity for work, and his liability to disease, so marked a contrast to the miner of Germany, that his privation of light and air might well i an unphilosophical observer, almost matter- of indifference. The process of poisoning by lead is. as is well known to artisans much exposed to the emanations of this metal, greatly impeded by a rich and fatty diet. Indeed, experi- mental Physiology acquaints us with what is a more strik AS GUIDED BY PHYSIOLOGY. 425 (because more exact) illustration of these rules ; lacking scarcely anything which can make it an " experimentum cruris" The large and valuable materials of the bile can, it seems, be lost to the system with something approaching to impunity, if ooly the loss be compensated by an equi- valent increase of the food. While, without such a coun- terpoise, the discharge of this secretion through an artificial fistula speedily brings about the death of the animal. (Compare p. 195.) But the Physiology of food not merely registers the deductions of experience, and confirms the dictates of instinct, with respect to Diet. It groups our facts by ex- planations, which often claim the accuracy and the rank of theories. It checks the deceptive assertions of hasty ob- servation ; warns us against the still more deceptive boun- dary which separates the claims of instinct from the cravings of luxury; nay more, as already hinted, exposes stupidity or cruelty cruising under the colours of philan- thropy. It further questions the dietetic practices of Physic ; which, fluctuating more than Physiology in obedience to the fashion of the day, precisely because the emergencies of disease perpetually import into its discussion the strong feelings, and weak judgment, of an uninformed public, must be content to be judged of, as a scientific edifice, in some respects by the harmony and solidity of its union with this, its natural basis. On all of these grounds it may be advisable briefly to review a few of the chief cir- cumstances, which, on rational principles, require adjust- ments of Diet. 426 CHOICE OF FOOD, OR DIET. Age, in its extremes of infancy and decrepitude, may be first noticed. As respects infancy, there is little need of asserting the importance of milk — as the only proper food — to the newly born infant : or even of deducing, from the wide chemical deviations of this secretion in different species and individuals, as well as periods of lactation, the general advisability of the milk which should form the only nutriment being that of the mother herself. It is chiefly during that period of early childhood which foil weaning that any dietetic questions can really arise, such as Physiology can help to answer. The peculiar wants of a child, etfl regards its food, may be best recollected and explained by the peculiarities oi Nutrition generally. Compared with the adult. i1 up, in a more or less permanent form, a far pro- portion of the constituents of its mgesta amqng th< of its body. In other words, for equal amounts of (though not of bodily* Bubstance also ), a Bmaller quantity * Exact observations, on this and other points allied to it. i our disposal. But it is more than probable that the vital organism of the young animal involves both a larger supply, and a I waste of its tissues; as represented, for instance, either by tin- i their total interchange, or by the fraction of their i time. Thus we may estimate that a child of eight or nine ge, as contrasted with a full-grown adult, actually gives off. relatively to the v. of its body, one and a half times as much carbonic acid ; and the same rule probably applies to its urea. But neither of ions invali the above conclusion, which rests indeed on the m f increment or growth (eomp. p. 2). as proving a preponderance of incom .; endi- ture. The degree which such preponderance of income over expenditure may attain in the independent Nutrition of the young of the V class, is well illustrated by the growth of the Salmon. According to Major Keane ("Times." April '22. 1861), the Smolt of three ounces in April IN CHILDHOOD. 427 of effete matter is necessarily dismissed from its body by those various functions of which the egesta are the ultimate products. Now most of these functions are so strictly depu- rative ; indeed, are so specifically the means of eliminating poisons casually mixed with the ingesta ; that this contrast sufficiently explains why purity from such admixture is in the case of the infant a far more imperious requirement than in the adult ; who receives and assimilates with im- punity, and even advantage, many articles of food which would injure (i. e. poison) the infant. Furthermore, a careful consideration of the processes which we sum up by the term " Digestion," would show that not only are the various metamorphoses thus comprehended conducted more feebly and imperfectly in the infant, but that there are grounds for supposing these conversions themselves to be chemically somewhat more limited. On the other hand, the child requires, for the construction of its future tissues, many ingredients — and that, too, in large quantities — which are little or not at all demanded for that equation of income and expenditure which represents the process of Nutrition in the adult. The morphological and chemical changes, for example, which transform the cartilaginous femur of the infant into the bone bearing the same name in the adult, imply such large and incessant demands on the part of its organism for lime, magnesia, and phosphoric acid, as may well suggest the possible magnitude of the con- trast in the proportions of these inorganic substances re- has been recaptured three months later, in the form of a Grilse weighing five or six pounds, an increase at the rate of 36| per cent, of its own weight daily. 428 CHOICE OF FOOD, OR DIET. quired to be present in its food. Xor does the circumstance, that such a contrast is probably only quantitative, much affect the deducible result. Thus, then, the child requires, on every ground, a food which is purer, richer, simpler, and more digestible than that of the adult. More digestible, both in the sense of being less charged with insoluble matters, and involved in fewer physical obstacles to this process ; and also in the sense of being less dissimilar to the various tissues which it has to form. Eicher, in the true and natural sense of variety of ingredients, mineral as well as organic : a va- riety which civilisation (culture of vegetables, breeding and feeding of animals, and silver-spoon cookery) must rather prevent than favour. Simpler, too ; for richness of this kind is so perfectly compatible with the strictest simplicity, that home-made wheaten-bread, milk, butter, sugar, and a sparing quantity of well-cooked meat or strong broth, would together make up a food such as would be a model of both qualities. Purer, again, in all that makes real purity. Tainted meat, diseased or decayed and other impurities of this kind, seem to tell first and most on the children of the unhappy individuals or - - cieties who are forced to feed upon them : much as alcohol, opium, or the poisonous emanations from living and dead bodies, would, eater is paribus, generally affect them first. Indeed, here as elsewhere, our habits and conduct are tested by our children : who, if not sacrificed to MolochJ as of yore, are at any rate, in another and far more fatal sense, passed through the fires we kindle by our own ignorance and folly. IN OLD AGE. 429 Two considerations only call for further mention in this cursory sketch. The first is, that, during the period of childhood, instinct is a better guide — at any rate, a more determinable one — than at later ages ; when habits and taste, often artificial, are so easily mistaken for it. The second (which constitutes almost a corollary to the fore- going) is, that the concurrence of a feebler digestion, with greater systemic wants ; or of a kind of comparative inability on the part of the alimentary canal, with those greater constitutional demands of which the more frequent craving for food at this age is a natural expression ; con- stitutes a peculiarity of the child's Nutrition, requiring to be met by a proper adjustment of its meals : which, to fulfil these somewhat opposite demands, ought to be both smaller and more frequent than would be generally re- quisite in the case of a healthy adult. Old age, though it reverses many of the nutritional peculiarities of the infant, yet permits no correspondingly simple modifications in the quality and quantity of food. The aged person, it is true, requires less food to replace his diminished daily waste, or the slower and smaller expenditure which represents his rate of Life. His enfeebled organs of Digestion, again, can no longer pre- pare and convert that amount of materials which they formerly elaborated : — materials which, even supposing them thus converted and assimilated, his various functions could no longer use to the advantage of his organism, and finally dismiss from his body. And it is evident that, inasmuch as Digestion, like all other functions, implies wear and tear ; and claims, from a variety of organs, an 430 CHOICE OF FOOD, OB DIET. expenditure of force which is tantamount to an expen- diture of tissue ; any undue claims upon such expenditure can but weaken, rather than strengthen, the failing frame. Furthermore, those large fluctuations in the quantity of blood distributed to the digestive organs, which are ob- viously necessary for their operations, must, if unduly favoured and exalted, add to those risks of vascular lesion, which all trustworthy statistics show to be a large element, and frequent occasion, of death in old age. Hence, on all these grounds, moderation in the quantity of food, care in its preparation, and simplicity in its form, are the principal requirements in the Dietary of the aged. But, on the other hand, we have to recollect the com- plexity, and therefore the difficulty (and even danger) of all generalisations as to the alimentation of advanced life. The habits of a life-time are, indeed, often as thoroughly built up into the mind and body of the individual, as though they were literally incorporate with his tissues. Idiosyncrasies, it may be, confirmed and exaggerated by custom : poisons almost disarmed by habit : diseases or degenerations claiming their own special treatment, both as to Diet and drugs: — these, and a host of similar con- siderations, familiar to the practitioner of Physic, modify (and often reverse) all ordinary rules for the food of old ao-e : or reduce them to such truisms as are devoid of all specific or casual meaning. Excess, for instance, we may truly say, is in the old unusually injurious. But how to define excess ? Reduction of diet may be advisable. But how far shall this reduction go ? The successes of unusual abstinence (like the fulfilments of presentiments) are IN THE FEMALE. 431 bruited abroad by the friends of the resolute septuagen- arian. But who registers its failures? Certainly, to judge by experience, a healthy old age is rarely extorted from Nature by rash innovations in the decline of life. Sex, as modifying food, has a double import. The smaller amount of bodily fatigue and exposure which ought to be the lot of the female, would of course demand a somewhat smaller ration of food to correspond with the smaller resulting waste of her bodily tissues. This feature of her Nutrition, however (to which there are so many exceptions even in civilised societies, that we may term it, only too truly, a casualty of the female in respect of diet), is greatly outweighed by another, more specific to the share taken by her in the function of reproduction. Her nutritional Life may indeed be regarded as offering some analogies to that of the child. That continual deposit of new materials, in the form of an increase of all the tissues, which constitutes the growth of the child, is paral- leled in the female by the development, and subsequently the lactation, of her offspring. Hence, while in the adult female, as contrasted with the male, there is a much scantier process of waste, as shown by all the numerical phenomena of excretion *; in both the child and the female, the balance of Nutrition so far inclines from an exact counterpoise, as to permit such a constant surplusage * It may be estimated that, in the female, a given weight of bodily sub- stance gives off about five-sixths the amounts of urea and carbonic acid given off by a similar weight in the male. Pregnancy raises this five- sixths to about eleven-twelfths. And the close of the epoch of fertility seems almost to equalise the previous difference of the two sexes in this respect. 