Cornell "{University Xibran? OF THE IRcw^orft State College of agriculture ^MQS: &&JML7K, 8101 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003522889 Cornell University Library RM 216.H9 1914 Food and the principles of dietetics. 3 1924 003 522 889 FOOD AND THE PRINCIPLES OF DIETETICS BY ROBERT HUTCHISON, M.D. Edin., F.R.C.P. Physician to the London Hospital ; Physician with Charge of Out-Patients to the Hospital for Sick Children, Great Ormond Street Author of * Lectures on Diseases of Children,' ' Patent Foods and Patent Medicines,' 'Applied Physiology,' Joint-Author of 'Clinical Methods' WITH PLATES AND DIAGRAMS THIRD EDITION NEW YORK WILLIAM WOOD AND COMPANY MDCCCCXIV TO THE STUDENTS OF THE LONDON HOSPITAL TO WHOM ITS CONTENTS WERE FIRST ADDRESSED, AND BUT FOR WHOSE ENCOURAGEMENT IT WOULD NOT HAVE APPEARED IN ITS PRESENT FORM, THIS VOLUME IS DEDICATED BY THE AUTHOR. PREFACE TO THE THIRD EDITION In the present edition the whole book has been thoroughly revised, and the chapters dealing with the use of Diet in Disease considerably enlarged. A new chapter has been added on • Certain Dietetic Cures and Systems.' R. H. December, 1910. PREFACE TO THE FIRST EDITION The contents of this book were first addressed to the students of the London Hospital in the form of a course of lectures about a year and a half ago. The very gratifying reception accorded to these lectures and the almost total neglect of the subject of dietetics in ordinary medical education have induced the author to publish them in their present form. While the book has been specially designed to meet the require- ments of students and practitioners of medicine, it is hoped that it may also prove intelligible and interesting to anyone desiring to acquire some knowledge of foods and the difficult problems of nutrition. In recasting the lectures for publication a large amount of addi- tional material has been used, and no pains have been spared to make the book fully representative of the present state of our know- ledge on the subject of which it treats. A considerable amount of space has been devoted to the patent and proprietary foods, and an effort has been made to deal fairly and honestly with their merits. The great number and variety of these now offered for sale makes this specially necessary. As far as possible original papers have always been consulted, and references to these will be found in the footnotes ; but if, as is only too probable, some important publications have been over- looked, the vast extent of t\e literature of the subject must be taken as the author's excuse. The author feels also that he is under a great obligation to the X PREFACE TO THE FIRST EDITION many able systematic writers on the subject who have preceded him, both in this country and on the Continent, and whose names are too well known to require special mention here. He would like, however, to take this opportunity of expressing his special indebtedness to the work and writings of Professor Atwater and his colleagues in America, who have done so much in recent years to advance our knowledge on the principles of dietetics. The opening chapters, especially, of the present book owe much to the teaching of the American school. To Dr. Leonard Hill and the writer's other colleagues at the London Hospital Medical College he must express his gratitude for much encouragement and useful advice, and to his friends Dr. J. J. R. Macleod and Mr. Robert Tanner he is indebted for the pains which they have bestowed on the revision of the proof-sheets. The illustrations have been drawn by Mr. Danielsson with his usual skill, and the care with which Mr. Archibald Clarke has compiled the index has saved the author much labour. London, October, 1900. CONTENTS CHAPTER I THE NATURE, NUTRITIVE CONSTITUENTS, AND RELATIVE VALUES OF FOODS PAGES Definition of the term ' food ' — Food as a source of building material, heat and energy — The nutritive constituents of food, and their functions — The relative value of foods — Chemical, physical, physiological and economic standards — Mode of applying these — The Calorie — Digesti- bility and ' absorbability ' of foods — The relative cost of foods judged as sources (i) of building material, (2) of energy — What constitutes a ' good ' food - - ... j.jg CHAPTER II THE AMOUNT OF FOOD REQUIRED IN HEALTH Methods of stating the amount of food required — Amount of proteid required daily — Chittenden's results — Amount of potential energy required in diet — -Standard dietaries — Empirical and physiological method of constructing these — Number of Calories and amount of each nutritive constituent required daily — Nutritive ratio in foods — Necessity for a mixed diet — Standard diets — Actual diets of various persons in different conditions of life - ... 20-34 CHAPTER III ON THE INFLUENCE OF VARIOUS CONDITIONS UPON THE AMOUNT OF FOOD REQUIRED Influence of work — Muscular work — The diet of training — Mental work — Influence of rest — Influence of build and shape — Importance of surface- area — Influence of age — Requirements of childhood and old age — In- fluence of sex — Requirements of women — Influence of climate and season— Influence of personal peculiarity — Over and under feeding 35-57 CHAPTER IV ANIMAL FOODS Meat — Physical structure — Chemical composition — Effects of cooking on structure and composition — Digestibility and absorption of meat — Nutritive value and economy — Use of horseflesh and the flesh of dis- eased animals — ' Offal ' — Liver and kidneys — The heart — Blood — Lungs — Sweetbread — Tripe — Brain — Comparative absorption of these — Potted meats — Sausages. ... . 58-75 xi PACES X11 CONTENTS CHAPTER V JELLIES— FISH Gelatin— Isinglass— Sources— Chemical properties, digestibility and nutri- tive and economic value of gelatin and its preparations — Fish— Chemical composition — Fat and lean fish — Digestibility and nutritive and economic value of fish— Caviare— Milt— Marvis— Lobster and crab- Oysters and other shell-fish— Turtle— Frogs - - - 76-89 CHAPTER VI SOUPS, BEEF-EXTRACTS, BEEF-JUICES, BEEF-TEA, AND BEEF- POWDERS Composition of soups— Their nutritive value— Clear versus thick soup— Beef- extracts— History of Liebig's extract— Its chemical composition— Nature and physiological action of the extractives of meat — Value of Liebig's extract — Bovril and kindred preparations— Their claim to be regarded as foods— Beef-juices— Mode of preparation — Home-made beef-juice — Comparison of the patent preparations with this— Nutritive value of beef-juices— Egg-white mixture as a substitute— Leube-Rosenthal's Meat Solution— Beef-tea— How to make it — Its composition and uses — Exaggerated estimate of the value of beef-tea—' Whole beef-tea ' — Beef-powders — Pemmican— Beef-meal— Somatose, etc. — Uses of beef- powders — Conclusions- ... 90-iog CHAPTER VII MILE Proteids— Sugar — Fat, mineral matter, and water of milk— General com- position of cow's milk — Variability of this — Necessity for a standard of composition — Clotting and curdling of milk —Effects of heat — Steriliza- tion and pasteurization of milk — Methods for permanent preservation — Digestibility — Methods of improving this — Absorption of raw and boiled milk — Milk as an intestinal antiseptic— Nutritive value of milk — Not a perfect food — Reasons for this opinion — Economic value of milk — Skim milk as a cheap source of proteid — Milk as a food in disease- Milk 'cures' - - .... 110-131 CHAPTER VIII FOODS DERIVED FROM MILK Wbey — Mode of preparation — Composition — Food value — ' Whey cure " — Cream — Proportion of fat — Devonshire cream — Value of cream as a source of fuel — Its cost — Butter — Preservation— Composition — Digesti- bility and nutritive value — Margarine — History and method of manu- facture—Comparison with butter — Butter versus jam — Butter-milk — Koumiss and kephir — Mode of preparation — Composition and proper- ties of these — Casein preparations — Protene Flour — Sanose — Nutrose — Eucasin — Plasmon — Advantages of casein as a source of proteid — Uses of these substances .... 132-145 CHAPTER IX CHEESE, EGGS, AND EGG SUBSTITUTES Varieties of cheese — Composition — Digestibility — Nutritive value — Eggs — The egg regarded as an undeveloped chick — Composition of shell, white and yolk — Digestibility and absorption of eggs — Patent egg preparations (Ovo, etc.) — Custard-powders - - - 146-150 CONTENTS xiii CHAPTER X VEGETABLE FOODS PAGES Chemical characteristics of vegetable foods as a class — Starch, cellulose, and other constituents of vegetables — Bulkiness of vegetable foods and methods of overcoming it — Mineral constituents — Digestibility of vegetable foods in the stomach and intestine — Difficulties arising from their bulk and richness in cellulose — Absorption of the different chemical constituents of vegetable foods — Proteids not well absorbed — Reasons for this — Nutritive value of vegetable food — Pros and cons of vegetarianism — Disadvantages of a purely vegetable diet — Different methods of supplementing the deficiency in proteid — Relative economy of animal and vegetable foods — Nature's food cycle — Cost of cooking — Summary - - - -' - 160-186 CHAPTER XI THE CEREALS: WHEAT— BREAD Classification of vegetable foods — General characteristics and composition of the cereals — Wheat — Structure and composition of the wheat grain — Milling — Flours — Hovis and Frame Food processes — Bread — Leavened bread — Chemistry of baking — Aerated bread — Baking-powders — Characters of a good loaf — Chemical composition of bread — Whole- meal versus white bread — Vienna, brown, germ and malted bread — Patent breads — Staling of bread — Effects of heat on bread — Biscuits — Rusks- - - - - 187-207 CHAPTER XII BREAD (continued)— OTHER CEREALS Digestion of bread — Length of stay in stomach— Absorption of bread — Reasons for defective absorption of proteids — Absorption of wholemeal bread — Cellulose as a cause of difficulty — Nutritive value of bread — Method of increasing the percentage of proteid — Relative nutritive value of wholemeal and white bread — Cheapness of bread as a food — Other wheat preparations (semolina, macaroni, etc.) — Other cereals — Oats — Maize — Barley — Rye — Rice — Millet and buckwheat — Composi- tion, preparations, digestibility, and nutritive value of these - 208-230 CHAPTER XIII THE PULSES— ROOTS AND TUBERS General composition of the pulses — Their digestibility, absorption and nutritive value — The pea, bean, and lentil — Revalenta — The soy bean — The peanut and butter bean — Roots and tubers — General composi- tion, digestibility, and nutritive value — Potatoes : composition, etc. — Their place in the diet — The sweet potato and yam — Turnips — Carrots — Beetroots — Parsnips — Jerusalem artichokes and onions — Tapioca, sago, and arrowroot - - .... 231-247 CHAPTER XIV VEGETABLES— FRUITS— NUTS— FUNGI— ALG-ffi AND LICHENS Green vegetables — Composition, digestibility, and nutritive value — Fruits — General composition — Sugars of fruits — Mineral constituents — Flavour —■Effects of cooking — Digestibility and nutritive value — 'Food fruits' xiv CONTENTS PAGES and ' flavour fruits ' — Grapes — The ' grape cure ' — The banana— The date, raisin, and fig — Nuts— Composition — Nut butters — Digestibility and nutritive value of nuts — Fromm's Extract — The chestnut and almond — Fungi — Mushrooms versus toadstools — Edible British fungi — Chemical composition of fungi — Their digestibility, absorption, and nutritive value — Algae — Irish moss — Lichens — Iceland moss - 248-269 CHAPTER XV SUGAR, SPICES, AND CONDIMENTS The sucroses and glucoses — Cane-sugar — History, composition, and refining — Beet-sugar — Maple-sugar — Maltose and lactose — Effects of heat on sugar — Treacle, molasses, and syrup — The glucoses — Dextrose — Laevu- lose — Invert sugar — Honey — Sweetmeats — Toffee — Chocolate — Jams — Digestion of sugar — Effects on the stomach — Fermentation — Supposed effects on the teeth — Assimilation of sugars — Alimentary glycosuria — Nutritive value and economy of sugar — Sugar as a muscle food — Spices and condiments — Their r61e in the diet — Mustard, pepper, and vinegar — Sugar as a condiment — Saccharin and dulcin — Saxin and porcherine - - - - 270-287 CHAPTER XVI MINERAL CONSTITUENTS OF THE FOOD Mineral matter as building material for the body — Mineral substances required — Are they sources of energy ? — Amount of them required daily — Calcium — Magnesium — Iron — Sodium and potassium — Common salt — Influence of salt on digestion and metabolism — Phosphorus — The ' phosphates ' — Cerebos salt — Oxalic acid — Sulphur — Chlorine — Iodine — Fluorine and silica — Acidity and alkalinity of foods - - 288-299 CHAPTER XVII WATER AND MINERAL WATERS Water as a tissue-builder — Amount of it consumed daily — Effects of an increase or diminution in the supply — Influence of water on digestion and metabolism — Varieties of water — Water as a source of infection — Sterilization of water — Aerated waters — Classes of these — Natural mineral waters — Uses of aerated waters— Natural versus artificial mineral waters - - .... 300-312 CHAPTER XVIII TEA, COFFEE, AND COCOA Tea: History — Mode of manufacture — Varieties — Black and green tea— Characters of China, Indian and Ceylon teas — How to judge a tea — Chemical composition of tea— Composition of the infusion — Propor- tion of tannic acid and caffeine — How to make tea. Coffee : History — Mode of manufacture — Varieties — Composition — Effects of roasting — Composition of the infusion — ' French coffee ' — Coffee-making. Cocoa : History — Mode of manufacture — Varieties — Chemical composition — Fat — Theobromine — Composition of commercial cocoas — Chocolate. Influence of these beverages on digestion — Digestion and absorption of cocoa — Uses of tea, coffee, and cocoa — Physiological action of caffeine — Food value of cocoa- - * . 3 x 3-336 CONTENTS xv CHAPTER XIX ALCOHOL PACES Ethyl alcohol — Local effects on the tissues — Effects on digestion — Absorption of alcohol by the stomach — Alcohol as a stimulant — Action on the heart and circulation — Influence on body temperature — Influence on meta- bolism — Alcohol as a protoplasm poison and as a sparer of fat — Does it spare proteid ? — Rate of its combustion in the tissues — Alcoholism : acute and chronic — Amount which can be safely consumed daily — Influence of idiosyncrasy — Use of alcohol in health and disease - 337-352 CHAPTER XX ALCOHOLIC BEVERAGES : SPIRITS AND MALT LIQUORS Methods of stating the proportion of alcohol present — Proof spirit — Per- centage — Proportion of alcohol in some common beverages — Spirits — How prepared — 'Silent spirit' — Fusel-oil — Whisky — Definition — Malt whisky — Grain whisky — Potheen — Brandy — Origin and manu- facture — Cognac — Rum — Gin — Liqueurs and bitters — Action of spirits on digestion and metabolism — Special value of ethereal by- products. Malt liquors — Varieties and terminology — Beer — Brewing — Mild and bitter ales — ' Substitute beer ' — Porter — German beers — Com- position of malt liquors — Their action on digestion — Their use as foods — Cases in which they are harmful — Non-alcoholic beers - - 353-371 CHAPTER XXI ALCOHOLIC BEVERAGES (continued) : WINES Definition of the term ' wine ' — Constituents of grape- juice — Fermentation — Changes in cask and in bottle — Constituents of wine — Alcohols — Acids — Sugar — Ethers — Extractives — Glycerine — Varieties of wine — ■ Natural ' and ' fortified ' wines — Claret — Burgundy — Hock — Hun- garian, Italian, Californian and Australian wines — Sherry — Port — Madeira — Marsala — Greek wines — Champagne — Cider and perry — Medicated wines — Non-alcoholic grape wines — Influence of wines on digestion — Action of wines in health and disease ... 372-395 CHAPTER XXII THE COOKING OF FOODS Objects of cooking — Effects of heat on proteids, carbohydrates, and fats- Cooking of meat — Ideal to be aimed at — Boiling — Roasting — Baking- Stewing — Cooking of fish — Frying — The cooking of vegetable foods — The softening of cellulose — Use of acid fermentation, grinding and boiling — Losses in cooking — The taking up of water by vegetable foods — Composition of cooked vegetable foods— Slow cooking — Its advan- tages — Special forms of apparatus for accomplishing it — The bain-marie and its modifications — The Norwegian cooker — Ede's apparatus — The Aladdin Oven — Kanaka cookery ... 396-411 CHAPTER XXIII THE DIGESTION OF FOOD IN HEALTH Digestion in the mouth — Uses of saliva — Digestion in the stomach — Tho stomach as a reservoir— Meals — The secretion of gastric juice — Appetite and hunger — Digestive habits — Acidity of the gastric contents — Diges. xvi CONTENTS PAGES tion of starch in the stomach — Morbid gastric sensations — Movements of the stomach — Functions of the cardiac and pyloric portions — The peristaltic movements of the stomach — Rate of digestion of different foods — Antiseptic action of the gastric juice — The temperature of foods — Absorptive power of the stomach — Digestion and absorption in the intestine — The r61e of bacteria— The faeces — Summary — Influence of exercise and rest on digestion - - - 4 I2 '433 CHAPTER XXIV THE PRINCIPLES OF FEEDING IN INFANCY AND CHILDHOOD : HUMAN MILK Physiological requirements in the diet of infancy — Necessity for proteid and fat — Human milk : its composition and variations — Influence of the period of suckling — Colostrum — Individual differences — Influence of mother's diet on the composition of the milk — Influence of alcohol — Influence of frequency of suckling — Amount of milk required by a child daily — Importance of regular feeding — Digestibility of human milk— Its absorption and nutritive value — Diet of infancy contrasted with that of the adult - 434-447 CHAPTER XXV THE PRINCIPLES OF FEEDING IN INFANCY AND CHILDHOOD {con- tinued) : SUBSTITUTES FOR HUMAN MILK The milk of other animals — Relation between composition of milk and rate of growth — Ass's milk — Human versus cow's milk — Quantitative dif- ferences — Qualitative differences : (1) in nitrogenous matter ; (2) in fat ; (3) in mineral salts — Humanized milk a chemical impossibility — Com- parative digestibility of human and cow's milk in the stomach and in the intestine — Infant feeding with pure cow's milk — Modification of cow's milk : (1) by mere dilution ; (2) cream mixtures of Meigs, Rotch and Biedert ; (3) Soxhlet's sugar method ; (4) humanized milks, Fettmilch ; (5) use of whey as a diluent ; (6) Lehmann's method — Milk prescriptions — Sterilization — Summary - 448-460 CHAPTER XXVI THE PRINCIPLES OF FEEDING IN INFANCY AND CHILDHOOD (con- tinued) : OTHER SUBSTITUTES FOR HUMAN MILK (PEPTONIZED MILK, CONDENSED MILK, PROPRIETARY FOODS) ; FEEDING OF OLDER CHILDREN Peptonized milk— rairchild's peptogenic milk-powder — Condensed milk Method of manufacture and composition — Varieties — Sweetened and unsweetened whole milks — Condensed skim milks — Digestibility of condensed milk — Its nutritive value and economy — Its poverty in fat Humanized condensed milk — Condensed milk as a cause of scurvy Proprietary foods— Defects — Composition — Uses — Summary of rules for infant-feeding — Diet after weaning — Amount of each nutritive ingredient required at different ages — Importance of proteid Nutritive ratio in child and adult — Sources of proteid, fat, carbohydrates and mineral matters — Beverages for children . . 4.61-478 CHAPTER XXVII THE PRINCIPLES OF FEEDING IN DISEASE General rules— Principles of diet in fever — Importance of carbohydrates Fluid diet — Use of milk and need of its enrichment — Intervals at which food should be given— Beverages in fevers— Use of alcohol— Diet in CONTENTS xvii PAGES rheumatic and typhoid fevers — Principles of diet in diabetes — Impor- tance of fat — Quantity of carbohydrate allowable — Classification of cases — Sources of each constituent — Special articles of food in diabetes -—Milk — ' Diabetic milk ' — -Diabetic breads — Special forms of carbo- hydrate in diabetes — Beverages— General plans of diet and arrangement of meals — Diet in complications — Gouty glycosuria - - 479-501 CHAPTER XXVIII THE PRINCIPLES OF FEEDING IN DISEASE {continued) ■The dietetic treatment of obesity— General physiological considerations — Importance of the different constituents of the food — Extent of limita- tion of diet — Banting, Oertel, Ebstein, Hirschfeld and Von Noorden's systems — Relative advantages of these — Particular articles of food in obesity — Arrangement of the meals — Beverages in obesity — Advantages of a dry diet— Fattening diet — Food in convalescence, phthisis and neurasthenia— Dietetics of gout — Rheumatoid arthritis — Diet in Gravel — Oxaluria— Dietetic treatment of scurvy — Dietetic treatment of in- fantile scurvy — Dietetic treatment of rickets — Diet in disorders of the stomach — General considerations — Gastric ulcer — Acute and chronic gastritis — Dilatation of the stomach — Functional dyspepsias— Diet in diseases of the intestines — Diarrhcea — Sprue — Dysentery — Ulcerative and muco-membranous colitis — Constipation — Diet in diseases of the liver — Diet in cardiac disease — Aneurysm — Diet in renal disease — General principles — Acute, subacute and chronic nephritis — Diet in diseases of the nervous system — Diet in diseases of the skin 502.548 CHAPTER XXIX SOME DIETETIC ' CURES ' AND ' SYSTEMS ' Vegetarian and lacto-vegetarian diet — Purin-free diet— Dr. Hare's system — Exclusive proteid diet— Zomotherapy— Salt-free diet— Sour-milk treat- ment - . 549558 CHAPTER XXX ARTIFICIAL AND PREDIGESTED FOODS AND ARTIFICIAL FEEDING Objects of artificial foods — Limits of concentration of foods — Chemical and physiological considerations — Artificial proteid. foods : (1) Undigested, (a) of animal origin, (b) of vegetable origin ; (2) Peptonized — Artificial carbohydrate foods — Malt extracts — Their use : (1) as foods ; (2) as digestive agents — Honey as a substitute — Value of milk-sugar — Artificial fatty foods — Emulsions — Cod-liver oil — Lipanin — Virol — Cremalto — Pancreatic emulsion — Spermaceti — Cream, butter, nuts, etc., as sources of fat — Toffee — Rectal feeding — Absorptive power of the large intestine — Constituents of enemata — Possibility of a reverse peristalsis — Value of adding salt — Limits of usefulness of nutrient enemata — Formulas — Technique — Nutrient suppositories — Subcutaneous feeding — Conditions to be fulfilled by a food suitable for subcutaneous injection — Use of proteids — Serum — Sugar — Fat — Limits of usefulness — Subcutaneous injection of yolk of egg — Gavage and forced feeding - - 559-579 Index ......... 5$° LIST OF ILLUSTRATIONS COLOURED PLATES. FIG. PAGS I. Fuel Value of One Pound of some Typical Foods To face 6 II. Percentage of Nutrients not absorbed in some Typical Foods To fact 10 III. Amount of Energy and Building Material got for One Shilling in some Typical Foods - - - To foci 16 i. Calorie Value of Different Foods 5 2. To Illustrate Influence of Shape on Surface - - -44 3. Amount of each Nutritive Constituent required at different Ages - - - - - - 47 4. Structure of Meat ---.--- j g 5. Composition of Meats - - - - - 63 6. Composition of Raw and Boiled Beef - - - • 65 7. Composition of Fish, etc. - . . - 89 8. Constituents of a Tumblerful of Milk ... 127 9. Percentage Composition of White and Yolk of Egg - 152 10. Actual Composition of an Egg . 153 n. Relative Bulks of Different Diets - . . 167 12. Bulk and Weight of Different Foods yielding the same Amount of Proteid - - 177 13. Carbon Food Cycle ...... 182 14. Nitrogen Food Cycle - 182 15. Longitudinal Section through a Grain of Wheat (Low Power View) 190 16. Section through Wheat Grain (High Power View) - - 191 xix XX ILLUSTRATIONS FIG FAGS 17- Composition of a Loaf - - - • • - - 201 18. Cross Section of a Potato - - . - - 238 19- Composition of a Potato - - - - - 240 20. „ ,, Turnip - - - - 243 21. „ „ Carrot - - - - 243 22. „ ,, Cabbage - - - - 249 23- „ „ Cucumber - - - 250 24. „ ,, Strawberry - - 252 25- „ ,, Apple - - - - 253 26. „ ,, Banana - - - - 257 2 7- , , , , Walnut - - - - 260 28. Shoot of Tea Plant - - - 314 29. Cells of Raw Potato - - - - 402 3°- Cells of a Partially Cooked Potato - - 403 31- Cells of a thoroughly Boiled Potato - 403 32- The Aladdin Oven - . 410 33- Comparison of Nutritive Constituents required by an Adult and an Infant - ■> - * - - 447 FOOD AND DIETETICS FOOD AND DIETETICS CHAPTER I THE NATURE, NUTRITIVE CONSTITUENTS, AND RELATIVE VALUES OF FOODS A food may be defined as anything which, when taken into the body, is capable either of repairing its waste or of furnishing it with material from which to produce heat or nervous and muscular work. I am aware that this definition is open to criticism, as most definitions of the term have been before it, and that it is difficult to refuse to oxygen especially the right to be regarded as a food under the terms of such a description. But for practical purposes the definition may be allowed to stand, and it has the advantage of bringing into prominence the two main functions of food — in the first place, as a provision for the growth and repair of the fabric of the body, and, secondly, as a source of potential energy which can be converted into heat and work. In virtue of the former function, food provides for the conservation of the material of the body ; the conservation of bodily energy is maintained by the latter. Substances which are unable to help in either of these directions may have a useful place in the dietary, but they cannot be truly regarded as foods. Examples of such substances are to be found, as we shall learn later, in tea, coffee, and the extractives of meat. Most ordinary articles of diet are not simple bodies ; they are made up of mixtures of various chemical substances, some of which are of nutritive value, while others are not. The former may be spoken of as 2 FOOD AND DIETETICS the nutritive constituents or ' nutrients,' and may be classified as follows : (i Nitrn^pnnu^ /Proteids, e.g., casein, myosin, gluten, legumin. i. Nitrogenous J Albuminoids, e.g., gelatin. 2 Non-nitroeenous /Carbohydrates, e.g., sugar, starch. 2. JNon nitrogenous | FatS| eg _ o]ive . oil| butter , . /Mineral matters, e.g., sodium, potassium, lime, phosphorus, chlorine, inorganic | Water Any article of diet, even the most elaborate product of the cook's art, can be shown, by chemical analysis, to contain one or more of the members of these different groups ; otherwise it is not a ' food ' at all. The functions of food are fulfilled by the different groups in different measure. The first function, that of building up and repairing the tissues, can be fulfilled by the proteids and by the inorganic constituents, and by these alone. For this purpose proteid, mineral matters, and water are all necessary. None of the three is sufficient by itself. The second function, that of serving as a source of potential energy, is the property of all the organic constituents, although there is a limited sense in which water, and even, perhaps, the mineral constituents, may be regarded as sources of energy too (see p. 288). The comparison of the body to a steam-engine is a rather thread- bare and not altogether accurate analogy, but it is, perhaps, the best that can be found. The building material of food corresponds to the metal of which the engine is constructed, the energy-producers to the fuel which is used to heat the boiler. Where the body differs from the engine is that it is able to use part of the material of its construction (proteid) for fuel also. In regard to the relative values of the organic constituents as energy-producers, physiological opinion has undergone considerable changes in the last fifty years. It used to be supposed, mainly as the result of the powerful advocacy of Liebig, that the proteids were the chief producers of muscular energy, while the carbohydrates and fats merely acted as fuel and maintained the body temperature. We now know that this was a mistaken view. It would seem, indeed, to be to a large extent a matter of indifference to the cells of the body whether they draw their supplies of energy from proteid, albuminoids, 1 In describing the nitrogenous nutritive constituents of foods, I have adhered to the terminology employed in the earlier editions of this book, although the term 'protein' is now largely used instead of 'proteid.' Others employ 1 protein ' as covering the whole group of nitrogenous nutritive constituents ; others use the word ' albuminoids ' where ' proteids ' is employed above, and speak of gelatin and its allies as ' gelatinoids.' The nitrogenous 'extractives' have not been included in the above classification, because they have no nutritive value. FUNCTIONS OF NUTRITIVE CONSTITUENTS 3 carbohydrate, or fat, although probably they can get it more rapidly and easily from the three former than from the latter. We now know also that bodily heat is not a thing apart and requiring to be provided for by itself, but that it is an inevitable accompaniment of cell life. Life and heat are inseparable, and in fulfilling its other functions in the body a cell cannot help producing heat also. Heat, in fact, is a by-product of functional activity (see also p. 48). Hence it is a matter of indifference as far as the cells of the body are con- cerned — not necessarily, be it remembered, as far as concerns the digestive organs — whether we feed a man on white of egg, gelatin, butter, or sugar, always supposing that these are supplied in the proportion of their dynamic equivalents. As regards the manufacture and repair of tissue, however, no such indifference prevails. That can be done by proteid, mineral matters, and water, and by these alone. Even the albuminoids, near though they stand to the proteids, and large though the proportion is in which they enter into the bodily framework, can take no share in tissue formation. This is true, curiously enough, even of the connective tissues, from which gelatin is itself derived. One may therefore classify the nutritive constituents of food, in accordance with their functions in the body, as follows : Tissue-formers. Proteids. Mineral matters. Water. Work and Heat Producers. Proteids. Albuminoids. Carbohydrates. Fats. ? Mineral matters. ? Water. It will be observed that proteids alone are able to fulfil both of the functions of a food. It is this physiological omnipotence which gives to proteids their vast importance in the diet, and justifies the proud title of ' pre-eminent ' which the name implies. Without proteid life is impossible, for the daily wear and tear of tissue must somehow be made good. With proteid, plus water and some mineral salts, life can be healthily maintained for a practically indefinite time, as is proved by the experience of tribes such as the Indians of the Pampas, who live year in year out on nothing but lean beef and water. Such being the uses of foods in the body, the question arises, How is one to judge of their relative value ? By what criteria is one to decide whether any particular article of diet is a good food or not ? The reply is that such a question can only be decided by sub- mitting the food under consideration to these four tests : 4 FOOD AND DIETETICS i. Chemical. — What percentage of each nutritive constituent does the food contain ? 2. Physical. — How much potential energy is it capable of yielding ? 3. Physiological. — How does it behave in the stomach and intes- tine ? Is it easily digested, and to what extent is it absorbed ? 4. Economic. — Are the nutritive constituents which the food con- tains obtained at a reasonable cost ? The methods by which each of these tests is applied must now be considered. 1. The Chemical Test. — Chemical analysis can tell us how much of each nutritive constituent (proteid, carbohydrate, etc.) a hundred parts of the food contain. By the aid of this information we can form an idea of the value of the food as a source of building material or energy. In subsequent chapters the percentage composition of all the chief articles of food will be brought forward in detail, and some types of these will be referred to immediately. 2. The Physical Test. — Ever since Lavoisier showed that the changes which food undergoes in the body are essentially changes due to oxidation, the idea has gathered weight that the amount of heat which a food is capable of yielding on complete combustion may be taken as a measure of its value as a source of energy, for heat and work are convertible terms. Now, the standard of heat production is the calorie, which means the amount of heat required to raise the temperature of 1 gramme of water i° C. This is the small calorie. For measuring the heat value of foods, one employs for convenience the large, or Kilo-calorie — i.e., the amount of heat required to raise 1 kilo (or 1 litre) of water i° C, or, which is the same thing, 1 pound of water 4 Fahr. ; and one writes it Calorie, with a capital letter. All that one has to do in applying this test is to ascertain of how many litres of water the complete combustion of 1 gramme of the food under consideration is able to raise the temperature by i° C. The result gives the value of 1 gramme of the food in terms of Calories. A large number of very careful experiments of this sort have been made in recent years with the aid of the bomb-calorimeter, the results of which are graphically represented in the following diagram (Fig. 1). The suspicion naturally arises that, although these results hold good for combustion outside the body, they may not be equally true for combustion in the tissues. This suspicion is strengthened when one remembers that many of the waste products of metabolism, such as urea, are by no means completely oxidized. The body does not reduce all its fuel to the condition of ashes ; some of it is only charred. Careful observations by Rubner, however, have shown CALORIE VALUE OF FOODS 5 that, if allowance is made for these incompletely oxidized products, combustion inside the body is precisely the same, as far as the amount of energy liberated is concerned, as combustion in an ordinary furnace, and that the heat value of 1 gramme 1 of each of BACON. 8-86 BUTTER. 860 FAT GOOSE. 495 FAT PORK. 412 FAT MUTTON. 403 MAIZE. 3-71 RICE. 3-51 PEAS. 3-31 FAT BEEF. 327 COARSE WHITE BREAD. 303 WHOLE MEAL BREAD. 2-78 | FINE WHITE BREAD. 2-74 CHEESE. 2-4 EGGS. 1-59 LEAN BEER 9 3 POTATOES. 0-9 3 VEAL. 0-75 MILK. 070 CARROTS. 057 APPLES. 0-54 SPINACH. W ORANGES 053 STRAWBERRIES. D32 LETTUCE. * Fig. i.— Number of Calories yielded by the complete Combustioh of one Gramme of Various Foods. the three chief nutritive constituents of food when taken into the tissues is as follows : 2 Proteid .. . . 4' I Calories. Carbohydrates .. 41 „ Fat 93 „ 1 A gramme = 154 grains. A shilling weighs about 5 J grammes. 2 These figures represent the average Calorie value of the nutritive constituents as contained in an ordinary mixed diet, and after allowance has been made for defective absorption and for the excretion of imperfectly oxidized residues by the kidney. They may therefore be taken as indicating the true worth to the body of the different nutritive constituents as sources of potential energy. 6 FOOD AND DIETETICS The white of one egg contains 4 grammes of proteid, a small lump of sugar contains the same weight of carbohydrate, and a thimbleful of olive-oil a similar amount of fat, so that the latter will yield twice as much energy in the body as the white of a whole egg or a small lump of sugar. In the Calorie, then, we have a standard which is as applicable in estimating the energy value of foods as the foot-rule is in measuring length or the ounce in calculating weight. But great as the value of this standard is — and, indeed, it is the only absolute standard by means of which all foods may be compared — one must not over- estimate it. Just as in a furnace some substances, such as anthracite, are ' slow,' and others, such as petroleum, are ' quick ' fuels, so in the human body some of the nutritive constituents seem to yteld their energy to the cells more rapidly than others. Thus, proteids, carbohydrates, and albuminoids seem to be oxidized quickly in the tissues, fats more slowly. And this is not a matter of indifference, for if a rapid output of energy is required, the first group will be more serviceable, whereas a slow production over a long time will be equally well met by fat (see also p. 39). Further than this, the situation in which the energy is liberated must also be taken into account. It rray be a matter of indifference, as far as the heat produced is ooncerned, whether oxidation takes place in the liver or in the muscles ; but as regards the bodily function, of which, as we have seen, the production of heat is but an accompaniment, there is all the difference in the world. The time and the place, in short, have to be considered, as well as the actual amount of the energy liberated. The physical test of a food enables us to judge of the latter ; it tells us nothing of the two former. The method of applying the Calorie standard to a food is very simple. One has merely to multiply the percentage of proteid or carbohydrate which it contains by 4/1, and the percentage of fat by 9'3> to get the total Calories yielded by 100 parts of the food in question. Suppose, for example, that a specimen of milk contains in every 100 grammes 2 per cent, of proteid, 4 per cent, of fat, and 6 per cent, of carbohydrate, then the Calories yielded by that quantity of milk would be as follows : Proteid 2x4-1= 82 Fat 4 X 9'3 = 37'2 Carbohydrate .. .. .. .. .. 6x41 = 24-6 Total Calorie value of 100 grammes'of the milk . . 700 In Plate I. there is represented the number of Calories contained in 1 pound of some typical foods, and the proportions of these Plate I FUEL VALUE OF (ONE POUND OF SOME TYPICAL FOODS., The diagram represents the relative number of Calories obtained from each food in the form- i f proteid green fat -(yellow), and carbohydrate (blue) respectively. The following are the exact figures from which it has been con- structed : Food. Calories as * Proteid. Calories as Fat. Calories as Carbo- hydrate. Total Fuel Value per. Pound. Butter:. . . 18 3,559 none 3,577 Peas 4188 71.7 9825 1.473 Cheese . .. 553 75o none 1,303 Bread . . 130 215 9765 1,128 Eggs . . 232 507 none 739 Beef . . 39i 232 none 623 Potatoes 185 93 341-2 369 Milk . . 67 168 87 322 Fish (cod) 299 16 none 315 Apples . . 9 none 229 238 The number of Calories yielded, by each in- gredient has been calculated from the average percentage composition of the different foods as given in subsequent pages. It is assumed that the whole of each, article is edible, and no allowance is made for defective absorption. asm 5600 3400 3300 3200 3100 3000 2900 2800 2700 2600 2600 2400 2300 2200 2100 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 ,1000 900 800 700 600 500 400 300 200 100 I Fll I I! Ill II ::rr_it"'ir'iPiri[':ic id CO Q 10 1U < CO UJ O r- CO Q_ <-> 03 UJ CD *CL 2. O CO X to 0. Z u- < DIGESTIBILITY AND ABSORBABILITY 1 which are yielded by proteid, fat and carbohydrate respectively. It will be noticed that butter heads the list as far as the total number of Calories yielded is concerned. This is due to the large amount of fat which it contains. In potatoes, on the other hand, the Calories yielded are mainly derived from carbohydrates, while in cheese and beef the total yield is produced by proteid and fat in nearly equal proportion. In other words, as a producer of energy, a pound of butter is worth about three times as much as a pound of cheese, and more than five times as much as a pound of beef ; but as a source of building material both cheese and beef are vastly superior to it. The following table represents the approximate energy- value of one ounce of some standard articles of food. It may prove of assistance in appraising the value of any diet as a source of energy : TABLE OF ENERGY VALUES OF SOME FOODS. Energy Energy Energy Food. ■ Value per Ounce (in Food. Value per Ounce (in Food. Value pel Ounce (in Calories). Calories). Calories). Beef, lean, cooked 60 Butter . 222 Potato, boiled • • 25 ,. fat 93 Plasmon . . . 86 Carrots, cooked . 110 Lamb, cooked .. 62 Cabbage, raw .. 8 Veal ., .. 66 Cheese, American 118 Spinach „ . . IO Pork .. 88 „ Cheddar 134 Fowl .. 80 , , Cheshire "3 Figs, dried .. 92 Duck .. 47 Dutch . go „ stewed .. 50 Stilton . 124. Prunes .. 87 . . 106 Tongue, tinned .. 84 ,, Camembert qi Raisins Sweetbread, raw • 5° , , Cream . 170 Apples, raw . . 14 Liver, raw .. 38 Grapes . . 20 Kidney, raw .. 32 Egg . . (in one) 70 Bananas . . .. 28 Calf's-foot jelly • 25 Flour, white . . 100 Almonds . . • J 74 Cod, raw .. . . 20 Bread, • 7° Walnuts . . . 182 Salmon, raw . 60 ,, wholemeal 62 Hazel-nuts . 190 Halibut „ • 35 Biscuits . . . 112 Eel • 36 Rusks . 98 Sugar • "5 Herring „ • 4 1 Marmalade or jai n 98 , , smoked • 85 Oatmeal . . . 130 Haddock, raw . 20 Rice . 98 Beer, bottled • 17 , , smoke 1 27 Stout . 20 Mackerel, raw . 40 Sago . 96 Lager beer • 14 Turbot • 55 Tapioca . . . 96 Hock . 18 Sardines in oil . 80 Arrowroot . . . 96 Claret . 18 Oysters • 15 Macaroni . . . 100 Port Sherry • 41 • 38 Milk . 20 Peas (dried), raw . 92 Spirits • 83 Cream (45 %) . . 126 „ (green), „ 22 Owing to the great variations in the composition of foods the energy values given in this table are merely approximative ; in the case of some foods, such, for example, as bacon and ham — the variations are so great as to render any state- ment as to the average value useless. In every case the value of the edible 8 FOOD AND DIETETICS portion of the food is alone represented. So far as possible, the energy value has been calculated for the food as prepared for the table, but in many instances, owing to the elaborate methods of cooking employed, this has been found im- practicable, and the value of the raw food is given instead. (For further infor- mation on this point see 9 a paper by Schwenkenbecher, ' Die Nahrwerthberech- nung tischfertiger Speisen,' in the Zeitsch. f. Physik. mid Diat. Therapie, iv., 1901, p. 380.) 3. The Physiological Test. — It is not enough that a food should contain a considerable proportion of proteid, carbohydrate and fat, and should, be capable of yielding energy on oxidation. It must also be of such a nature that it can be easily digested in the stomach, and more or less completely absorbed into the blood. Such sub- stances as sawdust, petroleum, and hoof-parings might pass the chemical and physical tests easily enough, but they are of no use in the body, for they cannot be digested and absorbed. For this reason the behaviour of a food in the stomach and intestine must be reckoned with before any opinion can be pronounced as to its value in the diet. In studying this subject, one must distinguish very clearly between the meaning of the term ' digestibility ' in its popular sense and that attached to it by physiologists. When one speaks of a food as being ' indigestible,' one ordinarily means that it is a food which is apt to produce feelings of pain and discomfort in the stomach. When a physiologist uses the term, he usually means that the food to which it is applied is one which is only imperfectly absorbed into the blood. Cheese is an indigestible food in the former, and green vegetables in the latter, sense. To avoid confusion, it is better to adhere to the popular usage of the expression ' digestibility,' and, if one may use a rather ugly word, to employ the term ' absorbability ' to indicate the completeness with which the constituents of a food can pass from the intestine into the circulation. 1 By a digestible food, then, I mean one which is disposed of by the stomach with little trouble, and without producing any feelings of discomfort or pain. The only absolute criterion of the digestibility of a food in that sense is the length of time which it has to remain in the stomach before it is fit to be passed on into the intestine. ■ The shorter the time a food needs to stay in the stomach, the greater is its digestibility ; and the longer the period which must elapse before it can pass on into the intestine, the more indigestible it is. In a subsequent chapter we shall have occasion to study the results of a large number of exact experiments which have been 1 In this nomenclature ' digestibility ' would correspond to the German erirag- iarkeit, and ' absorbability ' to ausnutzbarkeit. ABSORPTION OF DIFFERENT FOODS g performed to ascertain the length of time which different foods remain in the stomach — experiments, that is to say, on the com- parative digestibility of foods. I would only point out hei e some of the factors which are of importance in determining the length of time required in any particular case. It must be borne in mind that one of the chief duties of the stomach is to reduce the food to a fluid or semi-fluid condition. The more difficult the process of solution is, the longer must the food remain in the stomach. Now, bulky foods, and those of a dense and firm consistency, or which contain a large proportion of solid matter, will take longer to dissolve, and will consequently remain longer in the stomach than foods of opposite properties. Obviously, then, foods of such a character may be regarded as comparatively indigestible. In addi- tion to these factors, certain others must be taken into account, such as the temperature of the food, the proportion of fat which it contains, and the presence or absence of substances in it which are capable of exciting the secretion of the digestive fluids. All of these will be fully considered later on. Before leaving the subject, mention must be made of one other quality of foods which seems specially to affect the stomach, and which, for want of a better term, is commonly called their satis- fying power. It is a matter of common knowledge that some foods appease the appetite and allay the feelings of hunger longer than others. Such foods are said to be ' satisfying,' or, to use a slang expression, ' stodgy.' What it is which confers this quality upon some foods rather than others is not perfectly clear ; but there is reason to believe that it depends to some extent upon the amount of fat which the food contains. Foods rich in fat are more satis- fying than others. It is believed to be for this reason that eggs possess the quality under consideration in no ordinary degree. Other properties, such as the amount of solid matter to be digested and the bulk of the food, no doubt also play a part in producing the feeling of ' satisfaction ' ; but whatever the explanation of the quality is, it has certainly to be reckoned with in estimating the value of a food from the stomach point of view. Absorbability. A large number of experiments have been performed in recent years in order to ascertain the degree to which the different con- stituents of various foods are absorbed into the blood. Most of these experiments have been carried out on the Continent, but a 10 FOOD AND DIETETICS few have also been made in America. The results are summarized (in round numbers) in the following table, constructed from the figures of Rubner 1 and Atwater 2 : ABSORBABILITY OF DIFFERENT FOODS. Per cent, absorbed. Dry Substance. Proteid. Fat. Carbo- hydrates. Milk Margarine Fine wheat bread Decorticated whole wheat bread Rice Beans French beans Potato puree (in small quantities) Cabbage Beetroots 95 95 91 95i 88 93 95 96 99 82 85 8o£ 85 79 Practi- cally all Practi- cally all 88 to 100 81 to 100 69i 89 81 84 82j 70 8o£ 70 8i£ 61 72 7g to 92 96 93 to 98 98 96 ? ? ? ? ? ? ? ? 99 924 97 97i 99 96! ? Practi- cally all 92* 82 82 . The method of experiment consists in analysing the food to be investigated, and then ascertaining, from an examination of the faeces, the proportion of its proteid, carbohydrate and fat which escapes absorption. A little consideration will show that there is here a source of fallacy. The faeces consist not merely of the remains of unabsorbed food, but also, and to a very considerable extent, of the residues of the digestive juices and the debris of epithelial cells. In the case of the nitrogen and fat of the fasces, at any rate, one cannot tell what proportion is derived from the one source and what from the other. So uniform, indeed, is the percentage composition of the excreta under all diets that some writers 3 prefer to speak of foods as large or small fasces-producers, rather than as being capable of incomplete or complete absorption. After all, the matter is one of academic rather than practical interest. The important point is that on some diets more nitrogen and fat are excreted from the 1 Leyden's ' Handbuch der Ern'ahrungstherapie,' 1897, i. 115. 2 ' The Chemical Composition of Food Pishes,' Washington, 1891, p. 825. 8 See Prausnitz, Zeitsch. /, Biologic, 1897, Bd. xxxv., p. 287. .Plate 11 PERCENTAGE OF NUTRIENTS NOT ABSORBED IN SOME TYPICAL FOODS 100 95 90 85 80 75 70 65 60 55 50 45 ABSORPTION OF FATS AND CARBOHYDRATES n body than on others. Whatever the source of these, they are equally indicative of loss to the body. One is therefore quite justified in representing the loss as if it represented food material .unabsorbed. In the accompanying diagram (Plate II.) there is shown the percentage of each nutritive constituent which is un- absorbed in some typical foods. It will be well to consider each constituent separately. i. Absorption of Proteids. — One of the first points which arrest the attention on looking at- the diagram is that, of the three chief nutritive constituents, the proteids are the least completely absorbed. Whether this is quite an accurate way of stating the case, whether one should not rather say that foods differ more in regard to the waste of nitrogen which they cause than in any other respect, is, as has been shown, a matter of indifference. The fact remains that with some foods much nitrogen is excreted in the faeces, with others little. Closer inspection will show that in this respect foods may be divided into two groups. On a purely animal diet (milk, eggs, beef) there is but little nitrogen lost ; whereas with vegetable foods (carrots, potatoes, peas, etc.) the waste of nitrogen is very consider- able, amounting in the case of carrots to nearly 40 per cent, of the total proteid consumed. The reason for this loss of proteid on a vegetable diet will be considered later (p. 169), but it must be pointed out here that the smaller the amount of nitrogen a food contains, the greater is the apparent loss of it in the faeces, for the higher is the ratio of the nitrogen derived from the digestive juices to that in the food. This explains, to some extent at least, the great apparent loss of proteid in such foods as carrots and rice. 2. Absorption^/ Fat. — Compared with the proteids, fat is apparently very completely absorbed. This probably means that the residue of the intestinal juices contains almost no fat ; hence nearly all of that which appears in the fsces is derived from the unabsorbed fat of the food. In the case of most of the vegetable foods, the amount of fat which they contain is so small that its absorption cannot be accurately estimated. Regarding the absorbability of fat, one generalization can be made with a fair amount of certainty, and it is this : the lower the melting-point of the fat, the more completely is it absorbed. The explanation of this, of course, is that a fat which is fluid at the body temperature is more easily taken up into the blood than one which remains more or less solid. The following are illustrative examples : 12 FOOD AND DIETETICS P , Melting- Percentage point. umbsorbed. Butter 37° C. 2j Bacon 48 C. 8 Mutton-fat 52° C. 10 The total amount of fat which can be absorbed in one day is a matter of some interest. It has been found by experiment that 150 grammes (about 5^ ounces) can be absorbed without appreciable loss. Above this point the waste increases considerably, but even when twice that quantity is taken the loss is less than 45 per cent. The practical deduction from these facts is that one need have no hesitation in ordering a patient, say a diabetic, to consume } pound of butter every day. There is no likelihood of this quantity sur- passing the absorptive powers of the intestine. 3. Absorption of Carbohydrates. — As is clearly shown in the diagram, the carbohydrates are more completely absorbed than any other nutritive constituent of the food. Sugar probably never fails to enter the blood to the last grain, and even starch only reappears in the faces when taken in a form specially difficult of absorption, such as in green vegetables or in coarsely divided masses. Hence it is that foods which consist mainly of carbohydrates, such as rice leave, on the whole, less solid residue in the intestine than any other, animal foods not excepted. In other words, the statement sometimes made, that vegetable are less perfectly absorbed than animal foods, is not universally true, although it may hold good in the majority of cases. Seeing that a given weight of fat represents about two and a quarter times as much energy as an equal weight of proteid or carbohydrate, it is evident that the loss to the body of a given amount of fat through non-absorption is of more importance than an equal loss of any of the other nutritive ingredients. For this reason it is perhaps more instructive to represent the percentage of the total Calories which a food contains which are lost in this way, rather than to give, as has been done above, the actual loss of each constituent. Adopting this plan, it will be found that the loss in some typical foods is as follows : p 00 g Percentage 0/ Calories lost through Non-absorption. Rice 26 Milk 4-4 Bread . . . . . . . . . . 45 Meat .. .. 55 Potatoes 68 Carrots 202 (Rubner.) BALLAST 13 It will be observed that from this point of view rice and milk are much more economical foods than potatoes and meat. Absorption of a Mixed Diet. Most of the above experiments have necessarily been made when the subject of them was living upon a single article of diet only. But in ordinary life most people live upon a mixed diet, and it becomes necessary to inquire to what extent absorption goes on under these circumstances, and how the presence of one food in the intestine affects the absorbability of another. In general terms it may be said that the constituents of a mixed diet are better absorbed than those of any one article of food when taken by itself. This comes out very clearly in some observations recorded in America. An average of eleven experiments 1 on ordinary mixed diet gave the following results : Organic matter 957 Proteid 926 Fat .. .. .. .. .. .. 94-4 Carbohydrate 97-1 In another experiment 2 the diet consisted of beef, eggs, bread and butter, milk, potatoes and fruit. The following were the percentages absorbed : Proteid 949 Fat 969 Carbohydrate . . 98-9 In a third set of experiments 3 the subject lived upon beef, white and brown bread and butter, milk, oatmeal, potatoes and fruit, and absorbed of their constituents the following amounts : Proteid 913 per cent Fat . . . . . . . . . . . . 95-9 ,, Carbohydrate . . . . . . . . 97 7 „ The absorption of proteid is more favourably influenced by the presence of a mixture of foods than is that . of any other con- stituent. This is probably to be explained by the fact that the production of organic acids from the carbohydrates of a mixed diet exerts a restraining influence upon the destruction of proteids in the intestine by putrefactive bacteria.* Thus, it has been found by actual experiments that the constituents of bread and milk are better 1 Wait, United States Department of Agriculture, Bull. 53. a Ninth Annual Report, Storrs Agricultural Experiment Station, p. 179. 8 Ibid. A very complete summary of all the existing experiments upon the absorption of foods will be found in Bull. 45, United States Department of Agriculture, 1898. 4 The fatty acids liberated from neutral fats may perhaps act in a similar way. 14 FOOD AND DIETETICS absorbed when these foods are taken together than when either is consumed alone. 1 The same was found by Rubner to hold good for a mixture of milk and cheese, as compared with either of these articles taken separately. Taking the general results of all experiments, it has been calculated that the following proportions of nutritive constituents will be absorhed from a mixed diet 2 : Proteid. Fat. Carbohydrates. Animal foods . . . . 98 per cent. 97 per cent. 100 per cent. Cereals and sugars ..85 ,, 90 „ 98 „ Vegetables and fruits . . 80 „ 90 ,, 95 „ Ordinary mixed diet .. 92 „ 94 J „ 98 J ,, The following table 3 represents the average ' physiological value ' of some diets after allowing for losses from defective absorption and the excretion of incompletely oxidized residues, such as urea : Percentage of Total Calories Diet. available for Purposes of Nutrition. Human milk . . . . 91 -6 Cow's milk (infant) . . . . . . . . . . 907 „ „ (adult) 89-8 Mixed diet, rich in fat . . . . . . . . . . 90-4 „ „ poor in fat .. .. .. .. .. 89-3 Bread .. .. .. .. .. .. .. 82-1 Potatoes .. .. .. .. .. .. .. 92*3 Meat 76-8 It may be asked whether it is to be regarded as an advantage in a food that it is completely absorbed. The reply would be that a food which leaves a moderate amount of unabsorbed residue is certainly preferable. The intestine seems to require a certain amount of ballast— probably to act as a stimulus to its peristalsis. If herbivorous animals, such as rabbits, are fed upon a diet which leaves little or no residue, it has been found that they suffer from affections of the intestine which may even prove fatal, whereas such effects can be avoided by adding to the food any material which leaves behind an unabsorbed residue. Even in the case of man, who has a considerably shorter intestine, it is observed that a diet which is practically completely taken up into the blood, such as one composed exclusively of meat, is prone to be accompanied by intestinal disturbances. On the other hand, a diet which leaves 1 Bull. S3, United States Department of Agriculture, p. 44, 1898. 2 Atwater, Storrs Agricultural Experiment Station, Ninth Annual Report, p. 187, 1896, and Bull. 117 Off. of Experiment Stations, U.S. Dept. of Agricul- ture, 1902. 3 Rubner, Zeitsch. f. Biologic, 1901, xlii., p. 261. BALLAST 15 behind a very large residue is not only wasteful in an economic sense, but demands for its manipulation and evacuation an undue amount of muscular and nervous energy on the part of the intestine. This, as we shall see later, is one of the drawbacks to a purely vegetable diet. In conditions of disease *it may be necessary to take advantage of the behaviour of different foods in respect of absorption. If peristalsis is exaggerated, as in diarrhoea, one does well to select those foods which are most completely absorbed, e.g., rice, minced meat, or milk. In the opposite condition of diminished peristalsis and constipation, it is important to supply the intestine with a larger amount of ' ballast ' than usual, and such foods as green vegetables and whole-meal bread most perfectly fulfil the requirements of the case. Before leaving this subject two questions present themselves for consideration. The first is, may there not be individual differences in absorptive capacity ? In other words, may some persons not extract the nutritive constituents from their food more thoroughly than others ? It might be supposed that in this way some anomalies in dietetics would find an easy explanation, such, for example, as the unequal amounts of fat and flesh laid on by different individuals on the same diet. Tempting though this explanation is, it must be admitted that there are no exact observations in favour of it, but rather the reverse. It has been found, for example, that persons who have been accustomed to a purely vegetable diet for years absorb its constituents no better than those to whom such a regimen is a comparative novelty (see p. 179). The large number of observations which have been made on different individuals with the common articles of food have also failed to elicit any striking disparity in the degree to which absorption takes place, and even where the intestines are considerably deranged by disease there is a remarkable tendency for the ordinary degree of absorptive capacity to be maintained. The second question which arises is this, Granted that the con- stituents of two foods are absorbed with equal completeness, may it not be true that the process of absorption demands a greater expenditure of energy in the one case than the other ? Undoubtedly it is so ; or, rather, the amount of energy which requires to be expended in order to reduce a food to a state in which absorption is possible may be greater in one case than in another. It has been found, for example, that for the same amount of proteid actually absorbed three to four times as much energy has to be expended in the case of bread as in that of milk. This is one of the advantages 16 FOOD AMD DIETETICS of a milk diet. Its absorption demands but little intestinal labour. That such labour is by no means inconsiderable is shown by the fact that, of the total amount of energy supplied to the body by a diet of bread and butter, fully 5 per cent, is expended merely in its digestion and absorption. 1 It seems likely that in future more attention than hitherto will require to be paid to this aspect of digestion. Reviewing the results yielded by the application of the physiological test to foods, it must be admitted that they are of great value. Had it always been carefully applied, certain common dietetic fallacies would never have gained the wide prevalence they at present enjoy. Examples of these are the supposed superiority of whole-meal to white bread (p. 216), and the erroneous notion that the fungi might, if properly taken advantage of, prove a cheap and valuable source of food. A more egregious instance is to be found in the idea that petroleum can act as a substitute for cod-liver oil. I have elsewhere 2 advanced experimental evidence to prove that petroleum cannot be absorbed by the human intestine. It is thus ruled entirely out of the class of true foods by the application of the physiological test, even if it were, as it is not, admissible to that class in virtue of its chemical properties. Maly has aptly compared foods to ore, and their nutritive con- stituents to the metal which the ore contains. Just as the metal has to be extracted from the ore before it is of any use, so, by the pro- cess of digestion, the nutritive constituents have to be extracted from a food before they can be absorbed. The chemical test tells us how much metal is present in the ore ; the physiological test tells us whether or not the body is capable of extracting it. 4. The Economic Test. — Having ascertained the richness of a food in nutritive constituents, the amount of energy which it is capable of yielding, and the readiness with which it can be digested and absorbed, we have still to inquire whether the nutriment which it affords is obtained at a reasonable cost. For this we require an economic test. The simplest way of applying such a test is to find out how much energy (in Calories) and how much building material (in proteid) one can get for a particular sum when invested in the food under consideration. In the following diagram (Plate III.) the results of the application of this test to various typical articles of diet are set out. Looking first at the energy (Calories) obtained, one sees that bread leads the way, a shilling invested in bread yielding 1 Pawlow, 'Die Arbeit der Verdauungsdriisen,' p. 89. 2 British Medical Journal, 1899, i. 724. Calories 10.500 Plate in AMOUNT OF ENERGY-(Calories) & BUILDING MATERIAL (Proteid) 60T FOR ONE, SHILLING I IN SOME TYPICAL FOODS Grammes 600 iu X "2 £ 2 § uj ej It- LU CO RELATIVE COST OF FOODS 17 10,764 Calories, or more than three times as much as is obtained for the same sum in milk, and more than ten times as much as can be got in the form of beef. In the matter of building material, on the other hand, peas come first, a shilling's worth containing 572 grammes of proteid, or fully twice as much as can be obtained in cheese for the same expenditure. In the form of eggs or beef building material is even more costly, the former being more than eight, and the latter more than five, times as expensive a source of proteid as peas. Taking the results as a whole, it will be observed that the vegetable foods are far cheaper than the animal foods, whether one uses them as sources of energy or of building material. This is one of the strongest arguments in favour of vegetarianism. Of the various nutritive constituents of food, carbohydrate is by far the cheapest. The reason is that carbohydrates make up the chief bulk of most vegetable foods, and these are, as we have just seen, considerably cheaper than the foods of animal origin. The further question, why vegetable foods are cheap, will be considered in another chapter (p. 181). Compared with the carbohydrates, proteid and fat are very ex- pensive constituents of foods, fat, perhaps, especially so. ' It is 3 remarkable fact,' says Buckle, 1 ' and one to which I would call . particular attention, that owing to some more general law, of which we are ignorant, highly carbonized food is more costly than food in which comparatively little carbon is found.' The ' more general law ' of which he speaks is really the same law by- which animal foods are dearer than vegetable. By far the larger part of the fat in our diet is derived from animal sources. The dearness of fat is un- fortunate, and is not uncommonly a source of trouble in practical dietetics. One might mention, as an instance, the difficulty which a diabetic, who has at the same time the misfortune to be a poor man, finds in providing himself with a diet suited to his disease. The same remark applies, though less forcibly, to proteid. The practical importance of having an economic test for foods is the more convincingly felt when one realizes that the market price of a food is no indication of its real money value. In the market one pays for flavour and rarity, not for nutritive qualities. It is the demands of the palate which cost, not those of the stomach, and we pay for esthetic qualities in foods just as in dress we pay for ' cut ' and ornament, not for material to keep us warm. Suppose, for example, that one wishes to buy a pound of fish. If sole is the 1 Buckle, ' History of Civilization,' vol. i., p. 62. 2 18 FOOD AND DIETETICS form selected, it may cost is. 6d. ; haddock would yield quite as much nutriment for 4d. ; i.e., in the former one is paying 4d. for nutriment, and is. 2d. for other qualities. Or take the case of arrowroot. A pound of the best Bermuda costs 2s. 9d., St. Vincent only 3d. or 4d. Yet both are, in a chemical sense, merely starch, and physiologically their behaviour is identical. It is the same with cheese. A pound of Stilton costs is. 2d. The same amount of nutriment can be had in Dutch or American for 6d. These examples might be multiplied indefinitely, but they are sufficient to show that the maxim 'cheap and nasty' does not hold good for foods. I should be sorry to deny that aesthetic considerations should not be taken into account in selecting a dietary. It may be true that the sense of taste is as much worth cultivating as that of sight or hearing, but if one resolves to go in for luxury it is well to do so knowingly, and not imagine that one is nourishing the body while merely pleasing the palate. To students and practitioners of medicine, a knowledge of the economic value of foods is of special importance. It is frequently our duty to see that the diet of a patient is enriched in special direc- tions, most commonly, perhaps, in that of proteid or fat. There is no use in recommending to a poor man chicken and cream. He cannot afford to buy them. It is worth while to remember, however, that the cheapest sources of building material are skim milk, some forms of fish (e.g., herring or salt fish), cheese, the cheaper cuts of meat, and, if his digestion be good, the pulses, while the most economical forms of fat are margarine and dripping. These articles are within the reach of almost everybody. To the poorer classes, too, such knowledge is of special value. It must be remembered that, of the wages which a working man receives, fully 50 per cent, must be spent on food alone, and that the poorer a man is the larger is his proportionate expenditure on this item. And yet the pathetic thing is that it is just this class of the community whose food purchases are apt to be the most irrational. There is room here for popular instruction. 1 Of two other points which concern the economy of foods no mention has been made ; I refer to ' waste ' and the cost of cooking. Of avoid- able waste there is no need to speak, though in this country at least we have much to learn in that respect from some of our Continental neighbours. By unavoidable waste one means that a considerable 1 See 'Family Budgets' (London: P. and S. King), 1896, and Oliver, 'The Diet of Toil, and its Relation to Wages and Production,' a paper read at the Congress of Hygiene and Demography, Buda-Pesth, September, 1894. RELATIVE COST OF FOODS 19 proportion of much food as purchased is not in an edible form ; I refer to such things as the skin and skeleton of fish, the bone of meat, and some parts of green vegetables. In ordinary cuts of meat the unavoidable waste may be reckoned as about 15 per cent. ; in fish it may sometimes rise as high as 70 per cent. This must certainly be taken into account in making purchases of food. In the diagram (Plate III.) allowance has been made for these waste matters, but no account has been taken of the cost of cookery. This is a matter which it is exceedingly difficult to estimate, as so much depends upon the cook, but the general value of the results is not seriously impaired by the omission. In conclusion, I would point out what the reader has no doubt already perceived for himself, that it is by no means an easy matter to pronounce an opinion upon the value of a food offhand. Each test must be applied in turn, and it is only upon those foods which come satisfactorily out of all of them that a favourable verdict can be pronounced all round ; in other words, that is only to be adjudged a ' good ' food which contains an ample proportion of nutritive con- stituents, which is easily digested and absorbed, and which can be obtained at a reasonable cost. The chief justification of a mixed diet is to be found in the fact that no one food comes up to all these requirements. In what respects individual foods fail will be shown in subsequent chapters. [20 ] CHAPTER II THE AMOUNT OF FOOD REQUIRED IN HEALTH. It was pointed out in the last chapter that the function of food is a double one : (i) to furnish material for bodily growth, and for the repair of the daily waste of the tissues ; (2) to provide a supply of potential energy for expenditure in the form of heat and work. We have now to consider how much food must be supplied daily if these functions are to be efficiently carried out. It will be convenient to consider the two divisions of the problem separately, and to discuss in the first place how much ' building material,' in the second, how much potential energy, is required daily. The building material in the diet consists, as we have seen, of proteid, mineral matters, and water. I propose to defer to a later chapter the consideration of the amount of mineral matters and water which the diet should contain, and to confine myself at present to the discussion of the question : How much Proteid is required Daily ?— It may be stated at once that to this question no conclusive reply has yet been furnished by physiology. This is unfortunate, for the problem is one the import- ance of which it would be impossible to exaggerate. It is, indeed, one of the most fundamental problems in the physiology of nutri- tion, and until it is finally solved dietetics cannot fairly claim to rank as an exact science. In the succeeding paragraphs the results of the efforts which have been made to settle the question will be briefly set out. An ordinary man on a freely- selected diet is found to excrete about 20 grammes of nitrogen daily. It may be assumed that all of this should be supplied in the form of proteid, and as proteid contains about 16 ner cent, of nitrosen it is obvious that AMOUNT OF PROTEID. REQUIRED 21 125 grammes of the former will be able to supply 20 grammes of the latter. As a matter of fact, that is the generally accepted standard for the amount of proteid required daily, but it is by no means an absolute one. The reason for this is that the body is able to establish an equilibrium on very various quantities of proteid. The typical man referred to above excretes 20 grammes of nitrogen daily, merely because he consumes that amount in his daily food. Had he consumed 15 grammes, he would only have excreted 15 grammes, and if his consumption had risen to 25 or 30 grammes or higher, his excretion would still have kept pace with it, for the body is unable to store up any surplus of proteid, as it does of carbohydrate or fat. It is this tendency for the amount of nitrogen excreted to be -exactly equal to the amount consumed which physi- ologists call the establishment of nitrogenous equilibrium, and it is evident that such equilibrium can be established on any quantity of proteid which the digestive organs are capable of dealing with. The question, therefore, is, What quantity is best ? To this, it may be at once confessed, no absolute reply can be given. When one recollects that the chief function of proteid is to keep in repair the tissues of the body, one is tempted to suppose that all that is necessary is to consume enough for that purpose. Anything above that, it might be thought, would be mere extravagance — the luxus consumption of the older school of physiologists. But how to ascertain that bare amount ? The reply at once suggests itself that in the amount of nitrogen excreted during starvation there will be found a measure of the amount which just suffices to keep the tissues in repair. A man who has been starving for some time excretes about 4 to 5 grammes of nitrogen daily, 1 but it is found that if merely this amount is supplied in the food it is not sufficient to establish equilibrium. Indeed, the smallest amount of nitrogen on which it is possible to establish equilibrium is found to be from three to four times the amount excreted during hunger. Should we, then, attempt to live on this minimum ? This is a very difficult question. Remembering that, although the chief use of proteid is to build up and repair the tissues, yet every gramme of it is also capable of supplying to the body 4*1 Calories of energy (p. 5), it is evident that the problem which confronts us can be stated in another way. Should we make use of proteid merely as building material, relying upon carbohydrate and fat as our sources of 1 For observations on fasting men, see 'A Digest of Metabolism Experiments," United States Department of Agriculture, Bull. 45 (revised edition), p. 87, 1898. a FOOD AND DIETETICS energy, or should we also take advantage of its capability of pro- viding for heat and work ? Before finally replying to this question another factor in the problem must be presented. We know from physiological experi- ment that the greater the quantity of carbohydrate and fat which is supplied along with proteid, the less does the latter tend to be wasted in supplying energy, and the more of it there is available for the higher purpose of keeping the tissues in repair. The fat and carbohydrate are sacrificed instead of the proteid. This is what physiologists mean when they describe fats and carbohydrates as proteid sparers. But it is almost impossible so to arrange matters that all the energy shall come from fat and carbohydrate, and so leave all the proteid free for repairing the fabric of the body. And for this reason : the cells of the body may be supposed to be bathed with lymph containing in solution particles of proteid, fat, and carbohydrate derived from the blood. These particles are attacked by the cells and oxidized, heat and energy being liberated in the process. But the cells do not seem to be able to attack each of these constituents with equal ease. Of the three constituents mentioned, proteid is most easily broken down, then carbohydrate, fat least easily of all. If, then, the three are present in equal pro- portion, there will always be more of the proteid attacked than of the others. But if, on the other hand, carbohydrate and fat are present in great excess, they assert themselves by their mere ' mass influence,' and exclude many of the proteid particles from ever coming into contact with the cell at all — crowding them out, so to speak — and so sparing the proteid from destruction. It is almost impossible, however, to get the three chief nutritive constituents into the neighbourhood of the cell in such proportions that none of the easily-attacked proteid is used up. By giving abundance of carbo- hydrate this object can be more easily effected than by fat, for, as we have seen, the cells have less difficulty in coping with the former than the latter. Gelatin is an even more efficient sparer of proteid (see p. 77)- Hence it is that those foods which contain a very large excess of carbohydrate along with a moderate proportion of proteid, and in which both are absorbed and reach the cells at about the same rate — a most important point — will be the foods on which least proteid is likely to be wasted and the largest fraction of it reserved for tissue repair. In other words, these will be the foods to have recourse to if one wishes to preserve nitrogenous equilibrium on a minimum amount of proteid. In accordance with this, it has been found that nitrogenous equilibrium can be maintained on 1,500 AMOUNT OF PROTEID REQUIRED 23 to 1,600 grammes of bread containing only 104 grammes of proteid, on 800 grammes of maize with 74 of proteid, and on 3,080 grammes of potatoes in which the total proteid amounts to not more than 54 grammes ; and yet all of these quantities are sufficient to supply 3,000 Calories daily (Rubner). Despairing of finding any reply to the question What is the proteid optimum ? on purely scientific grounds, physiologists have had recourse to two other methods of attacking the problem — viz., (1) by estimating the amount of proteid contained in the freely- chosen diet of an average man doing a moderate amount of muscular work ; (2) by testing experimentally the point to which the amount of proteid in the diet can be reduced without any impairment of the health and efficiency of the individual resulting. (1) The former of these methods was first employed, and upon its results the accepted dietary standards have hitherto been based. Any estimate of its validity, however, must depend upon the number and extent of the data upon which its conclusions are founded, and upon one's belief in the instructive wisdom of mankind in matters of food. To the trustworthiness of its data, I think, no reasonable objection can be taken. A very large number of analyses of freely- chosen diets in various parts of the world have now been made (see p. 32), and they show, with a remarkable degree of unanimity, that the standard of proteid adopted has been almost invariably something above 100 grammes. Where the standard falls below this the shortcoming is explicable either on the ground of insufficiency of means to purchase the average diet, or, as in the case of some Asiatics, by reason of the subject being an individual of small body- weight. The objection, on the other hand, that this standard, though nearly universal, is not necessarily wise, cannot be met so easily, and its force will depend upon the relative weight which one attaches to instinct and to greed respectively, in determining the dietetic habits of mankind. For his own part, the writer is bound to point out that there is at least strong a priori reason for the belief that, in matters of diet, what has been adopted semper et ubique et ab omnibus is fundamentally right, especially when one remembers that proteid is one of the more expensive nutritive constituents of the food, which it must often involve a good deal of struggle and sacrifice to obtain. (2) Although certain individual vegetarians, and even vegetarian races, have for long been unconsciously employing the second method of attacking the problem of the proteid optimum, Chittenden was the first to use it deliberately and experimentally on a sufficiently 24 FOOD AND DIETETICS large scale, and under rigid scientific conditions. His results showed l that in groups of professional men, athletes, and soldiers, nitrogenous equilibrium, health, and efficiency could be maintained for periods of some months on a daily intake of proteid of less than 60 grammes, or about half that contained in most freely chosen diets. Chittenden and his followers do not shrink from the logical con- clusion of these experiments. They believe that the proteid standard of 120 grammes, which has been accepted ever since Voit first set it up, is far too high, that it is wasteful economically, and, not only so, but injurious to health, by throwing upon the organs of digestion, assimilation, and excretion an unnecessary amount of work. It need hardly be said that the champions of the orthodox standard have not been backward in subjecting Chittenden's experiments, and the con- clusions founded upon them, to criticism, and, apart from technical questions as to his methods, the following summary of objections to the general adoption of a low proteid standard may be stated : 2 (a) Although such a standard may be adopted with apparent impunity for a period amounting even to several months, it does not follow that it can be safely pursued for years. The remote consequences in a lowered resistance to disease and in general diminution of tone might well be injurious. As Rubner has put it, 3 the excess of proteid in the ordinary diet is to be regarded as a margin of safety, just as one builds a bridge considerably stronger than is necessary for the maximum load it has to carry. (b) There is reason to believe that persons who are accustomed to ingest but little proteid are unable to assimilate an increased amount when necessary. In wasting diseases and in con- valescence this would prove harmful. (c) The attempt to carry on life upon a minimum of proteid may result in a loss of nitrogenous substance from the body in slight and temporary disturbances of health, which it may take weeks to replace. (d) If hard work is done on a small proteid intake, the necessary energy can only be obtained by increasing the supply of fat 1 See ' Physiological Economy in Nutrition.' New York : Frederick A. Stokes Co., 1904, and 'The Nutrition of Man.' London : Wm. Heinemann, 1907. a For an able discussion of the whole question see Sir James Crichton Browne's 'Parsimony in Nutrition' (London and New York: Funk and Wagnalls Co.), 1909; and for detailed criticism of Chittenden's methods see Benedict, Amcr. Jotmi. ofPhys., 1906, xvi. 409. s ■ Volksernahrungs-Fragen,' p. 41. AMOUNT OF PROTEID REQUIRED 25 and carbohydrates to a point which may be greater than the digestive organs can comfortably stand. («) The assertion that the prevalent proteid standard is injurious to health is based upon insufficient evidence, and is opposed to universal experience. Here, for the present, we must leave the question, although we shall return to its discussion later on (p. 173). Whether the old standard of 120 grammes or the new one of 60 grammes is better time alone can show. ' The truth is great and will prevail.' It is only by the adoption of the lower standard by a sufficiently large number of individuals in varied circumstances, and over a long period of time, that the desirability of its general adoption can be proved ; and owing to the great interest which Chittenden's work has aroused, there can be little doubt that such evidence will one day be forthcoming. Meanwhile this must be said : that whatever may prove to be good for an ordinary adult, there can be no question that in the case of children, adolescents, and pregnant women, it is far safer to adopt a high proteid standard than a low one. No risk must be run of not providing a sufficiency of material for the com- plete building up of the growing organism. We may now turn to the other division of our problem, and ask : How much Potential Energy should the Diet contain ? This question, being purely one of physics, is much more easily capable of exact solution, and fortunately the reply given to it by physiologists is fairly definite and unanimous. The data necessary for its solution may be obtained in two ways. There is first what one may call the purely physiological method. A man is shut up in a respiration-calorimeter. All the heat which he gives out from his body in a given time is measured, and the work which he does is also measured and expressed in terms of heat. The result stated in the form of Calories gives the amount of energy which has been expended by the body in a given time, and consequently the amount of potential energy which must be supplied in the form of food to main- tain equilibrium. Such a method is necessarily very laborious, and only a limited number of observations by it are yet available, most of which have been made in America; 1 but there can be no doubt that it will be much more largely employed in the future. The results yielded by this method, when translated into quantities of 1 See Bull. 109, United States Department of Agriculture (Off. of Experiment Stations), 1902. 26 FOOD AND DIETETICS ordinary food-stuffs, form the basis of standard dietaries. By far the larger number of observations have been made by what may be called the empirical method. A healthy individual living under known conditions, and on a freely-chosen diet, is selected ; the food which he eats and the excreta given off from his body are analysed, and in this way one discovers whether or not the income in diet is equal to the expenditure as represented by the waste products excreted and the state of the individual's weight. The method may { be modified by varying the diet in different directions, and seeing how each change affects the balance-sheet of the body, or groups of persons living under similar conditions may be chosen instead of individuals, and the average amount of food required calculated from the total consumed by the group. Such observations have mostly been made on the inmates of public institutions. From the data yielded by this method actual dietaries can be drawn up, some examples of which will be given immediately. A study both of standard and actual dietaries shows that a man of average weight (n stones), and doing a moderate amount of muscular work, must be supplied daily with an amount of energy in the form of food which is the equivalent of from 3,000 to 3,500 Calories. 