432 CHOICE OF FOOD, OR DIET. of ingesta over egesta, as can be devoted to other pur- poses than those of the mere maintenance of the existing body. But while the growth of the child is continuous, the reproduction of the female is necessarily more inter- mittent. And hence this surplus, when not otherwise claimed, appears as a periodic haemorrhage from the same organs which, during gestation, appropriate it to the ex- penditure of their own function for the purpose of re- production. From the many plrysiological deductions suggested by this brief statement, one only may be selected from its important influence on the subject of Diet. Great as are the fluctuations of Nutrition in the female during the age of child-bearing, it is clear that they are provided for, rather by causes intrinsic to her organism, than by any correspondingly large and rapid extrinsic changes in the quantity and quality of her food. In other words, preg- nancy and lactation no more demand systematic high feeding, than do virginity or sterility claim a converse process of comparative starvation. Analogy, indeed, would suggest, that during those periods of active maternity, when the female is, kclt i^o^?]v, woman, and the con- stitution can no longer relieve itself by a haemorrh* expulsion of what is superfluous or detrimental, but m to some extent inflict a proportion of any such materials on her offspring, her diet should, so far as possible, approach that of the growing child in all those requisites of richness simplicity, purity, quantity, and frequency, above hinted at. And, indeed, instinct and experience concur in re- presenting such a mode of alimentation as best conducing AS INFLUENCED BY HABITS. 433 to the health of both mother and offspring. While many recondite phenomena of these states suggest to the Physio- logist, that the peculiarities of Nutritional life and waste associated with them, are such as distantly resemble that- constitutional reaction which accompanies the inflammatory state ; and are therefore likely, to judge by the presump- tive evidence of this analogy, to render all excess of food or stimulants unusually deleterious. Habits of life affect Diet by influences as many and diverse as this vague but useful phrase would itself suggest. By none, however, more seriously than by those which relate to the amounts of exertion, and of exposure ; and the correlative degrees of waste sustained by the muscles, the brain, the skin, and lungs ; according as an individual is habitually active or slothful; naked or thickly clad ; moving to and fro in a pure fresh air, or confined to an impure atmosphere more or less charged with the emanations of animal life. The influence of confinement of this kind is not merely that which we might expect ; — such a diminution of waste as may be plausibly connected with the accumulation in the organs of its last products (carbonic acid, urea, water, and the like). It is rather some deeper disturbance of Nutrition ; which (unless we explain the greater require- ments of the prisoner by the absence of various volatile ingredients presumably contained in larger proportions in a fresher and freer air), reminds us of the rule already laid down, that confinement, in the main, demands a richer diet. But quite compatible with such a rule is another, of far more frequent applicability : namely, that confinement F F 434 CHOICE OF FOOD, OR DIET. so greatly injures the Digestive powers, that the Dietetic practice ordinarily adopted by the affluent (among whom the consumption of food is limited only by the instinct or discretion of the individual) demands, in the case of the sedentary, so many exceptions and qualifications as to be rarely, if ever, applicable. Often, however, the impairment of the natural appetite indicates with sufficient exactness the decrease of digestive and assimilative power. The varying amounts of exercise usually (but not neces- sarily) connected with exposure and confinement respec- tively, affect Diet by a very simple rule. Up to a certain degree, which may practically be almost taken to represent the amount of habitual exertion compatible with health, muscular action calls for food, and favours its digestion. Beyond this degree, it has precisely the opposite effect ; and its increment rapidly brings on a feverous state, in which all appetite soon fails, and any true Digestion be- comes impossible. In the latter case it is evident that more or less of the waste properly supplied by the food is thrown entirely on the tissues; and (as a corollary to this proposition) that any prolongation of the exertion beyond a certain limit would be impossible. It is probable that the blood is the agent of this singular inversion of the healthy proportion between food and exercise : that the derangement of this fluid, perhaps by an accumulation of the regressive (p. 270) or effete constituents of the mus- cular tissues themselves, unfits it for its office, in con- nection both with Digestion on the one hand, and with the Nutrition of muscle on the other. At any rate, the fact is undoubted, that not only is it impossible to compensate or AS INFLUENCED BY MENTAL EXERTION. 435 sustain undue exertion by a mere increase in the quantity and richness of the food taken, but that the feverous state such exertion soon brings about is best treated by a cor- responding diminution of aliment in both these respects. Indeed, inten^jty and protraction of toil demand, as they increase, a decreasing scale of food, which rapidly sinks to the meagre fare formerly adopted by Couriers while travel- ling day and night. Mental exertion might perhaps be regarded as repeat- ing this rule; only with an earlier limit or climax before the reversal of the natural proportions between food and exercise. Apart from the collateral circumstances of mental toil, there can be no doubt that the wear and tear of nervous energy and tissue which it implies, demand a rich and plentiful food. But collateral influences are often too complex to permit this rule to be carried to its otherwise legitimate conclusions. The want of air, of bodily exertion, of sleep, of change of posture ; the per- petual strain on one or two senses, or even faculties : these, and many other circumstances which readily suggest them- selves, often distort (or even reverse), the results which mere mental exertion, strictly so called*, would bring about. It is perhaps to these that we must attribute much of the injury to Digestion and Nutrition, for which mental exertion is ordinarily held answerable ; and the precautions as to both, which are the practical import of the careful and somewhat restricted Diet proper to the brain-worker. Climate affects food mainly by the temperature it im- * In this stricter sense it "would perhaps be invidious to say that great mental exertion is unconimon ; but it is certainly not often fatal. F F 2 436 CHOICE OF FOOD, OR DIET. plies. And though temperature exercises a general influ- ence, such as can neither be denied nor mistaken : still the circumstances collateral to it, and yet more to the climate with which it is associated, greatly modify all ordinary rules of Diet based upon it. For example, the maintenance of the bodily heat against extreme cold calls for an increase in the products, and therefore in the rate, of the bodily combustion. Hence, an Esquimaux, the air of whose fireless hut varies from 0° to 32° Fahr., and who passes the remainder of his time, sparingly clad, in an atmosphere of 30° to 70° below : consumes about 14lbs. of raw meat daily * : — a quantity of food which would be quite repugnant to all natural instincts, and equally incompatible with health, in a Hindoo or South Sea Islander. But the contrast is equally striking as to quality. One-third of this meat is fat : fat, too, far less diverse in composition, and digestible in physical arrangement, than is the butter largely used by the Hindoo. Nay more, there are ground a that both the fat and muscle of the flesh thus consumed are more potent sustainers of combustion, and under ordinary circumstances would be more indigestible, tl the analogous tissues of the various domestic or wild aui: found in warmer latitude-. What this fat does, and why it is so large an element of Arctic food, are not questions to be answered by any single or hasty speculation. We may take for what it is worth the analogy of the incandescence of fat in a lamp : the large equivalent of heat evolved, and the exceeding ditrl- * Dr. Hayes's Arctic Boat Journey. Bentley: i860. AS INFLUENCED BY COLD CLIMATES. 437 culty of burning up all the carbon. Such an appraise- ment, however, would probably leave us disinclined to overlook two other contingent elements of its value : (1.) the wear and tear of the fatty tissues of the nervous system in the process (whatever be its exact details) of the de- velopment of heat ; and (2.) the physical value (indeed the absolute want) of an outer covering of fat : — a require- ment, which, in these latitudes, man shares with the Quad- ruped, and with the Cetacean. Certainly the experience of our Arctic voyagers is conclusive, both as to the complete inversion of dietetic instinct which the European undergoes in these regions, and its beneficial influence against their inclement climates.* * We may sum up the chief elements of that increase of food, which is required in a cold climate, as follows : — 1. The increased loss of heat from the surface of the body: (a.) by ra- diation, which is unopposed, as in warmer climates, by any converse pro- cess of absorption; and (b.) by convection. In the latter process the par- ticles of air which strike against the body, or against the conducting sub- stances in contact with it, carry with them in their further course a certain portion of its temperature. And this convection is proportionate to the number of aeriform particles thus impinging in a given time ; in other words, to the velocity of their renewal. Hence a high wind at 32° cools the body far more than a still air at 0°. 2. The increased loss of heat from the lungs. Here, again, we may notice two chief constituents : (a.) the heat expended in warming the re- spired air; and (b.) the heat given out, both as sensible and latent, in the watery vapour exhaled. As regards the first, the law which regulates the heating of the air inspired, allows a vast increase in the loss of prdmonary heat, in proportion to the coldness of the air which receives the expired air, even though its absolute temperature remains below the standard of the air exspired in a temperate climate. Thus, according to Valentin, air inspired at 68° is exspired but 31|° hotter; inspired at 21° F., is exspired 68° hotter. In other words, the inspiration of air 47° colder, more than doubles the previous loss of heat by the lungs ; with air still colder, the F F 3 438 CHOICE OF FOOD, OR DIET, On the other hand, a moderate temperature of the sur- rounding air reduces the demands of combustion to those of the organism in general, rather than of the calorific function in particular. And any increase of temperature above this degree tends, directly or indirectly (according as it is above or below the heat of the living tissues), to loss probably increases in a geometrical progression. As regards the second (b.), the water} 7 vapour which is contained in the inspired air, and is scanty in proportion to its coldness, is increased in the lungs by a contribution from the blood present here. This contribution, the quantity of which may be roughly estimated as tending to saturate the air at the temperature of exspiration, robs the body, not only of the heat it carries off in its own temperature, but also of the heat rendered latent by the sage of its water from the liquid to the vapour} 7 form. Th both these sources is necessarily great. Amongst circumstances more collateral to the pulmonary interchange may only notice two, which, though they necessarily exercise a direct in- fluence on temperature, are more important as T >f that process by which all these difficulties are met and overcome. The seantin vapour of a colder air implies, bulk for bulk, a larger proporti gases, including its oxygen. And the general increase of density cj by cold amounts — presuming the capacity of each respiration uochanged — to an increase of oxygen which far transcends this. For example, a dry air / 15 + 62 77 \ at - 15° F. contains ( 480 = ^0 ; auJ 4U3 ' 48 ° * : 5 t0 6 nearl . v ) one " fifth more oxygen than an equal bulk of the same air at 62 c . There are of course other Physiological contingencies of Arctic exist which might easily be brought together to increase this list. But, on the whole, many of these arc doubtful, and all are subordinate to the pre- ceding. That the vast ranges of temperature, the long a and. indeed, the whole of the above phenomena of a highly taxed Nutrition, claim a larger proportion of the total nervous energies than they would demand in more temperate regions ; and hence leave less of these en< to be expended in the direct service of the mind: — is tallies alike with the history of the Hyperborean tribes, and with the sonal experience of those of our brave fellow-countrymen, and our American kinsmen, who have battled successfully for science and humanity in 1 terrible scenes, against all obstacles, mental and bodily. AS INFLUENCED BY HOT CLIMATES. 