1 We have now to ask, What proportion of this total should be supplied in the form of proteid, carbohydrate, and fat respectively ? As regards proteid, we have already seen that the amount recom- mended by most physiologists is 120 grammes daily, which would yield about 15 per cent, of the total energy required. We have only to consider the remaining question — How much Carbohydrate and Fat should the Diet contain ? As far as the demand of the cells for energy is concerned, it is probably a matter of indifference how much of the total energy required is obtained in each of these forms, provided one remembers always that it takes i\ parts of carbohydrate to supply as many Calories as 1 part of fat. To the digestive organs, however, it is by no means a matter of indifference. If all the energy not provided as proteid were to be supplied in the form of carbohydrate, it would mean that a large hulk of food must be consumed, which would be not only apt to overload the stomach and intestines by its mere weight, but would also be prone to undergo fermentation, leading to the production of flatulence and acidity. If, on the other hand, fat 1 According to Chittenden {op. cit.), this is considerably in excess of the amount actually required by a man doing only moderate muscular work. FAT AND CARBOHYDRATE REQUIRED 27 be adopted as the exclusive source, one would run the risk of over- stepping the limits of fat absorption, and nausea, and probably diarrhoea, would ensue. In this matter habit and personal peculi- arity have a great influence. There are some races, such as the Esquimaux, who take almost the whole of their energy in the form of fat ; others take it mainly in the form of carbohydrates. The Scotsman is notoriously less inclined to eat fat than the Englishman, and one constantly meets with individuals who have an insuperable repugnance to the consumption of even moderate amounts of fat. We have already seen that 150 grammes of fat can be absorbed daily without much difficulty, but in most persons anything above 100 grammes (3J ounces) in winter, and rather less in summer, would be apt to produce disorders of digestion. For this reason alone, therefore, it is well to take a mixture of carbohydrate and fat rather than either of these exclusively, and 50 grammes of fat ( = 2 J ounces of butter) to 500 of carbohydrate ( = 1 pound 2 ounces of sugar) may be regarded as a reasonable proportion. This is in the ratio of 1 part of fat to 10 of carbohydrate. Many authorities, however, recommend more of the former and less of the latter. Some direct observations on this point were made by Forster 1 on the actual dietaries of different individuals. He found that to every part of fat the following amounts of carbohydrate were consumed : Subject. Carbohydrate. Infant 14 Child of five months 1-4 Labourer's child . . . . . . 56 Well-to-do adult 34 Labourer 5° Old man 5' 1 Old woman 53 Nursing woman . . . . . . 2-4 The results show that in every case investigated the quantity of fat obtainable was considerably greater than the amount fixed in the standard. The question of expense also comes in here. Fat is a dear but compact form of energy ; carbohydrate is bulky but cheap. Those who can afford it usually try to get the advantages of a condensed food, in spite of its greater cost ; while those to whom pecuniary considerations are of importance must put up with the inconveniences of the more bulky food in exchange for its greater cheapness. Hence one finds that, as a matter of observation, the food of the rich is usually much more fatty than that of the poor. 1 Pettenkofer and Ziemssen's ' Handbuch der Hygiene,' 1882, Bd. I., p. 137. 28 FOOD AND DIETETICS Opportunity, also, is a determining factor. The Esquimaux eats much fat because he cannot grow crops ; the Hindoo consumes much carbohydrate because he has got facilities for growing rice. Here, as in so many other cases, necessity determines the choice, and custom makes it the most agreeable. Notwithstanding the above considerations, to which the practical solution of the question must usually be left, it is still of some scientific interest to ask whether there may not be some part played in the body by fat which is not so well fulfilled by carbohydrates, and vice versa. There is not much in the way of experimental evidence to help us in coming to a conclusion on this point, but there is a prevailing belief among competent observers that in the diet of children, at least, a deficiency of fat cannot be replaced by an excess of carbohydrate, and that fat seems to play some part in the formation of young tissues which cannot be undertaken by any other nutritive constituent of food. 1 The association of rickets, especially, with a deficiency of fat in the diet seems to be pretty firmly estab- lished. An attempt has been made 2 to put this belief to the test of exact experiment by feeding young pigs on milk from which almost the whole of the fat had been removed by a separator. It was found, however, that the animals so fed did not become rickety, nor did the fatty matter which is so abundantly present in the central nervous system undergo any diminution. On the other hand, the subcutaneous fat almost entirely disappeared, and was replaced by a gelatinous sort of connective tissue. The curious fact was also observed, that the deficiency of fat in the food led to an interference with the absorption of phosphorus, although no explanation of this is advanced. If a large excess of carbohydrate was supplied, it was found that the subcutaneous fat did not undergo such marked diminution. It must be admitted that the belief that fat is necessary for the formation of new tissues receives but little confirmation from this experiment. One point in which fat is not able to replace carbohydrate in its dynamic equivalent is in proteid-sparing power. In this direction i part of fat is not as efficient as i\ parts of carbohydrate. 3 If, therefore, the proportion of fat in the diet be increased, the amount 1 See, for example, Cheadle, 'Artificial Feeding and Food Disorders of Infants ' (London: Smith, Elder and Co.), p. 12. 2 Journal of Experimental Medicine, 1898, iii. 293. 8 See Von Noorden, ' Pathologie des Stoffwechsels,' p. 117. Wicke and Weiske (Zeits. f. physiol. Chemie, 1895, xxi. 42, and 1896, xxii. 137) found that 100 grammes of starch diminished proteid katabolism 19 to 21 per cent. ; a similar weight of fat diminished it by 30 to 40 per cent. ; i.e., the absolute effect of fat is greater than that of carbohydrate, but the relative effect is less. NUTRITIVE RATIO 29 of proteid consumed must also be increased. An examination of freely-chosen diets shows that this is actually done. One may sum up the standard amounts of the different nutritive constituents required daily thus : Proteid 120 grammes ( 3 ounces). Carbohydrate .. .. 500 ,, (18 „ ). Fat 50 ,, ( if ,, ). These would yield the following amount of energy in Calories : Proteid .. .. .. i20X4'i=492 Carbohydrate . . . . 500 x 4' 1 = 2050 Fat 5°X9'3=4 6 5 Total .... = 3007 Calories. Such a standard may be regarded as suitable for a man of average build and weight, and doing a moderate amount of muscular work, and if a greater intake of energy is demanded, it should be met by increasing the amount of fat consumed. In the following table I have collected similar standards fixed by other workers : * Authority. Proteid. Fat. Carbohydrate. Calories. Moleschott 105 125 118 127 119 130 125 56 35 56 52 51 40 125 500 540 500 5°9 531 55° 45" 3,022 3.030 3.055 3,092 3,140 3,160 3.520 Average 121 59 5IO 3.135 It will be observed that the chief point of divergence is in the relative proportion of carbohydrate and fat ; the amount of proteid is very similar in all. The total Calories yielded is remarkably constant, despite these divergencies. It should also be stated as regards that point that in these standards no account is taken of the inevitable loss resulting from incomplete absorption of the con- stituents. To allow for this, the total Calories yielded would require to be reduced in each case by about 200. In such standards the ratio of proteid to carbohydrates and fat taken together is of some importance. It is called the nutritive ratio. If 1 part of fat be counted as i\ parts of carbohydrate, the 1 Chittenden's standard has not been included, but it may be taken as 60 grammes of proteid, and a total fuel value of 2,800 Calories. He has not attempted to fix the proportion of fat and carbohydrate. 3 o FOOD AND DIETETICS nutritive ratio in the average of the above standards is as i to 53. In this ratio we have an index of the proportion which the building material of the diet ought to bear to its purely energy-yielding con- stituents. It need hardly be remarked that we do- not consume our food in the form of pure proteid, carbohydrate, and fat. If, therefore, the above conclusions are to be of any practical value, they must be translated into terms of ordinary articles of diet. Necessity for a Mixed Diet. In the first place it may be remarked that no one article of food contains the different nutritive constituents in proper propor- tions. Some foods are too rich in proteid ; others contain too much carbohydrate and fat. The former statement is true of all animal foods, and, amongst the vegetable foods, of such articles as dried peas, beans, and lentils. Most other vegetable foods, on the con- trary, of which bread and potatoes may be taken as types, contain an excess of carbonaceous constituents. The practical outcome of this is that a proper diet must be a mixed one, the excess of a particular element in one article being played off against its deficiency in another. People have found this out for themselves by experience ; hence the popularity of such combinations as bread and cheese, bacon and beans, or potatoes and beef, in which the surplus of carbohydrate or fat in the first article is made up for by the excess of proteid in the second. In a similar way we strike a proper balance in puddings by compounding them of articles rich in proteid on the one hand, such as eggs and milk, with articles containing a surplus of carbohydrate on the other, such as rice or bread. The use of white sauce with fish is an example of a similar adaptation. That mankind is right in so doing is borne out by the disastrous results which have followed attempts to live for any length of time on a single article of diet. Hammond 1 tried to live on a daily ration of a pound and a half of starch, along with water. He had to abandon the experiment on the tenth day, owing to the onset of debility and fever. On another occasion he attempted to live on nothing but albumin. After nine days diarrhcea and albuminuria supervened, and the experiment had to be given up. ^Transactions of the American Medical Association, 1857,' x., p. 511, For similar experiments see Flint's ' Physiology of Man,' 1867, ii., p. i?8. STANDARD DIETARIES 3i The following table represents, with some modifications, standard daily dietaries constructed by Atwater : STANDARD DIETARIES. Daily Dietaries. — Food materials furnishing approximately the 28 pound ( = 125 grammes) of proteid and 3,500 Calories of energy of the standard for daily dietary of a man at moderate muscular work. Cost. Nutritive Constituents. Fuel Total value. Organic Matter. Proteid. Fats. Carbo- hydrates.. I. Ounces. s. d. Pounds. Pounds. Pounds. Pounds. Beef, round steak . . "3 6 •26 ■14 '12 — Butter 3 3 *i6 •16 — 680 Potatoes 6 o.J *'7 ■02 320 Bread 22 O 2^ •89 *12 ■02 '75 1,760 44 I O 1 '48 •28 '30 •90 3.4SS II. Pork, salt 4 O l£ '21 •21 880 Butter 2 O 2 ■11 450 1,615 16 O 2& •84 '=>3 ■02 ■59 8 O X •33 •04 *ox •28 640 30 O 7 1 '49 •27 '35 ■87 3.585 III. Beef, neck . . . . 10 O 2j ■19 *IO •09 Butter 1 O I ■05 •05 Milk, t pint .. 16 O 2 ■13 ■04 •04 Potatoes 16 O I ■17 •02 •15 320 Oatmeal . . 4 O I ■=3 ■04 ■02 16 O 2 ■67 •09 '02 ■S« 1,280 3 ah •19 — "'9 345 66 O 10 I "63 •29 '22 I '12 3,505 IV. Beef, upper shoulder to 3i '22 •09 ■13 — 800 6 3 ■19 ■06 ■13 650 Two eggs . . . . 3 2 'OS ■03 '02 Butter 2 2 'IX 450 Milk, 1 pint .. 16 2 ■13 •04 •04 'OS Potatoes . . 12 o| *I2 *OI *II 240 825 9 of ■44 •OS •01 •38 X c»i ■06 — — •06 "5 59 1 =1 I-32 ■28 '44 ■60 3.540 V. Sausage . . 4 xft •»4 ■°3 "II 510 Cod-fish 14 3i •07 •07 — 140 Butter 2 2 *II 'II — 45o Milk, 1 pint .. 16 2 ''3 •04 •04 'OS 325 5 0% •26 '°7 '01 •l8 505 2 04 "ii ■01 — *IO 205 Potatoes . . 16 O X ■*4 *OI — •23 420 9 I ■33 ■04 *OI •28 640 3 o£ ■19 — — ■19 345 7 1 1 °2 1-58 •27 ■28 I -03 3,540 VI. Beef 8 3 •18 •08 •10 S«o Mackerel, salt 4 ik ■08 ■04 •04 230 J wo eggs 3 2 '°5 •03 ■02 '35 Butter =i %\ '13 — ■13 565 Cheese I oj ■04 •02 •02 130 Milk, 1 pint .. 16 O 2 ■■3 •04 ■04 'OS 325 Potatoes 8 o£ ■09 •01 ■08 160 2 o\ '11 '01 — "IO 205 9 I •38 ■05 •01 •32 720 1* oj ■69 — — ■09 175 55 1 ij x-88 28 ■36 •64 3.205 * The prices given in this table are those which rule in America. They are not always the same s those in this country, but the value of the fibres is not really affected thereby. 32 FOOD AND DIETETICS It is worth while noticing, incidentally, the relative cost of these diets. Compare, for example, in this respect, No. II. with No. IV. Both of these contain practically the same amount of nutriment, but the latter costs exactly twice as much as the former. This is a fresh proof of the fact which has already been insisted upon, that the cost of a diet is no indication of its nutritive value. The total weight of dry food which is consumed daily in such a standard diet as any of the above is about 23 ounces (or almost 1 ounce per hour). This represents 45 ounces (nearly 3 pounds) of ordinary food. Actual Dietaries. The standard dietaries given above are constructed, as we have seen, from theoretical data. It is interesting to compare with them the composition of the ordinary diets actually consumed by individuals of different countries and different social rank. In the following table (also modified from Atwater) 1 a large number of such dietaries have been collected : ACTUAL DIETARIES. Classes. 1. Sewing- girl, London, wages 3s. gd. per week 2. Factory girl, Leipsic, Germany, wages 5s. per week 3. Weaver, England, time of scarcity 4. Labourers, Lombardy, Italy ; diet mostly vegetable 5. Trappist monk in cloister ; very little exercise, . vegetable diet 4 6. Students, Japan 7. University professor, Munich, Germany ; very little exercise 8. Lawyer, Munich 9. Physician, Munich 10. Painter, Leipsic, Germany xi. Cabinet-maker, Leipsic, Germany 12. * Fully-fed ' tailors, England 13. 'Well-paid' mechanic, Munich, Germany .. 14. Carpenter, Munich, Germany 15. ' Hard-worked ' weaver, England 16. Blacksmith, England 17. Miners at very severe work, Germany 18. Brick - makers (Italians at contract work), Munich 19. Brewery labourer, Munich ; very severe work, exceptional diet . . _ so. German soldiers, peace footing 21. German soldiers, war footing 22. German soldiers, Franco -German War ; extra- ordinary ration 23. Russian workmen 24. Swedish workmen (moderate labour) . . 25. Swedish workmen (bard labour) Nutritive Constituents. Proteid. Grms, 5a 60 68 97 100 80 131 87 77 131 151 131 151 176 133 167 223 114 134 157 132 134 189 ^ - hydrat°es. *•"»!■ Grms, 33 53 125 95 69 57 39 54 68 43 71 113 "3 39 58 285 80 79 no Grms. 316 301 398 362 469 438 240 222 327 366 466 525 479 494 622 667 634 675 909 480 489 33' 583 523 714 4c6 486 484 548 551 440 4*7 553 522 600 695 684 693 816 914 880 959 1.245 633 681 Potential Energy. Calories, 1,82a 1,940 2,138 2,304 2.343 2,324 2,401 2,762 2,500 2,757 3.053 3,085 3.194 3.509 4,117 4. "95 4.641 5,692 2,798 3.093 4>652 3.675 3.436 4,726 1 Report of United States Commissioner of Fish and Fisheries, 1888. ACTUAL DIETARIES ACTUAL DIETARIES— continued. 33 Classes. 326. 33^- 26. French Canadians, working people, in Canada 27. French Canadians, factory operatives, me- chanics, etc., in Massachusetts 28. Other factory operatives, mechanics, etc., Massachusetts 29. Glass-blowers, East Cambridge, Mass. 30. Factory operatives, dressmakers, clerks, etc., boarding-house 31a. ) Well-to-do private family, f food purchased 31&, ) Connecticut (food eaten _. f College students from"\ , e , , , 3 s ?" I Northern and East-] 1 food purchased em States : boarding- \ ] \°°° eate " , club, 2 dietaries of the | i f ™* Phased same club J ' food eaten 34. College football team, food eaten 35. Machinist, Boston, Mass. 36. Brick-makers, Middletown, Conn 37. Teamsters, marble-workers, etc., with hard work ; Boston, Mass. 38. Brick-makers, Cambridge, Mass 39. U.S. Army ration 40. U.S. Navy ration 41. Average of 53 American studies for different classes 42. Average diet of labourer's family in Edin- burgh . . _ . . _ Chinese dentist's family Japanese professional man Professional men in America (average of 14 studies) 46. Malays (professional men) .. 47. Europeans in Java (professional men) 48. University boat crews (average of 7 studies) 49. Average of 4 women students' clubs in America 50. Average of 16 men students' clubs in - America 51. Average of 21 dietary studies amongst the labouring classes in Dublin 52. Average dietary of 5 halls of residence for students in Edinburgh 53- Dietary of a students' club in Finland 1 Nutritive Constituents. 43- 44. 45- Proteid. Grms. 109 118 127 95 114 729 123 161 138 "5 104 181 182 222 254 180 Z20 143 107*7 "5 63 104 73 100 155 143 157 Fats. Grms. 109 186 132 150 183 177 204 184 "63 136 254 263 363 365 161 184 "3 3 •25 3° 84 177 139 147 138 191 Carbo- hydrates, Grms. 527 549 53i 481 522 467 466 680 622 460 421 557 617 758 826 1,150 454 520 436 479'4 289 481 423 472 264 440 465 453'fi 5" 380 Total. Grms. 745 871 844 708 786 779 771 1,045 944 738 661 1,030 1,053 1,243 1,443 1,695 735 847 677 675"5 Potential Energy. Calories. 3,622 4,°3* 4,428 3,59o 4,002 4,146 4,082 5,345 4,827 3,874 3,417 5,742 5,638 6,464 7,804 8,848 3,851 4,998 3.5oo 3,228 2,705 3,3*5 2,512 2,470 4,085 3,405 3,705 3,"7 3,979 3,984 On examining the table, it will be observed that, on the whole, the results conform very closely to the ideal standard already laid down. Here and there, however, one meets with divergences. Thus, the diet (No. 1) of the sewing-girl in London (which was investigated by Playfair) must be regarded as insufficient for the needs of health, while that of the well-to-do family in Connecticut (No. 31) is need- lessly liberal. Taking the results as a whole, however, one is astonished at the closeness with which the actual corresponds to the ideal. 1 Sundstrbm, Skand. Archiv ]. Physiol., 1907, xix. 78. 3+ FOOD AND DIETETICS Application of these Standards. It must be clearly realized that such standard dietaries as those we have been considering have only a limited range of usefulness. They cannot be rigidly applied in any particular case, for they have only been drawn up to meet the needs of typical individuals living under known conditions, and doing a moderate amount of muscular work. They are of great value, hov/ever, in helping us to draw up rations for persons who have no free choice in their diet, and who are living under fairly uniform conditions (e.g., soldiers and the inmates of prisons, workhouses, etc.), and' as furnishing us with a standard by which to gauge the probable sufficiency or otherwise of the dietary which choice or necessity has imposed upon any section of the community. A good example of the application of such a standard in the former case is supplied by Dr. J. C. Dunlop's investigations into prison diets in Scotland. 1 Illustrations of its use in estimating the value of the diet in sections of the community have been furnished in this country by the investigations of Noel Paton and others into the diet of the labouring classes in Edinburgh, 2 those of Rowntree into that of the poorer sections of the community in York, 3 of C. D. La Touche and T. T. Stafford in the case of working-class families in Dublin, and of Miss I. D. Cameron into the dietary in five students' halls of residence in Edinburgh. 4 The results of these investigations will be referred to in the next chapter. 1 Report to the Prison Commissioners for Scotland. London : P. S. King and Son, 1899. 2 ' A Study of the Diet of the Labouring Classes in Edinburgh.' Edinburgh : Otto Schulze and Co. 3 ' Poverty : A Study of Town Life.' London : Macmillan and Co. New edition, 1903. * Proceedings of the Royal Society of Edinburgh, 1905-6, xxvi., 327. [ 35.] CHAPTER III ON THE INFLUENCE OF VARIOUS CONDITIONS UPON THE AMOUNT OF FOOD REQUIRED i. Work and Rest. Of all the factors which affect the amount of food required, work and rest are by far the most potent. So much is this the case that all other influences are negligible in comparison. We shall consider the influence of muscular work first. We may accept Frankland's estimate that a hard day's work for a man of 10 stones would con- sist in raising his own weight to a height of 10,000 feet, which would be the same as ascending a ladder 2^ miles high. This means the expenditure of 1,400,000 foot-pounds of energy, or about 200,000 kilo- grammetres. 1 Now, the equivalent of 1 Calorie in mechanical energy is 3,077 foot-pounds, and if a man is supplied with 3,000 Calories daily, this yields him more than 9,000,000 available foot-pounds of energy. In other words, under ordinary circumstances a man transforms less than one-sixth of the available energy of his food into work, the rest being lost in the form of heat. This loss is inevitable, but it compares favourably with the similar loss in a steam-engine, in which the work done represents at most one-eighth ■ of the potential energy of the fuel consumed. Seeing that it is not possible to convert any of this waste heat into work, more food must be taken the greater the amount of labour required to be done ; and the following may be accepted as standards of the number of Calories which must be supplied for work of different degrees of severity (Rubner) : 1 The estimate of a ' fair day's work for a labourer' given by different writers varies greatly. It is placed by some as low as 150,000 kilogrammetres, by others as high as 340,000. It is certain, however, that the last amount could not be performed continuously by the average man. 3—2 36 FOOD AND DIETETICS 1. Rest (e.g., clerk at a desk) 2. Professional work {e.g., a doctor) . . 3. Moderate muscular work {e.g., a house-painter) 4. Severe muscular work {e.g. , a shoemaker) 5. Hard labour (e.g. , a blacksmith or navvy) 2,500 Calories. 2,631 3. "i 3.659 5.213 A reference to the table on p. 31 will show that even larger quantities than the last of these are sometimes actually consumed. Brickmakers, for example, whose occupation is one of the most laborious known, were found to take in food to the value of more than 8,000 Calories daily. On the other hand, a German doctor consumed less than 3,000 Calories, although medicine is by no means a sedentary occupation, while the consumption of a Trappist monk, living in the retirement of the cloister, amounted to hardly more than 2,000 Calories per day. Atwater's American standards are as follows : Calories. Man without muscular work . . . . . . . . 2,700 Man with light muscular work . . . . . . . . 3,000 Man with moderate muscular work . . . . . . 3,500 Man with severe muscular work . . . . . . . . 4,500 The standards determined by Lyon Playfair as long ago as 1865 work out in Calories thus : J Calories. Subsistence diet .. .. .. 2,102 Soldier (peace), light work .. .. .. .. .. 3,029 Soldier (war), moderate work .. .. .. .. 3,146 Royal Engineers, moderate work . . . . . . . . 3,818 Labourers, moderate work .. .. .. .. .. 3,611 Average for moderate work .. .. .. .. 3,525 Admitting that with an increase of work there must be a corre- sponding increase in the total amount of food consumed, the further question arises, In what form is the extra energy to be supplied ? Should it be met by an increase of proteid, of carbohydrate, or of fat, or should all be increased alike ? In attempting to reply to this question, we enter the arena of much physiological controversy, for, stated in another way, the problem to be solved is this : from what source do muscles derive the energy which enables them to do work ? In the earlier part of the last century most physiologists believed with Liebig that nitrogenous matter — in short, proteid — was the muscle food par excellence. It was supposed that if much work had to be done, much proteid must be supplied. Soon there arose another school, who contended, and backed their contention 1 See ' A Study of the Diet of the Labouring Classes in Edinburgh,' by Noel Paton, J. C. Dunlop, and Elsie M. Inglis, p. 5. Edinburgh: Otto Schulze, 1901. DIET STANDARDS FOR HARD WORK 37 by incontrovertible experimental evidence, that, when hard muscular work is done, it is the carbonaceous, and not the nitrogenous, constituents of the body which suffer increased waste. Of the carbon containing constituents of the food, the carbohydrates soon came to be regarded as the most valuable sources of muscle energy, a view in favour of which evidence is still accumulating (see p. 282). But, as often happens with the progress of knowledge, our views on this subject have tended to swing back a little, and now physiological opinion seems to have crystallized in a middle position, in which it may be said that a muscle is able to utilize any of the nutritive constituents of food for its work, but that, as long as there is a sufficiency of carbon-compounds present, these are pre- ferred to the nitrogenous. To those who wish to follow the steps which have led to this position of equilibrium, the study of a paper by Dr. Noel Paton in the Edinburgh Medical Journal for 1895, p. 1081, may be commended. 1 Dr. Paton compares the advance of our knowledge in this matter to the tacking of a ship against the wind, and expresses the belief that we have now reached the haven in the middle position above referred to, namely, that muscular work makes no special demand on one nutritive constituent of the food more than another. Direct observation of the diets actually selected by men engaged in severe toil confirms this conclusion. Diets Nos. 16, 17, 33 and 34, in the table (pp. 32,33) may be taken as examples. It will be observed that in these all the nutritive constituents are increased, but that some have elected to consume the excess of carbon in the form of fat, others chiefly as carbohydrate. Both meet the requirements equally well, but carbohydrate has the advantage of being a cheaper source of supply. On the other hand, fat is less bulky, and those who can afford it do well to take in a large share of the increased energy they require in that form. An increase of proteid in the diet of toil is necessary, not so much to provide additional energy as to make good the increased wear and tear of muscle substance which the performance of hard work necessarily involves, as well as, in some cases at least, to enable the muscle to add to its bulk. From an examination of such diets, the following standards have 1 For some recent experimental evidence leading to the same conclusion see Frentzel ( ' Ergographic Experiments upon the Restorative Effects of Various Nutritive Substances in Muscular Fatigue '), Archiv.fiir Anat. unit Physiol,, Sup. Bd., 1899, p. 141. 38 FOOD AND DIETETICS been constructed, which may serve as guides to the amount of each nutritive constituent required during the performance of hard labour : Authority. Proteid. Fat. Carbohydrate. Calories. Voit .. 145 100 45° 3.370 Rubner 165 70 565 3.644 Playfair 185 7i 568 3.750 Atwater 150 150 500 4,060 The amount of proteid allowed is in each case considerably above the average standard for moderate work (120 grammes). The sum of carbohydrate and fat is also raised, but in some cases the main increase has fallen upon the former, in others upon the latter. The subject under discussion has important bearings upon the diet of training. Training may be described as a process by which the body is fitted to perform severe muscular feats. 1 The chief means by which one seeks to accomplish this object are the reduction of weight by the removal of superfluous water and fat, and the improvement of the tone of the muscles and heart, which produces endurance and long * wind.' The first of these objects is attained by reducing the amount of fat in the diet, and by restricting the amount of fluid to that which is required to satisfy actual thirst. That the reduction of fluid in the body is physiologically justifiable is evident from the fact that a watery condition of the muscles and blood does not conduce to an energetic condition of body (see also p. 180). On the other hand, the opposite extreme should be avoided, for a too viscid condition of the blood is equally unfavourable. No dietetic means have been consciously used to accomplish the second object — the improvement of the tone of the muscles and heart. Experience, however, seems to show that the results of these — i.e., a gain in power of endurance and wind — are attained by increasing the amount of proteid consumed, and in practice this takes the form of eating large quantities of meat. It may be asked if this increased consumption of proteid can be defended on scientific grounds. To some extent, yes. Proteid is the nutritive ingredient least likely to be converted into fat, and is also, on the whole, the most easily digested, and any disturbance of digestion seems to militate greatly against the accomplishment of the objects of training. Moreover, the hard exercise which is practised during training 1 See also on this subject Clement Duke's ' School Diet,' chapter xi., 'The Diet in Training for School Games. ' DIET STANDARDS FOR HARD WORK 39 involves a great deal of wear and tear in the muscles, and sometimes also an increase in their bulk, and both of these results must be provided for by an increased consumption of pro- teid. Further, also, in sudden and short muscular feats, such as those for which training is a preparation, what is required is a large output of energy for a short time. Proteid, being a ' quick fuel,' is probably better adapted to secure this end than either carbohydrate or fat. 1 In recent years there has perhaps been a tendency to lay less stress on the use of meat, to recognise that in training, as in other conditions, the same diet does not suit all persons equally well, and to recommend, rather, the use of ordinary foods, taken in increased quantity, and with the avoidance of anything likely to produce indigestion, such as pastry and sweets. This is probably a move in the right direction ; but one would like, on scientific grounds, to see sugar more largely tried. The tendency would still seem to be to eat too much and at too long intervals. ' He that striveth for the mastery,' says the Apostle, ' is temperate in all things.' And this applies to diet as well as to everything else. The chief scientific studies of the dietaries of persons engaged in athletic exercises have been made in America. 2 One of these concerns the diet of Sandow, ' the strong man,' and is on that account of some special interest. We read that : ' Mr. Sandow does not follow any prescribed diet, but eats whatever he desires, always being careful to eat less than he craves rather than more. He eats very slowly. . . . Sometimes he takes a cup of weak tea and a little bread in the morning, but usually his first meal is eaten about noon. He eats again about six o'clock, and again about midnight, after his exhibition of feats of strength is over. He smokes a good deal, and drinks beer and other alcoholic beverages.' ' The total amount of food consumed,' says the writer, ' is rather more than the average, though in his own opinion Mr. Sandow is not a large eater. This is in accord with the general conclusion reached in many investigations made with labouring men, that severe muscular exercise requires an abundant diet.' 1 It is also beginning to be believed by some physiologists that work which causes a high degree of nervous and mental strain demands for its performance a larger supply of proteid than the same amount of labour carried out in a more leisurely manner and under less pressure. 2 Langworthy and Beal, Storr's Agricultural Experiment Station, Ninth Annual Report, part ii., 1896. 40 FOOD AND DIETETICS The following table represents, approximately, Sandow's diet for one day : Food Consumed. % (Quantities in Ounces.) Nutrients. Potential Energy. |. Date. s Ext yun. 10. Dinner -\ Supper ■ yan. ii. Break- fast^ 2 oysters, io soup, i celery, 3 fish, 1 potatoes, 2 oyster plant, 1 green peas, 1 tomatoes, 2 bread, 2 roast beef, 24 chicken, 4 ice cream, 3 orange sherbet, \ cakes, 1 butter, 11 wine (Burgundy) .. 8 roast beef, 7J rye bread, 34 Cam- embert cheese, 2 water biscuit, 3J cakes, 4-4 lb. beer* 9 vegetable soup, 2 potatoes, 3 veal (breaded chop), £ green peas, 2 roast beef, 4J bread pudding, Total in pounds . . Total in grammes a. ■17 •26 •11 lb. •14 ■14 •05 lb. 34 •61 ■16 Calories. 1: 5-4 244 3 '3 151 I'll 502 4,462 3*4 The average composition of the diet consumed by some University boat crews in America was as follows : 3 085 Calories. l = 4,o8 of college football teams yielded the 155 grammes 177 440 Proteid Fat Carbohydrates Two studies of the diet following results : 4 No. 1. Proteid .. 181 grms.l _ 5 ^ (Calories. An investigation of the diets of two Scandinavian professional athletes resulted as follows : 5 Fat .. ..292 Carbohydrates 557 No. 2. Proteid . . 270 grms Fat .. .. 416 Carbohydrates 710 ms.^ ;: j =7,885 Calories. No. 1. Proteid . . 217 grms.") = , 070 ?' ••. " 2 59 >. \ Calories. Carbohydrates 431 „ ) Proteid Fat .. .. 204 Carbohydrates 392 No. 2. • I 82grms.| =4234 " [Calories. 5) J The most striking points about the above dietaries of athletes are (1) the large amount of total energy which they contain, and (2) their 1 Sandow sat a long time with friends after supper, and consumed a large part of the beer during this time. 2 This was the regular lunch served at the hotel. 3 'Dietary Studies of University Boat Crews,' Bull. No. 75, United States Department of Agriculture, Office of Experiment Stations, 1900, p.' 66. * Ibid. ' Lavonius, Shand. Archiv. f. Physiol., 1905, Bd. xvii., 196. DIET STANDARDS FOR HARD WORK 41 richness in proteid, the former being about 15 per cent., and the latter 25 per cent., above the standard for moderate muscular work. It seems reasonable to suppose that these peculiarities are a response to the physiological demands- which athletic contests make upon the body, and that the diet of training should be one yielding a large amount of energy and containing a relatively high proportion of proteid. Mental work influences the amount and nature of the food required in a very different way from muscular labour. The first thing which it is important to realize clearly is that brain work does not appreciably increase bodily waste at all. On this point all exact experiments agree. One of the most careful of these is recorded by Atwater. 1 A man was confined in a respiration calori- meter for a number of days, and on certain of them he engaged in the severe mental work of reading a German treatise on physics. The subject of the experiment, it may be added, was an intelligent person, who fully understood the nature of the experiment, and did not shirk mental application. It was found that on the working days bodily waste was no greater than during rest. The next point to get hold of is that there is no special brain food. Buchner gave utterance to the dictum, ' Without phosphorus there is no thought.' This is only true in the sense that the brain contains phosphorus, and without the brain, thought, as we know it, is unthinkable. But it has never been shown that an increased supply of phosphorus in the food is specially favourable to mental effort, nor, indeed, has that been proved for any other food. 2 It requires, of course, no special demonstration that an ill-nourished brain is not one from which good work can be expected : for the brain, like every other organ, demands for its work an abundant supply of healthy blood, and there is, perhaps, no part of the body which is more sensitive to any impoverishment of that fluid. On the other hand, any oversupply of food must be equally unfavourable to mental work. A large amount of food implies a large amount of work on the part of 1 United States Department of Agriculture, Bull. 44, 1897. For later experi- ments, which also tended to show that mental effort has no positive influence on metabolism, see United States Department of Agriculture, Office of Experiment Stations, Bull. 208, 1909. 2 Mairet and Florence (abstract in Brit. Med. Journ., 1907, ii. 539) have shown by experiment that during intellectual labour the amounts of nitrogen and phosphoric acid absorbed from the alimentary canal are'diminished, as compared with the period of repose, either following or preceding the spell of mental work, and that appreciably more phosphorus is eliminated during mental work than is absorbed in the same time. These results, however, might be explained by an adverse influence exerted by hard mental labour on the processes of digestion and absorption. 42 FOOD AND DIETETICS the digestive organs, and that, in its turn, implies a large expenditure of nervous energy and blood. But if more blood is required in the abdomen, there must be less left for the brain, and the activity of the latter declines, as is evidenced by the feeling of lethargy which is familiar to everyone after a large meal. It comes, then, to this, that the digestibility of a food is of far greater concern to a brain worker than its chemical composition. Small and rather frequent meals of easily-digested food is the ideal to aim at. The necessity for this is the more apparent when one remembers that brain work is usually also sedentary work. Compared with the diet of muscular labour, therefore, the diet for mental work should be small. The reduction should probably affect carbohydrates and fats more than proteid, for it is the two former, as we have seen, which tend to be specially made use of as muscle foods. The proteid consumed should be derived to a large extent from animal foods, for these are its most compact and digestible source; Hence it is that it is far easier for a man who is performing bodily labour to be a vegetarian, than for one who is engaged in mental work. Whether an abundant supply of proteid has, per se, an actually stimulating influence on the brain must be left undecided, though such a view is not without its supporters. 1 Best, as might be expected, influences the amount of food required in a precisely opposite direction to muscular work. Much less food is required in the former condition than in the latter. The reduction, however, should not affect all the nutritive constituents equally. Even when the body is in complete repose there is still wear and tear of its substance going on. Such waste, indeed, is inevitable, for it is an invariable accompaniment of even passive life, and one finds that during rest the excretion of carbonic acid is much more profoundly influenced than that of nitrogen. The practical result is that in the diet of repose the carbohydrates and fats should be relatively more restricted than the proteids. The energy value of such a diet may even fall to 2,000 Calories or less, and yet prove sufficient for the bodily needs. This is a fact of great value in therapeutics. It explains why it is that one has so much less difficulty in fattening a patient when at rest in bed than when up and about ; for the former condition the demand both for heat and energy is enormously lessened. Sleep intensifies the benefits of rest by insuring more absolute relaxation of the muscles, and also seems in itself to lessen somewhat the waste of fat. A German writer (Lobisch) goes so far as to assert that an extra hour's sleep at night is equivalent to a saving of 2$ pounds of fat in a year. 1 See Roberts, ' Digestion and Diet, ' p. 109. INFLUENCE OF WEIGHT AND BUILD 43 2. Influence of Weight and Build. The heavier the body — i.e., the greater the number of cells which it contains — the greater is the amount of food required for its main- tenance. This is true as a general statement, but in practice the kind of cell which is increased must also be considered. The nutri- tive requirements of a pound of bone, a pound of fat, and a pound of muscle are very different. Fat and bone are, so to speak, dead tissues. Their vital activity is but slight, their daily wear and tear small. Muscle, on the other hand, is a highly active tissue con- stantly breaking down, and requiring not merely much protied to repair its waste, but making frequent demands on the carbonaceous foods to provide it with a supply of energy. 1 Thus it is that a man whose weight is mainly due to muscle will require relatively more, and especially more nitrogenous, food than one who owes his weight to the size of his bones or to a substantial covering of fat. Taking the average man, however, the following estimate of the number of Calories required for every kilo of body-weight in different circum- stances will be found to hold good : Calories per Kilo. (2 pounds). In bed . . . . . . . . . . 30 to 34 Up, but doing no work . . . . . . 34 to 40 At moderate muscular work . . . . . . 40 to 45 At hard muscular work . . . . . . 45 to 60 On the other hand, and for the reason given above, 26 to 36 Calories per kilo will probably suffice for a man who is very stout. Rubner 2 gives the following estimates of the amount of energy and 1 Dr. Smith (Lancet, May 21, 1864) gives the amount of fat consumed under different conditions as follows : One hour of lying asleep consumes .. .. .. 031 ounce. lying awake ,, . . . . . . 046 ,, standing ,, .. .. .. 055 „ walking at two miles per hour consumes 1 ■ 1 ounoes. „ three „ „ „ 16 „ work on a treadmill consumes 275 „ Ranke compared the output of two men of equal weight, one fat, the other muscular, and both fasting, with the following results : Muscular Man. Fat Man. Proteid .... 78 50 Fat 215 204 2 Leyden's ' Handbuch der Ernahrungstherapie und Diatetik,' 2nded., vol. i., p. 153, 1903- 44 FOOD AND DIETETICS proteid required by persons of different weight in the same circum- stances : Light Work. Moderate Work Wet St. ght. lb. Calories. Grammes Proteid. Weight, st. lb. Calories. Grammes Proteid. ii 6 2,864 134 11 6 • ■ 3.372 •• 128 10 o .. 2,631 .. 123 10 • • 3,094 • • 118 9 8 .. 2,368 .. in 9 8 •■ 3,792 .. 106 7 2 2,102 go 7 z .. 2,472 .. 96 5 10 1,810 ... 84 5 10 2,129 81 The build or shape of the body is of even greater importance in this connection than its actual weight. Further, we may say that the question of build and shape, as far as the amount of food required is concerned, resolves itself into a question of surface. The larger the surface of the body relative to its bulk, the greater is the amount of heat lost by radiation, and the greater the amount of food required to maintain its temperature. A reference to the accompanying diagram (Fig. 2) will make this clear. Let us suppose that we have two bodies, the first being 9 feet high, 3 feet broad, and 1 foot thick, and the second measuring 3 feet in every dimension. Both will have a cubic content of 27 feet, but the first will have a surface of 78 square feet, the second of only 54 square feet ; in other words, the surface exposed is almost one -third greater in the one case than in the other, and the amount of heat lost will also be pro- portionately greater. The first of these figures would represent the condition of a tall, thin man, the second that of a short, stout man ; and as the former must lose about one-third more heat than the latter, he will obviously require about one- third more fuel in the form of food if the temperature of the two is to remain equal. This explains the apparent paradox, which is otherwise apt to prove rather puzzling, that a thin man often eats considerably more food than a fat man, yet the former remains lean and the latter becomes more and more stout. The former really needs more food simply because he is thin ; while the fatter a man becomes, the less food does he require, for with every increase in bulk there is a corresponding diminution in the relative amount of surface exposed. When one estimates the amount of a Fooi ^ Fig. 2. — To Illustrate the Influence of Shape on extent of Surface. INFLUENCE OF BUILD AND SHAPE 45 Calories required from the point of view of surface rather than of mass (body-weight), it is remarkable how uniform the requirement is for all persons living under the same external conditions. The extent of body-surface in an average man is about 21 J square feet, and for every iof square feet about 1,500 Calories must be supplied daily. 3. Influence of Age and Sex. It seems to be a general principle in biology, that the younger the cell the greater is its power of oxidizing and breaking down food, and that the older it is the less of this power does it possess ; in other words, what the cells of the body gain by multiplication they lose in individual activity. In accordance with this principle, the assimilative powers of a child are greater than those of an adult, and those of the latter greater than those of an old man. The child, there- fore, relatively to its weight, will require the greater amount of food. Two other considerations emphasize this necessity. Like all small animals, a child has a large surface in proportion to its bulk, and that means, as we have just seen, a relatively great heat loss. Further, a child is a growing animal ; it has not merely to keep its tissues in repair, but has to go on adding to them, and that necessi- tates a relatively abundant supply of building material. 1 The practical results of these considerations will be more fully dealt with in another chapter (Chapter XXIV.), but they have led to the following calculations regarding the total amount of food required at different ages as compared with the needs of a fully- grown man. 2 Relative Values for Food Requirements of Persons of Different Age as compared with a Man in Full Vigour at and Occupation, Moderate Work. Man, period of full vigour : At moderate work . . . . 100 At hard work . . . . . . 120 Sedentary occupation . . 80 Woman, period of full vigour : At moderate work . . . . 80 At hard work . . . . . . loo- Sedentary occupation . . 70 Man or woman : Old age go Extreme old age . . . . 70-80 Boy, 15 to 16 years old .. 13 to 14 ,, 12 years old .. ,, 10 to 11 years old Girl, 15 to 16 „ 13 to 14 ,, 10 to 12 Child, 6 to 9 „ 2 to 5 under 2 90 80 70 60 80 70 60 5° 40 3° 1 It must be remembered that during the period of active growth only a small fraction of the increased amount of food taken in is actually stored up in the body, the rest being broken down, and increasing thereby the general metabolism. For a full discussion of this point see Rubner's 'Beitrage zur Ernabrung im Knabenalter ' (Berlin : Hirschwald, 1902). s Langworthy, ' Year-book of Department of Agriculture' (U.S.A.), 1907, 46 FOOD AND DIETETICS The ' nutritive ratio ' (i.e., the proportion of building material to energy-yielding constituents) in the diet of an adult should be, we have seen (p. 29), as 1 : 5*3, or thereabouts. In the diet of a child the ratio should be approximately as 1 : 4*3. The dietetic requirements of old age are just the reverse of those of childhood. The assimilative power of the cells is on the wane 1 and the bodily activities are restricted, hence less food is required. The danger of overfeeding the old is almost as great as that of underfeeding the young ; an excess of nourishment chokes instead of feeding the flickering flame of life. Leanness and longevity, it has been remarked, go together, and a man will only roll all the faster down the hill of life if his figure be rotund. ' Discerne,' says Bacon, ' of the coming on of yeares, and thinke not to doe the same things still, for Age will not be defied,' and one cannot with impunity continue to ' do the same things ' in matters of diet any more than in anything else. Forster made some exact investigations into the diet of healthy old persons, and found that it contained the following amounts of nutritive constituents : Proteid. Fat. Carbohydrates. Calories. Men .. .. 92 45 332 2,149 Women.. ..80 49 266 1.875 The results fully bear out the above contentions. 2 In the following diagram (Fig. 3) the amount of each nutritive constituent required at different periods of life is represented. While the figures must not be regarded as in any sense absolute, they serve to represent in a graphic way the relative requirements of different ages. Luigi Cornaro is one of the most eloquent advocates of temperance in old age. ' It cannot be urged too often,' he writes, 3 ' that when the Natural Heat begins to decay 'tis necessary for the preservation of health to abate the quantity of what one eats and drinks every Day ; Nature requiring but very little for the Support of the Life of Man, especially that of an Old Man.' He tells us that he ate only 12 ounces of solid food daily, consisting chiefly of bread, wine, broths and eggs, veal, mutton, partridges, chicken, and pigeons, and some kinds of fish, such as pike, for ' all of these aliments,' ,he adds, ' are proper for old men.' His system was certainly justified by its results, for he is said to have lived to be a hundred years old. 1 Von Limbeck, ' Zur Lehre vom Stoffwechsel im Greisenalter, Zeits. fur Klin. Med., 1894, xxvi. 437. See also Sir Henry Thompson's ' Diet in Relation to Age and Activity ' for a practical discussion on the subject. 2 For further studies of the diet in old age see United States Department of Agriculture, Office of Experiment Stations, Bull. 223, 1910. s ' Sure and Certain Methods of Attaining a Long and Healthful Life,' trans- Jated from the fourth edition ; London, 1727, p. gi. Q) -f U> CD > 00. _ ID o* *1 M p o LO to * 3 n H |o CO H W a w M 3 51 i. O H :/) A *> O *. 11 •fl M 3 M Oi Z u H > t) Oi (A o> o o o> -t* 0> CD o Grammes in 24hours. CM 01 * * *e — 10 » * Co ro f» o o o o 0> o =5^- H- t AA \ u X t vf \ u N 1 I 4 / 4 / _.t if tv i h f la. 'r> iro > CK ID — — — iu ro tjt 04 m pa o o .& © iv> o o *■ **> oooooooooo •sjnoq t>3 ui sauiluEJQ A A U> U) Oi M D> O ■c 03 O O O o o 48 FOOD AND DIETETICS Women require less food than men, for their bodies are not only, as a rule, of less weight, but are relatively richer in fat and poorer in muscle than those of the latter. Further, there is a considerable amount of evidence for the belief that the cells of the body are less able to carry out oxidation changes in the female than in the male ; or, in physiological language, that the tendency of metabolism is in the direction of a preponderance of anabolism in the one case, and of katabolism in the other. Upon this supposition a whole theory of sex differences has been based. 1 Whether this be so or not, there can be no doubt that the diet of the female should be less in amount than that of the male ; and it has been estimated that, if a man consumes 10 parts of food, a woman under similar conditions should require only 8 parts. 2 Expressed in terms of nutritive constituents and Calories, the diet of an average woman doing a moderate amount of muscular work should be as follows : Proteid. Fat. Carbohydrates. Calories. go 40 400 2,381 The proportions in a condition of rest would be : Proteid 85 Fat 40 Carbohydrates 320 yielding about 2,000 Calories of energy. When one considers the relative requirements of the two sexes, it is not surprising that some of the most aggravated cases of obesity should be met with in women of luxurious life. 4. Influence of Climate and Season. The influence of climate, and especially of a warm climate, on the amount of food required is commonly exaggerated. It seems natural to suppose that, if the surrounding temperature is high, the amount of heat required to be produced in the body will be less. But this is to lose sight of the fact that the temperature of the body is chiefly regulated by physical, and not by chemical, means. To put it more plainly, we adjust the temperature of our bodies to that of the surrounding medium, not so much by the expensive method of increasing or diminishing the amount of heat we produce, as by the simpler expedient of regulating the amount of heat lost. Heat and life, as has been already pointed out, are inseparable. We cannot help producing a certain amount of heat if we are to go on living at all. Now, thanks to the fact that we wear clothes, our bodies live in an atmosphere of about 90 Fahr. that is 1 Geddes and Thompson, ■ Evolution of Sex,' 1889. a During pregnancy, however, the diet should be more abundant. INFLUENCE OF CLIMATE AND SEASON 49 to say, in what is practically a tropical climate. At this temperature the amount of heat produced in the body is in excess of its require- ments, even when that production is as small as is compatible with the full activity of our cells. This means that, even in a temperature of 90 , we are constantly wasting a certain amount of heat. Suppose, now, that one goes into the tropical regions. As the external temperature rises, the amount of heat which the body requires becomes less and less ; but already as little is being produced as is compatible with health, so that, in order to adjust the balance, one must not try to diminish the production by eating less food, but rather to increase the loss by wearing thinner clothes. In harmony with this, one finds, as a matter of fact, that the consumption of food by the inhabitants of the tropics is not notably less than that of those who live in the temperate zone. 1 Suppose, on the other hand, that one moves from a temperate to a colder latitude. The body will now require more heat to keep its temperature up to the normal level, and the first method had recourse to in order to meet the increased demand is by economizing waste, or, in other words, by diminishing the amount of heat lost. In practice, this is accomplished by an increase of clothing. If the external temperature falls still further, however, this method by itself becomes inadequate, and steps must be taken to increase heat production ; it is only then that it becomes advisable to consume more food. ' During the whole of our march,' says Sir John Franklin, in describing his journeyings in the Arctic regions, ' we experienced that no quantity of clothing could keep us warm while we fasted, but on those occasions on which we were enabled to go to bed with full stomachs we passed the night in a warm and comfortable manner.' Translated into physiological language, this means that the demand for heat in the body was so great that it could no longer be met by diminishing loss, but that the deficit had to be made up by an increase of heat production — i.e., by a greater consumption of food. What form the increased consumption of food takes is, com- paratively speaking, of little moment. All that is really necessary is that the number of Calories which the diet is capable of yielding should be considerably raised. As a matter of convenience, how- ever, and in order to avoid overfilling the stomach, it is best to have 1 It would seem, however, that the diet of tropical dwellers usually contains relatively less proteid and fat and more carbohydrates, especially sugar, than that of the inhabitants of colder regions. See a paper by Harvey W. Wiley, Med. News, 1904, lxxv. 945. There is some reason, also, to believe that in hot weather and in warm climates the digestive capacity is not so great as in colder, and that large quantities of food are consequently not so well borne. 4 50 FOOD AND DIETETICS recourse to fat as the principal source of the extra heat required, for fat is the compactest form of fuel we possess. Carbohydrates would serve the purpose equally well as far as the cells of the body are concerned, but one would require to consume more than twice as much of them as of fat in order to obtain the same amount of heat. Besides, in very cold latitudes carbohydrates are not so easily obtained as fat. This is the explanation of the enormous quantities of blubber which the Esquimaux consumes, us much as 20 pounds of flesh and blubber, we are credibly informed, being eaten in the course of a day in some cases. A similar adaptation to circum- stances on the part of Nature is seen in the milk of the walrus, which contains 40 per cent, of fat, thus supplying the young with an abundant and compact source of fuel, and enabling them to maintain their temperature in the icy waters of the North. The influence of season on the amount of food required is similar in kind to the influence of climate, though less in degree. In summer clothing should be diminished rather than food ; in winter warmer clothing should be worn, but the amount of food, and especially the proportion of fat which it contains, may with advantage be increased. Ranke found 1 that in order to keep his body- weight constant he had to eat as much food in summer as in winter. In the hot weather, however, the inclination to eat was less, and if he followed his appetite the fuel value of his diet fell by as much as 400 Calories per day. If, on the other hand, he disregarded his inclinations and ate enough to maintain his body-weight, his health suffered, a result which he attributes to an over-production of heat in the body. It would seem to follow from this that a slight loss of weight during the summer months is inevitable. Hirschfeld, criticising these results, 2 is inclined to attribute the bad effects which Ranke observed to follow the adoption of a full diet in hot weather to an over-consumption of proteid rather than to the richness of the diet as a whole. It certainly seems reasonable to avoid in warm weather what have already been described as the ' quick fuels ' — i.e., those nutritive constituents from which a large amount of heat can be produced in a short time, especially the proteids. For this reason, as well as on account of the fact that they are relatively rich in fat, the animal foods should be more sparingly consumed in summer, and the proportion of vegetable matters in the diet relatively increased. 1 ' Der Nahrungsbedarf im Winter und Sommer des gemassigten Klima ' (Zeit. f. Biologic, 1900. xl. 288). 2 ' Ueber Ernahrung in der heissen Jahreszeit und im Warmen KHma ' {Deut, Med, Woch., 1902, xxviii. 674). INFLUENCE OF IDIOSYNCRASY 51 5. Influence of Personal Peculiarity. There is a widespread impression that some people can 'get on' with less food than others, even although they are living under 1 identical external conditions. We hear it said of one man that he is always eating, and yet remains thin and languid ; of another, that he lives the life of an ascetic, and yet grows hearty and fat. To a large extent these apparent results are explicable by the differences of weight, build, and shape of body, which we have already studied ; but even giving such considerations their full weight, there remains some room for the belief that some people really do make better use of their food than others. To use a popular phrase, they ' put it into a better skin.' Scientific evidence on this point is very difficult to obtain. Remembering, however, that the utilization of food is a function of living protoplasm, it is at least conceivable that in some persons the activity of the cells is greater than in others, and leads to a more rapid breaking down of food and a greater waste of heat. 1 It has been clearly proved by scientific experiment that a man who is skilled through long practice in doing any particular piece of muscular work will do it with less expenditure of bodily material, as expressed in the excretion of carbonic acid and nitrogen, than a novice. In other words, and as far as that particular kind of work is concerned, the former is a more economical machine than the latter, and there is really no very apparent reason why there should not be degrees of such economy in the performance of all the functions essential to life. The influence of the nervous system in regulating tissue waste must also be borne in mind. The functions of nutrition and assimilation seem in some mysterious way to be under the dominion of the central nervous system, and if the control so exercised is diminished there may be a tendency to increased waste of tissue, just as there is in a paralysed limb. But the degree in which the nervous system exercises its functions differs enormously in different persons, and so it is not altogether incredible that the degree in which bodily waste is controlled may differ also. Be this as it may, there is no more practical fact in dietetics than the different results which the same food, either in quantity or in kind, produces in different persons, and it has to be constantly borne in mind in regulating the diet of the sick. A study of the habits 1 For a criticism of this view see Rubner's ' Beitrage zur Ernahrung im Knaben- alter ' (Berlin, 1902). 4—2 52 FOOD AND DIETETICS of different nationalities reveals the same thing. The German is notoriously a larger feeder than the Frenchman, a fact which was clearly evidenced in the commissariat arrangements in the Franco- Prussian War, and Americans certainly consume more food per head than Englishmen in the same conditions of life. Even granting, which might be disputed, that the output of work and energy is greater per individual in America than in Europe, the difference is not entirely explained, and may perhaps rest on some inherent con- stitutional cause. Anyhow, a consideration of facts such as these should warn one of the dangers of dogmatism in matters of diet. We can and may lay down rules as to the kind and amount of food required under different circumstances, but we are treading on dangerous ground when we come to apply these rules to individual cases. In the matter of diet every man must, in the last resort, be a law unto himself ; but he should draw up his dietetic code intelli- gently, and apply it honestly, giving due heed to the warnings which Nature is sure to address to him should he at any time transgress. Having considered the kind and quantity of food required in health, and the way in which these are affected by various bodily conditions and states of life, we may now glance for a moment at the general effects of an excessive or a deficient supply of food respectively. Overfeeding. — It is, perhaps, no exaggeration to say that the tendency of civilized peoples, and especially of the upper classes in civilized society, is to eat too much. Feeding is pleasurable as well as necessary, and when the necessities of the body have been sup- plied, the process is apt to be continued merely for the sake of the pleasure which it affords. Now, a moderate excess of food is prob- ably harmless, if not actually beneficial. It is not safe to sail too near the wind in matters of diet. As a French writer has paradoxica^y put it : 'Pour avoir assez il faut avoir trop.' For it is well to have some reserve in the body which can be called upon if one is compelled for any reason to go for some time without any food at all. The presence of such a reserve can only be insured by the habitual consumption of rather more food than is required to meet the bare necessities of the body. It is in this way, too, that the occasional indulgence in an unusually heavy meal can be justified. There are some, for instance, who see in the large Sunday dinner of the workman a partial provision for the wants of the whole week. Leaving aside the consideration of this surplus, which can hardly be described as an excess, one has to look at the results of acute and OVERFEEDING 53 chronic overfeeding separately. The injurious effects of consuming a great excess of food at one time are local rather than remote. They fall chiefly upon the digestive organs. The overburdened stomach may relieve itself by vomiting, or, if the food is passed on into the intestine, it is apt to undergo decompositi m before it is all absorbed, and be carried off by diarrhoea. That these effects may sometimes be sufficiently severe is evidenced by the fact that people have been known to die of a ' surfeit,' though in modern days such a result must be regarded as very rare, always excepting those instances in which even moderate overloading of the stomach may have too much hampered the action of a feeble heart. If the process of absorption goes on too rapidly for assimilation to keep pace with it, the blood seems to be able to rid itself of some, at least, of the surplus products of digestion by aid of the kidneys. Thus, a great excess of proteid in the food may give rise to transient albuminuria, while sugar may temporarily appear in the urine after an extravagant consumption of carbohydrates. This method of adjusting the balance, however, seems to be one which is but seldom had recourse to. The general results of habitual or chronic overfeeding are more insidious, and seem to vary with the nutritive ingredient which is specially indulged in. If this be carbohydrate or fat, the surplus is simply stored up in the form of fat, and obesity results. In the case of proteid such storage is hardly possible, for so great is the tendency of ' nitrogenous equilibrium ' to assert itself that the body can only ' lay on ' proteid for very short periods, unless the process of growth is still going on. What usually appears to happen is that the surplus proteid is split up into two portions, one of which contains most of the carbon and is probably converted into fat and stored in that form, while the nitrogen-containing part is broken down, but not, perhaps, very rapidly and completely ; so that the products which represent the intermediate steps in its destruction circulate for some time in the blood before being excreted in the form of urea. It may be that some of these products are concerned in the production of such conditions as granular degeneration of the kidneys, high arterial tension, gout, and rheumatism ; but that is a point on which it is not yet advisable to speak very dogmatically. It must be remembered, too, in this connection that an excess of proteid sparers in the blood may produce very similar results to an excess of proteid itself by shielding the latter from complete and rapid oxidation. Underfeeding. — It is astonishing how long the body can go without 54 FOOD AND DIETETICS food provided a due supply of water is obtainable. Lunatics have been known to refuse food for four or five weeks at a stretch, and the experience of professional fasters shows that long periods of starvation can be borne with impunity. Experiment, indeed, has shown that it is only when the weight of the body has fallen to one- half or one-third its original amount that death from inanition ensues. It is well to remember these facts when dealing with cases of acute disease. A doctor is very apt to flatter himself that he is keeping a patient alive by rectal feeding, for example, when all the time the patient is really living on his own tissues. Nor need one be unduly alarmed if a well-nourished patient is unable to take any food at all for a few days. His own reserves will be able to tide him over the emergency without much injury. Of chronic or habitual underfeeding as a whole it may safely be said that it is more injurious than the opposite condition of intem- perance in food. One has to recognise also that a relative lack of one nutritive constituent is probably commoner than a deficiency of all, or, in other words, that an ill-balanced diet is more frequently met with than one which is defective all round. As nitrogen is the element of which the body is mainly built up, a lack of proteid in the food seems to be more injurious than a shortcoming in respect of carbohydrate or fat. As this point has already been referred to (p. 24), it need only be repeated here that an insufficient supply of proteid leads to imperfect tissue repair, more especially, perhaps, of the muscles and blood \ l that it causes the body to become unduly watery, whence the pallor and puffiness of the underfed ; and that the combined effect of these results is to produce a lowering of the power of resistance to unfavourable influences, including disease. 2 It must not be concluded that merely because a man is fat he cannot at the same time be underfed. On the contrary, obesity is quite compatible with an insufficient supply of nitrogenous nutri- ment, and many of the most intractable cases of corpulence — those, namely, in which the patient is pale and flabby as well as fat — are just those in which the nitrogenous tissues of the body are to be regarded as being in a state of imperfect formation and repair. It 1 For experimental evidence, see Subbotin, Zeitsch. fur Biologic, 1871, vii., p. 185. 2 For information on the part played by habitual underfeeding in the produc- tion of physical deterioration, see evidence by the writer and others in the Report of the Interdepartmental Committee on Physical Deterioration (London : Eyre and Spottiswoode, 1904). UNDERFEEDING 55 is probably for this reason that fat persons often stand depletory measures, such as purging and bleeding, worse than those who are in appearance not so well nourished. The effects of insufficient feeding in diminishing resistance to cold have already been alluded to (p. 49), and were strikingly seen in some episodes of the American Civil War, a detailed account of which has been provided by Flint. 1 Its effects in producing liability to disease were well illustrated in the outbreaks of relapsing fever and typhus which followed the potato famine in Ireland 2 in the early part of this century, and similar results have repeatedly been wit- nessed in India and elsewhere, fever and plague dogging the foot- steps of famine. It has also been pointed out that exposure to infection is specially apt to be dangerous on an empty stomach, as, for example, before breakfast, a fact which it is specially important for members of our profession to bear in mind. The tubercle bacillus seems to find a specially favourable soil in ill-nourished persons. The association between bad feeding and such diseases as phthisis and scrofula is well established, while an improvement in nutrition is not infrequently followed by their cure. This may be the reason why diabetics, who live in a chronic state of partial starvation, are so liable to tuberculosis, and tall men, who, for reasons already discussed, have less food to spare than their fellows of less stature, ars believed to be more subject to consumption than the latter are. Epidemic ophthalmia is another disease which seems prone to select the underfed as its victims, and it might be well when it breaks out, as it is so apt to do, among the children of Poor Law schools and other public institutions, to look more to the possibility of defective diet and less to overcrowding as the cause. It is considerations such as these which entitle one to regard the repeal of the Corn Laws, which has done so much to cheapen food in this country, as a hygienic quite as much as an economic measure, and the diminished death-rate which has been so conspicuous in the latter part of the last century may have had more to do with it than one commonly thinks. 3 There is reason to fear, however, that large sections of the com- 1 ' Physiology of Man,' New York, 1867, p. 35. a See Life of William Stokes in ' Masters of Medicine ' Series, p. no et seq. 3 For particulars of the enormous all-round improvement which has taken place in the abundance and variety of the diet of agricultural labourers in this country in the last half-century, see a paper on ' Agricultural Wages in England and Wales' during the Last Fifty Years,' by A. Wilson Fox (Journ. Roy. Statist. Soc, J903, lxvi. 273). Similar information will be found in the volume entitled ' Labour 56 FOOD AND DIETETICS munity in this country are still habitually underfed. Observations on the diet of labourers in Edinburgh x showed that it contained on an average only 1077 grammes of proteid, as against Atwater's standard of 125 grammes, and an energy value of only 3,228 Calories, as opposed to the 3,500 which he believed to be necessary for a man doing a moderate amount of muscular work. Mr. Seebohm Rown- tree's inquiries into the diet of a corresponding class in York 2 yielded similar results, the energy value being 17 per cent., and the proteid average no less than 29 per cent, below standard requirements. There is urgent need for more extended studies on similar lines to these. 3 Meanwhile, it may be pointed out that the defects above indicated are due not so much to poverty as to ignorance ; not to buying too little food, but to buying the wrong articles. The Edinburgh investigators were of opinion that in order to improve the dietary of the labouring classes the following principles should be instilled into them : 1. That a diet of tea and bread or of tea, bread, and butter (the lazy diet) is faulty. 2. That the faults of the tea and bread diet can be corrected by the free use of meat, eggs, or other animal food, but that this mode of correction is expensive. 3. That the faults can also be corrected by the free use of oatmeal with milk, or of peas or beans, without extra cost. The bad effects of underfeeding fall most heavily upon the young, for the greater the demand on the part of the body for food, the more severely is any deficiency felt. 4 The recognition of this fact is as old as Hippocrates, who devoted a special aphorism to the statement of it. « Old men,' it runs, ' bear want of food best ; then those that are adults ; youths bear it least, most especially children, and of them the most lively are the least capable of enduring it.' and Protection,' edited by H. W. Massingham (London : T. Fisher Unwin, 1903). For statistics on the fall in the price of food in recent years, see Memoranda, etc., on British and Foreign Trade and Industrial Conditions (London: Eyre and Spottiswoode, 1903). . 1 Loc. cit. 2 ' Poverty : A Study of Town Life ' (London : Macmillan and Co., Ltd., 1903, new edition, p. 234). 8 For earlier studies of diets in this country, in which, however, the carbon and nitrogen standard was employed, see ' On the Dietaries of Scotch Agricultural Labourers ' and ' On the Economic Condition of the English Agricultural Labourer,' by Robert Hutchison, F.R.S.E. (Trans, of the Highland and Agri- cultural Society of Scotland, 1867 and 1871). Also Oliver, ' The Diet of Toil,' a paper read at the Congress of Hygiene and Demography, Buda-Pesth, Sep- tember, 1894. For references to some more recent dietary studies in this country see p, 34. * See ' Feeding in Relation to the Health of the Young,' by James Niven, M.A., M.B. (London and Manchester : §herratt and Hughes, 1904). UNDERFEEDING 57 The remote results of underfeeding are not less injurious than its more immediate effects. Amongst such results, impairment of digestive power is very conspicuous. 1 The danger of stuffing a starving man is notorious, but even in chronic underfeeding the same weakening of the digestive organs is observed. It is often seen in dyspeptics. The more their nutrition fails through not eating, the less they are able to digest, and the first step in curing their stomach troubles must often be in the direction of compelling them to eat more. Another of these remote dangers is in the influence of imperfect feeding upon the mind. I refer not merely to a lowering of mental power, but to that feeling of dissatisfaction, discomfort, and depres- sion, culminating sometimes in madness and hallucinations, which imperfect nutrition of the brain is apt to produce. ' A hungry man is an angry man,' and the proverbial good nature of the Englishman may, perhaps, be associated with the fact that, as a rule, he is full fed. The dangers here alluded to have been eloquently described by Dr. King Chambers 2 in the following passage, with which I may close this chapter : ' Deficient diet, like all morbid conditions, both corporeal and mental, is a vitiating and degenerating influence. Famine is naturally the mother of crimes and vices, not only of such sort as will satiate the gnawing desire for food, but of general violence and lawlessness, ill-temper, avarice, lust, and cruelty. 'The love of purposeless destruction exhibited by the Parisian Communists in our own day may be fairly credited to deficient food. No well-fed people could have wrecked the Vend6me Column or burnt the Town Hall and Tuileries, of which they were so proud. They were like hungry children smashing their dolls. And Thucydides, Boccaccio, and Defoe are all agreed as to the hideous wickedness exhibited at Athens, Florence, and London during their famine-fevers. The exceptional instances are those where individuals or nations have conquered by courage and self-restraint their natural selfishness, and have made the interests of others paramount to their own. Am I blinded by love of my country, or may I justly quote the history of the Lancashire cotton-famine as a case in point ?' 1 It is an interesting question whether the effect of town life in impairing digestive power may not be partly responsible for the habitual underfeeding so often found in the industrial section of urban communities. It is possible, in other words, that the town worker may in many cases be incapable of digesting enough food to keep him in an ideal state of physical efficiency. 8 'Manual of Diet in Health and Disease,' second ed: edition, 1876, p. 223. £ 58 } CHAPTER IV ANIMAL FOODS In previous chapters we have dealt with foods in general. We have studied the nature and uses of their nutritive constituents, the standards by which one judges of their relative values, the amount of food required to maintain the body in a state of health, and the directions in which this amount must be modified in accordance with various influences and conditions. We have also glanced at the general results of over and under feeding. In this and a number of succeeding chapters we shall undertake the study of individual foods in detail, and in dealing with each shall consider (i) its physical structure and chemical composition ; (2) its behaviour in the stomach and intestine ; (3) its nutritive value in the body; (4) its true economic worth. We may begin our studies with foods derived from the animal kingdom; but it will be well to defer the consideration of the general characters of the group as a whole until we are in a position to contrast them with the vegetable foods. A convenient classification of the animal foods is as follows : 1 . Meat, including the several varieties of butcher's meat, poultry, game, and ' offal.' 2. Gelatin and the foods prepared from it (jellies). 3. Soups, beef-extracts and beef-powders, beef-tea and beef-juices. 4. Fish and its allies. 5. Milk and its derivatives, including cream, butter, and cheese. 6. Eggs. 1. Meat. We may look first at the physical structure or architecture of meat (Fig. 4). If one examines a piece of boiled meat, it will be found that it can easily be torn into a number of long, stringy fibres. On micro- ANIMAL FOODS 59 scopic examination, these would be found to be made up in their turn of bundles of microscopic tubes, known to the histologist as muscle fibres. The fibres vary in length in different kinds of meat. Sometimes they are short, as in the breast of a chicken ; at other times they are much longer, as in the leg of a crab ; and the shorter they are, the more tender and easily digested the meat is. Meat should be cut or carved at right angles to the long axis of the i. ^res. It is then more easily chewed, and, the contents of the tubes being exposed, the flavour is increased, while the action of the digestive juices is facilitated. The walls of the tubes consist of an albuminoid substance (elastin), while the connective tissue which holds together the fibres is chiefly composed of a material called ' collagen,' which yields gelatin on boiling. The older an animal is, and the more work its muscles have had to per- form, the denser is the connective tissue and the thicker the walls of the tubes. The latter fact was long ago pointed out by Dr. Kitchiner in his ' Cook's Oracle.' F,c; ( . Diagrammatic Re- ' That exercise produces strength and presentation of the firmness of fibre,' he says, 'is excellently Structure of Meat. ^ exemplified in the woo dcock and - M rSSSi.'kSSS ,b: P artrid S e - The f0rmer flieS m0St > the latter walks ; the wing of the woodcock is always very tough, of the partridge very tender ; hence the old doggerel distich : If the Partridge had but the Woodcock's thigh, He'd be the best bird that e'er doth fly.' Embedded in the connective tissue between the fibres is a variable amount of fat. Sometimes it is almost entirely absent— e.g., in most forms of game and in the breast of the chicken ; at other times the amount of fat so placed is quite abundant. This is the case in pork, in highly-fattened beef or mutton, and in swimming birds, such as the duck and goose, which require a large store of fat, both to lighten the body and as a source of heat. A large amount of fat tends to 60 FOOD AND DIETETICS diminish the digestibility of meat, apparently by forming a sort of waterproof coating around the fibres and hindering their solution by the gastric juice, and it is notorious that pork, duck, and goose are rather indigestible forms of flesh. The contents of the microscopic tubes or muscle fibres consist of water holding in solution proteids, salts, and the substances known as ' extractives,' the whole constituting muscle-juice. The younger the animal, the more water does its flesh contain, and the lower is its nutritive value. This may be the explanation of the German saying, ' Calf-meat is half-meat.' The chief proteids which the juice contains are myosin, muscle albumin, and haemoglobin, the first being the most important. Myosin has the property of clotting after death, the hardening of the muscle which results being known, it will be remembered, as rigor mortis, or death-stiffening. Meat in that condition is tough, and accordingly, if tenderness is desired, the meat should be eaten either immediately after the animal is killed, and before rigor mortis has had time to set in, or else it should be allowed to hang till the rigor has passed off. The disappearance of rigor is due to a re- solution of the myosin by the development of acids, 1 and to a partial digestion of it by the traces of pepsin which muscle contains. The process must be regarded as an early stage of putrefaction, and, as is well known, if the meat be allowed to hang for some time longer it becomes ' high.' The acids which develop in meat on hanging aid the gelatinization of the connective tissue which occurs on boiling, and also improve its flavour by removing the rather insipid flatness of taste which characterizes very fresh meat. In the flesh of animals which have undergone great muscular exertion immediately before being killed there is a considerable quantity of acid present even at the time of death. Hence the flesh of hunted animals is of a superior flavour, and in less humane ages and countries attempts have been made to develop this flavour in domestic animals artificially by urging them to frantic exertions before slaughter. Another way of producing these effects by artificial means is by soaking the meat in vinegar and water for a short time. This is found to improve the flavour of fresh meat, as well as its tenderness. It is partly for the same reason that the use of vinegar favours the digestibility of the hard muscles of the crab and lobster. The amount of haemoglobin, or red colouring matter, in the juice varies greatly in different kinds of meat, and is usually less in 1 Sarcolactic acid and acid phosphates. CONSTITUENTS OF MEAT 61 amount in that obtained from young animals. It is of importance as containing iron. Haemoglobin is also found in the small blood- vessels which form a network around the fibres of meat. In animals which have been bled to death it is much diminished in amount or altogether removed ; hence the pallor of veal. The chief mineral substances found in the juice of meat are phos- phoric acid and potash. Meat must be regarded as one of the principal sources of these valuable building materials in the diet, and if they are insufficiently supplied, the muscles are flabby and badly developed. Last, but not least, of the substances contained in solution in the juice of meat are the extractives. These are so called because they can be ' extracted ' from meat by means of boiling water, and are familiar to everyone as the dark brown, sticky material which con- stitutes the chief part of Liebig's Extract. We shall have much to learn about these extractives later on, but it may be stated here that their exact chemical nature is to a large extent unknown, that they have no nutritive value, but are of importance as being the chief cause of the characteristic taste of meat, and that, therefore, when they are removed, as they are, for example, on prolonged boiling, the meat becomes flavourless and insipid. Further, it would appear that the characteristic flavours of the different kinds of meat are due to minute differences in the amount and kind of the extractives present. The age of the animal and the way in which it is fed are of great importance in this connection. The flesh of full-grown animals is richer in extractives and has a fuller flavour than the flesh of those which are immature, which explains why we eat lamb with mint sauce and add spices to veal. The influence of feeding, on the other hand, is well illustrated by all forms of game. The flesh of wild rabbits, which eat aromatic herbs, especially thyme, has a much finer flavour than that of rabbits which are fed by hand, and a slice of wild duck is generally admitted to be a more tasty morsel than a piece of the bird reared in a farmyard. Every- one knows, too, how ' fishy ' sea-birds taste, how superior hill mutton is to its turnip-fed substitute, and how in grouse or caper- cailzie one can detect, as it were, an echo of the aroma of the heather-tops or pinewoods amongst which these birds live. The chemical composition of meat varies considerably, depending as it does on the particular ' cut ' examined, on the breed of the animal, and on the degree to which it has been fattened. It must be noted, also, that by no means the whole of ordinary butcher's meat consists of edible matter, a large part being made up of bone, gristle, tendon, and to FOOD AND DIETETICS other inedible portions. In an average piece of meat these waste matters may be reckoned at 15 per cent, of the whole, and the proportions of the constituents in the edible part are about as follows (Konig) : Water . . . . . . 75 to 77 per cent. Muscle fibres .. .. 13 to 18 „ Connective tissue . . . . 2 to 5 „ Fat J to 3 Ash 08 to 18 „ Extractives.. .. •• i » Other analyses represent the proportions of the chemical sub stances present thus : 100 Parts of Lean Beef without Visible Fat (Bischoff and Voit). Proteid 1836 Gelatin .. .. .. 164 Fat . . . . . . 090 Extractives .. .. 190 Ash .. .. .. 130 Water 75'9° 100 Parts of Dry Substance (Rubner). Syntonin, myosin, and gelatin 70-1 Haemoglobin and serum albu- min 857 Muscle albumin .. .. 313 Extractives . . . . . . 1268 Ash 550 The effects of fattening are shown in the following table, in which the composition of lean, medium, and very fat beef are stated in round numbers : Water. Nitrogenous Matter?- Fat. Ash. Lean.. .. 765 21 15 1 Medium .. 73 20^5 55 1 Very fat 53 17 29 1 The chief points to note in this table are : (1) The large amount of water which meat contains. About three-quarters of its total weight is made up of water, or, stated otherwise, 1 pound of meat contains '£ pound water and J pound of nutriment. It has been already pointed out that the flesh of young animals is relatively richest in water. (2) The relation between water and fat. The more there is of the latter present, the less there is of the former ; in other words, when fat is deposited in a muscle, it replaces water, and not proteid, and so the gain in nutritive value is an absolute one, and is not attained at the expense of a loss of nitrogenous con- stituents. The above analyses refer especially to beef ; the composi- tion of the other commoner sorts of meat and some varieties of game may be graphically represented as follows : 2 1 'Nitrogenous matter' is the figure obtained by multiplying the amount of nitrogen in 100 parts by 6-25 ; i.e., it is assumed that it is all proteid. In reality 15 per cent, of the total nitrogen is present in the form of extractives, the amount of which can be calculated by multiplying their nitrogen by 312 (Stutzer's factor). a Most of the analyses from which the diagram is constructed are by Konig and Stutzer. The analysis of lamb is from Atwater, that of bacon from Church. CONSTITUENTS OF MEAT 63 WATER. | J PROTEID & vzm), GELATINE. HHi FAT.I ASH. The following table shows the composition of the commoner poultry : * COMPOSITION OF POULTRY. Fowl, young : Dark meat . . . . . . . . . • Light meat Giblets Turkey : Dark meat Light meat . . . . • . • • Giblets Duck: Meat, not including breast or giblets . . Breast Giblets Goose : Meat, not including giblets Giblets Water. Proteid. Fat. 70-1 7° '3 710 20-8 219 19-8 8-2 7'4 6-4 57-o 639 567 21-4 257 177 20 '6 94 23'5 55'5 73 9 73'2 174 22'3 179 26 'I 2'3 5-o 518 700 l6'2 20'I 31 - 5 82 Ash. 12 I'l 1 '3 I'l 1*3 10 i'3 1-8 10 17 1 United States Department of Agriculture, Farmers' Bull. No. 234. 64 POOD AND DIETETICS It must be clearly realized that these results are merely approxi- mative, and may vary considerably in different cases. Thus, in very young calves the amount of water in the flesh may be 80 instead of only 71 per cent. The relative proportions of gelatin and proteid also fluctuate considerably. The proportion of the former is highest in the flesh of young animals — hence the value of veal as a basis for soups — and is lowest in game. As regards the amount of the extractives, but few data are available, but the latest investigations tend to show that the red meats are richest in these constituents. 1 Hitherto we have been dealing with the structure and composition of meats in their raw state, and we must now direct our attention to the changes which are effected in them by cooking. The full con- sideration of this subject may be conveniently deferred to another chapter (Chapter XXII.), but at present one may note that the general effect of cooking on the structure of meat is (1) to loosen the fibres by converting the connective tissue which holds them together into gelatin, and (2) to remove some of the fat, the exact proportion lost depending on its melting-point, and being higher in cake-fed than in pasture-reared animals". The chief effect of cooking on the chemical composition of meat is to diminish the amount of water which it contains. This results, curiously enough, even when the meat is boiled. This is important, for it means a very considerable increase in the nutritive value of cooked, as compared with raw, meat, a result which is the very reverse of that which follows the cooking of vegetables (p. 405). In consequence of this loss of water, an ordinary plateful of cooked meat, weighing 4 ounces, may be regarded as equivalent to 5 ounces of raw meat. Another effect of cooking on the chemical composition of meat is the removal of part of the extractives. This is most marked when boiling is the method employed, but it also occurs to a considerable extent even in roasting. Some of the salts are also dissolved out by boiling, and reference has already been made to the fact that cooking removes some fat as well. These general effects of cooking are illustrated in the following analyses by Konig of a piece of meat before and after cooking: 2 1 Adler, Berlin Klin. Woch., 1908, xlv. 393. 2 For further information on this subject, see ' Experiments on Losses in Cooking Meat,' by H. S. Grindley and Timothy Mojonnier, United States Department of Agriculture, Office of Experiment Stations, Bull. No. 14I, 1904. DIGESTION OF MEAT 65 Water. Nitrogenous Matter. Fat. Extractives. Mineral ■ Matter. Beef: raw boiled roasted Veal cutlets : raw roasted 70-88 56-82 55-39 71 '55 57'59 22-51 34 -I 3 34'23 20-24 29-00 4'52 7'5° 8-21 6-38 "■95 0-86 0-40 0-72 o-68 0-03 1-23 I -15 1-45 I -15 I '43 The following results were got by Tankard. 1 They represent the composition of various kinds of meat cut from the cold roast joint, and wholly edible. They include such a proportion of fat as would , be commonly helped and eaten with the lean, but are exclusive of skin, gravy, and dripping : Mutton. Lamb. Beef. Veal. Pork. Duck. Fowl. Water (dried at 100° C.) Fat (ether ext.) Proteids (N x 63) 3976 26-80 29 04 1 "93 59-89 n-95 24-69 1 -63 45-63 24-21 26-50 I -21 51-88 "•39 32-19 i-57 44-90 19-67 32-63 1-86 64-13 6-06 27-12 2-04 67-40 6-68 24-26 i-37 1 97-53 98-16 97-55 97-o3 99-06 99-35 99-71 -45" -7 5 FAT. PROTEID. 71 Taking Konig's figures, the composition of raw and boiled beef may be graphically compared as in Fig. 6. 2. Digestibility and Absorption of Meat. All solid foods are digested in the stomach in a physical sense ; that is to say, they are reduced to a fluid or pulp, in which condition alone they are able to pass on into the in- testine. But meat is a food the main share in the chemical digestion of which also falls to the lot of the stomach ; that is to say, its chief nutritive constituent (proteid) is there got into a form fit for absorption. Now, it may be laid down as a rule that the greater the extent to which the chemical digestion of a food goes on in the stomach, the easier does its mechanical digestion prove. Hence, although meat makes considerable demands on the gastric juice, it does not throw any great strain on the mechanical resources of 1 Allen's ' Commercial Organic Analysis,' iv. 269, second edition, 1898. 5 67 WATER. raw. boiled. Fig. 6. — Comparative Composition of Raw and Boiled Beef. 66 FOOD AND DIETETICS the stomach, and for that reason it must be regarded as among the more easily digested of the solid foods. The first change which takes place during the digestion of meat is that the fibres swell up and become softened ; their colour then changes to a grayish-yellow ; they fall apart, and the mass becomes pulpy. Last of all, the individual fibres split up either into longi- tudinal threads or transversely into discs. It will be evident that the ease with which these changes can occur must depend on many conditions. The harder and densrr the connective tissue which holds together the fibres, the less readily will they separate, and the greater the amount of fat between the fibres, the less readily can the gastric juice act upon the latter, hence the indigestibility of tough and fat meats. The longer and thicker the individual fibres, the more slowly are they split up ; hence the improvement in the digestibility of tough meat which results from breaking up the fibres by pounding the meat across its cut ends. The influence of cooking also is of great importance. It has been found by experiments on man 1 that 3^ ounces (a small helping) of beef disappears completely from the stomach in the following times, depending on the method by which it has been cooked : Raw Half boiled . . Wholly boiled Half roasted Wholly roasted 2 hours. 2* ,. 3 ■> 3 .. 4 .. Artificial experiments outside the body corroborate these results. Popoff 2 found that the proportions digested in a given time were as follows : Raw . . . . . . 100 parts. Boiled 834 „ Smoked .. .. .. 71 ,, Boiled and smoked .. 606 ,, Stutzer 3 found that, of 100 parts, there is dissolved in half an hour : Raw. Boiled. By weakly acid juice .. .. 892 per cent. 38 7 per cent. By normal juice .. .. 969 „ 793 ,, Similar experiments by Chittenden and Cummins 4 confirm these conclusions, and the only experiments with which I am acquainted which resulted differently were some by Uffelmann 5 on a boy with a gastric fistula, in whom it was found that raw meat was digested 1 Jessen, Zeit. fur Biologic, 1883, xix. 129. 2 Popoff, Zeit. fur Physiol. Chemie, 1890, xiv. 524. 3 Weyl's ' Handbuch der Hygiene,' Bd. iii., p. 216. 4 American Chemic.al Journal, 1884-85, vi. 318. 5 Deut. Archiv. fur Klin. Med., 1877, xx. 535. DIGESTIBILITY OF MEAT 67 rather more slowly than roast, although the fibres of the latter fell apart more rapidly. On the whole, one may conclude that most forms of cooking tend to lessen the digestibility of meat in the stomach, a conclusion which applies, almost without exception, to all forms of animal food, but is quite the reverse of true as regards vegetable foods (see Chapter X.). In accordance with these experimental results one finds that raw, or at all events much underdone, meat is a form of food which patients with very weak stomachs can digest more easily than most other forms of nourishment. The best method of preparing such meat is by scraping a piece of tender juicy steak with a blunt instrument in a direction parallel to the course of the fibres. This separates out the fibres from the enclosing connective tissue, and leaves the latter behind. The fibres form a pulp which can be seasoned with celery, salt, and a little pepper, and served either as a sandwich or stirred into broth. In what is known as the Salisbury cure another method of administration is adopted. The meat is chopped very thoroughly, all visible connective tissue and gristle being removed, and it is then made into little cakes ^ to 1 inch in thickness, and of 3 or 4 inches diameter. These are placed in a clean frying-pan, strongly heated, but without either water or grease. When one surface of the cakes is seared they are turned over and the other heated similarly. They are then covered and set on the side of the fire till the red colour of the meat has been changed to a drab. They are finally seasoned with a little fresh butter and salt, and are ready to be served. As regards the relative digestibility of the different kinds of meat, there are but few exact data available. ' There is a general impression that mutton is more easily digested than beef, which some have attributed to the finer fibres and looser connective tissue of tn© former. Jessen, however, found that 3J ounces of raw mutton were digested in precisely the same time as an equal weight of beef; while the experiments of Chittenden and Cummins showed that the digestibility of mutton, outside the body at least, was inferior to that of beef (92 as compared to 100). They admit, however, that the results varied greatly in different samples owing to age and other conditions. There can be no doubt that mutton fat, especially when hot, is particularly apt to prove irritating to the stomachs of some persons, and in them the eating of such articles as mutton pies or Irish stews is prone to be followed by an attack of acute gastric catarrh. Veal is believed to be somewhat difficult of digestion, a belief 5—2 68 FOOD AND DIETETICS which is confirmed by experiment, for it required two and a half hours for its digestion, as compared with two hours for beef (Jessen). The difficulty of digesting veal is somewhat surprising, for the connective tissue, though abundant, is very easily changed into gelatin. It is believed by some that the explanation is to be found in the ease with which the fibres of veal elude the teeth on mastica- tion; the rather insipid taste of veal may also be a contributive cause, for such foods do not tend to excite a free flow of gastric juice. The comparative indigestibility of pork is shown by the fact that 3-J ounces of it required three hours for their complete digestion, as compared with two hours for beef. The difficulty here is fully accounted for by the large accumulation of fat between the fibres. On the other hand, the fat of bacon seems to be in a granular form, which is not difficult to digest, and it can often be eaten with impunity by persons to whom other forms of fat are intolerable. For this reason bacon is an invaluable aid in feeding delicate children and diabetic or phthisical patients in whose diet the free use of fat is indicated. The breast of chickens and game is amongst the most digestible forms of meat, but the leg muscles are often very tough. Very fat poultry should be avoided by the dyspeptic, as the fat of such birds is particularly apt to become rancid. Lastly, it must be pointed out, in connection with the relative digestibility of different sorts of meat, that idiosyncrasy plays a very large part in the process. There are persons, for instance, whom mutton invariably makes ill, while they can eat beef with impunity, and others who can take mutton, but cannot touch beef. No explanation of such cases can be given. Ilie absorption of meat has already been referred to (Plate II.). It was shown that only about 5 per cent, of the organic matter in meat fails to enter the blood, and that as the result of this meat is a food which leaves a very small residue in the intestine. This gives it a special value in some cases of intestinal disease. 3. Nutritive Value and Economy of Meat. The principal nutritive constituent of meat is proteid, and it is as a compact and easily digested source of this that meat is chiefly of value. Meat is thus one of the best sources of building material for the body. We have also seen that proteid is characterized by the rapidity with which it can be broken down by the cells with the DIGESTIBILITY OF MEAT 69 liberation of heat, or, in other words, that it is a ' quick fuel.' It is to this fact, probably, that meat owes the ' heating ' qualities commonly ascribed to it, and for a similar reason its use should be restricted in hot weather. The use which is made of meat in training has, been justified on the same grounds (p. 38). Another characteristic of proteid is that it seems to exert a stimulating effect on the cells and on the body generally, and the feeling of well-being which follows a meat meal may be put down to this cause. In savages who are unaccustomed to meat the free consumption of it is said sometimes to produce a nervous excitement amounting almost to intoxication. For this reason, too, the presence of much meat in the diet seems to act as an exciter of the animal passions, and an eminent authority 1 has advised that in the treatment of cases in which such propensities require to be kept in check one should ' avoid flesh, as the incarnation of rampant, uncontrollable force.' Meat is one of the few articles of diet on which life can be supported alone for an almost indefinite time. It cannot, however, be regarded as constituting in itself anything like a perfect food. It is relatively much too rich in proteid and too poor in other nutritive constituents. It would require about 4^ pounds of it a day to supply the energy required, and such a quantity would be apt to damage the digestion, besides overloading the blood with nitrogenous waste products. The almost exclusive use of lean meat is the basis of the ' Salisbury cure,' 2 to which reference has already been made, and it has also been recommended as a means of treating some diseases of the skin — e.g., psoriasis 3 — which have resisted the ordinary remedies. The use of meat in such diseases as diabetes, gout, and obesity, will be dealt with in another chapter. The relative nutritive value of different sorts of meat depends chiefly on the amount of fat they contain. Fat, as we have seen, replaces part of the water, and not the proteid, of the leaner meats, and thus the fat meats are better sources of fuel than the latter, while not inferior to them in building material. Apart from this, the nature of the extractives present may perhaps have some influence on general metabolism. Dr. Smith 4 tells us that Kean, the famous actor, used to adapt the kind of meat he ate to the part he had to play, choosing pork for tyrants, beef for murderers, and mutton for lovers. This may seem far-fetched, but it may indicate that there 1 Clouston, ' Insanity,' p. 520. See also Mr. Eustace H. Miles' ' Better Food for Boys ' (London : George Bell and Sons, 1901). a ' The Relation of Alimentation and Disease '; Salisbury, New York, 1895. 8 Parkes, Lancet, 1874, i., p. 722. 4 Food, p. 52. 76 FOOD AND DIETETICS are subtle differences in the different kinds of meat which chemistry does not enable us to detect, but which are yet not without influence upon the body. From an economic point of view meat is a dear food. This is clearly shown in Plate III., and holds good whether one regards .meat merely as ayielder of energy or as a source of building material. It is for this reason that the consumption of meat is much greater amongst the upper classes in this country than it is amongst the lower. Thus the average number of pounds of meat eaten per head per week by artisans, mechanics, and labourers is 2*06, by the lower middle class 2*35, by the middle class 3'5o, and by the upper class 577. The costliness of it, however, can be considerably diminished by selecting the cheaper ' cuts,' which are equal in nutritive value to the dearer kinds, though inferior in tenderness and flavour. The question of waste from bone, etc., must also be considered. Thus, in the case of mutton and pork, the leg contains relatively less bone than the shoulder, and in beef there is a much larger proportion of bone in the shin than in the round, and of these the least bony parts will be the most economical from a nutritive point of view. Much, too, can be done to diminish the cost by the use of the cheap frozen meats which are now imported. These are equal in nutritive value to fresh meat, and are only slightly inferior to the latter in keeping qualities. They are not drier than ordinary meats, as is often stated, for chemical analysis shows that the proportion of water is only 10 per cent, less than that of fresh meat, while their digestibility is precisely the same. 1 From an economic point of view, also, it must be regretted that there exists a prejudice against the use of horse- flesh as a substitute for ordinary meat. It is well flavoured — indeed, a Chateaubriand steak is said by connoisseurs to be best when made of horseflesh — and any toughness can be overcome by suitable cooking. In Paris the use of horseflesh for human food is increasing every year, and one can only hope the poorer classes in this country may ultimately take to it too. Indeed, it is stated to be already largely used in the manufacture of smoked meats. There is also a prejudice against the use as human food of the flesh of animals which have died of disease. This, again, can hardly be justified on grounds either of science or experience. The shepherds of Scotland have long used ' braxy ' mutton — i.e., the 1 Gautier, ' Frozen Meat as an Article of Diet ' (abstract in Edinburgh Medical Journal, 1897, N.S. , ii. 200). COST OF MEAT 7i flesh of sheep which have died of various diseases — and I am not aware that it has ever been known to produce any harmful results. A French observer 1 has recently put the matter to the test of experiment. He took the flesh of animals which had died of various diseases (including that of the mad dog !), cooked it in various ways, and gave it to people who were ignorant both of its nature and source. No bad effects followed its consumption. He concludes, fairly enough, that the use of diseased meat is harmless provided it be properly cooked, and that the overstrict inspection of slaughter- houses may do more harm by rendering meat dear, and therefore inaccessible to the poor, than it does good by preventing disease. It should be remembered that all small animals, such as rabbits, are necessarily expensive forms of meat both on account of their active metabolism, which implies that the greater part of the food they eat is lost in the form of heat, and also because of the relatively large bulk of their viscera. It is therefore impossible to hope that they can ever be a suitable form of animal food for the poorer classes. There remain to be dealt with some parts of animals, other than the flesh, which are sometimes used for foods, and which are usually classed together under the somewhat unsavoury title of offal. These comprise such articles as the kidneys, liver, sweetbreads, blood, heart, lungs, and other internal organs, and together make up about one-third of the total weight of the carcase. The general composition of these articles is shown in the following table : COMPOSITION OF OFFAL. Water. Nitrogenous Matter. 2 Fat. Carbo- hydrates. Ash. Kidney (ox) 767 i6'9 4-8 °'4 I - 2 (sheep) . 787 16 -8 3-2 1 '3 Liver (ox) . . 71-2 207 4'5 1 "5 1-6 (sheep 6l'2 23-1 90 5'° 17 Heart (ox) . . 62-6 i6'o 20 4 — I'O „ (sheep) 69-5 i7'o 12 '6 — 0-9 Lung (ox) . . 797 i6'i 3 2 — I'O (sheep) 75 V 20 - 2 2-8 — I '2 Sweetbreads 70-9 i6'8 I2'I — 1-6 Blood 8o-8 18-1 0'2 — 0-85 Tripe 74 "6 i6 - 4 8-5 — °"5 Tongue (ox) fresh . 638 17-1 i8'i — I'O ,, smoked and sal tec 357 24 \3 3i"6 — 8'5 Brain 80 -6 8 8 9 3 — 1 'i 1 Decroix, ' Recherches Experimentales sur la Viande de Cheval et sur les Viandes Insalubres ' ; Paris, 1885. 2 N x 6-25. 72 FOOD AND DIETETICS It will be observed that, from the chemical point of view, they are substances of considerable nutritive value, and as their price is also for the most part low, as compared with that of ordinary meat, they must be regarded as important sources of proteid in the diet. The liver and kidneys resemble one another in being compact, solid organs, containing but little connective tissue. This physical property renders them somewhat difficult of digestion, unless they have either been minced before cooking (as the liver is, for instance, in making a haggis), or are rather carefully chewed. Chemically, both consist chiefly of proteid along with a small amount of fat. The proteid which they contain is quite different from that oi ordinary meat, consisting as it does to a large extent of nucleo- proteid, which yields nuclein on digestion. Now, it has recently been proved that nuclein is an important source of uric acid, and for that reason it may be well for gouty persons to avoid the dietetic use of the articles under consideration. The heart resembles ordinary meat very closely as far as chemical composition is concerned, but differs from it in being of a denser structure, and therefore less digestible. For healthy persons, how- ever, it is an excellent and economical food, and might with advantage be made larger use of than at present it is. It seems natural to suppose that blood must be a very valuable food. ' The blood is the life,' and it would seem as if blood must represent in itself the essence of strength and energy. But it is not so ; and the misconception proceeds from a neglect of the fact that blood is not in itself the food of the tissues, but is merely the vehicle by means of which nourishment is carried from the intestines to the places where it is wanted in the body. One might as well expect a spoon to be of nutritive value because it conveys food from the plate to the mouth. Two French experimenters 1 found that blood when administered to dogs, even in the liberal measure of 2 pounds daily, did .not suffice to maintain the life of the animals for more than a month. This is due in part to the fact that blood is a dilute fluid, for, of every 100 parts of it, from 78 to 82 consist of water. Blood, in fact, from a chemical point of view, is not so much thicker than water after all. In the solids there is plenty of proteid, but the other nutritive constituents of food — fat and carbohydrates — are only represented in quite inappreciable amount. In addition to this, the red colouring matter (haemoglobin) which makes up the larger part of the proteid is a substance which is very far from being 1 Payen and Magendie. BLOOD AS FOOD 73 completely absorbed. 1 There are, thus, no chemical considerations which can outweigh the natural repugnance which most persons feel to the eating of blood ; and though it may be used without harm, if also without much benefit, in the form of black-puddings and such- like, there is no reason to advocate its habitual consumption, much less its employment in the feeding of the sick ; and this is true also of the use of blood as a source of iron. 2 The lungs, from the fact that the air which they contain enables them to float in water, are popularly spoken of as the ' lights.' They are sometimes eaten, but cannot be regarded as a really good form of food. Their chemical composition furnishes the reason. The lungs are largely composed of an elastic material belonging to the group of albuminoids, and only imperfectly capable of digestion, besides being useless as building matter in the body. Under the term sweetbread butchers include at least two distinct organs. The ' throat sweetbread ' is known to anatomists as the thymus gland ; the ' stomach sweetbread ' is the pancreas. The thymus of the calf is the one most frequently met with in the market. Both glands are cellular organs, held together by a loose and delicate connective tissue. From the nature of the latter they are easily dissolved in the stomach, and rank amongst the most digestible of animal foods, 9 ounces of sweetbread being completely disposed of by a healthy stomach in two and three-quarter hours, while a similar weight of beefsteak demands at least four and a half hours for its complete digestion. 3 The cells of these organs are chiefly composed of nucleo-proteid, and for that reason, as has already been pointed out in the case of the liver and kidney, sweet- breads may prove harmful in some cases of gout. Tripe is the name applied to the stomach and intestines of the ox after being cleaned and boiled. It contains a large amount of connective tissue, readily changed into gelatin on boiling, and so rendering the fibres easily digested. It contains fat in considerable amount, but not diffused through the muscular part. I am not acquainted with any experiments on its rate of digestion in the stomach, but in the intestine it has been found to be-as completely 1 See Gherardini, Rev. des Sciences Med., 1892, xxxix. 88; and Kobert, St. Petersburger Med. Wochenschrift, 1891, p. 439. Halliburton has investigated (Brit. Med. Journ., 1904, i. 823) the digestibility and absorption of haemoglobin. He found that it is to some extent at least digested by the pancreatic juice, and experiments on rats showed that under its administration the number of red cells in the blood rises, whilst the amount of iron in the tissues is increased. 2 See Starck, Deut. Med. Woch. , 1898, xxiv. 805. 8 Penzoldt, Deut. Archiv fur Klin. Med., 1893, li. 535. 74 FOOD AND DIETETICS absorbed as beef. 1 Unfortunately, the absence of extractives causes tripe to be rather deficient in flavour, but otherwise it must be regarded as a valuable and easily-digested food. The brain of animals is only occasionally eaten .as food. Brain consists largely of a fatty material containing cholesterin and lecithin, the latter being comparatively rich in phosphorus. In the stomach, owing to its soft consistency, brain is more rapidly digested than any other animal food, but, unfortunately, it is very imperfectly absorbed, 43 per cent, of it reappearing in the faeces {vide infra). In spite, therefore, of its easy digestion, it cannot be regarded as a valuable food for invalids, nor is it in any sense specially apt to ' make brains.' ' Some fancy,' says an ancient writer, 2 ' that Rabbits' Brains weaken the Memory, because this animal cannot for a moment after retain in mind the Foils laid for her and that she had just escaped ; but this conjecture, being grounded upon a weak Founda- tion, I shall not stop here and go about to confute it.' The idea that brain can in any way contribute to the nourishment of brain is grounded on an equally ' weak foundation.' The comparative absorption of some of the articles of which ws have been speaking, as found by experiment, is as follows : Voit 3 states that 100 parts of dry liver yield 5 parts of dry faeces. ., lung ., 8 ,, ,, thymus ,, 7 ,, ,, ,, brain „ 43 ,, ., Emil Bergeat 4 found the loss of nitrogen in the dog to be : In meat 2"i per cent. In thymus .. .. .. 32 „ In liver .. .. •• 3'3 » In lung .. .. .. 42 „ In brain .. .. ..139 „ The average composition of some potted meats is represented in the following table (from Konig) : . Water. Nitrogenous Matter. N-free Extractives. Fat. Ash. Salt. Foie gras Potted beef . . „ ham „ tongue . . 4604 3281 2557 4152 1459 I7-I7 1688 1846 267 336 046 3359 44' 6 3 5088 3285 311 203 678 671 022 572 598 1 Solomin, Arch, fur Hygiene, 1996, xxvii. 176. 2 Lemery, 1745. 8 Zeit. fur Biologic, 1889, xxv. 2-2. 4 Ibid., 1888, xxiv. 120. POTTED MEATS AND SAUSAGES 75 These substances require no special description. Sausages are preparations of very uncertain composition. It has been remarked of them with some truth that they are like life ; for you never know what is in them till you have been through them. In this country they are usually made of uncooked meat, but various vegetable substances, especially bread, are frequently added as well, and the vegetable matter is not infrequently disguised by the addition of colouring materials. Seasonings of various sorts also enter into their composition, and most of them contain a boron preservative. The following analyses by Allen 1 represent the composition of some typical kinds : COMPOSITION OF SAUSAGES. Variety. Price per lb. Water. Fat. Proteid. Gristle, etc. Starch. Ash. Pork . . gd. 5499 21 04 1228 067 I°5 352 ■ Cambridge ' pork gd. 5154 2972 9'45 072 220 347 Mutton .„ IS. 55-58 305I 1 89 311 390 2-50 German 8d. 4654 1787 1638 I 13 1500 4'47 Polony iod. 4557 3266 17 26 °54 230 280 As sources of proteid, they are certainly not more economical than ordinary meat. The use of bones as food will be dealt with in the next chapter. * ' Commercial Organic Analysis,' second edition, vol. iv., p. 280. .[ 76 1 CHAPTER V JELLIES— FISH The chemical basis of jellies is gelatin. Gelatin is derived from collagen, which is the chief constituent of connective ( tissues, and is converted into gelatin by boiling. All forms of connective tissue can be made to yield gelatin by suitable treatment. Glue is a crude form of the substance obtained from hide-clippings, and ordinary commercial gelatin is simply a purified form derived from the same source. The connective tissues of young animals are especially rich in gelatin-yielding material. Veal, for example, contains 4 to 5 per cent, of connective tissue, and is therefore a favourite basis for the making of strong soups. Calves' feet (free from bone) yield 25 per cent, of gelatin on boiling and 11*3 per cent, of fat, 1 and have long been known as abundant yielders of a pure jelly. The purest form of all, however, is isinglass, a substance obtained from the swim- bladder of fish, especially of the sturgeon. Chemically it is not really richer than ordinary gelatin, as is shown in the following com- parative analyses : 2 Ordinary Gelatin. Isinglass. Water .. .. .. 136 190 Albuminoid 842 77^4 Fat 01 16 Carbohydrate .... Ash .. .. .. .. 21 2 - o Full value per pound . . 1,570 Calories. 1,510 Calories. The chief physical peculiarity of gelatin is its capability of dis- solving in boiling water, and setting into a jelly on cooling. It is remarkable how weak a solution is capable of doing this. Even when as little as 1 per cent, is present the solution sets. The ordinary strength of which jellies are made is 1 ounce of gelatin to the quart, which is equivalent to a 2 per cent, solution, and from thi9 one can realize how little gelatin there really is in ordinary jellies. 1 Uffelmann, 'Ueber Sparstoffe und deren Verwendung in der Kost der gesun- den und Kranken,' Wiener Klinih, 1891, xvii., Heft 7. 2 Atwater, ' Chemical Composition of American Food Materials,' Bulletin 28, United States Department of Agriculture. GELATIN 77 I have found that 6 ounces (a large helping) of ordinary calf's- foot jelly contains if ounces of solid matter, of which less than ^ ounce is gelatin, the remainder being chiefly sugar. The digestion of gelatin in the stomach is a very easy process ; indeed, in this respect it is hardly surpassed by any other food. Uffelmann found that, in a boy with a gastric fistula, complete peptonisation took place within an hour, but he does not state how much jelly was administered. Gelatin has the advantage of fixing a good deal of acid in the process of digestion, and is thus of service in cases of hypersecre- tion of acid in the stomach. It seems also to belong to the ' pepto- genic* substances — i.e., those bodies which favour an abundant flow of gastric juice (see p. 417). In estimating the nutritive value of gelatin, 1 it is important to emphasise again that gelatin is not capable of building tissues, and is in no sense a true substitute for proteids. This has been attributed by Bunge to the fact that gelatin contains more oxygen and less carbon than proteids, and is thus, as it were, a stage on the way to their decomposition. As a source of heat and energy, it is equal to proteid or carbohydrate, 1 gramme yielding about 4-1 Calories. It is as a sparer of proteid, however, that gelatin is chiefly of importance in the food. It is the most powerful proteid-sparer known, being able to save from destruction half its weight of proteid, or twice as much as is spared by an equal quantity of carbo- hydrate ; but in estimating its value in this direction as an ordinary food, it must be remembered that even those who live on a' mainly animal diet do not consume more than one-tenth to one-eighth of their total nitrogen in the form of gelatin, and that probably not more than 25 to 30 grammes (about 1 ounce) of the latter substance can conveniently be taken in a day. This restricts its usefulness con- siderably, for even a quart of jelly would only be able to spare the proteid in i\ ounces of meat; and assuming that 25 grammes of gelatin were contained in the diet, this would only effect a saving of 35 grammes of meat (1 \ ounces) and 40 grammes of bread (1 \ ounces). An ordinary slice of a 4-pound loaf weighs i\ ounces. One can realize from this that the usefulness of gelatin as a proteid-sparer in fevers and diabetes is of limited range. As a pleasant addition to the diet of convalescence, however, jellies are of service, but their nutritive value depends mainly on the sugar which they contain, and , 1 See Murlin, Amer. Journ. of Physiol., 1907, xix. 285 ; and Mancini, II Poli- clinico, 1906, xiii., Sez Prat. 173 (abstract in Archiv f. V erdauungskranh . , 1907, Xiii. 326). 78 FOOD AND DIETETICS not on the gelatin. Their value in acid dyspepsia has already been mentioned. The cost of gelatin depends entirely on the source from which it is derived, and for ordinary purposes commercial gelatin (e.g., Cox's or Nelson's), is the most economical. It has been calculated that it costs sixteen times as much to prepare jelly from calves' feet as to use commercial gelatin for the purpose (Thudichum). Isinglass is also a costly source, a quart of jelly made of commercial gelatin costing about 6d., whereas if isinglass be used it will cost about is. gd., and it does not even seem to be altogether true that the latter goes further and sets better. The same is true of soups, for it is cheaper to add 7 or 10 grammes (\ to \ ounce) of gelatin to ordinary stock if one wants a strong soup than to get the gelatin from boiling up veal. Bones are only a cheap source of it in so far as they cannot be used for any other purpose. The composition of bones is about as follows : Water . . . . . . 5 to 50 per cent. Gelatin substance . . .. 151050 ,, Fat . . . . . . . . i to 20 , , Ash . . . . . . .. 20 to 70 , , When boiled in the usual way they yield from i£ to 7 per cent, of their weight, chiefly in the form of fat. When broken up and treated in a Papin's digester the yield is greater, 3 pounds yield- ing (according to Smith) as much nitrogen as can be got from 7 pounds of meat, and as much carbon as is yielded by 1 pound under similar treatment. In spite of this, Forster concluded from his experiments on the subject that it is cheaper to use commercial gelatin than to buy bones specially to produce it. Gelatin, there- fore, is merely a cheap addition to poor diets in so far as it can be obtained from many materials which would otherwise be wasted, and ordinary jellies can only be regarded as dear foods, for a shilling spent on the ' calf 's-foot jelly ' of the shops yields only 470 Calories of energy, and no building material at all. Fish. 1 1. Chemical Composition. — Proteid and fat are the chief nutritive constituents found in fish, just as they are in meat. According to 1 In preparing this section the writer has derived much help from the following publications : ' The Chemical Composition and Nutritive Values of Food Fishes and Aquatic Vertebrates,' by W. O. Atwater, Ph.D., Washington, 1891 (abstract from Report of United States Commissioner of Fish and Fisheries, 1888) ; and ' Fish as Food,' United States Department of Agriculture, Farmers' Bulletin 85," 1898, by C. F. Langworthy, Ph.D. COMPOSITION OF FISH 79 the relative proportions of these ingredients present, fish may be conveniently divided into the two groups of ' fat ' and ' lean,' or, more exactly, thus : (») Fish with more than 5 per cent, of fat. Examples: Eel (18 per cent.), salmon (12 per cent.), turbot (12 per cent.), herring (8 per cent.). (b) Fish with from 2 to 5 per cent, of fat. Examples : Halibut (2 up to even 10 per cent.), mackerel (2 up to 9 per cent), mullet (about 2J per cent.). (c) Fish with less than 2 per cent, of fat. Examples : Cod, haddock, whiting. The exact chemical composition of the commoner varieties of fish is shown in the following analyses by Miss Katherine Williams, 1 the results having reference to the fish as prepared for the table : ANALYSIS OF COOKED (BOILED) FISH AS SERVED AT TABLE. Fish. Herrings . . Salt herrings Sprats Sardines Salmon Trout Eels Mackerel Cod.. Salt cod Haddock Whiting Turbot Halibut Plaice Soles Lemon soles Oysters Smelts Red mullet Roach Gurnet Tunny Hake John Dory Brill Fart analyzed. Whole Flesh ' .. Whole . . Section Whole Heads removed Whole Section Whole ! ! Anterior and head Section Flesh Whole Shell contents Whole Flesh from section Section Whole . . Section , . Waste (Bones, etc.) 1 1 74 17-90 4-91 5 "99 8-23 n-66 10-51 15-99 6-13 35-10 21-50 31-20 6-84 2202 26-17 18-86 24-28 24'37 4630 784 2091 819 Gelatin. Water. 0-63 52-99 — 46-03 o-go 61-50 — 42-17 ° - 53 61 -06 o-55 67*12 1-09 53'29 0-25 65-21 °'43 63-78 0'33 67-68 o-8o 46-46 086 61-29 °'59 53-09 0-03 69-35 — 79-86 0-74 61-18 1-42 56-56 — 7771 038 65-20 241 5005 065 5652 065 3913 — 6349 026 7801 098 6082 019 5749 Nutrients. 34'54 53-97, 1970 52-92 32-02 24-10 33 96 24-03 19-79 25-86 17-64 16-35 15-12 2378 20-14 i6 - o6 I5-85 22-29 I5-56 23 26 1846 1392 3651 1389 1729 34' 13 1 Journal of Chemical Society, 1897, lxxi. 649. 80 FOOD AND DIETETICS ANALYSIS OF FLESH OF COOKED FISH. Reducing Solids n Dry Substance. Fish. Water in Substances Ash in Dry Flesh. in Dry Matter as Glucose. -** OU L/aLAllCCa N. Fat. Froteid. Herrings 60-54 5-56 II-II 25-25 67-07 Salt herrings 46-03 I7-59 1969 7-12 21-90 38-88 Sprats 7577 9-88 6-42 9-26 27-37 57-94 Sardines 44"35 " — 12-03 8-54 33 '49 55-44 Salmon 65 "32 14-89 4-94 10-70 29H3 56-65 Trout 73-58 4-68 6-6o 11-96 8-84 80 -oo Eels 61-08 891 2-II 7'36 44-68 42-88 Mackerel 73-13 I3-93 4-07 10-46 2573 62-32 Cod 76-32 6-67 3-3I 15-30 1 -15 91-55 Salt cod 72'35 7-14 I4'26 12-41 o-94 76-06 Haddock 72-37 I3-I5 3-28 13*11 1-29 79-57 Whiting 78-78 I7-54 1-92 13-28 1-86 79-55 Turbot 77-84 n-8i 2-41 1376 475 8471 Halibut .. 74-46 — 4-11 I3'32 15-81 79-67 Plaice 77-86 11-56 4-06 13-02 9-84 75-16 Soles 79-20 11-87 3'47 14-00 171 8671 Lemon soles . . 78-11 14-80 4-42 11-04 12-96 69-88 Oysters . . . . 7771 18-32 12-16 11-85 7'77 65-42 Smelts . . . . 8073 2-17 473 ii-6i 9-76 82-59 Red mullet 68-26 979 5 '43 "■59 24-52 66-26 Roach 7537 6-28 1-08 13-03 15-03 79 - H Gurnet 73*77 1477 3'53 14-24 i-8i 89-16 Tunny 63-49 5'52 io'55 30-68 66-o8 Hake 84-88 13-64 3 "9° 12-86 5-67 81-36 John Dory Brill 77-89 14-29 2 06 13-32 8-52 79-53 62-74 — 4-42 I5H9 1-62 93-95 In the following table the composition of some of the commoner varieties of fish in the fresh state is represented in a more con- venient form than in the above : COMPOSITION OF FISH. 1 Fuel Value Water. Proteid. Fat. Ash. per Found in Calories. Cod 82-6 I6'5 0-4 12 325 Eel 71-6 186 9-1 10 730 Flounder . . 84-2 142 o-6 i'3 290 Haddock . . 81-7 172 o-3 I'2 335 Halibut .. 75 '4 186 5-2 I'O 565 Herring . . 72'5 195 7-i i-5 660 Mackerel 73 '4 187 7 - i I'2 645 Mullet .. 74 '9 I9'5 4-6 12 555 Salmon . . 64-6 220 12-8 I '4 95o Smelt 79 '2 I76 1-8 17 405 Trout (river) 77 '8 ig-2 2 - I 12 445 ,, (salmon) . 70-8 I 7 -8 10-3 12 765 Turbot . . 71-4 I48 14-4 i-3 885 1 Compiled from analyses in the ' Chemical Composition of American Food Materials,' by Atwater and Bryant, Bull. No. 28 (revised edition), U.S. Depart- ment of Agriculture, Office of Experiment Stations, 1899, COMPOSITION OF FISH 81 To these may be added some recent analyses of preserved fish and of sardines in oil : PRESERVED FISH. Water. Nitrogenous Matter. Fat. Ash. Salt. Dried cod .. 16-16 81-54 0.74 1-56 Salt mackerel . . 44'45 I 9' I 7 22 '43 13-82 H'42 „ herring .. 46-23 18*90 16-89 i6 - 4i I4'47 Smoked herring 60/49 21-12 8-51 1-24 SARDINES IN OIL. 1 Source. Water. Fat. Proteid. Ash. Sicily .. ..' 50-16 i2 - 68 4-30 7*51 Tunis .. .. 50-36 13-07 4-07 7-85 Sardinia .. .. 4066 2375 3-83 8-98 Some points in these analyses are deserving of comment. The first thing to notice is the large amount of waste matter, in the form of skin, bones, etc., which fish contains. In fish, as sold, the waste may amount to fully 70 per cent., while even in fish as served at table it may be as high as 35 per cent. Another noteworthy point is the large amount of water in the flesh of the leaner varieties of fish — considerably more than in lean meat. Lastly, the relative proportions of the nitrogenous constituents are different from those in meat, fish containing more gelatin (about four to three in meat) and fewer extractives. Its greater richness in gelatin-yielding substance causes fish to lose more on boiling than meat does, and is one reason why boiling is by no means the best method of cooking fish(seep. 400). Its property in extractives is the cause of its lack of flavour as com- pared with meat, and makes a fish diet apt to prove monotonous. 2. Digestibility of Fish. — Artificial experiments outside the body on the digestibility of fish have yielded . discordant results. Popoff 2 arrives at the surprising conclusion that fat fish are more easily digested than lean ; while ' smoking ' actually increased the rate of digestion, prolonged cooking, on the other hand; rendering it slower. He gives the following table of the relative quantities digested in a given time : Meat, raw . . . . . . . . 100 , , boiled . . . . . . . . 83 , , smoked . . . . . . . . 71 Eel, raw . . . . . . . . 71 ,, boiled 68 ,, smoked .. .. .. .. 91 Sole, raw . . . . . . . . 66-8 ,, boiled .. .. .. .. 6o-6 ,, smoked .. .. .. .. 106-1 1 Journal of Chemical Society, vol. lxxii., 1897, part ii., p. 335. " Zeit, fur Physiolog. Chem., 1890, xiv. 524. 6 8a FOOD AND DIETETICS Chittenden and Cummins, 1 using a very similar method, got quite different results, for in their hands the fat fish proved less digestible than the lean, with the exception of mackerel, which was rather quickly dissolved. They found that the digestibility of fish in general was below that of beef, but several kinds were as easily digested as lamb or mutton. Cod, though containing very little fat,. proved to be one of the most indigestible of the fishes they examined. Penzoldt 2 employed a more natural method of experiment, fish being eaten in the usual way, and the time which elapsed before it had completely disappeared from the stomach noted. He found that 7 ounces of white fish were digested in two and a half to two and three-quarter hours, while a similar quantity of beef-steak required three and a quarter hours. Salt fish offered more resistance to the action of the stomach, 7 ounces of salt herring requiring four hours for its digestion. It must be admitted that the results of the last observer are more in harmony with those of everyday experience, which teaches that the lean fish are better borne by the stomach that the fat, and are apparently more easily digested than an equal quantity of meat. It is quite likely that fat interferes with natural digestion much more than with an imitation of the same process carried out in vitro : for not only does fat seem to arrest the natural secretion of gastric juice (p.419), but the fat found in fish seems also to be particularly apt to become rancid and affect the stomach injuriously in that way. That white fish should be more easily dissolved by the stomach than beef is only what one would expect from its shorter fibre. This is specially evident in such fish as the whiting, which on that account has been fancifully described, as ' the chicken of the sea,' and is frequently recommended, and probably with reason, to the dyspeptic and convalescent. Cod seems to be an exception, having a coarse fibre, and its comparative indigestibility, as found by Chittenden and Cummins, is by no means in contradiction with actual experi- ence (Pavy). The slow solution of salt fish is fully explained by the hardening of the fibres which salting produces. The absorption of fish, in the intestine takes place quite as well as that of meat, about 95 per cent, of the total solids, 97 per cent, of the proteid, and 90 per cent, of the fat entering the blood (Lang- worthy). In virtue of this, fish ranks amongst the most fully absorbed of foods. Nutritive Value of Fish.. — The value of fish as a source of energy depends entirely on the amount of fat which it contains. The fat 1 American Chemical Journal, 188485, vi. 318. 3 Deut. Archiv Jiir Klin. Med., 1893, li. 535. NUTRITIVE VALUE OF FISH 83 fish, such as salmon, are fully equal to moderately fat meat in this respect, while the lean fish, owing both to the absence of fat and the presence of more water, are of considerably lower nutritive value. It may be reckoned that i\ pounds of cod or other white fish are only equal in nutritive value to 1 pound of lean beef. 1 As a source of building material, fish is somewhat inferior to lean meat, owing to the smaller amount of proteid which it contains. This statement applies more strongly to lean fish than to the fatter varieties. Owing to this smaller proportion of proteid, and in part also, in all probability, to its lesser richness in extractives, fish seems to be a less stimulating food than meat, and on that account is sometimes recommended as a substitute for the latter in the dietary of epileptics. For the same reasons, white fish may sometimes be used with advantage instead of meat by sedentary persons, and in hot weather. Two special qualities are erroneously attributed to a fish diet by popular fancy. I refer to the beliefs (1) that fish is specially valuable as a ' brain food,' (2) that it possesses aphrodisiac qualities. The former of these opinions is grounded on the belief that fish is specially rich in phosphorus, and the way in which the fallacy became promulgated is of some interest. I have already referred to the dictum of Biichner, that without phosphorus thought is impossible (p. 41). The Swiss naturalist Agassiz, knowing this dictum, and being informed by the eminent chemist Dumas that fish contained much phosphorus, put two and two together, and concluded that fish would be specially good for the brain. But we have already seen that the aphorism of Biichner is not altogether true, and there is, further, no justification at all for the statement that fish is rich in phosphorus, and thus the belief that it is peculiarly adapted for the nourishment of the brain, being founded on a double fallacy, falls to the ground. The second belief, which attributes to a fish diet special stimu- lating powers on the genetic faculty, has been widely entertained, and is advocated at some length by Brillat-Savarin in his well-known book. There is, however, no sufficient evidence in favour of this opinion, and it is contradicted, as Pereira has pointed out, by the fact that maritime populations are not specially prolific. The impression that fish-eating produces a liability to certain diseases of the skin, and especially to leprosy, is founded on some- 1 Rosenfeld (' Der Nahrungswert des Fischfleisches,' Zentralb. f. inn. Med., 1906, xxvii. 169) concludes, as the result of metabolism experiments, that fish is a valuable source both of proteid and energy and can be recommended to the poor as a substitute for meat. 6—2 84 FOOD AND DIETETICS what more scientific data, and has been adopted by some eminent authorities, but the discussion of the subject cannot be undertaken here. One practical outcome of this belief has been the abolition of fish from th*3 dietary of the patients in the St. Louis Hospital for Skin Diseases in Paris. Economic Value of Fish. — In the case of fish, even more than in that of most foods, the market-price is no indication of the true economic value. I have already illustrated this fact by pointing out (p. 17) that although such fishes as haddock and sole are of practically the same nutritive value, yet the price of the latter may be four or five times that of the former. On the other hand, it by no means follows that none of the dearer varieties of fish is worth the money. Salmon, for example, contains nearly three times as much nutriment as an equal weight of cod, and thus a pound of the former at is. 6d. may not really be any dearer than a pound of cod at 6d. The amount of waste in fish is also of great importance from the economic point of view. We have seen that the inedible parts of fish as pur- chased may amount in some cases to as much as 70 per cent, of the whole, and allowance must be made for this in calculating the real cost. For this reason it may be worth while to pay a rather high price for canned or tinned fish, for in these preparations almost the whole of the material paid for is in an edible form. As a general rule, it may be said that the cheaper varieties of the fat fishes offer most nutriment for any given sum. Salted white fish probably rank next to these. An average herring contains about 15 grammes of edible proteid (nearly \ ounce) and from 5 to 10 grammes of fat, and it has been truly remarked by Dr. Smith 1 that the despised bloater ' offers the largest amount of nutriment for a given sum of any animal food,' and two salt herrings contain as much animal proteid as need enter into the daily dietary of an ordinary working man. The justice of these remarks is borne out by the following calcula- tions, taken from several made by Langworthy, 2 English prices being substituted for American : COMPARATIVE COSTS OF PROTEID AND ENERGY AS FURNISHED BY DIFFERENT KINDS OF FISH. Price per lb. Cost of Proteid per lb. Cost of 1,000 Calories of Energy. d. s. d. s. d. 3 11 2 oj Halibut . . 9 4 9 1 7 Salt cod . . 3i 1 10 11 Salt mackerel 5 2 10 5i Tinned salmon 6 2 34 6i Round of beef 7 3 2j 8 Milk . . 3d. per quart. 3 94 4* 1 • Foods,' p. no. a ' Fish . as Food,' p. 18. ECONOMIC VALUE OF FISH 85 The greater cheapness of the salt fish, and especially of those which are also fat, is at once manifest. Of the 'offal' of fish, the ovary, or roe, is alone commonly eaten. The roe of the sturgeon, when highly salted, constitutes caviare, the best forms of which come from Astrachan. Good caviare should be of a grayish colour — not black — and one should be able to make out the separate eggs in it quite easily. It is packed in vessels made of lime wood, as it is very apt to take up foreign flavours, and of these lime wood is destitute. The composition of caviare — and approximately of all fish-roe — is as follows (Langworthy) : Water .. .. .. .. .- 38*1 per cent. Proteid .. .. .. .. .. 30-0 Fat 197 „ Other non-nitrogenous matters .. 7 - 6 Mineral matter (including salt) .. 4 "6 Fuel value per lb. 1,530 Calories. The proteids contain a good deal of nuclein, the significance of which as an article of diet has already been mentioned (p. 72). Three ounces of raw salted caviare are digested in about two hours. The milt is the organ in male fish corresponding to the roe, and resembles the latter very closely in composition and nutritive value. The only patent food derived from fish with which I am acquainted is the preparation known as Marvis. 1 This consists of the flesh of white fish reduced to a dry powder, the characteristic flavour of the fresh fish being well retained. The substance' con- sists almost entirely of proteid, and has undoubtedly a high nutritive value. It keeps well, and may be conveniently employed for making soups, etc. The lobster, crab and other crustaceans, the molluscs, such as the oyster and mussel, and the turtle and frog amongst reptiles and amphibians, may conveniently be considered at this point. The lobster and crab both consist of two distinct parts : the flesh, which is contained in the claws and tail ; and the body, which is mainly made up of liver. The general composition of these parts is thus contrasted by Payen : Water Proteid Fat .. Flesh. Body. 766 84-3I 19-17 12-14 1 17 1 -14 1 Thompson, 23, College Hill, E.C. 86 FOOD AND DIETETICS Konig gives the composition of potted lobster as follows: Water .. .. .. .. .. 51-33 Nitrogenous matter .. .. .. 14 -87 Fat 24-86 Other non nitrogenous matter.. .. 4-04 Ash .. .. .. .. .. 4 -go Salt 0-38 That of tinned lobster is (Lang worthy) : Water 77-8 Proteid i8'i Fat 11 Carbohydrates . . . . . . . . o'6 Mineral mauer .. .. .. .. 2-4 The composition of the crab is practically the same. The flesh of the lobster and crab is rather indigestible, mainly on account of the density and coarseness of the fibres and the thickness of their walls. The use of vinegar helps to soften the fibres, besides neutralizing ammoniacal salts, which are apt to be present. The body of these animals is also apt to disagree, not only from the fat which the liver contains, but also, apparently, from the occasional development in it of irritant poisons. Three ounces of potted lobster require about two and a half hours for digestion in the stomach. The oyster is the most typical and popular of the molluscs. Chemically it contains within itself representatives of all three nutritive constituents of the food : AVERAGE COMPOSITION OF OYSTERS (Langworthy). (Exclusive of Liquid.) Water 88-3 Nitrogenous substances . . .. .. 6*1 Fat 1 '4 Carbohydrates .. . . _ .. .. 3-3 Salts . . . . . . . . . . 1 - 9 The proportion of solid nutriment, however, is not large, three dozen moderate-sized oysters having only from i\ up to 5J ounces of solids. It is probable, too, that the nitrogenous matter which they contain is not all in the form of proteid, but is partly present as other compounds of lower nutritive value. Glycogen is the form in which carbohydrate is present in oysters. It is contained in the liver. Its presence renders oysters an un- OYSTERS 87 suitable food in cases of diabetes in which a strict diet is being enforced. The oyster is rightly regarded as an easily-digested food — at least, if taken raw. Three medium-sized oysters are entirely disposed of by the stomach in one and three-quarters hours. Cooking renders them tough and less easily digested. The nutritive value of oysters is not high. A dozen Ostend oysters contain about 5 grammes of digestible proteid and i£ grammes of fat. It would take fourteen of them to contain as much nourish- ment as one egg, and 223 to equal a pound of beef (Stutzer). It is therefore not surprising to hear of enormous quantities of oysters being occasionally consumed at a sitting. Biillat-Savarin relates that he was acquainted with a man who used to eat a gross of them at a time, and follow that up by a heavy dinner ! They are an extravagant form of food, for a given quantity of proteid costs about three times as much in the form of oysters as it does if purchased as beef. In recent years oysters have to some extent fallen into disfavour, from the belief that they may be the means of conveying the in- fection of typhoid fever. The belief is not unwarranted, for if oysters are grown in estuaries they might easily enough become infected with typhoid germs derived from sewage, and it has been found by artificial inoculation that typhoid bacilli thus introduced are capable of surviving in the body of the oyster for several days. 1 The risk, however, can be avoided by keeping the oysters alive for a day or two in salt water which is frequently changed. This washes them out and destroys the bacilli. Cooking effects the same object with greater certainty, but at the cost of diminished digestibility. The ' greening ' of oysters is another subject which has recently attracted a good deal of attention. From their investigations into the cause of this phenomenon, Herdman and Boyce have concluded that there are several kinds of greening, some of which, such as that found in the green Marennes oysters and in those of several rivers on the Essex coast, are healthy ; while in others, such as some Falmouth oysters, the green colour is associated with the presence of an excess of copper. Others, again, such as some American varieties re-embedded on our coasts, have a pale green leucooytosis, and cannot be regarded as in a healthy state. 1 Herdman and Boyce, ' Lancashire Sea Fisheries.' Memoir I. : 'Oysters and Disease.' 88 FOOD AND DIETETICS Langworthy's investigations 1 led him to a somewhat different conclusion, for he regards ' greening ' as the result of the consump- tion by the oyster of certain forms of green algae, the colouring matter of which is soluble in the tissues and juices of the oyster, and apparently harmless. After being removed from the sea, oysters are sometimes 'floated' in brackish water, with the object of ' fattening' them. It has been found, however, that the apparent increase in plumpness of the oyster under this treatment is really due to the inhibition of moisture by osmosis, and that they actually lose from one-eighth to one-fifth of their nutritive value in the process. 2 The composition of mussels, clams, periwinkles, scallops and other molluscs is very similar to that of the oyster, and, like the latter, they cannot be regarded as foods of important nutritive value. They are also peculiarly liable to develop poisons which may produce serious, and even fatal, symptoms, and in susceptible persons their use is sometimes followed by irritation of the skin, usually taking the form of nettle-rash. The green turtle is almost the only reptile used for food in this country, and that chiefly in the form of soup. It is called green because its fat has a greenish colour, which, according to Sir Hans Sloane, 8 imparts a yellow tint to the sweat of those who partake largely of it. In preparing the soup, the dorsal and ventral shields are removed, scalded to remove the scales, and then boiled till the bones separate. The liquor forms the stock. The softer parts of the shield are then cut into oblong pieces, which constitute the so-called lumps of green ' fat ' — really a species of gelatin. Sun- dried turtle forms a soup of equal nutritive value, and at a consider- ably lower cost, while the basis of mock-turtle is the gelatinous substance in the scalp of the calf. From a strictly nutritive point of view, turtle soup is certainly not worth a tenth of the price paid for it. Frogs' legs are but rarely seen in this country, though common articles of diet on the Continent. They are derived from the large edible frog (Rana esculenta), and, though easily digested and of a delicate flavour, are not of high nutritive value. The average chemical composition of the different groups of foods studied in this chapter is represented in the following diagram, 1 'Fish as Food,' p. 17. 2 Ibid, p. 16. 8 See Pereira, ' On Food and Diet,' p. 273. THE TURTLE AND FROG 89 which also gives some idea of their relative nutritive values. It is constructed from the analyses published by Langworthy. FRESH FISH. MOLLUSCS. 0RUSTACEAN3 TURTLE * TERAPINE FROQ? LEQS. WASTE. d| WATER. [^] PROTEID f%^j FAT p^ ASH. Fig. 7. — Comparative Composition of Fish and their Allies I 9° ] CHAPTER VI SOUPS, BEEF-EXTRACTS, BEEF-JUICES, BEEF-TEA, AND BEEF-POWDERS When meat is cut up and placed in water for the purpose of making soup, there is dissolved out of it (i) a small proportion of its soluble proteids ; (2) a large part of its extractives and mineral matter ; (3) a small quantity of fat. If the water is now raised to the boiling-point, the proteid is coagulated and floats to the top as a brownish ' scum,' which is usually carefully skimmed off. At the same time the proportion of extractives and mineral matter in the solution is increased, and some of the connective tissue is dis- solved out in the form of gelatin. It will be evident from these considerations that a clear soup contains chiefly the flavouring constituents of the meat from which it is prepared. The amount of nutritive matter in it is very small, for a solution of gelatin of even 1 per cent, strength ' sets,' and very few soups contain as much as that. This estimate of the nutritive value of a clear soup is borne out by the following example : x 1 pound of beef and about \ pound of veal bones were boiled down in the usual way, and yielded 1 pint of strong soup. Analysis of this showed that it contained 95 per cent, of water and only 5 per cent, of solids, made up in almost equal proportions of fat, gelatin, and extractives, along with a small proportion of mineral matter. And yet this was a strong soup. Most clear soups contain only from 1 \ to i\ per cent, of solids. As an ordinary soup-plate holds, when full, about 7 ounces, a large helping of the above strong soup would only yield to the consumer about \ ounce of solid matter, and even of that only the gelatin and fat, say about | ounce, are really ' foods.' Seeing that it is chiefly the flavouring materials of the meat which 1 Atwater, ' Chemistry and Economy of Food,' p. 83. SOUPS 91 are removed in making soup, it is obvious that we cannot get a good soup and a well-flavoured dish of meat from the same piece of beef. You cannot both eat your cake and have it ; and although it is true that the meat, after the soup is made, has lost practically none of its nutritive qualities, yet its sapid and appetizing elements are gone. If, then, one wants to make soup nourishing, one must simply use it as a vehicle by means of which other food materials added to it can be conveyed into the stomach. Starchy materials are often added in this way, cornflour being, perhaps, one of the commonest. Barley is similarly used in barley broth. In potato soup, too, the soup is simply a vehicle for a considerable amount of potato starch. In other cases nitrogenous matter is added, such as grated cheese or macaroni (which contains a good deal of gluten), or the soup is thickened by the addition of one of the pulses, e.g., peas or lentils, the latter being amongst the most nutritious soups. Animal matters may be also be employed, as in the preparation of purees of chicken, fish, or game. The following analyses of two thick soups are taken from Konig : Water. Pea soup . . 88 '26 Potato soup 90-96 Even in these cases the nutritive value cannot be regarded as high, for half a slice of bread would contain as much solid matter as a full plateful of such a soup. It must not be supposed, however, that clear soups are of no dietetic value. It is not an error to begin dinner with soup. It has been found that it is just those very materials (extractives and gelatin) which a clear soup contains which are most calculated to promote a flow of gastric juice, and so to further the complete digestion of the solid food subsequently introduced into the stomach. As a French writer has said, soup should be to a dinner what the overture is to an opera or the porch is to a house. It is a good intro- duction. If, then, one gets the choice of ' clear ' or ' thick,' it may be well, if a solid meal is to follow, to select ' clear ' ; but if the soup itself is to be the piece de resistance, one should certainly choose ' thick.' For this reason, when soup is served out at penny dinners or soup- kitchens, it should always be made as thick as possible, preferably by the addition of one of the pulses, such as lentils or peas. In the case of an invalid, a ' strong soup ' may be a useful means of rousing Nitrogenous Matter. Fat. Other Nitrogen- free Substances. Cellu- lose. Mineral Matter. 3-38 l'37 0-93 1 '53 5'6o 4-87 070 0'26 I'I3 0-99 92 FOOD AND DIETETICS the appetite and stimulating the digestive powers of the stomach, but it cannot be regarded in itself as a serious contribution to his nutrition. Beef-Extracts. The valuable culinary qualities of an extract of meat were first recognised by Proust, but it was not until the matter was taken up by Baron Liebig that they became at all widely known. 1 The extract was first prepared on a commercial scale by the company authorized by Liebig in the year 1865. The factory was estab- lished in South America, as cattle can be obtained there much more cheaply than in Europe. The method of preparation is simple. The fresh meat is simply chopped up, heated under pressure with a little water, the extract filtered and evaporated in vacuo and in the open. The product is the brown, sticky material with which everyone is familiar. A good sample should have a rather golden-brown colour. If too dark, it has probably been burnt, and it should have a strong and agreeable ' meaty ' odour. Liebig calculated that 34 pounds of pure beef should yield 1 pound of the extract, and that this should make 70 pints of beef-tea, every pint therefore corresponding to £ pound of beef. He fixed the com- position of the article to be sold thus : Moisture may vary from . . .. .. 16 to 2 1 per cent. Mineral matter may vary from .. .. 18 ,, 22 ,, Extractives may vary from . . . . . . 56 „ 60 „ Liebig expressly forbade the sale of any extract containing gelatin. The latter substance is so cheap, he said, that it would tempt people to add it as an adulteration, and would also prevent the extract from keeping. It would then sink to the level of * tablets of consomm6,' which he regarded as ' a kind of coloured glue.' He likewise discountenanced the addition of any salt. It will be observed that into the composition of Liebig's extract as fixed by its inventor no proteids or albuminoids enter. A vast number of analyses, however, have been made of it in more recent times, some of which have credited it with containing these valuable nutritive constituents in considerable amount. Amongst the most striking of these is an analysis by Kemmerich, 2 which yielded the following results : 1 See Thudichum, ' Origin, Nature, and Uses of Liebig's Extract,' London, 1869. 2 Zeii.furPhysiolog, Chemie, 1894, xviii. 409. BEEF-EXTRACTS 03 Composition of Lung's Extract according to Kemmerich. Water 18 per cent. Proteids . . ) Gelatin j 3 ° Extractives . . . . . . . . . . 25 ,, Mineral matter 20 „ Ether extract, etc. . . . . . . . . . . 7 „ This was certainly a very startling result, but it was not allowed to go long unchallenged, for Konig and Bomer 1 have submitted the above analysis to a searching criticism, and have shown, and I think conclusively, that it was arrived at by faulty methods. They point out that one could not a priori expect Liebig's extract to contain much gelatin, for heat is only employed in its preparation to a small extent, and, further, solutions of it do not gelatinize. They show that it contains only about 7 per cent, of albumoses, and perhaps traces of peptone, but certainly not more than 1 per cent, of gelatin, and distribute the amount of nitrogen which it contains thus: Total nitrogen . . . . 9-28 per cent. Nitrogen in the form of soluble albumin . . Trace Albumoses .. .. .. .. .. .. 0-96 per cent. Peptone .. .. .. Nil to a trace. Meat bases .. .. .. 6-8i per cent. Ammonia compounds 0-47 „ Other nitrogen compounds 0-83 „ More recent analyses of Liebig's extract ('Lemco') by the Lancet 2 gives the following as its range of composition : Moisture .. .. .. From 1712 per cent, to 21-50 per cent. Mineral salts . . .. .. „ 1835 ,, 2630 ,, Organic matter .. .. .. 55'34 1. 62-43 „ n »» Total nitrogen , 9-48 ,, 11-62 „ Albumose , 8-52 „ 14-26 ,, Peptone , 3-34 „ 560 „ Total proteids .. .. ,, 14-12 „ i9'34 » Creatin and creatinin .. „ 9-00 „ 1250 ,, Insoluble matter .. .. ,, 0-25 „ 088 ,, Sodium chloride .. .. ,, 268 ,, 569 ,, Phosphoric acid (P 2 O s ) .. ,, 306 ,, 670 „ Although, therefore, small amounts of albumose and peptone are present, it is upon the extractives that the uses and value of the extract must chiefly depend, and for that reason we must now look a little more closely at their chemical and physiological properties. 1 Zeit. fur Analyt. Chemie, 1895, xxxiv. 548. 2 Report of Special Commission upon the Origin, Manufacture, and Uses of Extract of Meat, L Prausnitz, Zeit.f. Biologic, 1889, xxv. 533. 4 Raudnitz, Zeit.f. Physiol. Chem., 1890, xiv. 1. s Vassilieff, quoted by Cautley, ' The Feeding of Infants,' 1897, P- 2I 4- 126 FOOD AND DIETETICS absorbed than the same ingredients after boiling ; but this conclusion is disputed by a third. 1 It has further been found in the case of infants and calves that ' sterilized milk ' which has been kept at or above the boiling-point for more than an hour is absorbed quite as well as milk which has merely been boiled in the usual way. 2 Taking the whole of the evidence, the conclusion seems to be justified, that just as boiling does not appreciably diminish the digestibility of milk in the stomach, so it does not to any important extent interfere with its absorption in the intestine. One need have no fear, therefore, that the great advantages of boiling are purchased at the cost of any noteworthy diminution of digestibility or absorption. 3 Two other points relating to the behaviour of milk in the intestine call for mention. The first is that milk seems to be absorbed with less expenditure of energy — that is to say, with less wear and tear upon the part of the intestine, than any other food. 4 This no doubt explains in part the great value of milk-diet in many intestinal diseases. The other point is that milk seems to exercise a restraining influence upon putrefactive processes in the intestine. The explana- tion of this, whether it is to be attributed to the casein or to the influence of acids produced from the milk-sugar, is still disputed, but of the fact there appears to be no doubt. There is reason to believe that much of the value of milk diet and milk ' cures ' in many cases is due to the diminished absorption of putrefactive products from the intestine which these bring about. 8 4. Nutritive Value of Milk. It is frequently said that milk is a perfect food. Now, this is a high claim, and can only be justified in the case of any food if it fulfils all of the following conditions : 1 . It must contain all the nutritive constituents required by the body : proteids, fats, carbohydrates, mineral matter and water. 2. It must contain these in their proper relative proportions. 3. It must contain the total amount of nourishment required daily in a moderate compass. 1 Gaschibowsky, Maly's Jahres-Bcricht Thier-Chemie, 1894, xxiv. 502. 2 See Bendix, Jahrb. f. Kinderheilk., 1894, xxxviii. 393 ; Cautley, op. eft., p. 215 ; and Weber, Bull, de la Soc. Med. Prat, de Paris, 1892, p. 77. 3 Recent experiments on young rats (Journ. of Hygiene, 1909, ix. 233) showed m diminutionin the nutritive value of milk when boiled, or even when evaporated and dried. 1 Pawlow, ' Die Arbeit der Verdauungsdriisen,' p. 189. 6 The alterations in the urine of patients on exclusively milk diet pointed out by Weir Mitchell (' Fat and Blood,' p. 114) are also to be explained by a diminution, of intestinal putrefaction. NUTRITIVE VALUE OF MILK 127 4. The nutritive elements must be capable of easy absorption, and yet leave a certain bulk of unabsorbed matter to act as intestinal ballast. ■ 5. It must be obtainable at a moderate cost. On examining the claims of milk to be regarded as a perfect food, one finds that it only conforms to the first of the conditions above laid down. It does indeed contain representatives of all the nutritive con- stituents required by the body, but it does not contain them in proper relative proportion. Relatively it is too rich in proteid and fat, and too poor in carbohydrate, to be a perfect food. In order to obtain the requisite 3,000 Calories of energy daily, one would require to con- sume about 8 pints of milk, and that would contain about 140 grammes of proteid, which is considerably more than is necessary. An excess of proteid and fat is essential in the case of infants, where the body substance is being added to by growth and where a large supply of fuel is needed, but it is not necessary for adults. Milk, in fact, is a food for babes, not for men. Further, milk is much too bulky to be a perfect food. For the complete nutrition of a healthy man doing a moderate amount of muscular work about 8 pints of milk would be required daily. CII___^ ^___^ LOSS. That means that a tumblerful L £-r-= — ^rz : '■ 0-58 Grins of milk must be swallowed every hour of the working day. This is an inconveniently large quantity, and necessitates the burdening of the system with a considerable surplus of water. In the matter of ballast, also, milk is deficient. It is true that it is by no means com- pletely absorbed, but the residue is not bulky enough to supply a sufficient stimulus to peristalsis, and it is well known to be a constipating food. Lastly, milk is too expensive to be a perfect food. To live on it alone would cost about is. 6d. a day. An ordinary mixed diet can be obtained for less than a shilling. 0-49 Grins, MAT p r.-.ggg^^ Fig. 8. — Actual Composition of a Tumblerful of Ordinary Milk, and Percentage of Loss from Non-ab- sorption. 128 FOOD AND DIETETICS We conclude, then, that milk is by no means a perfect food. On the other hand, it is admirably fitted to supplement the deficiencies of other articles of diet. It is one of the cheapest sources of animal proteid. Eight pennyworths of whole milk yield as much proteid as ten pennyworths of beef. But milk has the advantage over beef of containing a considerable amount of carbohydrate in addition to its proteid and fat, with the result that a quart of good milk is nearly equal in nutritive value to a pound of beef-steak. Skim milk is an even cheaper source from which to supplement any lack of proteid in the diet, for it. supplies that constituent in a cheaper form than any other animal food except salt fish. Its great value in the dietary of persons to whom economy is of importance cannot be overestimated. It is in carbohydrate that milk is specially deficient. Hence it should be used chiefly in conjunction with other foods rich in that ingredient. Such a food is bread. An interesting practical illustration of the great nutritive and economic value of a combina- tion of skim milk and bread is furnished by the following comparison of a lunch composed solely of these ingredients with an ordinary lunch, such as might be supplied at a restaurant. 1 Lunch op Skim Milk and Bread. Restaurant Lunch. In- gredients. Amount. Cost. Fuel Value in Calories. In- gredients. Amount. Cost. Fuel Value in Calories. Bread .. Skim milk 10 OZ. I pint iid. id. 755 170 Soup . . Beef . . Potatoes Turnips Bread . . Butter Coffee : Milk Sugar 8oz. 2 ,, 2 ,, I .. 4 .. *.. I ir 75 275 100 15 300 100 20 . 55. Totals zd. 925 Totals 8d. 940 It will be observed that bread and milk furnished at a cost of 2d. almost as many Calories («'.«., heat and energy) as were obtained from the restaurant lunch at four times that price. The claims of skim milk to be regarded as a valuable source of food are thus fully justified, and should be carefully considered by all who are responsible for drawing up an ample and economical dietary for large numbers of persons, such, for example, as the inmates of public institutions. Unfortunately, the prevailing tendency is to regard milk as a 1 From ' Milk as Food ' (original edition), United States Department of Agri- culture, Farmers' Bulletin, 74. NUTRITIVE VALUE OF MILK 129 beverage rather than as a food. This is a great mistake, in proof of which one cannot do better than quote an extract from the valuable pamphlet on ' The Use of Milk as Food ' issued by the United States Department of Agriculture, to which reference has already been fre- quently made. The following extract states succinctly the advantages which are obtained from the liberal use of milk in a dietary : 'A very interesting experiment was recently made at the University of Maine, in co-operation with this department, in which the effect of a limited and an unlimited amount of milk was tried at the University boarding-house or " commons." From these studies the following conclusions were drawn : (1) The dietaries in which milk was more abundantly supplied were somewhat less costly than the others, and at the same time were fully as acceptable; (2) the in- creased consumption of milk had the effect of materially increasing the proportion of proteid in the diet ; (3) the milk actually supplied the place of other food materials, and did not, as many suppose, simply furnish an additional amount of food without diminishing the quantity of other materials ; (4) the results indicate that milk should not be regarded as a luxury, but as an economical article of diet which families of moderate income may freely purchase as a probable means of improving the character of the diet and of cheapening the cost of the supply of animal foods.' As an article of diet in disease milk occupies a unique position. No single food, it may safely be said, is of so much value. The drawbacks to its exclusive use in health, which it was one's duty to point out above, are now of no account, or are even converted into advantages. The use of milk in the dietary of different diseases will be considered in detail in a subsequent chapter, but some of its general advantages may be mentioned in this place. Being in a fluid form, it is easily swallowed. This is a great gain in the case of exhausted patients. For the same reason, the quantity given can be very simply regulated and measured. Its fluid form also enables it to be used as a substitute for other beverages, and a glass of milk with each meal is one of the simplest prescriptions for increasing the amount of nourishment a patient is taking. It is often recommended to people who require to be ' fed up.' The amount of water which it contains causes milk to be a means of quenching thirst as well as of supplying food, and makes it grateful to feverish patients. In virtue of the same property it can act as a diuretic, a function which is of great help in the treatment of some forms of heart disease with oedema, in cases of renal disease, and in all inflammatory affections of the urinary passages. 9 130 FOOD AND DIETETICS The bulkiness which its richness in water entails is no serious drawback in most cases of illness. A patient who is at rest and warm in bed requires much less nourishment than an active man, and will often gain weight on 3 or 4 pints of milk a day, although more than twice that quantity is requisite for the needs of health. 1 In addition to this, there is reason to believe that concentrated foods are not well borne in cases of severe disease, and that a moderate degree of dilution is an advantage rather than otherwise. The peculiar behaviour of milk in the stomach and intestine, the fact that it is digested with little secretory effort and absorbed with but a moderate expenditure of energy, and that its presence tends to restrain the development of intestinal putrefaction, have been already referred to, and mark milk out as a food of special value in gastro- intestinal disorders. To these advantages should be added the facts already mentioned, that, though rich in proteid, milk is devoid of such ' stimulating ' substances as are found in meat, and that its use is attended by a diminution in the excretion of uric acid. It is probably to a combination of these advantages that ' milk diet ' and ' milk cures ' owe the benefits obtained from their use. 2 From an early age milk was regarded as a sovereign remedy in many diseases. By Hippocrates, Celsus, and Galen it was recom- mended in phthisis, and especially in gout. Amongst medieval writers Van Swieten and Hoffmann also recognised its great virtues, whilst its most strenuous advocate in modern times has been Dr. Karell, late physician to the Czar of Russia. 3 Donkin also did much to make its virtues known, while in later years it has attained prominence as an important part of the ' Weir-Mitchell treatment.' Karell recommends a trial of the milk cure in dropsies, asthma, neuralgias of intestinal origin, cases of ' malnutrition,' and some diseases of the liver. Its use in diabetes, obesity, and some forms of val vular heart disease will be considered later. The directions given by those who have had most experience of its use are that the milk should be skimmed, and should be given quite fresh, not boiled. 'A temperature of 212° F., I feel assured,' 1 See Horton Smith, Journ. of Physiol., 1891, xii. 42, and Prausnitz, Zeit. f. Biologic, 1889, xxv. 533 ; also Weir Mitchell, 'Fat and Blood,' chap. viii. 2 It is now believed that some, at least, of the advantages of an exclusive milk diet in disease are to be attributed to a limitation of the intake of salt which such a diet entails. In other words, it is a ' de-chlorinatmg ' diet. (See ' Salt-Free Diet,' p. 556 ) 3 ' On the Milk Cure,' Edin. Med, Journ., 1866, xii. 97. An interesting historical resume of the therapeutic uses of milk will be found in Donkin's ' Diabetes and Bright's Disease,' 1871, chap. i. MILK CURES 131 says Donkin, ' either seriously impairs or altogether destroys its therapeutic energy, possibly by altering the molecular constitution of the casein or by destroying some vital property with which it is endowed.' At first not more than 2 to 6 ounces should be given, at regular intervals of three or four hours, none being given at 4 a.m. The milk should be sipped, not swallowed at a draught, and may be given either warm or cold as preferred. By the third day the quantity at each feed may be increased to half a pint, so that in all 3 pints are consumed. By the end of a week the total may have risen to 6 pints per day, but one should not attempt to go much above this. The ' cure ' should last five or six weeks. Amongst the ' normal ' symptoms exhibited by a patient on a purely milk diet are a certain amount of drowsiness and the passage of a large quantity of urine of a pale greenish colour, which gives no brownish-red ring on the addition of nitric acid. The tongue is covered with a white fur, and there is often a sweetish taste in the mouth. A moderate degree of constipation is a good sign, orange- coloured stools being passed at intervals of two or three days. If this symptom becomes too pronounced, a little coffee or caramel may be added to the morning's milk, or a little stewed fruit may be taken once a day. Diarrhoea is due to the use of a too rich milk. The objections, frequently of a fanciful nature, which are often urged by the patient at the beginning of such a regimen must be overcome by firmness and tact, while in some cases the addition of a little tea, coffee, caramel, or salt may make the milk more endur- able. Q~ rT ^M [ 132] CHAPTER VIII FOODS DERIVED FROM MILK Whey — Cream — Butter — Butter-milk — Koumiss and Kephir — Casein preparations. Whey. We have already learnt that whey is the fluid which exudes from clotted milk. It is best prepared by adding to 30 ounces of milk heated to 104 F. two teaspoonfuls of rennet, and setting aside in a warm place till clotting has occurred. The clot must then be broken up very thoroughly by stirring, and the whole strained through muslin. About 22 ounces of whey should be obtained with (approximately) the following composition : Water .. .. 93-64 per cent. Proteid 0-82 „ Fat 0*24 „ Sugar 4-65 „ Mineral matter . . . . . . . . . . C65 „ Whey can also be made by precipitating the casein by means of an acid — e.g., a sour wine. It is in this fashion that white wine whey is prepared. Alum whey is a similar product. Whey, as its composition indicates, is a fluid of but small nutritive value. It hardly ever enters into an ordinary diet, but is often an aid in the feeding of infants. 1 It has slight laxative properties, and should be avoided when there is any tendency to diarrhoea. The so-called whey cure is a means of treatment sometimes re- sorted to in cases of dyspepsia, especially when occurring in gross feeders (' abdominal plethora '). Its range of usefulness is much the same as that of the grape cure, and, as in it, large allowance must be made for the favourable influence of the open air and exercise which form a part of the regimen. The quantity of whey consumed is at first limited to a tumblerful night and morning, but the amount is gradually increased until a maximum is reached of ten tumblerfuls per day. The only other foods allowed are vegetables and fruits. 1 See Ashby, Eiin. Msd.Journ., 1899, N.S., v. 389. CREAM 133 It should be added that whey is sometimes a useful addition to the diet in cases of nephritis accompanied by constipation and in cases of uric acid gravel. It may also be substituted for milk with advantage when jaundice is present, and in cases of typhoid fever when curds are passed in the stools. Cream. Cream consists essentially of the fat of milk. It would be a mistake, however, to suppose that it consists of that alone. It contains in addition proteid and sugar in nearly as high proportion as milk itself. 1 The main difference, indeed, between milk and cream is that in the latter some of the water of the milk has been replaced by fat. The exact amount of fat in cream varies very much, the differences depending to a large extent on the method by which the cream has been separated. In cream produced by a centrifuge the proportion of fat may amount to 65 per cent., while in ordinary cream, obtained by skimming, it may be merely 20 per cent, or less. The average amount of fat in specimens of centrifugal cream examined by Droop Richmond in 1894 was 4^"9 P er cent. In 716 samples obtained from the London market in 1889 Vieth found an average of 45-! per cent, for single and 53^ for double cream. 2 On an average, perhaps, one may say that a sample of good cream should contain 41 per cent, of fat. There is thus as much, or even greater, need for fixing a legal standard for cream as there is for milk. Some authorities 3 would fix the standard at 45 per cent, of fat ; others would make it illegal to sell as cream anything which contains less than 25 per cent. 4 The well-known Devonshire or clotted cream is a special variety prepared by heating the milk in deep pans, which causes a rapid and very complete separation of the fat. The proportion of fat in such cream is not far short of 60 per cent., as is shown in the following analyses : 6 Water. Proteid and p ^ Sugar. 1. 3248 .. 860 .. 5821 .. 071 2. 3554 .. 680 .. 5709 .. 057 Devonshire cream contains only about half as much sugar as ordinary cream. For this reason it is peculiarly suited to be a source of fat in the dietary of diabetics. 1 Cream contains about 2-5 per cent, of proteid, 4-5 per cent, of sugar, and o - 5 per cent, of mineral matter. 2 Milchzietung, 1889, p. 142. 8 Pearmain and Moor. 4 Wynter Blyth. " Droop Richmond, Analyst, 1896, p. 88. 134 FOOD AND DIETETICS In a physiological sense cream is chiefly to be regarded as a fuel food. It has been calculated that a pint of it should yield about 1,425 Calories, or about as much as i£ pounds of bread or ij dozen bananas or 4J pounds of potatoes. In sick-room feeding it is an important aid in getting fat into the diet, for it is very easily digested. Good cream (45 per cent.) contains as much fat as a similar quantity of most cod-liver oil emulsions, and is usually much better borne. A gill of it per day is a not uncommon prescription. Cream, however, is by no means an economical source of fat. One and a half pints of it do not contain more fat than one pound of butter, and cost about three times as much. Cream, therefore, is to be regarded as a luxury. Butter. Butter is produced from cream by churning. This causes all the fat globules in the cream to run together into a solid mass, while the fluid part, containing almost all the sugar and most of the casein, remains in the form of butter-milk. The flavour and aroma of butter are due to the growth of organisms in the cream during ripening; butter prepared from pasteurized cream is devoid of flavour. 1 The trace of casein which remains in the butter is of importance, for the decomposition which it undergoes on keeping is apt to make the butter turn rancid. The presence of water in the butter facilitates this change. Butter can be made to keep indefinitely by melting it down, and then boiling it till all the water is driven off, as evidenced by the cessation of violent ebullition. The melted butter is then strained through muslin to remove the casein, poured into a bottle, and allowed to cool. If corked up, it will keep almost indefinitely, and when wanted a portion can be removed with a cheese scoop, or the butter can be melted and poured out by standing the bottle in hot water for a short time. This method is largely used in India for the preservation of butter (ghee), and also on the Continent. The exact amount of fat in butter varies within fairly wide limits, but averages about 82 per cent., or twice as much as the amount in cream. An ounce of butter, therefore, may be reckoned as the equivalent of \ ounce of pure fat. In addition butter contains 12 to 15 per cent, of water and about 2 per cent, of non-fatty organic matter, chiefly casein and milk-sugar. 