439 evoke the application of the corresponding safeguard against heat, both in plants and animals ; namely, evaporation. But the difference between the animal and vegetable forms of Life, in the fact that the former does, and the latter (for practical purposes) does not, largely generate heat within its tissues, seems to regulate the degree in which this physical compensation is made use of. In the case of a Palm-tree in a desert, steadily maintaining itself twenty or thirty degrees below the temperature of the surrounding air, the evaporation of the water it ab- sorbs or constructs is the chief, if not the only, explanation of the contrast offered by its living organism. But in the analogous case of a human being maintaining an equal thermometric difference, mere evaporation is not the only interpretation. Any diminution in the evolution of heat within the body would practically have the same effect as a positive reduction of temperature, effected by evapora- tion at the surface. For even where the outer air ' or clothing has a temperature far above 100°, the smallest hypothetic decrease in the evolution of internal heat would permit the same lowering of external temperature to be mediated by a decreased evaporation. The empirical side of the question seems to a great extent explained by these considerations. Experience shows that, as a rule, the food consumed in hot climates is both scantier and less rich than that of colder regions. And even the few exceptions to this rule are sufficiently explained by the foregoing considerations. Increase of muscular exertion must increase the ordinary requirements of a warm climate. And the great contrasts of tempera- F F 4 440 CHOICE OF FOOD, OE DIET. ture which are met with even in hot climates* where a frosty night often succeeds a burning day, may similarly demand a correction of our ideas respecting the thermal characters of a particular region. Again, the cravings of luxury and sensuality are not quite unknown even in Tropical climates : and the difference between what is wanted and what is eaten, or between what is eaten and what is really digested, is doubtless at least as great in the case of many an affluent Asiatic, as of a Western gourmand* But, on the whole, where a great degree of warmth is possessed by the air around, so that the body both gives off less heat, and requires less exercise to aid in maintaining its temperature, the habitual food is reduced in quantity. And its quality is still more affected. A large proportion usually cone of starch, sugar, or the other substances allied to these hydrates of carbon ; which, while they certainly seem to develope less heat by their assimilation, have the further merit of undergoing, if undigested, a decomposition much less hazardous both to the organs of Digestion, and to the body in general, than that which, under similar circum- stances, engages the ordinary ingredients of our animal food. Indeed, to this advantage (which the pathology and treatment of dysentery well illustrate) may probably be added those of a more accurately regulated absorption into the blood, as well as of a readier elimination from it ; points in which excesses of oily or albuminous food seem more liable to damage the constitution, than are those starchy substances which almost every animal seems to take with impunitj^ in any reasonable quantity. The influence of Race upon Diet is at present in com- AS INFLUENCED BY RACE. 441 plete uncertainty. To judge by those contrasts in indivi- duals which society offers us^ as well as by the valuable information which of late years cattle-breeders have placed at our disposal, the frugality of some nations may partially depend on a capacity* for being nourished with smaller quantities of food : a comparison which indeed the fattening of animals of the same species on a very different quantity of food converts into a certainty as regards them. But climate^ habits, mental and bodily toil, and a variety of allied circumstances; generally deprive such contrasts of all practical value in the human subject. * In such a presumable capacity, however, it is probable that there are two elements so diverse as almost to constitute alternatives to each other. In the hardy, frugal person, as well as in the wiry, lean, wild animal, we seem to recognise a tenacious retention, and complete elaboration, of the materials metamorphosed in the various functions. In the small-boned, easily-fattened animal (whose human analogue, by the way, every accurate observer of his fellow-creatures must often have noticed), bred by an arti- ficial selection, a peculiarity precisely the reverse of this seems to obtain. The development and nourishment of tissue, qua tissue, has a very early limit; beyond which all further Nutrition tends, not to a true assimilation, but to an obliteration of the differences characteristic of the several tissues : interspersing muscle, for example, with fatty matters ; and also depositing these substances in enormous quantities over the whole body (comp. pp. 275, 276) ; as well as surcharging the blood and the nutritional fluids to an unnatural richness with albuminous and allied compounds. But the two economies of Nutrition are so far antagonist to each other, as that (for example) an Arab of the Desert would live well on a quality and quantity of food which would destroy an European by its insufficiency. On the other hand, the analogy of the wild, lean, old-fashioned breed of Pigs, as contrasted with the more easily fattened modern breeds, — a contrast which would, under similar circumstances, repeat this proposition, — entitles us to presume that the constitution of the Arab would offer much the same reluctance to fatten, as does that of his brute analogue. In every true sense, of course, Nutrition and "Natural selection" go hand in hand, and the wild animal is physically superior to its more easily fattened congener. 442 CHOICE OF FOOD, OK DIET. Disease influences Diet by requirements so various and important, that nothing short of a treatise on Practical Medicine could fitly discuss this part of our subject. It is not, however, in the form of substantive maladies or lesions that we need here speak of the influence of disease upon the alimentary requirements. It will be enough to allude to some of the chief states or conditions which call for modifications of the food. The involvement of the Digestive organs in disease, naturally ranks first among these states. For whatever the organ or tissue affected, it is evident that the office of the group to which it belongs will always suggest the application of two rules; which, mutatis mutandis, Eational Medicine would probably repeat in reference to the diseases and injuries of every part of the body. Con- sidering that the food constitutes the material an which the digestive organs have to operate on the one hand, and the proper stimulant of its special sensibility on the other, it is evident that the rules of securing for the seat of every lesion the maximum of rest, and the minimum of irritation, would alone guide us to a suitable choice of food. Let us suppose, for example, that an ulcerated state of the stomach is present. Here complete re^t to the di- seased organ is forbidden by the circumstance that its function is so essential to Life, that its complete repose during a period which would elsewhere be sufficient to permit the healing of an ulcer, would ensure the death of the patient. But while, by avoiding -all superfluity of those albuminous constituents which it is the office of the AS INFLUENCED BY DISEASE. 443 stomach to digest, we give it as much rest as we dare ; so, by a proper choice of the quantity and quality of these and other alimentary ingredients, we may render the food not only less irritating, but less exacting, to the stomach. In milk, for example, we have a food of model composi- tion, arranged as a bland homogeneous liquid. Its only faults for this malady — namely a superfluity of protein (p. 56), and a tendency to precipitate in the stomach (p. 291) — are obviated by incorporating it with some pure starchy substance, and boiling both into a thickish pulp. By administering such food in minute and frequent doses, we may avoid all distention of the organ, and per- mit this food to pass out of one end of the stomach almost as rapidly as it enters by the other. Lastly, in great emergencies, the use of enemata offers a temporary means of sustaining Nutrition by the administration of a scanty supply of food, without disturbing the stomach at all. In ulcerative disease of the large intestine, converse principles will apply. The avoidance of irritation, and the diminution of the natural stimulus, are here effected, not only by a restricted quantity and liquid form of food, and especially by the prohibition of all indigestible solids which would physically irritate the mucous membrane while being slowdy pushed along it by the peristalsis of the sub- jacent muscular coat — but by a selection of such food as may contain a minimum of those alimentary ingredients which are most liable to decompose during their natural sojourn in this part of the canal. And, without any direct allusion to the special relation of this and other intestinal 444 CHOICE OF FOOD, OK DIET. maladies to decomposing organic matter (p. 243 ), we may point out that the comparative anatomy of this segment of the canal in Man and various animals, clearly indicates that there is a special and intimate relation between the maximum of its development and function, and the large digestion of vegetable (especially starchy) food. Sustain- ing this kind of food with comparative impunity, as a kind of natural stimulus, — at any rate, as the materials of its special function, — it appears to be far less concerned with the metamorphosis and absorption of the albuminous con- stituents of the food. Hence the spontaneous decompo- sition of these ingredients of the i/ngesta in the ulcerated bowel, unchecked by secretions which (like the gastric juice) should specifically control and prevent this chan and furthered by the admixture of such impure and effete products as those which are poured out by the ulcerated surface, rapidly convert such protein-compounds into sub- stances of a highly irritant — we might almost say poisonous — character. The Diet of those diseases which are less specifically re- lated to the Digestive organs, must be regarded as a more difficult question. The conditions through which alone we can trace any principles of alimentation, remain in some cases doubtful. And even in those instances in which the interest that naturally attaches to the more common and dangerous of our various maladies has led to close and extensive observations, there is still a re- markable contrariety in the conclusions arrived at different persons. Thus the rule — that Diet should be rich and tolerably AS INFLUENCED BY DISEASE. 445 copious in all diseases of exhaustion, scanty and simple in all diseases of repletion — is one which many would un- hesitatingly subscribe to, as founded on instinct, echoed by reason, and confirmed by experience. Nevertheless the present day has shown us some eminent professional au- thorities, who have almost seemed to question whether there are any diseases of repletion at all ; whether, in short, the vast majority of maladies do not either imply, or pro- duce, such states of prostration and exhaustion as im- peratively require the administration of large quantities of food, and even still larger quantities of some powerful alcoholic stimulant. It is perhaps humiliating to own that Medicine is still discussing such broad and obvious propositions as those involved in the resuscitated Erunonian views just hinted at. But it is useless to disguise the fact that such dis- sensions exist. And it may not be superfluous to assert that, after all, a good deal of truth will probably be found to have been embodied in those older notions with respect to constitutional states as influencing Diet, which the Physiology of the last century thought itself warranted in asserting ; and which even the Microscope has scarcely yet disproved. Eepletion, for example, is a state of the constitution respecting which one can hardly doubt, both that it actually occurs, and that it demands a correlative Diet. Sometimes plainly recog- nisable as a kind of diathesis ; at any rate as a constitu- tional state unattended by discernible local lesions * ; * A prize Pig or an over-fed Spaniel would well illustrate this state, and might even suggest its appropriate treatment. 