1 See Ninth Annual Report of Storrs Agricultural Experiment Station, 1896. BUTTER AND MARGARINE 135 The most striking chemical characteristic of butter fat is its rich- ness in those fatty acids (butyric, caproic, capric, and caprylic) which are soluble in water. Of these it contains about 7 per cent. Butyric acid, indeed, may be said to be the hall-mark of butter, from which it derives its name. Of the insoluble fatty acids present oleic is the most abundant. Butter fat contains 40 per cent of olein. This means that it has a low melting-point (31-34° C), and that in its turn implies, for reasons we have already discussed, that it is easily digested and absorbed. As a matter of fact, butter is the most easily digested of fatty foods. The fat of the human body has also a large proportion of olein, and melts at an even lower temperature than butter (25° C). The fact that butter fat approximates so closely to it in its proportion of olein may perhaps help to explain the great value of butter as a food. The ease with which butter is digested renders it of great value as a source of fat in the diet of sickness. In phthisis, diabetes, and many forms of dyspepsia, patients can take J pound of it a day without difficulty, and with great advantage to their nutrition. Cooked butter, on the other hand, is much more apt to disagree, probably owing to the liberation of fatty acids in it by the heat employed in cooking. The absorption of butter in the intestine is very complete. Even when \ pound of it is taken per day, less than -5 per cent, is wasted. This is a more favourable result than would be obtained with any other form of fat, and should teach us that it may be well to give butter a fair trial before having recourse to cod-liver oil or other medicinal fatty preparations. Margarine. From what has been said as to the chemical composition of butter, it will be apparent that if part of the more solid constituents (stearin and palmitin) could be removed from ordinary animal fats, leaving chiefly olein, the substance left would resemble butter very closely. As a matter of fact, that can be done, and the product is known as margarine. 1 Margarine owes its origin to the ingenuity of the French chemist Meges-Mouries, and was first manufactured under his direction for use in the French Navy in the year 1870. It is made by melting down and clarifying various animal fats, that of the ox being now 1 Margarine derives its name from ' margarin,' a supposed fat, really a mixture of palmitin and stearin. It is also known as 'oleomargarine,' 'butterine,' and ■ Dutch butter,' but by the Act of 1887 all butter substitutes are now described as ' margarine.' In the United States the term ' oleomargarine ' is employed. 136 FOOD AND DIETETICS chiefly employed. The melted fat is allowed to cool slowly, with the result that the stearin solidifies first. The more fluid com- ponents (palmitin and olein) are removed by pressure and churned up with a little milk to give them the flavour of butter. The product is then tinted with some vegetable dye, and is ready for use. It has the following composition : x Water . . . . .. .. 9 -3 per cent. Proteid .. .. .. .. 1-3 „ Fat 827 Ash .. .. .. .. .. 67 „ It will be observed that the proportion of fat is exactly the same as in an average specimen of butter, and the only point in which the two differ is that butter has a much higher proportion of the soluble and volatile fatty acids. 2 There is no reason to believe that this is in any way to the disadvantage of margarine as a food. The fat of our bodies contains no soluble fatty acids, and human milk fat is almost destitute of them too. Indeed, one might almost regard the absence of butyrin as a point in favour of margarine, for when butter becomes at all rancid butyric acid is liberated from the butyrin, and butyric acid is an exceedingly irritating substance. ■ The comparative absence of casein in margarine is also a good point, for casein, as we have seen, tends to promote the decomposition of butter, and its absence should help margarine to keep better. So much from the chemical side. From a physiological point of view margarine is equally deserving of recommendation. It is absorbed almost as completely as butter, the difference being only about 2 per cent. In other words, 102 pounds of margarine are equal in nutritive value to 100 pounds of butter. 3 Whatever may once have been the case, margarine is now made only from pure animal fats, and the processes to which it is subjected in manufacture insure its further purification. As the flavour of the best variety is equal to that of an average specimen of butter, and as it has the advantage of being very much cheaper, there is every reason to wish that the prejudice against it, which is still rather widespread, should quickly disappear, and that it should be welcomed as an admirable and cheap substitute for a rather expensive, but necessary, food. Before leaving the subject of butter, one may consider for a moment what is its relative value as an addition to the diet when compared with jam. This subject is one of very considerable interest 1 Average of thirty-five analyses by Atwater. a Butter has 7£ per cent, of butyrin ; margarine has only o"25 per cent, * See Rottger, ' Lehrbuch der Nahrungsmittel Chemie,' p. 182. BUTTER VERSUS JAM 137 to the poorer sections of the community, and involves really two questions: (1) To what extent can sugar (which is the most important ingredient of jam) replace fat in the diet ? and, (2) Is the replacement effected at a saving of expense ? The first of these questions has been dealt with to some extent in a previous chapter (p. 26). It need only . be repeated here that 1 part of fat is equal to i\ parts of sugar in fuel value, and that sugar and fat can replace one another to a considerable extent provided these proportions be observed. It would seem, however, although one cannot give any definite scientific reason why it should be so, that fat cannot be wholly replaced in the diet by sugar or other carbohydrate without detriment to health, and that this is especially true of young children. As regards the second question, it can easily be shown that, even were the substitution of jam for butter justifiable on physiological grounds, it cannot be effected with any real economy. It would require about 3 pounds of jam to be equal in fuel value to 1 pound of butter, and at current prices the former would cost about is. 3d., the latter, say, is. 2d., a difference slightly in favour of butter. 1 In order, therefore, to effect any saving by substituting jam for butter, one would require to eat less of the former than would really replace the butter, the result of which would be that one's nutrition would suffer. The money saved would be balanced by vigour lost. The subject is further complicated by the fact that it takes a greater weight of jam than of butter to cover any given piece of bread. I have found that an ordinary slice of bread, when spread the usual thickness, is covered by 40 grammes (if ounces) of jam or by 8 grammes (about | ounce) of butter. In other words, as actually used, it takes 5 pounds of jam to go as far as 1 pound of butter ; and although it is true that the number of Calories yielded by the former quantity is about one-third greater than that obtained from the latter, yet the cost is also considerably greater. Notwithstanding, then, that the cost of butter and jam is, from a nutritive point of view, almost equal, the housewife will always find the latter more costly than the former, simply because more of it is used. It is true that the extra quantity of jam conveys some extra 1 This calculation is based on the assumption (1) that 1 part of fat is equal in fuel value to 2J parts of carbohydrate, and (2) that ordinary jam contains about 60 per cent, of sugar (see a paper by Aitchison Robertson, Scottish Medical and Surgical Journ., 1898, iii. 31) and a good sample of butter 82 per cent, of fat. Some physiologists (e.g., C. Voit) assume a different ratio between fat and carbohydrate, namely, that 100 parts of the former are equivalent to 175 of the latter. On this basis, 2£ pounds of jam would be equal in value to 1 pound of butter, and the former would cost ijd. less than the latter. 138 FOOD AND DIETETICS carbohydrate into the body, but that result could be achieved at less cost by the consumption of a larger amount of bread. At the same time, it must be admitted that one pays dearly for the pleasant flavour of butter. ' As far as nourishment is concerned, a pound of dripping is more than the equal of a pound of butter, and only costs half as much. We have here another example of the fact, already so often pointed out, that in buying foods we pay usually for the likings of the palate rather than for the needs of the body. For those who can afford it, that may be quite justifiable, but for the poor the advantages of margarine and dripping as cheap sources of fat cannot be too strongly insisted upon. * Butter-milk. Butter-milk is the fluid which is left after the fat has been removed from cream by churning. Its sourness is due to the presence of lactic acid, of which, however, it does not usually contain more than J to ^ per cent. Its general composition is shown in the two following analyses : Proteid. Fat. Carbohydrate. *■ 3'o 0-5 4-8' 2- 237 04 379 2 The chief point in which it differs from milk is its poverty in fat. In this respect it resembles skim milk. The loss of milk-sugar from the formation of lactic acid is too small to be of any significance. It is very easily digested, owing to the absence of fat and to the fact that its casein is present in a finely flocculent form. 3 Its nutritive value is considerable, an ordinary glassful yielding about as much nourishment as 2 ounces of bread. It is as a cheap source of proteid, however, that butter-milk is chiefly deserving of notice. In respect of this constituent, it is not one whit inferior to ordinary milk, and yet butter-milk is usually thrown out to the pigs. There can be no question that there is here a great waste of a very valuable food. When used in large quantities, butter-milk has diuretic properties which may be a slight disadvantage in health, but would rather enhance its value than otherwise in many cases of disease. Koumiss and Kephir. Koumiss is a milk preparation of very considerable antiquity. We find authentic accounts of it in books written early in the thirteenth 1 Alwater. 2 Dunlop, ' Report on Prison Dietaries,' p. 21, 1899. 8 The ease with which butter-milk can be digested has led to its being recom- mended as a food for infants (see a paper in the Brit. Med. Journ., 1902, ii. 692). KOUMISS AND KEPHIR 139 century, and hints of its existence almost as far back as the dawn of Christianity itself. Koumiss is fermented mare's milk. Kephir is a more modern substitute for it produced from the milk of the cow. The home of koumiss is in the steppes of European Russia and of Central and South- Western Asia. Its brewers are tribes of nomadic Tartars ; its source the milk of the hardy mares of the steppes. Kephir is, as it were, a spurious koumiss, and was first produced in the Caucasus Mountains from cow's milk fermented with kephir grains. 1 It may be regarded as bearing much the same relation to koumiss that margarine does to butter. It probably has, for all practical purposes, the same nutritive qualities and value as koumiss, but it is not the genuine article, and most likely it would never be used as a substitute were it not for the difficulty of obtaining mare's milk in civilized countries. The fermentation which milk undergoes in the process of conversion into koumiss or kephir is a double one. The sugar of the milk is partly converted into lactic acid by the same process which takes place when milk turns sour ; in part also it undergoes the same changes as those by which wine is produced from the sugar contained in the juice of the grape. A ' lactic ' and a ' vinous ' fermentation both go on. The former begins first, but the latter lasts longest, and the chief anxiety of the koumiss-maker is to promote the growth of the vinous ferment and to restrain that which produces lactic acid. Now, it is found that mare's milk is a better medium for this double fermentation than is the milk of the cow, and it is so, oddly enough, for those very reasons" which make it a poorer food than cow's milk. Mare's milk contains less casein and fat than cow's milk, but is richer than the latter in sugar. Not only so: the sugar of mare's milk seems to lend itself more readily to lactic acid fermen- tation than the sugar of cow's milk does. The richness of cow's milk in fat is a positive disadvantage in the process 'of fermentation, for there is apt to be produced from it small quantities of butyric acid, which is extremely irritating to the stomach, and renders the ' brew' unfit for consumption. So much is 'this the case, that even if the 1 Kephir grains resemble little fragments of cauliflower. Their fermentative power appears to be entirely due to the Saccharomyces mycoderma. In addition to this, they contain lactic-acid-producing organisms. The so-called Bacterium dispora Caucasica, which they also contain, does not appear to play any essential r61e in the process, unless, perhaps, it helps to liquefy the precipitated caseinogen (see Nature, 1884, xxx. 216 ; also Rothschild, ' L'Allaitement,' l^aris, 1898). For a full account of the history of kephir and the mode of preparing it, see ' Le Kephir,' by W. Podwyssotsky (Paris : C. Naud, 1902). This monograph also contains a very full bibliography. 140 FOOD AND DIETETICS mares are allowed to pasture on rich grass for but one day the milk of that day becomes unduly rich in fat, and cannot be safely used for the production of koumiss. 1 Hence it is that, if cow's milk is to be fermented — i.e., if one wishes to make kephir — it must first be made to approximate in composition to mare's milk by being skimmed or diluted, or even submitted to both processes. The chemical changes which take place in the milk under the double fermentation are not difficult to follow. The lactic ferment simply changes part of the sugar into lactic acid. The vinous ferment eats up a very small part of the proteid of the milk, and at the same time produces from the sugar a little alcohol and a good deal of carbonic acid gas. The milk thus becomes sour, it effer- vesces, and is weakly alcoholic. But the lactic acid causes the casein to be precipitated just as it does in the ordinary souring of milk, and the casein falls down in flocculi. Now, one of the essential points in the making of koumiss is that during the whole process of fermentation the milk should be kept constantly agitated by stirring. This agitation is primarily intended to permit of the access of oxygen to the fermenting fluid, but it has also the result of breaking up the precipitated casein into exceedingly fine particles, and it is to this extremely fine state of division in which the casein is found that much of the ease with which koumiss can be digested is to be attributed. As the process goes on, it would appear 2 that a small part, at least, of the casein undergoes a sort of spontaneous digestion, and is converted into soluble products. 8 One certainly finds that ordinary kephir contains a small amount of peptone. These changes, of course, only go on gradually, so that at the end of twelve hours of fermentation one gets a ' weak ' koumiss which is only slightly sour, and which still looks and tastes quite milky. After twenty-four hours- have elapsed some of the casein has been redissolved, with the result that the koumiss is thinner ; it has also increased in sourness. This is called ' medium ' koumiss. After another twenty-four hours or more most of the sugar has been destroyed, and the ' strong ' koumiss which results is a thin, sour fluid which effervesces briskly. In this form it can be kept in- definitely without undergoing much further change. The net change which has taken place in the original milk may be summed up by saying that the sugar has been to a large extent 1 Carrick, ' Koumiss,' pp. 45, 54. a Ibid., p. 41 ; also Food and Sanitation, May 22, 1897. ' Acid albumin, albumose and peptone {vide Food and Sanitation, May 27, 1897), KOUMISS AND KEPHIR 141 replaced by lactic acid, alcohol, and carbonic acid gas ; the casein has been partly precipitated in a state of very fine division, and partly predigested and dissolved, while the fat and salts have been left much as they were. That this is an accurate summary of what takes place is borne out by the following analyses : Proteid per cent. Sugar per cent. Fat per cent. Salts per cent. Alcohol per cent. Lactic Acid per cent. Kephir 2 Mare's milk 3 Cow's milk 4 . . Butter-milk 8 2-2 31 2-6 3'3 3'8 1 '5 1 '6 5 '5 4-8 3 '3 2-1 2"0 2'5 3-6 1-2 0-9 o-8 °'5 07 o-6 17 2 - I 0'9 o-8 0-3 It will be observed from the table that the total proteid is hardly less in koumiss and kephir than in mare's and cow's milk respectively. In koumiss the fat is practically the same as that in mare's milk, while the percentage of fat in kephir is naturally lower than that in cow's milk owing to its partial removal before fermentation is begun. The sugar in both milks is very considerably reduced, and is partly replaced by nearly 1 per cent., or sometimes even i£ per cent., of lactic acid. The amount of alcohol in both koumiss and kephir is less than 2 per cent. This is not more than the percentage present in many so-called temperance beverages, and is below the standard fixed by the Excise. As a matter of fact, it is impossible to get drunk upon koumiss, no matter how much of it is consumed. 6 At most only a slight degree of ' hilarity ' is produced, followed by sleepiness, but no headache. Looking at kephir in the light of what we have already learnt as to the digestibility of cow's milk, one will easily perceive that the process of fermentation must render the latter much more easily digested and absorbed than it is in its natural state. The casein — ■ the great obstacle to the easy digestion of cow's milk — is in such a form that it cannot form masses in the stomach, but is readily attacked by the digestive juices ; indeed, it is already partly digested. The carbonic acid stimulates the stomach to a more abundant secre- tion of gastric juice and promotes the absorption of the fat (see 1 Rubner, 'Leyden's Handbuch,' p. 93. 2 Ibid. 8 Wynter Blyth, ' Foods,' 4th edit., p. 258. ' Pearmain and Moor, ' Milk and Milk Products, ' p. 4. 5 Rubner, ' Leyden's Handbuch,' p. 94. s Dahl, quoted by Carrick, loc. cit., p. 113. 142 FOOD AND DIETETICS p. 124). The alcohol present co-operates in aiding the process of digestion by causing the blood to flow more briskly through the stomach and intestine, and in addition serves as a food itself. The lactic acid reinforces the digestive action of the acid of the stomach, and may, perhaps, in itself contribute heat and energy to the body.i In the matter of absorption koumiss and kephir also compare favourably with ordinary milk. May 2 administered to a patient 6,432 grammes of kephir in two days, containing 724 grammes of solid matter. He found that the percentages of loss in the stools were as follows : Dry substance . . . . . . 6*4 per cent Nitrogen .. .. .. .. o - 4 Fat 3-9 „ Ash 34-9 The absorption here was evidently better than that of milk, especially as far as nitrogen and fat are concerned. In the light of these facts one has no difficulty in understanding how it is that enormous quantities of koumiss or kephir can be disposed of in the body without any difficulty. We read, for instance, that the healthy dweller on the steppes is capable of con- suming 3 or 4 gallons of koumiss on a hot summer's day, while even the debilitated stomach of the consumptive is equal to disposing of ten large champagne bottlefuls in the twenty-four hours. 3 To the enormous quantity of nutriment thus obtained, rather than to any mysterious properties, the undoubtedly high curative value of koumiss in consumption and other wasting diseases is to be attributed. Postnikoff sums up its nutritive qualities in the three words, 'nutrit, roborat, alterat.' 4 It has also the advantage of possessing diuretic properties and of restraining intestinal putre- faction. It has been calculated that 4 litres (3^ quarts) of an average brand of koumiss will contain the following amount of nutritive material : Proteid . . . . . . . . 140 grammes = 600 Calories Fat 80 ,, = 744 Carbohydrate .. .. .. 140 „ = 574 ,, 1. 918 This is two-thirds of the total amount of Calories required by a man 1 For experimental proof of the greater digestibility of koumiss than cow's milk, see a paper on Kefir by Dr. Hallion (Journ. des Practiciens, p. 402, June 27, 1902). 2 Maly's Jahns-Bericht Thier-Chemie, 1895, xxv. 454. 8 Carrick, loc. cit. See also Dr. Stange on Koumiss Cures (Ziemssen's ' Hand- book of General Therapeutics,' appendix to volume on 'Dietary of the Sick'). 4 Food and Sanitation, May 27, 1897. CASEW PREPARATIONS 143 doing moderate work, and contains more than the entire amount of proteid he needs daily, and yet 3 J quarts of koumiss can be taken without any difficulty. 1 A glance at the table shows also that kephir is almost identical in composition with genuine koumiss ; indeed, being prepared from cow's milk, it is richer in casein, and must therefore be regarded as rather the better preparation of the two, unless for those of very feeble' digestive powers. Good kephir is now prepared by most of the large dairy companies, but it is still rather expensive, a large champagne bottleful costing about a shilling. In physiological properties it seems to be identical with the article prepared from mare's milk. The koumiss cure is -thus brought to one's own door, and no longer necessitates a journey to the steppes. In addition to its use in cases of phthisis, koumiss is of value in all conditions of impaired nutrition, in continued fevers, and in con- valescence. It may also be used with advantage in chronic catarrh of the stomach or bowels, in cases of hepatic cirrhosis, and in renal disease. It is often better borne in vomiting than any other form of food, and has been recommended in delirium tremens. 2 It should be given in small quantities at first (not more than a pint in the day) and in small doses, and gradually increased up to the limit of the amount which can be taken without discomfort. Koumiss is an acquired taste ; and though many patients object to it at first, they usually come to like it before long. Soured Milk, which somewhat resembles koumiss in its properties, and has recently obtained a wide popularity, is dealt with else- where (p. 557). Casein Preparations. In practical dietetics, the want of a tasteless, compact, easily digested and moderately cheap preparation of pure proteid is often felt. Casein is admirably adapted to meet these requirements, and has now been separated from milk and introduced as a dietetic pre- paration on its own account. The preparations known as Plasmon, Protene, Casumen, Biogene, etc., are examples of pure casein pre- pared in various ways. They contain about 80 per cent, of proteid. In these forms casein is digested with ease and absorbed almost 1 In the very dry atmosphere of the steppes these enormous quantities of koumiss can be taken, but in the damper climate of England only a more moderate amount can be compassed, 2 See 'Cow's Milk Koumiss as a Nutrient in Disease,' by Dr. Brush (Therap. Gazette, 1903, xxvii. 443). 144 FOOD AND DIETETICS in its entirety, and is capable, if necessary, of replacing all other forms of proteid in the diet. 1 Added to this, casein presents some special advantages not possessed by other varieties of proteid. For one thing, it is readily capable of ' fixing ' acids, and so neutralizing them. The power of casein in this respect is three times greater than that of an equal weight of beef. 2 This property gives it special advantages in those cases of dyspepsia in which too much acid is being poured into the stomach. Another valuable peculiarity of casein is that it contains phos- phorus, which is found also in the products of its digestion, and so enters the blood in an organic form, 3 rendering casein a valuable source of that essential constituent of all our tissues. We have also seen that casein is incapable of yielding uric acid by its decomposition, and its use is thus quite admissible in cases of gout. Lastly, casein is so easily and rapidly absorbed that it has but little opportunity of undergoing putrefaction in the intestine, even if it does not itself, as some have supposed, act as an intestinal antiseptic. 4 In these forms- casein is not clotted by rennet, but it is thrown down from its solution by the addition of acids in rather coarse flakes. It is better, therefore, to administer it mixed with other semi-solid foods, e.g., gruels or thick soup, rather than by itself. The nutritive value of these preparations is undoubtedly very high, containing as they do fully 80 per cent, of pure proteid. An invalid does not require more than 80 grammes of proteid daily, and this quantity would be covered by 100 grammes (3^ ounces) of Plasmon or Casumen. That an amount almost equal to this can be adminis- tered daily for prolonged periods has been fully proved by clinical experiment. 6 It is as a means of enriching the diet in proteid, rather than as sources of energy, that these preparations are specially valuable. Roughly speaking, one may say that one part of them is equal as a source of proteid to four parts of meat. Their tastelessness and solubility enables them to be added to other foods, such as soups, milk puddings, cocoa and jellies, raising greatly their nutritive value, 1 Rohmann, Berlin. Klin. Woch., 1895, xxxii. 519. 2 Brandenburg, Deut. Arckiv f. Klin. Med., 1896, lviii. 71. 8 Salkowski, Berlin. Klin. Woch., 1894, xxxi. 1063, and Deut. Med. Woch., 1896, xxii. 225. 4 See Salkowski, he. cit.; Schmitz, Zeit. f. Physiolog. Chemie, 1894, xix. 378; and Laquer, Verhandl. d. Cong. f. Inn. Med., 1898, xvi. 546. 6 See Oppler, Therap. Monatshejte, 1897, xi. 201. CASEIN PREPARATIONS 145 and without the patient being able to suspect that any such addition has been made. In many cases of illness, and especially, perhaps, in fevers and diabetes, they increase very considerably our dietetic resources, and have already taken an important place in treatment. They are far superior to any meat preparation as condensed forms of proteid. Sanatogen consists of casein combined with 5 per cent, of glycero- phosphate of sodium. In virtue of its casein it has the same nutritive value as the other preparations considered above. The organic phosphorus which it contains appears to be fully assimilated, 1 and is believed to exert a tonic effect upon the nervous system. Such an influence is conceivable, 2 but is very difficult of proof, and the claims of sanatogen in this respect rest upon a purely empirical basis, although it is only fair to add that numerous clinical observers have testified to the benefits derived from its use. 1 Tunnicliffe, ' Concerning the Behaviour in the Body of Certain Organic and Inorganic Phosphorus Compounds ' {Archives Internationales de Pharmacodynamic et de Therapie, 1906, xvi., fascicule 1 and 2). 2 For a discussion of the role of the phosphates in nutrition, see p. 296. M> [ i 4 6] CHAPTER IX CHEESE, EGGS, AND EGG SUBSTITUTES Cheese. i. Chemical Composition. Cheese consists essentially of the casein and fat of milk. It is prepared in two ways : i. The milk may be allowed to clot under the influence of rennet. If pure milk be so treated, the resulting cheese will contain most of the fat — e.g., Cheddar — and the proportion of fat may be rendered still greater by adding cream to the milk — e.g., some forms of Stilton. In other cases part of the cream is first removed by skimming. The cheese will then be proportionately poor in fat — e.g., some Dutch cheeses. 2. The casein may be precipitated by allowing the milk to become sour, or by adding to it an acid, such as vinegar. Under these cir- cumstances the casein carries down with it but little fat, and the cheese produced is a ' lean ' cheese — e.g., some Dutch and German cheeses. The nature of the cheese will also depend on the kind of milk from which it is derived. In by far the majority of cases cow's milk is the source, but Parmesan is made from partly skimmed goat's milk, and Roquefort from the milk of the ewe. In whatever way the casein is obtained, it is next squeezed to remove the whey which is contained in it. If high pressure be employed, the resulting cheese is ' hard,' while a lower degree of pressure produces a ' soft * cheese. The chief examples of hard cheese are these : Parmesan, Gouda, Edam, Chester, Cheddar, Roquefort. MANUFACTURE OF CHEESE 147 Amongst the soft cheeses are the following : Brie, Camembert, Neufchatel, Gorgonzola, Limburg, Stilton, and Cream. The soft cheeses do not keep well, and are intended for immediate consumption. After being submitted to pressure, the next step is to set the mass of casein and fat aside in a cool place to ' ripen.' This process is brought about by the agency of bacteria, and results in chemical changes in the casein which are not as yet perfectly understood. ' Amido bodies,' however, seem always to be produced, and a small amount of peptone. Whether or not the fat in the cheese increases at the expense of the casein is still disputed. The flavour of the cheese undoubtedly depends on the particular species of germ which has found access to it during the ripening, each species producing definite chemical bodies, which give to that particular kind of cheese its peculiar characteristics. The process seems to be analogous to that which takes place in the manufacture of wines. By the use of different yeasts, one can produce from the same grape-juice wines of entirely different character and bouquet. So with cheese. By the use of different bacteria one should be able to produce from the same casein cheeses of quite dissimilar flavour. No doubt that is what will happen in the future. At present cheese- making is a rule-of-thumb process. By-and-by it .will become a science. It has already begun to be so, indeed, in Germany and other countries, and even in some parts of England. The cheese- maker of next century will have a laboratory attached to his factory, in which pure cultures of the bacteria responsible for the flavour of each variety of cheese will be nursed, and instead of ' Stilton ' coming from one district, ' Gorgonzola ' from another, and ' Gruyere ' from a third, all will be produced under one roof. We may look forward then, perhaps, to tasting cheeses hitherto unknown, and to combina- tions of flavour as yet unsuspected. We may combine the virtues of Stilton with Gorgonzola, or those of Gruyere with Roquefort, for the artist of the palate will have in his hands the precise instruments of science. Whether this forecast be ever verified or not, there is little doubt that the gross chemistry of cheese will never be much altered. It must always remain, for all practical purposes, a compound consist- ing essentially of proteid and fat. In the accompanying table there is shown the average composition of some of the leading cheeses met with in the market : 10—2 148 FOOD AND DIETETICS COMPOSITION OF CHEESES. 1 Nitro- Average Real Cost Cheese. Water. genous Matter. Fat. Ash. Cost of 1 lb. of per lb. Nutriment. American 26 "9 32-9 31 4'5 6d. 81d. Brie 2 497 18-9 26-8 4'5 Camembert 48-6 21 - 217 4'4 II oz. , 6d. 8*d. Cheddar 31 "9 33 '4 26-8 3 9 9ld. is. 2d. Cheshire 33 - z 29'4 307 4'3 9id. is. 2d. Cream 32-0 8'6 35 '9 1 "5 Dutch 32 - 9 30-8 17-8 63 7 d. lo*d. Gloucester 31 9 367 247 4'4 9*d. is. 2d. Gorgonzola 39"2 25'9 269 47 9d. is. 3d. Gruyere 34"I 31 '5 282 4-0 iod. is. 3d. Neufchatel 41 - I4"3 43'2 1 '4 Parmesan 30-0 43-8 16-5 5"9 njd. is. 4fd. Roquefort 25-1 34-8 31 - 5 5'5 is. ijd. is. 6d. Stilton 27-6 23-9 38-9 31 is. 2d. is. 7d. St. Ivel 35*9 236 35 - o 37 — — Taking the results as a whole, one will not be far wrong in regarding cheese as made up of one-third of water, one-third of nitrogenous matter, and one-third of fat. It is well to remember, however, that there is no inconsiderable amount of mineral matter present as well, consisting chiefly of salts of lime, and that some cheeses at least may contain as much as 2 per cent of milk-sugar. The ' nitrogenous matter ' consists mainly, but by no means entirely, of proteids. Stutzer has estimated the different forms in which nitrogen occurs in Camembert, with the following results : 3 Total N .. .. .. =2'9 percent. N as ammonia . . . . =0-386 „ amides .. .. =1-117 ,, albumoses and peptone=o-885 „ casein and albumin =0-397 „ indigestible forms .. =0-115 The exact proportions of these different nitrogenous bodies will naturally vary considerably in different cheeses, but it is well to note the large amount of non-proteid nitrogen present, which must be allowed for in an estimate of the nutritive value of cheese. 2. Digestibility. The infiltration of cheese with the fat which it contains must always render it an article of diet not easily dealt with by delicate stomachs, for the fat forms a waterproof coating, which prevents the access of the digestive juices to the casein. 1 These figures are constructed by taking the averages of the analyses collected by Pearmain and Moor. Prices are those of the Stores. a Konig. 8 Zeit, f. Analyt. Chem., 1896, xxxv., p. 493. DIGESTIBILITY OF CHEESE i 4 g The larger the lumps of cheese which reach the stomach, the slower will this access be. Hence the importance of reducing the cheese to a state of fine division before it is swallowed. This may be done by careful chewing. Now, it is more easy to pulverize a hard morsel than a soft one, for the latter tends always to elude the teeth. For this reason, a piece of hard, dry cheese is more easily digested than a soft and moist piece. A better plan, however, is to break up the cheese before it is eaten at all. This may be done by grating, but a better way is to dissolve the cheese, and then mix it through some other form of food. An able writer 1 on the chemistry of cookery has pointed out that this may best be done by means of bicarbonate of potash. It was pointed out, when speaking of the chemistry of casein, that it forms soluble compounds with alkalies. Bicarbonate of potash is an alkali, and it seems to combine with the casein of the cheese, and brings the latter into a soluble state. As much bicarbonate of potash as will lie on a threepenny piece is sufficient to dissolve a quarter of a pound of cheese if the latter be first grated or chopped up into fragments. ' By the addition of milk and eggs, a very savoury and exceedingly nutritious pudding or fondu can be prepared, and at a very small cost. It is certainly much to be wished that we should avail ourselves more frequently of such a method of cooking cheese in this country. If cheese is ever to take the place that it ought to have as a cheap and convenient form of proteid food, some such method must be employed, for it is the difficulty with which cheese is digested that renders it an impossible food to many persons. 2 Another reason, probably, for the disagreeable effects which cheese is apt to produce in the stomach is that in the process of ripening small quantities of fatty acids are produced, and these are always very irritating. The addition of an alkali in the solution of the cheese will neutralize these, and render them less harmful. It is only in the stomach that the difficulty of digesting cheese occurs ; once in the intestine, it is absorbed as easily and completely as meat. 3. Nutritive Value. Of the high nutritive value of cheese there can be no doubt. It is just what would be expected when one remembers that a pound of, say, Cheddar cheese represents the total casein and most of the fat in a gallon of milk. 1 Mattieu Williams. 2 See also \The Claims of Cheese as a Substitute for Meat,' by Francis T. Bond, M.D. (The Sanitary and Economic Association, Ltd., 21, George Street, Gloucester). t$6 POOD AND DIETETICS The average amount of moisture which cheese contains is 33 p to bo « 13 ■S ."Si s Ssa ". '3 * — *- £ u „ c t» -3 -3-- 83 Sj-|"S s .1 OJ N 00 O S g B B < <" a .8 » .. •ssa i .1 ^ M — s ".2 1.5 I ."S^- 3-D — U ■O 2 S B B B o O > .Q •s< 5 o d = C o g» XI B •3 3 ■o B ■o rt £ aj B Sag « K„'S • "O bo J *j u ill 1 S S 5 • Si .5-5 '5 8 "S-df Sgi > C S rt « sell? .2 §«|S > g -va "§ a £■ fc: u -p o c d ^3 ui u"a>u) O S-- 3 U B-a ■ocn"" 10 " 2- 2' S S3 « 3-° b5 3 ■§■= S S.s ^sa°3 8,aJ J*"* to "O "S.SS c = 2 81 m •B £ 13 « |l EXl .n " 32-S- i.S-3 L - §§3.°° l& ci o o en Jr, rt 3 S 00 o o a OJ o ■a o (X i> o I ? 5^. bo C T3 S.5P ^3 rt O O .11 gti^^ a *in ifc- B'S d ' 6 s _ 0,0 a =• 3 ss-2.3 M" 3 * •> .a»-c S° 3 b „ ™ 3 W ^j -■S 5 3 3 .,tj.ESSS « --B o """-a < S'B-O S-o, b n s g .■o-gS^B-S^gEiS uiEbobo.-.aSxiSo'BiX'um^ > <<< W < < < < J ^TD •« "I'd B a S-a 2-a-S a B.<8 6 « o E s a 2 » SJi S^ « S S o ^ i-5 2 ES E-sgfiSxi.^u a .a BU bo 1^ a-S a -a O rt o u .SB 8.11 •s-s E c O cd ;r ^ *5 w •a oj 03 3 J3 U a) o 5 S i*-SS * E("u < <<< 1 " onSi) „, „ C 3 £ g ~ boa a = 2 .S JB » .S-S.S5- b/!faO° o"^ O — -c _, — ^S|2^mo« S << < fco C . *S d rtU O c u « .•c c O '(u E o • ~ a a) £ "-a .".■§ •IS -8 S8S < nO"i m M efl M ,bl .£ 3 S3 ts t^ IN b b b P o p> 00 VnCs uo»o o 00 2 ^ w S >* Si! £,0 ^ >.S rt u c ="3-3 *£ boo >> B O X V e V •3 Si I-3g o o .a 73 2 3 B '3 « -C ^ 5 aj - s c ■s * * P : -3 B >a; £ "■J 3 ZSQ 01 rt a •asll « as boja • 8 g e« O5 BO 5 u «— X O M n 204 FOOD AND DIETETICS In analyzing these breads the nitrogen was estimated by Kjeldahl's process, and the proteid calculated from it, using the factor 5-7. The ash was determined in the usual way. The carbohydrates were estimated by difference. Only a few fat estimations were made, the fat being usually included in the carbohydrates owing to the small amount of it present, and its unimportance as a nutritive constituent of bread (it may be taken to be usually less than i£ per cent.). The bread was analyzed in each case on the day after baking. The analysis of ' Bipsine ' bread was that given in the Lancet of Decem- ber 4, 1909. There are also various patent and fancy breads in the market. Of the former the different varieties of Vienna bread are a good example. These are made from very fine flour (' patents ') fermented with compressed yeast, milk being often added to the dough. The crust is glazed by being subjected to the action of overheated steam before leaving the oven. Of the patent breads, the majority are of the ' brown ; variety. They are made from flours prepared by various patent processes. Some of them are wholemeal breads, in which the bran has been reduced to varying degrees of fineness ; others contain the germ in various proportions, of which ' Hovis ' is the best-known example. Others, again, are malted. The malting of bread consists in adding to it malt-extract, obtained by evaporating an infusion of malted barley to a syrupy consistency at a low temperature. The solid part of the malt-extract so prepared consists mainly of malt-sugar and dextrins. But it also contains the ferment diastase, which is able to convert starch into soluble substances (maltose and dextrin). When, therefore, malt-extract is mixed with the dough part of the starch, the latter is ultimately converted into malt-sugar and dextrin. In other words, part of the starch is digested. This has the effect, as already pointed out, of making the bread keep longer moist. Now, it is important to remember that this ferment diastase is readily killed if exposed to a high temperature. Hence its activity inevitably ceases whenever the bread enters the oven. If, then, any considerable part of the starch of the dough is to be converted, the malt-extract must be added very early in the process. As an alternative to that it may be added to a separate part of the flour, and the latter mixed with water and kept at a moderate temperature till most of its starch has been changed, and this mixture added to the dough just before baking. This is the peculiarity of Montgomerie's process, by which ' Bermaline ' bread is made. But even under these favourable conditions not much more than 10 per cent, of the carbohydrates of the loaf are in a soluble MALTED BREADS 205 form, while in ordinary bread about 4 per cent, is so changed. Seeing, also, that the diastase is killed by the act of baking, it is obvious that malted bread cannot truly be said to aid the digestion of other starchy foods. In the preceding table the composition of most of the patent breads is shown from analyses made by the author. 1 The special peculiarities of each kind are also briefly indicated. We shall consider the nutritive and economic value of these breads later. The comparative composition of the crust and crumb of white bread is given by Barral as follows : Crust. Crumb. Water 1715 4445 Insoluble proteid 730 592 Soluble ,, .. .. .. 570 075 Dextrin and sugar .. .. .. 4-88 3'79 Starch 6258 4355 Fatty matters . . .. .. .. 118 070 Ash .. .. .. .. .. 1 -21 084 The most striking point about these figures is the much larger proportion of solids in the crust, and the larger amount of soluble proteids and carbohydrates which it contains. Changes which Bread undergoes on Keeping. When bread is kept it becomes dry from loss of water. The loss, however, is not a very rapid one. The following are the average results of fifty observations by Goodfellow : 2 A 2-lb. Loss Loaf loses per cent. In 12 hours £ oz. 09 „ 24 „ § ,. 20 „ 36 „ 1* ,. 5° „ 48 „ 2ft „ 80 „ 60 „ 3i .. «*o „ 72 „ 44 .. 1 4'° At the end of a week 14 per cent, of the original water is gone, and after a month 18 per cent. (v. Bibra). The bread also becomes stale. The staleness is not entirely due to the loss of water, for, as was long ago shown by Boussingault, one has merely to heat the loa| up again to a temperature of about 300° F. in order to restore much of its freshness. Yet in the course of this rebaking it loses considerably more water than it had already lost by evaporation. The explanation of this rather surprising result is not yet clear. It 1 In addition to the breads described in the table, mention may be made of 'Turog,' which is a malted brown bread made from flour derived from various cereals, and ' Bananine ' bread, which contains banana flour. 2 ' Dietetic Value of Bread,' p. 139. 206 FOOD AND DIETETICS may be that in fresh bread there is some free water present, which becomes united with starch or gluten as the bread grows stale, and that the rebaking sets it free again. That is the explanation of v. Bibra, 1 who has also shown that the freshness will not return if the bread has already lost 30 per cent, of its water. Mattieu Williams, 2 on the other hand, believes that the staling of bread is due to the shrinkage and coming together of the fibres which form the walls of its visible pores. The water vapour generated by the rebaking drives these fibres apart again. Boutroux 3 has still another explana- tion. He believes that the apparent dryness of stale bread is due to a shifting of moisture from the crumb to the crust. When first taken from the oven the dry crust cools quickly, whilst the moist crumb retains its heat much longer ; but as its temperature gradually falls the moisture which it contains tends to distil outwards into the crust. When the loaf is rebaked the moisture is driven back again into the crumb. In former days, when good flour was more expensive, adulterants used often to be added to bread. Of these alum was one of the most harmful. Flour which has been produced from badly ripened grain, or which has been kept for some time under bad conditions, does not form good dough. This is owing to a too great solubility of its proteids. Alum seems to unite with these so that they become insoluble, and the dough regains its toughness and power of holding water. Sulphate of copper and lime act similarly, and by the aid of these substances an inferior flour could be used for bread-making. Fortunately, these adulterations appear to be things of the past, and it is comforting to learn that ' it is now certain that the bread supplied to the people of England is practically pure ' (Goodfellow). The cooking of bread is practically confined to the application of dry heat. This has the effect of driving off water, and of rupturing some of the starch grains, and converting them partly into soluble starch and dextrin. A little caramel also is produced. The result is toast. ' Pulled bread ' is made by pulling out the interior of a new loaf and thoroughly baking it. The same changes occur in, it as in toast, only to a greater degree. Biscuits are made from fine flour either alone or with jthe addition of sugar, butter, milk, flavouring agents, etc. Baking- 1 V. Bibra, 'Die Getreidearten und das Brot,' Niirnberg, i860; see also Lehmann, Archiv f. Hygiene, 1894, xxi. 215. 2 " Chemistry of Cookery,' p. 209. 3 Cited in ' Bread and the Principles of Bread-Making,' United States Depart- ment of Agriculture, Farmers' Bulletin, No. 112, p. 29, igoo. BISCUITS AND RUSKS 207 powder is sometimes added to make them rise a little. They con- tain very little water (about 5 per cent.), and 3 pounds of them may be taken as equal in nourishment to 5 pounds of bread (Church). The following table shows an analysis of some by Bauer : COMPOSITION OF BISCUITS. Fine Wheaten Biscuits. Other Wheaten Biscuits. English Biscuits. Nitrogenous matter Fat i-i8 13-31 318 7-12 7396 025 10 1007 "'93 7'47 3638 32-29 075 114 7'45 718 928 Other carbohydrates Mineral matter . . 1702 5808 016 083 Busks may be regarded as a kind of toast. They are made in much the same way as bread, but with the addition of butter, sugar and milk, and are twice passed through the oven, after which they are thoroughly dried. In the next chapter we shall consider the digestibility and nutritive value of bread. [ 208 ] CHAPTER XII BREAD (continued) — OTHER CEREALS Digestibility and Absorption of Bread. The digestion of bread takes place, in part at least, in the mouth, by the conversion of its starch into dextrins and maltose under the action of the saliva. The more thoroughly bread is chewed and ground into particles, the more complete will the transformation of the starch be. It is on account of the greater ease with which they can be pulverized by the teeth that toast and biscuits are more easily digested than ordinary bread and stale bread than a newly- baked loaf. The dryness of toast and biscuits, too, enables them to become easily saturated with the saliva, and that also greatly facilitates digestion. Further, it must be remembered that a considerable proportion of the starch in biscuits and toast has been already converted into soluble forms in the course of their prepara- tion, so that the labours of the digestive juices in their case are considerably lightened. For these reasons also the crust of bread is more digestible than the crumb, for it is drier, and contains a higher proportion of carbohydrates, owing to the more intense action upon it of the heat of the oven. , The notorious indigestibility of new bread, on the other hand, is due to its moistness, which makes it difficult to chew, and at the same time prevents it from soaking up the saliva. As regards the duration of its stay in the stomach, bread occupies a middle position among the vegetable foods, 70 grammes (2^ ounces, or an ordinary slice) having completely left the stomach in two hours and twenty minutes, while 150 grammes (5^ ounces, or two rather thick slices) remain about an hour longer. These periods cannot really be regarded as long when one bears in mind the comparatively large amount of solid matter which bread contains. 1 White bread is 1 Penzoldt, Deut. Archivf. Klin. Med., 1893, li. 535. ABSORPTION OF WHITE BREAD 209 disposed of by the stomach rather more quickly than black (e.g., pumpernickel), but there is no appreciable difference in this respect between the behaviour of wholemeal bread and that made from fine flour. The presence of bran in wholemeal bread, however, may act as ballast in the stomach, and give to it the greater ' sustaining ' power with which it is commonly credited. Considering the large amount of solid nutriment which they contain, biscuits must be regarded as considerably more digestible than ordinary bread. New bread, unless very thoroughly chewed, offers greater resistance to the stomach than stale bread, owing to its tendency to form doughy masses. In the intestine the digestion of the starch and proteid of bread is completed, and absorption takes place. On the whole, white bread is very thoroughly absorbed. Even when large quantities are consumed, the loss of nutritive constituents is only about as follows :* Percentage unabsorbed. Total solids . . • • • . . . . . 4 J Proteid 20 Mineral matter 25 Carbohydrates 3 It will be noted that the greatest share of loss falls to the proteids, of which about one-fifth escapes absorption. This contrasts very strikingly with the case of meat, in which the proteid is absorbed almost in its entirety. The defective absorption of the proteids in bread is apparently due in part to the large amount of starch present ; 2 in part, also, it may be only apparent, and explicable by the fact that bread requires a large production of the digestive juices for its complete solution (see also p. n). The above experiments apply to cases in which bread formed the main part of the diet. When given along with other foods, its absorption appears to be considerably increased. Thus, five experi- ments on an exclusive bread diet showed an average absorption of 82 per cent, of the proteid and 99 per cent, of the carbohydrates. When 2 litres (3 J pints) of milk were added to the diet, the absorption of proteid rose to 97 per cent., while that of the carbohydrates remained stationary. Ten experiments on milk alone showed a 1 From the average of a considerable number of experiments by Rubner, Atwater, Zuntz and Magnus- Levy, Goodfellow and others. The quantities con- sumed were very considerable, amounting to from 600 to 1,000 grammes per day. 3 See experiments by Meyer, Zeit. f. Biolog.,i8'ji, vii. 1. 14. 2io FOOD AND DIETETICS proteid absorption of 92 per cent., and an absorption of the carbo- hydrates to 86£ per cent. 1 This is another instance of the general rule, that a mixture of foods is better absorbed than any one food by itself. The carbohydrate of bread corresponds to the proteid of meat in being almost completely absorbed into the blood. On the other hand, it is rather surprising to find that, of the comparatively small amount of mineral matter met with in bread, one-fourth is excreted unabsorbed. Seeing that this is the case, it is surely futile to recommend the use of bread containing a larger amount of mineral constituents. Relative Absorption of White and Wholemeal Bread. Brown and wholemeal breads differ from white bread, as we have already seen, in containing more or less of the bran of the wheat. Any difference which they show in absorbability, therefore, when compared with white bread, will depend probably on this peculiarity. Now, bran contains a large amount of cellulose, some analysts placing the proportion as high as 20 per cent, or more. 2 Not only so : the cellulose of bran is in a dense and woody form. It has already been pointed out that, at the best, cellulose is but imper- fectly digested by man, and that when it becomes woody it is hardly digested at all. Hence one would expect the constituents of bran, enclosed as they are by woody cellulose, to be but indifferently absorbed. Experiment fully justifies this expectation. Donders 3 observed that the walls of bran cells were digested by herbivora, but not by man ; and Giraud was able to demonstrate the aleurone cells in the human excreta unchanged — an observation which has been more recently confirmed by Moeller.* Pozziale, 5 too, found that bran, which had originally contained 13 per cent, of nitrogenous matter, still retained fully 3J per cent, after traversing successively the digestive apparatus of two dogs and a hen. One is therefore not surprised to learn that Rubner 6 found that only one-third of the nutriment contained in bran is capable of being made use of by the human digestive organs. 1 Bull. 53, United States Department of Agriculture, Office of Experiment Stations, p. 43. 2 Lebbin, Archiv f. Hygiene, 1897, xxviii. 212. 8 Quoted by Meyer, op. cit. 4 Zeit. /. Biolog., 1897, xxxv. 291. This writer gives an exhaustive summary of the results of previous workers upon the digestion of various cells as tested by microscopical examination of the stools. 6 Quoted by Meyer, op. cit. e Zeit. f. Biolog., 1883, xix. 45. ABSORPTION OF WHOLEMEAL BREAD 211 Seeing that, of the total amount of mineral matter which whole- meal bread contains, fully 65 per cent, belongs to the bran, one would expect the mineral constituents of such bread to be specially singled out for defective absorption. 1 And this is so. Fully half of them never enter the blood at all (Rubner, Goodfellow, and others). The carbohydrates, too, of wholemeal bread are not so completely absorbed as those of white bread, more than 5 per cent, being lost. 2 Some observers, indeed, have found a greater difference between the absorption of wholemeal and white bread in respect of this constituent than in regard to any other. The results of observations on the absorption of the proteids of wholemeal bread are by no means unanimous. Some experimenters (e.g., Goodfellow) have found but little difference between the behaviour of wholemeal and white bread in this respect, while others (e.g., Meyer), comparing whole wheat bread with moderately fine rye bread, have found a difference of 10 per cent, or more in favour of the latter. Some of the most conclusive experiments on this point may be cited here. Rubner 3 compared the relative absorption of bread made from the three following flours: (1) Finest white flour (' patents ') ; (2) middle quality (' seconds ') ; (3) ' wheatmeal flour.' In making the loaves, the directions of the Bread Reform League . were followed. Upwards of 600 grammes of tie bread were eaten daily, the amount of nutrients contained in each case being as follows : Nitrogen. Fat. Carbo- hydrates. Mineral Matter. No. i. 1020 669 528-8 239 .. 2. 13-19 5'65 507-9 285 .. 3" 1245 1265 5045 854 Bread No. 1 contained 6£ 1*5 per cent, water ; No. 2 had 69/4 per cent. ; No. 3, 62-4 per cent. The percentages of loss from non- absorption were these : Quantity Percent. Percent. Bread of Dr 5 r Dry Percent. Percent. Carbo- Percent. Breaa - Substance Substance N lost. Fat lost. hydrate Ash lost. eaten. lost. lost. No. i. 6153 grammes 403 2007 4469 no 1928 „ 2. 6126 „ 666 2456 6283 257 30-35 „ 3- 617-1 1223 3047 5I-I4 737 4498 1 There is some reason to believe, however, that wholemeal bread is capable of yielding a. larger amount of iron to the body that white bread. (See United States Department of Agriculture, Bulletin 185.) 2 Moeller, however (Zeit.f. Biolog., 1897, xxxv. 2gi), states that he could find no starch cells in the faeces, even when Graham bread was eaten. Notwithstanding this, he decides the question of wholemeal versus white bread entirely in favour of the latter. 3 Zeit.f. Biolog., 1883, xix. 45. 14 — 2 212 FOOD AND DIETETICS The absolute losses were : Fresh Fjeces. Dried. N. Fat. Carbo- hydrates. Ash. No. i. I3Z7 248 217 2'99 583 2'39 .1 2. 2528 408 324 3'55 13-10 3 9° .. 3- 3178 757 380 647 3723 834 He draws special attention to the great absolute loss of carbo- hydrate in the wholemeal bread. More recent experiments have been made in America, 1 in which the absorption of bread made from ' patents ' and ' bakers' ' flour respectively was studied, 672 grammes (24 ounces) of bread being taken daily. The results were : Per Cent. Digested. B™* M D a t L. Troteid. ^ &%L "Bakers'" 942 gi - d 94-6 968 •Patents' 94-4 905 947 969 No difference was found in this case between the two kinds of bread. In another set of experiments, 2 white bread, entire wheat, and Graham bread were compared, with the following results : 100 Grammes of Bread yield in the Body. Calories. Proteid. White bread 269 8 6 grammes. Entire wheat bread .. .. 235 8 6 ,, Graham bread 218 83 ,, Taking the results as a whole, it may fairly be concluded that the proteid of wholemeal bread is not so well absorbed as that of white bread. Even bread made from decorticated wheat does not offer the advantages often ascribed to it, for exact experiment has shown that it is not much better absorbed than ordinary wholemeal bread. 3 The defective absorption of wholemeal bread is no doubt to be attributed to the large amount of cellulose which it contains. The cellulose acts chiefly by preventing the access of the digestive juices to the nutritive ingredients which are enclosed in it. It is also sometimes said to interfere with absorption by hurrying on the contents of the intestine by the stimulating influence which it exerts on peristalsis. This would appear, however, to be an error, for Rubner found 4 that, on the whole, the faeces on a coarse bread diet 1 United States Department of Agriculture, Office of Experiment Stations Bulletins 67, 101, 126. 2 United States Department of Agriculture, Farmers' Bull. 112. See also Bulls. 85 and 101, Office of Experiment Stations, 1900 and 1901, p. 35, 1900 of the same Department. s Menicanti and Prausnitz, ' Untersuchungen fiber das Verhalten verschiedener Brotarten im Menschlichen Organismus ' (Zeit. f. Biolog., 1894 xxx 328) * Op. cit. '' COMPARATIVE ABSORPTION OF BREADS 213 were more slowly evacuated than those of fine bread. On the other hand, the residue of wholemeal bread seems more prone to undergo fermentation, with the production of acids, and it is to this that the greater wateriness of the wholemeal bread faeces is to be attributed, for the intestine endeavours to neutralize the acids by a greater flow of alkaline fluid. It is probably for this reason that wholemeal bread interferes somewhat with the absorption of other foods. Thus, Goodfellow 1 has found that the waste in milk is greater by 3 per cent, when given along with oatmeal bread than when taken alone. This, as we have seen, is the very reverse of the effect exercised by ordinary bread. Taking the mean results of available experiments, one may con- trast the absorption of the constituents of white and wholemeal bread thus: Ti77 -i d j Wholemeal White Bread. Bfmd Total solids .. .. 4 J per cent. 14 per cent. "j Proteids .. .. ..20 „ 20 to 30 „ li__ f Ash 25 ,. 51 - J Carbohydrates .. •■ 3 .. <5 J These results, which were all obtained from observations on healthy human beings, are entirely confirmed by experiments on the digestibility of bread in the laboratory by means of artificial juices. By this method Brunton and Tunnicliffe 2 found that sugar is pro- duced much more rapidly from white bread than from brown, and that 14 per cent, more of the nitrogenous matter was dissolved in the former case than in the latter. Goodfellow, 3 by a very similar method, had already obtained the same result. It might reasonably be contended that the defective absorption of the constituents of bran is due to imperfect grinding, and that if the bran were reduced to as fine a powder as the flour it would be as well digested as the latter. To some extent this is true, and brown breads made from finely ground patent wholemeals are unques- tionably better digested than the ordinary coarse brown bread. Observations by Romberg, 4 however, on the digestion of rye bread, show that, no matter how well ground the bran is, it is never as well absorbed as the flour. He prepared a series of breads from rye, the meal used being in each case of equal fineness, but differing in the proportion of bran contained. Thus, bread No. I 1 ' Dietetic Value of Bread, ' p. 199. In this work will be found numerous experiments on the absorption of wholemeal bread. 2 ' St. Bartholomew's Hospital Reports, ' 1897, xxxiii. 157. 8 'Dietetic Value of Bread,' pp. 183, 184. * Romberg, Archiv /. Hygiene, 1897, xxviii. 244. 214 FOOD AND DIETETICS consisted of the flour only and was perfectly white, while No. 4 was made from the whole grain and was very dark ; Nos. 2 and 3 were of intermediate quality. The following tables show the composition of the meals used and the percentages of waste in the digestion of the corresponding breads : COMPOSITION OF THE MEALS. In Dry Substance ^"" ^•~- Water. Proteid. Fat. Ask. Carbo- hydrate. No. 1. 11-25 743 009 049 91-09 .1 2. 11-84 "■59 1-14 0-92 8635 .. 3- 11-26 1728 2-13 1-89 78-70 .. 4- 11-40 1684 213 2-22 7881 iRCEN TAGES UNDIGESTED IN THE CORRESPONDING BREAD Dry Substance. Proteid. Ash. Carbo- hydrates, 1 itc. No. 1. 4- 15 220 588 I 66 .. 2. 751 286 75'5 4'I5 .. 3- 1364 305 74'4 808 „ 4. 2007 430 61 g 1440 Seeing that the ingredients of the bread were in an equally fine state of division in every case, the author concludes that even bran flour is not suitable for human food, and that no method of preparing it will make it as capable of being absorbed as white flour. Whether finely -ground wholemeal bread yields more mineral constituents (especially phosphates) to the body than white bread has not been definitely settled by experiments, although from the observations of Rubner already cited, the absolute yield of mineral matter would seem to be greater in the case of wholemeal bread. Seeing, however, that an ordinary mixed diet always contains an excess of phosphates, there is usually nothing to be gained by increasing the amount of these ingested. In any case a large proportion of the phosphates in ordinary bread are present in organic combination, and are therefore more available for nutrition than the mineral phosphates of the bran. On the other hand, where bread forms the chief constituent of the diet, the use of a finely-ground wholemeal bread is advantageous from the mineral point of view. The absorption of wholemeal bread has been dwelt upon at con- siderable length, for reasons that will be apparent when we come to consider its nutritive value. As regards the digestibility and absorption of bread in general, it only remains to be added that there is some reason to suppose that custom plays a considerable part in it, and that people who are habitually large bread-eaters LACK OF PROTEID IN BREAD 215 acquire 'the power of digesting it more completely than those who are not so habituated to its use. 1 Nutritive Value of Bread. Weight for weight, though not bulk for bulk, bread must be regarded as one of the most nutritious of our ordinary foods. This is due largely to the fact that three-fifths of it consist of solid nutriment, and but two-fifths of water, and there is no animal food and but few cooked vegetable foods of which the same can be said. Of the chemical constituents necessary for proper nutrition, bread yields to the blood a large proportion of carbohydrates, a moderate amount of proteid and mineral matters, but almost no fat, The fact that bread is usually eaten with butter, however, renders the absence of fat a consideration of but little importance. Yet bread cannot be regarded as a perfect food. The proportion of proteid to carbohydrate is too low. An ideal food would contain one part of proteid to 4*2 parts of carbohydrate, whereas in white bread the proportion is only 1 to 8|. In order to obtain from bread the proteid requisite in an ordinary diet, a whole 4-pound loaf must be eaten every day, and that would contain more than twice as much carbohydrate as one really requires. To the ordinary mixed feeder this does not matter, for he supplements the deficiency of proteid by adding to the bread a ' proteid-carrier ' such as meat, milk, or cheese. Where bread forms the staple article of diet, however, as it does in many poor households, this lack of proteid must be regarded as a serious drawback. Various methods of overcoming it have been tried, all of which consist in adding to the flour some other highly nitrogenous substance. Feasmeal has been used with this object, and when added to flour in equal proportions is said to make a good loaf. Skim milk has also been employed. A loaf made entirely with skim milk had the following composition when compared with a loaf made from the same flour and water : 2 Milk Loaf. Water Loaf. Water 3129 32'59 Proteid 973 875 Carbohydrate 56-66 5665 Fat 0*96 o-86 Ash 139 115 Meat has also been proposed as an addition, 2 pounds of flour 1 See Rubner, Zeit. f. Biolog., 1879, xv. 154. 2 Sartori, quoted by Stutzer, Weyl's 'Handbuchder Hygiene,' iii. 251. Some American analyses (' The Digestibility and Nutritive Value of Bread,' Bull. 85, United States Department of Agriculture, Office of Experiment Stations, 1900) also showed that the chief difference between bread made with skim milk and ordinary bread is that the former contains 1 per cent, more proteid in the fresh substance than the latter. ai6 FOOD AND DIETETICS and i pound of cooked minced meat making a good and digestible loaf, which, with the addition of fat, is almost a complete food. More elaborate methods are by the addition of Aleuronat or of casein. Aleuronat was introduced by Dr. Hundhausen. It is simply gluten prepared in a special way, and contains 80 per cent, of proteid. It is a colourless, odourless powder, which is well digested and absorbed, and when added to flour in the proportion of 1 part to 3 yields a loaf containing nearly 20 per cent, of proteid, at a cost but little above that of ordinary bread. 1 The addition of casein is employed by the Protene Company in their household Protene bread, 25 per cent, of casein being added to ordinary flour. The resulting loaf is very rich in proteid, but, owing to the price of casein, is necessarily rather expensive. It must be admitted that none of these methods of increasing the amount of proteid in bread is altogether adapted for ordinary use, and that they are all apt to make the cost of the bread too great. Perhaps one or other of the germ breads now in the market, of which Hovis is the best example, meets the requirements better than any substitute which has yet been proposed. About 3 pounds of such a bread would supply all the proteid required daily, and would only contain a slight excess of carbohydrate. With the free addition of butter or some other fat, it is not far from being a com- plete food. Unfortunately, there are not many experiments avail- able to determine whether or not the ' germ ' is well absorbed. Goodfellow 2 has given some attention to the matter, however, in the case of Hovis bread, and found that the loss was only very slightly above that of ordinary white bread. Putting aside such patent breads, it may be said that white bread made from ' seconds ' flour will yield more nitrogen to the body than a bread made of ordinary flour, and still more than one made of ' patents.' The reasons for this have already been discussed (p. 193). When we pass on to consider the relative nutritive values of white and wholemeal bread, we are on ground which has been the scene of many a controversy. It is often contended that wholemeal is preferable to white bread, because it is richer in proteid and mineral matter, and so makes a better-balanced diet. But our examination of the chemical composition of wholemeal bread has shown that, as regards proteid at least, this is not always true, and even were it the case, the lesser absorption of wholemeal bread, which we have seen to occur, would tend to annul the advantage. As regards mineral 1 Carl Voit, Archivf. Hygiene, 1893, xvii. 408. a ' Dietetic Value of Bread,' p. 255. ECONOMIC VALUE OF BREAD 217 matter the evidence is not so clear, and there is some reason to believe that the absolute yield of these constituents to the body is greater with wholemeal bread, especially if it be finely ground. In the case of an individual living upon an ordinary mixed diet, how- ever, this advantage is not a matter of great importance. Where bread constitutes the chief source of nutriment, as 'is unfortunately only too often the case, it is probably wisest to use the old-fashioned household bread, which is not brown but cream- coloured, and which includes both the germ and semolina. This is certainly superior to ordinary white bread from a chemical point of view, whilst it is in no way inferior to the latter in digestibility and capability of absorption. Economic Value of Bread. Bread is not only one of the most nutritious, but it is also amongst the cheapest of foods. In an earlier chapter we saw that for a given sum one obtains a larger number of Calories from bread than from any other food. As regards the actual amount of dry nutriment obtained, bread also heads the list. Thus, A pennyworth of bread yields oatmeal lentils potatoes rice cheese carrots fish meat 8 oz. of dry nutriment 74 .. 54 54 .. 5i 2i .. 2 I o* (Goodfellow.) Taking proteid alone as the standard, it is found that bread is a fairly cheap source even of that constituent. Thus, x pound of proteid > 1 costs in the form of flour , , maize , , beans , , oatmeal , , bread , , cheese , , rice „ milk • 5i<3. 6d. 7 rf. 74d. . is. 2d. . is. 3^. . is. 5d . 2S. 2J,li. 1 1 beefg-P est . is. 4^d. ■ 4S- 5d- , eggs . 5s. ojd. Cheap food though it be, bread is dear when compared with the cost of flour. As a matter of fact, it has been found that bread costs just twice as much as the ingredients required to make it ;* in other words, half the cost of a loaf represents the value of the baker's trouble 1 See Bulletin 52, United States Department of Agriculture, Office of Experi- ment Stations. 2i8 FOOD AND DIETETICS and time. It follows from this that, where economy is important, it would be cheaper to bake bread at home than to buy it from the baker. Of the patent and fancy breads as a whole, it may be said that they are relatively somewhat dearer than white bread. About i^d. per pound may be regarded as their average cost. Even ordinary brown bread has ceased to be cheaper than white, and cannot there- fore be recommended on that ground. I may conclude this subject in the words of Dr. Goodfellow : 1 ' It will be perfectly clear . . . that bread is one of the cheapest foods, not only with regard to the actual weight of nourishment obtained, but also with regard to the variety of the nutrient constituents ; and the purchaser who expends his modest i\&. on a 2-pound loaf may rest assured that he could not spend his money to better advantage, except, perhaps, in the purchase of oatmeal, which contains slightly more energising nutriment than bread.' Bread has been dwelt upon at some length on account of its great practical value. The other food-stuffs derived from wheat may be dismissed more briefly. Semolina is prepared from the central part of hard wheats which are rich in gluten, and is largely used in the South of Europe. It contains about n per cent, of proteid, or half the amount contained in an equal weight of beef. It must thus be regarded as a fairly nitrogenous vegetable food, and is useful for making puddings, porridge, thickening of soups, etc. Macaroni, vermicelli and the Italian pastes are also made from flours rich in gluten. The flour is made into a paste with water, and the viscidity of the gluten then allows it to be moulded in various ways or drawn into tubes. It is afterwards dried or slightly baked. Macaroni and vermicelli absorb about three times their weight of water in the process of cooking, so that the product when eaten, although highly nutritious, is about eight times poorer in nitrogen than a similar weight of beef. Macaroni and vermicelli are absorbed almost in their entirety. 2 Their use is therefore indicated in conditions where it is advisable to leave behind as small a residue as possible in the intestine. The following table represents the composition of these and some similar preparations from recent analyses by Balland : 1 ' Dietetic Value of Bread,' p. 106. * Rubner, Zeit. f. Biolog., 1879, xv. 165. PATENT PREPARATION OF WHEAT 219 COMPOSITION OF ITALIAN PASTES, ETC.* Water. N Substances. Fat.- Starch, etc. Cellu- lose. Ash Macaroni (1895) IICO 1098 °'45 7605 0-28 064 (1897) 1200 1089 065 757° 026 050 Vermicelli (1896) I090 1174 050 7574 038 074 (1897) •• IOOO 1251 080 7551 028 090 Pates d'ltalie (1897) • • IO4O 12-51 080 7523 030 076 Semolina (1895) 920 1350 085 75-45 050 050 „ (1896) 920 10; 42 o-55 7863 045 075 ., (1897) I050 1 1 96 060 7579 050 065 Rice semolina (1898) . . 1080 734 030 8096 040 020 Foreign tapioca (1897) I2-8o 000 020 8688 008 004 French potato tapioca (1897) l60O 0'45 015 8295 OOO 045 The following are some patent preparations of wheat : Granuto 2 is a wheat product which has been thoroughly cooked and subjected to the action of malt sufficiently to convert a consider- able proportion of its starch into dextrin and maltose. Granola is a whole-wheat preparation manufactured by Mr. James Marshall in this country. 3 The same maker produces a granular preparation of the endosperm of wheat under the name of Farola. Florador is another wheat product of recent introduction, and in a granular form. It contains io-6 of proteid and 03 per cent, of mineral matter, and is recommended for use in the making of blancmange, etc. It is undoubtedly far more nutritious than such preparations as cornflour, which are so commonly used for a similar purpose. The composition of some of the above preparations, when cooked with water in the usual way, is as follows : 4 Water. Proteid. Fat. Starch. Cellulose. Mineral Matter. Semolina 9017 1-93 0-08 7Z5 004 013 Vermicelli 87-14 2-44 OOI 1082 007 0-13 Hominy 8663 281 009 987 o - i6 002 Farola (fine grain) 9024 I 84 002 7-83 006 006 ,, (medium grain) 8915 , I-9I 001 889 006 0-14 ,, (large gra'n) .. 86 -08 239 001 II06 0-15 007 Florador 89-45 i-8o 001 867 008 OIO 67-40 2-52 03 9-42 OIO 018 1 Balland, Journ. de Pkarm. el de Chim., 1898, 6™ ser., vii. 328 ; Analyst, 1898, p. 178. a Battle Creek Sanitarium Company, Ltd., Michigan, U.S.A. Several other ingenious and useful cereal preparations are made by this company. 8 25, East Cumberland Street, Glasgow. * Analyses by Katherine I. Williams (Journ. Amer. Chem. Soc, 1907, xxix., No. 4). 220 FOOD AND DIETETICS' Shredded wheat 1 is a preparation of whole wheat in the form of shreds or flakes, which have been cooked to the consistence of a biscuit, and represents the whole grain in a very digestible form. Chapman's whole -wheat flour is described at p. 469. Force consists of malted whole wheat in the form of flakes, cooked with steam. It is easily digested, but not really of higher nutritive value than fine wheaten biscuits (see p. 207). The following is its composition : Water Proteid Soluble carbohydrates Insoluble ., Fat .. .. Mineral matter . . 9 28 per cent. 942 .. 11-36 ,, 65'69 ,. 135 .. 290 ,, Grape-Nuts is another malted preparation of the entire wheat berry, which requires no cooking. It contains a high proportion of soluble carbohydrates, as well as a considerable amount of proteid, as is shown by the following analysis : Water Proteid Soluble carbohydrates . Insoluble , , Fa Mineral matter . . 6'i8 per cent. "97 4272 3652 061 „ 200 ,. Roborat 2 and Glidine 3 are proteid preparations derived from wheat. In addition, they contain an appreciable amount of lecithin. As they are practically free from starch they are useful aids in the preparation of diabetic foods, and may be regarded as having much the same nutritive value and uses in the diet as casein pre- parations. Other Cereals : Oats. Oats may be regarded as the most nutritious of all cereals. They are rich in nitrogenous matter and mineral substances, and are peculiarly rich in fat, the only other cereal which can at all compare with them in that respect being maize. Starch is present to the extent of about 38 per cent. Further, of the total nitrogenous matter, 94 per cent, is in the form of proteid, and therefore available for tissue- building. Unfortunately, the husk of oats is closely adherent, and cannot be entirely separated from the kernel, so that 1 Shredded Wheat Company, St. George's House, Eastcheap, E.C. 3 Callard and Co. 3 Menley and James, Ltd. PATENT PREPARATION OF WHEAT 221 by the ordinary methods of grinding a good deal of cellulose is left in the meal in the form of small sharp particles. These act as stimulants to the intestine, and make oatmeal a valuable food where the intestinal movements are sluggish, but, on the other hand, are apt to prove rather irritating to some persons. Oatmeal is also found to be a ' heating ' food in the case of some individuals, and the development of skin eruptions sometimes follows its use. This ' heating ' effect is said not to be due to the large amount of proteid which it contains, but to a special constituent to which the name ' avenin ' has been given. 1 Similar ' stimulating ' results are often observed in horses which are liberally supplied with oats. It must be stated, however, that the existence of this substance is denied by many observers. Oatmeal is also one of the few vegetable foods which contain appreciable quantities of uric-acid formers (purin bodies). It is therefore well to forbid its use in some cases of gout. There are various ways of preparing oats for human food. It may be simply cleaned and ground, the result being oatmeal of various degrees of fineness, or the branny particles may be separated, and the ' oat flour ' alone used. Groats consist of oats from which the husk has been entirely removed ; when crushed, Embden groats results. Boiling has recently begun to be employed as a method of pre- paring oats, instead of grinding. The great pressure to which the grains are subjected between the rollers ruptures the cell walls, breaks down the cellulose, and flattens the grains out so that they are more easily softened by cooking. By the application of heat during the rolling process, the grains are at the same time partially cooked. This not only has the advantage of rendering subsequent preparation for the table considerably less laborious, but also alters the fat, which is so abundantly present in oats, in such a way that it is less liable to become rancid, so preserving the natural flavour of the grain. ' Quaker Oats ' is one of the best known of these preparations. 'Waverley Oats,' ' Provost Oats,' Carr's ' Oaten,' 'Creamota,' and Montgomerie's ' Berina ' are examples of Scottish rolled oats. ' Avenine ' is a similar product. The composition of some special preparations of oats is shown in the following table : 1 Sanson, Comptes Rendus, 1883, xcvi. 75. 222 FOOD AND DIETETICS PREPARATIONS OF OATS. Scottish Irish ' Quaker Carter's ' H-O.' Mont- gomerie's Scott's Oat Flour. Robin- Oatmeal. Oatmeal. Oats.' Oats. Fine Oatmeal. Groats. Water . . 50 5° 7-8 31 90 6-3 58 104 Proteid 146 134 M7 129 IV8 no 100 n'3 Fat .. IOI 88 62 62 8-s 68 5o 6'5 Carbo- 651 684) hydrates 698 760 672 742 779 704 Cellulose 3' 1 r?) Mineral matter 21 20 IS 1-8 17 17 13 17 The composition of some of these, when prepared ready for eating, is as follows : COMPOSITION OF ROLLED OATS WHEN COOKED. 1 Water. Proteid. Fat. Starch. Cellulose. Mineral Matter. Quaker Oats Provost Oats Mother's Oats .. 92-48 8844 8972 1-65 200 1-92 032 036 °'45 624 900 870 009 016 015 024 O 24 Ol8 It will be observed that the finer the product the poorer it is in nitrogenous and mineral matters. In this respect oat flour bears the same relation to oatmeal as fine wheat flour does to whole wheatmeal. 2 Veda Oatmeal 3 is a special preparation of oats in which much of the starch has been converted into soluble forms. It is thus more easily digested than ordinary oatmeal, and may agree with patients in whom the latter causes acidity. Plasmon Oatmeal is a combina- tion of plasmon and oatmeal, which contains 20 per cent, of proteid and 8 per cent, of fat. It is pre-cooked, and of very high nutritive value. Owing to the absence of gluten, oatmeal is unfitted for bread- making, and is usually simply mixed with water and made into cakes. By mixing fine oatmeal with an equal quantity of wheat flour, however, a fairly good loaf can be obtained. A given weight of oatcake (made without butter) contains rather more than twice as 1 Analyses by Katherine I. Williams (lourn. Amer. Chm. Soc, 1907, xxix., No. 4). 2 Cowan's ' special quality ' of Scotch oat flour is an excellent preparation for the making of gruels and as a food for children. 8 The Veda Food Company, 25, North Bridge, Edinburgh,, OATS 223 much building material as an equal quantity of bread, and has almost twice as great a fuel value. Oatmeal requires to be very thoroughly boiled in order to soften the cellulose which it contains. ' Brose,' which is made by merely stirring oatmeal into boiling water, is not a food for delicate stomachs. As regards the absorbability of oats, experiments show 1 that porridge made from rolled oats, even if taken in considerable quantities, is very well absorbed. Roughly speaking, 95 per cent, of its proteid, 93 per cent, of its fat, and 96 per cent, of its carbohydrates enter the blood, whilst 92 per cent, of the energy which it contains is ' avail- able ' in the body. This compares very favourably with the results yielded by bread. On purely chemical grounds, oats compare very favourably with wheat as a source of nutriment. A typical tsa and bread-and-butter meal (No. 1) may be contrasted with one of porridge and milk (No. 2) of the same cost (ijd.) thus 2 : No. 1. Ingredients. Proteid. Fat. Carbohydrates. Tea . . — — — Sugar (J ounce) .. — — 14-2 Milk (l| ounces) .. . . 1/2 I "4 l '7 Bread (10 ounces) .. .. 26-1 37 150-8 Butter (J ounce) .. .. 0-2 11-5 — Total 27-5 166 1667 No. 2. Oatmeal (8 ounces) .. 36-6 16-4 I53"4 Milk (10 ounces) .. .. 9/4 11-3 14-2 Total 460 277 167-6 The total energy value of the first meal is 950-6 Calories ; of the second, 1,133 Calories. The superiority of the porridge and milk meal as a source both of building material and of energy is very striking. Maize (Indian Corn). Maize is not so largely used as human food in Great Britain as it should be, but throughout America it forms a staple article of diet, while in Mexico and Natal maize is literally the ' staff of life ' (Letheby). It was introduced into Ireland at the time of the potato famine in 1848, and has since established a place for itself in the 1 Bulletin No. 101, United States Department of Agriculture, Office of Experi- ment Stations, p. 47, igoi. 2 ' A Study of the Diet of the Labouring Classes in Edinburgh,' p. 77 (Edin- burgh : Otto Schulze and Co.). 224 FOOD AND DIETETICS dietary of the people, so that Ireland now imports more of it for food purposes than any other European country. Chemical analysis (see Table, p. 188) shows that maize is quite as nutritious as wheat in all except its mineral ingredients, while it is richer in fat than any cereal except oats, containing twice as much of this important constituent as wheat or barley, and three times as much as rye. In nitrogenous matter it is slightly inferior to most other cereals, but fully 87 per cent, of this is in a proteid form. As regards its digestible carbohydrates, it is equal to wheat, but some- what inferior to barley or rye. Maize is prepared for food in many different ways. In Ireland it is made into a sort of porridge, called stirabout, or, in the more expressive phraseology of America, mush. In Northern Italy and the South Tyrol it is prepared in a similar way, but with the addition of cheese and other ingredients. Maizemeal is prepared by grinding after removal of the germ and husk. A yellow and a white meal are thus prepared, but there is no difference between them as far as nutritive value is concerned. Fine maizemeal is more gritty than wheat flour, but when mixed with the latter its presence can hardly be detected. The comparative cheapness of maize flour is an inducement to millers to adulterate wheat flour with it, and this is already being done to some extent in America and France. Flour so adulterated yields fewer loaves than an equal quantity of pure wheat flour, and the bread produced is moister than wheaten bread, and has a tendency to be sodden. An addition of 10 per cent, of maize flour is calculated to mean a reduction of five loaves on the sack. Owing to the absence of gluten, this meal cannot be used to make ordinary bread, but it is often baked into cakes of various sorts. The johnny (corruption of ' journey ') cakes of North America are unleavened, and are made of a rather coarse maizemeal. Similar cakes constitute the tortilla of South America. The following is the composition of johnny cakes I 1 Water . . . . . . . . . . 380 per cent. Proteid 8-g Fat 27 ,, Carbohydrates .. .. .. .. 47^3 „ Mineral matter .. .. .. .. 3 - 5 ,, On comparing this with the analysis of good white bread, given on p. 202, it will be seen that the comparison is all in favour of maize. Sometimes the maizemeal is leavened with yeast and subsequently baked in iron vessels. In this form it is known as pone, while in Ireland baking-powder is used, or the maizemeal is mixed with flour and then converted into loaves. One-third of its weight of good 1 Analysis by Atwater and Wood. MAIZE 225 flour is sufficient to enable fine maizemeal to form good loaves. The colour of the bread is always rather dark, however, even if the proportion of wheat flour used be increased to one- half. Various special preparations of maize deserve mention. Hominy, cerealine and samp are preparations of broken or split maize of various degrees of fineness. The composition of the first two is as follows : Hominy. 1 Cerealine? Water 1 1 9 per cent. 10 6 per cent. Proteid .. 82 9'4 Fat .. 06 I'O „ Carbohydrates .. 78-9 .. 786 „ Mineral matter . . .. 04 04 .. Both preparations are of high nutritive value and admirably adapted for making puddings, etc. Cornflour, maizena and oswego are prepared from maize by washing away the proteid and fat by means of dilute alkaline solutions, so that little but starch is left. Church states that cornflour contains only 18 grains of proteid in every pound, and a sample of Brown and Poison's cornflour which the writer examined showed a mere trace of nitrogen. The following is an analysis of maizena : 3 Water . . . . . . . . . . 14-3 per cent. Proteid . . . . . . . . . . o - 5 „ Carbohydrates . . . . . . . . 84 9 „ Mineral matter . . . . . . . . 03 „ These preparations must therefore be regarded simply as agreeable forms of starch, well adapted for food, provided they are taken along with some proteid and fat carrier, such as eggs or milk, but by no means to be recommended on economic grounds. A special small variety of maize is called in America pop-corn. When roasted it swells up and ultimately bursts. In this form it is known as 'popped pop-corn,' and is the basis of various sweets. Its composition is as follows : 4 Pop-corn Pop-corn {Raw). (Popped). Water . . io - 8 per cent. 4-3 per cent. Proteid 11-2 „ 107 „ Fat ■• •' 5'2 „ 5'° » Carbohydrates 71-4 „ 787 „ Mineral matter .. ..1-4 „ 1-3 „ It is thus a valuable food. Corn Flakes 5 consist of cooked maize which has been treated with malt-honey, dried, rolled and baked. It is a nutritious and digestible breakfast food. 1 Analysis by the author. 2 Analysis by Atwater and Wood. 8 Given by Klemperer in Leyden's ' Handbuch der Ernahrungstherapie,' p. 298. 