446 CHOICE OF FOOD, OR DIET. oftener seen as the premonitory stage of gout and equally characteristic diseases ; it is impossible either to ignore, or to explain away, its general and independent manifesta- tions. Nor are those casual effects by which it often ex- ercises an important influence when intercurrent to the phenomena of other diseases, less dangerous or charac- teristic. It seems impossible to doubt that a casual ple- thora, substantially amounting to (and felt by the patient as) an excess of blood and vigour, may kill, by inducing haemorrhage into a diseased brain or lung ; or may 1 »e re- lieved or staved off by a bleeding from the nose, by ve- nesection, purging, or even low diet. And, conversely, it is difficult to imagine that alcoholic stimulation and high feeding can generally be otherwise than hurtful and dangerous in plethoric states of this kind. Of course we are here evading all question as to the constitutional states which originate the tubercles oc- casioning such an haemoptysis ; and the decayed and de- generate condition of those cerebral vessels, whose rupture gives vent to a haemorrhage into the nervous pulp. But this we have a perfect right to do. For though it is true that the plethoric fulness which we claim to observe, is sometimes only the conditionating cause of the fatal out- break, or the last disturbance of health which precedes the lesion of tissue, still this subordinate import no way affects the question of its existence ; and is often quite as in- sufficient to reverse the indications of its treatment. But modern Physiology and Pathology, have. I conceive, afforded us something more than a mere confirmation of what Medicine seemed to have deduced, both from reason AS IXFLUENCED BY DISEASE. 447 and experience, relatively to the perils of repletion, and the advantages of a judicious reduction of this state by an appropriate reduction of the ingesta. They have given us the details of this condition in respect to various im- portant organs ; and have shown how various healthy func- tions, essentially of a depurative character, are capable of being checked by Disease. The presence of an excess of the materials which are thus prevented from undergoing due elimination, gives rise to various states, more or less akin to repletion ; states which, however partial, are of ex- treme importance, from the poisoning which any large excess of such impurities — as in the case of the liver or kidney — virtually implies. And there can be little doubt, that a more general repletion ; a stagnation or congestion of the blood, as a whole, behind the diseased organ ; is often added to the foregoing. And that, in conditions like these, it is important to avoid all overloading of the blood by the introduction of superfluous new materials from without ; nay more, that, so far as is safe or possible, it is advisable to rest the diseased organs, by reducing the materials on which they exercise their depurative func- tion — this would seem to be the correct general principle of diet respecting them. For example, in many cases of bronchitis, jaundice, or renal degeneration, a plain nu- tritious food, in sparing quantities, and unaccompanied by all alcoholic stimulants save those required by unusual complications, would best fulfil this indication. In the main, Nature herself enunciates these rules, by the loathing which food under such circumstances excites ; as well as by the scanty Digestion and Assimilation which 448 CHOICE OF FOOD, OE DIET. are doubtless the internal counterparts of this external symptom. But such an instinctive aversion can scarcely be trusted to with safety ; inasmuch as it would often be extended to many articles of food, and protracted over a period of time, to which it would not strictly apply : and might thus protract the illness, if not endanger the safety, of the patient. To choose the right food, and give it at the right time, is a task in which the skill of the Physician has often to anticipate or guide the current of the patient's wishes, with the happiest results. In all cases, a thorough study of the particular mala is of extreme importance. The succession of sympt which constitute a given form of fever, their ordinary du- ration and modifications in any particular epidemic, and even the termination they usually affect, constitute Patho- logical details which are just as influential with respect to the Diet, as to the drugs, required for the patient*.- cure. But though all these propositions are so well known to the Profession, and have been so often stated, that some may wonder at their repetition in a Treatise like this, it may he seriously doubted whether the practice prevalent in the present day recognises such dietetic rules with a distinct- ness such as dispenses with their further enforcement. If there were no such thing as a routine administration of brandy and other alcoholic stimulants in fever : if the cir- cumstances which respectively demand and forbid their use were generally accepted and acted upon : their con- sideration might perhaps be left altogether to the Thera- peutics of Disease, rather than insufficiently glanced at in an Introduction to Diet. But as it is, justice to FOOD AXD STIMULANTS IN FEVEK. 449 Medicine (or rather to human Life) renders it impossible to withhold all opinion respecting a grave dietetic error of the day. We may grants for example, that in many instances of severe typhoid fever, whatever enables the parched and wasted organism of the patient to tide over the period ordinarily limiting the course of the malady, conduces to his recovery; and that, in this way, strong beef-tea 4 brandy, wine, and other nutritious and stimulating sub- stances requiring little change but absorption prior to their action on the body, may be given both as drinks and enemata, with the happy result of saving life. It must be granted, too, that when they are thus administered, the feverous state often decreases, instead of increasing, under their use. We may nevertheless notice one or two features of the existing practice of stimulation, suggesting great doubts of its propriety. To find the drunkard and the abstemious, the young and old, placed on equal (or nearly equal) rations of alcohol — a drug whose action is not merely violent, but is exceedingly diverse in the cir- cumstances thus hinted at, — may well excite the suspi- cion of a dangerous routine ; which, adopted in the pre- sence of those learning their Profession, can hardly fail to give them that low estimate of diagnosis and treatment which the wielding of a single fancied specific almost un- avoidably imparts. To see the typhus which ends on or before the ninth day by cerebral stupor attended with every sign and symptoms of the extremest congestion, treated by large and frequent doses of alcohol, provokes still graver doubts ; nay, to speak candidly, convicts the g a 450 CHOICE OF FOOD, OR DIET. practice of no less irrationalism than danger. And lastly, to find that it is used in most cases, as well mild as severe, suggests analogous conclusions. I have for many years been convinced that, in the less severe examples of both typhus and typhoid, alcoholic stimulation is not only useless, but positively hurtful ; that it keeps up the fever- ous state, retards convalescence, and increases suffering ; and this probably by interfering with that process of the metamorphosis and elimination (p. 461) of a poison, which the whole phenomena of these fevers seem to suggest. And although the time has not vet come for a rational (as contrasted with an empirical) appraisement of the vir- tues of alcohol in disease; although it is still to the equivocal teachings of experience, checked only by a comparison of the physiological effects of the drug with the natural history of the particular malady, that we must exclusively appeal for a decision ; yet the materials aire at our disposal for such a decision si some hi which perhaps foreshadow more definite rules for our judgment. The specific effect of this drug on the nervous system, seems the key to its usefulness : and the casual condition of this organ, the fact which recommends or for- bids its administration in any variety or instance of dis- ease. The dose which rouses the exhausted brain of a feverous patient, and the dram which goads to frenzy the unmanageable circulation of a cerebral cicatrix — whether that cicatrix be the result of a wound from without, or of the effusion from inflamed or ruptured blood-vessels from within — alike illustrate this rule : as indeed would the coma which, as the maximum (or rather sequence") of this STDIULAXTS IN DISEASE. 451 effect, would be observed, under similar circumstances, as the result of doses of alcohol equally diverse in their quantity. It is at least a negative merit of such a view, that its apparent simplicity is not likely to give rise to any dan- gerous or inaccurate routine of practice. On the con- traiy, it has the advantage of calling the most explicit attention to what is after all, in one form or another, the chief difficulty in deciding upon the administration of alcoholic and allied stimulants in various maladies. To distinguish between what will rouse, and what oppress, the nervous centre ; to decide whether alcohol will excite the brain to activity, or failing this, increase its oppression ; whether aether will stimulate the exhausted lungs to re- lieve themselves by an increased effort, or will only pros- trate them by increasing a task already disproportionate to their powers — this problem, the precise elements for the calculation of which are never alike in any two cases, and the practical answer to which no rules will ever enable our Profession to decide, is at least illustrated, as regards these alternatives, by the physiological action of alcohol. Nor is it too much to say that, in some instances, the two effects — the beneficial stimulation of the organ, and the hurtful accumulation of materials for its elimination — are so far likely to follow each other, as that we are compelled to balance the threats of the future against the promises of the present. It is sometimes difficult to persuade a patient struggling with a paroxysm of cardiac or pul- monary dyspnoea, that the aether which suddenly relieves him, may yet be doing him more harm than good. But G G 2 452 CHOICE OF FOOD, OR DIET. it is impossible to doubt, either that this is occasionally the case, or that the fact that it is so often constitutes one of the very gravest responsibilities of the Physician in pre- scribing such stimulants. However this may be, there is one rule in the adminis- tration of these stimulants, which most Physicians would probably agree in ; and that is, the importance which fre- quently attaches to our obtaining the maximum amount and uniformity of exciting effect, in conjunction with the minimum of reaction and oppression in the organ sti- mulated. This object is evidently best attained by a great frequency, and (within certain limits) large dilution, of the dose; which may be thus limited to a small ab- solute quantity. Elimination is always a work of time; and, under circumstances otherwise equal, appears ta proceed at a tolerably uniform rate. And the sudden ingestion of a large dose is not only attended by great uncertainty as respects the exact time and degree of its absorption, and therefore of its direct effect ; but is calcu- lated to give rise to a dangerous reaction, in which an undue excitement is soon followed by a still more perilous exhaustion. One more suggestion, which applies to the administration of both food and stimulants in severe diseases, may conclude this cursory sketch. The varieties of constitutional pros- tration, which may be regarded as impeding secretion, and preventing Digestion, mainly in proportion to their inten- sity; agree in dictating the avoidance, as much as possible, of all ingesta demanding this process, on the one hand; and of all substances themselves liable to rapid deeom- AS INFLUENCED BY CONVALESCENCE. 453 position, on the other. Hence beef-tea is generally pre- ferable to milk ; dilute spirits to wine, and still more to beer; starchy food is often objectionable; and solid pro- teinous substances are still more injurious. On the other hand, the convalescence, from acute illness, of a person previously healthy, will in most cases rapidly reverse these rules ; and indeed may be said in some sense to call for an enforcement of the very same rules as those applicable to the Diet of childhood. Just as, to the feelings of the convalescent, the days of his youth seem renewed, and a keen appreciation of every object of sense around him soon effaces the recollections of the long agony of his illness ; so as regards his Nutrition, an abundant appetite, and a rapid power of assimilation, perpetually claim his digestive function; and unless this be overladen by some casual excess or imprudence, soon build up his wasted organism to its pristine bulk and vigour. G G 3 APPENDIX. APPENDIX A. — * — VOMITING.* " Vomiting, the next symptom of gastric derangement, is an act so closely connected with the healthy organisation of the stomach (indeed so definite a constituent of the Digestive process in many Vertebrata), that onr cursory view of the physiology of the stomach would have been incomplete, without such a brief description of its nature and mechanism as may be usefully re- called here. " Normally, the human stomach propels its contents onwards into the duodenum. But, under various abnormal circumstances, this direction is reversed, so that the gastric contents take a back- ward course through the oesophagus, re-enter the mouth, and are thence expelled the body. Such a reversal obtains in the acts of eructation, regurgitation, and vomiting. And these three acts, whatever their differences of detail, further agree in the conditions of their occurrence, in so far that they all require (1.) an open cardia ; (2.) a closed pylorus ; and (3.) a compressed stomach ; — compressed, that is, either by its own muscular contractions, or by some extrinsic pressure. " In eructation or belching, part of the gaseous content of the stomach is expelled from the mouth. How the cardia becomes patulous, it is not easy to decide. The stomach so frequently * From the Author's Treatise on " Diseases of the Stomach/' pp. 55 — 65. G G 4 456 APPENDIX A. contains gases, and (as may be "well seen in vivisections) the cardia resists their expulsion so efficiently, that we can scarcely suppose this aperture would be opened by the mere evolution of any quantity of aeriform fluid in the stomach ; or would allow of any considerable leakage, save by a definite relaxation of its walls. The agents of the expulsive act are also somewhat doubtful. For though the act appears to coincide with an expiratory effort, and sometimes with even a closure of the glottis, yet the abdominal pressure thus brought to bear on the stomach is certainly by no means violent. But such mobile fluids would scarcely require any remarkable effort for their expulsion. Indeed, tli<<^e con- tractions of the stomach which are necessarily present when the act of eructation occurs during gastric digestion, appear quite sufficient to commence, if not to complete, the expulsion of _ from the organ.* " In regurgitation^ some of the liquid contents of the stomach are returned into the mouth. Thifi accidental complication of the preceding, u -mall quantity uf liquid being carried up the oesophagus together with an ernetati gaseous fluid. In other instances, however, the liquid arises al and so quietly, that it is only perceived when it reaches the ft and back of the tongue, where it- taste causes it It is probable that the nature of this expulsion is closely akin to that of eructation : the abdominal pressure playing, if anything, a still more subordinate part. " The act of vomiting differs from the two preceding, not only in the quantity and quality of the matters (solid as well as liquid ) * In voluntary eructation, a kind of twitch, quite unlike ordinary deglu- tition, introduces air from the pharynx into the upper end of the cesop 1 whence it appears to he propelled into the stomach. Soon alter it r. . this organ, it seems to he returned through the still patulous cardia well-marked expiratory or abdominal pressure ; during which the glottis appears to he at least partially closed. And as the air thus artificially in- troduced into the stomach is often accompanied in its expulsion by part of the gases previously contained in the organ, the voluntary and invok: forms of eructation almost mertre into each other. APPENDIX A. 457 which it expels from the stomach, and in the far greater energy and completeness of the expulsive efforts, but also in the fact — that a violent pressure, extrinsic to the organ, is the chief agent of the process. " As respects this abdominal pressure, it will be remembered that, in ordinary respiration, the viscera of the belly sustain but a moderate compression. For, during inspiration, the contraction and descent of the diaphragm exactly coincide with a relaxation of the muscular walls of the abdomen : while, during exspiration, the compression which these exercise is neutralised by the re- cession or ascent of the now relaxed diaphragm into the thorax. Hence the movable contents of the belly escape all violent pres- sure ; and merely transfer, as it were, a slight force from the upper to the anterior wall of this cavity, and conversely. But if, while the diaphragm remains depressed and contracted, the ab- dominal muscles also contract vigorously, the whole force of either of these two muscular strata may be regarded as compress- ing the viscera within the abdominal cavity. And since many of these viscera are hollow organs, enclosing movable contents, and communicating with the exterior of the body, such a forcible pressure must expel their contents, so soon as their terminal orifices are thrown open — whether by relaxing, or by yielding to a superior force. In this way the abdominal pressure plays an important part, not only in vomiting, but also in defalcation, mic- turition, and parturition ; — affording a powerful, though inter- mittent, force, in aid of those more continuous expulsive contrac- tions which are effected by the muscular walls of the rectum, the bladder, and the uterus respectively. 11 There is ample evidence that the act of vomiting is effected mainly by this abdominal pressure ; which is not only indispen- sable to it, but (as proved by vivisections) suffices to effect it when reduced to a contraction of the diaphragm, or of the abdo- minal muscles, or even to a slight muscular compression of the hypochondria. " The exact aid given by the contraction of the stomach is less capable of determination. That any such assistance not only 458 APPEXDIX A. can be, but often is, altogether dispensed with, it is scarcely possible to doubt. But, on the other hand, it seems equally cer- tain that the abdominal pressure, to which the act of vomiting is chiefly attributable, is often accompanied, and assisted, by a contraction of the muscular wall of the stomach itself. And as might be expected, observation on Man and animals during life shows that this contraction specially engages, not only the py- loric valve, but the neighbouring muscular pyloric extremity of the organ ; in movements which are probably rhythmic (con- traction alternating with relaxation), and peristaltic *, and which there is certainly no sufficient ground for supposing to be c anti-peristaltic. " The phenomena of the act itself quite confirm the conclusions, as to its strictly co-ordinate nature and ar Qt, arrived at by the physiological inquiry just summed up. Feelings of un- easino.% pain, or i a in the gastric - | -re- cede an increased flow of saliva, and a loathing 1. which soon heightens into downright nausea. To th symp- toms accede others of a cerebral import: giddi:. dimness of sight, or even headache. Next occur ret . rhich seem to open tin :id cardia, but not t< :.ded with any abdominal ] and which often hav :t of gradually distending the stomach with air, so as to facilitate the subsequent occurrence o{ vomiting. Finally, an uncontrolL impulse completely cbang action of the muscles of piration, and brings into one moment two contractions, which usually alternate with each other. An energetic closure of the glottis follows the descent of the diaphragm, so that this muscular * Assuming the analogy of this contraction to that verified by Dr. B mont in the human subject, and by myself in the Dog, during the active ^tage of gastric digestion — the rate of pen .1 the alterna- tion of contraction with relaxation, would not be at all incompatil constriction of the whole pyloric B8 st a : which would more than cover the time actually occupied by any - pulsive act during the ordinary fit of vomiting. C lb. Suet - - - - - | lb. Plums - .-- 1$ lb. fl Mustard Biscuit Tea - Sugar (crushed) Vinegar Best London Porter |Ib. 3 lb. 1 lb. 6 lb. 3 Pints 42 Pints J For a Mess of Six Men per Week. Water at the rate of Seven Pints per man per day. for twenty weeks : this quantity covers Wastage. Lemon Juice at the rate of One Quart per man lor the Voyage out. The allowance of Porter to be exclusive of Wastage. Fresh TWf or Mutton to be issued to the Troops when procurable ; 1£ lb. per man per day, with Vegetables for the Soup, and Oatmeal. * New India Beef and New India Pork of British curing. APPEXDIX B. 465 QUANTITIES FOR EACH MAI * PER DAY p a r3 J! 2 '3 G ■- O 1) ■2 t, a CO 5» •d I A oz. OZ. 02 oz. 0%. oz. 5 lb. 3 j£ 3 A § .s #. |rf. lb. lb. JO/5 /&. to*. Sunday Monday Tuesday 21| 6§ »3§ 1§ 2 4 16 - - 1 1 1 u e s- a. ■A • 11 Its* IF°- V: ednesday — — — — 16 — 1=5 5, 1 Sfe i. a s ?r c o g Thursday - Friday 2I| G§ «§ — I 1 1 1 Is 2 a y a> a> Saturday — — — 16 "7^ — iO 1 _ £•.£ 5^ ** — ' r^ X hH N. B. Women receive the same rations as Men, and Children half the ration, with the exception of Beer, hall the ration only being allowed to Women. The Porter to be in Hogsheads when the number of Persons is under 120. DAILY MEALS. Breakfast Dinner - Supper - - Biscuits, Tea and Sugar. - According to the above Scale. - Biscuits, Tea and Sugar. 2. OF THE NAVY. (Dr. John Wilson. Statistical Eeports on the Health of the Navy, ordered by the House of Commons to be printed, March 24, 1840): — There shall be allowed to every person serving in his Majesty's ships the following daily quantities of provisions ; viz. Bread -----------lib. Beer --- I gallon. Cocoa - - - - - - - - - - - loz. Sugar l* oz. Fresh meat -------- -.lib. and Vegetables ---------- | lb. Tea ioz. When fresh meat and vegetables are not issued, there shall be allowed, in lieu thereof, Salt beef - § lb. ) £ and S.-3 Flour f lb. j « or Salt pork - - - - - § lb. ) £ and > S Peas | pint. ) < And weekly, whether fresh or salt meat is used. f Oafmpal t fi ninf- ( For occasional use when required, A quantity of J vfr^iTr C not exceeding } f £ ™ : { but not to be considered as subject t vinegar J 1 5 pint j tQ be paid fQr wheQ uQt ^^ H H 46G APPENDIX B. The following scheme shows the proportion of provisions with salt meat for each man for 14 days. 1 Oatmeal Days of the Week. Bread Beer. Sugar. Cocoa. Tea. Beef. Pork. Flour. Pea>. and Vinegar. lb. gall. oz. oz. cz. lb. lb. lb I :r.t. Per pint. Sunday - 1 I| I A 4 3 4 — 2 4. — " Monday - 1 U 1 1 * — § — h Tuesday - 1 l| 1 1 ¥ 3 4 — 3 4 — Wednesday 1 H 1 * — 1 — £ I * Thursday - 1 H 1 1 4 2. 4 — I — > Friday ... 1 H 1 i — 3 4 — * c Saturday - 1 1 1 i 4 3 4 1 3 4 1 4 i plained 1 Sunday - Monday - 1 U 1 1 4 — » — — X - Tuesday - 1 I5 1 1 1 4 — a 4 i Wednesday 1 4 1 4 — — Thursday - 1 H 1 1 4 * 4 — 2 I Friday - 1 H 1 4" — 4 — — Saturday - Proportion for 14 days 1 H 14 i 4 — 4 1 H 14 21 3$ 5i 5| H 1 On the days in which flour is ordered to be issued, suet, and raisins or currants, may be substituted for a portion of the flour. 1 lb. of raisins being considered equal to 1 lb. of flour. a lb. of currants ) or \- $ :b. of suet ) - ditto ditto. Change of sonic species of Provisions for others, as the Service may require. And incase it should be found necessary to alter any of the species of provisions before mentioned, and to issue others as their substitutes, it is to be observed, that 1£ lb. of soft bread, - - O in »e J&L l is to De considered equal to 1 lb. of lib. of nee, f biscuit. 1 lb. of flour J 1 pint of wine, - - - - ( i s to be considered equal to 1 gallon m i of beer. " Ms to be considered equal to 1 02. of 1 cocoa. i oz. ol tea - - - - - ) 1 lb. of rice, 1 J is to be considered equal to 1 pint of ' } peas. -J f is to be considered equal to 1 ~\ of oatmeal. f" is to be considered equal to 1 lb. of " ? sugar. C are to be considered equal to 1 lb. of "I cocoa. i pint of spirits 1 oz. of coffee, 1 pint of Calavances, or 1 pint of Dholl - 1 lb. of rice - 1 lb. of butter 2 lbs. of cheese t lb. of onions, or i lb. of leeks :}■ is to be considered equal to 1 I other vegetables. APPENDIX B. 467 The large ration of beer has been altogether superseded since 1831. Wine is only issued on the Cape of Good Hope Station. After fourteen days' use of salt food, lemon-juice, with an addi- tional allowance of sugar, is issued as an antiscorbutic. 3. OF EMIGBAXTS. (As fixed by Her Majesty's Colonial Land and Emigration Commissioners, and quoted by Dr. Pereira, op. cit.) : — The Passengers to be in Messes of six or more, as the Surgeon may determine ; and to be victualled according to the following Scale, for one Adult : — Days. = i I M o lb. •a ■ II ££ lb. j5 lb. s - oz. 3 00 OZ. oj 1 /o. • ox. O u 02. a P OZ to Qts. c P/. 3 a ox. 15 0£. lb lb. Sunday - - i _ 4 i 2 H — 4 l __ i 3 >> >> Monday 3 4 — 1 i 4 — — i — J — 3 3 2 Tuesday 4 1 — — i 2 H — 1 4 4 — 4 — 3 * £ s £ Wednesday 4 — 1 — i ■i — — 3 — — 1 — — 3 G o ■ Thursday - i — - i i 4 2 'i — 1 4 i — 1 4 — 3 S. 3 O o c Friday - - 4 — * — 1 4 — — 3 1 « — 1 — 3 3 c 3 o Saturday - 4 i — — 4 2 14 — — 4 — ~ — 3 2 lb. i- o /. -= m pq 02. c .E 1 33 i | ox. 02. oe. pa Sunday 4 Men - - - - <■ \\ omen • 7 5 5 5 1 1 ™ — 7 5 - 4 - ii Monday . P Ien - - - - t-Women - 7 5 — _ 4 2 2 : 7 5 ; — Tuesday. - P Ien - - - - (. ^\ omen ... 7 5 5 5 1 1 — _ 7 * ■i Wednesday P len " (■ Women ... 