4 Analysis by Atwater and Wood. 6 Battle Creek Sanitarium Company, Ltd. 15 226 FOOD AND DIETETICS Sugar-corn is a special variety of maize, containing much sugar. It is cooked while still green, and forms a sweet and succulent vegetable much esteemed in America. Maize is not only a highly nutritive cereal from the chemist's point of view, but has the further advantage of being very well digested in the human body. Experiments show that 90 per cent, of its dry matter is absorbed, as compared with 82 per cent, in the case of wheat. Of the proteid of maize, ig - 2 per cent, escapes absorption ; l in wheat about 20 per cent, is lost. Maize must undoubtedly be regarded as a food of great nutritive value. ' With a diet of Indian corn bread and pork,' says an American writer, 2 ' the workmen of this country are capable of enduring the greatest fatigue and performing the greatest amount of physical labour.' It is also an economical food. It has been calculated 3 that when maize and wheat are both selling at the same price per bushel one gets the same amount of digestible matter for a given sum in both. In wheat, however, one gets i\ pounds more proteid, and in maize i\ pounds more carbohydrate. The fuel value in each case is almost precisely the same. In view of these facts and of the approaching scarcity of wheat, one cannot help a feeling of regret that maize is not more widely adopted as food amongst the working classes of this country. ' The cry of Europe,' says C. J. Murphy, 4 ' is " cheap bread " ; it is a bitter, agonizing cry, and we may best respond to it by instructing the toiling masses of the Old World in the excellence and cheapness of maize, and the proper methods of preparing it.' Barley. Barley is chiefly characterized by its richness in mineral matter. It contains more fat than wheat, but is comparatively poor in proteid. The amount of starch in it varies in different samples from 39 to 57 per cent. (O'Sullivan). The whole grain when ground constitutes barleymeal. Scotch barley is the grain stripped of its 1 Rubner, Zcit. /. Biolog., 1879, xv. 115. See also experiments by Malfatti, quoted by Konig. 2 United States Department of Agriculture, Division of Chemistry, Bulletin 50, p. 11. 3 Ibid., p. 14. 4 ' Report to United States Department of Agriculture on the Use of Maize in Europe,' p. 6. BARLEY 227 husk and roughly ground. It is chiefly used as human food, however, in the form of either ' pearl ' or ' patent ' barley. The former consists of the whole grain polished after removal of the husk ; the latter is simply pearl barley ground into flour. The composition of these preparations is shown in the Table (p. 189), and the following is an analysis of Robinson's Patent Barley by Leeds : Moisture io- 10 per cent. Proteid 5' J 3 ,. Fat 0-97 ,, Carbohydrates .. .. .. .. 8187 ,, Mineral matter i"93 ,1 Barley contains but little gluten, in consequence of which its dough is too ' heavy ' to make good bread. When mixed with half its weight of good wheat flour, however, barleymeal can be con- verted into good enough loaves. Writing on the nutritive value of barley in 1872, Letheby said: * Barleymeal is the chief food of a large number of people in the North of Europe and in the South of England, where the labourer is partly paid his wages in meal or grain. It is also used in Wales and Scotland, especially in winter-time, when wheaten bread is dear, and to some extent in Ireland. It is employed by about 90 per cent, of the out-door labouring population of England. At the time of Charles I. (1626), according to M'Culloch, it was the usual food of the ordinary sort of people, and as late as the middle of the last century hardly any wheat was used in the Northern counties of England. In Cumberland the principal families used only a small quantity of wheaten bread about Christmas-time. The crust of the everlasting goose-pie, which adorned the table of every county family, was invariably made of barleymeal.' Since this was written barley has been steadily more and more displaced by wheat as an ordinary article of diet, and no doubt with considerable nutritive advantage. As an article of diet in the sick-room, bar'ey finds its chief use as the main ingredient of barley-water, a preparation which contains, however, but very little nutriment, as the following analysis by Wynter Blyth shows i 1 1 A series of analyses by Corlette {Australasian Med. Gazette, 1905, xxiv. 1 ) of barley-water prepared from two heaped teaspoonfuls of pearl barley to a pint of water showed that the average amount of starch in the product amounted to 2 03 per cent. 15—2 228 FOOD AND DIETETICS Fat 002 ,, Starch 0-39 Sugar Mineral matter 0-05 °"°3 .. It is chiefly of value on account of its demulcent properties. Rye. Next to wheat, rye is the great bread-making grain of the world. It contains less gluten than wheat, and the kind of gluten seems to be also chemically different, and as a result of this the bread derived from rye is apt to be rather moist and dense. An extreme example is the black bread, or pumpernickel, of North Germany. The composition of the different flours derived from rye varies very considerably with the fineness of milling ; but fine rye flour is much poorer in proteid than flour of a similar grade produced from wheat. 1 Fine rye bread is therefore poorer in building material than wheaten bread, but it is somewhat superior in this respect to bread made from maize. The digestibility of fine rye bread is about equal to that of good wheaten bread ; but the coarser varieties, especially pumpernickel, are very wasteful foods, 32 per cent, of the proteid even in moderately fine rye bread being lost, as compared with 20 per cent. in white bread. In the case of pumpernickel the loss rises to 42 per cent. Rice. Rice is the poorest of all cereals in proteid, fat and mineral matter. On the other hand, it has fully 76 per cent, of starch. The starch has the further advantage of being present in small and easily- digested grains. When boiled, rice swells up and absorbs nearly five times its weight of water, while some of its mineral constituents are lost by solution. It is preferable, therefore, to cook it by steam- ing. Boiled rice has the following composition : 2 Water 527 percent. Proteid . . . . . . . . . . . . 5*0 „ Fat 01 „ Carbohydrates . . . . . . . . 41 -g „ Mineral matter .. .. .. .. 03 „ 1 Vide Falke, Archiv f. Hygiene, 1897, xxviii. 49, and Romberg, ibid., i897,xxviii, 244. 2 Analysis by Atwater and Woods. RICE 229 Rice is only moderately easy of digestion in the stomach, 2 J ounces cooked by boiling (i.e., about two-thirds of a full soup-plateful) requiring three and a half hours for its disposal. This is probably to be attributed to the fact that it is not the function of the stomach to digest carbohydrates. On the other hand, rice is absorbed with very great completeness in the intestine ; indeed, its solid constituents enter the blood almost as completely as those of meat. This is to be attributed to the comparative absence of cellulose. Practically none of the starch is lost, but the waste of proteid amounts to 19 per cent. 1 It follows from this that rice is one of the foods which leave the smallest residue in the intestine, and this gives it a considerable value in some cases of disease. The nutritive value of rice is much impaired by its poverty in proteid and fat. Hence it is not adapted to be an exclusive diet, but should be eaten along with other substances rich in these two elements, such as eggs, cheese, or milk. 2 Even as regards carbo- hydrate it would require about 1 pound 3 ounces of rice to furnish the daily need of an active man. This would entail the consumption of about 5 pounds of cooked rice daily. 3 Millet and Buckwheat. These cereals* are not used as human food in this country, although they are by no means of low nutritive value, but stand midway in that respect between wheat on the one hand and rice on the other. Millet is freely consumed in Africa, being the staple diet of the negroes of the Upper Nile, and in some Southern European countries, while in China it is used to make bread. The dhoora (sorgho-grass), or Indian millet, is of very similar composition. The following is an analysis of it given by Professor Church : Water 122 per cent. Proteid • 82 Fat ■ 4'2 Carbohydrates ■ 7°'6 .. Cellulose • 31 Mineral matter ■ 17 .. * See Kumagawa, Virchow's Archiv, 1889, cxvi. 370. a It is interesting to note that in countries in which rice is largely used as a daily food this is actually done, as in the Italian Risotto, the Turkish Pilaff, and the Spanish ' Polio con Riz. ' 3 It is worth observing, too, that in Eastern countries in which rice takes the place of bread it is eaten in a much drier, and therefore more concentrated, form than it is in Europe, and with the addition of various sauces and condiments to give it flavour and promote its digestion. 4 Buckwheat is not strictly a cereal, but belongs to the Polygonaceae. It is considered here for convenience. 230 FOOD AMD DIETETICS Buckwheat is about equal in nutritive value to millet, but contains much more cellulose (10 per cent.). It is usually eaten in the form of a porridge. In this country it is hardly ever used as human food, but it is freely consumed in Brittany and Holland, and in some parts of the United States. The published analyses of buckwheat are somewhat discordant. Church x gives the following as the composition of the grain when deprived of its husk : Water 13-4 per cent. Proteid .. .. .. .. .. 152 „ Starch 636 ,, Fat 34 „ Cellulose .. .. .. .. .. 2'i „ Mineral mailer .. .. .. .. 23 ,, Another analysis 2 of buckwheat-flour was as follows: Water . . . . . . . . . . 14 -2 per cent. Proteid .. .. .. .. .. 9/2 ,, Carbohydrates .. .. .. •• 73'3 >t Fat i-8 „ Cellulose .. .. .. .. .. o'8 ,, Mineral matter . . . . . . . . 1 '2 , , 1 ' Food': London, 1898 (Chapman and Hall), p. 93. 2 Leyden's ' Handbuch der Ernahrungs Therapie," 2nd edition, 1903, i. 99. [2 3 I ] CHAPTER XIII THE PULSES— ROOTS AND TUBERS The Pulses. In this group are included peas, beans, and lentils, and their allies. The edible parts of these resemble the grain of cereals in that they are to be regarded as storehouses of nourishment for the young plant. The chief chemical characteristic of the group is the richness of its members in nitrogen, in virtue of which fact they have been described as ' the poor man's beef.' All but from 3 to 5 per cent, of the total nitrogen, moreover, is in the form of proteid (Church). Why the young pulse should require so much more nitrogen than the young cereal, it would be difficult to say, but perhaps it is on account of its greater rapidity of growth. It may be remembered that there is a special provision for the adequate supply of nitrogen to plants of this group in the form of little nodules on their roots, which nodules consist of masses of bacteria, possessed of the remarkable power of fixing the free nitrogen of the atmosphere and passing it on for the use of the plant. The chief proteid found in the pulses is called legumin, 1 also spoken of sometimes as vegetable casein, owing to its close resemblance to the principal proteid of milk. So much is this the case, that a kind of cheese may actually be prepared from beans. Legumin is able to unite with salts of lime, and the resulting com- pound is not soluble in water. It is for this reason that peas and other pulses do not readily soften if the water in which they are soaked contains much lime, *.«., is hard. The addition of a little bicarbonate of soda to the water throws down the lime. Hence the importance of adding soda to hard water in which pulses are to be soaked. 2 Magnesia, which resembles lime in so many other respects, has no effect upon legumin. 3 The proteids of some of the pulses seem to be especially rich in sulphur, and this, by giving rise to sulphuretted hydrogen gas, helps to explain their tendency to produce flatulence. Beans are richer in 1 A nucleo-albumin (Maly's Jahres-Bericht Thier-Chemie, 1897, xxvii. 21). a Richter has shown (Archiv f. Hygiene, 1903, xlvi. 264) that peas are not so well digested and absorbed when boiled in hard water as they are when cooked in soft, 3 See S^umpe!!, Dent. Archiv f. Klin. Med., 1876, xvii. 108. 232 FOOD AND DIETETICS sulphur than peas, while lentils contain least of all. The ash of the pulses is poorer in phosphorus than that of the cereals, but richer in potash and lime. The pulses, indeed, contain more of the latter ingredient than any other form of vegetable food. The pulses are well supplied with carbohydrates, but are poor in fat. For this reason they go well with fatty foods (e.g., bacon and beans, pork and pease pudding), and are improved by being served with sauces containing butter, or cooked with oil. They also contain a bitter principle which renders then unpalatable to many persons. It should be added that they contain considerable quantities of purin-bodies, in consequence of which the excretion of uric acid is greater after their use. For this reason they are sometimes forbidden to the gouty. Dried peas and beans require prolonged soaking in order to soften their skins. Even haricots, in which the skin is com- paratively thin, require about eight hours to soften. The water in which they are soaked should be soft or boiled. The reason for this was given above. The soaking is inevitably accompanied by some loss of proteid and mineral matter, and also of carbohydrates ; but it has the advantage of removing most of the bitter principle in the seeds. The amount of water taken up is very great. The propor- tion of water in dried haricot beans, for example, rises as the result of soaking and boiling from 14 per cent, up to 73 per cent., and in the case of peas the increase is from 9-7 up to 86-9 per cent. 1 This increase in water means, of course, a corresponding increase in the weight and bulk of the food, and must always be taken into account when comparing the relative nutritive values of the pulses and meat. The pulses are not readily digested by the stomach. As Galen said: 'They are harder to digest than other foods and give bad dreams.' This is no doubt partly owing to their bulkiness when cooked. Thus, 5^ ounces (150 grammes) of lentils in the form of a mash, or about a soup-plateful, remained in the stomach for four hours, and 200 grammes of peas in a similar form for four hours and a quarter. An equal weight of French beans (haricots verts) remained rather longer even than that. If properly prepared, the pulses are absorbed in the intestine very thoroughly. Thus the proteid of pea or lentil flour is all taken up except about 8 or 9 per cent. 2 when 200 grammes (7 ounces) are given daily. Even when the amount given was as much as 600 grammes (21 J ounces) the loss was only as follows : 3 1 Analyses by Katherine J. Williams, Journ. o/Chem. Soc, 1892, lxi. 226. 2 Striimpell, Deut. Archiv /. Klin. Med., 1876, xvii. 108. 8 Rubner, Zeit. f. Biolog., 1880, xvi. 119. THE PULSES 233 Dry substance .. .. .. .. g - i per cent. Proteid .. .. 17-5 „ Carbohydrate .. .. .. .. 36 ,, Mineral matter .. .. .. ..32-5 This shows that the proteid of the pulses, if given in a state ol fine division, is capable of very good absorption — almost as good, indeed, as that of gluten when given in the form of macaroni, in which the loss is n - 2 per cent., and considerably better than gluten when taken in the form of white bread (loss about 20 per cent.). On the other hand, the loss is very much greater if the food is not given in a state of fine division. It was found, for example, that if the lentils were simply boiled soft and taken along with broth, the loss of proteid rose to 40 per cent. 1 It will be noted that there was a small loss of carbohydrate even on pea flour. The amount of it, however, is less than in the case of potatoes or carrots, but in white bread, it will be remembered, there is no loss of carbohydrate at all. Some extensive investigations on the absorption of different forms of legumes have been made in recent years in America. 2 They showed an average absorption of 80 per cent, of the proteid and 97 per cent, of the carbohydrates. These results are very favourable when it is remembered that the legumes constituted the major part of the diet in the subjects studied. The nutritive value of the pulses is undoubtedly high. Especially is this the case if they be regarded as sources of proteid. It would require about 600 grammes (i£ pounds) of pea flour to supply the amount of proteid required daily by an active man. Suppose this were to be given in the form of pea soup. A good thick soup would contain 25 grammes — a heaped tablespoonful — in each plate. The proteid value of this would be equal to an ounce of meat. Twenty- four platefuls of such a soup, then, would require to be taken in the day. By making the soup with milk instead of water — an excellent plan — the amount of pr6teid in it would be trebled, and eight platefuls would suffice. The 600 grammes of pea flour would hardly, however, contain as much carbohydrate as is required, and would be very deficient in fat. These deficiencies would require to be made good by the addition of some other articles to the diet, or by increasing the amount of pea flour consumed. As a matter of fact, it has been found that when the quantity of peas eaten amounts to 960 grammes (34^ ounces) in the twenty-four hours, all the demands of nutrition are 1 Strumpell, Deut. Anhiv f. Klin. Med., 1876, xvii. 108. s Studies on the Digestibility and Nutritive Value of Legumes (United States Department of Agriculture, Office of Experiment Stations, Bulletin 187, 1907). ^34 FOOD AND DIETETICS satisfied i 1 but it is very doubtful whether anyone could go on con- suming this quantity for any length of time. It comes then to this, that, while the pulses are most valuable sources of proteid, they are not adapted to be the exclusive diet of health. As a cheap and efficient method of supplementing the deficiency of nitrogen in a purely vegetable diet, however, their use is strongly to be recom- mended, and it is a pity that they are not more largely taken advan- tage of by those to whom economy is of importance, for unquestionably the pulses are amongst the cheapest of foods, and a given sum will yield more proteid, if invested in them, than in any other way (see Plate III.). It remains to add a few words about the individual members of the pulse group. Their chemical composition is shown in the following tables : COMPOSITION OF PULSES. (The Means of Many Analyses.) Water. Proteid. Carbo- hydrates. Fat. Cellu- lose. Mineral Matter. Green peas . . 78-1 4-0 160 0'5 OS 0-9 Dried ,, 13 O 21 "O 55 - 4 1-8 60 26 Prepared pea flour IO'2I 2798 5693 1 97 042 249 II'7 23-2 584 20 20 27 Horse beans (dry) 13 I 255 5°'9 i'7 55 33 Broad or Windsor beans (dry) 84 26-4 586 20 i-o 36 French beans (haricots verts) 895 15 73 04 06 07 Haricots (haricots blancs) 117 230 558 2'3 40 32 Scarlet runners (stewed) 91-12 1 7 37 03 29 o"3 Soy beans no 329 287 181 4'4 49 ,, bean flour 93 395 282 137 4-0 53 Peanuts 83 240 170 443 45 1-9 Butter beans (ground unpeeled) 105 20'6 626 2-0 — 43 The following represents some recent analyses of dried pulses by Balland. 2 Beans (Haricots). Mini- Maxi- Mini- Maxi- Mini- Maxi- mum. mum. mum. mum. mum. mum. Water IOOO 20-40 1170 1350 io-6o 1420 Proteid I3-8I 2516 2032 2424 1888 2348 098 246 058 1-45 I'22 I 40 Starch and sugar . . 5291 6098 5607 6245 56'2I 61 -IO Cellulose 2-46 462 2 96 3 - 56 2 90 5-52 238 4-20 199 2-66 226 35° 1 Rubner, loc. cit. 2 Compt. Rend., 1897, cxxv. 119. COMPOSITION OF THE PULSES 235 The garden pea (Pisum sativum) is eaten either fresh (green peas) or dried. Green peas cooked in the usual way contain from 12 to 16 per cent, of carbohydrate, of which a considerable proportion is sugar. Of beans there are several edible varieties. The French or kidney bean (Pkaseolus vulgaris) is eaten either in the young state along with the pod (haricots verts), or the seeds are consumed alone either fresh or after drying (haricots blancs). The amount of cellulose in the pod causes it to be digested and absorbed with difficulty, and on that account it is a wasteful form of food. Allied to the French bean is the scarlet runner (Pkaseolus multiflorus), which when stewed constitutes ' Turkish beans.' The broad or Windsor bean (Faba vulgaris) is eaten either in the fresh or dry state. A coarser variety of the same plant is the horse or field bean. It is not usually consumed as human food. Beans are on the whole richer in proteid than peas, but contain also more sulphur, and are more apt to cause flatulence. The Lentil (Lens esculenta) is even richer in proteid than either the pea or the bean, and, as a rule, the smaller varieties of it are richer in that constituent than the larger. Egyptian lentils are amongst the best. Lentils contain little sulphur, and are more digestible and less apt to cause flatulence than either peas or beans. The ash of the Egyptian lentil is particularly rich in iron. The patent preparation known as Revalenta Arabica consists mainly of lentil flour. The following is the result of an analysis which I recently made of it : REVALENTA ARABICA; Moisture 91 per cent Proteid 22-0 „ Fat 15 Carbohydrates .. 652 „ Mineral matter .. .. .. .. 22 ,, It is really poorer in nitrogen than pure lentil flour. The latter costs 2^d. per pound ; Revalenta, 3s. 6d. It certainly in no way merits the very high claims sometimes advanced for it. A soup- plateful of Revalenta made from three moderately-heaped table- spoonfuls (60 grammes) yields thirty-six Calories less than a similar quantity of good porridge, but is slightly richer in proteid and mineral matter. In other words, it is rather more valuable as a tissue-builder than porridge, but is not so good as a source of heat or energy. It must be remembered, too, that it is considerably more expensive. The Soy Bean (Glycine Hspida) is the richest of all the pulses in 236 FOOD AND DIETETICS proteid, and has also a large amount of fat, but very little starch. For this reason it is of use as a bread substitute in diabetes, a flour being prepared from it and made into loaves or biscuits. In China and Japan it is extensively eaten in the form of soy cheese, and as various sauces and pastes, all of which are rich in proteid and so are fitted to supplement the deficiencies of rice. It is also grown in Southern Europe. The Peanut (Arachis hypogaa), although botanically one of the pulses, really resembles more closely the true nuts. Like these, it is rich in proteids and fat, and may be used as a diabetic food. It enters into the composition of the patent food known as ' Nutrose,' and after expression of the oil it forms cakes for cattle. Boots and Tubers. We have already seen that the chief bulk of the grain of cereals is to be regarded as a storehouse of nutriment for the use of the young plant. The roots and tubers, the consideration of which will occupy our attention in this section, may be regarded in like manner as reserves of nourishment for the use of the adult plant itself. During the prosperous days of spring and early summer the plant lays by of its superfluity against the certain adversity of autumn. The reserve nutriment so laid up is almost entirely in the form of carbo- hydrates — chiefly starch. Proteid and fat are scarcely represented at all. Hence it is obvious that in using the roots and tubers as foods we are tapping a supply of only one of our nutritive elements, and that fact must never be lost sight of in estimating the value of this class of vegetable foods. It remains to be added that, of the small proportion of nitrogenous matter which these foods contain, only part, and that not infre- quently a very small part, is present in the form of proteid. On the other hand, they are by no means destitute of mineral ingredi- ents, mainly salts of potash, and the presence of these confers upon the roots and tubers a greater value as articles of diet than they would otherwise be entitled to possess. As far back as the year 1781, Letheby tells us, Sir Gilbert Blane, in his work on ' Diseases of the Fleet,' alluded to the beneficial action of the potato in scurvy ; and the late Dr. Baly remarked, in his inquiries into the diseases of prisoners, that wherever potatoes were used scurvy was unknown. Another general consideration which must be borne in mind is that the mere cooking of these foods robs them of a very large ROOTS AND TUBERS 237 proportion of their mineral ingredients and of some of the nitro- genous matter in which they are already so deficient. For this reason the water in which they are cooked should also be utilized as far as possible, or, which is preferable, they should be cooked by means of steam. AVERAGE COMPOSITION OF EDIBLE PORTION OF ROOTS AND TUBERS. Water. Proteid. Carbo- hydrate. Fat. Fibre. Ash. Extrac- tives. Potatoes 78-3 2-2 l8'0 o'l 0-4 I/O I '4 Carrots 857 OS (Albu- minoid N X625) IOI 03 IS 09 10 „ (cooked) . . 93 4 o-53 339 017 18 014 Turnips 903 09 5'o OI5 18 0-8 I'l (cooked) 97'25 032 065 006 1 -a 032 Radishes 908 i'4 4-6 01 — 07 Beetroots 83 9 05 no (10 per cent, of sugar) 01 30 09 I'O ,, (cooked) 948 044 283 006 1-3 o'3 Parsnips 801 14 141 10 21 1-3 „ (cooked) . . 9728 022 1 46 029 072 012 Artichokes 798 23 145 03 20 10 (cooked) . . 91 6 18 46 008 09 061 891 1-6 6'3 03 20 o-6 Sweet potatoes 729 16 225 0'5 18 07 796 2-2 153 0'5 09 IS As regards the digestibility of these foods as a class, it may be said that it depends largely on the amount of cellulose which each happens to contain, but it is true of all of them that they are only indifferently absorbed, and are prone, by reason of their bulk, to derange the stomach and bowels if eaten in large quantity. We may now pass to a detailed examination of the chief members of the group, beginning with the potato. Potatoes. The potato was introduced into this country about 300 years ago, 1 and since that time it has steadily increased in popular favour, until it may now be regarded as one of the most important staple articles of diet. 1 A full account of the history of the discovery of the potato will be found in Weyl's ' Handbuch der Hygiene,' iii. 257. 238 FOOD AND DIETETICS If one cuts a raw potato across with a sharp knife and looks at the cut surface, three distinct layers can easily be made out (Fig. 1 8). These are (i) the thin outer skin. (2) A broader layer inside the skin called the ' fibro- vascular layer.' It con- tains a small amount of pigment, and turns green when exposed to the light, giving the potato an unpleasant taste. (3) The flesh of the potato, which makes up the rest of its bulk. On more care- ful inspection this is seen to be divided into a central core and an outer zone which surrounds it. These different layers form the following proportions of the whole potato : Fig. 18. — Cross Section of a Potato. a, Skin ; b, Fibro-vascular layer ; c. Outer zone of flesh ; d, Central core. 1. Outer rind . . 2. Fibro-vascular layer 3. Flesh .. = i\ per cent. = 89 The importance of recognising them is due to the fact that they differ considerably in chemical composition, as is shown in the following table :* COMPOSITION OF A POTATO. Water. Outer rind .. .. 801 Fibro-vascular layer 83 2 Flesh 8i-i Whole potato .. 813 The fibro-vascular layer is seen to be considerably richer in mineral matter and proteid than the flesh, and in peeling it off with the rind we lose these valuable ingredients. If the flesh of the potato is squeezed it can be separated into a solid part and a juice. The former consists mainly of starch ; it has only 15 per cent, of the nitrogenous matter. The juice consists of 1 See Bull. 43, United States Department of Agriculture, Office of Experiment Stations, Washington, 1897. Nitrogen. p£m. T ° tal - Fat. 025 043 o-8 024 , 0-36 O'l 018 tl'32 01 019 032 01 Carbo- Mineral hydrate. Matter. 146 18 I3'3 II 160 o-8 I5'7 09 THE COOKING OF POTATOES 239 water holding in solution nitrogenous matter and salts. It contains fully 85 per cent, of the total amount of nitrogenous matter con- tained in the potato. It must be clearly realized that by no means all of this nitro- genous matter is present in the form of proteid. Of the total amount of nitrogen in a potato, only 49 per cent, is contained in proteids, the remainder being in the form of ammonia compounds (amides, e.g., asparagin) and salts. The failure to recognise this fact has led people to assume that the whole of the nitrogen of the potato represents proteid, and so greatly to overrate the value of potatoes as tissue-building food. The richer the potato is in proteid — in other words, the juicier it is — the more ' waxy ' is it when cooked, for the coagulated proteid holds together. For this reason young potatoes, which contain more juice than those which are older and more starchy, have a more solid and waxy consistence when cooked than the latter. The richness of the potato in starch is its most striking chemical characteristic, and causes it to be one of the chief commercial sources of that substance. Dextrin and ' British arrowroot ' and many other things are prepared from it. The starch grain of the potato is of specially large size, and seems to be more easily attacked by ferments than most forms of starch, probably because it does not contain much « starch cellulose.' Owing to their readiness to undergo fermentation potatoes should be avoided in some diseased conditions, such as dilatation of the stomach. The most important mineral ingredients of potatoes are salts of potash, and, potatoes are one of the chief sources from which we obtain our supply of these salts. Part of the potash is united with citric acid. Potatoes, like all tubers, may have their composition, and consequently their nutritive value, profoundly modified by the mode in which they are cooked. The chief danger is that their nitrogenous constituents and mineral salts may be dissolved out. The amount of starch and water which they contain is scarcely ever affected. 1 These facts are brought out in the following analyses : 2 1 See analyses of cooked potatoes by Katherine Williams, Journ. of Chem. Soc, 1892, lxi. 226. 2 United States Department of Agriculture, Office of Experiment Stations, Bull. 43, p. 30. 640 POOH AMD METRICS THE LOSS OF MATERIAL DURING THE PROCESS OF COOKING POTATOES. Dry Matter. Nitrogen. Carbo- hydrates. Proteid. Non- Proteid. Total. Ash. Skins removed before Boiling. Water cold at beginning Water hot at beginning Per cent. 37 40 Per cent. 43 3 3 Per cent. I2'9 179 Per cent. 83 100 Per cent. z-5 28 Per cent. 170 I7-4 Average 39 3-8 I5-4 92 27 172 Boiled with Skins on. Water cold at beginning of test Water hot at beginning o'3 03 06 04 06 17 06 i-o 02 01 19 I'2 Average 03 05 i'i o-8 0'2 16 WATER. 783% The kind of water in which they are soaked does not make any differ- ence. It has been calcu- lated that if a bushel of potatoes were peeled and soaked before being boiled the loss of nutrients would be nearly equivalent to the amount contained in 1 pound of beefsteak. It follows from this that potatoes should either be steamed or cooked in their 'jackets.' The accompanying dia- gram shows the per- centage composition of a potato, and the loss of nutrients which it sustains Fig. i 9 . — Percentage Composition of a 1 Potato and loss of each Constituent on when cooked by the usual Boiling. method. THE COOKING OF POTATOES 241 The composition of raw and cooked potatoes from the average of many American analyses is as follows i 1 Refuse. Water. Pro- teid. Fat. Carbohydrates. Ash. Kind of Food. Sugar, Starch, etc. Crude Fibre. Fuel Value per Pound. Per Per Per Per Per Per Per Calories. 310 Potato, as purchased . . cent. 20 - cent. 626 cent. 1-8 cent. OI cent 138 cent. 09 cent. o-8 Potato, edible portion . . Potato, boiled Potato, mashed and — 783 75 '5 22 25 O'l - I 18-0 20-3 0-4 06 10 I/O 375 440 seasoned Potatoes fried in fat, — 75 'i 2-6 30 178 I i-5 5°5 ' ' Potato chips " Potato, evaporated White bread — 2 - 2 7-1 35 '3 6-8 8-5 9-2 39-8 °'4 1 "3 467 809 526 I 0-5 4'5 31 ■ I'l 2,675 1,680 1,215 The digestibility of potatoes in the mouth and stomach depends largely on the form in which they are eaten. They are less digestible when eaten as lumps than in a puree ; and ' mealy ' potatoes are more digestible than ' waxy.' Two medium-sized potatoes (weighing together 5J ounces) when boiled and eaten in the usual way remain for about two to two and a half hours in the stomach — that is, a shorter time than a similar weight of bread. In the intestine potatoes are, on the whole, very well absorbed. This is owing to the fact that they contain much starch and little cellulose. Even when the quantity consumed daily amounts to 3^- pounds, 92^ per cent, of the starch and 70 per cent, of the total nitrogen enters the blood. Potatoes are, however, by no means suited to constitute the sole, or even the staple, diet of man. They are much too bulky, and contain too little proteid in proportion to their starch. Thus, it would require about 22 pounds of potatoes to yield even 118 grammes of proteid daily, while this quantity would contain more than four times as much carbohydrate as one really needs. As a matter of fact, however, Rubner has found that 6J pounds of potatoes are enough to furnish 3,000 Calories of energy and to prevent any loss of bodily proteid. This is probably to be explained by the relatively enormous quantity of carbohydrates (».«., proteid-sparers) which such a diet contains. An experiment mentioned by Pereira 2 illustrates this fact very well. In the year 1840 some experiments with a potato diet were 1 United States Department of Agriculture, Farmers' Bulletin 295, 1907. 8 ' Food and Diet,' p. 372. 16 242 FOOD AND DIETETICS made in a prison at Glasgow. Ten of the prisoners, consisting of young men and boys, were put on a diet of 6 pounds of potatoes daily. At the end of the experiment (the duration of which is not stated) the majority of the subjects had gained considerably in weight, and all expressed themselves as quite satisfied with the potatoes, and regretted the change back to ordinary fare. It must be added, however, that these prisoners were only engaged in light work, and the state of their nitrogen balance was not investigated. Even granting that 6 pounds of potatoes per day is sufficient to supply fully all the needs of the body, it must be evident that this quantity is still unduly bulky, weighing as it does about twice as much as an ordinary mixed diet. The result of its continued use would be an undue burdening of the stomach and bowels, cul- minating in dilatation, if not disease, of these organs. The so-called ' potato belly ' of the Irish peasant is an example of such a result. It must also be borne in mind, in estimating the nutritive value of potatoes, that much of their nitrogen is in the form of substances which do not belong to the proteid group. Of these substances asparagin 1 is one of the chief. It contains 21 # 2 per cent, of nitrogen. Now, the direct nutritive value of asparagin is nil, but there is reason to believe that it plays a useful part in the intestine by limiting putrefaction, and so sparing proteids from destruction. It may also promote the absorption of proteids and carbohydrates into the blood. In the case of herbivorous animals these functions may be useful, but in carnivora and mixed feeders, which eat plenty of proteid, they are superfluous. 2 As regards economic value, potatoes must be regarded as a cheap, but by no means the cheapest, kind of food. Thus, when potatoes are selling at id. and bread at i£d per pound the former are two or three times dearer than the latter. 3 From the point of view of national economy, however, potatoes are undoubtedly a cheap food. Thus, Boussingault found that a given piece of land produces : Wheat. Rye. Peas. Potatoes. Proteid 510 440 560 950 Starch .. 1.590 1,196 780 6,840 Ash .. 90 62 60 323 Allied to the potato, though not now eaten in this country, are the sweet potato and the yam. 1 Asparagin = amido-succinamic acid. 2 See Kellner, Maly's Jahres-Bericht Thier-Chemie, 1897, xxvii. ?2i, and Gabriel, Zeit. f. Biolog., 1892, xxix. 115 ; also Kbnig, ' Nahrungfmiitei Chemie,' Bd. 1, p. 119, and F. Voit, ' Ergebnisse der Physiologie,' I., Abth. ±, 1902. 8 Smith, ' Foods,' p. 200. THE TURNIP 243 The Sweet Potato (batatas) is cultivated in hot countries, and is largely eaten in the United States. It used to be eaten in England before the present potato was introduced, and it is to it that Shake- speare refers when he makes Falstaff say, ' Let the sky rain potatoes !' The Yam is the tuber of a tropical climbing plant and is much larger than the potato, but resembles it in taste. The composition of the sweet potato and yam is represented in the table on p. 237. They are fully equal to the ordinary potato in nutritive value. WATER 90 3% ^ r ~ -^ N, PROTEID 0-9 Y. J XCABBOHYDRATE 5 Q'/y/ X. EXTRACT \5fS \FIBREI-8y^ LOSS Fig. 20. — Percentage Composition of a Turnip. Fig. 21. — Percentage Com- position of a Carrot, and Loss of each Nutritive Constituent by Boiling The Turnip. The chemical composition of a turnip is graphically represented in Fig. 20. It is difficult to realize that an apparently solid object like a turnip really contains more water than a fluid like milk ; yet such is the fact. A turnip contains almost no proteid, most of its nitrogen being in a non-albuminoid form. Carbohydrates are more abundantly represented than any other nutritive ingredient, but even they only amount to 5 per cent. Curiously enough, none of this is in the form of starch, that substance being left out in the turnip's composition. 16 — 2 244 FOOD AND DIETETICS ' Pectose ' bodies make up the bulk of the carbohydrate present. The nutritive value of these has already been discussed (p. 163), Seeing that starch and sugar are absent, there seems to be no reason why turnips should be forbidden to diabetics. A consideration of the above facts shows that the turnip can never be regarded as an important form of food, a conclusion which is accentuated by the fact that the white turnip eaten at the table, though finer in flavour, is of even less nutritive value than the coarser ' swede.' Carrots are decidedly more nutritious than turnips, mainly owing to their richness in sugar, of which they contain nearly 10 per cent, either as cane or fruit sugar. The amount of proteid which they possess is a negligible quantity, but their mineral salts are of some value. The composition of a carrot, and the loss of nutrients which it sustains on boiling, are represented in Fig. 21. It has been found 1 that the following is the loss of nutrients from the intestine on a diet of carrots and fat : Total solids lost .. .. .. =207 per cent. „ nitrogen lost .. .. .. =390 „ „ carbohydrates lost .. .. =182 ,, „ mineral constituents .. .. =338 „ Carrots cannot, therefore, be regarded as at all a digestible form of food. Nor are they easily disposed of by the stomach, for 5J ounces remain there for three hours and twenty minutes. Compared with the turnip and carrot, a raw Beetroot is a com- paratively valuable source of food. Here, again, this is owing to the fact that it contains a large amount of cane-sugar. The ordinary garden beet contains nearly as much sugar as the ' sugar beet,' and by special cultivation the latter can be made to contain 15 per cent, of cane-sugar. In the process of cooking, however, much sugar is lost, so that ordinary beetroot as it comes to the table does not contain more than 3 per cent. Like the carrot and turnip, the beetroot is of almost no value as a source of proteid. It contains altogether less than 2 per cent, of nitrogenous matter, and even of this only a fraction is in a proteid form. The exact proportions are : 35 per cent, of total nitrogen . . = proteid. 39 ,, ,, ., .. =amides. 36 ,, ,, ,, .. = ammonia salts and nitrates. The beetroot is also richer in cellulose than most tubers. The addition of vinegar to slices of beetroot helps to soften the latter, 1 Rubner, Zeit.j. Biolog., 1879, xv. 115. tapioca, sago and aukowroot h$ While it does not interfere with the digestion of the other carbo- hydrates, seeing that these are already in the form of sugar. Parsnips belong to the same order as the carrot. In the raw state they are fairly rich in starch and sugar, but lose much of the latter in the process of cooking. Jerusalem artichokes resemble turnips in containing no starch, but are fairly rich in carbohydrates belonging to the gummy series, which make them very mucilaginous when boiled. They also contain a little sugar and about 2 per cent, of the peculiar carbo- hydrate inulin, the nutritive value of which is unknown. It is certainly better borne by diabetics than other forms of carbohydrate, and may be allowed in mild cases (Von Noorden). About half of the nitrogen artichokes contain is in a non-proteid form. Onions are chiefly valued for their pungent oil, which makes them useful flavouring agents. They are thus to be regarded as condi- ments rather than foods. The large Spanish onion, however, is richer in nutrients, and may rank as a food. Onions are valuable in cases of constipation, probably owing to their richness in cellulose. Tapioca, Sago and Arrowroot. These are to be regarded simply as special forms of starch. Tapioca is derived from the roots of South American cassava plants belonging to the Sparge order (Euphorbiaceae). Curiously enough, one of these — the bitter cassava {Manihot utilissima) — contains, mixed up with the starch, a milky juice in which is present a good deal of that dangerous poison prussic acid. In preparing tapioca the juice is washed away from the grated root and the starch allowed to settle. It is then collected and dried on hot metal plates. The process of drying has the effect of rupturing most of the starch grains. Tapioca as found in the market contains about 1 1 J per cent, of water and 87J per cent, of starch, along with traces of proteid and mineral matter, and has a fuel value of 1,650 Calories per pound. Pure starch contains only 2 per cent, of water, and a pound of it furnishes 1,825 Calories* so that weight for weight pure starch is considerably more nourishing than tapioca. Tapioca remains a considerable time in the stomach. Forty grammes of it in the form of a thick gruel (about a soup-plateful) had not entirely left the stomach until after the lapse of two hours and forty minutes (Penzoldt). Its use should, therefore, be avoided in cases in which it is desirable to lighten the labours of the stomach. Experiments upon the absorption of tapioca in the intestine have 246 FOOD AND DIETETICS not been performed, but consisting as it does of starch alone, one would expect it to be absorbed very completely. Sago is derived from the pith of the sago palm. The trees are felled, split, and the starch washed out. It is then dried, and con- verted into pearl sago by granulating. One tree should yield about 500 pounds of sago. Commercial sago contains 867 per cent, of starch. Arrowroot is obtained from the rhizome of a West Indian plant (Maranta anmdinacea). The roots are mashed up, mixed with water, and the starch allowed to settle. When dried, it constitutes ordinary arrowroot. The superiority of Bermuda arrowroot to the other varieties is due to greater care in manufacture. The starch, having been washed away from the mashed roots and strained through muslin, is allowed to settle, and is subsequently dried in flat copper pans covered with gauze. When dry, it is packed by means of German-silver shovels into new barrels lined with paper stuck in with arrowroot paste. All these precautions are necessary to prevent the arrowroot from becoming contaminated, as it is so apt to be, by foreign flavours. For a similar reason it is exported on deck under covers, lest it may be affected by effluvia from the cargo in the hold. Arrowroot contains i6| per cent, of water, and 82 \ per cent, of starch, along with only about o-8 per cent, of proteid and o - 2 per cent, of mineral matter. The composition of these preparations when cooked by boiling and ready for eating is as follows : x Sago. Arrowroot. Water . 8g-oo per cent. 93-41 per cent Proteid ■ 138 ., 030 Fat '04 , , trace Starch ■ 937 6'io ,, Cellulose . . 001 O'OI ,, Mineral matter . o'o8 0"02 ,, Tous les Mois resembles arrowroot very closely. It is derived from the root of Carina edulis, a West Indian plant. It has an extraordinarily large starch grain — the largest known, indeed; but apparently it is poor in starch cellulose, for it is very easily digested, and makes excellent blancmange. Salep is a starchy preparation derived from the roots of various species of orchis, and imported into England from Smyrna. The digestibility ' of arrowroot and its allies in the stomach is probably much the same as in the case of tapioca, and their absorp- 1 Analyses by Katherine J. Williams {loc. cit., footnote, p. 239). TAPIOCA, SAGO AND ARROWROOT 247 tion in the intestine is exceedingly complete. This gives them a special value in the treatment of diarrhoea. As regards the nutritive value of all these preparations, it must be remembered that they are simply agreeable forms of starch; in other words, they consist almost entirely of carbohydrate, and should therefore not be eaten alone, but along with substances rich in proteid and fat. Eggs and milk are typical examples of such substances, and accordingly one finds that people have made puddings of tapioca, sago, or arrowroot along with milk and eggs before anything was known of the chemical constituents of the diet. Tapioca pudding has something like the following composition : Water . . 61 8 per cent. Proteid .. 36 Fat 37 „ Carbohydrates .. .. .. .. 300 ,, Mineral matters 09 „ and has a fuel value of about 780 Calories per pound (Atwater). It must be regarded as a highly nutritious food. A cupful of water-arrowroot contains only about 30 grains of starch. It would furnish to the body about 9 Calories of fuel value, while even an invalid requires about 2,000 Calories daily. When one considers the economy of these different preparations, one may say that tapioca and sago are worth the price paid for them, while the better qualities of arrowroot certainly are not. Starch at 4d. a pound is really rather dearer than tapioca at 3d. or sago at 2d., even although it contains 10 per cent, more nutriment. Apart altogether from that also, one cannot eat pure starch, whereas the same chemical substance in the form of tapioca or sago is quite agreeable. On the other hand, Bermuda arrowroot at 2s. gd., or even is. 6d., the pound is a purely luxurious article. The cheaper kinds at 4d. to 5£d. are quite as nutritious, and there can be no physiological objection to the substitution for a genuine article of the so-called Farina or English arrowroot, prepared from the starch of maize or potatoes, at 3d. per pound. Even although it requires more of these to make a jelly than of the genuine arrowroot, yet tbi« difference is far more than made up for by the difference in price. {248] CHAPTER XIV VEGETABLES— FRUITS— NUTS— FUNGI— ALG.E AND LICHENS Vegetables. The leaves of green vegetables are to be regarded as the lungs of the plant to which they belong. They are merely a sort of frame- work on which the green colouring matter, 1 by which the plant feeds and breathes, is spread out. In no sense are they, like the roots, storehouses of reserve nutriment. One would not, therefore, expect that such leaves would have high nutritive value, and chemical analysis entirely confirms the expectation. Speaking generally, it may be said that green vegetables contain a great deal of water, almost no nitrogenous matter 2 or fat, and only a small quantity of carbohydrates (2 to 8 per cent.). This small proportion of carbo- hydrates renders their use, especially as carriers of fat, admissible in diabetes. Their framework contains a good deal of cellulose. The amount of mineral matter which they contain is relatively large, and confers upon them much of what value they possess as foods. COMPOSITION OF VEGETABLES. Water. Nitro- genous Matter.3 Fat. Carbo- hydrates. Mineral Matter. Cellu- lose. Fuel Value per lb. Calories. Cabbage . . 896 18 04 58 13 II 165 „ (cooked) 97'4 o-6 01 04 013 I'3 Cauliflower (head) 907 22 04 47 08 I'2 175 Sea-kale 93'3 i'4 3-8 06 09 ,, (cooked) .. 97'95 04 007 03 02 II Spinach 906 2'5 05 38 17 09 120 1 Chlorophyll itself is of no nutritive value, but leaves the body hardly changed. 2 Even of what nitrogenous matter is present only about half is in the form of proteid. 3 Probably only about half of the nitrogenous matter consists of proteid. COMPOSITION OF VEGETABLES 249 COMPOSITION OF VEGETABLES— continued. Water. Nitro- genous Matter l Fat. Carbo- hydrates. Mineral Matter. Cellu- lose. Fuel Value per lb. Calories. Vegetable marrow 948 •06 0'2 26 05 I'3 Vegetable marrow (cooked) 99-17 009 OO4 0-2 005 o-37 Brussels sprouts . . 937 1 '5 OI 34 '•3 95 Tomatoes . . 919 l'3 02 5° °7 I-I 105 „ (cooked) 94-07 10 02 01 076 i'5 Greens 829 38 09 89 35 — 275 Lettuce 94- 1 l'4 04 26 10 o'5 105 ,, (cooked) . . 97-2 o'5 Ol6 OS 04 09 Leeks gi-8 12 »'5 58 07 — 150 Celery 93'4 I'4 01 3-3 09 09 85 „ (cooked) 97-0 °'3 006 0-8 °'5 10 Turnip cabbage . . 871 26 2 71 i'5 i'3 145 Rhubarb 946 07 07 23 06 11 105 Macedoine (tinned) 93 1 1-4 45 10 — no Watercress 93' 1 07 05 37 i'3 07 Cucumber 95 9 08 01 21 04 OS 70 „ (cooked) 974 05 002 07 02 09 Asparagus^ 917 22 02 29 09 21 XIO Salsify (cooked) . . 872 12 008 90 03 22 Endives 940 10 — 3° 08 o-6 Savoys 87 33 07 60 1-6 12 Red cabbage 900 i-8 019 5'8 07 12 Sauerkraut 910 1-4 07 28 17 09 (acids 1-26) CARBOHYDRATE. CELLULOSE. MIN. MAT EXTRACT- 50 V. 100 V. Fig. 22. — Percentage Composition of a Cabbage, and loss of each Constituent on Boiling. * Probably only about half of the nitrogenous matter consists of proteid. 2 Asparagus contains asparagin, which confers upon it slight diuretic pro- perties. The characteristic odour in the urine which follows the eating of asparagus is due to a volatile sulphur compound which is produced from it in the intestine. 250 FOOD AND DIETETICS These facts regarding the composition of green vegetables will be better realized by a study of Figs. 22 and 23. The former represents the composition of a cabbage, i.e, a typical green vegetable, while the latter depicts the ingredients of a cucumber, which is a type of one of the least nutritive of this class of foods. The effect of cooking upon green vegetables is still further to reduce their already poor stock of nutrients. They gain water, and lose part of their carbohydrate and proteid, much of their mineral Fig. 23. — Percentage Composition of a Cucumber. matter, and nearly the whole of their non-albuminoid nitrogenous constituents. For example, a cabbage loses by boiling 30 per cent, of its total solids, this being made up of about half of the total mineral matter, one-third of the carbohydrate, the whole of the non-proteid nitrogen, and 5 to 10 per cent, of the proteid (see Fig. 22). The amount of water gained by some of the commoner vegetables as the result of cooking is shown in the following table I 1 GAIN OF WATER ON COOKING VEGETABLES. Parsnips Artichokes Cabbage . . Spinach . . . . . . Cauliflower Sea-kale Vegetable marrow The next table shows the amount of carbohydrate contained in some of the commoner vegetables, and (in some cases) the loss on boiling : 2 Percent, of Water in Raw State. 820 800 890 goo 908 93 '3 948 Percent, of Water after Cooking. 972 916 975 980 964 979 99'I Increase. 15-2 n-6 8'5 80 5'6 46 43 Cabbage turnip (young) Cauliflower . . Spinach Winter cabbage Asparagus . . Savoys Raw (per cent.). •- 309 .. 210 • • 297 •■ 675 After Boiling and Straining (per cent.). 243 1 '40 085 320 16 27 1 From analyses by Katherine J. Williams, Journ. o/Chem. Soc, 1892, lxi. 226. a From analyses by Kraus, Zeit. /. Diat. und Physik. Therap., 1898, i. 69. EFFECTS OF COOKING ON VEGETABLES 251 The deficiency of fat in vegetables is often made up by the addition of butter or oil, in the course of preparation for the table. Vegetables may thus be made an important vehicle for conveying fat into the body. The proportion of fat which some vegetables can take up without being overloaded is as follows : J 10 parts of potato puree can take up . . 50 parts of II II boiled potato ,, n ■• . 4°-5o ■ > II baked „ „ ■ n 11 red cabbage „ • 1 • • 40 „ l» M savoy cabbage •• . 32 3» S» cabbage lettuce ,, •■ 24 „ • • •• potato souffle ,, ■■ 20 „ .. fried potatoes „ .1 • 15 Vegetables, as a whole, are not easily digested by the stomach. Five and one-third ounces of cabbage require three hours. Cauli- flower, it is worth knowing, is much the most easily digested of all of them. Five and one-third ounces of it require only two and a quarter hours. In the intestine also vegetables are difficult to deal with. The reason for this is their bulk and the amount of cellulose which they contain. Gases are produced by the action of organisms on the cellulose, and from this flatulence is apt to result. Fermentation is specially apt to occur when the vegetables are a little stale. To be wholesome they should always be eaten as fresh as possible. The absorption of the nutritive constituents of most vegetables is also rather defective. They constitute one of the few forms of food from which even starch is not . completely absorbed. The average waste on green vegetables is approximately as follows (Rubner) : Dry substance .. 15-0 per cent. lost I Carbohydrates .. 15-4 per cent, lost Proteid .. .. 180 „ ,, | Mineral constituents 228 ,, ,, When one realizes that green vegetables are poor in nutrients to start with, that they become still poorer as the result of cooking, and that even of the remnant which reaches the intestine a large part escapes absorption, one will readily understand that, considered as foods, they are of very low nutritive value. Indeed, it may be said that green vegetables are only of use in the diet for two reasons. First, they supply ballast to the intestine ; the indigestible residue which they leave is a stimulus to the intestinal movements. Hence their special value in constipation. Secondly, they are a valuable 1 From analyses by Kraus, Zeit. f. Didt. und Physih. Therap., 1898, i. 69. 252 FOOD AND DIETETICS source of mineral salts. The most abundant of these are compounds of potash, which have an alkaline reaction, and help to keep the blood supplied with alkali and to lower the acidity of the urine. It is probably owing to their richness in alkaline salts that the use of green vegetables is helpful in some diseases of the skin. Thus, Clement Dukes points out that he has several times seen epidemics of eczema result from a deficiency of green vegetables in the diet (' School Diet,' p. 103). For the same reason the free use of green vegetables should be recommended to patients who suffer from gravel. Their value in scurvy has long been known, cabbage being a most valuable antiscorbutic, and serviceable also in minor forms of scurvy, such as purpura and bleeding from the gums. Some vegetables, such as rhubarb, contain a good deal of oxalic acid. These should be avoided in cases of gravel. The sour taste of tomatoes is due to citric acid, not to oxalic, as is often stated. Asparagus and onions are the only vegetables which contain appreciable amounts of uric acid-forming bodies. Green vegetables do not contain much iron, for that element, if present at all in the green colouring matter, is merely there in traces. The value of the mineral ingredients of vegetables will be dealt with more fully in a subsequent chapter. Fruits. The fruit is not of direct benefit to the plant. It is intended as a bait to attract birds or insects, and so insure the liberation or transportation of the seed. Hence the aesthetic qualities pre- proteid. EXTRACT. CARBOHYDRATE MIN. MAT. CELLULOSE. ACIDS. Fig. 24. — Percentage Composition of a Strawberry. dominate in fruit rather than the strictly nutritive, and we eat them more for the sake of their sweetness and flavour than for the actual nourishment which they afford. COMPOSITION OF FRUITS The general composition of fresh fruit is something like this : 253 Water Proteid Fat 85 to 90 per cent. 05 0-5 Carbohydrates . . Si to ioj per cent. Cellulose .. ..24 „ Mineral matters ..0-5 ., WATER. CARBOHYDRATE MIN. MAT. ACIDS. CELLULOSE^ Fig. 25. — Percentage Composition of an Apple. The composition of individual members of the group is shown in the following table, and a study of the graphic representation of some typical fruits will illustrate it (Figs. 24, 25, and 26). AVERAGE COMPOSITION OF FRUITS (EDIBLE FORTION). Water. Proteid. Ether Extract. Carbo- hydrates. Ash. 04 Cellu- lose. Acids. Apples 82-5 04 °'5 I2'5 27 ro „ (dried) 362 I'4 30 49- 1 i-8 4" 3 36 Pears 839 04 o-6 H'S 0-4 3' 1 O'l Apricots 850 II . ■> 124 o-5 10 Peaches . . . . 88 8 03 0'2 5-8 06 34 07 Greengages 808 04 — 13-4 03 4 1 i-o Plums 78-4 10 ? 148 o"5 4'3 X'O Nectarines 829 o-6 f 159 06 Cherries . . . . 840 08 08 100 o-6 38 i-o to 1-5 (Stutzer) Gooseberries 860 04 89 °'S 27 I- 5 Currants (red, black and white) 852 04 — 79 OS 46 i - 4 Strawberries 891 10 05 63 07 22 10 to 12 Whortleberries ( = Blaeberries or Bil- berries) 763 07 30 5'8 0-4 122 16 Blackberries 88-9 09 21 23 o-6 S'2 Raspberries 84-4 I'O ? 5'2 06 7"4 l'4 Cranberries 86-5 05 07 39 02 62 2'0 tO 2'5 Mulberries 84-7 °3 114 o-6 09 18 254 FOOD AND DIETETICS AVERAGE COMPOSITION OF FRUITS (EDIBLE PORTION)— continued. Water. Proteid. Ei her Extract Carbo- '. hydrates. Ash. Cellu- lose. Acids. Grapes 79 -o 10 I - i5'5 0'5 2'5 °"5 Melons 89-8 07 0'3 7-6 06 10 Water-melons 92 9 °'3 O I 6 '5 02 Bananas 74'° 1 '5 07 22 9 0-9 0-2 Oranges 867 09 0-6 87 o-6 1 '5 10 to 25 Orange- juice 85-0 — — io-8 — i'93 Lemons 89-3 1 0-9 8'3 °'5 Lemon-juice 90 'O — — 2'0 04 — 70 (citric acid) Pineapples 893 °'4 0*3 97 °"3 Pomegranates 768 ^^■5 I 6 168 0-6 27 Dates (dried) 20-8 4 '4 2 I 657 1 '5 5 '5 Figs (dried) 20'0 5'5 0-9 62 8 23 7'3 12 ,, (fresh) 79' I i'5 — 18-8 06 Prunes (dried) 26-4 2-4 o-8 66-2 1 "5 — 27 (fresh) . . 80-2 0-8 ? 18-5 °5 Currants (dried) . . 279 I '2 30 64 'O 2 - 2 17 Raisins 14 'O 2'5 47 747 4 ' Olives 67 'O 2 '5 17-1 57 44 3 "3 Rhubarb Stalks . . 94 '4 o-6 07 25 I'l 07 The composition of edible parts only is represented. Where cellulose is not given it is included with carbohydrates. It will be observed that the only nutritive element of any importance in fruit is the carbohydrate group. As a general rule, about half to three-quarters of the total carbohydrates in a fruit consist of sugar. The particular variety is that known as fruit-sugar, or, in chemical language, lffivulose ; but some fruits, e.g., apples, apricots, and pine- apples, contain a considerable amount of cane-sugar as well. It is of some importance to remember this, for lavulose is certainly more easily assimilated by diabetics than other sugars are, so that fruits may often be allowed in mild cases of that disease with impunity. The total amount of sugar contained in some typical fruits is shown in the following table i 1 Total Sugar Total Sugar (j>er cent.). (per cent.). Hot-house grapes . 1726 Preserved apples ■ 6-25 Preserved „ • 1650 Raspberries • 7'23 Figs (fresh) ■ "'55 Oranges • 8-58 Cherries I0 - 00 Apricots . 878 Preserved pears . 878 Pineapples • i3'3i Fresh pears ■ 784 Plums • 1 '99 White currants 6-40 Lemons • 1 '47 Strawberries . 586 The remainder of the carbohydrates is made up of vegetable gums. Many of these seem to belong to that group of 'pectin bodies ' to which reference has already been made (p. 163). In the 1 Analyses by Buignet (quoted by Konig). COMPOSITION OF FRUITS 255 course of ripening, some of them seem to be converted into the corresponding sugar — pentose, the nutritive value of which must be regarded as very doubtful. When subjected to boiling, the gums of many fruits yield a jelly, the production of which is familiar in the process of making preserves. The amount of cellulose varies greatly in different fruits. It is always lessened by the process of cultivation — witness the difference between a crab apple and a Newton pippin — and it diminishes also, by a sort of natural digestion, during the ripening of the fruit. The mineral constituents of fruits are of considerable importance. They consist mainly of potash united with various vegetable acids, such as tartaric, citric, and malic. These have an agreeable acid flavour, but when burnt up inside the body are converted into the corresponding carbonate, and so help to render the blood more alkaline and the urine less acid. Thus, 1 fluid ounce of lemon- juice contains 45 grains of citric acid and saturates 45^ grains of bicarbonate of soda. In some diseases, such as scurvy, this property of the mineral constituents of fresh fruit is turned to therapeutic account. As the fruit ripens, these vegetable acids diminish to some extent, and it is to this fact, coupled with an increase in the amount of sugar present, that the sweetness of ripe as compared with unripe fruit is due. The earthy salts are but poorly represented among the mineral ingredients of fruits, and for this reason the free use of fruit in place of cereals has been recommended by some writers to persons suffering from atheroma. The odour and flavour of fruits are due to the presence of very small quantities of ethereal bodies which sometimes elude chemical investigation. In many cases, however, we have been able to obtain (from coal-tar, too, of all sources) artificial products which have precisely the same flavour as many fruits. These products form the basis of the different fruit flavourings and essences sold in the shops. Although of no nutritive value, the flavouring sub- stances contained in fruits are by no means to be despised as stimu- lants to the appetite and aids to digestion. Cooking renders most fruits more digestible by softening their cellulose, and it also, as we have seen, converts the gums into a gelatinaus form. But these changes are not brought about without a good deal of loss. The loss affects all the ingredients of the fruit. The following instances show the exact figures for the carbo- hydrates ■} 1 From analyses by Kraus, Zeit.f. Diat. u. Physik. Therap., 1898, i. 69. 256 FOOD AND DIETETICS Raw apples 1 1 "7 per cent. Pears once boiled . 6*6 per cent. Apples once boiled 7\3 ,, twice „ 59 , , twice , , 61 Raw peaches 95 Raw pears io'i „ Peaches once boiled 18 „ Where, as is usually the case, the fruit is cooked by stewing and the juice eaten along with it, this effect of cooking is of no moment. The digestibility of fruit in the stomach and intestine is dependent largely on the nature of the fruit and its degree of ripeness. Five and a third ounces of raw ripe apple (one large or two small apples) require about three hours and ten minutes for its digestion by the stomach. On the other hand, if the fruit be unripe and the amount of cellulose consequently greater, digestion may be much more prolonged. The excess of acids present in unripe fruit causes the latter to be irritating to the intestine, and a frequent originator of diarrhoea and colic. If, however, the cellulose and acids are contained in more moderate quantity, as in ripe fruit, the gentle stimulation which they exert on the intestinal wall may be very useful. Hence it is that stewed fruit is so serviceable an addition to the diet in sluggish action of the bowels. There have been no experiments made to test the degree to which fruit is absorbed by the human intestine. One may reasonably expect it to correspond pretty closely with the absorption of fresh vegetables. In other words, the proteid will be absorbed to about 80 per cent., the fats to 90 per cent., and the carbohydrates to 95 per cent., if the conditions be reasonably favourable. From a nutritive point of view fruits may be artificially divided into the two groups of flavour-fruits and food-fruits. In the former one would include all fruits which contain more than 80 per cent, of water ; in the latter, all fruits or fruit preparations which have more than 20 per cent, of solids. The only claim of the members of the first group to be regarded as foods is that they contain a small amount of sugar in a pleasant but rather bulky form. They are chiefly eaten for the sake of their pleasant flavour. Their richness in water makes them more adapted to the requirements of the inhabitants of warm countries than for use in northerly latitudes, and one finds that if they are freely represented in the diet less water requires to be consumed. Grapes stand intermediate between the two groups, for their juice contains an amount of sugar which varies from 10 per cent, in the poorer up to 30 per cent, in the richer varieties. In the so-called grape-cure, from 1 to 8 pounds of grapes are taken daily in divided quantities, and between meals. If the rest of the diet is sufficient, the patient may gain weight on this regimen, while the grape-juice, THE BANANA 257 WATER. owing mainly to the organic acids which it contains, acts as a mild laxative and diuretic, and at the same time diminishes slightly the acidity of the urine. In this, as in all similar ' treatments,' much of the credit of the results attained must be put down to the circum- stances under which the ' cure ' is carried out, for the patient is expected to gather the grapes for himself, and doing this entails a certain amount of exercise in the fresh air. It is chiefly in cases of so-called 'abdominal plethora,' *'.«., the results of habitually eating too much and taking too little exercise, that benefit has been observed from such a course of treatment, but it is also useful in some cases of chronic bronchial catarrh. Mostelle is an unfermented grape-juice preserved by pasteurization. It contains about 25 per cent, of grape-sugar, and is a useful food -beverage, especially in fevers. The food-fruits, on the other hand, are not to be despised as sources of real nutriment. Of this group the banana is a good example. In the fresh state this fruit contains a fair amount of car- bohydrate and an appreciable amount of proteid as well, while bananas dried in the sun and sprinkled with sugar, a form in which they have recently been imported, compare favourably with dried figs in nutritive value, and are a pleasant substitute for the latter at dessert. In its ordinary form, however, the Fig- 26.— Percentage Compo- . . , „ , , , sition of a Banana. banana is too bulky to be able to serve as the main constituent of a healthy diet. Assuming that an average sized specimen weighs 45 grammes or i|- ounces (without the husk), it would require about eighty of these to yield the amount of energy required daily, and nearly double that number to supply the requisite amount of proteid. 1 No wonder, then, that in tropical countries, where the banana is largely eaten, the inhabit- ants are apt to show an undue abdominal development. 1 These quantities have been calculated from European dietary standards, and represent the amount of energy and proteid required by a man in this country. On the Gold Coast, however, as Mr. C. G. Moore informs me, the natives eat about eight plantains (the equivalent of about sixteen bananas) daily, supple- mented occasionally by a little dried fish, and on this diet they manage to perform a fair amount of work, 1-7 CARBOHYDRATE MIN. MAT. CELLULOSE. 258 FOOD AND DIETETICS The unripe banana is dried and used to produce banana meal or flour. A sample of such a flour had the following composition : Banana Flour. Wheat Flour, Moisture .. .. .. 130 per cent. 13-8 per cent. Proteid .. .. .. .. 4-0 ,, yg ,, Fat 0-5 „ 14 „ Carbohydrates.. .. .. 8o - o ,, 76'4 „ Mineral matter .. .. 2-5 „ 05 „ I have placed alongside of it the composition of good wheat flour, compared with which the banana-meal is rich in carbo- hydrates and mineral matter, but very poor in proteid. If rice, on the other hand, had been taken for comparison, it would have been found that banana flour was about equal to it in nutritive value. Bananina 1 is a proprietary food obtained from the banana by a special process after the fibrous matter has been extracted and is designed for the use of infants and invalids. For an analysis of it, see p. 469. It consists chiefly of starch, but is said to be very easily digested. Banana flour can be used to make a sort of bread, and it is said to be easy of digestion. Two pounds of such flour and a quarter of a pound of salt meat or fish is stated to form the daily allowance for* a labourer in tropical America (Johnston). Another advantage of the banana is the cheapness with which it can be produced. A given area of ground devoted to its cultivation will yield a larger food return than in any other form, unless it be planted with chestnut-trees. 'A spot of a little more than 1,000 square feet will contain from thirty to forty banana plants. A cluster of bananas produced on a single plant often contains from 160 to 180 fruits, and weighs from 70 to 80 pounds. But reckoning the weight of a cluster only at 40 pounds, such a plantation would produce more than 4,000 pounds of nutritive substance. M. Humboldt calculates that as 33 pounds of wheat and 99 pounds of potatoes require the same space as that in which 4,000 pounds of bananas are grown, the produce of bananas is consequently to that of wheat as 133 : 1, and to that of potatoes as 44: 1. . . . A much greater number of individuals may be sup- ported on the produce of a piece of ground planted with bananas, compared with a piece the same size in Europe growing wheat. Humboldt estimates the proportion as 25 to 1 ; and he illustrates the fact by remarking that a European, newly arrived in the torrid zone, is struck with nothing so much as the smallness of the spots 1 The Banana Food Co., 46, Artillery Lane, E.C. NUTS 259 under cultivation round a cabin which contains a numerous family of Indians ' (Knight). It is evident from this that we possess in the banana a potential source of cheap nourishment which may one day be of great importance. Surpassing even the banana in nutritive value is the group of dried fruits, which includes such examples as the date and the raisin. The former, indeed, is as much a staple article of diet to the Egyptian as rice is to the Hindu, but the carbohydrate of rice is mainly in the form of starch, whereas in the date it is almost solely present as sugar. ' A half-pound of dates and half a pint of milk makes an ample and satisfying meal for a person engaged in sedentary labour ' (Densmore). The fig is another valuable member of this group. Dried figs contain about 50 per cent, of sugar and 3-5 per cent, of proteid. Weight for weight, they are more nourishing than bread, and a pint of milk and 6 ounces of dried figs makes a good meal. One and a half pounds of them yield 400 grammes of carbohydrate, or four-fifths of the total amount of that nutritive ingredient required daily. AVERAGE COMPOSITION OF DRIED FRUITS (EDIBLE PORTION). Water. Proteid. Ether Extract. Carbo- hydrates. Cellu- lose. Ash. Calorie Value per Pound. Dates Figs „ (stewed Prunes 15 '4 18-8 565 223 76-6 14 6 2 - I 4 3 12 2 - I OS 2-6 2-8 ° - 3 o - 3 01 3 '3 74-6 6S0 40 712 3-8 62 9 2"I 1 "3 2-4 23 0'5 3'4 1,615 '.475 785 1,400 (stewed) . . Raisins 22 '3 736 I 2'5 43° 1,605 Nuts. Nuts differ very markedly from the fruits which we have been considering, in that they are of very high nutritive value. Bulk for bulk, indeed, dry nuts are amongst the most nutritive foods which we possess; Their general composition is roughly as follows : 9 to 12 per cent. 3 „ 5 ,. 1 per cent. 17 — 2 Water 4 to 5 per cent. Carbohydrates Proteid .. 15 ,. zo Cellulose Fat .. .. 50 ,, 60 „ Mineral matter 26o FOOD AND DIETETICS PROTEItt FAT. CARBOHYDRATE M1N. MAT Fig. 27- CELLULOSE. -Percentage Composition of a Walnut. A graphic representation of a typical specimen of the group, the walnut, is shown in Fig. 27. It will be observed that fatty matter predominates very largely in the composition of nuts. No other vegetable substance is so rich in fats as these. Advantage has been taken of this to prepare from nuts various fatty prepara- tions which are used as cheap and efficient substitutes for ordinary butter in the kitchen. Amongst these are the commercial prepara- tions known as ' Albene,' ' Nuco- line,' ' Vegsu,' or ' vegetable suet,' : Nut Butter ' and ' Nuttolene,' also ' Cocos Butter,' ' Cocoleum,' and 'Cocolardo.' There is every reason to believe that these are equal in nutritive value to ordinary butter, whilst they are decidedly more economical. 'Albene' costs gd. per pound, and 10 ounces of it are said to go as far as 1 pound of butter. ' Nucoline ' costs 6d. per pound, and 4 pounds of it are stated to be equivalent in cooking operations to 6 pounds of butter. ' Nut Butter ' and ' Nuttolene ' contain proteid as well as fat, and are therefore to be compared to cream rather than to ordinary butter. Unfortunately, nuts are not readily digested in the stomach. This is due in part to their richness in fat, and partly also to their containing a high proportion of cellulose, which forms a dense and compact framework throughout the structure of the nut. By thorough mastication, the latter difficulty can be overcome to some extent, but it is still more efficiently dealt with by artificial grinding and cooking. Various preparations derived from nuts, in which this mechanical cause of difficulty in their digestion has been to a large extent overcome, are now in the market. Best known of these are the ' Fromm's Extract,' and the various preparations of the Sanitas Nut Food Co. (' Nuttose,' ' Bromose,' 'Nutmeal,' and ' Malted Nuts,' etc.). Fromm's Extract consists of nuts which have been crushed, and from which the excess of cellulose and oil have been removed. The preparation is then cooked under special conditions, which develops in it a flavour not unlike that of meat. It has the following composition : NUTS 261 FROMM'S EXTRACT. Water .. 253 per cent. Carbohydrates and Proteid .. 21-9 „ cellulose 8-3 per cent. Fat .. •• 316 „ Mineral matter 12-8 There can be no doubt that this is a preparation of high nutritive value. It costs, however, 3s. 6d. per pound. The following is the composition of malted nuts : Water 4'5 per cent. Maltose • 49'3 per cent. Proteid • • 23-6 Mineral matter 2'2 ,, Fat .. • ■ 20-4 But few experiments have been made on the absorbability of nuts. In one which was carried out in America, 1 and in which the subject of experiment lived solely on a diet of fruit and nuts, it was found that 82-5 per cent, of the proteid, 86-g per cent, of the fat, and 96 per cent, of the non-nitrogenous matters were absorbed. This result compares favourably with the absorption of an ordinary mixed diet except that it shows a rather greater waste of proteid, and shows that it is quite possible, for long periods at any rate, to supply the requisite proteid and energy from a diet made up of selected fruits and nuts. The nutritive value of nuts is no doubt extremely high, and when suitably prepared they may form substitutes for meat to a consider- able extent, for they resemble the latter in containing much proteid and fat in small bulk. They are an even more concentrated food than cheese, and should rather be used as part of the ordinary diet than as a supplement to an otherwise large meal. Thirty large walnuts (weighing, without the shells, 100 grammes) would contain as much fat as i\ pounds of moderately lean beef, but 2§ ounces of such beef would be equal to them in proteid. It would be necessary to consume about 700 walnuts in order to obtain the necessary amount of proteid required by the body every day: A cocoanut weighing ij pounds contains \ pound of fat. Its price is about 2d., so that as a source of fat it is equivalent to butter at 8d. the pound. Of all the members of this class of foods, the chestnut is probably of the greatest general value as an article of diet. This is due to its containing a high proportion of carbohydrates along with much pro- teid and fat, as is shown in the following recent analyses : 1 'Nutrition Investigations among Fruitarians and Chinese,' U.S. Department of Agriculture, Office of Experiment Stations, Bull. No. 107, 1901. For more recent experiments, which, however, yielded substantially the same results, see ' Nuts and their Uses as Foods,' Farmers' Bull. No. 332, 1908. 262 FOOD AND DIETETICS COMPOSITION OF CHESTNUTS.! __ H 2 0. Mini- f Normal mum ( Dried . . Maxi- / Normal mum ( Dried . . 5280 000 62-60 000 N Matter. 201 4'45 4'3i 1 1 05 Fat. °'45 117 173 374 Carbo- hydrates. 31-54 8217 4074 8861 Cellulose. 074 1-76 I '36 329 Ash. °57 I 24 I 22 3 06 Acidity. 0059 0164 Roasted chestnuts have 40 per cent, water. Those cooked by boiling have 72 per cent An economic point in favour of chestnuts also is the fact that a given area of ground produces the maximum amount of. human food when planted with chestnut-trees. The great value of the chestnut has been fully recognised by the poorer peasantry of Central France. During the autumn and winter they often make two meals a day from it alone. The nuts are pre- pared by removing the outside shell, blanching, and then steaming ; salt and milk are added when they are eaten. Sometimes they are ground after blanching, and the meal made into flat cakes. The almond is another very valuable form of nut, being specially noteworthy for the large amount of nitrogenous matter which it contains. It has the further advantage of being compact and portable. ' No man,' it has been said, ' need starve on a journey who can fill his waistcoat pocket with almonds.' Owing to its poverty in carbohydrates, the almond is largely employed in the manufacture of diabetic breads. The detailed composition of the commoner varieties qf nuts is exhibited in the following table : COMPOSITION OF NUTS (EDIBLE PORTION). Water. Proteid. Fat. Carbo- hydrates Cellu- lose. Mineral Matter. Chestnuts (fresh) 38-5 66 8-o 45-2 *7 (dried) 5-« 101 100 7i - 4 27 Walnuts (fresh) 44 - 5 12 'O 3 v6 9*4 o-8 17 „ (dried) 4fa 15-6 626 7'4 .. 78 2'0 Filberts and hazels (fresh) . . 480 80 28-5 1* '5 2-5 IS „ (dried) .. 37 14-9 664 97 32 18 Sweet almonds 6-o 240 54'° IO'O 3'° 30 Pistachio kernels 7'4 21 7 5it I4'0 2-5 3 3 Cocoanut (fleshy part) 46-6 5-2 359 8-4 29 I'O , , (dried) 3-5 6-o 57 4 31-8 i - 3 (milk) 903 °'5 — 9'° — Hickory nuts 60 150 65-0 120 2-0 Brazil nuts 5-o 17 'O 67-2 7'° 4-0 Pea nuts (kernels) 9 '3 27-9 42 - o 187 2 - I 1 Balland, ref. Analyst, 1897, p. 216. FUNGI 2 6 J Fungi. The edible fungi are popularly spoken of as mushrooms, and the inedible ones as toadstools. There is really, however, no such division, for all the larger fleshy fungi are toadstools, and probably most of them are edible. The word ' mushroom ' has therefore only the practical convenience of distinguishing the best-known edible fungi met with in commerce. There are about 1,400 species of toadstools met with in this country, and of these about a hundred are known to be edible, while not more than thirty have been definitely proved to be poisonous. There are probably a great many more edible varieties, but the only way of finding out whether they are so or not is by trying — a mode of experiment which is somewhat risky. But our ignorance in this respect need not be a matter of regret, for even although many more toadstools should be found to be harmless, yet they are probably not worth the eating. The poisonous properties of fungi are due to the presence in them of alkaloids. The nature of these differs in the different species, so that the symptoms of toadstool-poisoning are varied. The genus Amanita, most of which are very dangerous, contains an alkaloid ' Amanita toxin,' 1 which acts as an irritant to the stomach and bowels, and also paralyzes the nervous system. This poison is peculiar in that it does not exert its effects for some hours after the fungus has been swallowed, so that at first the patient feels perfectly well. It is, however, extremely potent, so that a very small portion of such a fungus may prove fatal. The alkaloid found in the poisonous examples of Russula and Lactarius is purely irritant in its effects, and induces vomiting and diarrhoea, thus leading to the discharge of the fungus, and bringing about its own cure. The symptoms, too, follow immediately upon the eating of the fungus, and without any delay. The Agaricus muscarius contains the alkaloid muscarin, which produces symptoms very much resembling those of cholera. The Czar Alexis lost his life by eating it. It is not easy to lay down definite rules for the recognition of the harmless fungi, while, unfortunately, some of the most dangerous are .also those of commonest growth. Certain general indications it is always safe to observe. Thus, all fungi should be avoided when they are overripe, or when they have been attacked by slugs. Those that soften easily are usually dangerous, and the same is true of fungi which grow in dirty situations, such as dunghills, for this 1 See Ford ('A Consideration of the Boisons of Amanita Phalloides '), Brit. Med. Journ., 1906, ii. 1541. 264 FOOD AND DIETETICS plant has a great tendency to absorb poisons from the medium on which it happens to be growing. Lastly, all those which have a disagreeable smell or taste should certainly be rejected. The fungus-eater's safest ground is unquestionably amongst the Boletus family. The distinguishing mark of these fungi, as opposed to the Agarici is that they have tubes under the cap instead of gills Of the forty-nine native species of this family, most are edible, and many quite excellent. But there are exceptions, one or two members being virulently poisonous. There need not, however, be any difficulty in distinguishing these, for all the safe ones are characterized by being yellow beneath the cap. To this rule there is only one exception, and it is easily told by its scarlet stem. All those that are red or pink or orange or brown beneath the cap should be avoided. It is well also to discard all those which change colour on cutting or bruising. The Boletus edulis occurs abundantly in beech woods, especially in the South of England. It has a light brown cap, the under part of which is first white and then yellow-green, with a thickish pale brown stem, surmounted by a fine white network. This network is the best feature by which to distinguish it from its congeners. It is in best edible condition when the under surface is yellowish. Belonging to a different family (the Hydnei, or teeth-bearing fungi) is the Hydnum repandum — the urchin of the wood. It is of a buff white colour, and is easily recognised by the long unequal spines beneath its cap. It is amongst the most delicate of toadstools, having a slight flavour of oysters. It is best in the young and fresh state, and is largely employed as food in Belgium, Austria, and France. The Agaricus family includes a large number of edible fungi, the best known of which is the common mushroom (Agaricus campestris). Another favourite is the Agaricus gambosus, or St. George's mushroom, which is found in spring and early summer, growing on downs and pastures, often in immense fairy-rings. Its stem is stout and solid, and the gills yellowish -white and much crowded together. It has a strong odour of fresh meat, which is so powerful that workmen employed to root out the fungus are said to have been so overcome by the odour as to be compelled to desist (Cook). It is better eating than the common mushroom. One of the best of all is the Paxillus giganteus, which is found in August and September. It is firm in texture and of a dingy white colour with yellow stains on the stem. It is easily identified by its fine, creamy white gills and its broad inrolled disc. The Lactarius deliciosus and the Cantkarellus Cibarius (chantrelle) COMPOSITION OF FUNGI 265 belong to different groups. The former, as its name implies, is one of the nicest of all edible fungi. It is not difficult to recognise, but is apt to be attacked by a reddish parasitic fungus, and in that state is dangerous. It is of an orange colour with a yellowish, milky juice, and grows abundantly in fir plantations. The chantrelle is found in large numbers in most of our woods in autumn. It is orange yellow both within and without, and has a pleasant smell of ripe apricots. It has a delightful flavour, and one writer goes the length of saying that if properly prepared ' it would arrest the pangs of death !' The common morel (Morchella esculenta) and the truffle (Tuber cibarium) are both much - prized fungi. The former grows in England, but is usually imported from abroad in a dried state, and fetches a high price. The truffle is an underground fungus which grows in dry soils. In England it is chiefly found in Wiltshire, Hampshire, and Kent. The black variety is most esteemed. Both morels and truffles are chiefly valued for their delicate flavour, and are common constituents of seasonings and sauces. Though usually eaten dried, they are very much better when fresh. The chemical composition of the commoner edible fungi is shown in the following table : COMPOSITION OF FUNGI. 1 Mushroom (Agaricus campestris). Chantrelle (Caw ha- re Uus cibartus). Truffle ( Tuber cibarium). Edible Boletus (Bole :us edulis). Lactarius deliciosus. Moisture . . . . Amides, etc. . . . . Carbohydrates Cellulose Mineral matter 937 ''3 22 OS 1-2 II °'3 9093 064 119 064 5°9 o'33 1 20 73 1 '4 61 06 6 - 02 64 20 84- 19 26 37 04 465 °74 8908 091 i-88 054 449 032 The following analysis of the solids and nitrogenous matter in tinned French mushrooms, is given by Saltet : 2 Dry Substance. Total Nitrogen. Percentage of N in Dry Substance. Proportion of the Total N present. Mushrooms Fluid in tin 3784 891 27 , 048 3 7-13 5"39 849 151 Together . . 4675 3l8 6-8 lOO'O 1 Chiefly compiled from analyses by Stahl-Schroder, Maly's Jahres-Bericht Thier-Chemie, 1897, xxvii. 699. See also Lafayette B. Mendel, American Journal of Physiology, 1898, i. 225. 2 Archiv. f. Hygiene, 1885, iii. 443. 3 Probably mostly in form of amides. 266 FOOD AND DIETETICS It will be observed that as a class they contain but little dry substance. Of this, a comparatively large amount is nitro- genous matter, the remainder being chiefly made up of carbo- hydrates. The older fungi contain more nitrogen than the younger plants, and those which are cultivated are richer than those which grow wild. It must not, however, be supposed that the nitrogenous matter of the fungi is all in a form available for nutrition. On the contrary, a large proportion of it is in the form of amides and other non-proteid bodies. Indeed, a reference to the table will show that the actual amount of albuminoid matter which the fungi contain is, with the exception, perhaps, of truffles, by no means large at all. It is probably to the amides and their allies that most of the peculiar flavour of the fungi is to be attributed. Recent analyses 1 of the different forms of nitrogen present in some common fungi have yielded the following results : Cantha- rtl us Cibarius. Boletus Edulis. Lactarius Deliciosus. Morckella Esculenta. Agaricus Campestru. Proteid N ' Extractive ' N . . Indigestible proteid N Digestible ,, 269 229 O40 I 46 o«79 3-8 7 273 1-14 065 210 3" 251 060 I- 4 I 499 418 081 1 -go 219 738 489 249 117 364 Starch is not represented amongst the carbohydrates of the fungi. They contain instead a curious and rare sugar called trehalose (mycose) 2 and a substance termed mannite, which is the parent of a sugar named mannose. The nutritive value of both of these sub- stances is unknown. There is some reason to believe that mannite, at least, is not easily assimilated. 3 The fungi contain also a good deal of cellulose, which seems to differ somewhat from that found in most plants. As a result of cooking fungi shrivel up considerably. This is due to coagulation of the contents of the cells, which shrink instead of bursting, as they probably would do if they contained starch. They lose, also, much of their non-albuminoid nitrogenous constituents, and with these much of their flavour. They also gain in water to some extent, so that a stewed mushroom contains only about 2 per cent, of solid matter. 4 1 Mendel, Amer. Journ. of Physiolog., 1898, i. 225. 2 Winterstein, Zeit. f. Physiolog. Chem., 1899, xxvi. 438. s Jaffe, Zeit. f. Physiolog. Chem., 1883, vii. 297. 4 See analysis by Katherine J. Williams, Journ. of Chem. Soc, 1892, xi. 226. NUTRITIVE VALUE OF FUNGI 267 Fungi are not easily digested in the stomach. This is matter of common knowledge. The difficulty is probably largely due to the amount of cellulose which they contain, and to the shrinkage and greater compactness which result from cooking. The pain and dis- comfort which they are apt to produce in the stomach have often been wrongly attributed to poisons, and in consequence fungi which are merely indigestible have been regarded as inedible. Recent experiments in vitro have amply confirmed their indigestibility. 