7 5 4 — — — 14 IS 7 i — i _ Thursday -P Ien - - - - (• \\ (mien ... 7 5 i| 5 5 1 1 — __ 7 5 - ii t? j C Men .... Fridiy - j C Women ... 7 5 u I 1 7 5 i i - Saturday -P' e " ■ - - - C \\ omen - . - 7 5 — — - — 14 12 7 i - Aged and infirm inmates may be allowed 1 pint of t tngar and butter, for break. fast, in lieu of the gruel prescribed by the above Table. Children above the age of nine years, and under the age of sixteen years, allowed tiie same quantities :;i the above Table. Sick as directed by the Medical Officer. Dietary for Children under Years of Age. Children from '. to5Y Breakf.st. Dinner. s ■d ■ i ■a I PC £ 1 2 = 3 — = - - m a 1 _ — « ox. pint. 02 pint. 02. lb. lb. pint. Sunday - 4 ft - — 3 1 — 1 \ Monday • 4 * 2 ft — — — A 1 Tuesday - 4 i 9 - — 3 * — i I 1 Wednesday - 4 A 1 — — — — a 4 i 1 Thursday - 4 1 — — 3 1 — a 4 * Friday - 4 A a 2 1 — 1 * Saturday - 4 k — — — ~ l 5 ' i APPENDIX B. 469 Children from 5 to 9 Years. Breakfast. Dinner. t Supper. 1 SI n O 03 S of -Q >5 c T3 0) u O -a G O n oz. pint. OX. pint. ox. ta 02. oz. 02. pm^ . pints. Sunday - 5 i 3 — — 4 i 5 — 4 - — * Monday - 5 1 2 1 — — — 4 i 2 i — Tuesday - 5 2 — — 4 1 'J — 4 — — * Wednesday 5 i - - — — 10 4 1 i 2 — Thursday 5 i — — 4 1 2 — 4 — — 4 Friday - 5 i a 2 1 — — — 4 1 1 2 — Saturday - 5 l 5 — — — — 10 4 2 1 5 — Infants under two years dieted at discretion. MERE UNION. Dietary for Able-bodied Men and Women. Breakfast. D inner. Supper. n o 3 O "2« o £ i- 9 o as n 111 10 u 01 0) A O t5 O o s o PL, 02. ;^s. 02. tt. pts. 02. 02. 02. 02. 02. ff>. Sunday . P Ten - " I Women - 7 6 — — — 7 6 11 4 7 6 *2 1* Monday - P Ien - ' c Women - 7 6 3 3 1 1 — 8 7 __ — 7 6 *2 J 1 Tuesday - P len " " t Women - 7 G — — - 6 5 — 7 G 1 1 *2 Wednesday [ Men (■ Women - 7 6 1 1 J 2 — — — 16 14 I z 7 6 1 1 J 3 11 l 2 __ Thursday P* en " " t Women - 7 6 3 3 1 1 8 7 — - 7 G H 1 1 'a — Friday - [ Men " " c Women - 7 6 — __ 1 1 1 2 — G 5 — 7 6 ] l 1 1 *2 — Saturday -* Men " " I Women - 7 6 - — - 16 14 — - 6 1 1 2 1 1 H H 3 470 APPENDIX B. Table A. Children from 2 to 5. Breakfast. Dinner. Supper. I ja fcc M - c § i £ ~ S.c « -i i :* 4 - 1 > x E. i ll X 1 = 11 02. pts. 02. OX. /',. 02. 02. tff. OX. 02. ox. ;,-c. Sunday - 4 — — _ _ — 8 1 4 i 1 Monday - 4 1 3 — I — — — — — 4 i 4 1 Tuesday - 4 1 - — — — 4 I — — 4 1 Wednesday - 4 1 - — x — — _ 4 i * Thursday - 4 1 3 — i 4 1 1 Friday - 4 1 - — — 4 § — — 4 \ i Saturday - 4 1 - 3 I — — — — 4 i 1 Table B. Children from 5 to 9. Breakfast. :.er. Supper, j ■= i - s j i C - -£ i.e. j m utton Broth. it,,,-. /. 2 i * 02. pts. 1 lb. OX. :. x. B. Sunday • - 5 1 - — - — — — u 1 5 1 1 Monday - 5 3 4 4 — 1 - _ - - — ' 1 ■ 1 Tuesday - 5 f — - — — 5 f - — 5 1 1 * Wednesday • 5 4 — — - 10 — 5 1 » 4 Thursday - 5 1 4 •4 — _ 4 — — _ — 5 1 f « Friday - 5 t — — — — 5 f - — 5 1 I Saturday - 6 1 — 4 4 — — ' 1 3 4 Old people of 60 years of age and upwards may be allowed two pints of tea per day with milk or sugar, in lieu of gruel, with 4 ounces of butter, and 4 ounces of cheese per week, if deemed expedient to make this change. Children under 2 years of age may be dieted at discretion. Sick to be dieted as directed by the Medical Officer. 5. OF SLAVES. The weekly allowance of negroes (Olmsted, op. ciif.) in the Southern States is about 1^- — 1-J. peeks of Indian corn, or ita meal, and 3 — oh lbs. of bacon or pork. Other food is. howc often added by themselves : — APPENDIX B. 471 6. OF PRISONERS. Table of Dietaries for Prisoners, as certified by the Right Honourable Sir George Grey, Bart. M.P. one of Her Majesty's Principal Secretaries of State, on the 15th day of June, 1857. CLASS 1. Convicted Prisoners sentenced to any term not exceeding Seven Days : — Males. Females* Breakfast Oatmeal gruel - - 1 pint. Oatmeal gruel - - 1 pint. Dinner Bread - - - - 1 lb. Bread - - - - 1 lb. Supper Oatmeal gruel - - 1 pint. Oatmeal gruel - - 1 pint. CLASS II. Convicted Prisoners sentenced to any term exceeding Seven Days, and not exceeding Twenty-one Days :— Males. Females. Breakfast Oatmeal Gruel - - 1 pint. Oatmeal Gruel - - 1 pint. Bread - - - - Goz. Bread - - - - 6 oz. Dinner Bread - - - - 12 oz. Bread - 6 oz. Supper Bread - 6 oz. Bread - - - - 6 oz. Oatmeal Gruel - - 1 pint. Oatmeal Gruel - - 1 pint. Prisoners of this Class employed at hard labour to have, in addition, one pint of soup per week. CLASS III. Convicted Prisoners employed at hard labour for terms exceeding Twenty-one Days, but not more than Six Weeks ; and convicted prisoners not employed at hard labour for terms exceeding Twenty one Days, but not more than Four Months : — Daily. Males. Females. Breakfast Oatmeal gruel Bread - - 1 pint. Oatmeal gruel - 6 oz. Bread - - 1 pint - 6oz. Sunday and Thursday. Dinner Soup - Bread - - 1 pint. Sonp - - 8 oz. Bread - - - 1 pint. - 6 oz. Tuesday and Saturday. Dinner Cooked meat, without bone 3 oz. Cooked meat, without bone 3 oz. Bread - 8 oz. Bread - - - - 6 oz. Potatoes - - - - | lb. Potatoes - - - - A lb. Monday, Wednesday, and Friday. Dinner Bread - 8 oz. Bread - - - - 6 oz. Potatoes - - - 1 lb. Potatoes - - ] lb. Daily. Supper Same as Breakfast. Same as Breakfast. H H 4 472 APPENDIX B. CLASS IV. Convicted Prisoners employed at hard labour for terms exceeding Six Weeks, but not more than Four Months; and Convicted Prisoners not employed at hard labour for terms exceeding Four Months : — Daily. Males. Females. Breakfast Oatmeal gruel - - 1 pint. Oatmeal gruel - - 1 pint. Bread - - - - 8 oz. Bread - - - - 6 oz. Sunday, Tuesday, Thursday, and Saturday. Dinner Cooked meat, without bone 3 oz. Cooked meat, without bone 3 oz. Dinner Potatoes Bread - - i lb. Potatoes - 8 oz. ] Bread - - lib. - b oz. Malet. Monday, Wednesday, and Friday. Females. Soup - Bread - - 1 pint. Soup - - 8 oz. Bread - - 1 pint. G oz. Supper Same as Breakfast. Same as Breakfast. CLASS V. Convicted Prisoners employed at hard labour for terms exceeding Four Months : — Sunday, Tuesday, Thursday, and Saturday. Males. Females. Breakfast Oatmeal gruel - - 1 pint. Oatmpal gruel - - 1 pint. Bread - s ox. I - - - - G oz. Dinner Cooked meat, without bone 4 as. I oked meat, without bone 3oz. Potatoes - 1 lb. Potatoes - Bread - - - - G oz. Bread- .--- Monday. Wednmday. and Friday. Breakfast One pint of cocoa, made of ^ oz. of flaked cocoa or cocoa nibs, sweetened with \ oz. of mo- lasses or sugar. Bread - - - - 8 oz. Dinner Soup - 1 pint. Potatoes - - - 1 lb. Bread - - - - G oz. Daily. One pint of cocoa, made of f oz. of flaked eocoa or cocoa nibs, ■ ith f oz. of mo- Bread • - - -6 oz. - 1 pint. P tatoei Bread .... Supper Oatmeal gruel Bread . - 1 pint. - 8 oz. Oatmeal gruel Bread - - 1 pint. - 6 oz. CLASS VI. Prisoners sentenced by Court to Solitary Confinement : — Males. The ordinary diet of their respective classes. Females, The ordinary diet of their respective II B. CLASS VII. Prisoners for Trial and Examination. Misdemeanants of the First Division, who do not maintain themselves, and Destitute Debtors: — Males. Fern a Its. The same as Class IV. The same as Class IV. CLASS VIII. Debtors committed under the Sth and 9th Vict., cap. 1'27. and 9th and 10th Vict., cap. M ; Fraudulent Debtors committed by Commissioners of Bankrupts under the Bankruptcy Laws : and Debtors remanded for Fraud from Insolvent Debtors' Courts : Males. Fer; The same as Class III. The same as Class III. APPENDIX B. 473 CLASS IX. Prisoners in close confinement for Prison Offences for terms not exceeding Three Days: — 1 lb. of bread per Diem. Prisoners in close confinement for Prison Offences under the provisions of the 42nd Section of the Gaol Act : — Daily. Males. Females. Breakfast Bread - . . - 8 oz. Bread - - - - 6 oz. Gruel - - . - 1 pint. Gruel - - . - 1 pint Dinner Bread - . - - 8 oz. Bread - . . - 6oz. Supper Bread - - . - 8 oz. Bread - . - - 6 oz. Gruel - - - - 1 pint. Gruel - - - - 1 pint Ingredients of Soup and Gruel — The Soup to contain, per pint, 3 ounces of cooked meat, without bone, 3 ounces of potatoes, 1 ounce of barley, rice, or oatmeal, and 1 ounce of onions or leeks, with pepper or salt. The Gruel to contain 2 ounces of oatmeal per pint. The Gruel on alternate days to be sweetened with f ounce of molasses, or sugar, and sea- soned with salt. In seasons when the potato crop has failed, 4 ounces of split peas made into a pudding maybe occasionally substituted ; but the change must not be made more than twice in each week. Boys under fourteen years of age to be placed on the same diet as females. At various prisons — for instance, the Hulks, Coldbath Fields, Millbank — the diet of class 5 is enriched by the addition of 1 to 2 oz. of meat, and ^ pint of soup, daily, as well as modified by the substitution of cocoa for the gruel at breakfast. IRISH PRISONERS. (Lieutenant Boyd, Governor of Londonderry Gaol. From the " Times " of March 29, 1861.) Prisoners committed for more than One Month, and aged More than 15 years. Breakfast f females 7 \ 07 " oatmeal and ] P int of buttermilk. Dinner [ f^l\es 12] oz ' bread ' [f ] pint newmilk - Less than 15 years. Breakfast females ? 5 oz - bread, and 1 pint buttermilk. Dinner 5 Females i 8 oz " bread ' and 1 oz ' oatmeal in gruel. Potatoes, for [p^ies 3* ] lbs * may be substituted for bread. Gruel must be substituted for milk 2 days a week. 474 APJPEXDIX B. 7. OF HOSPITAL-PATIENTS. ST. THOMAS'S HOSPITAL, LONDON. Soup Diet. Milk Diet. Simple Diet. 12 oz. of bread. | oz. of butter. 8 oz. of beef or mutton, when dressed ; roasted or boiled. on alternate days. £lb. of potatoes, or green vegetable- in spring and summer occasionally. 2 pts. of beer (Men.) 1 pt. of beer ( Women ) 1 pint of tea with milk and sugar at breakfast and at tea. Broth on boiled meat days for supper. When porter is ordered, beer to be omitted. 12 oz. of bread. | oz. of butter. 4 oz. of beef or mutton when dressed ; roasted orboiled, on alternate days. i lb. of potatoes or ^reen vegetables in spring and summer occasionally. 1 pint of beer. 1 pint of tea with milk and sugar at breakfast and at tea. Broth on boiled meat days lor supper. 12 oz. of bread, foz. of butter. 12oz.ofbread. 12oz. ofbread f oz. of butter. I oz. of butter. 1 pint of tea 1 pint of tea | pint of tea with milk and with milk and with milk and 6 oz. ofbread. 1 pint of barley water or gruel for each meal. sugar at breakfast and at tea. 1 pint of beef tea strong enough to form a jelly when cold, — with half allowance of rice or bread pudding for dinner, and $ pint milk. If fish is ordered, beef tea to be omitted. sugar at breakfast and at tea. 1 pint of milk with rice or bread pudding alternately for dinner". sugar at breakfast and at tea. Half allow- ance of rice or bread pudding, and | pint milk. 4 oz. meat when d ' d iyt, boiled 1 day.) If fish is ordered, meat to be omitted. Children under ten years of age to be allowed two-thirds the quantity of each diet prescribed for adults. MARGATE METROPOLITAN ESTABLISHMENT FOR SCROFULOUS CHILDREN. Diet Table from 5 to 10 yean of Four or five oz. bread and butter, and |-ptnt milk in Three or four oz. roast or boiled meat, frith $-lb. potatoes, or potatoes and bread, or other vegetables, $-pint London porter, on Sunday, Monday, Tuesday, Four or five oz. bread and Thursday, and Friday. Eight or twelve oz. of either rice or currant padding, on Wednesday and Satur- day. Soup occasionally, in lieu of pudding. butter, and |-pint milk in water. APPENDIX B. 475 From 10 to 16. Breakfast. Dinner. Supper. Five or six oz. roast or boiled meat, with 1 lb. potatoes, or other vege- tables, or £-lb. potatoes, and 3 oz. bread, |-pint London porter, on Sunday, Six or seven oz. bread and Monday, Tuesday, Thurs- Six or seven oz. bread and butter, and f- pint of tea. day, and Friday. Sixteen oz. of either plum or currant pudding, on Wednesday and Saturday. Soup occasionally, in lieu of pudding. butter, and f-pint of tea. PARISIAN HOSPITALS. (Summary by a Correspondent of the Lancet, 1861, vol. i. p. 302.) Full Diet consists of White bread, 20 oz. Wine, mostly Bordeaux, \ to 1 pint Soup, f pint, twice daily. Bouilli, 9 oz. Cooked vegetables, 1 pint. Milk,i to 1 pint. daily. The above Dietaries are offered merely as samples. All of them, however, have been tested by experience ; and, apparently, found sufficient. The application, to these Dietaries, of many of the considera- tions mentioned in Chap XIII., is so obvious, as to spare us the necessity of any criticism of their details. But at the risk of repetition it may be useful to point out, that no direct comparison of them is available ; and that even an indirect one can only possess any significance, by taking cognizance of the following circumstances. 1. The amount of labour of the person; the quantity and rich- ness of the food necessary to sustain health increasing, within certain limits, in proportion to the severity of the toil (p. 434.). 2. Some of the above diets are supplemented from other sources ; in other words, only represent part of the food, the remainder 476 APPENDIX B. being either habitually obtained by the persons rising them, a3 in the case of soldiers and slaves ; or often prescribed as extras, as in the case of Hospital patients. 