1 The absorption of the fungi is also very imperfect. One observer 2 took large quantities of fresh mushrooms daily. He found that 19 per cent, of the dry substance and 33*7 per cent, of the proteid escaped absorption. Another got even less favourable results, 3 two- fifths of the proteid being excreted unchanged. Artificial digestion outside the body has yielded similar results. 4 On the other hand, as one would expect, the absorption is considerably better if the mushrooms are taken in the form of powder, but even in that case 29 per cent, of the proteid was lost. 5 On the whole, mushrooms and other fungi must be ranked with such substances as green vegetables, carrots and black-bread as amongst the wasteful foods. The nutritive value of the fungi has been very much exaggerated. Thus, they have been described as vegetable beefsteaks ; it has been pointed out that the Patagonians and natives of Terra del Fuego live largely upon tbem, and their more extensive use has been urged upon the poorer classes in this country. This is partly owing to the failure to recognise that about one-third of their nitrogenous matter is in a form which is useless for the purposes of nutrition, and partly to ignorance of the very imperfect degree to which such foods are capable of being absorbed. Further, the carbohydrates which the fungi contain must be regarded as of very uncertain nutritive value. The fungi cannot, therefore, be looked upon as foods of any greater value and importance than fresh vegetables, and when one considers the high price paid for many of them, such as truffles, they must be regarded as pure luxuries. This conclusion was arrived at as early as 1824 by Dr. Kitchiner, who stated in his 'Cook's Oracle' that he did not believe that mushrooms were really nutritious. Pereira expressed a similar opinion twenty years later. It only remains to 1 Gane, Food and Sanitation, April 22, 1899. 2 Saltet, Archiv.f. Hygiene, 1885, iii. 443. 8 TJffelmann, Archiv. f. Hygiene, 1887, vi. 105. 4 Morner, Zeit.f. Physiolog. Chem., 1S86, a. 503. 6 TJffelmann, Archiv.f. Hygiene, 1887, vi. 105. 268 FOOD AND DIETETICS add that when eaten in large amount they rapidly produce a feeling of satiety, and this must always constitute a further obstacle to their taking serious rank as articles of diet. Algae. This group includes the seaweeds, several varieties of which, e.g., laver, dulse, etc., are occasionally used as foods. The only one which demands special consideration is Irish or Carraigeen moss (Chondrus crispus), which is not only sometimes used as an ordinary article of diet, but finds a place also among the dietetic resources of the sick-room. Irish moss comes into the market in a dried form, and has approximately the following composition (Church) : Water 188 per cent. Nitrogenous matter . . . . . . 9/4 1 „ Mucilage, etc. .. .. .. .. 55-4 „ Cellulose . . . . 27 „ Mineral matter . . . . . . . . 14-2 „ Its chief constituent is the substance described in the analysis as ' mucilage,' but which is also known as lichenin. This substance is insoluble in cold water, but swells up and dissolves when boiled, and if present in sufficient amount sets to a yellowish jelly on cooling. Its chemical nature is obscure. When boiled with acids it yields a small quantity of sugar, but of what nature is not definitely determined. 2 Of this, however, there is no doubt, that the mucilaginous substance in Irish moss is quite unaffected by the ordinary starch-digesting fluids (saliva and pancreatic juice) met with in the body. For this reason its nutritive value must remain open to grave question, and at present one is only justified in regarding it as a substance capable of yielding a bland and soothing drink which may be of value in irritable conditions of the throat. It is sometimes recommended as a substitute for starch in cases of diabetes ; but although it may not aggravate that disease, it is very doubtful whether it contributes in any important degree to the nourishment of the patient. That this is extremely unlikely is rendered still more evident by the fact that Irish moss jelly contains only 3 per cent, of solid matter, the remainder being water. A teacupful of such jelly would furnish only ^ ounce of solid matter, or as much as the weight of a shilling. Whether the nitrogenous 1 In a specimen of Irish moss which I examined, I found only 6*3 per COM. of nitrogenous matter and i6 - 6 per cent, of ash. 2 The sugar does not appear to be glucose. I have not found that it ferments with yeast. It gives an imperfect pentose reaction with phloroglucin. The lichenin of Ireland moss gives on hydrolysis a large yield of a reducing'sugar. which ferments with yeast, and gives no phloroglucin reaction (see also p. 269). " LICHENS 269 matter of Irish moss contributes to the nourishment of the body must also be left undetermined. It is not likely that it is all present in an albuminoid form. The mineral constituents are very abundant, and contain traces of iodine, but not sufficient to exert any effects on nutrition. Lichens. The only lichen which we need consider is the so-called Iceland moss (Cetraria islandica). In its commercial form it resembles Irish moss, but is much darker in colour. According to Church's analysis, its composition is as follows : Water .. .. .. .. .. 100 per cent. Proteid 87 Lichen starch 700 ,, ,, acids, etc 6-3 „ Cellulose 35 „ Mineral matter .. .. .. .. 15 „ A more recent analysis of the commercial article dried at 105 C. has been made by Ernest W. Brown, 1 with the following result : Total nitrogen 056 per cent. Proteid nitrogen 032 „ Extractive nitrogen 014 „ Ether extract -.. .. 12 „ Cellulose .. 5 3 59 Ash • .. 2'2 „ Soluble carbohydrates (as dextrose) . . . . 433 „ Material soluble in 85 per cent, alcohol .. ..161 „ He describes two kinds of carbohydrates as occurring in the substance : (1) Lichenin, which forms the jelly and yields dextrose on hydrolysis, but is unaffected by digestion and probably does not form glycogen ; and (2) iso-lichenin, which is present in much smaller amount and resembles soluble starch, but on digestion yields only dextrins — no sugar. It is evident from the chemical nature of the substance, from the resistance of its constituents to digestion, and from the small amount of it ever present in a jelly, that its nutritive value must be regarded as practically nil. 1 American Journal of Physiology, 1898, i. 455. [ 27° 1 CHAPTER XV SUGAR, SPICES, AND CONDIMENTS Sugar. The importance of sugar as an article of diet is so great that it may be well to devote a little space to its special consideration. Several different varieties of sugar enter into the composition of articles of diet, but for practical purposes they may be divided into two groups : (i) The sucroses, known chemically as the di- saccharids (C 12 H 22 O n ), the chief examples of which are cane-sugar (sucrose), beet-sugar, maple-sugar, malt-sugar (maltose), and milk- sugar (lactose) ; (2) the glucoses, or monosaccharids (C 6 H 12 6 ), exemplified by grape-sugar (dextrose), fruit-sugar (lasvulose), and invert sugar, which is a mixture of those two, and is best known in the form of honey. We may now consider each of these varieties in some detail. 1. Cane-sugar, or sucrose, is the most familiar of all kinds of sugar. It is most commonly derived from certain special grasses, such as the sugar-cane or sorghum, but occurs also in smaller amount in a great many plants and fruits. When derived from other sources than the sugar-cane, special names, such as beet-sugar or maple-sugar, are usually given to it ; but it must be distinctly understood that these are chemically indistinguishable from the form of sugar derived from the sugar-cane. Cane-sugar has been in use in the world as a food for many ages, but it is only within comparatively recent times that it has been manufactured cheaply enough to take an important place in ordinary diets. The following brief history of its introduction into Europe is taken from a valuable pamphlet on ' Sugar as Food,' issued by the United States Department of Agriculture : x » Sugar from the sugar-cane was probably known in China 2,000 1 Farmers' Bulletin, No. 93, 1899. HISTORY OF SUGAR 271 years before it was used in Europe. When merchants began to trade in the Indies it was brought westward with spices and per- fumes and other rare and costly merchandise, and it was used for a long time exclusively in the preparation of medicines. An old saying to express the loss of something very essential was, " Like an apothecary without sugar." Greek physicians several centuries before the Christian era speak of sugar under the name of " Indian salt." It was called " honey made from reeds," and said to be " like gum, white and brittle But not until the Middle Ages did Euro- peans have any clear idea of its origin. It was confounded with manna, or was thought to exude from the stem of a plant, where it dried into a kind of gum. When in the fourteenth or fifteenth century the sugar-cane from India was cultivated in Northern Africa, the use of sugar greatly increased, and as its culture was extended to the newly-discovered Canary Islands, and later to the West Indies and Brazil, it became a common article of food among the well-to-do. In 1598 Hentzer, a German traveller, thus describes Queen Eliza- beth, then sixty-five years of age : " Her nose is a little hooked, her lips narrow, and her teeth black, a defect the English seem subject to from their great use of sugar." By many the new food was still regarded with suspicion. It was said to be very heating, to be bad for the lungs, and even to cause apoplexy. Honey was thought to be more wholesome, because more natural than the " products of forced invention." ' One of the earliest records of the use of sugar in this country 1 is to be found in the accounts of the Chamberlain of Scotland in the year 1319. Its price at that time was is. g£d. per pound. Since then the consumption of sugar has increased so enormously that each of us in this country now uses between 80 and 90 pounds of it annually. 2 The composition of the sugar-cane and its juice is about as follows: 3 Entire Cane. Juice. Water 7 io 4 794 Sugar 1802 f 196 (crystallizable). 03 (uncrystallizable). Cellulose 9'56 Albuminous matter . . . . 055 0-37 Fatty and colouring matter 0-35 Soluble salts 012 \ Insoluble salts .. .. 016 J- 023 Silica 020 J 1 See Bannister's Cantor Lectures, 1890. 2 Calculated from the total sugar consumption of the United Kingdom. Some of this, however, is re-exported in a manufactured form as biscuits, jam, sweets, etc. , so that it is probably nearer the mark to say that the average amount of sugar consumed daily by each individual in this country is 3 ounces. s Thorpe's ' Dictionary of Chemistry,' 1893, iii. 615. ip FOOD AND DIETETICS In order to separate the sugar, the canes are crushed, and the expressed juice is then bleached by means of sulphurous acid, neutralized with lime, and all albuminous matters coagulated by boiling. It is then filtered, evaporated down, and the uncrystal- lizable sugar (glucose) separated by aid of a centrifuge. In this way the raw sugar is obtained in a crystalline form still mixed with impurities, while the residue is sold as molasses or treacle, or is used to make rum. The chief examples of raw cane-sugar are * Barbadoes,' ' Clayed,' and ' Demerara,' the differences in these depending on the mode of manufacture. ' Barbadoes ' is a very dark sugar, while ' Demerara ' is characterized by a golden colour and well-defined crystal ; it has also a fine flavour, due to its being prepared by the careful treatment of specially selected canes. Raw sugar is purified by the process of refining, which consists in remelting the sugar, filtering it, and clarifying it by means of char- coal. It is then carefully evaporated in vacuo. If loaf-sugar is wanted it is run into moulds. Moulded cube-sugar is made in the form of sticks, and afterwards cut into cubes by machinery. Granu- lated sugars are made in the centrifuge. Other varieties depend on the mode of crystallization and grinding to which the sugar is sub- jected. 2. Beet-sugar. — Fully two-thirds of the • cane '-sugar commonly used is really derived from the sugar beet. The following account of the growth of the industry is derived from the pamphlet already mentioned : ' Marggraf, a chemist, of Berlin, first discovered in 1747 that beets, with other fleshy roots, contained crystallizable sugar identical with that of the sugar-cane. In 1796 Marggrafs pupil, Achard, erected the first manufactory for beet-sugar, and in 1799 he brought the subject before the French Academy. He manufactured beet- sugar on his farm in Silesia, and presented loaves of refined beet- sugar to Frederick William III. of Prussia in 1797 ; but the 2 to 3 per cent, of sugar that could be extracted by the methods then in use was too small for commercial success. A new stimulus was given by the sugar bounties of Napoleon in 1806, and methods were rapidly improved, especially in France. Two great difficulties were still to be met : the percentage of sugar present in the beet was small (6 per cent.), and it was separated with great difficulty from the many non-sugar constituents, some of them acrid and of very unpleasant taste. Science now came to the rescue, and a beet was gradually developed having a larger percentage of sugar and a smaller percentage of the undesirable impurities. Barber says that CANE-SUGARS 273 in 1836 18 tons of beetroot were necessary to produce 1 ton of sugar ; in 1850 this quantity was reduced to I3'8, in i860 to 127, tons ; and in 1889 to 9/25 tons. From 6 per cent, of sugar, as found by Marggraf, the sugar beet of good quality now contains 15 per cent, and more, 12 per cent, being considered necessary for profitable manufacture.' The sugar is extracted from the beets by rasping them to a pulp, extracting and evaporating in vacuo, with subsequent decoloration by means of animal charcoal. To the ordinary consumer beet-sugar is hardly distinguishable from that derived from the sugar-cane, and it has already been stated that to the chemist the two are really identical. 1 There is no evidence for the statement sometimes made, that beet-sugar is more injurious to health than genuine cane-sugar ; but I am informed by manu- facturers that for some purposes sugar derived from the cane is preferable, e.g., in the manufacture of fruit syrups and British wines. It is said to be less liable to fermentation. 3. Maple-sugar is derived from the sugar maple of North America by tapping the bark in early spring and allowing the sap to escape as it flows upward. The sap is evaporated and the sugar allowed to crystallize out while the residue is used as maple syrup. One maple-tree yields about 4 pounds of sugar in a season. There is no chemical difference between maple-sugar and that derived from the cane or beet, but it contains certain ethereal sub- stances and organic acids which give it its peculiar flavour. It is probably on the presence of these that the slightly laxative qualities of maple-sugar depend. As a commercial source of sugar the maple cannot compare with either the cane or the beet, and maple-sugar is now chiefly used as a luxury and for the sake of its agreeable taste. The average composition of these sugars in their raw state is as follows : 2 Source. Water. Cane-sugar. §£j£*£ t Ash. Sugar-cane.. .. 216 Sugar beet . . . . 2'go Maple . . . . — After being subjected tc the process of refining, sugar is practically a pure chemical substance. It is indeed ' the purest food-substance in commerce ' (Wynter Blyth). 1 It has been aptly remarked by a writer in the British Medical Journal (1901, i. 1119). that the difference between cane-sugar and beet-sugar is ' not a chemical but a physiological one — a question of taste and flavour. It is a difference similar to that between vin ordinaire and Chateau Margaux, and between silent spirit faintly coloured and genuine Scotch whisky.' 8 ' Sugar as Food,' p. 12. IS 93 33 424 127 92'00 259 256 8280 274 FOOD AND DIETETICS 4. The remaining sugars of this group are malt-sugar, or maltose, and milk-sugar, or lactose. Both of these, though disaccharids, differ very considerably in chemical and physical properties from the sugars we have been considering. Milk-sugar has already been described (p. no), and we may defer the study of maltose until we come to malt-extracts (p. 566). v Certain substances derived from cane-sugar deserve brief men- tion. When strongly heated, sugar melts into a yellowish liquid, and undergoes some physical- alteration, so that on cooling it does not crystallize, but forms a transparent, brittle mass, familiar to everyone as barley sugar. If heated to a still higher temperature its colour darkens, and it acquires a bitter taste, the product being caramel, which is so largely used in cooking operations. Treacle, molasses, and golden syrup are produced as by-products in the manufacture of crystallized sugar. Their syrupy consistence is in part due to the fact that the impurities which they contain prevent the cane-sugar from crystallizing, and partly also to their being fairly rich in uncrystallizable fruit-sugar. The following represents their composition : West Indian q. , Golden Molasses. lnacu - Syrup. Cane-sugar 470 32-5 390 Fruit-sugar 20-4 37-2 33-0 Extractive and colouring matter.. 27 3-5 28 Salts 2-6 34 2-5 Water 27-3 23-4 227 It is interesting to compare the proportion of nutritive matter in these with that in malt-extract (p. 566), but to this subject we shall return later. 5. The other great group of sugars is the glucoses, or mono- saccharids. The best example of these is dextrose, which occurs so abundantly in the grape. When grapes are dried to form raisins, the dextrose separates out, and may be recognised in the raisins in the form of little yellowish-white granular masses. Commercial glucose is usually got by boiling starch with acids. It occurs in a syrupy form. When heated it turns brown, and is used in cookery as ' sugar colouring.' Mixed with egg-albumin, it is largely employed in the preparation of ' icing ' and ' fondants ' in confectionery and in the manufacture of bonbons. Fruit-sugar, or lsevulose, is found, as its name implies, in most fruits. It is characterized by being almost uncrystallizable. It is hardly ever met with in an isolated form in dietetics, but is some- times administered to diabetic patients, by some of whom it is better borne than any other form of sugar (p. 498). CANE SUGARS 275 Invert sugar is a mixture of dextrose and lsevulose. It can be prepared from cane-sugar by the action of ferments or by simple boiling, but more readily by boiling with acids. This ' inversion ' of cane-sugar, as it is called, goes on pretty rapidly when cane- sugar is boiled with fruit-juice, the active agent being the vegetable acid of the fruit. Thus, a large proportion of the cane-sugar used in making jam is converted into invert sugar in the process. It is important to remember also that invert sugar does not crystallize. Honey is the most familiar form of invert sugar. It contains about equal parts of dextrose and lffivulose, its flavour being due to the presence of small amounts of volatile substances derived from the flowers. The mean composition of pure honey was found by Dr. Sieber to be as follows : Moisture 1998 per cent. Grape-sugar (dextrose) 3471 ,, Laevulose.. .. .. .. .. 3924 „ Substances other than sugar .. .. 502 „ The comb consists of fatty substances, which are probably in- capable of digestion. There is a form of artificial honey in which the comb consists of paraffin wax and the fluid part of commercial glucose, and the latter is often used also for the adulteration of dripped honey. Its use can be detected by the presence of an excess of dextrose in the mixture. Such an artificial product is quite innocuous, but, being much cheaper to produce than the genuine article, it should not be sold at the same price. The basis of sweetmeats is either cane-sugar or one of the glucoses. Sugar-candy is one of the purest. It consists of cane- sugar which has been allowed to crystallize round threads. It contains about 20 per cent, of water and 80 per cent, of crystal- lizable sugar. Toffee consists of melted sugar and butter in almost equal propor- tions. Everton toffee has about 34 per cent, of cane and 27 per cent, of invert sugar, which has been derived from cane-sugar by the prolonged boiling. It is a highly nutritious substance, and makes an agreeable substitute for ' cod-liver-oil and malt ' in the case of ill-nourished children. Chocolate contains about 45 per cent, of cane-sugar, but no dextrose or laevulose. The rest of it is composed of cocoa-powder. (For analyses, see p. 328.) Invert sugar, or a mixture of glucose and albumin, is largely used in the preparation of uncrystallized sweets, such as the creamy matter in the interior of chocolate drops. 18—2 276 FOOD AND DIETETICS The colouring of sweets is derived either from burnt sugar of from one of the anilin dyes, most commonly eosin. Cochineal is also a favourite colourer. It is interesting to note that aniline dyes may be excreted in the urine almost unchanged, and cases are on record where patients have been supposed to be passing blood, when they had merely been sucking red sweets. There is no reason to suppose, however, that such substances are in any way harmful to life. Jams consist essentially of fruit preserved in a strong solution of sugar. We have already seen that the acids of the fruit, aided by the high temperature employed in the course of preparation, bring about the conversion of a considerable proportion of the cane-sugar into the invert form. Home-made jam is boiled for a longer time than the commercial article, and consequently contains more invert and less cane-sugar than the latter. Aitchison Robertson 1 gives the proportion of cane-sugar in most home-made jams as 20 per cent., while commercial jams have anything from 10 to 50 per cent. In some home-made jams which he examined the proportion of cane- sugar which had been inverted was as follows : Proportion of Cane-sugar inverted. Strawberry .. .. .. two-fifths Raspberry three-fifths Blackberry four-fifths Marmalade five-sixths Plum . . . . . . . . six-sevenths The importance of these figures is derived from the fact that the larger the proportion of cane-sugar which has been inverted, the less likely is the jam to interfere with digestion (see p. 278). Commercial glucose, on account of its incapability of crystallizing, is often used to make jam from inferior fruit or from the remains of fruit, the juice of which has been used to make fruit syrups and jellies. Such jam may have a good appearance, but is deficient in fruit flavour. It is, however, quite wholesome and nutritious. The gelatinizing power of jellies is due to the presence of pectin in the fruit (p. 255). If boiled too long, the power of gelatinizing is lost, and a syrup results instead of a jelly. In commercial jellies gelatin is sometimes added to prevent this. Almost half the weight of any given quantity of jam is made up of sugar in some form or another. The nutritive value of jam has already been considered (p. 137). 1 ' The Value of Saccharine Foods as Articles of Diet,' Scottish Medical and Surgical Journal, 1898, iii. 30. DIGESTIBILITY OF SUGARS *77 Digestion of Sugar. The first factor which determines the digestibility of a sugar is its chemical form. No matter in what form sugar is consumed in the food, it can only be assimilated as a monosaccharid (dextrose or Iffivulose). Hence, we find that provision is made in the alimentary canal for the conversion, by means of suitable ferments, of all forms of sucrose (disaccharids) into dextrose and lavulose ; i.e., they are inverted. It is evident, then, that from a dietetic point of view we may speak of the sucroses as undigested and the glucoses as pre- digested sugars. It now becomes clear why sweet fruits are such important dietetic sources of sugar. It is because they contain the latter in a form in which it is fit for direct absorption into the blood. For the same reason honey must be regarded as a very easily digested saccharine substance, and the importance of the inversion which cane-sugar undergoes in the manufacture of jams also be- comes manifest. The superiority of home-made over commercial jams is also set in a clearer light by reference to these considerations. The second factor which influences the digestibility of a sugar is the degree of concentration of its solution. In strong solution sugar is an irritant to the tissues. In contact with the skin, it is apt to set up superficial inflammation. This is familiar in the form of the eczema which is apt to appear in diabetics from the contact of the sugar- containing urine with the skin, and from the similar condition occurring on the arms of grocers and other persons who have frequently to handle sugar, and it is on account of its irritating properties that sugar cannot be used as a subcutaneous aliment, though otherwise well adapted to fulfil that function. All attempts to use it in that fashion have been frustrated by the pain which it sets up (see p. 577). The same is true of the stomach. Brandl, experimenting on dogs, found that a 5-7 per cent, solution of sugar produced reddening of the mucous membrane ; if the concentration was increased to 10 per cent., the mucous membrane became dark red, while a 20 per cent, solution produced pain and great distress. This irritating effect on the mucous membrane is accompanied by the production of much mucus and the pouring out of a highly acid gastric juice. These irritating effects seem to be much more pronounced in the case of cane-sugar than in that of the glucoses. Aitchison Robertson 1 injected 250 c.c. of a 20 per cent, solution of 1 ' Digestion of Sugars in Some Diseased Conditions of the Body,' Edinburgh Medical Journal, 1894, x '-> P*- •• 49^- *7% FOOD AND DIETETICS cane-sugar into the stomach of a patient who was suffering from chronic gastric catarrh. Shortly afterwards the patient felt sick, and vomited a very acid fluid which put his teeth on edge. He complained also of heart-burn and flatulence, and of severe pain in the region of the stomach. A solution of invert sugar of the same strength produced no discomfort. The experiment was repeated with similar results in other cases of dyspepsia. The invert sugar produced no unpleasant symptom, and disappeared rapidly from the stomach, while the cane-sugar caused much distress, and remained for a long time. The greater digestibility of invert sugar is here brought out again in great clearness. Cane-sugar may easily interfere with the diges- tion of other foods, by reason of the great outpouring of mucus in the stomach which its presence induces. Schtile 1 found that 10 to 30 grammes (2 to 6 lumps) of cane-sugar, when taken with an ordinary test breakfast, produced no appreciable effect on its diges- tion; but when the quantity was increased to 120 grammes consider- able delay of digestion ensued. Seeing, he says, that one can easily take 80 to 100 grammes of sugar at dessert in the form of ices and sweets, a retarding action on the digestion of a meal must not unfrequently be manifested. Experiments by Ogata on dogs confirm these results. 2 It is evident from all this that, if we wish to avoid the risk of interfering with digestion by the use of sugar, care should be taken that the latter is not consumed in a concentrated form, but that the comparative dilution in which sugar occurs in natural foods, such as fruits and milk, is imitated. This is of special importance in the case of dyspeptics, and the superiority of glucose for such patients over ordinary cane-sugar cannot be too strongly insisted upon. Another matter affecting the behaviour of different sugars in the stomach is their tendency to undergo fermentation. Three varieties of such fermentation may be distinguished : (1) Alcoholic, resulting in the production of alcohol and acetic acid ; (2) butyric, with the formation of butyric acid ; (3) lactic, the product being lactic acid. Now, it is interesting to note that different sugars vary in the readi- ness with which they tend to undergo these different forms of fermentation. Some interesting experiments upon this point have been carried out by Aitchison Robertson. 3 He arranges the sugars 1 Zeit. f. Klin. Med., i8g6, xxix. 49. 2 ' Sugar as Food,' p. 22. 3 ' Rate of Fermentation of Sugars,' Edinburgh Medical Journal, 1894, xxxix., pt. ii. 803. ASSIMILATION OF SUGARS 279 in the following order, according to the rapidity with which they tend to undergo each variety of fermentation : Lactic. Butyric. Alcoholic. Lsevulose (most fer- Lsevulose (most fer- Maltose (most fer- mentable), mentable). men table). Lactose. Maltose. Invert sugar. Dextrose. Dextrose. Cane-sugar. Invert sugar. Invert sugar. Dextrose. Cane-sugar. Cane-sugar. Laevulose. Maltose. Lactose. Lactose. The practical deductions which he draws from his observations are these : 1. In dyspepsia the absorption of carbohydrates is delayed, and therefore all sugars tend to ferment. 2. In dyspepsia with lactic acid formation, one should avoid dextrose, lsevulose and invert sugar, and use cane-sugar, maltose and lactose in moderate amount. 3. In butyric fermentation lactose should be preferred. 4. In alcoholic and acetic fermentation one should forbid invert sugar and kevulose, and give lactose. It will be observed that, of all sugars, lactose is least liable to fermentation. This is another point in favour of the value of a milk diet in stomach complaints. The last point connected with the influence of sugar on the digestive organs is its supposed injurious effects on the teeth. The impression that sugar-eating is bad for the teeth is so widespread that one can hardly suppose it to be devoid of all real basis. It must be admitted, however, that the supposition is not supported by any very conclusive observations. If sugar does destroy the teeth, it probably does so indirectly by lingering in the crevices of the mouth, and leading to the production of acids which eat away the enamel. Assimilation of Sugars. The fate of sugar after entering the blood is to be converted by the liver into glycogen. What becomes of it after that is still disputed, but everyone is agreed that glycogen is the form in which sugar is stored in the body, for a time, at least. Now, it has been found by physiological experiment that it is not all sugars which are capable of being converted into glycogen. It is only those which can be directly fermented by yeast — fermented, that is to say, without being first changed into invert sugar. 1 Of the sugars commonly 1 See Cremer, Zeit. f. Biologic, 1892, xxix. 484, and 1895, xxxii. 49; also Fritz Voit, Deut. Archiv. f. Klin. Med., 1897, lviii. 523, and Achard and Weil, Archives de Med. Expir., 1898, x. 816. 28o FOOD AND DIETETICS consumed, cane-sugar and lactose are not directly fermented by yeast, and, in order that they may be stored up as glycogen, provision has to be made for their previous inversion. This is met, as we have seen, by the production of certain inverting ferments in the intestine which act on these sugars. If, however, these ferments happen, in any particular case, to be of feeble activity while the absorptive power of the intestine is great, some of the sugar may reach the blood unchanged, and, being incapable of conversion into glycogen, straightway appears in the urine. Even in the case of the directly fermentable sugars, if a large quantity is absorbed in the course of a short time, the glycogen-forming power of the liver may be unable to keep pace with the demands made upon it, and some of the sugar will appear in the urine. There results from this what is termed alimentary glycosuria. By giving large quantities of a different sugar on an empty stomach, and observing whether or not glycosuria results, one has been able to determine what may be called the assimilation limit of each — that is to say, the maximum quantity which can be consumed at one time without the overflow of any of the sugar into the urine taking place. These maximum amounts are about as follows : For lactose .. .. .. 120 grammes. For cane-sugar .. .. 150 to 200 grammes. For laevulose . . . . 200 grammes. For dextrose . . . . 200 to 250 grammes. Lactose, therefore, is the least assimilable of all sugars, and if taken in excess is the most likely to result in the production of glycosuria. It must further be borne in mind that the assimilation limit is not the same for all individuals. Some people are able to convert more sugar into glycogen than others. It has been stated that persons with a low assimilation limit are potential diabetics ; that is to say, they are more liable than others to become the victims of diabetes mellitus. There is another chemical fact relating to the assimilation of sugars which is of some practical interest, and it is this : Experi- ments have shown that the only sugars capable of direct fermenta- tion, and therefore of conversion into glycogen, are those which contain either three carbon atoms or a multiple of that number. Those which contain five, seven, or any other number of carbon atoms cannot be converted into glycogen, and accordingly, should they gain access to the blood, are at once excreted in the urine. Now, sugars with five carbon atoms (pentoses) occur with con- siderable frequency in certain fruits, and hence pentosuria, as it is NUTRITIVE VALUE OF SUGAR 281 termed, is a not infrequent result of the free consumption of such foods. Notwithstanding all this, it must be noted that, if sugar be taken along with other food, and distributed uniformly over the day, very large quantities can be consumed without the danger of exceeding the assimilation limit. Vaughan Harley was able to take a pound of cane-sugar daily — with injurious results as regards his digestion, it is true, but without producing glycosuria. As a general rule, one may assume that \ pound can be taken daily without any bad results at all, but the exact amount must of necessity depend to a large extent on the muscular activity of the subject. Nutritive Value and Economy of Sugar.i We have seen that refined sugar is to be regarded as a practically pure carbohydrate. That being so, its food value must be high, for every gramme of it will yield 4*1 Calories of energy. An ordinary lump of loaf-sugar weighs 5 grammes, and yields therefore fully 20 Calories. Four such lumps contain as much carbohydrate as a medium-sized potato. It is evident from these considerations that even the amount of sugar ordinarily added to a cup of tea may contribute in no small degree to the supply of energy required by the body daily. A pound of butter will yield about twice as much energy as a similar weight of sugar, but at nearly four times the same cost, for sugar is one of the cheapest fuel foods — perhaps the cheapest — which we possess, a shilling spent on it yielding 11,000 Calories, or more, even, than can be obtained in the form of bread for a similar expenditure. This great cheapness of sugar is a development of recent years, and can hardly be without far-reaching effects on the national health. It tends to make us consume more carbohydrate and less fat, for fat is always a dear form of food. Whether this is an advantage it would be difficult to say. It is true that sugar can replace fat as a fuel in the proportion of 7.\ parts of the former to 1 of the latter, but it does not follow on that account that sugar can perform all the functions in the body which are usually fulfilled by fat, provided that proportion be observed. We have already learnt (p. 22) that sugar is more rapidly burnt up in the body than fat, and is on that account a more efficient proteid-sparer than the latter. This rapid oxidation 1 For an interesting discussion on this subject see a paper by Dr. H. Wil- loughby Gardner (' The Dietetic Value of Sugar ') in the British Medical Journal, J901, i. 1010. 282 FOOD AND DIETETICS is favoured by the ease with which sugar is absorbed, and, interfering as it does with the complete destruction of proteids, probably explains the bad effects sometimes observed from the use of sugar in gout and gravel (p. 517). The relative advantages of fat and sugar as fat-formers is another unsettled point. The highly fattening proper- ties of sugar are undoubted ; it is probably not only itself capable of being transformed into fat, but spares the body fat and part of that in the diet from combustion ; but whether the fat so formed is as useful as that which can be stored up from the fat in the diet is a question which physiology is not yet in a position to solve. The point is one of some practical importance in the feeding of con- valescents, and in the selection of cod-liver-oil or malt as a fattening agent. Of this, however, there can be little doubt, that the great cheap- ness of sugar must have a favourable influence on the health and growth of children, for it ensures to them an ample supply of the body fuel which they so much need, and which the dearness of fat is apt to make unattainable. It has the advantage, too, of being a form of fuel which few children are likely to refuse, and that is far from being true of fat. 1 It is as a muscle food, however, that sugar is of special importance. We have already learnt (p.' 37) that the carbohydrates are probably the chief source of muscular energy, and the sugars, on account of the ease and rapidity of their absorption, are better calculated to fulfil this function than any other member of the carbohydrate group. It is interesting to note that Brillat-Savarin pointed out long ago that ' the English give sugar to their blood horses in order to sustain them in the trials to which they are subjected.' To Swiss guides and Arctic explorers, too, the value of such a saccharine food as chocolate has long been familiar. It was not until the year 1893, however, that Mosso first put the value of sugar as a muscle food to the test of experiment. By means of the ergograph he was able to show that sugar has a notable effect in lessening muscular fatigue. 1 On the other hand, Bunge has uttered a warning note regarding the dangers incidental to the great increase in the dietetic use of sugar in recent times (' Der Wachsende Zuckerconsum und seine Gefahren,' Zeit. f. Biolqg., 1901, xli., p. 155). He points out that sugar, if largely eaten, must diminish the amount of other vegetable foods in the diet, whence there may result a deficit in the supply of calcium, iron, fluorine, and other mineral ingredients to the blood. This may tend to produce anaemia and caries of the teeth. He is of opinion that it is always dangerous to replace natural foods by pure isolated chemical products. I think it is not unlikely, too, that the greater consumption of sugar in recent years may have something to do with the increasing commonness of diabetes which many believe to exist. SUGAR AS A MUSCLE FOOD 283 The subject was then taken up by Vaughan Harley, who found, working under Mosso's direction, that if he took 17J ounces of sugar a day his power of doing work was increased 61 to 76 per cent. He showed also that the administration of sugar delays the onset of fatigue, and that its effects are rapidly exerted, the maximum influence being reached in about two hours. Schumburg 1 was able to confirm these results as regards extraordinary muscular exertion. Similar experiments have recently been performed by Prautner and Stowasser, 2 who found that when sugar was added to their diet their power of doing work was increased, while fatigue and nitrogenous waste were lessened. They conclude that sugar is a specially valuable food for persons who have to perform a single muscular effort, and especially if they are obliged to do so in a state of exhaustion. The results of these scientific experiments, which were carried out with due regard to all possible sources of fallacy, have led to an extensive practical trial of sugar as a food for persons engaged in muscular labour. Two examples may be mentioned. During the autumn manoeuvres of the German army a few years ago, a number of the men were given ' ten lumps of sugar daily, in addition to their ordinary rations. The trial extended over five weeks, and it was found that the soldiers who had been supplied with sugar marched better and suffered less from hunger, thirst, and fatigue than their fellows who were not so supplied. As a result of the experiments, the surgeon in charge recommended that the sugar ration for soldiers should be raised to 60 grammes per day (about 2 ounces). The other example illustrating the practical value of sugar as a muscle food is to be found in the experience of certain rowing clubs in Holland. They found sugar to be a very valuable food in training. The rowers who used it always won, on account of their superior powers of endurance, and it seemed to counteract the bad effects of an exclusively meat diet, so that the men did not become 'stale.' * One case, as given in detail, is very interesting. Two schoolboys, seventeen and nineteen years of age, with only two hours a day for practice, at the end of two months entered for the rowing races. No change had been made in their diet except that they ate as much sugar as they wished, sometimes as much as one-third of a pound at the time of their daily exercise. One of them, however, 1 Archiv. f. Anat. und Physiol., 1899, Sup. Bd., p. 2S9. a Centralb. f. Inn. Med., 1899, xx. 169. 2 8 4 FOOD AND DIETETICS did not make this addition to his diet until the third week, when he began to show all the signs of overtraining — loss of weight, and a heavy, dull feeling, with no desire for study. On the third day after beginning the use of sugar these symptoms disappeared. At the time of the race both youths were in fine condition, and were victorious over their antagonists, who did not believe in the use of sugar. No bad after-effects were observed.' 1 Additional evidence in favour of the free use of sugar in training and during the performance of hard muscular work has been brought forward by Steinitzer. 2 He has found from personal experience in Alpine climbing that his capacity for exertion is much greater when he partakes largely of sugar, whilst at the same time fatigue is lessened. The sugar is best taken in solution in quantities of from 5 to 10 ounces spread over the day. It may be dissolved in tea, wine and water, or lemonade. As much even as 20 ounces may safely be taken for several days on end during hard exercise without the least harm. It certainly seems as if it would be worth the while of captains of football teams to try the effect of serving round small cups of black coffee, strongly sweetened with sugar, at ' half-time,' instead of the usual lemon. They would probably be rewarded by the greater endurance of their men in the second half of the match. Spices and Condiments. The spices, condiments, and flavouring agents generally, are not, as a rule, foods in the strict sense of the term ; that is to say, they are not capable of supplying the body with building material or energy. None the less, however, they are essential constituents of the diet. Their importance rests upon the power which they possess of improving appetite, and, by so doing, of increasing the digestive power. To the healthy man of vigorous appetite their presence is less essential. It has been found by experiment that meat from which all the flavouring ingredients have been extracted by prolonged boiling is as well digested by healthy men as fresh meat itself, 3 in spite of the fact that it was eaten with but . little relish. To persons of jaded appetite, however, and to invalids and con- valescents, the flavouring agents of the food are very powerful aids 1 ' Sugar as Food,' p. 18. 8 ' Die Bedeutung des Zuckers als Kraftstoff,' etc. (Berlin, Paul Parey, 1902). 8 Pettenkofer and Ziemssen's ' Handbuch,' Part I., p. 94, 1882. SPICES AND CONDIMENTS 285 to digestion, and no adjustment of the diet in such cases can be regarded as satisfactory which leaves this consideration out of account. Their presence justifies the inclusion in the regimen of many substances which are otherwise of little nutritive value, such, for example, as beef-tea. The experiments of Pawlow 1 have placed the mode of action of these substances in a clearer light, and tend to enhance our sense of their importance. They appear to act partly through the organs of taste, in part reflexly, and in part also by a direct local action on the stomach. In all of these ways the appetite is aroused and the secretion of gastric juice promoted. 2 The direct irritant effect which some of them have upon the stomach contra-indicates their use in certain forms of dyspepsia in which the mucous membrane is in a state of congestion or slight catarrh. Many of them, too, exert a similar influence upon the organs of excretion, and for that reason they should be avoided by patients who are suffering from conges- tion of the kidneys or nephritis, or, indeed, inflammation in any part of the genito-urinary tract. We have not space to study in detail the chemistry and composi- tion of the vast number of flavouring agents which enter into the diet. It will be sufficient for us to glance for a moment at some of those in commonest use. Mustard is derived from the seeds of the black or white mustard- plant (Brassica nigra and alba). The seeds of the white plant are the larger. They contain an acrid principle, but no essential oil. The black seeds contain a substance called myronate of potash, along with a ferment (myrosin), and these, when moistened with water, interact, producing the pungent' essential oil to which the character- istic sharpness of mustard is due. The horse-radish (Cochlearia armoracia) contains an oil similar to that of black mustard. Mustard flour contains from 15 to 25 per cent, of fixed oil, 0*5 to 2 per cent, of volatile oil, 35 to 45 per cent, of nitrogenous matter, 2 to 5 per cent, of cellulose, and 4 to 6 per cent, of mineral matter, along with a little starch (Snyder). Black pepper is derived from the unripe berries of the Piper nigrum ; white pepper is produced from the ripe fruit. The seeds contain an 1 'Die Arbeit der Verdauungsdriisen,' Wiesbaden, 1898, chapter viii. 2 More recent experiments on men have shown that the effect of spices on the secretion of gastric juice is very variable and inconstant, and probably depends to some extent on factors which vary in different individuals. On the other hand, their power of stimulating the movements of the stomach is invariable (see v. Korczynski, ' Ueber den Einfluss der Gewiirze auf die Sekretorische und motorische Tatigkeit des Magens,' Wiener Klin. Wooh. , 1902, xv. 468). 286 FOOD AND DIETETICS essential oil and an alkaloid (piperine), both of which contribute to the pungent taste of the substance. Cayenne pepper is derived from the pods of capsicum ; the small pods constitute chillies. The basis of vinegar is acetic acid. Every ioo c.c. of good vinegar should contain 5 grammes of the acid, calculated in the glacial form. In genuine vinegars the acetic acid is produced by the oxidation of alcohol by a fungus (the Mycoderma aceti), while in wood vinegar it is produced by the destructive distillation of wood, the product being often coloured by the addition of burnt sugar. The source of the alcohol in genuine vinegars varies. In the best varieties weak wines are the source, and such vinegars retain a certain amount of ' bouquet,' derived from the wine. Solutions of alcohol derived from the fermentation of malt — dilute beers, in fact — are, or ought to be, the source of malt vinegar ; but this term is often used by manufacturers in a very misleading fashion, for in recent years dilute spirit derived from sugar or molasses has come much into use as a substitute for malt. It can scarcely be main- tained that such a substitution is in any way injurious to health. Vinegar is often distilled, in order to make it keep better. The distillate contains the acetic acid, along with traces of alcohol and ether. This variety is said to be very popular in Scotland (Allen). In addition to being a condiment, vinegar has an important action in softening the fibres of hard meat and the cellulose of green vege- tables. Hence its use with such articles as crab and its addition to salads. Although the acetic acid which vinegar contains is ulti- mately oxidized in the body, with the production of alkaline com- pounds, there is still reason to believe that it has an unfavourable influence in gout, and may even precipitate an attack if freely in- dulged in. Ginger is the root of a plant (Zingiber officinale) met with chiefly in India. It contains from 1/5 to 3 per cent, of volatile oil, and about 3 per cent, of fixed oil, along with a large amount of starch. Cinnamon and Cassia are derived from the bark of several species of tropical plants. They contain volatile and fixed oils. Cloves are the dried flower-buds of a tropical evergreen. They contain as much as 10 per cent, of volatile oil and a good deal of tannin. Allspice, or pimento, is the fruit of a West Indian evergreen, which contains about 2-5 per cent, of volatile oil. Nutmeg is the kernel of a small pear-like fruit which grows in the East Indies. Mace is the red fleshy mantle which envelops the seed. SPICES AND CONDIMENTS 287 These contain about 25 per cent, of fixed and 2*5 to 5 per cent. of volatile oils. It only remains to add that sugar itself, in addition to its value as a food, is one of the most important of the condiments in common use, and, like all of these, is able to stimulate appetite and digestion if used in moderation. This justifies the consumption of sweets at dessert. Chemical substitutes for sugar which possess its flavouring qualities without its food value are saccharin (benzoic sulphamide) and dulcin (sucrol). The preparation known as saxin owes its sweetness to saccharin. Porcherine is another powerful artificial sweetener. These have many hundred times the sweetening power of sugar, but are of no use as foods. They are used tr> replace sugar as a flavourer, chiefly by diabetic, gouty, and obese patients. 1 28S J CHAPTER XVI MINERAL CONSTITUENTS OF THE FOOD The human body contains about 7 pounds of mineral matter, of which about five-sixths is in the bones. An analysis of the whole body would yield about 5 per cent, of ash. It is obvious from this that the mineral ingredients of the diet are important building material for the body, and are therefore to be regarded as foods in the strictly scientific sense of the term. The chief mineral substances required in the food are sodium, potassium, calcium, magnesium, and iron, along with phosphorus, chlorine, sulphur, and traces of silica, fluorine, and iodine. So necessary are these for maintaining intact the fabric of the body that death ensues within about a month if the supply of them is entirely cut off, even although all the other constituents of a normal diet are supplied as before. Recent estimates of the amount of some of the chief mineral ingredients of the diet required per day are as follows : Grammes. Grammes. Phosphoric acid . . . . 3 to 4 Calcium oxide . . .. 07 to 1 Sulphuric „ . . •• 2,, 3J Magnesium oxide .. 0-3 ,, 0-5 Potassium oxide . . .. 2 ,, 3 Chlorine 6,, 8 Sodium ,, .. .. 4.. 6 It being granted, then, that the mineral constituents of the food are important as tissue-builders, the question may next be asked, Are they of any value as sources of heat or energy ? As regards the former, the reply is in the negative. The mineral substances in the food enter the body in a form too highly oxidized to be capable of yielding any heat in the tissues. As regards the question of supplying energy, the reply is more doubtful. It is true that the substances under consideration cannot yield energy by oxidation in the way that the proteids, fats and carbohydrates do, but there is reason to believe that they are able to act indirectly as sources of energy in virtue of the osmotic properties MINERAL CONSTITUENTS OF THE FOOD 289 which they possess. It is found, 1 for example, that ordinary soup, by reason of its salts, possesses an osmotic pressure of from 7 to 9 atmospheres. Now, the body fluids have an osmotic pressure of only 6 atmospheres, and thus half a pint of soup will raise the osinoiic pressure in the body by fully half an atmosphere. In this way absorp- tion and the diffusion of the body fluids is aided, and such an action is equivalent to the supply of a certain amount of energy to the body. Thus it is that the mineral constituents of the diet may claim to rank as ' foods ' on two grounds : they are builders of tissue and they are sources of potential energy as well, We have next to inquire, What amount of mineral matter must be supplied to the body daily ? To this inquiry no definite reply is forthcoming. We cannot tell how much of these substances is required for healthy nutrition in as precise a manner as we can calculate the need for carbon or for nitrogen, mainly for this reason — that many of the waste mineral matters of the body are excreted by the intestine, and we have no means of telling what proportion of these has merely escaped absorption, and how much has been excreted from the blood after playing a part in metabolism. This, however, one can say, that the amount of mineral matter found in an ordinary mixed diet is sufficient — nay, much more than sufficient — for all the needs of the body, and that amount is about 20 grammes, exclusive of such arbitrary additions as salt. 2 As regards the form in which the mineral constituents enter into an ordinary diet, it may be said that many, if not, indeed, most of them, are in a state of organic combination. Thus, we find calcium and phosphorus organically combined in milk, iron in yolk of egg and in meat, sulphur in all proteid-containing foods, and so on. It would appear, although the reason for it is obscure, that such organic mineral compounds are of special value in nutrition. It cannot be maintained, however, that it is only in such forms that mineral matter can find access to the blood. Experiment has shown that even such a substance as carbonate of lime is absorbed to some extent, for its administration is followed by an increased excretion of calcium in the urine, 3 and the success which attends the treatment of cases of chlorosis by purely inorganic preparations of iron compels us to believe that the metal is capable of being absorbed in that form. 1 Koeppe, 'Die Bedeutung der Salze als Nnhrungsmittel ': 68ten Versamm. Deut. Naturforscher und Arzte. Frankfurt, i8g6, Teil ii., Halfte ii., p. 80. 2 Bunge is of opinion that lime and iron are the only mineral ingredients of the diet which are ever likely to be present in too small amount {Zeit. f. Biolog., 1904, xlv. (N.F., 27), p.532). 8 Strauss, Zeit.f. Klin. Med., 1897, xxxi. 493. 290 FOOD AND DIETETICS Notwithstanding these facts, it was found by Lunin that mice fed on desiccated milk lived quite healthily, whereas other mice which were given pure casein plus all the salts of milk in an inorganic form died. 1 No explanation of such results can be given, but they show that the form in which the mineral constituents of the food are presented to us is by no means a matter of indifference. We may now pass on to consider the amount and kind of the mineral constituents met with in different articles of diet. It would serve no useful purpose, however, to present the reader with analytical tables professing to exhibit the precise percentage of the various components of the ash of different foods, for the reason that these are subject to very great fluctuations in kind and amount. This is specially true of vegetable foods, on the mineral ingredients of which the mode of cultivation and nature of the soil have such a marked influence. It will be more useful to take up the principal mineral substances required by the body separately, and to point out in general terms what articles of diet are richest in them. Let us begin with calcium. Calcium. — It has been calculated, from analyses of human milk, that an infant requires about \ gramme (5 grains) of lime daily. The adult, owing to cessation of the growth of the bones, requires less. Deficiency of lime in the food of an infant leads to softening of the bones ; but this, though an element in rickets, is not really the root of that disease, for nothing is more certain than that an infant may suffer from rickets even although there has been an actual excess of lime salts in its food. In later life various pathological conditions have been ascribed to an excessive consumption of calcium in the food. Amongst these are calculus, atheroma 2 and other calcareous degenerations, and habitual constipation. It must be admitted, however, that there is but little real evidence for such views. It is exceedingly doubtful whether the intestine ever absorbs more of any mineral substance than the tissues require, and if there is a tendency to the accumula- tion of such substances in any particular situation, the fault must be ascribed to some local change in the tissues, rather than to any undue increase of absorption. Of common articles of diet, the richest in calcium is milk. It contains i£ grammes of lime in every litre ; or, put otherwise, there is more lime in a pint of milk than in a similar quantity of lime- 1 See also Socin, Zeit. f. Physiolog. Chem., 1891, xv. 93. 2 See Rumpf, Berliner Klin. Wochensch., 1897, xxxiv. 265. The author recom- mends atheromatous subjects to adopt a diet poor in calcium salts, such, for example, as bread, fish, meat, apples and potatoes. LIME 291 water. Next to milk come eggs, then the cereals — and especially rice — and then some vegetables, such as radishes, asparagus and spinach. Hard waters also must be regarded as important dietetic sources of calcium. Foods poor in lime are meat (but only if derived from a fully- grown animal — veal, for example, being comparatively rich in calcium 1 ), fish, bread, fruits and potatoes. The importance of milk and eggs as foods for growing children will be apparent from these facts, while if one should for any reason desire to construct a dietary containing a minimum of lime, it would be well to draw its ingredients from the members of the second group. Magnesium is usually present in foods in the same proportion as calcium. There are exceptions to this rule, however, for in milk magnesium is less, and in meat rather more, abundant than calcium, while in bread there is actually five times as much of the former as of the latter. 2 Iron is one of the mineral constituents of the diet of which one may say that it is always present in an organic form. It is also mainly excreted in the faeces, and this fact has led to great difficulty in attempting to estimate the amount of it required by the body daily. Roughly speaking, there are about 10 milligrammes of the metal contained in an ordinary mixed diet (Stockman), and that quantity must therefore be regarded as sufficient to meet all physiological demands. 3 It is difficult to give precise figures as to the amount of iron present in different articles of diet. In animal foods it depends very much on whether the animal was bled or not, while in vegetable foods it varies very greatly with the amount of iron in the soil. Bunge 4 arranges some common foods in the order of their richness (not the richness of their ash) in iron as follows : Spinach, yolk of egg, beef, apples, lentils, strawberries, white beans, peas, potatoes, wheat. Boussingault 5 gives the following proportions of iron in 100 parts of the following foods examined in the fresh condition : 1 See Katz, Pfliiger's Archiv, 1896, lxiii. 1. 2 See Richet's ; dictionary of Physiology.' 3 A study of several typical American diets (United States Department of Agriculture, Office of Experiment Stations, Bulletin 185, 1907) shows that the majority yield from 11 to 19 milligrammes of iron per day. 4 Bunge, ' Der Kalk und Eisengehalt unserer Nahrung,' Zeit. f. Biolog., 1904 (N.F. 45), xxvii. 532. 6 Comptes Rendus, 1872, lxxiv. 1355. 19 — 2 292 FOOD AND DIETETICS PROPORTION OF IRON PER ioo PARTS OF FRESH SUBSTANCE. Blood of ox 003750 pig 0-06340 Beef . . . . . . . . . . . . 000480 Veal . . . . . . . . . . . . 000270 White fish 000150 Egg 000570 Wheaten bread . . . . . . . . 0-00480 Haricots . . . . . . . . . . 000740 Oats .. .. .. .. .. .. 0-01310 Lentils 000830 Potatoes . . . . . . . . . . 000160 Milk 0-00180 Carrots 0-00090 Maize 0-00360 Rice 000150 Apples .. . ■ ■■ .. • . O-0O20O Spinach . . . . . . . . . . 0-00450 Cabbage 0-003901 Burgundy .. .. .. .. .'. 001090 >in one litre. Beer . . . . . . . . . . . . 0^00400 J Stockman has pointed out 1 that these results are too high, probably from faulty methods of analysis. He gives the following amounts of iron in some common foods : 1 pint of milk .. .. .. .. 22 milligrammes iron. 100 grammes of oatmeal 3-1 ,, 300 „ fine bread .. .. 18 ,, 280 ,, common bread .. I'l „ 120 ,, beef-steak .. .. 47 „ From the results available, it may be concluded that beef and yolk of egg 2 are foods richest in iron, while milk and its derivatives, such as cheese, are amongst the poorest ; but even 5 pints of milk would supply the 10 milligrammes of metal required in the daily diet. Oatmeal and Egyptian lentils are amongst the richest in iron of vegetable foods, but bread, rice, potatoes and spinach also contain a good deal. As regards an ordinary mixed diet it may be said that the amount of iron which it contains is roughly proportional to its richness in proteid, for these two constituents tend to run parallel to each other. It should be noted that the iron contained in haemoglobin and its derivatives is very ill absorbed. 3 It is all the more necessary to point this out, as haemoglobin preparations are beginning to find a place in the treatment of anaemia. Amongst beverages, some mineral waters — e.g., Kronthal (green 1 Stockman (R. ),Journ. of Physiolog., 1895, xviii. 484, and 1897, X5£ i- 55 ! a l s0 Brit. Med. Journ., 1895, ii. 1473. For later analyses see ' Iron in Food ' (United States Department of Agriculture, Office of Experiment Stations, Bulletin 185, 1907). 2 See Katz, Archiv f. d. Gesam. Physiolog., 1896, lxiii. 1 ; also Hartung, Zeit. f. Biolog., 1902, xliii. 195. 8 V. Starck, Dent. Med. Wochensch., 1898, xxiv. 805. IRON 293 label) — contain a good deal of iron, and tea-leaves also are very rich in it, but probably little of the metal finds its way into the infusion. Wines are poor in iron, even the so-called ferruginous varieties having but a small proportion. That the habitual consumption of foods poor in iron may lead to anaemia is possible, though it is difficult to imagine a diet that would not contain the small amount of the metal required daily. Verdeil and Subbotin, however, have certainly found that the ash of the blood of dogs fed on meat contained much more iron than that of animals nourished on bread; and V. Hoesslein has shown that if young animals only receive as much iron as adults they become anaemic. On the other hand, once any marked deficiency of iron in the blood exists, it is almost impossible to make it good by merely dietetic means ; for no food is rich enough in iron salts to be able to accomplish the object in view. Hence, a knowledge of the amount of iron contained in different foods is, after all, of but little thera- peutic value. Sodium and Potassium. — Sodium is required in the body for the proper constitution of its fluids ; potassium for the construction of cells, and specially, perhaps, of the red blood cells and the muscles. Young animals deprived of potassium do not develop good muscles. As regards the amount of sodium and potassium contained in different foods, it may be said that the vegetable group is richest in the latter, and the animal group in the former. Bunge gives the following table of proportions : To I equivalent of sodium there is — In yolk of egg . . . . . . 1 equivalent of potassium. ,, milk .. .. .. .. 0-8 to 6 equivalents of potassium. ,, veal . . .. . . .. 4 ,, „ ,, wheat .. .. 12 ,, 23 ,, ,, ,, potatoes .. .. .. 31 ,,42 „ ,, .. peas 44 .. 5° „ „ It used to be believed that a deficiency of potash salts in the food was the main cause of scurvy. This belief, however, is now dis- credited, and it is probable that potash is useful, not so much for its own sake as for the vegetable acids with which it is combined, and which, by their oxidation, help to maintain a proper degree of alkalinity in the blood. 1 Green vegetables and fruits are a peculiarly valuable source of such salts. Sodium is chiefly taken in the form of sodium chloride, or common salt. Of this most people consume about 20 grammes daily, which is probably at least ten times as much as is really necessary to meet 1 See Wright ' On the Pathology and Therapeutics of Scurvy,' Army Medical Reports, 1895, xxxvii. 394. 2$4 FOOD AMD DIETETICS the needs of the body. There are not wanting people who maintain that this excessive consumption of salt is not only needless, but even harmful. 1 This, however, appears to be an extreme view. It may be admitted — for the experience of those who refuse to add any salt to their food amply proves it — that the amount of sodium chloride contained in a natural form in ordinary foods is quite sufficient for our needs ; but there is no proof that an extra addition of salt in the form of a condiment is in any way injurious to health. On the other hand, it is equally far from being proved that such addition conduces in any way to the well-being of the body. It has been asserted, for instance, that the addition of salt to the food aids digestion (Ogata), but more recent and exact experiments have shown that — in health, at least, and in moderate doses — salt has very little real influence on digestion at all, while in large quantities it actually delays the process. 2 If, moreover, sodium chloride is entirely removed from the food, the secretion of hydrochloric acid is lessened, or even arrested altogether, and upon this basis it has been urged that one should'slimit the use of salt in cases of hyperacidity of the stomach. Where, on the other hand, appetite is poor and digestive power feeble, the moderate use of salt in the food may act as a digestive stimulant in the same way as any other condiment. There is also reason to believe that it may slightly aid the absorption of food. 3 On the general processes of nutrition in the body, salt seems to be equally devoid of any pronounced effects. On the one hand it has been maintained that it acts as a cell stimulant, 4 while on the other it has been denied, on seemingly equally good grounds, that it has any distinct influence on metabolism at all. The latest and most conclusive experiments 5 tend to show that any action salt may have is in the direction of lessening nitrogenous waste, provided a sufficiency of water is supplied at the same time. From all the evidence, we may safely conclude that the artificial addition of salt to the food has either no appreciable influence on health at all, or, if it has any, it is an influence which must be described as favourable rather than otherwise. The craving for salt as an addition to the diet seems to be specially 1 See Mrs. Leigh Hunt Wallace's ' Salt in its Relation to Health and Disease.' 2 See Pawlow, ' Die Arbeit der Verdauungsdrusen,' and Schule, Zeit.f. Klin. Med., 1895, xxviii. 492, and 1896, xxix. 49. 3 Gabriel, Zeit.f. Biolog., 1892, xxix. 554. 4 Gamier and Lambert, Archives de Physiolog., 1898, xxx. 421. 5 Walther Straub, Zeit. /. Biolog., 1898, xxxvii. 527. For a recent review of the whole subject, see Belli, Zeit. f. Biolog., 1904 (N.F. 27), xlv. 182. COMMON SALT 295 strong amongst vegetable-feeders. An ingenious explanation of this fact has been advanced by Bunge on the lines that the large propor- tion of potassium in vegetable substances would tend to drive all sodium out of the body were the latter not constantly reinforced by the addition of salt to the food. This theory has been strongly criticised by Forster and others, and it is doubtful if it can be regarded as tenable — at least, in the extreme form in which it was brought forward by its distinguished author. Whatever the explana- tion, however, the fact remains that the artificial addition of salt is apparently more necessary in the case of people who live mainly on vegetable products than in those who consume a mixed diet. Phosphorus. — The importance of phosphorus as a building material in the body can scarcely be overrated. Wherever growth is most active there most phosphorus is found. It enters into the composi- tion of all cell nuclei, and it is abundantly present in the bones and in the central nervous system. One would naturally expect, there- fore, that wherever the building up of such tissues is going on rapidly a large supply of phosphorus will be required in the food, and it is not surprising to find that the development of young animals which are deprived of it is apt to be seriously impaired. Hence the great importance of a due supply of phosphorus in the food of growing children. The percentage of phosphoric acid (P 2 5 ) in some fresh foods is as follows i 1 Carrot Tnrnip Cabbage Potato Chestnuts Barleymeal Haricots Vegetable. . . 0036 per cent. 0058 0089 0140 0200 0230 0924 Animal. Pork . 0160 per cent Milk . 0220 „ Beef ■ 0285 Eggs ■ 0337 White cheese • °'374 Mutton . . • 0425 Gruyere cheese • 1350 The superiority of most animal foods in respect of this constituent is at once apparent. The phosphorus contained in foods is, for the most part, present in an organic form of combination, sometimes of a very complex sort, but in part also in an inorganic form as phosphates of the alkalis or earths. 1 Girard, Comptes Rendus, 1896, cxxii. 1387. 296 FOOD AND DIETETICS There is reason to believe that the organic forms are the more valuable for contributing to the growth and repair of tissue. 1 Examples of these are the chemical substances nuclein, lecithin, glycero-phosphoric acid, phospho-carnic acid and phytin, all of which are probably valuable dietetic sources of the element. The foods richest in these are such articles as yolk of egg, thymus, fish-roe, calves' brains, and the germ of wheat. Phytin 2 is particularly rich in organic phosphorus. It is an acid calcium magnesium salt of anhydrous oxymethylene diphosphoric acid contained in the seeds and tubera of plants. Being readily assimilated it is a valuable means of enriching the diet in phosphorus. It is doubtful, on the other hand, whether the inorganic com- pounds containing phosphorus are of much value in the body. They seem to be almost immediately excreted by the kidney or bowel, probably without exercising any important influence on metabolism. Cerebos salt consists of a mixture of 4 parts of calcium and magnesium phosphates with 96 parts of common salt. The phos- phates in such a preparation are present in a purely inorganic form, and are therefore of doubtful utility. In any case the recommenda- tion of such preparations is based upon the groundless assumption that an ordinary mixed diet is too poor in phosphorus to be able adequately to supply our need of that substance. It has been calculated that less than 2 grammes of phosphates are required to meet the daily needs of the body and that an average mixed diet contains from 3 to 5 grammes or more (Snyder). It may be remarked in this connection that we know of no diseased condition which can be clearly traced to a deficiency of phosphorus in the diet. This is true, indeed, not of phosphorus alone, but of all the other mineral ingredients of the diet with the exception of iron, and possibly also of calcium. A deficiency of iron in the food may, as already remarked, lead to the development of ansmia, and too little lime 1 Keller, however, in a review of the whole question (Zeit. j. Diat. uni Physik. Therapie, 1901, iv. 669), concludes that although phosphorus in organic com- bination is fully absorbed and assimilated, yet it has not been conclusively proved that it is more useful in this form than the inorganic phosphates, and still less that organic combinations of phosphorus are essential for life and growth. Hart, McCollum, and Fuller, also, found in experiments on pigs (Amer. Journ. of Physiol., igo8-og, xxiii. 246) that the administration of calcium phosphate could prevent the effects of a low phosphorus ration, and gave as good results in this respect as such an Organic phosphorus compound as phytin. On the other hand, Tunniclifie {Archiv. interned, de Pharmacodynamic et de Therapie, 1906, xvi. 207) found that the addition of calcium phosphate to the food of children did not increase the amount of phosphorus assimilated or retained, whereas the addition of an organic phosphorus compound did. * Supplied by the Society of Chemical Industry in Basle. PHOSPHATES 297 in the food may cause the bones of children to become soft; but with these rather doubtful exceptions it may be safely assumed that any ordinary diet will amply provide for all the mineral matter we require. If one should for any reason think it advisable to increase the proportion of phosphorus in the food, it would be wiser to have recourse to those articles already mentioned in which it is present in an organic form, rather than to pour into the body inorganic com- pounds which will probably be excreted from it just as they entered, That such organic forms are well absorbed there is now no doubt. 1 Oxalic acid, though not strictly speaking a mineral substance, may be conveniently considered here, for it is usually present in the diet in the form of oxalate of lime. Esbach gave the following table of the amount of oxalic acid in different articles of food : 2 Per 1,000. Black tea infused 5 minutes . . . . 2-060 Cocoa-powder .. .. .. .. 3 '520 to 4500 Pepper 3250 Coffee .. .. .. .. .. .. 0*127 Parsley . . . . . . . . . . 0006 Haricots . . 0312 Common beans .. .. .. .. 0158 Potatoes 0046 Good bread . . . . . . . . . . 0047 Crust .. .. .. .. .. .. 0130 Crumb .. .. .. .. .. 0*120 Buckwheat flour 0171 Barleymeal .. .. .. .. .. 0039 Maize flour . . . . . . . . . . 0033 Sorrel 2740103630 Spinach .. .. .. .. .. 1910103270 Rhubarb . . . . 2466 Brussels sprouts . . . . . . . . 0020 Cauliflower . . . . . . . . . . 0003 Beetroot .. .. 0390 French beans 0060 to 0-212 Salsifies . . . . . . . . . . 0*070 Tomatoes . . . . . . . . . . 0002 to 0*052 Carrots . . . . . . . . . . 0*027 Chicory 0*103 Dodder 0045 Endive 0*017 Lettuce . . . . . . . . . . 0-016 Dried figs . . . . 0270 Currants .. 0130 Prunes .. .. .. .. .. 0120 Gooseberries . . . . . . . . . . 0070 Plums . . . . . . . . . . . . 0070 Raspberries . . . . . . . . . . 0*062 Oranges . . . . . . . . . . 0030 Lemons . . . . . . . . . . 0030 Cherries . . . . 0025 Strawberries . . . . . . . . . . 0012 1 See Bergell, Fortschr. der Med., 1898, xvi. 1. 2 For other estimations see a paper by Apollina, ' Ueber die Oxalsaure im Organismus, ' Berlin. Klin. Wochenseh., 1901, xxxviii. 544. 298 FOOD AND DIETETICS It will be observed from the table that oxalic acid occurs in relatively large amounts in tea, coffee, spinach, rhubarb, sorrel, and pepper. Tomatoes are sometimes said to be rich in it, but this would appear to be an error. Their sour taste is due to the presence of citric acid. An animal diet diminishes the excretion of oxalic acid owing to the small amount of it which animal foods contain. 1 There would seem to be little doubt that the consumption of foods rich in oxalic acid may be a cause of the production of oxalic calculus. Dr. Prout, for example, states that he has seen well- marked instances in which an oxalate of lime nephritic attack has followed the free use of rhubarb (in the shape of tarts, etc.), particularly when the patient has been in the habit at the same time of drinking hard water. On the other hand, the condition of so- called oxaluria seems to have no relation to the amount of oxalates in the urine, but to be merely a variety of acid dyspepsia. Sulphur is present in the food almost entirely in a state of organic combination — chiefly in proteids. The amount of it present in different proteids varies considerably, as is shown by the following analyses of dry proteids. 2 There is in — Dried egg-white i-8o per cent. , , syntonin . . . . . . . . I 80 , , ,, albumin of wheat .. .. .. 1-55 ,, >• .. peas 0-40 „ „ gluten 070 „ We know nothinj of the advantages or otherwise of an increase or diminution of sulphur in the food. Chlorine is taken in almost entirely in the form of sodium chloride, or common salt. Except as a source of hydrochloric acid, nothing is known of its uses in the body, but the peculiar behaviour of the chlorides in some acute fevers would point to some special r61e attaching to them in metabolism. Iodine is present in small quantities in fish. 3 Thus, herring con- tain 2 milligrammes per kilo, mussels 1/9 milligrammes, salmon 1*4, ling and cod 1*2, and oysters 1/2. The only situation in the body in which this element has been detected is the thyroid gland, and the significance of its presence in the food is as yet quite obscure, though it may one day prove to be of some importance. Fluorine and silica are present in the body in small quantities, chiefly in the teeth and bones. Vegetable foods, and especially the cereals, are their most abundant source in the diet. 1 J. C. Dunlop, Journal of Pathology and Bacteriology, 1896, iii. 389. 2 'Richet's 'Dictionary of Physiology.' 8 See Lancet, 1899, ii. 1030 (abstract). ACIDITY AND ALKALINITY IN FOODS 299 The question of the acidity or alkalinity of foods may be con- veniently dealt with here. According to the reaction of their ash, foods may be divided into three groups i 1 (1) Acid foods, i.e., those which leave on incineration an acid-reacting ash ; (2) neutral food, with neutral ash ; and (3) alkaline foods, the ash of which is alkaline in reaction. Examples of these groups, arranged in the order of their acidity or alkalinity respectively, are as follows : A cid Foods. Neutral. Alkaline. Oats. Barley. Beef. Sugar. Vegetable oils. Animal fats. Carrot. Turnip. Potato. Wheat. Onion. Eggs. Rice. Milk. Blood. Maize. Peas. Lemon-juice. Orange-juice. Beans. Wright is of opinion that the exclusion from the diet of a sufficient quantity of ' alkaline ' foods leads to the development of scurvy and other diseases characterized by a diminution of blood coagulability. It is not improbable, also, that the proportion of acids or alkalies in foods may have important bearings on gout, but a discussion of the question would lead us into the sphere of too many controversial matters. 1 Wright, 'On the Pathology and Therapeutics of Scurvy, ' Army Medical Reports, 1893, xxxvii. 394. It must be pointed out that the reaction of the ash of foods still requires elucidation. I have not been able to find, for example, that meat leaves an acid-reacting ash. I 3°o J CHAPTER XVII WATER AND MINERAL WATERS About two-thirds of the total weight of the body is made up of water. The importance of water as a tissue-builder and its right to rank as a true ' food ' are at once apparent from this statement. About if\ pints of water are given off from the body every day in the various excreta and exhalations, and of this about one-sixth is actually formed in the tissues out of hydrogen and oxygen, the remainder being derived from the food and fluids consumed. If one reckons that half of the whole weight of solid food taken consists of water, then the amount required to be added to the diet in an actually fluid form would be approximately i\ pints (about two breakfast-cupfuls and three tumblerfuls). Obviously, however, the exact amount must vary very greatly with external conditions, and especially with the amount of sweat produced. The nature of the diet nas also an important influence on the amount of water consumed. On this point some interesting obser- vations have been made by Voit, examples of which are contained in the following table : Food consumed. Water consumed. Water in Faces. 800 grammes of bread . . .. .. 1,151 grammes. 212 grammes. 500 ,, of meat and 200 of fat . . 760 ,, 25 ,, 500 „ ,, 200 of starch 646 „ 16 „ 1,500 „ of meat 1,238 ,, 10 ,, It will be observed that, upon the whole, the amount of water consumed is proportionate to the amount contained in the faces. Where, as in a bread diet, the fasces are rich in water, an increased amount of fluid is consumed in order to make up for the loss from the bowel. This fact is entirely opposed to the statement not in- frequently made, that a diet mainly composed of vegetable ingredients tends to lessen thirst. On the other hand, if nitrogenous food, such as meat, is eaten in large quantities, the consumption of water must also be increased, owing to the necessity for providing for the proper elimination of urea and other products of nitrogenous waste. WATER IN THE DIET 301 For this reason the body tends to become richer in water if the diet is composed chiefly of fats and carbohydrates, and poorer in water if the food be rich in proteid. We have already seen that this excess of water in the body is one of the consequences of a purely vegetable diet. Effects of an Increase or Diminution of Water in the Diet. If a litre of water be swallowed on an empty stomach, almost the whole of it has been excreted in the urine within the space of three hours. This result is not due to mere dilution of the blood, for if normal salt solution be taken instead of water the result is precisely the same. 1 The real explanation would appear to be that the total volume of the circulating fluid in the body is a fairly fixed quantity, and is maintained by some regulating mechanism, so that it is not possible permanently to increase it. Nor can the volume of the blood be much reduced by diminishing the amount of water consumed. It is probable that such an effect can only be produced for a very short time. Recent experiments have shown 2 that if the water of the diet be reduced by about 27 per cent, there is indeed evidence that the blood becomes more concentrated, for in one such case the solids of the plasma rose from 8-8 to 11 -6 per cent., the number of red cor- puscles from 4,800,000 to 5,580,000 per cubic millimetre, and the specific gravity of the serum from 1027-4 to 1033-4. At the same time the arterial tension and the volume of the pulse were diminished. It was found, however, that equilibrium was very readily established, so that in a subsequent experiment the results were much less pro- nounced. This equilibrium seems to be brought about by an inter- change of fluid between the blood and the tissues. If the blood becomes more concentrated, water passes into it out of the tissues to make good the deficiency, so that the latter become drier. Hence it is that if the tissues become water- logged, as they do in cardiac dropsy, good results may be obtained by restricting the amount of fluid in the diet, for the tissues will then drain themselves into the bloodvessels. Conversely, if the blood be habitually overloaded with water, as it is apt to be, for example, in those who habitually consume large quantities of beer, some of the surplus passes out of the vascular area into the tissues, which then become abnormally 1 See Falck, Archiv f. Physiol. Heilhunde, 1852, xi. 125, and Schmaltz, Dent. Archiv f. Klin. Med., 1891, xlvii 145. s Dennig, Zeit. f. Didt. und Physik. Therapie, 1898, i. 281 and ii. 292. 302 FOOD AND DIETETICS watery. The tissues are therefore, in a sense, reservoirs of water, and it is to the rapid emptying or filling of these that sudden altera- tions in the weight of the body are usually to be ascribed. For example, in the experiment just mentioned, in which the fluids of the diet were reduced 27 per cent., the patient lost 8 per cent, of his weight within a week. It is important to bear this influence of water on the body weight in mind, for there is no doubt that the fluctuations which it brings about are often erroneously attributed to the loss or storage of solids such as fat. Much of the loss of weight in acute fevers, for instance, is certainly due to increased dryness of the body, and its very rapid restoration during convales- cence is the result of a retention of water in the tissues. The same holds good for obesity. Those who have insisted upon the aid which a restriction of the fluids of the diet furnishes in reducing a patient's weight have too often forgotten that the reduction is not necessarily due to the removal of fat at all. But we shall return to this subject in discussing the dietetic treatment of obesity. It has been stated that we are unable, by increasing or diminishing the amount of water in the diet, to bring about any permanent altera- tion in the volume of the blood. It must not be concluded from this that any regulation of the fluid consumed is entirely without effect in cases of disease affecting the cardio-vascular apparatus. Quite the contrary is the case. The mere temporary rise in the volume of blood to be driven round the circulation which the con- sumption of a large quantity of fluid brings about, and the increased labour which its excretion entails, may of themselves seriously hamper an already embarrassed heart ; and for this reason the amount of water in the diet, in cases of advanced cardiac disease and dropsy, may often be greatly reduced with nothing but benefit to the patient. 1 On the other hand, it must always be remembered that, if the consumption of fluid be reduced to the extent of increasing the viscosity of the blood, one increases thereby the resistance offered in the capillary circulation, and the increased strain thus thrown upon the heart may end by doing more harm than the restriction of the volume of the blood does good. One may perhaps best avoid both dangers by seeing that the amount of fluid consumed is not only moderate in quantity, but is evenly distributed over the day, so that there is no period at which the total volume of the blood is unduly swelled. It will be understood that very much the same remarks apply to 1 A reduction to 30 ounces or less per day can usually be managed without any difficulty. WATER AND DIGESTION 303 the treatment of aneurysm. What we have to avoid in that disease is throwing any undue strain upon the weakened vessel walls, and that can best be done by taking care that the circulation is never flooded by the sudden access of a large quantity of extraneous fluid. For a similar reason it is often advisable to restrict the consumption of fluids after severe haemorrhage, in spite of the great thirst of which the patient usually complains, for the vascular strain which any increase in volume of the circulating fluid must inevitably bring about may be quite sufficient to start the bleeding afresh. Influence of Water on Digestion. The first point which it is necessary to emphasize in this connec- tion is that water is not absorbed by the mucous membrane of the stomach at all. This is certainly a surprising fact, but it has been incon- testably established both by physiological experiment and by observations on patients suffering from obstruction at the outlet of the stomach. When water enters the stomach, it begins to flow out into the intestine almost at once, the process going on in little gushes through the pylorus until all the water has escaped. Roughly speaking, one may assume that a pint of water will have entirely escaped from the stomach in the space of about three-quarters of an hour. 1 The precise rate of leaving, however, is very markedly influenced by temperature. Hot water escapes from the stomach much more rapidly than cold. 8 The heat increases powerfully the movements of the stomach walls, and at the same time seems to cause the pylorus to open, so favouring the escape of the contents. The stimulating effects which hot water exerts on gastric peristalsis render it a powerful aid to sluggish digestion, while the ' unlocking ' of the pylorus which it brings about is probably the explanation of the almost instantaneous relief which it affords in many cases of ' cardialgia.' The fact that water is exclusively absorbed in the intestine has important bearings on the treatment of patients suffering from dilated stomach. In the extreme form of that disease, when the stomach contents are quite unable to escape through the pylorus, the entrance of water into the blood is arrested, and the patient is the victim of a ' tissue thirst,' to which much of the emaciation and discomfort from which he suffers must be attributed. Not only is this so. The deficiency in the supply of water to the blood may go 1 Moritz, Mimch. Med. Wochensch., 1894, xli. 816. 