3. The quantity and quality of a Dietary (p. 424 ) is often in- creased as a counterpoise to sources of ill-health, either un- avoidable or overlooked by the authorities of Institutions. The unhealthy situations of Millbank and the Hulks on the Thames, and the depression of spirits induced by the prospect of long im- prisonment, have thus been humanely compensated ("the latter in consonance with an excellent report by Sir James Graham) I richer diet. In like manner, the exhausting die Mdergone by our Hospital patients often require the application of the - rule, especially during convalescence. And if. as many think, the children reared in workh show mark- of in- sufficient Nutrition, it is clear, from a com] their Dietary with that of one of our m< 3l -: oJ Bospi (the Margate Infirmary > that it is not to an absolute (perhaps scarcely even to a relative) deficiency of food that we can attri- bute their deficient health and strength. The -ome of the least efficient, and most dem members of our community, might well I some of the characteristics of their immediate ancestry. But it may be suspected that neither insufficient food, nor an unhealthy descent, are altogether answerable for any such phj vene- ration ; and that it is to a want of such stimuli a- love and b not to say fresh air and e\ rather than to a mere defici of beef and pudding, that the feeble health of pauper children ften due. INDEX. Abdominal pressure, 217, 457. Acid, acetic, 343. benzoic, 23. butyric. See Butyric Acid, capric, 289. capronic, 299. caprylic, 289. citric, 23, 343. lactic. See Lactic Acid, malic, 318, 325. oxalic, 1G, 23, 343. phosphoric, 269, 306, 318. tartaric, 23. vaccinic, 289. Acids, as condiments, 343. action of, on pepsine, l*/3. Acorns, 317. Adipose tissue (also see Fat), 253, 202, 263, 273,402,419. ^Ether, 309, 451. Age, as influencing meat, 274. Albumen, 13, 14, 37, 53, 54, 254. Albuminous substances, 12, 20, 444. tissues, 12, 32, 34. Alcohol, its action on pepsine, 124. abuses in disease, 449. uses in disease, 449, 450. equivocal effects, 451. administration, 452. reaction, 305, 390, 391, 395. elimination, 387. influence on digestion, 395—397. ingestion, 396. hunger, 390. longevity, 391. secretions, 383, 384, 386, 388, 395. the functions, 376, 377. bodily waste, 378, 380—386. temperature, abstinence from. exertion, 389 See Teetotalism. Alcoholic drinks, 365—398. their relation to food, 305, 370, 394, 396. classes, 366. physiological effects, 374— 3S8. Ales, 306, 367, 374, 382, 392. bitter, 307. Algce, 330 Alkalinity of intestinal juice, 149. pancreatic juice, 179. bile, 191. saliva, 78. Alkalis, action of, on pepsine, 123. Alkaloids of condiments, 342. Ammonia, 4, 5, 6, 7, 16, 385. Animal body, derivation of, 45. contrasted with plant, 45. heat, 9, 11, 12,27, 28,32. Anselmino, 7. Apothema of wine, 371. Apples, 324. Apricots, 324. Arab, as illustrating exalted nutrition, 441. Arctic regions, nutrition in, 437. Asafcetitia, as a condiment, 341. Asparagin, 318. Asparagus, 328. Baking, 410. Barley, composition of, 303. Batrachia, 07. Beans, 31 G. Beaumont, Dr., 82, 118, 128, 129. Becquerel, 06. Beef, lean of, its composition, 254. of ox, its analysis, 279. Beers, 3G6, 367, 374, 382, 389. Beet-root, 323. Benedek, 365. Bernard, CI., 118, 129, 181, 197, 258. Bernays. Dr., 360, 385. Berzelius, 194,330. Bibra, von, 262. 478 IXDEX. Bickon, 306. Bidder, 30, 58, 66, 80, 118, 149, 150, 195, 243. i; i Biestings. See Colostrum. Bile, its composition, 193, 194. quantity, 191. physical properties, 191. transit in the ducts, 192, 193. excretion, 195. reabsorption, 195. sources, 196. influence on digestion, 196, 197. nitrogen, 198. Birds, 48, 52, 249. flesh of, 277. Blondlot, 82, 118. Blood, 32. a seat of combustion, 21, 23. as food, '279. liquor. See Liquor Sanguinis. corpuscles, 27. waste of, in hybernation, 35. in starvation, 32, 35, 37. Boecker, 353, 358, 360, 3G1, 378. Boiling, 407—410. Bone, its rate of waste, 25. value as food, 255, 260, 281. Bordeaux wines, 371. Bouilli, 409. Bouillon, 409. Boussingault, 58, 259, 306, 318. Braconnot, 315. Brains, as food, 280. Brandy, 372, 382. Bread, its preparation, 309. choice, 310. value, 310, 311. Bruecke, 160. Brunn or Brumier, 84, 174, 178. glands of. See Duodenal Glands. Buckwheat, composition, 303. Buffalo-meat, 273. Burgundy wines, 371. Butter, 59, 265. 886, Ma its dietetic value, 290. Butyric acid, 16, 269, Cabbage, 328. Cachectia, 37. Caecum, 132, 201—206. attachments of, 201. size of, 201. mucous coat of, 203. muscular coat of, 202. apertures of, -03. use of, 206. Caffein, 349, 362. Caffetannic acid, 349. Carbonates, formed in body, 17, 23, 68. Carbonic acid, 16. exhaled by skin, 4. by lungs, 5. source of, 9. Cardiac aperture of stomach, 87. Carnivora, 56, 206, 234, 247, 249, 260. Carotin, 324. Carp, flesh of, its analysis, 279. Carpenter, Dr., 311. Carrageen, 330. Carrot, 323. Cartilage, 25, 253, 257, 260. Castration, as influencing meat, 274. Cat, 58. Celery, 328. Cellulose, 62, 302, 303, 305, 318, 328. Cere alia, 63,301—314. their composition, 303. range df climate, 304. value, how estimated. ash, analyses of, 3' 6. preparation, 307 -314. variations of constituents of, 305. Champagne, 373. ChevrmK 118, 238. Cheese, 290— I its composition, 290, I .. digestibi'.ir; value, 294. ! varieties, I changes by keeping. S Chestnuts, 317. Chicken, flesh of. its analysis. _~ Childhood, diet in. 426. Chlorides, of cgesta. 7, 17, 31. 237 (all Salt). of the bile, 184. blood, 269. gastric juice, 119, milk, muse'. rS, 79. pancreatic juice, 17J. Chlorophyll, 194, Chocolate. 40, 361—364. Choice of food. 5,v Diet. Cholera, 36. Cholestearine, 194. Cholicacid, 194. 198. Chondrin. 5?. Ghaaaaf, 30. Cinnamon, 341. Climate. Arctic. I i Tropica).::. N Cobbett, 319. INDEX. 479 Cocoa, its composition, 362. mechanical ingredients, 361. preparations, 363. its nutritive properties, 363, 364. Cod-liver oil, 234, 332. Coffee, historic influence of, 345. its composition, 346, 349. contrast with tea, 350, 354. decoction, 350. roasting, 349. physiological effects, 351—360. effects influenced by habits, 356. effects influenced by idiosyncrasy, 356. effects influenced by occupation, 352. experiments on its action, 353, 360, 365. Collagen, 55. Collagenic tissues, 255, 257, 259, 2G0, 273, 278. Colon, its structure, 208. appendices epiplotcce, 209. peristalsis, 211, 212. mucous membrane, 212. ascending, 201, 207. descending, 201,207. sigmoid flexure of, 199, 201, 208. transverse, 201, 207. Colostrum, 282, 283. Combustion of the tissues, 9, 16. bodily, its sites, 23. 24. of hydrogen, 9, 359, 384. of protein, 12, 16,33, 270. of fat, 10, 11,28,32, 33,419. Condiments, 331—343. acrid or heating, 337. alliaceous, 340. complementary, 343. definition of, 331. acid, 343. relations of, to food, 332. medicine, 332, 339. secretion, 338. Cookery, 394, 399—415. its general value, 399, 404. effects on meat, 401, 402. import, 402. the flavours it developes, 403, 404. its processes, 405 — 415. economy, 400, 404, 415. Cooling, process of, in hot climates, 439. Corvisart, Dr., 182. Cream, 288. cheese, 291. Curacoa, 373. Date, 329. Dauglish, Dr., 309. Decay, in old age, 2, 429. Deer, flesh of, 262, 268. Defalcation, 216, 217, 218, 457. Degluttion, 85—87. Delajond, 160. De Morgan, 25. Depurative functions, relation of diet to, 426, 432, 447. Dextrine, 62, 324, 329, 330. Diet, 416-453. how far calculable, 417—420. as influenced by chemistry, 421. results of insufficient, 421—423. definition of a good, 423. compensates injuries, 424. value of physiology to, 425. as influenced by age, 426—431. habits of life, 433— 435. disease, 441. sex, 431— 433. race, 440, 441. climate, 435—441. Dietaries (Appendix B.), 464. of soldiers, 461. sailors, 465. emigrants, 467. prisoners, 471. paupers, 468. hospital patients, 474. children, 468—470, 463—465. Digestion, etymology of, 70. definition of, 70. summary of, 71. in the stomach, 130. large intestine, 230. small intestine, 198. caecum, 230. wear and tear of, 245, 430. * disease of the organs of, as af- fecting diet, 442. Disease, influence of, on meat, 274. Dog, 58, 79, 141, 258, 260, 458, 460, 461. Drink, distinction from food, 40. Dulong, 33, 419. Dunglison, 118, 122. Duodenal glands, 84, 175—178. function of, 177. structure of, 176. Duodenum, 134, 135. Duroy, 387. Dysenteric purging, 38. Egesta, their channels, 3. physical form, 4. constituents, 4—8, 480 IXDEX. Egesta, their sources, 8 — 24. Eggs, 52, 281. their value as food, 258, 281. composition, 281. Einhof, 318. Elimination of alcohol, 3S7, 388, 452. fever, 450, 461. excretory matters, 38G, 447. Also see Egesta. Enderlin, 118. Enemata, 449. Erdmann, 306. Eructation, 455, 456. Evaporation, 359, 383, 439. Exertion, influence of, on diet, 433—435. bodily, its relation to alcohol. 3^9. diet, 434. mental, alcohol, 389, diet, 435. Fasces, 5, 6, 232-237. their colour, 232. odour, 232. bile, 194, 232, 233, 236. sources, 232. composition, chemical, 236. mechanical, '234. Fat, 8, 10, 11,27,32,33, 51 its relation to the blood, 11, 61. proportion in the body, 61. proportion in meat, SG2. diverse sources, 263. composition, '263, 264. digestibility, 264, 2G"\ value as food, 264 — 266. results of its excess, 267. Fattening of animals, 63, 64, 334. 441. uses of water in, 66. Fatty acids, 267, 383, 384. Fatty tissues, 27. 32. their uses in the body, 60. Fever, 6, 28, 29, 37. diet in, how regulated, 448 458 . tvphoid, 37, 449. tvpfci .449. Fibrine, 53, 54. Figs, 329. Fish, flesh of, 878. Fistuhe, gastric. 82. intestinal, 141, 231. Flesh. See Meat. Foetus, intestinal contents in, 233. Follicles, definition of, 166. agminate, site of, 166. structure of, 169—172. function of, 173. solitary. 166. 173,212. Food, its purposes. 1, 21. Food, definition of, 39. constituents of, 52. organic in its nature, 43. quantity of, 419— 421. relation to bodily waste, 43. variety essential, 51, 327, 418. of plants and animals contrasted, 45. ideal of any animal, 247. animal, 246—295. contrasted with vegetal W, 250—252. natural to Man, 247—249. influence of, 2=>0. vegetable, it* characters, 296. essential, _ J harmless in superfluity, 299. variations of, 300. varieties of, 301—330. Ford, 364. Frci, 171. Frcrichs, 58.1 18,149,193^59, 259,295. ! Fit sen ,us. 306. Fruits, 324 — 3^7. their composition. 324. nutritive value, 325. Funguses, 329, 330. Gall-bladder, 190-193. Game-fowl, flesh of. 178. Garlic, 341,343. Gases of a'iraentary canal, 23*— 212. Gastric juice, 117—131. chemical properties of. 1 7— 121. physical properties of, 117. acids of, 11*— 120. action of, 121. salts of, 119. organic principle of. Pepsine. Gelatin, 16, 23, 37, 50, 55, 255. its varieties its sources, 255. value to nutrition, 256 — 261. cookery, 2"" • . . I I See Butter. Gin. 373. 3^2. Glands as food Gluten, 303, 305, 3 - Glycin, 16, 194. Glycogen. 1; - Gooldctu £>>-.. 36 \ G>\ - Gravy. 406. Green herbs, 32*— their compositier nutritive 1 1 Greic, 166 INDEX. 481 Growth of young animal, 2, 426. Gruby, 160. Gum, 62, 314, 315, 324, 326, 327. Hare, flesh of, 262. Hayes, Dr. J., 436. Heart, muscle of, as food, 272. Heat, animal. See Animal Heat. Heat of combustion of carbon and hydrogen contrasted, 33. fat and sugar con- trasted, 419. Hepatic vein, 188. composition of its blood, 198. Herbivora, 55, 56, 67, 206, 247, 249. Hippuric acid, 16. Hcematin, indigestibility of, 280. Horse, 58, 249. Horse-radish, 341, 342. Horsfurd, 303, 319. Hunger, 26, 36. Hunger, in starvation, 29. Husk, 302, 303, 305, 307, 308, 361. Hybernation, 26, 27, 35. its effect on various tissues,27. excrements during, 233. Hydrates of carbon, 52, 418, 419, 440. Hydrocarbons, 52. of the fatty tissues, 10. quantity in body, 10. combustion of, 11, 35. in the blood, 11. nervous tissues, 11. Iceland-moss, 330. Ileo-ccecal valve, 204—206. its structure, 204. mechanism, 205. function, 20G. Ileum, 136. Inanition. See Starvation. Ingesta, variations of, 26, 28. not all food, 42. preponderance of, during growth, 2, 426. Inosinic acid, 16, 271. Inosit, 15, 16, 62, 264, 271. Insalivation, 72. Intermediate circulation, 244. Intestine, large, 191—245. its contents, 229. sojourn of food in, 231. digestion in, 229. its divisions, 201. situation, 199. size, 200. movements, 209—212. diet in ulceration of, 443. Intestine small, 132—198. size of, 133. situation, 133. movements of, 138—144. muscular coat of, 138. mucous coat, 144 — 178. Intestinal arteries, 220—223. capillaries, 226. gases, 237—243. analyses, 238. nature, 238—242. sources of, 238—242. expulsion of, 243. eliminative, 243. veins, 223— 225. (Also see Portal Vein.) mucus, 233. nerves, 227—229. distribution of, 227. communications of,'228. functions of, 228, 229. Intestinal juice, 147—150. Inulin, 324. lnvcrtebrata, 48. Jejunum, 136. Johnstone, 361. Jones, Dr. Beyice, 120, 354, 385. J urine, 238. Kane, Dr., 266. Kidneys, as food, 281. Kiernan, 184. Koechlin, 306. Koelliker, 160, 172, 190. Koerte, 318. Kohlrausch, 220. Kreatine, 16, 17, 270. Kreatinine, 16, 17,270. Krocker, 303, 318. Lactation, 282, 286, 432. Lactic acid, 15, 16, 270, 292, 299. Lallemand (L?idge)-) , 387. Lampadius, 318, 362 Lassat'gne, 118. Leeks, 341,342. Legumes, 314— 317. composition of, 314. cooking of, 316. dietetic value of, 315. Legumin, 349 Lehmann, 58, 66, 118, 119, 125, 149, 197, 268, 269, 277, 283, 353, 361. Lemon-juice, 343. Lentils, 316. Letellier, 306. Lettuce, 328, 329. I I 482 INDEX. Levator anl, 215, 216, 217. Liebig, 63, 64, 378. Life, as involving metamorphosis, 2, 46, 65, 365, 380. animal and vegetable, its sum, 43. Ligament, 253, 260. L'Herilier, 286. Liqueurs, 367, 372, 373. Liquor Sanguinis, 24. its ash, contrasted with that of the corpuscles, and of muscle, 269. Liver, 27, 32, 64, 182—198. its structure, 184—190. function, 190—198. value as food, 281. ; Livingstone, Dr., 337. Ludwig,8\, 141. Madeira wine, 372, 373. Magendie, 238, 242. Maize, its composition, 303, 304, 306. preparation, 308. Mangold, 323. Maraschino, 373. Marchand, 'i38. Marmot, during hybernation, 26, 35. Mastication, 71. Matteucci, 164. Meat, etymology, 252. its mechanical ingredients, 2"3. composition, 254 — 271. varieties, 271—279. ash of, 268. Melon, 329. Metamorphoses of digestion, 51. Mialhc, 125. Michaelis, 318. Milk, 52, 282, 426. case in of, 56. analysis of, in ass, 283. cow, 283. dog, 283. goat, 283. mare, 283. sheep, 283. man, 2S3. its quantity, 284. variations, 282—287. physical arrangement, 287. effect of lactation on, 286. alimentary products of, 288. hydrocarbons of, 59. hydrates of carbon of, 62. Millet, 303. Mitscherlick, 291. Mixture of food instinctive, 51, MoleschoU, 306. Mosses, 330. Mouse, 58. Mueller, 294. Muscle, 14, 15, 25, 55. its waste in starvation, 32, 34. hybernation, 27. Muscular juice, 24. tissues, 22. exertion, as influencing meat, 276. substance, 12, 13, 19, 258. as food, 252—279. varieties of, 271—279. Mustard, 329. Nervous tissues, nutrition of, 26. Neubauer, 13, 386. Nitrogen, its proportion in urea, 6. 12. cheese, 294. Noyau, 373. Nutrition, ideal of, 3. site of, 1 B. chemistry < aided by secretions apart from fooda 244. in the child, female, 431. Nutritional fluids. M. Nuts, 317. mposition of, 303. (Esopfa Oils of condiments, 342. Old age, diet In, 429. Onions, 341, 842. Oxid .• Oxygen, 10, IS, 27, 31,41. Pancreas, 178—182. its structur secretion, 179. function, 1^0. value as food. 281. action on starch, fat, 181. protein-compounds, 182. Papilla; of the stomach, 129, 130. intestine. See Villi. Parsnip. 323. Pa yen, 118. Peaches. 321. Pears. 324. Tease, 316, 317. Pectin, 324, 326, 330. Pern mi can. ! Pepper, 337. 341. 342. Pepsine. 120, 121. 125. Peptone, 19,20, 125, 126, 131. INDEX. 483 Peptone, formed by gastric juice only, 131. Peristalsis, of oesophagus, 87- small intestine, 138—143. P err in {Maurice), 387. Peyer, 166. Pharynx, in deglutition, 86. Phosphates, of the egesta, 7, 8, 17, 30, 236. milk, 69, 285. saliva, 78. gastric juice, 119. blood, 269. muscle, 269. bile, 194. food, 269, 307, 321, 427. Pigeon, flesh of, its analysis, 279. Plums, 324. Pork, its analysis, 279. Port wine, 372, 373. Portal blood, its circulation, 226. decomposition in the liver, 197. Portal vein, 186, 188, 224, 225. rate of its current, 226. its anastomoses, 225. its distribution in the liver, 186. Pot aufeu, as a variety of boiling, 408. Potato, its anatomy, 317. composition, 318. political influence, 319. value as food, 321—323, 421. Pregnancy, as influencing diet, 432. nutrition, 431, 433. Protein, 12, 13, 16, 49, 53, 301, 303, 308, 311, 314, 323, 324, 418. nature of, 53, 54. compounds, 53. composition of, 12, 16, 55. digestibility of, 58, 418, 453. Prout, Dr., 118, 127. Prunes, 329. Ptyalin, 80. Puchero, as a model stew, 413. Pulse. See Legumes. Putrefaction of food, 274. as affecting cookery, 401, 414. health, 414, 428. Quadrumana, 249. Rabbit, 210. Raisins, 329. Rape, 323. Rectum, 212—220. its course, 213. muscular coat, 214. serous coat, 214. Rectum, its sphincter muscles, 215. Rectum, its mucous membrane, 219. mucous folds, 219. suspensory muscle, 220. Rennet, 291, 292. Repletion, diseases of, 445, 446. diet in, 445, 447. Reptiles, 48. Rice, its composition, 303, 306. range of climate, 304. nutritive value, 304, 305, 314, 421. Ridges, of gastric mucous membrane, 105, 130. Rigor mortis, as affecting cookery, 414. Roasting, 405. Roe-deer, flesh of, its analysis, 279. Rugce of the stomach, 105. Rum, 373, 382. Rye, its composition, 303, 306. nutritive value, 307. Saalmueller, 329. Saliva, 78, 79. its composition, 79. reaction, 79. quantity, 80. secretion, 81, 82. action, 83 — 85. fermentation, 80. Salivary glands, 72. structure of, 73—77. secretions of, 77, 78. Salmon, 278,414,415, 426. Salt, as a condiment, 333 — 337, action of, 333. instinctive craving for, 333. deficiency of, its results, 333. excess of, its results, 335. Salts of egesta, 6, 17, 31. the sweat, 7, 386. urine, 7. food, 68, 418. Sarcosin, 16. Scklossberger, 278. Schmidt, 30, 58, 66, 80, 118, 119, 126, 149, 150, 195,198,243, 269. Schneider mann, 330. Schroeder, 118. Schwarzenberg, 141. Scurvy, 38, 69. Scurvy grass, 332. Sedentary, diet for the, 433, 434. Serum, 24. Sherry wine, 372, 373. Siemens, 318. Simon, J. F., 282, 283. Skin, 3, 5, 7,11, 25, 64. Smith, Dr. E., 360, 361, 381, 382. Smith, F G., 118. II 2 484 IXDEX. Soup, 407, 409, 411,412. Spinach, 328, 329. Spittle. See Saliva. St. Mar tin, Alexis, case of. See Beaumont, Br. Starch, 62, 64, 83, 85, 299, 302, 303, 309, 311, 314-318, 324. Starvation, 28, 53. varieties of, 29, 6. date of death in, 30. loss of substance in, 30. egesta during, 30. influence of, on the several tissues, 32. water on, 65. Stewing, 410—413. Stomach, 88—131. attachments of, 90. areolar tissue of, 110. cardiac aperture of, 87, 98. digestive changes in, 117. lenticular glands of, 10'J. lymphatics of, 116. matrix of, 109. movements of, 98—103. mucous coat of, 104—109. muscular coat of, 91- pyloric valve of. 90, 103. diet in disease of, 443. nerves of, 115. serous coat of, 94. tubes of, 105—109. vessels of, 111—115. shape of, 88. size of, 90. situation of, 91. movements of food in, 100—103. cell-growths of, 107—109. secretion of. Sec Gastric Juice, protective mucus of, 119. Succulent roots, 323 — 327. Sugar, 16, 21, 37, 62, 63, G4, 2>3, 323. 320, 328, 360. 373, 37-1, 419, conversion of starch in: influence of, in alcoholic liquids, 374. Sulphates, 7, 30. 68. Sulphocyanide of potassium, 79, 80. Sulphocyanogen, 342. Sulphuretted hydrogen, 6^. Sweat, constituents ot\ 7. Sympathetic nerves, 116, 227. Syntonin, 13, 20, 254. Taurin, 194, 195. Tauro-cholie acid, 194. Tea. its historic influence. 34~>. composition, 347. contrasted with 334. infusion, Tea, its physiological effects, 352—360. nutritive value, 344, 350, 351. experiments on its action, 360, 364, 365. kinds of, 346. effect of, influenced by idiosyncrasy, 357. habits., 3-56. occupation, 352. Tee-totalism, 322, 3S3, 3S9, 391—398. Teeth, 71, 72. Tench, peristalsis in, 143. Tendon, 255, 257, 260. Thein, 347, 362. Theobromine, 362. Thirst, death by, 28, 36, 65. Thomson. Ii.D., 118. Tiedemann. 118. To mo Tongue, 72, 272, I Trip Trout, flesh of, its ana Tubes, of stomach, 105— small int' large intestine, - Turbo: Turn . 332. Tamil ration, S8. Unstriped muscle, as fo<> J it> relation to the urine, 6. food its quantity, 6. variations, 6. sources, 12, 13, 14. allied substances, 4, 15, 16, 386. Uric acid, 16. of eg I Urine, its import, 65. FmkM -.164,437. J'tjlvuLr continents Van ill.; Veal, its anal] nfl -" :arianism," unnan. inaccuracy . 323*. Vermiform appendix, 201, 206. - Villi, 152-165. Shaj INDEX. 485 Villi 9 structure of, 154. lacteal s of, 157. blood-vessels of, 156. muscular coat of, 159. movements of, 159, 160. changes of, during digestion, 163. absorption of fat by, 163. aided by bile, 196. Vinegar, 343, 367. Vogel, 7, 13, 318, 386. Vomiting, 455—463. conditions of, 453. agents of, 457. phenomena of, 458. causes of, 459. how far " reflex," 460. nature of, 460, 461. varieties of, 461 — 463. Waste, physical, 1, 2. relation to food, 39. Water, of the egesta, 5. sources of, 9. of bodily combustion, 9, 17, 31, 359, 384. of the food, 52, 64. its uses in the organism, 65, 66. Way, 318. Weber, 143. Wehsarg, 233. Wild animals, flesh of, 277. Will, 306. Wines, 366—382, 389. composition of, 368—373. effervescing, 373. red, 369, 371, 379. white, 369, 379. Zander, 149. THE END. pmiKTBD il IPOTT18WOOD1 — \UE By the same Author. THE DISEASES OF THE STOMACH. 8vo. cloth, 10s. 6d. " Certainly no better guarantee could possibly be given for the faithful discharge of the duties implied in writing- such a treatise than the previous career of Dr. Brinton. His book is one everywhere in- spired by a spirit of truth. It hardly aims at being brilliant or amusing, but it is everywhere readable ; and without tedious- ness, it is earnest, solid, and instructive. Among the numerous works of late years issued upon gastric pathology, it yields to none in importance; and we feel* assured that it will be found to supply a want even in this crowded region of medical litera- ture.— To any one who has arrived, by dint of much reading (or much physicking), at conclusions like these, we recommend Dr. Brinton's book ; and especially its final Chapter on Dyspepsia, as an example how much the spirit of truth and soberness can do for a subject which has been tortured into such an immense variety of forms. — It is unnecessary to enlarge here upon the exhaustive and admirable manner in which Dr. Brinton has treated of the Chronic lUcer, and on Cancer of the Stomach.— The same conscientious care for truth has guided the author through every part of his researches, as is apparent in the ground we have now gone over; and indeed not one sentence or phrase from beginning to end of this work will bear the construction that it was written at random, or without the most serious reflection. "—British and Foreign Medico-Chirurgical Review. "Dr. Brinton's Lectures cannot fail to add to the high reputation already attained by the author— In our notice of his mo- nograph of Ulcer of the Stomach, we gave as a reason for the length to which our remarks had run, that it lessened by one affection 'the wide field for speculation, conjecture, and empiricism, > said by Dr. Abercrombie to be presented by diseases of the stomach ; and we have now to tender him our thanks for having per- formed the same good office for the others." — Dublin Quarterly Journal of Medical Science. " In no separate work published in re- cent years have we met with so clear and exact a statement of the various maladies to which the stomach is liable, of their pathological peculiarities, and the con- ditions which determine the treatment in the several cases.— The rare judgment and discrimination which mark the author's disquisitions into the value of symptoms and pathological phenomena, make the treatise a reliable one for the practitioner, and constitute it, in fact, the reference work on the subject." — Medical Circular. " As one of our first writers upon the structure, functions, and diseases of the alimentary canal, the author of this trea- tise has for some time established his repu- tation. — We have been much pleased with the plain and straightforward remarks on dyspepsia. On the subject of indigestion there is such scope for professional as well as other quackery, that it is peculiarly gratifying to alight upon its discussion conducted with as complete an absence of such foible, as with the presence of scientific rigour. We recommend this work as an honourable addition to the really scientific literature of the day." Lancet. " These Lectures are intended to give a brief but complete account of what is at present known concerning: the Diseases of the Stomach. To the investigation of these maladies Dr. Brinton has devoted a large amount of time and attention. The whole work will fully repay a careful study ; and we therefore heartily com- mend it to our readers." Medical Times and Gazette. " Dr. Brinton comes forward with highly favourable antecedents as an observer of, and writer on, Diseases of the Stomach, and the work now before us will increase his well earned reputation. He has made himself a claim to be looked to as an authority in the subject on which he pro- fesses to instruct.— Dr. Brinton is an accomplished pathologist in stomach dis- eases ; but, what is of equal, or rather of greater importance, he is manifestly a sound rational therapeutist. What reme- dies he employs, he employs with judg- ment, and with a full sense of the difficul- ties which obstruct his efforts ; and, what is of the highest importance, there runs through his therapeutic doctrines an indi- cation to base treatment, as strictly as possible, on Physiology. This character- istic of his practice constitutes an addi- tional claim on his part to our confidence." Association Journal. ■ rIi!iH,. :