2 Schiile, Zeit. f. Klin. Med., 1895, xxviii. 461, and 1896, xxix. 49. 364 FOOD AMD DIETETICS so far that the proper excretion of waste products is interfered with, and toxic symptoms, such as coma or convulsions, may then supervene. In such cases there is an imperious necessity for getting water into the blood by some route other than the stomach, pre- ferably per rectum. The rapidity with which water passes through the stomach causes it to be a very dangerous vehicle of infection, for the hydrochloric acid of the gastric juice has no time to act upon any germs which it may contain. For this reason contaminated water is a more obnoxious carrier of disease that impure milk. All the greater, then, is the reason for insuring that our water-supply is above suspicion. It is commonly said that the free consumption of water at meals is apt to delay digestion by diluting the gastric juice. This state- ment is not well grounded. Water is itself a slight, though unimportant, excitant of gastric secretion, and experiment has shown 1 that even in quantities of \ litre (about a pint) it does not in any way affect the rapidity of digestion. Even i litre produces only slight slowing, while it requires quantities of ij litres (about 3 pints) to produce any marked effect. On the other hand, it must be remembered that water may actually hasten the digestion of some foods by softening them and favouring their reduction to a state of pulp, while hot water is, as we have seen, a powerful stimulant of the stomach movements. On the process of absorption, water does not seem to exercise any very marked effect, for even on a dry diet the solid constituents of the food entered the blood with their accustomed freedom (Dennig). Any influence which it may exert, however, is probably a favourable one. Influence of Water on Metabolism. The influence of water on the chemical processes of the body would seem to be very slight. It was formerly believed that an increased consumption of water was accompanied by an increased waste of the nitrogenous tissues. This is now regarded as an error. Any increased excretion of nitrogen which a free consumption of water entails is now ascribed, not to an increased breaking-down of the body substance, but to a washing-out of the tissues and the elimination of waste matters loitering in them. 2 This eliminative function of water is one of the first importance. It indicates the 1 Fleischer, Berliner Klin. Wochensch., 1882, xix. 97. * See R. O. Neumann, Archiv.f. Hygiene, 1899, xxxvi. 248, VARIETIES OF WATER 305 necessity for a free supply of that fluid in such diseases as gout, diabetes, and fevers, and in cases in which the excretory power of the kidney is deteriorated. Varieties of Water. A good drinking water should have little or no colour, no odour, a pleasant, fresh taste, and should contain only a moderate amount' of solid matter, 8f grains per gallon being a good average. A tumblerful of ordinary London water contains only about one grain of solids. A wholesome water should contain very little organic matter, and that .should be of vegetable origin, and if it has anything like a large proportion of chlorides it should be viewed with suspicion. The amount of lime salts which drinking water contains is a matter of some importance, and the relative merits of hard and soft water for drinking purposes have been much discussed. It has been maintained on the one hand that hard waters are apt to be productive in those who habitually consume them of such diseases as goitre and stone, while on the other hand it has been said that soft waters may favour the development of rickets. It must be admitted that neither of these contentions is very well founded, but it may be granted that it is well that the water one drinks should not contain more than 15 grains of lime salts in every gallon, and that the sulphate of lime is more likely to be harmful than the carbonate, for in some susceptible persons its presence may excite dyspepsia and diarrhoea. The fear that the use of soft water may lead to the development of rickets is quite groundless. When one remembers that even a hard water only contains about 0-002 grm. of lime in every 100 c.c, and that an infant requires about 0-32 grm. of lime daily, it will be evident that as a source of calcium for the bones water may be practically disregarded. On the other hand, there is no doubt that soft waters are more liable to become contaminated with lead than those which are richer in lime salts, and in that respect at least soft water may be a source of danger to health. The dangers of water as a source of infection, owing to its con- tamination with the germs of disease, have already been mentioned, and one of the reasons for it pointed out. The avoidance of such contamination, and the provision of pure water on a large scale, is one of the most important duties of the Public Health Authorities in any community, but the methods by which these results are to be obtained hardly fall within the scope of this work. One is 20 3 o6 FOOD AND DIETETICS frequently, however, asked for advice as to the domestic purification of water, and as to the best means of avoiding the risk of infection from it, especially during epidemics. The reply one should make to such inquiries is quite clear. The only sure method of render- ing water harmless is by boiling it. 1 It may be objected that this gives the water a flat and insipid taste, but that objection can easily be overcome by subsequent aeration in a gazogene, or by simply shaking up the water with air in a stoppered bottle. The invention known by the name of the Sparklets Process is also a very simple and efficient method of aerating water, and so over- coming the flatness produced by boiling.. For convenience in out- of-door use and when travelling it surpasses all other methods. The addition of toast, also, to boiled water communicates to the latter the flavour of some of the soluble ingredients of the toast, and has long been in use as a means of overcoming the flatness produced by boiling. Before leaving this subject, one must also warn the reader against the delusion so often cherished, that the addition of a little wine, or even spirits, to water can kill any germs that are in it, and so render it safe. That is not the case ; the proportion of alcohol in the mixture is never high enough to be certain of killing the organisms. Aerated and Mineral Waters. Artificial aerated waters, which are now so familiar, 2 were invented by the distinguished chemist Joseph Priestley in the latter half of .the eighteenth century. 3 They are made by charging water with carbonic acid gas at high pressure, the gas being derived from the action of vitriol on chalk. The best varieties in this country come from Belfast. Ordinary bottles of aerated water contain 3 or 4 volumes of carbonic acid gas to 1 volume of water ; syphons contain more. There is no doubt that this proportion is needlessly high, and has the effect of causing such violent ebullition when the bottle is opened that some of the contents are apt to be lost during the escape of the surplus gas. The only advantage attendant upon this process is 1 The Berkefeld and Pasteur filters, if used with intelligence and care, may also be depended upon to render water free from disease germs. 2 It has been calculated that upwards of 200,000,000 gallons of aerated waters are consumed in the United Kingdom per annum. 3 ' Directions for Impregnating Water with Fixed Air, in order to Communi- cate to it the Peculiar Spirit and Virtues of Pyrmont Water and other Mineral Waters of a Similar Nature,' Joseph Priestley, London, 1772. For a full account of the history of the subject see ' The Evolution of Natural Mineral Waters,' by William Kirkby (Manchester : Jewsbuiy and Brown, 1902). AERATED AND MINERAL WATERS 307 that the gas, as it passes off, withdraws from the water a consider- able amount of heat, so that aerated waters are always cooler to the taste than ordinary water kept under the same conditions. The varieties of artificial aerated waters which call for mention are as follows : 1. Ordinary Water impregnated with Carbonic Acid Gas. — The best makers obtain the water from artesian wells, so that it is of great purity. Ordinary water so impregnated is often, but erroneously, described as ' soda-water.' As soda is sometimes entirely absent, it is better to describe it simply as ' carbonated water.' 2. Aerated Distilled Water. — In this case the water is distilled prior to being charged with gas. It is therefore entirely free from mineral matter and from all impurities. Examples of such water are sold under the names of ' Puralis,' ' Salutaris,' and ' Globenaris.' 1 3. Water to which Various Chemical Salts have been added, e.g. : Soda water, containing 3 to 5 grains of bicarbonate of soda to the bottle. Medicinal soda water, containing 15 grains of bicarbonate of soda ditto. Potash water, containing 15 grains of bicarbonate of potash ditto. Magnesia water, containing 12 grains of carbonate of magnesia dittr, Carrara water, containing 5 grains of lime ditto. Lithia water, containing 3 to 5 grains of carbonate of lithia ditto. 4. Imitations of Various Natural Mineral Waters. — One of the best examples of these is seltzer- water, which is intended to be a sub- stitute for the natural water obtained from the Selters spring. Its ingredients are common salt, bicarbonate of soda, carbonate of mag- nesia, and hydrochloric acid. By the interaction of these constituents an aerated water is .produced which ' gives a good imitation of the peculiar mellowness of genuine seltzer.' An analysis of Schweppe's seltzer showed it to contain 1-13 grains of mineral matter per imperial pint, or 0-620 grain per bottle. A tumblerful had an acid-neutralizing power equal to that of 37^ c.c. of decinormal soda solution. 5. Sweetened and Flavoured Mineral Waters. — This is the large and popular group which includes lemonade, ginger-beer, et hoc genus omtie. The basis of their composition is water sweetened with cane- sugar, and rendered tart by the addition of an acid, then flavoured in any way desired, and finally charged with carbonic acid gas. A bottle of such water contains about 1 ounce of sugar (equal to five or six ordinary lumps). Unless the water is sold as a genuine ' fruit product ' the acid added is only exceptionally citric or tar- taric ; far more often one finds that a mineral acid is used, most 1 An excellent aerated distilled water is also prepared by Packham and Co. , Ltd. (Croydon). 20 — 2 308 FOOD AND DIETETICS commonly phosphoric, in the form of so-called ' phospho-lactic ' or * phospho-citric ' acid. Some makers employ acetic acid. If citric or tartaric acid is used, the amount added is about 10 grains per bottle, and, as a rule, the acidity of a bottle of ordinary mineral water of this class may be reckoned as about equal to that of a tablespoonful of good vinegar. The following recipes for making mineral waters are taken from the ' Mineral Water Maker's Manual ' (1896), and will serve to show the constituents of some of these products : Lemonade. Orangeade. Plain syrup, 1 1 gallon. Plain syrup, 1 gallon. Lemon tincture, 4 ounces. Orange tincture, 4 to 6 ounces. Acetic acid, 4 to 5 ounces. Acetic acid, 4 ounces. 1 to 1 \ ounces to the bottle. 1 to 1 \ ounces to the bottle. Ginger-beer. Gingerade. Plain syrup, 3 quarts. Plain syrup, 1 gallon. Boiling water, 1 quart. Tincture of ginger, 4 ounces. Oil of lemons, 24 minims. Acetic acid, 4 ounces. Acetic acid, 4 fluid ounces. Bitter orange tincture, q.s. Tincture of ginger, q.s. x to x j ounces to the bottle. 1 to ij ounces to the bottle. Ginger-ale. Plain syrup, 1 gallon. Compound tincture of ginger, 4 ounces. (Or tincture of capsicum, 1 ounce.) Acetic acid, 4 ounces. Sugar colouring, J ounce. 1 to ij ounces to the bottle. It will be observed that ' lemonade ' and ' orangeade ' have very little to do with the fruits from which they derive their names. The term ' ginger-beer ' or ' ginger-ale ' is even more ambiguous. The article so named may have nothing to do with ginger at all, for the requisite degree of sharpness is usually obtained by aid of tincture of capsicum. Genuine fermented ginger-beer (' stone ginger ') is a very different product. The following are its ingredients : Water . . . . . . . . 21 gallons. Sugar .. .. .. ..21 pounds. Bruised ginger . . , . i£ pounds Tartaric acid . . . . . . 6 ounces. Gum arabic . . . . . . 1 pound. Oil of lemon . . . . . . J ounce. Yeast . . . . . . . . I pint. As the result of fermentation it usually contains at least 2 per cent, of alcohol, sometimes considerably more. 1 10 pounds of sugar to 1 \ gallons of water. Natural mineral waters $w Natural Mineral Waters. These are obtained from natural springs, and the majority of them are impregnated with carbonic acid gas. The mineral matters which they contain are very various, but the most abundant are common salt and alkaline salts of soda or lime. For ordinary table use a water must not contain more than i per cent, of mineral matter, for above that one begins to get the specific effect of its salts. The following table contains a description of the natural table waters most largely used in this country, and the results which were obtained from a comparison of their respective acid-neutralizing powers : Water. Apollinaris 1 Rosbach Jobannis . Mineral Matter in an Imperial Pint (in Grms.). Kronthal (blue label) Kronthal (red label) Kronthal (green label) Perrier . 2 -27 1-05 i- 5 8 2-47 3-14 3 '04 Mineral Matter in a Bottle (in Grms.). I -40 - 6l 0"95 i-59 1-94 174 Acid-neutralizing Power of 250 c.c. (=1 tumblerful), expressed in c.c. of Decinormal Caustic Soda. 91'8 C.C. ^NaOH 29-3 C.C. 31*8 C.C. 1 1 5 c.c. 14-2 c c. 33 "5 c.c. 15 o c.c. General Description and Remarks. From spring in valley of Ahr (Rhenish Prussia). An alkaline, highly aerated, and slightly chlor- inated water. Chief constituents : sodium chloride and carbonates of soda, lime, and magnesia. From spring near Homburg. Mildly alkaline ; well aerated ; lightly mineralized ; containing about 12 grammes of sodium chloride and 05 grammes of earthy car- bonates in a litre. Produced at Johannis springs (Zoll- haus in Nassau). Mildly alkaline and well aerated. Chief salts are carbonates of lime, soda, and a small amount of sodium chloride. A lithiated Johannis is made from this, containing 1 grain of bicar- bonate of lithia per bottle. From Kronthal springs, in the Taunus district, Germany. A mildly alkaline and well-aerated table water, with 28 grammes sodium chloride, 08 gramme cal- cium carbonate, and 0*20 gramme of sodium carbonate per litre. Similar to the above, but contain- ing more mineral matter, and relatively more chloride and less carbonates. Apt to be mildly aperient. A chalybeate water, well aerated, mildly alkaline, containing a con- siderable amount of iron. A lightly mineralized and well- aerated natural water. The chief salt present is bicarbonate of soda. Obtained from springs at Les Bouillens, Vergeze, in France. 1 For a fuller description of this water see the Lancet (' Some Points concern- ing Natural Mineral waters in General and Apollinaris Water in Particular '), January 30, 1904, 3 io FOOD AND DIETETICS Less used are : Vichy (fitat), with 8 grammes solids per litre (5 grammes bicarbonate of sdda). It has a high acid-neutralizing power, 250 c c. =268 c.c. decinormal acid, but cannot be regarded as a water adapted for use in health. St. Galmier, which is largely used in France, has 2-8 grammes solids per litre, chiefly earthy bicarbonates. Contrexeville (Pavilion) has 2-3 grammes solids of a similar nature, and is only slightly gaseous. Sparkling Malvern is a pure natural water derived from the Malvern springs. It has i'8 grammes of solids per litre (o'866 gramme per bottle), including 1 gramme of sodium carbonate and 075 gramme of sodium chloride. Seltzer (Nieder-Selters, in Nassau) has 3-6 grammes solids per litre, consisting of 2'24 of sodium chloride and i'3 of carbonates. Adonis is a mildly alkaline water, containing 2-3 grammes sodium bicarbonate per litre. It is soft and well aerated, and is derived from springs situated in the Belgian Ardennes. Sinaro is a natural sparkling water derived from springs near Wiesbaden, Nassau. Its chief mineral ingredients are the bicarbonates of calcium and sodium. Uses of Mineral Waters. What dietetic advantages are obtained from the impregnation of water with carbonic acid gas ? Apart from the pleasant, sharp taste which such water possesses, one finds that carbonic acid gas is an undoubted aid to digestion. Indeed, it may be said that the mineral waters stand alone among beverages, in that they actually promote the chemical processes of digestion by causing an earlier and more abundant secretion of gastric juice. 1 Not only is this the case; carbonic acid acts as a stimulant to the movements' of the stomach, and so aids the mechanical processes of digestion also, while the bubbling up of the gas through the stomach contents doubtless facilitates their disintegration. There are cases, however, in which such waters should be avoided. Carbonic acid gas is rapidly absorbed from the stomach into the blood, and where that fluid already contains an excess of the gas, as it does in cyanosis, it may be well not to run the risk of adding to it. The mechanical distension of the stomach, too, which the escape of the gas induces, may be harmful in dilatation of that organ, and in other cases may hamper a weakened heart by causing the fundus of the stomach to press up against it. The use of mineral waters should also be avoided in cases in which the appetite is much depressed, for the carbonic acid gas, by lowering the sensibility of the stomach nerves, may still further impair the desire for food. Unfortunately, it cannot be justly claimed for the aerated waters that • they are always sterile. Carbonic acid gas is not fatal to 1 Penzoldt, 'Die Wirkung der Kohlensaure auf die Magenverdauung, ' Deut. Archiv. f. Klin. Med,, 1902, lxxiii. 200. USES OF MINERAL WATERS 311 organisms, with the exception, perhaps, of the cholera bacillus. On the other hand, the mineral waters supplied by the best makers are usually prepared from water obtained from artesian wells, and on that account are likely to be free from the germs of disease. The distilled aerated waters are also beyond reproach in this respect, but they should not be taken in large quantities unless along with food, for there is reason to believe that distilled water may have injurious local effects in the stomach, and lead to nausea and vomiting by destroying its surface epithelium. The question of natural versus artificial mineral waters must be decided entirely in favour of the former. For one thing, the natural waters do not contain any excess of gas, and a larger proportion of what they do contain is present in a combined form than is the case with the artificial waters. Hence their gas is given off more slowly, and they remain longer brisk, and are less apt to lead to sudden dis- tension of the stomach. The following experiment bears this out 1 : Natural Artificial Water. Water. Gas evolved . . 480 c.c. 760 c.c. ) Bottle opened and exposed Gas remaining . . 1,010 c.c. 723 c.c. j for half an hour. Total .. 1,490 c.c. 1,4830.0. There is also reason to believe that the effects of the salts in natural mineral waters are such as cannot be obtained from any artificial imitation of them. The reasons for this have been discussed by Koeppe. 2 He attributes it to the fact that the natural waters contain traces of many salts which are not present at all in the artificial waters, and which are yet not without effect on the body. Being formed under pressure, too, the natural waters contain double salts, the physical effects of which are not comparable to each salt taken separately, for each salt has its own partial pressure, while for any given degree of concentration one finds fewer dissociated ' ions.' This is not without influence on the physical processes of osmosis, and as a matter of fact it has been found that more mineral matter is absorbed in a given time by the intestine of a dog from a natural than from an artificial water. The slight alkalinity of some of these waters renders them useful additions to the more acid wines, for the inhibitory action of the latter on the saliva is thereby corrected. The sweetened mineral waters, such as lemonade, are apt to dis- 1 Analytical Reports, Lancet, August 8, 1891. 1 See footnote, p. 285, and Dr. Brasch, Zeit. f. Diat. und Physih. Therapie, 1900, iij. 688, 3" FOOD AND DIETETICS agree with the stomach and produce ' acidity,' both by reason of the acid which they contain, and also from the action of their sugar on the secretory processes in the stomach, and perhaps also by fermenta- tion. On the other hand, it must be remembered that such beverages are by no means devoid of nutritive value, for a bottle of one of them contains enough sugar to yield nearly 115 Calories of energy to the body ; and their refreshing influence in fatigue may also be explained by reference to the value of sugar as a food in exhaustion (see p. 282). L 3i3 J CHAPTER XVIII TEA, COFFEE, AND COCOA In dealing with these beverages, it will be convenient to take up the history, mode of manufacture, and chemistry of each of them separately, and then to consider their action on digestion and their uses in the diet together. Tea.i 1 . History. — Tea was introduced into Europe by the Dutch East India Company in the year 1610. As its price was at first ten guineas a pound, it can be readily imagined that it grew but slowly in popularity, and even in 1660 we find Pepys writing in his Diary : ' I sent for a cup of tee, a China drink, of which I had never drank before.' By the beginning of the last century the annual consump- tion had risen to 1 J pounds per head of the population, and now, 100 years later, it amounts to fully 6 pounds per head. In Great Britain, indeed, we consume more than all the European countries put together, about 600,000 pounds of tea, or 4,000,000 gallons of the beverage, being used daily. It is only in Australia, where tea is so largely used in the Bush, that the consumption surpasses that of this country, amounting as it does to 9 pounds per head of the popula- tion annually. Up to the year 1862 nearly all our tea was obtained from China, the imports from that country reaching their maximum in 1879. Since that time the consumption of China teas has rapidly declined, their place being taken by Indian tea, and, since 1 880, by teas -grown in Ceylon. The proportion of China tea is now less than 12 per cent, of the total import. 2. Mode of Manufacture. — Tea was originally obtained from the 1 I am indebted for much valuable information on the subject of tea to the following, among other publications : Bannister's Cantor Lectures, 1895 '• A.. G. Stantor, journal 0/ the Society 0/ Arts, January 25, 1890 ; Prescott, Popular Science Monthly, xx. 359, 1882. 3*4 FOOD AND DIETETICS leaves of the Thea chincnsis and Thea assamica, both of the Camellia order ; but many hybrids are now used for tea production. The plant ' flushes,' or sends out young shoots, four times in the year, and is ' picked ' at each ' flush.' In China and Japan the best tea is obtained from the first ' flushing,' but in India and Ceylon this is not the case. The varieties of iea are named according to the different leaves from, which they are produced (Fig. 28). The young shoot has two small leaves at its tip which contain least fibre and most juice, and therefore produce the finest sort of tea. In India and Ceylon, tea produced from these leaves is called ' flowery ' and ' orange ' ' Pekoe,' or, if the leaves are still smaller, 'broken Pekoe.' The tea produced from a somewhat larger leaf just below this is called ' Pekoe '; the next largest leaves produce 'Souchong'; the leaves below that, ' Congou ' (though these are not often picked now) ; while a still coarser leaf near the base of the shoot used to yield ' Bohea,' which has now, how- ever, almost disappeared from commerce. 1 In China a slightly different nomenclature is used, the whole end of the young shoot, with its cluster of leaves, going to form ' Pekoe,' while the leaves below that are used for the production of ' Souchong.' It should be noted also that the term ' Congou ' is often, applied in the retail trade to blends, while ' Pekoes ' and ' Souchongs ' are unblended teas. The treatment of the leaves after they are picked varies according as black or green tea is to be produced. For the production of black tea, the leaves are ' withered,' then rolled till they become soft and ' mashy,' the object of this being 1 ■ Pekoe ' is derived from ' poco,' the hair or down on the young buds ; ' Souchong ' means ' little sprouts '; and ' Congou ' signifies labour, from the care required in the subsequent treatment of the leaves. Fig z8. — Young Shoot of Tea Plant (after Money). a. Flowery Pekoe ; b. Orange Pekoe ; c, Pekoe ; d, Souchong (first) ; e, Sou- chong (second) ; /, Congou ; H, Bohea ; a and b (mixed), Pekoe ; a, b,e, d, and e, Pekoe-Souchong. VARIETIES OF TEA 315 to break up the fibre and cells of the leaf, and liberate the con- stituents, so that they are afterwards more easily extracted, and then allowed to ferment. During the process of fermentation, some of the tannic acid in the leaves appears to be oxidized and converted into less soluble forms, while more essential oils seem to be pro- duced, and a certain amount of bitterness developed. After fermentation is complete the leaves are ' fired ' in a drying- machine. For the production of green tea, the fresh leaves are withered in hot pans at a temperature of 160° F. (Chinese method), or steamed (Japanese method) ; then rolled to break them up and liberate their juices ; then ' fired.' It will be observed that the chief difference between black and green tea is that the former is fermented, while the latter is not ; and one of the main results of fermentation seems to be to render the tannic acid less soluble, so that, as we shall shortly see, an infusion of green tea contains more tannin than an infusion of black. In former days a good deal of so-called green tea was really made in the same way as black, and subsequently ' faced ' with Prussian blue or indigo to give it the proper colour ; but I am informed that this does not take place now to any important extent. We have seen that the quality of teas varies with the age of the leaf from which they are prepared, the younger leaves yielding the finest tea. Apart from this cause of variation, teas show marked differences according to the country and district in which they are produced. Chinese teas have the most delicate flavour of any, but are rather lacking in ' body '; they are also devoid of any marked astringency. Indian teas, and especially those produced in Assam, have the greatest degree of ' body ' and astringency. This makes them powerful teas, suited rather for blending with milder varieties than for drinking alone. Ceylon teas have plenty of body, and a rich and peculiar flavour, but have not so much strength or pungency as the Indian varieties. According to the district in which they are produced, Chinese black teas may be divided into : 1. Monings, from North China, with a small and delicate leaf and a peculiar malty flavour. 2. Kaisows, from South China, the so-called red-leaf teas, because the original teas grown in this district had a reddish leaf. 3i6 FOOD AND DIETETICS 3. Oolongs, from Formosa, pungent and slightly bitter, yielding a pale infusion, and chiefly used for purposes of blending. 4. Scented orange Pekoe and scented Caper came from the Canton district, and yield a pale, strong infusion with an aromatic flavour, for which reason they are used to give bouquet to blends. Caper is really an unfermented tea, highly fired, and standing intermediate between the black and green varieties. Of Indian black teas those from the Darjeeling district are best, being less rough and astringent than those from Assam, and well adapted for drinking alone. It should be remembered that most black teas in the market are really blends of Indian, Ceylon and China in different proportions. Most green teas come from North China and Japan, the latter yielding the best. Very little is produced in India. The chief varieties of green tea are Young Hyson 1 and Gunpowder, the former corresponding to a Souchong among black teas, and the latter to Congou. In judging a tea, professional tea-tasters are guided by the nature of the liquor and the characters of the infused leaves or ' out-turn.' The infusion should be of a reddish-golden colour, pungent in flavour, but not too bitter or astringent, and not ' thin ' or ' hard.' The infused leaves should be of a bright coppery tint, and evenly extracted, so that some do not look darker than others ; they should be uniform in size, and after five minutes' infusion should not be completely unrolled. There should not be too much stalk mixed with the leaves. 3. Chemical Composition, of Tea. — The following analyses of two typical varieties of tea are given by Bannister : 2 Congou, at Young Hyson, 2S. ioii. at 3s. (Typical (a Typical Black Tea). Green Tea). Water 8-20 5-96 Caffeine 324 2-33 Albumin (insoluble) .. .. 1720 1683 ,, (soluble).. .. .. 070 080 Alcoholic extract . . . . . . 679 7 05 Dextrin . . . . . . . . — 050 Pectin and pectic acid .. ..260 322 Tannic acid 1640 2714 Chlorophyll and resin . . . . 460 420 Cellulose 34° 2590 Ash .. 627 607 1 Young Hyson =Yu-Chien, 'before the rains.' s Cantor Lectures, 1890. Caffeine. 3-85 per cent 4°3 »» 402 11 402 11 375 11 3Hi 11 374 289 308 19 71 11 COMPOSITION OF TEA 317 Of these ingredients, the most important are the alkaloid caffeine (also called theine) and tannic acid ; for these, along with a small proportion of volatile oil (J per cent.), are the ingredients to which the chief effects of tea on the body are due. The importance of the caffeine and tannic acid is so great that it may be well to bring forward some further and very exact estimations of these ingredients in different teas which were made by Allen i 1 Description of Tea. Tannic Acid. Ceylon, whole leaf (Pekoe) .. .. 1301 per cent. „ broken leaf .. .. .. 1231 Assam, whole leaf (Pekoe) . . . . 1008 ,, broken leaf .. .. .. 1133 Java Pekoe .. .. .. .. 1293 Kaisow, red leaf . . .. .. .. 11 35 Moning, black leaf .. .. .. 11 76 Moyune Gunpowder .. .. .. 1295 Natal Pekoe Souchong . . . . . . ggo Indian and Ceylon teas are richer in all the chief ingredients (caffeine, tannic acid, and volatile oil) than China teas. Green tea is richer in tannic acid than black, but the amount of caffeine in the two is almost the same. The following table 2 (from analyses by Mr. Y. Kozai in Japan) shows the difference in composition between green and black tea produced from the same leaves : Original Leaves. 3 Per cent. Crude proteid .. .. .. .. 3735 ,, fibre .. .. .. .. io - 44 Ethereal extract . . . . . . 6'4g Other nitrogen-free extract .. .. 2786 Ash . . . . . . . . . . 497 Caffeine .. .. .. .. .. 330 Tannic acid 4 .. .. .. .. 1291 Soluble in hot water . . . . . . 5097 Total nitrogen .. .. .. .. 5-97 Albuminoid nitrogen .. .. .. 4-11 Caffeine , , . . . . . . 096 Amido ,, .. .. .. o'gi The table shows quite clearly the reduction in tannic acid whicb the process of fermentation brings about in black tea. Scott Tebb 5 compared the amounts of tannic acid and alkaloid extracted from different forms of tea (8 grammes of the tea being infused with 600 c.c. of boiling distilled water for five minutes) with the following results : 1 'Commercial Organic Analysis,' vol. iii., part ii. 2 See United States Department of Agriculture, Division of Chemistry, Bulletin 13, 1892. 3 Dried at 105 C. 4 As gallo-tannic acid. 5 ' Tea and the Effects of Tea Drinking ' (London : T. Cornell and Sons, 63, Borough Road, S.E.). Green Black Tea. Tea. Per cent. Per cent 37'43 3890 1006 1007 5-52 582 3143 3539 492 4'93 320 3 3° 1064 489 5374 4723 5 99 622 3 94 411 093 096 113 116 3*8 FOOD AND DIETETICS Class of Teas. Number of Analyses. Per Cent. Extract. Per Cent. Alkaloid. Per Cent. Tannin. Ceylon China 18 12 13 26ll 26'04 2212 ^•84 2-68 2 '40 7'43 7-85 6-o8 An analysis of the teas most widely consumed in London Restaurants gave the following results : RESTAURANT TEAS. (Infusion of 8 grammes with 600 c.c. of boiling distilled water for five minutes.) Proportion of Tannin No. Description and Retail Price Per Cent. Per Cent. Per Cent. Correspond- District. Per lb. Extract. Alkaloid. Tannin. ing to 2'S per cent. Alkaloid. 1 " China" Tea 2S. 2d. 20'20 2-51 4-85 5HI 2 Ordinary Black Tea 2S. 2d. 25-60 2-04 9 - °3 1239 3 ' ' China ' ' Tea 2S. od. 20-06 215 3 02 3 93 4 Ordinary Black Tea 2S. od. 27'go 2-69 974 10-13 .5 " Russian" Tea 2S. 6d. 23"5° 2-30 5-36 6-52 6 Ordinary Black Tea 2S. 8d. 24 60 3-02 603 5 '59 7 "China" Tea 2S. id. 24-50 222 5-85 7 '37 8 Ordinary Black Tea 2S. 2d. 28-31 2-72 8-44 8-69 The composition of the infusion is of much greater practical importance than that of the leaves from which it is made. If tea be infused for five minutes in the usual way, about 25 per cent, of the weight of the leaf goes into solution. In making an ordinary teacupful of tea (about 150 c.c), 5 grammes (about jounce) of dried leaf are usually employed, and a cupful of such tea contains in solution about 15 grains of solid matter. The bulk of this is made up of gummy matters, extractives, etc., but the most important ingredients are the caffeine, and tannic acid. The caffeine is so soluble that it is practically all dissolved out of the leaf immediately infusion has begun. With tannic acid this is not the case. There is certainly less tannic acid after three minutes' infusion than after five, and less after five than after ten ; but beyond that one does not find much increase, for by that time practically the whole of the soluble matters have been extracted from the leaf. The following experiments bear upon this point : AMOUNT OF TANNIC ACID IN TEA 319 Hughes 1 found the following proportions of tannic acid extracted in different times : Five Minutes' Thirty Minutes' Infusion. Infusion. Assam 1035 per cent. 1476 per cent. Ceylon 860 „ 10S8 „ China 780 ,, 940 ,, Hale White 2 found : Three Minutes' Infusion. Finest Assam .. .. 11-30 per cent. ,, China .. .. 777 „ Common Congou .. 937 „ (The figures represent percentage of tannic acid in weight of leaf used.) The following results were got by Dittman : Caffeine. Per cent 258 279 315 Fifteen Minutes' Infusion. 1773 per cent. 7'97 1115 3 29 363 373 Tannic Acid. Per cent. 3"o6 378 587 73° 677 809 China tea (8 samples) { J minutes ' infusion Ceylon ,. (6 „ ) j ^ Indian ., (12 ,, ) < ^ • > \ ■. ; ^ IO It will be observed that the proportion of tannic acid is much more affected by the length of infusion than that of caffeine. Finally, one may quote the experiments of Green, 3 in which 420 c.c. of boiling distilled water were poured on 3^ grammes of tea, and infusion carried on under a cosy for from five to forty minutes, with the following results as regards the composition of the beverage : Five Ten Twenty Forty Minutes' Minutes' Minutes' Minutes' Infusion. Infusion. Infusion. Infusion. Per cent. Per cent. Per cent. Per cent. 25 3 268 281 Caffeine 11 i'3 116 Tannic acid .. 68 85 . 117 163 Nitrogen in 116 in 1 04 Ash •• 352 409 415 448 All these experiments agree in showing that the longer tea is infused the higher is the proportion of tannic acid dissolved out, while the proportion of caffeine, on the other hand, is but little affected. From this, the practical inference is that, if one wishes to avoid having much tannin in tea, one should infuse it for as short a time as possible. The writer has made a number of experiments with the view of determining the amount of caffeine and tannic acid present in an 1 Journal of Society of Arts, January 25, 1895. 2 Brit. Med. Journ., 1889, i. 91. 3 Thorpe's ' Dictionary of Chemistry.' &o FOOD AND DIETETICS ordinary teacupful of tea infused in the usual way. The results are contained in the following tables : CAFFEINE IN TEAS. 1 Caffeine in Grains Tea. Grammes per per 150 c.c. Teacup. Ceylon Pekoe 00787 121 Fine Darjeeling 00751 105 Common Congou .. .. .. 00745 114 Moyune Gunpowder (green) . . 00645 099 Imperial Gunpowder . . . . 00590 090 Household blend 00580 089 Young Hyson 0-0547 084 Fine Moning 00510 078 Fine Assam 00475 073 TANNIN IN TEAS. 2 Tannin as Gallo- Grains Tea. tannic Acid per per 150 c.c. 'of Infusion. Teacup. Moyune Gunpowder . . . . 0273 420 Young Hyson .. .. .. 0242 372 Imperial Gunpowder . . . . 0227 349 Ordinary black blend .. .. 0-173 266 Fine Darjeeling 0168 258 Good black blend 0-168 2-58 Ceylon Pekoe 0142 218 Lapseng Souchong . . .. 0087 133 Fine Assam.. .. . . .. 0080 123 Fine Moning 0058 089 As a rule, one may say that a teacupful of tea of ordinary strength infused for five minutes contains about 1 grain of caffeine, and twice or three times as much tannic acid. It may be well to give some practical rules for the proper method of making tea based on the facts as to its chemistry which we have just been considering. This is all the more important as it is comparatively rare to get a really good cup of tea, in spite of the popularity of the beverage. It must be admitted, too, that the fault lies oftener with the method of infusion than with the quality of the original leaf employed. And, firstly, the tea should really be infused, not boiled or stewed, as is so often the case. The character of the water is of the first importance. The Chinese rule is, ' Take the water from a running stream ; that from hill springs is best, river water is the next, and well water is the worst.' The meaning of this is that the water should be well aerated. Prolonged boiling makes it flat by driving 1 Eight grammes of dry leaf were infused with 300 c.c. boiling water for five minutes. The caffeine was estimated by Allen's method. 2 Eight grammes of the dry leaf were infused for five minutes in 300 c.c. of water, and the tannin estimated by Procter's modification of Lowenthal's process. HOW TO MAKE TEA 321 off the dissolved air. Hence, the water should have just freshly come to the boil. If it is already flat, it is a good plan to pour it into a jug from a height, for this causes it to take up some air again. 1 The water should not be too hard, for the presence of lime salts seems to interfere with the extraction of some of the constituents of the leaf. If only hard water is obtainable, it is a good plan to add a pinch of soda to the teapot. Water which is too soft is also bad, for it seems to extract a bitter principle from the leaf. Moderately soft water, therefore, is the ideal to be aimed at. The quantity of leaf infused demands some attention. The domestic rule of ' a teaspoonful for each person and one for the pot ' is an uncertain one, for the weight of a spoonful of tea is a very variable 2 quantity, depending as it does very much on the tightness with which the leaf is rolled. Tea-tasters use the weight of a new sixpence (43^ grains) to 3! ounces of water, and this, which is a somewhat smaller propor- tion of tea than that given by the domestic rule, yields a more satisfactory though weaker infusion. It must be remembered, how- ever, that the popular taste is for a strong beverage with a good deal of ' body.' 3 The water, as we have seen, should be first brought to the boil, and the teapot should be thoroughly heated, so that the temperature may be maintained : for it is only at the boiling-point that some of the volatile constituents of the leaf, to which the beverage owes its aroma, can be properly extracted. Infusion should be of limited duration — not more than four or five minutes, for prolonged treatment extracts too much tannic acid, and withdraws from the leaf also bitter substances which are better left behind. In addition to this, prolonged infusion dissipates the volatile oil to which much of the fragrance of a good cup of tea is due. The use of a ' cosy ' during infusion does no harm, but whenever the process is completed the liquor should be poured off into another hot teapot, which may then be kept covered if desired. The addition of milk or cream, though an outrage in the eyes of 1 The Chinese directions for preparing the water are as follows : ' The fire must be lively and clear, but the water must not be boiled too hastily. At first it begins to sparkle like crabs' eyes, then somewhat like fishes' eyes, and lastly it boils up like pearls innumerable, springing and waving about.' 2 The weight of a caddy spoonful varies from 39 to 87 grains (Smith). s For the economical preparation of good tea the thorough crushing of the leaf is of great importance, so that its ingredients may readily be extracted. The powdered tea of Japan is ideal in this respect, and in this country the ' tea tabloids ' recently introduced are deserving of a word of praise for the same reason. 21 322 FOOD AND DIETETICS connoisseurs, is to be commended on hygienic grounds, for the albuminous matter of the milk tends to throw down some of the tannic acid of the tea in an insoluble form. Sugar does not in any way increase — indeed, it may detract from — the healthfulness of the beverage, but adds considerably to its nutritive value. All second brews should be avoided, for a single infusion is sufficient to remove from the leaves all the useful constituents of the beverage. Coffee. Coffee was introduced into this country in the year 1652 by a certain Mr. Daniel Edwards, a retired Smyrna merchant, who set up his Greek servant in a coffee-house, the first of its kind in London, in St. Michael's Alley, Cornhill. As a beverage it has never attained the popularity with us that it has won on the Continent, for at the present day we consume less than a pound of it per head of the population annually, whereas in Holland the con- sumption amounts to 21 pounds. This may be explained partly, perhaps, by the fact that we do not know how to make coffee, but mainly by its great expense when compared with its principal rival, tea. Coffee is derived from the Caffaa arabica, originally produced, as the name implies, in Arabia, but now cultivated in many tropical countries. The plant produces three harvests annually, the fruit resembling a cherry, in which the 'coffee-bean' corresponds to the stone. The bean consists of two halves placed face to face and enclosed in a husk. The pulp is softened by fermentation and removed, and the beans, still enclosed in their husk, are dried in the air. The husk is separated by rolling, and the beans are then separated from the delicate parchment-like skin which covers them, and assorted according to size. Several varieties of bean are found on the market, the chief being as follows i 1 1. Mocha. — The genuine beans of this, the finest sort of coffee, are derived from Arabia Felix, but much so-called Mocha coffee is really produced elsewhere, chiefly, perhaps, in Guatemala. Two varieties are met with, ' long berry ' and ' short berry.' The former are grayish -yellow in colour, and give a rich, mellow liquor. The latter are pale greenish -yellow, and give a clearer and more delicate infusion (Bannister). 2. Mysore. — Here again the name is apt to mislead, for the majority 1 Bannister's Cantor Lectures, 1890. VARIETIES OF COFFEE 3 2 3 of coffees of this name come from Java and Ceylon. The berry is bluish-gray in colour and yields a pure, strong and clear liquor. 3. Ceylon Plantation. — The berry is of a pale greenish tint, and yields a clear beverage of full but smooth flavour and fair body. This coffee is largely used for blending. 4. Costa Rica. — A bluish-gray berry yielding a strong but rather coarse liquor. 5. Java. — A very fine coffee, with large, pale, oblong berries yielding a strong, clear liquor. 6. Brazil. — A coffee of peculiar flavour, used chiefly for mixing with other varieties. In order to prepare the beverage, the berries must first be roasted. The composition of raw and. roasted coffee is thus contrasted by Bannister : Caffeine Saccharine matter Caffeic acids Alcoholic extract (nitrogenous and colouring matters) Fat and oil Legumin Dextrin Cellulose and insoluble colour- ing matter Ash Moisture . . Mocha. East I Raw. Roasted. Raw. I 08 082 I'll 955 846 043 474 890 958 6 90 1260 987 087 14-14 13 59 1 1 -23 1 -24 431 II-8I 11-23 084 37'95 374 898 4862 456 063 386 398 964 Roasted. I°5 041 452 1267 13 41 I3-I3 1-38 4742 488 113 The chief physical change which results from roasting is that the berries are rendered brittle and can now be ground. Chemically, one finds that they lose from 13 to 20 per cent, of their weight, the loss consisting in nearly equal parts of moisture and organic matter. The lost organic matter includes about 21 per cent, of the total caffeine and 10 per cent, of the fat. 1 If the coffee is ' over-roasted,' the loss of caffeine may be considerably greater. The most important substance produced in the coffee by roasting is an oil, caffeol, to which the aroma of roasted coffee is due, and the fragrance of which is so powerful that one drop is said to be sufficient to scent a whole room. 1 Analyst, p. 287, 1897. 21- 324 FOOD AND DIETETICS Composition of the Infusion. From 25 to 35 per cent, of the coffee used in making the infusion goes into solution. This percentage of solubility is about the same as that of tea, but seeing that a much larger quantity of coffee is taken than of tea, the amount of solids per cup is considerably higher in the former than in the latter beverage. If 2 ounces be used to make a pint, a teacupful of the beverage will contain in solution about 4-2 grammes of solids, of which 0*65 is mineral matter. This is supposing the coffee to be filtered. As ordinarily drunk, some suspended matter must also be included. An analysis which I have made of coffee of the above strength, showed the. presence of 1-7 grains of caffeine per teacupful, and 3-24 grains of tannic acid. 1 According to this resul: , a cup of black coffee contains very -much the same amount of caffeine and tannic acid as an equal quantity of tea. A breakfast-cupful of cafe au lait is com- posed of about 1 part of black coffee to 3 of milk, and will not, therefore, contain more of the alkaloid than a teacupful of tea. French coffee demands a special word of mention. It usually contains more or less chicory, and sometimes also some burnt sugar. Chicory is the root of the wild endive, kiln-dried and broken into fragments. The process of drying converts its sugar, of which it may have 10 to 18 per cent., into caramel. There is no reason to believe that chicory is in any way injurious to health, but 1 pound of it is equal in colouring power to 2-8 pounds of coffee, and as a pound of chicory costs 3^d., while a pound of coffee costs about is. 5d., it is evident that 3^d. worth of the former is equal, as far as the mere appearance of the beverage goes, to 3s. nd. worth of the latter. Hence the great temptation to adulterate coffee with chicory, a process which has done much to discourage the consumption of coffee in this country. As a rule, French coffee contains about one- third of its weight of chicory, but sometimes the proportion may be as high as 80 per cent., or even more. Coffee-making. The. secret of having good coffee is to make it strong and to make it hot. We mostly fail in this country by not using enough. Two ounces to the pint is the smallest proportion which will give a good result. It is important that the coffee should be freshly roasted, for its fragrance is quickly dissipated on keeping, and in roasting one must see that the beans are of the same size ; otherwise they will be unequally fired. For this reason mixing should be carried out after 1 Reckoned as gallo-tannic. COCOA 323 toasting, and not before. Care also must be taken that the grinder is quite clean, for if any stale coffee is left in it the whole may be spoilt. The water should be just boiling, and infusion may be carried out either in a jug or in a porcelain percolator. For break- fast coffee a mixture of coffees — e.g., half and half Mocha and Planta- tion—may be used, and the addition of a little ground chicory is liked by some, but for black coffee the latter should always be omitted. Three parts of milk to one of coffee is about the proper proportion for cafe an lait. Cocoa. Cocoa was first brought to Europe from Mexico by Columbus in the year 1520. It was known at that time as ' cacao,' but the name . got changed with the lapse of time. Although introduced consider- ably earlier than either tea or coffee, it is only of late years that it has attained any wide popularity, and that chiefly through the energy and enterprise of some of its manufacturers. The cocoa-plant is the Theobroma cacao, the fruit of which resembles a vegetable marrow or cucumber. Embedded in the pulp of the fruit are many seeds, each about the size of a haricot bean, and it is from these that cocoa is prepared. The seeds are separated from the pulp, and placed in heaps for several days to ferment, or ' sweat.' This causes any adherent pulp to become loose, and at the same time modifies the bitterness of the seeds and produces in them a dark colour. They are then roasted, which renders them brittle and loosens the husk, so that the two halves of the seed come out separately on pressure in a machine as cocoa-nibs. The nibs are either sold as such or are ground between hot rollers, which, by melting the fat that they contain, reduces them to a fluid condition. Most of the fat is removed by pressure, and the remainder of the cocoa is then run into moulds, from which it is removed as slabs. For conversion into ' soluble cocoa ' or ' cocoa essence ' the slabs are again ground down to an impalpable powder. Various names are applied to different preparations of cocoa. The method of preparing soluble cocoa has just been described; but it should be noted that the term is really a misnomer, for, strictly speaking, there is no such thing as a soluble form of cocoa. All that the term implies is that the powder is so finely divided that it easily remains in a state of suspension when mixed with water. In order to aid the suspension, various methods of treating the cocoa are sometimes adopted. The addition of alkali is a favourite device, especially with Dutch manufacturers. It aids suspension by saponifying and emulsifying the fat, and at the same time softens the 326 FOOD AND DIETETICS fibre of the cocoa, so that it can form a sort of pulp with water. It also has the effect of deepening the colour of the beverage, and so of making it look stronger. The free addition of alkali is objected to by some as being injurious to health, but it is very doubtful if that can be fairly alleged against it. There are also methods of increasing the solubility of cocoa by the aid of heat, and to these no objection can be urged. The term homoeopathic cocoa is sometimes applied to mixtures of cocoa with other substances, such as arrowroot. Malted cocoa is a combination of pure cocoa with extract of malt. Navy cocoa is one of the purest preparations of the article, being quite free from husk. The ordinary form contains 20 per cent, of Demerara sugar, whilst the ' soluble ' form has 20 per cent, of white sugar and 20 per cent, of arrowroot. Both forms are to be regarded as preparations of chocolate rather than mere cocoa. Chemical Composition of Cocoa. 1 — The general composition of the cocoa-bean is shown in the following table (Bannister) : COMPOSITION OF COCOA. Analysis of Raw Analysis of Trinidad Nibs Skilled Fresh (Inland Revenue Cocoa-beans Laboratory). (BoussingauU). Water 523 76 Fat 5° - 44 499 Starch 420 3-4 Albuminous matter, soluble ..63 1 „ insoluble .. 69 J " Astringent principle . . . . 671 02 Gum 217 2-4 Cellulose 640 106 Alkaloid 084 3-3 Cocoa-red . . . . . . . ■ 2 20 Undetermined .. .. .. 5'8o 5-3 Ash 275 40 The chief ingredient is ia;, ol which the cocoa-bean contains about half its weight. In the commercial powder, however, there is only about 32 per cent, present, the remainder having been removed by pressure. Cocoa contains a considerable proportion of nitrogen, but it must be carefully noted that not more than 21 per cent. (Wigner) to 32 per cent. (Stutzer) of this is present as proteids, the rest being in the form of amides. Part also is contained in theobromine. 1 For much information on this subject and full bibliography, see United States Department of Agriculture, Division of Chemistry, Bull. 13 ; also a paper by Cohn, Zeit. f. Physiolog. Chem., 1895, xx. 1. See also Allen's ' Commercial Organic Analysis,' vol. iii., part ii. COMPOSITION OF COCOA 3 2 7 Cohn, indeed, found only 7-9 per cent, of true proteid in raw cocoa-beans, using Stutzer's method. The chief alkaloid found in cocoa is theobromine. Theobromine is known chemically as dimethyl-xanthin, and it is closely related to caffeine, which is methyl-theobromine. Cocoa contains from 1 to 2 per cent, of it, or about as much as there is of caffeine in coffee. Cocoa contains also some tannin, though probably not of exactly the same form as that found in coffee and tea. Zipperer 1 places the amount at 5-4 per cent. It seems to be combined with a pigment to which the name of cocoa-red is given, but the exact relationship of the two substances has not been fully determined. Starch is present to the extent of 578 to 15-13 per cent. (Ewell). The proportion of mineral matter is high, amounting in raw cocoa to from i\ to 3J per cent. After the fat has been partly removed, the proportion of ash rises to 4 or 5 per cent. ; or, if alkali has been artificially added, it may amount to 8 per cent. The ash is strongly alkaline, and in the artificial preparations consists chiefly of potash and phosphoric acid. The following table contains the results of some analyses which the writer has made of the commonest forms of cocoa in use in this country : COMPOSITION OF COCOAS. Cadbury's Cocoa Essence Fry's Pearl Cocoa . . , , Pure , , Van Houten's Pure Cocoa Vi-Cocoa Schweitzer's Cocoatina Rowntree's Elect Cocoa Epps's Prepared Cocoa Suchard's Cocoa Clarnico Cocoa Mois- ture. Fat. 39 252 73 158 5-6 256 30 280 6'3 269 4'3 282 65 25'5 49 15-1 47 33'2 5'i 30-6 Nitrogenous Matter tNx6-2 5 ). 209 43 197 205 170 194 180 67 186 22 - o Non-Nitro- genous Constituents other than Fat. 45'2 712 43 2 397 438 418 422 718 367 36-1 Ash. 4-8 I'4 59 88 7-0 63 78 i'5 68 59 Average Composition of a Pure Soluble Cocoa. Moisture Nitrogenous matter Fat Other non - nitrogenous matter Mineral matter 4 per cent. 20 „ 26 40 6 Probable Percentage of Nutrients in such a Cocoi. Proteid 12 per cent. Fat 26 Carbohydrates .. . . 25 „ (?) 1 Quoted by Cohn [loc. cit.). See also Fraser, Jotirn. of Anat. and Pkysiolog., 1883, xviii. 13, and Wynter Blyth, ' Foods,' 4th edit., p. 455. 328 FOOD AND DIETETICS Special attention may be directed to the fact that there is no preparation of pure cocoa which is much poorer in fat than any other. 1 The following additional analyses are by Ewell 2 : Fat. Fibre. Cane- sugar. Ash. Added Starch. Fry's Cocoa Extract 3095 3 89 4-24 None Schweitzer's Cocoatina 3113 37° — 633 Van Houten's Cocoa 29-81 438 864 Blooker's Dutch Cocoa 31-48 3 7 6 606 Rowntree's Cocoa Extract 27 '56 4-42 — 848 „ Powdered Chocolate 25-84 1-30 51 166 Very little arrowroot Epps's Prepared Cocoa 2594 l'5i 26 3-15 Much arrow- root Fry's Diamond Sweet Choco- i860 081 55 116 Much wheat late starch and some arrowroot London Cocoa (unknown maker) 11-13 213 32 282 Much arrow- root Chocolat Menier 21-31 IIO 58 1 40 None Chocolate consists of ground cocoa from which the fat has not been removed, mixed with white sugar, starch and flavourings, such as vanilla, being often added. The inferior varieties are made from unfermented beans, and therefore have a bitter taste. Good choco- late should melt easily in the mouth, and should not sweat out any sugar in the form of a bloom. The taste also should be free from any roughness or astringency. The white part of chocolate creams consists of a mixture of melted cane-sugar and glucose. The following are some analyses of chocolate : Water. Nitrogenous Matter. Fat. Carbo- hydrate. Ash. Chocolat de Sante 3 ■ 10-3 12-5 47' 1 26-8 3 3 18 Van Houten's Chocolate 4 3'9 27-5 668 Plain Chocolate 6 . . 1-89 7'85 6 212 61 g 7 19 Milk Chocolate 8 . . I - 22 9"39 29 98 57'37 2-04 Plasmon Chocolate 8 2-36 18-14 3036 45 46 268 1 Neumann (Arch. f. Hyg., 1906, lviii. 1) concludes that cocoas with about 30 per cent, of fat are to be preferred on all grounds to those with less. They also have the advantage of remaining longer in suspension than those which are poorer in fat. 3 Allen's ' Commercial Organic Analysis,' vol. iii., part ii. 8 Analysis by Atwater and Woods. 4 Analysis by the author. B Analysis in Leyden's ' Handbuch,' i. 109. 6 I '67 = theobromine. 7 7*4 = non-nitrogenous extractives. 8 Analysis by Jago {Joum. of the Soc. oj Arts, January 10, 1902). INFUSED BEVERAGES AND DIGESTION 3 2 9 Chocolate was first used as a beverage in this country about 1657. It was very popular in the time of Charles II., and fetched 6s. 5d. per pound. Influence of Tea, Coffee, and Cocoa on Digestion. The influence of these beverages on salivary and gastric digestion is, on the whole, unfavourable ; of their effects on intestinal digestion we have little exact knowledge ; Roberts considers that they are practically nil. Roberts 1 found that tea markedly inhibits the con- version of starch into sugar by the saliva. If there was even 5 per cent, of tea infusion in the digesting mixture, practically no digestion of starch took place. He attributes this result entirely to the tannic acid in the infusion, but found that tea infused for only two minutes had quite as powerful an effect as when the infusion was prolonged for half an hour. He points out that the addition of a pinch of bicarbonate of soda to the teapot completely suspends the inhibitory effect. Aitchison Robertson 2 confirms these observations as regards tea, but foupd that coffee bad much less influence, and cocoa almost none at all. The most elaborate investigation of the action of these beverages on digestion in the stomach has been made by Fraser. 3 He found that tea and coffee both retard peptic digestion, but the former to a greater degree than the latter, and that Indian tea has a more powerful effect than China. Further, his observations brought out the interesting result that the digestion of different articles is retarded in unequal measure. Thus, the digestion of white of egg, ham, salt beef, and roast beef, was much less affected than that of lamb, fowl, or bread. Coffee, indeed, seemed actually to aid the digestion of egg and ham. He points out that the foods first mentioned are those most commonly eaten at breakfast, the meal with which tea and coffee are usually taken, and he sees in this an unconscious adapta- tion to obviate any disturbance of digestion. He attributes the retarding effect to the tannic acid and volatile oil which these beverages contain, the caffeine itself favouring digestion rather than otherwise. The addition of milk, it is important to note, largely removed the retarding influence of tea. Fraser also found that tea increased the production of gas from all except the salted foods. Coffee did not do this, and therefore, he says, should be preferred to tea in cases of flatulent dyspepsia. Tea also reduces the acid-absorb- 1 ' Digestion and Diet, ' p. 120. a Robertson, W. G. A.,Journ. of Anat. and Physiolog., 1898, xxxii. 615. » Ibid., 1883, xviii. 13. 33° FOOD AND DIETETICS ing power of foods ; coffee has a similar but less marked effect, while cocoa actually increases it. For this reason cocoa is the most appropriate beverage for patients suffering from the acid forms of dyspepsia. Cocoa was found to interfere with artificial digestion, owing to the ' clogging ' action of its fine particles preventing the free access of gastric juice to the food. It is very doubtful, however, whether it would have any such effect under natural conditions. The retarding influence of tea and coffee on peptic digestion has been also established by Roberts, 1 Ogata, 2 and Schultz-Schultzen- stein. 3 The former is of opinion that the tannic acid only accounts for about one-half of the inhibitory effects exerted by tea. On the whole, they are agreed that coffee has less influence than tea, pro- vided it be of the same strength, but, inasmuch as the former is usually a stronger infusion than the latter, its effects in actual practice are equally powerful. Apart from their modifying influence on the chemical processes of digestion, it must be remembered that these beverages sometimes affect the stomach more directly. Thus, the tannic acid and other astringent substances met with in strong infusions of tea may act as irritants to the mucous membrane of the stomach, especially if empty ; and the same is true to an even greater extent of the caffeol and other products produced in the roasting of coffee. It is in this way that these beverages may sometimes excite or keep up a con- dition of chronic gastric catarrh. Cocoa also, owing to the large proportion of fat which it contains, is apt to be irritating to some stomachs, especially as the fat of cocoa appears to be one which is rather difficult of digestion. As regards the practical inferences to be drawn from these experi- ments and observations, it may be said that in health the disturbance of digestion produced by the infused beverages is negligible. Roberts, indeed, goes so far as to suggest that the slight slowing of digestion which they produce may be favourable rather than other- wise, as tending to compensate for too rapid digestibility which refinements of manufacture and preparation have made a charac- teristic of modern foods. In cases where the digestion is enfeebled, on the other hand, and where the ferments are doing their work with difficulty, the presence of these beverages in the digesting mass may make all the difference between failure and success in the process. In such a case, coffee 1 Loc. cit. " Archiv. f. Hygiene, 1885, iii. 204. 8 Zeit. /. Physiolog. Chem., 1894, xviii. 131. USES OF TEA, COFFEE, AND COCOA 33* is probably preferable to tea, and cocoa (provided its fat does not prove a disturbance) is better than either. If tea is taken at all, a good China variety should be selected ; it should be infused for as short a time as possible, and should be taken with milk. 1 Second cups should be eschewed, and it should be drunk after, rather than during, the meal. Tea and coffee should both be avoided — but especially the former — as an accompaniment to meals which make large demands on the peptic powers of the stomach, such, for example, as meals containing much meat. For this reason ' high * and ' meat ' teas are to be condemned. In chronic catarrh of the stomach, coffee is probably more injurious than tea, but in cases of flatulence the former is to be preferred for the reasons already given. As has been previously pointed out, the irritating effects of these beverages on the stomach are more likely to be manifested when the latter is empty. For this reason, the morning cup of tea — ' tea veniente die,' as it has been called — may sometimes prove harmful. On the whole, the effects are probably least when the stomach is neither quite empty nor too full, but contains a moderate amount of easily-digested food — a state of things which, one is glad to say, is pretty well true at ' afternoon tea." As concerns the length of stay of these beverages in the stomach, the following observations have been made : 200 c.c. (ij teacups) of tea remain . . . . . . . . ij hours 9J 3J ,, coffee remain .. .. .. lj| ,, „ ,, „ cocoa made with water remain .. ij ,, ..- milk „ ..24 „ In other words, the larger the amount of solid matter which the beverage contains, and the more it approximates to the characters of a true food, the longer does it tend to remain in the stomach. There are no available observations on the absorption of tea and coffee. If no to 120 grammes (about 4 ounces) of cocoa are taken daily, the loss of nitrogenous matter is about 46 per cent., but of the fat only 4-6 per cent, escapes digestion. The carbohydrates are entirely absorbed. 2 If more than 50 grammes (ten teaspoonfuls) were taken at a time, digestion was always upset. 1 The addition of a little bicarbonate of soda to the contents of the teapot helps to neutralize the injurious effects of the tannic acid. The same result is attained in ' Plasmon tea ' by the incorporation of soluble casein with the leaf, which ' detannates ' the infusion. 2 Cohn, he. cit. Weigimann found that the fat was absorbed to 94-5 per cent., and the nitrogenous matter to 42 per cent., when 195 grammes of cocoa-powder boiled in water were taken in two days. Neumann (Arch. f. Hyg., 1906, lviii. 1) found that cocoa, when given alone, is not nearly so well absorbed as when it 332 FOOD AND DIETETICS Uses of Tea, Coffee and Cocoa. The action of tea and coffee on the body depends entirely upon the tannic acid, caffeine and volatile oil which these beverages contain. The effects of the tannic acid are purely local, and have already been pointed out, when speaking of the influence of tea and coffee on digestion. The caffeine and volatile oil, on the other hand, have a general pronounced physiological action, to which attention must now be directed. Caffeine, like alcohol, is a stimulant, but, unlike that substance, it exerts its effects upon the central nervous system even more than upon the heart. Physiological experiments have shown that after the administration of caffeine the time occupied by nervous processes is shortened, and reflex excitability is increased. At the same time, it removes the sense of fatigue, and is apt to produce sleeplessness. It is interesting to note that these stimulating effects upon the brain were amongst the earliest of the physiological actions of tea and coffee to be recognised. Tradition has it that in the remote ages there was a holy Asiatic, Prince Darma, who spent his nights in meditation on the Infinite. One night his ecstasy was disturbed by sleep. On waking, he was so enraged at his weakness that he cut off his eyelids and flung them on the ground. On visiting the spot some time later, he found that where each eyelid fell a small shrub had grown up. He infused the leaves of the shrub, and ever after- wards, by simply drinking some of the infusion, he was able to keep sleep at bay. That shrub was the tea plant ! A similar tradition as regards the stimulating effects of coffee is thus recorded by Johnston i 1 ' In antique days a poor dervish, who lived in a valley of Arabia Felix, observed a strange hilarity in his goats on their return home every evening. To find out the cause of this, he watched them during the day, and observed that they eagerly devoured the blossoms and fruit of a tree which hitherto he had disregarded. He tried the effect of this food upon himself, and was thrown into such a state of exaltation that his neighbours accused him of having drunk of the forbidden wine. But he revealed to them his discovery, and they at forms part of a mixed diet. When added to a mixed diet, it lessens the absorption of nitrogen from the latter, and the less fat the cocoa contains the more marked is this e'ffect. The proteid of the cocoa can replace part of the proteid in the rest of the diet. Cocoa can therefore claim to rank as a food, although not an important one. In the quantities taken (20 to 30 grams per day) it had no diuretic effect, and the theobromine was only agreeably stimulating. 1 ' Physiology of Common Life,' p. 148. ACTION OF CAFFEINE 333 once agreed that Allah had sent the coffee-plant to the faithful as a substitute for the vine.' As a result of this action on the nervous system, tea and coffee are great aids to mental work, and the former, as De Quincey remarked, will always be the beverage of the intellectual. As a learned Chinaman said of it more than 2,000 years ago : 1 It tempers the spirits and harmonizes the mind. Dispels lassitude and relieves fatigue ; Awakens thought and prevents drowsiness, Lightens or refreshens the body, and clears the perceptive faculties.' The vital centres share in the stimulation produced by caffeine, as well as the brain cortex. After its administration, the respiratory movements are deeper and more frequent, and the heart beats more forcibly and rapidly. It is thus an important aid in combating impending paralysis of these centres in cases of coma. Binz, for example, found that dogs which had been rendered comatose by alcohol could be aroused after the administration of coffee. The fact that coffee is an antidote to alcohol is another justification for its use after dinner. Caffeine, as we have seen, stimulates the heart through the cardiac centre, but it probably has a direct action as well. When adminis- tered in the form of tea and coffee, its action is aided by the fact that these beverages are usually taken hot. The increased force and frequency of the heart's action induces a more profuse flow of urine, 1 and so aids in the removal of waste products from the body. This, along with the stimulation of the nervous system and heart, makes tea and coffee of use in some low forms of fever, conditions in which their administration might with advantage be more extensively adopted. The question has been much debated whether or not caffeine lessens the waste of the body. Some, for instance, have contended that it acts as a kind of drag upon the chemical changes in the tissues, rendering them slower, and so enabling the body to get on with less food than would otherwise be necessary. For this con- tention, however, there is no satisfactory evidence. Indeed, all experiments go to prove the contrary, namely, that caffeine tends to increase rather than diminish tissue waste. 2 It does not prolong life in starvation, although it may perhaps lessen the feeling of hunger. Experiments with the ergograph, too, have shown that tea and coffee are in no sense muscle foods, although they can temporarily 1 Caffeine appears to have a direct stimulating action on the renal cells as well. 2 See Richet's " Dictionary of Physiology,' article ' Caffeine.' 334 FOOD AND DIETETICS increase muscular power by abolishing nervous fatigue, so long, at least, as the muscles are not completely exhausted. 1 The action of the volatile oil contained in tea and coffee has not been very fully investigated, 2 and would appear to be slightly different in the case of the two beverages. It, too, appears to act as a cerebral and cardiac stimulant, and to it, perhaps, some of the unpleasant symptoms, such as headache and giddiness, which afflict those who. like tea-tasters, indulge in large quantities of these beverages are to be attributed. These oils seem also to have an action upon the bloodvessels which is different in the case of tea and coffee respectively, for the former tends rather to dilate the superficial vessels and render the skin moist, while coffee has an opposite action. It is in this way that tea is said to warm the body when cold, by making the circula- tion more brisk, and to cool it when heated, by increasing evapora- tion from the surface. We may conclude, then, that tea and coffee are in no sense foods, in that they can neither build up the tissues nor provide them with potential energy, though they may perhaps act the parts of lubricants in the machinery of the body by diminishing nervous fatigue. It is no doubt this subjective feeling which has led to the very extended use of these beverages by men in all ages and in all countries. When we turn to the question as to what extent these beverages can be indulged in without injury to health, one finds it very difficult to give a definite reply. The part played by personal peculiarity and habit in the matter is very great. It has been pointed out, for example, that the usual result of drinking tea and coffee is to produce wakefulness, but yet there are persons who find their use in the evening conducive to sleep. Some people, again, can drink tea quite freely, but are made ill by coffee or vice versa. Facts like these must be recognised although one is unable to explain them, and they make it impossible to lay down definite rules regarding the dietetic use of tea and coffee. The bad effects usually attributed to an excessive indulgence in these beverages are of two kinds, affecting either the nervous system or the digestion. The increased excitability of the nervous system which they produce may lead to general ' nervousness ' (the patient starts, for instance, on the slightest sudden noise, or, as a tea-taster 1 Schumburg, Archiv. f. Anat. und Physiolog., 1899, Sup. Bd. 289. See also Rivers and Webber, Journ. of Physiolog., 1907, xxxvi. 33. 2 The tendency of recent investigations is to minimize the importance of the volatile oil in tea, or even to throw doubt upon its existence {vide ScottTebb, he. cit.). FOOD VALUE OF COCOA 335 once put it to the writer, he becomes 'jumpy'), tremulousness, palpitation, loss of sleep, giddiness, and depression. The nervous system in childhood is peculiarly susceptible to these effects. The disturbance of digestion which tea or coffee, but especially the former, produces is partly due to a direct interference with the chemical part of the process, as already described, but in part also is brought about indirectly through the nervous system. The dyspepsia which results is of the atonic type, digestion being slow, often accompanied by flatulence and attended by a feeling of sinking or depression and disturbance of the heart's action. Whilst one may fully admit the importance of the part played by tea and coffee in the production of such symptoms, yet the extent to which they prevail has probably been greatly overestimated. 1 It certainly seems an exaggeration to talk, as some people do, of the existence of ' tea drunkenness.' All that one is entitled to infer is that these beverages should be used sparingly by ' nervous ' people and by those whose digestion tends to be feeble and slow. In some cases of gout it is advisable to strike tea and coffee out of the diet, for caffeine is a source of uric acid in the body. Theobromine is so too, but cocoa contains so little of it that it is practically harmless. 2 The place of cocoa in the diet is not really very different from that of tea and coffee. An examination of the chemical composition of cocoa might lead one to suppose that it was of considerable nutritive value. But that would be a mistake. Theoretically, cocoa is a valuable food, but practically it is not, the reason being that so little of it can be taken at a time. In this respect it is exactly com- parable to many of the beef-extracts already considered. The com- bination of cocoa with casein — as in Plasmon Cocoa — increases the nutritive value of the beverage to a certain extent. It takes about 10 grammes (J ounce) of cocoa to make a breakfast- cupful of the beverage, and, assuming the average composition given already, this would yield about 40 Calories of energy. It would, therefore, require fully seventy-five such cupfuls to yield the total amount of potential energy demanded of the body daily — obviously an impossible quantity. Of course, if the beverage is prepared entirely with milk and plenty of sugar it becomes an important ' For an account of the symptoms which may result from an excessive Indulgence in coffee see a paper by Dr. William M. Leszynsky (Med. Record, 1901, lix. 41, 70). See also a paper on ' Tea and the Effects of Tea Drinking,' by Dr. W. Scott Tebb (Cornell and Sons, Borough Road, S.E.) ; and Gouget, ' Le Cafeisme et le Theisme ' {Gaz. des Hop., 1907, lxxx. 1623). 2 Sanitas Health Cocoa contains no theobromine (sold by Battle Creek Sanitarium Co., Ltd., Battle Creek, Michigan, U.S.A.). 336 FOOD AND DIETETICS food, but that is due to the milk and sugar, and not to the cocoa. Chocolate is of more value. Half a pint of milk and 2 ounces of chocolate yield together fully 400 Calories, and 3J pints would suffice to supply all the energy and a large part of the building material required in a day. The action of cocoa on the nervous system is very much less than that of tea or coffee, owing to the small amount of alkaloid which it contains ; indeed, it may be practically ignored. The special prepara- tion known as Vi-Cocoa, on the other hand, has an influence on the brain from the addition to it of a certain proportion of kola. The latter contains a considerable proportion of caffeine as well as a glucoside (kola-red), and it is to these ingredients that its action on the nervous system is to be attributed. 1 Kola is said to possess remarkable sustaining qualities, prolonging muscular contraction and abolishing fatigue ; but its action seems to be uncertain, and the addition of such a drug to a beverage intended to be used regularly is a practice which can hardly be recommended. Paraguay Tea. 2 Paraguay tea or mat6 belongs to the holly order. It contains a small quantity of caffeine along with a peculiar form of tannic acid, glucosides, choline, and ethereal oils. It yields a pale infusion of somewhat bitter and harsh flavour. It is stated to be even more stimulating and sustaining than tea or coffee and less apt to cause indigestion and sleeplessness. Tea and Coffee Substitutes. Owing to the injurious effects of tea and coffee on the digestion and nervous system in some persons, various substitutes for th:m in the diet have been proposed. Amongst these are Ovaltine, 1 which is composed of malt extract, milk, eggs and cocoa, and which con- tains a considerable percentage of lecithin, Life-Belt Coffee 2 (coffee from which the caffeine has been extracted) and Cocacorn 3 (a com- bination of acorns and cocoa). Various Cereal Coffees, made from parched grains of barley, wheat, etc., are also prepared, especially in America. One or other of these substitutes is sometimes found of use in replacing tea or coffee when these are forbidden on medical grounds. 1 See Brit. Med. Journ., 1898, i. 1471 ; Food and Sanitation, February 9, 1895; David Emile, These, Paris, 1894 ; Labesse, "These, Paris, 1897. 2 Paraguay Tea can be obtained from the Apothecaries' Society, Blackfriars, at a cost of 2s. 6d. per pound. Also from the Mate Tea Co., 4, Featherstone Buildings, High Holborn, W.C. 3 Wander, 1 and 3, Leonard Street, City Road, E.C. 4 Life-Belt Coffee Co., Ltd., 71, Eastcheap, E.C. 5 Fassett a^d Johnson, 31, Snow Hill, E.C. I 337 J CHAPTER XIX ALCOHOL The only form of alcohol with which we are seriously concerned in dietetics is ethyl alcohol (C 2 H 6 OH). It is produced, in all the beverages in which it is found, from the fermentation of sugar by yeast, according to the well-known equation : C 6 H ]2 0„ = 2CO a + 2C 2 H 5 OH. (sugar) (carbonic (alcohol), acid) We shall subsequently discover that the special characters of different alcoholic beverages depend to some extent on the particular kind of sugar and yeast concerned in the fermentation. It must also be borne in mind that the process of fermentation as carried on in the manufacture of alcoholic drinks is never such a simple affair as the above equation might induce one to believe. Bye-products are invariably produced as well as alcohol, and the nature and amount of these profoundly influence the character of the resulting beverage. Of all alcoholic drinks, however, it remains true that the principal constituent by which they affect the nutrition of the body is ethyl alcohol. It consequently becomes of the first importance for us to study minutely the effects of alcohol on the body, for upon the results of such study our opinion as to the value or otherwise of alcoholic drinks, both in health and disease, must ultimately rest. I propose, therefore, to devote this chapter to a description of the physiological effects of alcohol. Local Effects of Alcohol. The local effects of alcohol are those of a chemical irritant. If some strong spirit, such as whisky or brandy, is taken into the mouth, a sensation of burning is produced, owing to the irritation of the nerve endings, and by-and-bye the mucous membrane becomes somewhat corrugated and whitened by reason of the removal of water from its surface cells and the coagulation of their protoplasm . 22 33§ FOOD AND DIETETICS Repeated local irritation of this sort is the exciting cause of the pharyngitis and gastric catarrh often observed in those who are in the habit of drinking neat spirits, especially on an empty stomach, where the alcohol can come into direct contact with the mucous membrane. The stimulation of the nerves of the mouth brings about reflexly a profuse flow of saliva, and in this way alcohol may promote salivary digestion, for its retarding influence in the chemical transformation of starch into sugar is so slight that it may be neglected. 1 Effects of Alcohol on Digestion. 2 Arrived in the stomach, alcohol mixes with the gastric contents, and affects the processes of digestion in several very important directions. The first point to notice is that alcohol has, by itself, surprisingly little influence on the chemical processes of digestion. When it is present to the extent of only 1*2 per cent, of the digesting mixture, its influence is rather favourable than otherwise. If the proportion of alcohol is increased to 5 or 10 per cent, the chemical changes of digestion become retarded, but it is only when 20 per cent, of alcohol is present that the process is arrested altogether. 3 This immunity of pepsin to the action of alcohol is very striking, and as a consequence of it one cannot regard pepsin wines as irrational products of pharmacy. It is interesting to note that pancreatic digestion is much more sensitive to alcohol, for if the latter is present to the extent of merely 2 or 3 per cent., the process is distinctly retarded. But digestion is not merely a chemical process. The movements of the stomach walls play a large part in it also. And here the action of alcohol, in dietetic doses at least, is entirely favourable, for it has a wonderful power of increasing the activity of stomach peristalsis. Binz, for example, found that the ad- ministration of eight small teaspoonfuls of brandy at short intervals, for the space of an hour, increased very considerably the rate at which olive oil was discharged from the stomach. He repeated the experiment with similar results in six cases. Alcohol not merely increases the vigour of the stomach move- 1 The presence of even 45 per cent, of alcohol' does not altogether stop amylolytic action (Roberts). This is confirmed by Aitchison Robertson and by Chittenden and Mendel. 2 For an exhaustive study of this subject see ' The Influence of Alcohol and Alcoholic Beverages on Digestion and Secretion,' by Dr. R. H. Chittenden (' Physiological Aspects of the Liquor Problem,' vol. i. ; Boston and New York : Houghton, Mifflin and Co., 1903, p. 137). 3 See Buchner, Deut. Archill, f. Klin. Med., 1881, xxix. 537. See also Chitten- den and Mendel, op. cit. infra. ALCOHOL AND DIGESTION 339 merits : it promotes very powerfully the secretion of gastric juice. 1 This it does not merely by directly irritating the nerves of the mucous membrane, but also indirectly by its presence in the blood after absorption. This indirect action of alcohol is of great im- portance, for it means that even when all the alcohol swallowed has left the stomach, and when any slight retarding influence which it may have exerted on the merely chemical processes of digestion has ceased, it is still able to affect the disintegration of the food by bringing about a more profuse and sustained flow of the digestive juices. 2 When one weighs the very slight retarding influence of alcohol on the chemical part of digestion against its power of promoting the stomach movements and the flow of gastric juice, one finds that the balance is favourable to digestion, and alcohol must therefore be regarded as a digestive stimulant. In accordance with this, direct experiment on the human subject has shown that alcohol in dietetic quantities, e.g., 30 to 40 grammes of brandy (about two tablespoon- fuls), taken before or during meals, actually shortens the time required for the digestion of a meal by about half an hour. 3 Red wines were found to have a similar effect. The net influence, then, of moderate doses of alcohol upon stomach digestion, even in health, is favourable rather than the reverse, while in some conditions of disease its power of exciting the movements of the walls of the stomach and of promoting the flow of gastric juice render it a valuable aid to the digestion of solid food. On the other hand, it is to be noted that in intoxicating doses alcohol interferes with digestion, owing to the general nervous and vascular depression which it brings about. The importance of these conclusions regarding the influence of alcohol on digestion can hardly be overrated, for they explain much of the benefit which is so often derived from the moderate use of alcohol, even in health, and still more in cases of disease. Unlike water, alcohol is freely absorbed by the mucous membrane of the stomach. Chittenden and Mendel found that when the pylorus was ligatured 200 c.c. of a 37 per cent, solution of alcohol disappeared from the stomach of a dog in about three hours, and 1 For some very valuable jexperiments on this subject see Chittenden and Mendel. American Journal of the Medical Sciences, 1896, N.S., iii. 35, 163, 314, 431. and American Journal of Physiology, 1898, i. 164. Full references are given in these papers to the results of other workers. 2 The gastric juice is not merely increased in quantity. The proportion of its solids and its acidity are raised as well (Chittenden and Mendel). 8 Penzoldt and Wolflhardt, Mitnch. Med. Woch., 1890, xxxvii. 608. 22 — 2 340 food AND DIETETICS they add that one may well believe that when 6 or 8 grammes of alcohol are swallowed in the form of wine or beer, 8o to go per cent, of it will have entered the blood within half an hour. This is of great importance, for it means that alcohol requires no digestion, but is able to pass at once into the blood. Hence much of its value as a rapid restorative, even when all digestive power is in abeyance. Alcohol is not only rapidly absorbed from the stomach itself, but power- fully promotes the absorption of other substances. If, for example, a dose of chloral dissolved in water be injected into a stomach the pylorus of which is occluded, narcosis does not follow, but if even very little alcohol is present the usual soporific results soon set in. It is probably for this reason that sleeping-draughts are often much more rapid in their effects when given along with a glass of whisky or brandy, and the rapid action of medicines in the form of tinctures may be explained in the same way. The passage of alcohol out of the stomach into the blood is counterbalanced by a flow of water from the blood into the stomach. The ' endosmotic equivalent,' as it is called, of absolute alcohol for animal membranes is 4"i3, and this means that for every gramme of alcohol which passes in one direction 4-13 grammes of water pass in the other. If, then, alcohol be administered to a patient with a dilated stomach, the result may be that the total amount of fluid in the organ is ultimately increased. On the absorption of foods in the intestine alcohol in moderate quantity does not seem to exercise any effect ';* in other words, one may digest his food better for taking a certain amount of alcohol at meals, but he will not get any more nourishment out of it. Alcohol as a Stimulant. The Latin word stimulus means a whip or spur, and a stimulant is anything which is capable of spurring on an organ to the performance of more work. As a general rule, it may be said that stimulants act either upon the nervous system or upon the heart, and alcohol is one which affects the latter much more than the former. It is doubtful, indeed, whether alcohol can properly be regarded as a nervous stimulant at all. Any symptoms of increased brain activity which it induces are probably to be regarded as the consequence of an increased flow of blood through the brain rather than as the result of any direct action upon the cerebral cells. The stimulating action of alcohol upon the heart, on the other 1 Zuntz and Magnus-Levy, Pfliiger's Archiv., 1891, xlix. 438, and ibid., 1893, liii. 544. ALCOHOL AS A STIMULANT 341 hand, is one of the greatest importance, and results, in health, not only in a greater frequency of contraction, but also in an increased force of each beat. In disease, however, when the heart is beating rapidly, but feebly and ineffectually, the effect of alcohol is often to diminish the number of the beats while improving their force, and as long as these effects are being produced in a case of acute illness, one is tolerably safe in assuming that alcohol is doing good. The stimulating effect of alcohol on the heart would appear to be exerted even before absorption has had time to take place, probably through the medium of the nerves of the stomach, which are, as is well known, in very close relation to those which control the action of the heart. Sometimes, indeed, this reflex action is so powerful that it actually leads to a stoppage of the heart altogether. This would seem to be the explanation of those cases of sudden death which occasionally ensue upon the swallowing of large quantities of strong spirits on an empty stomach, as, for example, when a man drinks a pint of whisky for a wager. After its absorption into the blood, alcohol is able to affect the heart more directly, while at the same time it brings about a dilata- tion of the bloodvessels on the surface of the body, and so diminishes the resistance to the onward flow of the blood. That this diminution of resistance is not, however, the sole cause of the increased rapidity of the heart's action is shown by the fact that alcohol can raise the pulse-rate even although the bloodvessels have been already allowed to dilate by previous division of the spinal cord. The action on the heart, then, is a direct one. Of many observations illustrating these effects of alcohol on the circulation I would only cite one by Parkes and Wollowicz, who found in the case of a man that the administration of from 1 to 7J ounces of rectified spirit daily raised the pulse-rate by ten beats per minute as compared with the period when no alcohol was being taken. They found, moreover, as other observers have found before and since, that this overactivity of the heart was followed by a period of depression in which the beat was both slower and feebler than normal. It is important to bear in mind this after- action of alcohol. It means that the temporary benefits obtained from its stimulating action have to be paid for by subsequent cardiac depression, for alcohol is not, apparently, a food for the heart, but merely a means of enabling that organ to draw for the time being on its reserve of strength. It should be a warning, too, not to begin the administration of alcohol too early in a case of acute disease, 34^ POOD AND DIETETICS lest one arrives at the period when no further stimulation is possible before the crisis is past. 1 It has been said that alcohol tends to dilate the peripheral blood- vessels. This, indeed, is amongst its leading physiological actions, and one the significance of which it would be difficult to overrate, for it explains many of the apparently contradictory effects of alcohol on the body. There is reason to believe, for instance, that alcohol tends to anaesthetize rather than stimulate the brain, but by dilating the cerebral bloodvessels it may so flush the brain with blood that intellectual activity may be temporarily increased before the anaes- thetic effects have had time to manifest themselves. Thackeray is said to have remarked that he got some of his best thoughts ' when driving home from dining out with his skin full of wine.' We need not doubt it, for the statement embodies a physiological truth. It was his skin which was full of wine, for alcohol dilates the surface bloodvessels, and along with them those of the brain also, but by the time he got home one may expect that the anaesthetic effects of the alcohol would have begun to exert themselves and the thoughts would have fled. By flushing the brain with blood, alcohol may produce temporary excitement and aid the imagination, but it ends by dulling the edge of the intellect, and is unfavourable to sustained mental work. Another apparent inconsistency in the action of alcohol which is explained by its effects on the bloodvessels is its influence on the temperature of the body. Alcohol, as we shall see immediately, is a fuel, and by its oxidation in the tissues produces heat, just as it does 1 Since the above was written several more observations on the action of alcohol on the heart and circulation have been published, the results of which, however, are far from uniform. Swientochowski {Zeit.f. Klin. Med., xlvi. 284, 1904) found that after the administration of 25 to 100 c.c. of alcohol of 50 per cent, strength the pulse-rate is increased, but slows down again a little in two or three minutes, without reaching the normal again, however, for at least half an hour. For an hour after its administration blood-pressure is lowered. He found no evidence that it really stimulated the heart, but believes that the latter is depressed by alcohol, as are all vital functions. Cabot (Boston Med. and Surg. Journ., 1904, cl. 281) is convinced from his observations on patients that no effect of alcohol upon the heart or blood-pressure is demonstrable, although he does not go so far as to infer that it is useless in disease. Dixon, chiefly as the results of experiments on rabbits, arrives at the following conclusions (Journ. of Physiol., 1907, xxxv. 346) : 1. In moderate doses and well-diluted alcohol has little effect on the rate of the heart ; in large doses it slows the heart through the vagus. The failing heart is accelerated by alcohol. When taken by the mouth and in concentration it reflexly quickens the beat. 2. In moderate doses it causes dilatation of the superficial vessels and some slight constriction, which after large doses is followed by dilatation, of internal vessels. 3. In moderate doses alcohol increases the activity and output of the heart. ALCOHOL AND BODY TEMPERATURE 343 in a spirit-lamp ; but by dilating the surface bloodvessels it causes more heat to be given off by radiation than its own combustion produces, so that the net result is that the temperature of the body is lowered. 1 It is all the more essential to grasp this fact, for the reason that the very flushing of the skin with blood produces a deceptive feeling of warmth, and for that reason alcohol is often taken 'to keep out the cold.' That is a great mistake. Alcohol does not ' keep out the cold,' but lets out the heat of the body, and consequently the consumption of spirits is a very bad means of fortifying one's self to meet a low external temperature, as was found out by the Arctic explorers long ago. By unlocking the surface bloodvessels and allowing of the escape of heat, alcohol often renders great service in the treatment of fevers ; but in health the paralysis of the heat-regulating mechanism which it induces may be dangerous, or even fatal, and one finds as a matter of fact that persons who are frozen to death, in this country at least, have (He suggests that this may be due to its action as a food.) In intoxicating doses it depresses the heart. 4. When administered to animals which show signs of circulatory failure, alcohol raises blood-pressure mainly on account of its effect on the heart. In normal animals and in man, whilst the systolic pressure may rise a little or remain unchanged, the diastolic tends to diminish ; in other words, the difference between the systolic and diastolic pressures tends to increase. Abel (' Physiological Aspects of the Liquor Problem,' edited by John S. Billings; Boston and New York : Houghton, Mifflin and Co., ii. 91) summarizes the experimental evidence regarding the action of alcohol on the vascular apparatus as follows : ' 1. Alcohol as such, when introduced into the circulation with the avoidance of local irritation, is not a circulatory " stimulant." ' 2. Alcohol in moderate quantities — say a pint of wine — has no direct action on the heart itself, either in the way of stimulation or depressing it. This state- ment is based on the results of laboratory experiments extending over short periods of time only, and does not imply that it holds for the steady daily use of alcohol in this quantity. ' 3. In moderate quantities it has no appreciable effect on the blood-pressure. When a change in this becomes evident it is always in the direction of a fall. '4. By virtue of its local action on mucous membranes and on the brain, alcohol is capable of affecting the several parts of the vascular apparatus in such ways that the term "circulatory stimulant" may be applicable. The most frequent of these indirect effects is a quickening or slowing of the pulse-rate. Such indirect influences must not be allowed to hide the true character of alcohol, which is always depressant in kind. ' 1 This only seems to occur in appreciable degree, however, when the alcohol is taken in intoxicating doses. On this point Atwater and Benedict remark : 'The theory that the energy yielded by alcohol is lost by the increased heat- radiation, like the theories that alcohol is not oxidized in the body, and that it prevents normal oxidation of other material, was suggested by observed facts. In each case the facts were suggestive, but not conclusive. Under crucial tests they are found to fail ' (' Physiological Aspects of the Liquor Problem,' ii. 297). 344 FOOD AND DIETETICS usually met with that fate through their having been in a state of intoxication when the cold overtook them. On the other hand, if one has been already exposed to cold, and the blood has been driven into the internal viscera, and is stagnating there and about to produce congestion, the timely administration of alcohol may save the situation by once more bringing about a proper distribution of the blood. 1 By all means, then, take alcohol on coming indoors when wet or chilled, but carefully avoid it when about to proceed out to meet the frost or rain. There can be no doubt that prolonged over-indulgence in alcohol may cause the vascular paralysis of which we have spoken to become permanent, whence the bloated look and purple nose of the drunkard. In such a case the beneficial effects which should other- wise be obtained from the administration of alcohol in acute disease are no longer manifested. The heart and bloodvessels have been so often stimulated that they have ceased to respond to the spur, and the patient often pays the penalty with his life. Influence of Alcohol on Metabolism. Alcohol is a protoplasm poison or anesthetic, but is itself easily burnt up in the body. That is the key to the proper understanding of its action on metabolism. Let us see more exactly what the statement means. We have already seen (p. 22) that the cells of the body may be regarded as being bathed in fluid which contains in solution particles of proteid, of carbohydrate, and of fat, and we have further learnt that there is reason to believe that these are broken down by the cells with different degrees of facility, proteid being most easily destroyed, then carbohydrate, and lastly fat. If now alcohol gets access to the cell and partially paralyzes or anaesthetizes it, the cell will lose its power of breaking down those compounds, such as fat, with which it has, even in a condition of full activity, most difficulty in coping. Alcohol, then, saves fat from combustion ; in other words, it is a fat-sparer. It also appears, though with greater difficulty, to be able to spare carbohydrate, but it is exceedingly doubtful whether it is ever able so far to paralyze the cell as to destroy its power of dealing with proteid. This action of alcohol on cellular activity is quite in keeping with what we know of the effects of other cell poisons. Arsenic, for instance, seems to impair the fat- destroying power of the cells, while there is some reason to suppose that lead interferes with their ability to break down proteid, and so 1 See also Brunton, ' The Physiological Action of Alcohol," Practitioner, 1876, xvi 57, 118. ALCOHOL AS A FOOD 345 may predispose to gout, while hydrocyanic acid is the most powerful protoplasm poison known, and by paralyzing the activity of the cells in every direction at once leads to death. Alcohol, then, certainly spares fat and sometimes carbohydrate, but in so doing it is itself consumed, and yields heat and energy to the body. Of this fact, once much disputed, there is no longer any doubt, and it at once entitles alcohol to rank as a food. 1 Careful experiments have shown that the complete combustion of 1 gramme of alcohol in the body yields 7 Calories of energy ; in other words, 131 grammes of alcohol will yield as much heat as 100 grammes of fat, which means that 1 ounce of alcohol supplies as much fuel as 1 ounce of butter 2 (about 200 Calories). This statement must not be misunderstood. It does not follow from it that alcohol is as good a source of heat in the food as fat. Quite the contrary is the case, for, as we have already seen, by dilating the surface bloodvessels, alcohol may cause more heat to be lost than it is itself capable of producing. Further, alcohol is rapidly burnt up, and the heat which it yields is quickly dissipated, while fat produces heat in a slower and more equable fashion. In large doses the general paralysis of cellular activity which alcohol produces is so great that heat production is diminished at the same time as heat loss is increased, and the final result is a great lowering of the body temperature, which may even amount to 15 F. There is still less reason to regard alcohol as a useful muscle food. Even granting that it can be oxidized in the muscles in such a way as to be capable of yielding energy, any value which it may possess in virtue of that is seriously counterbalanced by the paralyzing effect which it exerts on nerve cells, dulling the sense of exhaustion which is Nature's warning, so that, as experience has shown, the con- sumption of alcohol during muscular work tends to hasten rather than delay the onset of fatigue. 3 Seeing that alcohol in sparing fat and carbohydrate is itself oxidized, one is not surprised to learn that its administration does 1 80 per cent, of fat. 2 See Scarborough, ' Alcohol as a Food,' Yale Med. Journ., January, 1910, p. 239. 8 See ergographic experiments by Destree, Quarterly Journal of Inebriety, January, 1899; also Schnyder, Pfluger's Archiv., 1903, xciii. 451. Later observa- tions by Rivers ('Influence of Alcohol, etc., on Fatigue'; Edward Arnold, 1908) show that in doses of 5 to 20 c.c. of pure alcohol there is no effect on muscular fatigue ; with doses of 40 c.c. the results are inconstant. On the whole, alcohol seems to have a depressing effect on mental work, and a stimulating one on muscular work. The consensus of opinion among Alpine climbers (' Alcohol and Alpinism,' by Dr. L. Schnyder, translated by E. J. Richards ; Edinburgh and London : ■ William Green and Sons, 1910) is that alcohol should be avoided during muscular exertion, although it is believed by many to have a restorative effect after the work is over. 346 FOOD AND DIETETICS not increase or diminish either the intake of oxygen or the output of carbonic acid gas. 1 On the other hand, if the amount of fat or carbohydrate in the diet is already insufficient for the needs of the body, alcohol is able to supplement them by acting as a source of heat. Atwater found that from one-fifth to one-seventh of the total Calories of the diet could be thus replaced by alcohol, and this explains the observation of Hammond, that when he added alcohol to a diet on which he was losing weight the loss was immediately stopped. 2 Anstie 3 has recorded some striking instances of a similar sort in which alcohol seemed to act as a true food. He kept patients alive during acute illness for many days on nothing but large quantities of brandy, and found that they had not emaciated during that time nearly so much as they would have done if they had been merely living on their own tissues. Nor is this surprising, for the amount of alcohol (12 ounces of brandy) supplied daily was capable of yield- ing close upon 1,000 Calories to the body. Much discussion has taken place amongst physiologists as to whether alcohol is or is not a proteid-sparer. It would be impossible to summarize the evidence on each side of the question here, 4 but it may be stated in brief that the results of the latest and most trust- worthy experiments tend to show that alcohol undoubtedly possesses a limited power of lessening nitrogenous waste. Its influence in this respect, however, is far less than that of carbohydrates, and less even than that of fats, and seems to vary under the influence of condi- tions which are not fully understood, and to depend also, to some extent, upon the personal peculiarities of the subject of experiment. The point is of some importance, for it has been believed by many that the administration of alcohol has the power of checking the rapid waste of nitrogenous tissue which goes on in fever. Unless, however, the action of alcohol is very different in fever from its behaviour under healthy conditions — a proposition for which there is no real evidence — one is not justified in assuming that it has any appreciable influence in that direction. As regards the general influence, then, of alcohol on metabolism, we may safely conclude (i) that it is burnt up in the body, sparing i Zuntz, Fortschr. d. Med., 1887, v. I, and Geppert, Arch. f. Exper. Path. u. Pharmak., 1887, xxii. 367. 2 ' Physiological Memoirs,' 1863, p. 47. s ' Stimulants and Narcotics,' London, 1864. 4 For a full discussion of the subject see ' An Experimental Inquiry regarding the Nutritive Action of Alcohol,' by Atwater and Benedict {Nat. Acad, of Sciences, 1902, vol. viii., Memoir 6); also Neumann, Arch. f. Hygiene, 1902, xli. 85; Kass'owitz, Pfluger's Archiv., 1902, xc. 421 ; and Goddard, Lancet, 1904, ii. 1132, 5 Rosenfeld, however, finds (Abst. in Maly's Jahres-Bericht Thier-Chemie, xxxvi. 674) that alcohol has no injurious effect on metabolism, and is a better proteid sparer than an equal quantity of sugar. ALCOHOL AS A PROTOPLASM POISON 347 fat and carbohydrate in the process, but that (2) the weight of evidence is against the view that it has any important power of diminishing nitrogenous waste. The question next arises, At what rate does the combustion of alcohol in the body go on ? Is it so rapid that all of it is decom- posed, or is there time for some of it to be eliminated unchanged ? The reply to these questions is that much depends on the quantity of alcohol taken. In non-intoxicating doses, exceedingly little, not more than from 1 to 3 per cent, at most, passes off from the body unchanged. 1 If, on the other hand, the quantity consumed is sufficient to produce intoxication, the amount of alcohol which escapes combustion may rise to more than 10 per cent, of the whole dose. Whenever the proportion of alcohol circulating in the blood becomes greater than the cells can rapidly decompose, its effects as a protoplasm poison become manifest. In their extreme form those effects culminate in intoxication, which is really a condition of cell paralysis, so that the expression ' paralytic drunk ' has a truer physiological meaning than those who use it commonly suppose. The brain cells seem to be peculiarly sensitive to the paralyzing action of alcohol, so that the brain is the first to show the effects of an overdose. It is paralyzed from above downwards, the higher centres being affected first. Now, the highest centres are the controlling centres of the brain, and hence loss of control, intel- lectual, emotional and muscular, is the earliest fact of alcoholic intoxication. It is only in the extreme degrees of the condition that the ' driving centres ' of the brain, the centres of organic life which maintain the action of the heart and provide for respiration, become involved in the paralysis, and the condition then is one not merely of intoxication, but of coma, and threatens life itself. The bad effects of alcohol taken in quantities sufficient to produce intoxication are too apparent to require to be insisted upon. It must be remembered, however, that the habitual consumption of alcohol in quantities which, though insufficient to produce any of the outward and visible signs of intoxication, are yet beyond the immediate oxidizing power of the cells, may end by playing havoc with the tissues. Here, again, the brain seems specially liable to suffer, probably owing to its being one of the most highly organized and delicate tissues in the body. As the result of chronic alcoholism 1 See Anstie, ' Final Experiments on the Elimination of Alcohol from the Body ,' Practitioner, 1874, xiii. 15. See also Binz's 'Lectures on Pharmacology,' and At water and Benedict, lot. cit., and Goddard, loc. tit. 348 FOOD AND DIETETICS it becomes the seat of various degenerative changes to which the motor centres seem less resistant than the sensory. I think, too, that one can recognise in the habitual alcoholic a certain degree of paralysis of the moral perceptions, and in special a loss of the sense of truth. Throughout the body generally the presence of even a slight amount of undecomposed alcohol leads to a diminution of the chemical energy of the cells, which interferes with the ordinary course of metabolism, and may result in chronic disease. The metabolism of fat is, for reasons already pointed out, most apt to be interrupted, and hence alcoholism is a common cause of fatty degenerations and an important factor in many cases of obesity. By delaying the decomposition of carbohydrates, it aids in the productions of some forms of diabetes, and there can be no doubt that it plays a large part in that alteration of proteid metabolism which seems to be the basis of gout. 1 It seems reasonable, also, to suppose that the excretion by tho kidney and other organs of undecomposed alcohol may act as an irritant and bring about changes in structure, which may end in serious interference with the discharge by the affected organ of its normal functions. It is in this way, for example, that the habitual consumption of more alcohol than can be decomposed in the body may produce chronic nephritis. All these considerations bring home to one the very great importance of ascertaining, if only approximately, how much alcohol can be so completely oxidized in the body that there will be none left over to exercise upon the tissues those injurious influences of which we have just been speaking. Experiments carried out with a view of determining this point have shown that i to i£ fluid ounces of absolute alcohol is about the amount which can be completely oxidized in the body in one day, and in such a way that none of its paralyzing or narcotic effects are manifested, and no unchanged alcohol appears in the urine (Parkes). 2 This quantity of alcohol would be contained in the following amounts of some of the commoner alcoholic drinks : Brandy or whisky (50 per cent, alcohol) 2 fluid ounces, or 1 glass. Port, sherry, and other strong wines (20 per cent, alcohol) . . . . . . 5 „ „ or 2 J glasses. Claret, hock, champagne, and other weaker wines (10 per cent, alcohol) . . 10 ,, „ =1 tumblerful. Bottled beer (5 per cent, alcohol) .. 20 „ „ = 1 imperial pint. 1 See also Von Strtimpell, ' Ueber die Alkohol Frage vom Aerztlichen Stand- punkt.' aus 65ten Versamml. deut. Naturforscher zu Niirnberg, 1893, p. 97. 2 Goddard (loc. cit.) found that if alcohol was administered to dogs to the extent of Y iis of the body weight it was almost completely oxidized. If the same proportion holds good in the human subject, a man of average weight (150 pounds) ought to be able to oxidize about 3 ounces. ALCOHOL IN HEALTH 349 Whilst we may admit the probable accuracy of the data on which these calculations are founded, two modifying factors have to be con- sidered. The first of these is the question of idiosyncrasy. There can be no doubt that personal peculiarity plays a very large part in determining the amount of alcohol which can be consumed by any given individual without injury to health. Some persons seem to be able to burn up alcohol more rapidly and completely than others, for reasons which do not seem to be connected with any determinable peculiarity of physical organization. Certainly every one must have known persons who were able to go on consuming daily a far larger quantity of alcohol than the standard above laid down, and yet with- out their health being appreciably impaired by the indulgence. Indeed, when one recalls the drinking exploits of our grandfathers and the prowess of the ' three-bottle men,' one is almost tempted to think that the power of our tissues to oxidize alcohol has actually undergone a decline. Apart from mere peculiarities of constitution, it must be obvious that the surroundings and habits of each individual must affect very greatly the amount of alcohol ip which he can indulge with safety. The rapid oxidation which is the result of an active, open-air life, for example, enables an amount of alcohol to be consumed with impunity which would work disastrous con- sequences in one of sedentary pursuits. The other factor which must influence any calculation as to the amount of alcohol which can safely be consumed daily is the form and mode in which the alcohol is taken. It will be generally con- ceded that the same quantity of alcohol is less likely to be injurious if taken in a dilute than in a concentrated form. It must be evident also that an amount of alcohol which would be harmful if swallowed at one time may be free from risk if spread evenly over the day. The danger to be avoided is flooding the circulation at one time with an amount which it is beyond the power of the cells to oxidize. Use of Alcohol in Health. We have seen that one cannot deny to alcohol the right to be regarded as a ' food ' in the scientific sense of the term. We have also seen, however, that it cannot be regarded as a food of any great practical importance, for it is merely able to replace a certain amount of fat, and perhaps also of carbohydrate, in the body, while its secondary effects on the nervous and vascular systems counteract, to a large extent, the benefits derived from the production of heat and energy by its oxidation. As a food, also, alcohol is open to the 350 FOOD AND DIETETICS additional objection of being very costly. Even in Bavaria, the land of cheap beer, it has been calculated that alcohol, in that, its least expensive form, is eight times dearer than bread, from the point of view of the amount of heat yielded. It has been shown that alcohol is not favourable to the production of sustained muscular effort, and that it may even do harm by paralyzing the sense of fatigue which is the natural check on exces- sive exertion. Nor can it be said that it is favourable to the produc- tion of perfectly healthy brain-work. An interesting book 1 was published a few years ago in which were gathered together the results of the personal experience of leading men in literature, science and art on the effects of stimulants as aids to intellectual work. It is interesting to note that, out of the 124 individuals consulted, none ventured seriously to recommend alcohol as an aid in the performance of mental labour. As Abel has said : 2 ' He who has mental labour of an exacting kind to perform and he upon whom great responsi- bilities devolve, is forced, if he would be at his best, to use alcohol as a restorative agent only at the proper season ; he must behave to it as he does to many other pleasures and luxuries in his environ- ment.' A recent census in America yielded much this same result. 3 We may conclude, then, that alcohol is an unnecessary article of diet in complete health, although, if used within the limits already indicated, it cannot be said to be harmful, and may even, indeed, be beneficial; for, as Matthew Arnold has said in the book already referred to, ' wine used in moderation seems to add to the agreeableness of life — for adults, at any rate — and whatever adds to the agreeable- ness of life adds to its resources and power.' It is in conditions just short of health, however — in old age, over- work and fatigue — that the beneficial effects of alcohol become most marked. They may be traced almost entirely to its favourable influence on digestion, and hence a good rule for the use of alcohol in all conditions short of actual disease is to take it only at meals, and in such quantities as are found to improve the appetite for food and the capacity for digesting it. As regards the form in which it should be used, beer seems most natural for youth, wine in middle life,' whilst spirits may be reserved for the aged. 1 1 ' Study and Stimulants,' A. A. Reade (Simpkin, Marshall and Co., 1883). 2 'Physiological Aspects of the Liquor Problem,' ii. 165. 3 Ibid., vol. i. 4 In the Contemporary Review for 1878 and 1879 there will be found a very interesting discussion of the alcohol question, in which several distinguished physicians and surgeons took part. The opinion of most of them was that the moderate use of alcohol in health IS harmless, if not indeed actually beneficial. ALCOHOL IN DISEASE 351 Use of Alcohol in Disease. Just as the effect of alcohol on the digestion is the test of its value in health, so its effects on the circulation and nervous system are the criterion of its usefulness in most cases of acute disease. As long as the efficiency of the heart is improved by its administration, alcohol is doing good. In fever, its power of lowering temperature and its calming influence on the brain are also of use, while it may, perhaps, check somewhat the tissue waste which is so marked a feature of acute fevers, although we have seen reason to doubt this — at least, as far as the nitrogenous tissues are concerned. To this point, however, we shall return in another chapter (p. 484). There are grounds also for the belief that alcohol actually increases the resisting power of the body to the poisons of certain diseases — such, for example, as septic fevers. I am aware that laboratory experiments 1 have shown that rabbits in a state of intoxication are actually less resistant than normal to certain organisms, such as the streptococcus of erysipelas, but the dose of alcohol administered was excessive ; and to set against these results we have the clinical In Dr. Wilks' paper the view that alcohol is essentially a narcotic rather than a stimulant is strongly presented, while Dr. Moxon deals in the most interesting manner with its effects on the mental faculties. The conclusions of Dr. Murchi- son, which are not, however, in complete harmony with those of most of the other contributors, are as follows : 1. A man in good health does not require alcohol, and is probably better with- out it. Its occasional use will do him no harm ; its habitual use, even in moderation, may, and often does, induce disease gradually. 2. There are a large number of persons in modern society to whom alcohol, even in moderate quantity, is a positive poison. 3. In all conditions of the system characterized by weakness of the circulation, the daily use of a small quantity of alcohol is likely to be beneficial, at all events for a time. Sir James Paget wrote : ' I cannot doubt, with such evidence as we have, that the habitual moderate use of alcoholic drink is generally beneficial, and that in the question raised between temperance and abstinence the verdict should be in favour of temperance. ' On the whole, the views presented by these writers may be regarded as fairly representing contemporary medical opinion on the subject. 1 See Abbott, Journal of Experimental Medicine, 1896, i. 447. Parkinson (Lancet, 1909, ii. 1580), as a result of experiments on the relation of alcohol to immunity, arrives at the following conclusions : 1. Alcohol in small quantities has no action upon the phagocytic activity. 2. It has no action on the phagocytic activity until it is present in 125 per cent, strength. 3. Small quantities of alcohol injected into rabbits may stimulate the produc- tion of antibodies temporarily. 4. A large dose of alcohol lowers the opsonic index for twenty-four hours. 5. Continuous moderate doses of alcohol cause a permanent lowering of the opsonic index. 6. The reacting mechanism to vaccines is much less effective in alcoholized rabbits than in normal rabbits ; the difference is still more marked when living micro-organisms are used. 352 FOOD AMD DIETETICS experience of good observers, who regard alcohol as being actually an antidote to acute erysipelas. In some chronic diseases, such as diabetes, alcohol is used as a real food to replace a certain amount of carbohydrate in the diet, whilst in others it is chiefly its tonic influences on digestion whicn one seeks to obtain. We shall have occasion to study its uses in these different directions in detail in subsequent chapters. £353 J CHAPTER XX ALCOHOLIC BEVERAGES : SPIRITS AND MALT LIQUORS Before proceeding to the study of the alcoholic beverages in detail, it may be well to describe the different ways in which the amount of alcohol which they contain may be stated. This is all the more important as an inaccurate use of terms may lead to some confusion. In this country the standard employed is usually what is known as proof spirit, and an alcoholic liquor is said to be so much above or so much under ' proof.' Proof spirit is a mixture of alcohol and water, which contains 49/24 per cent, of the former by weight (i.e., 100 grammes contains 49/24 grammes alcohol 1 ), and 57*06 per cent. by volume (i.e., 100 c.c. contains 57 - o6 c.c. alcohol). ' The name proof spirit owes its origin to the practice in vogue during last century, of testing the strength of samples of alcohol by pouring them on to gunpowder and applying a light. If the sample contained much water the alcohol burned away, and the water made the powder so damp that it did not ignite ; but if the spirit were strong enough the powder took fire. A sample which just succeeded in igniting the powder was called proof spirit ' (Perkins and Kipping). Spirits are described as being over proof -when they are stronger than proof spirit, and under proof when they are weaker. Thus, 20 over proof means that 100 volumes of the spirit contain as much alcohol as 120 of proof spirit, and 20 under proof means that 100 volumes only contain as much alcohol as 80 of proof spirit. Instead of using proof spirit as the standard, it is more convenient to speak of the amount of alcohol as being so much per cent. The percentage may further be stated either in weight or in volume. Five per cent, of alcohol by weight means, strictly speaking, that 100 grammes of the liquid in question contain 5 grammes of alcohol ; but more usually the expression is used for weight in volume — ■ 1 100 grammes of proof spirit has a volume of about no c.c, for shrinkage occurs when water and alcohol are mixed. 23 354 FOOD AND DIETETICS i.e., 5 grammes of alcohol in ioo c.c. Five per cent, by volume means 5 c.c. in every hundred, and is equivalent to about 4 per cent, by weight. 1 The percentage of alcohol by volume in some of the commoner alcoholic beverages is roughly as follows : Rum . . "J Port . . 25 per cent. Hock . . 10 per cent. Whisky . . V43 per cent. Sherry ..21 „ Claret . . 9 „ Brandy . . J Champagne 10 to 15 per Bottled beer 7 „ Gin • • 37 11 cent. Lager beer 4 „ Spirits. Spirits are obtained by the fermentation of various saccharine substances, the alcohol and other volatile bodies produced being separated by distillation. It is this fact of their being the products of distillation which gives to spirits their high alcoholic strength, and distinguishes them from all other alcohol-containing beverages. Almost any substance capable of yielding a fermentable sugar may form the basis of fermentation. Amongst the substances most commonly used in this country are malted and unmalted barley, maize, rice, sugar, and molasses. In some parts of Europe, and especially in Russia, potato starch is largely employed for the purpose. All of these substances yield alcohol on fermentation, but in addition various bye-products make their appearance during the process, and it is to the presence of these that the characteristic flavour of the different spirits is due. Thus, the bye-products of the fermentation of malted barley give rise to the flavour of whisky, those of molasses to the flavour of rum, and those of the grape to that of brandy. By means of patent stills the bye-products can be almost entirely separated from the alcohol with which they are mixed, and the result is an almost pure form of spirit, the origin of which can scarcely be told, for which reason it is called silent spirit. By suitable flavouring the artful manufacturer can make this the basis of almost any spirituous drink. Amongst the bye-products of fermentation there are usually found alcohols which are higher homologues of ethyl alcohol — e.g., propyl, butyl, and amyl, and to a mixture of these the term fusel-oil is often applied. There is some reason to believe that fusel-oil is the product of a later fermentation which takes place after the alcoholic fermentation is completed, and it appears to be produced in larger quantity at high temperatures than at low. We shall see imme- diately that fusel-oil and the other bye-products met with in spirits 1 c.c. alcohol in 100 vols, x o'8=grammes in 100 vols. Grammes alcohol in 100 vols, x 1 '25 = c.c. in 100 vols. „ ,, in 1 litre X7 = grains per gallon (6 bottles). SPIRITS 355 have effects on the body in health and disease only second to that of the ethyl alcohol itself. The annual consumption of all spirits per head in this country in 1890 1 was — England, £ gallon ; Ireland, 1 gallon ; Scotland, 1 J gallons. Whisky. Whisky has been defined by the Chairman of the Inland Revenue Board as ' a spirit made from malt or malt and grain, and distilled in pot-stills.' In the United States Pharmacopoeia it is described thus : ' A spirit obtained from fermeuted grain by distillation, and containing from 48 to 56 per cent, by volume of alcohol. It should be free from disagreeable odour, and not less than two years old.' It is important to distinguish clearly between genuine ' malt whisky,' which is made in 'pot-stills,' and 'grain whisky,' which is pre- pared in ' patent stills.' The bulk of ordinary whisky as it reaches the consumer is probably a blend of these two, grain whisky usually predominating. (a) Malt whisky is prepared from malted barley which is first carefully dried. In many Highland distilleries peat is used as the fuel for drying, and some of the characteristic flavour of such whisky is believed to be derived from the peat smoke. After being dried, the malt is made into a mash, and here, just as we shall see is true of beer, the nature of the water used seems to have some influence on the character of the final product, soft water giving the best result. The mash is then fermented much as in the making of beer, only the process is allowed to go on longer. When fermentation is complete, the fermented mash or ' wash ' is distilled in the old- fashioned pot-still. This is the form of still which is by far the most commonly used in Scotch and Irish distilleries. It is made of copper, and the volatile products are condensed in a simple ' worm,' no attempt being made to separate the spirit from the bye-products. The still is heated over an open flame. This is a point of some importance, for it causes some of the sugary substances in the wash to become slightly charred, and there is produced in this way, amongst other things, the substance furfurol, the presence of which is one of the chief distinguishing characteristics of pot-still whisky. The first product of the distillation is called low wines. These are 1 Report of the Select Committee on British and Foreign Spirits. For fuller statistics see a paper in the Journ. Royal Statistical Society, igoo, lxiii. 272 (summarized in British Medical Journal, 1900, i. 1041). 2 The Royal Commission on Whisky and other Potable Spirits, which reported in 1909, however, concluded that the term ' Whisky' may legitimately be applied to the product of a patent still also, 23 — 2 356 FOOD AND DIETETICS redistilled, and yield (i) ' fore-shots,' (2) ' clean spirit,' or whisky, (3) ' feints ' ; the residue left in the still being the ' spent lees.' The fore-shots and feints both contain much of the bye-products of fermentation, and are redistilled, the distillate being added to the clean spirit, or whisky. It must be noted that no fusel-oil is obtained separately by this method of distillation, and the product consists of alcohol plus some of the bye-products of fermentation. The whisky thus produced has an alcoholic strength of from 13 degrees to 50 degrees over proof, but before bonding it is usually reduced in Scotland to 1 1 degrees and in Ireland to 25 degrees over proof. The bye-products — chiefly aldehydes — which it contains give it, when young, a raw, harsh and disagreeable taste, but after keeping for some years in wood it mellows greatly, and the harsher the taste when young, the more full flavoured the whisky when matured. What the exact nature of the changes is by which the improve- ment which whisky undergoes in wood is brought about we do not yet fully know. This we do know, however, that the percentage of alcohol diminishes, 6 to 8 per cent, of proof spirit being lost by five years' storage. On the other hand, the fusel-oil does not seem to undergo diminution, in spite of frequent statements to the contrary. 1 Irish pot-still whisky differs from Scotch in being prepared usually from a mixture of malted barley with unmalted grain (barley or maize), and the malt is not dried over peat. Otherwise the manu- facture of the two is very similar. (b) Grain Whisky. — This is the form of whisky most commonly distilled in England. It is made from a mixture of grains (barley, rye and maize), with just a sufficiency of malt to convert their starch into sugar. More important than this distinction, however, is the fact that it is distilled by steam and in a patent (Coffey's) still in such a way that the bye-products of fermentation (fusel-oil, etc.) are, to a large extent, separated from the. ethyl alcohol. The result is that the raw product has much less flavour than young malt whisky, and is sooner ready to go into consumption. When run off the still it is almost colourless and has an alcoholic strength of 60 degrees over proof, but is usually diluted to 1 1 to 1 2 degrees over proof before bonding. It acquires a yellowish colour from being stored in old sherry-casks. 1 See Dr. Bell's evidence before the Select Committee on British and Foreign Spirits, 1890-91. Allen, however, does not agree with this. He considers that some of the fusel-oil is converted into volatile ethers. WHISKY 357 As regards the main differences between the two varieties of whisky, I would emphasize — r. That patent-still whisky contains much less of the bye-products of fermentation (including fusel-oil) than pot-still whisky, and is therefore much purer. 2. That as a consequence of this patent-still whisky does not improve nearly so much on keeping as the other variety. It follows from this that a young patent-still whisky is much better to drink than young malt whisky, but that the latter, when fully matured, has a fuller and pleasanter flavour than the former. It is absurd to object to grain whisky on the ground that it contains more fusel-oil than malt whisky, for just the reverse is the truth. After removal from bond, whisky is diluted — or ' broken down,' as it is termed in the trade — by the addition of water. The legal limit of dilution is 25 degrees under proof (42-7 per cent, alcohol by volume), and the majority of vendors may be trusted to take full advantage of the permission, so that the ordinary whisky sold in bottle is of this strength ; indeed, of fifty-one samples of public-house whisky taken from all over the country, the strength was from 15 to 25 under proof in all but two instances. 1 In other words, we shall not go far wrong if we regard a glass of whisky as containing rather less than half a glass of absolute alcohol. As already mentioned, most commercial whiskies are blends, and not the product of one distillery at all. Grain whisky is often used as the basis of the blend, a certain proportion of malt being added to give flavour. Even when the blend contains as much as 90 per cent, of grain whisky, it is often sold as ' genuine malt.' 2 The public taste at present is certainly in favour of a mild-flavoured whisky, hence the large use of grain spirit in blends. Potheen is the product of illicit stills, and, being usually made from molasses, has the characteristics of rum rather than those of true whisky. Brandy. If whisky be regarded as distilled beer, brandy may be spoken of as distilled wine. 1 Select Committee's report. 2 There can be no question that such a practice is unfair to the consumer, for whatever may be said of the relative merits of malt and grain spirit, everyone has a right to know the nature of the whisky he is buying. It would be well, therefore, if the law should insist that the character and origin of the contained spirit should be printed upon the label of the bottle. (See 'The Practice of Substitution in the Spirit Trade,' Lancet, 1903, i. 542.) 358 FOOD AND DIETETICS The best brandy was originally produced in one of the richest wine districts of France (Departement de la Charente or Cognac district). The quality varies with the character of the grapes, the best grapes yielding the variety known as Fine or Grande Champagne. This is the only genuine liqueur brandy. The varieties known as Petite Champagne and Premiere Bois rank next to it. If sold pure, these constitute old Cognac, but a large amount of them is used for blending with inferior varieties. In a good year six or seven bottles of wine should yield one bottle of brandy. When first distilled the spirit is devoid of colour and of a fiery character. When kept in cask it takes up colour from the wood and gradually becomes mellower. Improvement goes on for a long time, so that the older the brandy the better. After twenty or forty years it contains a considerable proportion of volatile ethers and aldehydes, to which some of the most valuable properties of brandy are to be attributed. 1 While the above is the origin of genuine brandy, , it must be admitted that very little of the brandy sold in this country is so derived. The greater part of it is really concocted in the Cognac district from ' silent spirit ' coloured with burnt sugar and flavoured with cenanthine or various essences. Such a product is entirely different from genuine brandy, for it contains but little of those volatile ethers derived from wine which are so conspicuous in genuine Cognac, and to which, as we shall see, it owes most of the valuable results it is capable of producing in sickness. The production of genuine brandy by the distillation of Spanish wines has recently been begun at Jerez and elsewhere, and the' product is pronounced by competent authority to be fully equal, in regard to the amount of ethers present, to pure Cognac. 2 If this standard is maintained, Spanish brandy should have a great future. It is the possession of volatile ethers in large amount which mainly distinguishes brandy from whisky ; as regards alcoholic strength, the two are about equal. Rum. Rum is usually produced by the distillation of fermented molasses obtained in the manufacture of raw sugar ; the best varieties, how- 1 For the changes which take place in brandy by age, see a paper by Rocques (ref. in Analyst, 1897, p. 38) ; also ' Report of the Lancet Special Analytical Com- mission on Brandy ' (Supp. to the Lancet, 1902, ii. 1503). 2 See ' The Composition of Brandy,' by Sir Charles Cameron and Professor W. R. Smith, Journal of State Medicine, 1899, vii. 317. GIN 359 ever, are obtained by direct fermentation of the juice of the sugar, cane. The spirit contains bye-products of fermentation, which impart to rum its characteristic flavour. The chief of these is said to be ethyl butyrate, and a considerable proportion of the rum sold in this country is made from silent spirit flavoured with that substance. Rum owes its dark colour to burnt sugar. When kept for some time, it improves greatly in flavour by the development of ethers in which it is peculiarly rich. It usually goes into consumption at about the same alcoholic strength as whisky, or perhaps a little stronger. Gin. Gin (also known as Geneva — from geniewe, a juniper — Schiedam and Hollands) is obtained by fermenting a mash of rye and malt, and distilling and redistilling the product. Juniper-berries and a little salt, and sometimes also hops, are added in the final distillation, and the product is run off into underground cisterns lined with white tiles, where the spirit can be kept without colouring. The chief seat of the manufacture of genuine gin is at Schiedam in Holland. Much so-called gin, however, is fabricated elsewhere out of silent spirit flavoured with salt, juniper-berries, and turpentine. Gin is allowed to be sold with as low a proportion of alcohol as 35 under proof (37 per cent, alcohol by volume), but is usually im- ported at 14 to 15 under proof. It is thus one of the most dilute of spirituous drinks. Sweetened and diluted gin is sold under the name of Old Tom. Whilst varying somewhat in alcoholic strength, all the spirits we have been considering agree in containing very little solid matter — less, indeed, than 1 per cent., gin being the poorest in this respect. They have also a very low degree of acidity, rum standing highest, then brandy, with 1 grain per ounce (reckoned as tartaric acid), while whisky and gin have only about 0-2 grain per ounce. They are all practically free from sugar, for which reason the introduction of special whiskies for diabetics is quite unnecessary. The following table, taken from the Report of the Lancet Special Analytical Commission on Brandy, represents the com- parative composition of the different spirits in a convenient form : 360 FOOD AND DIETETICS Constituents. Grain Spirit. Beet Spirit. Jamaica Rum. Scotch Whisky. Gin. Typical 3-Star Brandy. Alcohol per litre by weight ,. ,, by volume Equal to proof spirit per cent. Extract per litre 932 p 6o 956-00 I67-55 Nil. 912-go 942 OO 165-09 Nil. 6l9'20 695-00 121 79 6-36 436-20 5I2 - 00 8977 I-I6 401'50 475-00 8326 052 410-50 485-00 84-96 670 Acidity (calculated as acetic acid Aldehydes (as ethylic aldehyde) Alcohol in ethers (not in total) Ethers (expressed as ethyl Higher alcohols 2-40 i'i5 Nil. 1-84 3-52 2-8o 4-80 10-92 Nil. 9 -20 17-60 6-95 122-40 15 41 2-08 161 -oo 308-00 62-58 33-60 I4-38 1-94 20-24 3872 12276 1920 4-72 0-13 4'6o 880 1325 37-5° 6-io 0-82 27-88 53 - 35 5848 Liqueurs and Bitters. This group of liquors may be regarded as consisting essentially of spirit sweetened with cane-sugar and flavoured with aromatic or other herbs or essences. It has been well said that they are chiefly the product of the alchemist and the monastery. The proportion of alcohol in them is high, varying from 33 to 50 per cent, or more by volume. The proportion of the- other ingredients is shown in the following analyses of some of the most prominent members of the group, taken from Konig : AU onoi. Extract. Cane- Various Ash. By vol. By weight. sugar. Extractives. Absinthe . . 5893 — 018 — 032 Benedictine 5200 385 3600 32 57 343 0-406 Creme de Menthe 48.00 365 2828 2763 065 0043 Anisette 42.00 307 3482 3444 038 0068 Curacoa . . 5500 425 2860 28-50 010 0040 Kummel 33 90 24 -8 3202 31-18 084 0058 Angostura 4970 — 5'85 416 1 69 0068 Chartreuse 43i8 — 36-11 3437 1-76 The following is a brief description of the origin and constituents of some of the better-known liqueurs and bitters r 1 Absinthe. — Made by macerating Alpine plants of the wormwood species with the root of anise and sweet-flag and marjoram leaves in 40 per cent, spirit. A glassful (30 c.c.) contains the following amounts of absolute alcohol : 1 For this description the author is largely indebted to Simmonds' ' Popular Beverages of Various Countries,' London, 1888. SPIRITS 3 61 Ordinary absinthe .. 14-3 c.c. I Fine 20*4 c.c. Demi-fine .. .. 15-0 „ | Suisse .. .. .. 24-2 ,, The essential oil of wormwood is a convulsive poison. Curafoa. — Made in Amsterdam from the rind of bitter oranges grown in the island of Curacoa. Kirsch. — Made from cherries in the Black Forest. Noyau. — Made from the stones of cherries, containing oil of bitter almonds. Maraschino. — Made by fermenting a small sour cherry (tnarasca) grown in Italy and Dalmatia. Both the cherries and the stones are crushed and 10 per cent, of honey added, and the whole fermented. The spirit is diluted, and kept for some months to mature. Kiimmel. — Consists of brandy flavoured with cumin and coriander. Vermouth. — Chiefly made in Turin from white wine flavoured and rendered bitter with Pontic wormwood and orange wine, and sweetened by the addition of 20 per cent, of sugar. Chartreuse. — Originally made at the chief Carthusian monastery, near Grenoble, in France, and also at Florence. It contains a large proportion of sugar, the flavour being derived from various oils con- tained in angelica, hyssop, nutmeg, peppermint, and other herbs. Benedictine is a very similar product, made at the Abbey of Fecamp. Angostura is now chiefly made at Trinidad, but formerly at Angos- tura, the chief flavouring ingredient being the bark of that name, though other species are also added. Ratafia is a name now applied in France to various liqueurs made from spirit, sugar, and aromatic herbs. It derived its name from the fact that it used to be drunk at the ratification of compacts and bargains. The action of spirits on digestion is practically identical with that of pure alcohol. They can only delay digestion in virtue of the alcohol which they contain, and then only in intoxicating doses. In moderate quantity their influence is probably favourable rather than otherwise, just as is that of alcohol itself. Their acidity is so slight that they have but a small effect on salivary digestion. Liqueurs taken at the end of a heavy meal may perhaps give a fillip to digestion, and counteract to some extent any retarding in- fluence of coffee taken at the same time, but the large quantity of sugar which they contain makes them irritating to an empty stomach and possible causes of acidity. In studying the general action of spirits on the body, one must 362 FOOD AND DIETETICS distinguish carefully between the action of the alcohol itself and that of the bye-products of fermentation which occur along with it. It would be a great mistake to regard spirits as simply mixtures of ailcohol and water in nearly equal proportion. 1 Their high alcoholic strength renders all forms of spirits valuable stimulants where the action of alcohol pure and simple is desired. For such a purpose whisky is as good as any other, and pot-still or malt whisky possesses no real advantages other than flavour over the patent-still or grain spirit. In cases of profound nervous and cardiac exhaustion, on the other hand, especially if delirium be present, one does not want merely an action upon the heart, but that stimulating influence upon the brain and vital centres which the volatile bye-products seem to be alone capable of exerting. Pot-still whisky, rum, and genuine brandy possess these bye-products, and especially those of an ethereal nature, in largest proportion, and therefore are much to be preferred in such a case. It is important, however, that these spirits should be old and well matured, for it is only then that they become really rich in ethereal bodies, and, of the three, genuine liqueur brandy is far the best. 2 In a case presenting signs of profound nervous and cardiac prostration the best liqueur brandy should alone be employed, no matter how much one has to pay for it. There can be no doubt that its free and timely administration has saved many lives. ' It is when our patient is far beyond the region of controversy, and life itself is " in the balance," that I find a sphere of marvellous usefulness for the best liqueur brandy, or, in lieu of it, very old cognac. Brandy, or even whisky, where the alcohol has been changed by age and original quality into vinous and ethereal spirit, is almost a pure stimulant, and hardly an intoxicant or narcotic at all. . . . Low forms of bronchitis and congestion of the lungs, the extreme exhaustion of some forms of influenza, the later stages of typhoid, cases of worn-out stomach from gastric catarrh, cases of breakdown from overwork, etc., all of them characterized by weak- ness of heart, failing circulation, inability to take food, loss of the power to sleep, and exhaustion, come into the category of suitable cases ' (Murray). 1 It is only right to mention that the bulk of the medical evidence given before the Royal Commission on Whisky was in favour of the view that the results obtained from whisky in the treatment of disease are due essentially to the ethylic alcohol which it contains. See also Charteris and Cathcart ('The Physiological Action of Whisky on the' Circulation '), Brit. Med. Journ. , 1907, i. 1174. 2 See Anstie, ' On the Uses of Wines in Health and Disease,' p. 44, and Murray, 'Liqueur Brandy' ('Rough Notes on Remedies'), third edition, p. 133. USES OF SPIRITS 363 Spirituous liquors are too highly alcoholic for ordinary dietetic use unless taken in great moderation and freely diluted. Two or three glasses of whisky or brandy contain as much alcohol as most people can safely consume in one day. If this limit be observed, however, and the spirit freely diluted, they may agree well, owing to their almost complete freedom from sugar or acids. It is of interest to inquire at this point what constitutes the differ- ence between a good and a bad spirit. Why, for instance, does a crude whisky produce headache, furred tongue, and derangement of digestion, while a well-matured spirit has no such effects ? and why does one produce sudden and almost maniacal intoxication while another does not ? Much as this question has been discussed, it must be confessed that no satisfactory reply to it is yet forthcoming. One may wade through the evidence given by experts before the Commission on British and Foreign Spirits, or that on Whisky, and find nothing but confusion and contradictory statements. The public have a general notion that the bad effects of immature spirits are due to the presence of fusel-oil. Let us inquire into this for a moment. We have seen that ' fusel-oil ' is really a mixture of alcohols of higher boiling-point than ethyl alcohol. The exact nature of these alcohols varies with the source of the distillate. In brandy and patent-still whisky propylic alcohol is the chief one present ; the fusel-oil of malt whisky and rum consists mostly of butylic and amylic alcohol. Now, experiments have certainly shown 1 that these higher alcohols have a much greater toxic action than ordinary ethyl alcohol. But even in a bad whisky there is not more than T J 5 per cent, of fusel-oil present (about a grain to the glassful), and by experiment it is known that at least 1 per cent, is required to pro- duce any marked effects. Further, the effects of fusel-oil have been put to direct tests in the human subject. King Chambers 2 says that he gave fusel-oil to various people in doses of from 1 to 10 drops, with the result of producing feverishness, furred tongue, throbbing of the temples, and headache ; but other observers failed to get these results. Allen, 3 for instance, swallowed for a month con- siderable quantities of whisky to which he had added as much as 2 per cent, of fusel - oil without experiencing any bad results. Mr. Samuel, F.C.S., stated before the Commission on Spirits that 1 See Dujardin Beaumetz, ' L'Hygiene Alimentaire ' ; Richet's ' Dictionary of Physiology,' article 'Alcohol' ; and Binz's 'Lectures on Pharmacology,' N.S. , l8 95. i- 347 ; a l so Baer, Archiv. f. Anat und Physiol , 1898 (Phys. Abth.), 283, and Jeffroy and Serveau, Archives de Med. Exper., 1897, i x - 681. 2 ' Manual of Diet in Health and Disease,' p. 78. s Journal of the Society of Chemical Industry, April 30, 1891. 364 FOOD AND DIETETICS he had consumed 4 ounces of brandy a day for four days containing ■j^- per cent, of fusel-oil, and found no bad effects from it. This quantity was equivalent to 24 ounces of ordinary brandy with -j^- per cent, of fusel-oil. Finally, Zuntz 1 stated that when a controversy about fusel-oil was raging some years ago he gave patients consider- able doses of it in capsule, and never observed any bad symptoms in the form of indigestion, headache, etc. When we add to these results the fact that it is by no means clearly proved that old whisky is poorer in fusel-oil than young, it must be admitted that one can no longer regard the traces of higher alcohols in spirits as being responsible for the bad effects which these liquors sometimes produce. One is consequently confined to the supposition that the offending material is to be found amongst the other bye-products of fermentation, probably aldehydes such as Furfurol, while the local irritating effects of immature spirits on the stomach may be due to some empyreumatic body, e.g., pyridine. 2 As regards the greater intoxicating effect of crude spirits, it must be pointed out that these may be due to the quantity and not to the quality of the liquor consumed, for spirits lose a considerable proportion of alcohol when stored in wood. Binz has made the ingenious suggestion that some of the volatile ethers, produced in old spirits by oxidation, act as correctives to the action of alcohol, much as atrophine does to morphia, but of this there is as yet no experi- mental proof. Malt Liquors. This group includes beer or ale, and porter or stout. There is some confusion in the use of these names, and they have not quite the same meaning in all parts of the country. In some places the term ' ale ' is applied to the brown beverages, while the black drinks are spoken of as ' beers.' It is better to regard the terms ' ale ' and ' beer ' as synonymous, and to apply them to the paler liquors, and to speak of the blacker drinks as stouts or porters. There is some reason, however, to believe that ale and beer were not originally identical, but that the former term was the earlier, ' beer ' being only employed subsequent to the introduction of hops. Beer may be defined as the product of the fermentation of malt and hops. We shall see later that much of the ' beer ' in common use has not, strictly speaking, quite this origin. 1 Deut, Med Wochensch., 1893, xix. 466. 2 For a full discussion of this subject see a paper (' Concerning Injurious Constituents in Whisky, and their Relation to Flavour'), by Lauder Brunton and Tunnicliffe, Lancet, 1902, i. 1591. ' MALT LIQUORS 365 Malt is obtained by moistening barley and allowing it to germinate in heaps at a moderate and regular temperature. During germination important changes take place : the ferment diastase appears in the grain and acts upon some of the starch, converting it into dextrin and malt-sugar, while part of the proteids, by the action of another ferment, is also converted into soluble forms. The * green malt ' so produced is next dried, and upon the exact temperature at which this is carried out the character of the beer largely depends, for the lower (within limits) the temperature employed, the more powerful is the action of the ferments contained in the grain, and the larger the amount of soluble substances produced. Low-dried malts produce pale beer; those dried at a highe temperature yield a darker product. When drying is complete, the malt is ground and made into a mash with water. Rather hard waters yield, for some reason, the best beer, the water of Burton-on-Trent being apparently specially well suited for the purpose, and, indeed, in most breweries the water is artificially made up to the standard of that locality. After mashing, the wort is strained off from the malt and boiled- for an hour or two with hops. Boiling stops any further action of the diastase, and extracts from the hops their soluble ingredients. Chief amongst these are tannic acid and certain resinous bodies of bitter taste. A substance called 'hopein,' the nature of which has not been fully investigated, but which seems to have properties re- sembling those of morphia, is also extracted. ' Lupulin,' which is the secretion of the glands of the hop, does not seem to be present in the finest varieties. The boiled wort is next pumped out and rapidly passed over coolers, and is then ready for the addition of the yeast. Great care is now taken to employ pure yeast, for many of the diseases of beer, such as the development in it of acetic acid, are due to contamination with ' wild ' yeasts. Scientific brewing has made great progress in this direction in recent years. The yeast is added to the wort in vats, and fermentation is then allowed to proceed. Here, again, much depends upon the temperature employed. In this country fermentation is usually conducted at rather high temperatures, with the result that most of the sugar is broken up and the resulting beer is rich in alcohol. In Germany low temperatures are employed, and more sugar and dextrin are left in the beer, but less alcohol is produced. Low-fermentation beers also contain more carbonic acid than most English beers, and are therefore better aerated. It is thus that lager-beer is produced. When fermentation is complete, the yeast, which has been earring 366 FOOD AND DIETETICS to the surface, is skimmed off, and the beer is allowed to stand in shallow tanks till most of the remaining yeast has settled to the bottom. It is then run off into casks. Here a secondary fermenta- tion occurs under the action of the small quantity of yeast still contained in the beer, but it is restrained to some extent by the addition to the cask of an extra quantity of hops. The longer this lasts, the greater is the amount of alcohol produced, and if strong beer is desired it must be left in the cask for some months. At the same time some volatile bodies seem to be developed which impart to such beer its full flavour, while the production of more carbonic acid under pressure leads to partial solution of that gas, and gives to the liquor a pleasant sharp taste. Just before bottling a solution of isinglass in acetic or tartaric acid (' finings ') is added to the cask, which soon settles down in the form of a precipitate, carrying with it any remaining yeast cells and other impurities. After bottling, the beer becomes brisker than it was in the cask, probably because no gas can now escape from it. Strong beer will keep well in bottle for eighteen months. The taste for strong, full-flavoured ales seems now to be passing away, and a weaker and milder beverage is more largely produced, which, from the rapidity with which it goes into consumption, is termed ' running ale '; carbonic acid is often added to it by artificial aeration, and in order to insure its keeping an antiseptic is frequently added, especially in hot weather. Sulphite of calcium is largely employed for the purpose. It falls down quickly in the form of sulphate and does no harm. Salicylic acid is also used, but as not more than £ ounce is usually added to a 36-gallon cask, it may be regarded as quite innocuous. It is apt, however, to affect the flavour of the beer to some extent. The names applied to different beers vary in different breweries, and many of the commercial brands are made by the judicious blending of beers produced in different ways. One can distinguish broadly between mild and bitter ales, the former containing relatively more malt and less hops than the latter, while in mild the malt is also dried at a higher temperature. Indian Pale Ale is so called because it was first produced for the Indian market. It is very thoroughly fermented, and contains, there- fore, but little sugar, and being highly hopped it has good keeping properties, for the hops act as an antiseptic. The ' palatefulness ' of ale depends partly on the actual amount of solid matter (sugar and dextrins) which it contains, and partly also on the nature of these bodies. The higher-priced ales usually VARIETIES OF ALE 367 contain more solid matter — i.e., have a higher ' gravity,' and are more hopped than the cheaper sorts. A good ordinary ' bitter ' has usually about 18 or 19 pounds of solids to the barrel, while ordinary mild ale has only 16 or 17 pounds. A really good bitter will have about 22 pounds, and Bass bitter as much as 23 pounds to the barrel. A barrel contains 36 gallons. In an ordinary public-house the varieties usually distinguished are ' four-ale ' (i.e., ^.d. per quart), which is the poorest ; ' six-ale ' (6d. per quart), which is a mixture of mild and bitter and comes next ; and after that ' bitter ' and « Burton,' the last being the strongest of all. The description of brewing given above applies only to ' pure ' beers — that is to say, to beverages brewed only from malt and hops. A very large proportion, however, of the beer in ordinary consump- tion has not this origin, some cheaper source of sugar than malt being employed. Amongst the substitutes so used are invert sugar, potato glucose, flaked maize and rice ; and the liquor produced from them is sometimes termed substitute beer. A large amount of evidence concerning the production of these beers and their effects upon health was given before a recent Parlia- mentary Commission, but it must be admitted that the results were not very definite or satisfactory. It would appear that it takes an expert to tell the origin of a beer from its flavour, and it was cer- tainly not clearly shown that the ' substitute ' beers are really in- jurious to health, while they can undoubtedly be produced more cheaply than the genuine article. 1 Porter or stout is made in the same way as beer, but the malt is first roasted in cylinders, much as coffee is. This has the effect of producing some caramel, to which the dark colour of these beverages is mainly due, and it must also, by killing the diastase, prevent the further production of dextrin and sugar in mashing. The propor- tion of solid matter in the liquor is often enhanced by the artificial addition of caramel or of invert sugar. German beers, as has been mentioned, are fermented at a lower temperature than those of this country, and contain more dextrines. Secondary fermentation takes place in them to a large extent, and 1 Since the above was written an epidemic of arsenical poisoning has occurred from the consumption of ' substitute ' beer prepared from impure glucose. Too much importance, however, must not be attached to such an accidental occur- rence in deciding the question of the relative wholesomeness of ' pure ' and ' substitute ' beers. The statement still holds good that provided the materials used in its manufacture are free from impurity ' substitute ' beer has not been shown to be injurious to health. 3§§ Pood and DtEfETics produces much carbonic acid gas. They are decidedly les§ alcoholic, and more nourishing than English beers. Composition of Malt Liquors. The most important constituents of these beverages are alcohol, dextrins, sugar, and a small amount of soluble nitrogenous matter (together these make up the ' extract '), and vegetable acids. The following table 1 gives the approximate composition of some of these beverages : Alcohol. Total Acidity Water. Percent. £.,„„„, Proteid. Sugar. Dextrins. as Lactic Ash. by vol. *- xtract - Acid. Bavarian winter beer .. .. 91-81 3-21 4-99 081 0-44 2-92 o-n6 0-20 Bava rian summer beer . . . . 9071 368 5-61 0-49 0-87 4-39 0-128 0-22 Munich Hofbrau — 370 5-87 Spatenbrau . . — 3-23 661 Pilsener.. .. 9115 3-46 4-97 037 — — o-i6 020 Munich Bockbier 8872 407 7-23 071 0-90 — 0-17 027 English ale and porter.. .. 89-1 489 603 0-53 0-84 — 0-31 0-31 Berlin white beer — 3-91 4-85 — — — — — Allsopp's Lager 89-49 5-40 — 040 2-04 3-34 o - i2 0-27 The following is an analysis of Burton pale ale by Chittenden and Mendel 2 : Alcohol . . . . 4 to 5-25 per cent, by vol. Extract . . . . 4-4 „ „ Ash 035 The composition of two good specimens of stout is thus given by the Lancet 3 : 'Oat Stout.' • Nourishing t Stout. ' Extract 6-3 per cent. 8-o per cent. 624 ,, 655 „ 50 .. 525 „ 090 „ °'45 .. 0-33 „ Alcohol by vol. „ by weight Acidity Ash Chittenden and Mendel's analysis of Guinness's Dublin Stout is as follows : Alcohol (by vol.) . . . . 5-5 per cent. Extract . . . . . . . . 5 -42 „ Ash .. 0-36 „ 1 From Leyden's ' Handbuch der Ernahrungs Therapie,' i. 105. 2 American Journal of the Medical Sciences, 1896, cxi. 177. E 1897, ii. 314 ; ibid., 1898, i. 1408. ACTION AND USES OF MALT LIQUORS 369 It has been calculated that the chief ingredients of a pint (20 ounces) of good average bottled beer are these : Alcohol 1 fluid ounce. Extract 1 to 2 ounces. Free acids 25 grains. Salts 13 „ Action and Uses of Malt Liquors. 1. Action on Digestion. — Malt liquors have but little retarding in- fluence on salivary digestion, and what action they do possess is entirely due to their acidity. Stout is twice as acid as beer, and hence has a greater retarding action on the digestion of starch by the saliva. 1 Sound beer, indeed, in some experiments, 2 seemed actually to increase rather than restrain the action of ptyalin, but sour beer has a decidedly retarding effect. 3 On the other hand, in the living body the bitterness of beer may bring about a more profuse flow of saliva, and so end by improving rather than impairing salivary digestion. In the stomach beer does not remain, if taken alone, any longer than water, for 200 c.c. are found to have completely left it in about one and a half hours. If taken with other food, it delays the chemical processes of digestion more than the mere amount of alcohol which it contains will explain. Some 4 have blamed the ' extract ' for this, others the salts ; 5 but the action is, in any case, not an important one, for even half a litre of beer (about a pint), when taken with a mixed meal, was found to produce but very little delay in the stomach. 6 It is probable, indeed, that a tumblerful of good, brisk beer may actually aid digestion by increasing appetite and calling out a more abundant secretion of gastric juice and more active movements of the stomach. Malt liquors seem sometimes to give rise to ' acidity ' in the stomach. This may, perhaps, be the result of acid fermentation of the liquor, especially if it has not been kept very long in the cask. Beer is found by some persons to have an unfavourable influence on the liver, producing a sort of dyspeptic sluggishness. The way in which it does this is not fully understood, nor whether it is to be attributed to the malt or some ingredient of the hops. It is for this reason, amongst others, that beer is not a good beverage for the 1 Chittenden and Mendel, op. cit. 2 Aitchison Robertson, Journal of Anatomy and Physiology , 1898, xxxii. 615. * Roberts, 'Digestion and Diet,' p. 119. * Simanowsky, Arch. f. Hygiene, 1886, iv. 1. 4 Buchner, Deut. Archiv. f. Klin. Med., 1881, xxix. 537. 6 Puchner, op. cit, 370 FOOD AND DIETETICS Sedentary unless in very moderate amount. Stout is popularly believed to be more ' digestible,' and perhaps rightly, but bottled stout is an admirable soporific. ' If it be desired to avoid nervous- ness,' says Hutchinson, ' and to get rid of insomnia, shun tea and coffee, and drink Guinness's stout. ... I scarcely ever met with a man who could withstand the soporific effects of bottled stout. It is far better than opium, and induces a more nearly natural sleep.' It is interesting in this connection to note that the residue of dried beer is found to have a sedative influence very much like that of morphia; this has been ascribed to 'hopein,' one of the soluble constituents of hops. 2. Influence as Foods. — The large quantity of carbohydrate matter in malt liquors renders them the most truly nourishing of alcoholic drinks. A pint of good ale contains as much carbohydrate as i£ ounces of bread. I found the following amount of solids in some common varieties : Grammes in 100 c.c. Pilsener Lager (Bremen) 27 Amsterdam Pilsener .. 4'i Allsopp's Light Dinner Ale 52 Bulldog Stout 66 Bottled Lager (Bfirgerbrau) 68 Nourishing Stout (Mountjoy Brewery) . . 9/2 According to these figures, an imperial pint of Allsopp contains 30 grammes of solid matter, and has in addition about 36 c.c. of alcohol. Together these will yield about 337 Calories of energy, and 2 pints will contain one-fifth of the total energy required daily. A glass of milk yields about 184 Calories, a similar glass of good bottled beer about 168. It does not follow from this, however, that beer is almost as good a source of energy as milk, for, as we have seen, alcohol is to be regarded as a food of only limited value. Five litres of good German beer with 5 per cent, of ' extract ' should yield 250 grammes of carbohydrate (1,025 Calories), which is half the total required daily, and in addition 100 to 150 grammes of alcohol, with a fuel value of 700 to 1,050 Calories. Malt liquors must be strictly forbidden in many forms of disease. The combined effects of their alcohol and carbohydrates render them specially prone to produce obesity, and they are also to be regarded as frequent predisposers to gout. In all cases of inflammation of the mucous membrane of the genito-urinary tract, also, they seem, for some reason, to have a peculiarly bad effect, and the recurrence of a gleet, for instance, can often be traced to their use. They are too rich in carbohydrates to be suitable for any but the mildest cases of MALT LIQUORS AND DIGESTION 371 diabetes. Special beers are prepared, however, which contain very little extract and no sugar, and these can be safely recommended in cases of obesity or diabetes. Conspicuous amongst these is Harvey's sugar-free ale. It must be remembered also that malt liquors are bulky drinks, and indulgence in them introduces a large amount of fluid into the circulation. The effort to expel this surplus fluid throws an extra strain on the 'heart, which may be very injurious if that organ is already damaged. In Bavaria a special form of hypertrophy of the heart (' beer-heart ') is not uncommonly produced in this way, even in otherwise healthy persons. 1 Some very good non-alcoholic beers are now manufactured, and may be conveniently mentioned here. Best known of these is Kcps Ale, which contains about 0*7 per cent, of solids and less than £ per cent, of alcohol. Other excellent preparations of the same class are Barrie's Bitter Beer, 2 the Banks Company's Ales, and the products of the Nonal Company. 3 These possess the tonic and digestive actions of beer without its stimulating effects, and are a decided advance upon most ' temperance ' beverages. 1 See Von Striimpell, 6sten Versamml. deut. Naturforscher und Arzte zu Nurnberg, p. 97, 1893. a G. and P. Barrie, Albert Street, Dundee, s 84, Lillie Road, Fulhanu 24^-2 [ 372 ] CHAPTER XXI ALCOHOLIC BEVERAGES {continued) : WINES 1 Wine may be defined as a beverage produced from the pure juice of the grape by fermentation. Some add to this definition the saving clause, 'or with such additions only as are believed to improve its durability.' The quality of the wine depends very much upon the variety of the grape, the soil upon which it is grown, the mode in which it is cultivated, and the climatic conditions of particular years. The juice is obtained by crushing the grapes, treading being the method usually employed in order to avoid squeezing the stalks and stones too much, and so extracting undesirable ingredients. The chief chemical constituents of the juice are sugar, albuminous matters and certain acids, of which the most abundant- are tartaric and tannic acids. The sugar is a mixture of grape-sugar, or dextrose, and fruit-sugar, or laevulose, in the proportion of about three parts of the former to one of the latter. The relative amount of albuminous matter and sugar in the juice has much . influence on the character of the wine produced. The yeast lives upon the albuminous matter, and splits up the sugar, with the formation of alcohol and other products. If there be but little sugar and much albuminous matter present, the yeast can go on growing until all the sugar is split up. The wine will then be ' dry ' and of an acid taste. Such a wine is hock. If, on the other hand, the sugar is out of all proportion to the albuminous substances in 1 In obtaining material for this chapter, the author has been much indebted to the following, among other, publications : Thudichum and Dupre, ' A Treatise on the Origin, Nature and Varieties of Wine,' London, 1872 ; Thudichum, ' A Treatise on Wines,' Bohn's Scientific Library, 1896 : in the preface references will be found to most other modern works on the subject ; Gautier, ' La Sophistication des Vins,' 1884 ; Mulder, ' On the Composition of Wines ' (edited by Bence Jones), 1857; Dupre, 'What is Wine?' (Popular Science R eview, 1868, vii. 354) ; Windisch, •Die Chemische Untersuchung und'Beurtheilung des Weines,' Berlin. 1896; Anstie, ' On the Uses of Wines in Health and Disease,' Macmillan and Co., London, 1877. References to other papers will be found in the text, PEkMEtfTATlOti 6F WltfS ^ the juice, a limit is set to the growth of the yeast, and some sugar will be left in the wine, and it will then taste sweet. Should, how- ever, the sugar and albuminous matter be present in more equal amount, the wine will retain some of both, and, though not sweet, will not have a distinctly acid flavour either, and will be of full ' body.' Such a wine is burgundy. It must be remembered, more- over, that no matter how much albuminous substance and sugar the juice may contain, the production of alcohol cannot go on in- definitely, for the accumulated alcohol ultimately ends by paralyzing the yeast. This takes place when the proportion of alcohol in the fermenting liquid has reached about 16 per cent, by volume. Hence it is that a ' natural ' wine can never contain more alcohol than this ; indeed, there is rarely so much sugar present in the juice as to allow of it's containing so much. 1 If a wine contains more than 1 6 per cent, of alcohol by volume, one may be quite sure that spirit has been added to it artificially ; that is to say, it has been ' fortified.' Sherry and port as sold in this country are always ' fortified ' wines ; claret and hock, on the other hand, are ' natural ' wines. The colour of red wines is due to a pigment contained in the skins of the grapes, which is turned red by the acids of the juice. As the skins are left in the vat in making such wines, the alcohol which is produced gradually dissolves out this pigment, and so the wine • acquires its red or purple tint. The colour of the white or brown wines is mainly due to the oxidation of tannic acid in the cask. The yeast which adheres to the skin of the grape, and which is responsible for the fermentation of wine, is different from the yeast which produces the fermentation of malt liquors or spirits. Further, we now know that the characteristic qualities of different wines are due, in some measure at least, to the fact that they are produced by different species of yeasts. Thus, the yeast concerned in producing hock is different from that which produces claret, and by growing a hock yeast on a claret ' must ' one gets a wine which is, as it were, a cross between claret and hock, and has some of the distinctive characters of both. Bacteriology has in recent years come to the aid of the wine-producer, and by producing pure cultures of the different yeasts will shortly, no doubt, make wine production a much more scientific and certain process than it has hitherto been, and we may perhaps look forward in the future to tasting varieties 1 In order to produce 16 per cent, of alcohol in the wine, there must be 34 per cent, of sugar in the juice, while the usual proportion of sugar in the juice of most grapes is only from 13 to 30 per cent. Since the above was written, however, some natural Australian wines have been found to contain as much as 19 per cent, of alcohol by volume (see Lancet, 1901, i. 802). m FOOD AND DIETETICS of wine hitherto quite unknown. I have already pointed out that the bacteriologist, by working on similar lines, has already done this for cheese. The exact details of the process of fermenting grape-juice in order to produce wine from it vary considerably in different countries and localities, and little would be gained by attempting to describe them in detail. As a rule, the first fermentation lasts for from two to six weeks, depending largely upon temperature, and the wine is left upon the lees till the spring, when it is siphoned off for storage. Prior to being placed in the cask, it is ' racked ' by the addition of isinglass or white of egg, much as beer is by ' finings,' in order to remove albuminous matters (which prevent the wine from keeping) and suspended impurities. When clear, it is again ' racked ' off from the deposit, and stored in casks in the cellar. In the cask many very important changes take place to the occur- rence of which the ultimate character of the wine is largely due. For one thing, the alcoholic strength of the wine rises. This is due to the fact that the water of the wine soaks into the wood more than the alcohol does, and is lost by evaporation, so that the wine becomes more concentrated. As the water so lost is replaced by the addition of more wine, the increase in the proportion of alcohol is rendered all the greater. In the cask, too, a partial oxidation of the tannic acid takes place. This causes the white wines to become darker in colour, but has just the reverse effect upon the red wines ; for the oxidized tannic acid unites with, and carries down, some of their pigment. The small quaiitity of yeast which always finds its way into the cask produces a slow secondary fermentation of the wine, which often lasts for years. As a result of this, some of the remaining sugar is converted into alcohol, and in this way also the alcoholic strength of the wine is increased. As the proportion of alcohol rises, some of the ingredients of the wine, such as tannic acid and bitartrate of potash, become less soluble, and fall down in the form of a deposit. During this time also some of the alcohol is oxidized into acetic acid, and the formation of compound ethers takes place. The maximum quantity of these, however, is usually reached in about five years, for the presence of water prevents the formation of ethers continuing till all available acids are used up. After bottling, the formation of ethers still goes on, possibly with the aid of micro-organisms, but the alcoholic strength of the wine does not increase. It is quite a mistake to suppose that wine which has been kept long in bottle is necessarily stronger than a younger CONSTITUENTS OF WINE 375 wine. The reverse is the truth ; for the alcohol seems actually to diminish after the wine has been bottled some years. It is also an error to suppose that wine goes on improving indefinitely. Like all other organic things, it is liable to decay by the slow processes of oxidation, and few wines really improve after thirty years ; many, indeed, such as clarets, are at their best long before this, and it is only a few of the stronger wines, such as sherry and madeira, which will stand keeping for fifty, or possibly even a hundred, years. ■ Must ' contains : Water. G«pe-sugar| Iot030percent Malic acid. Tartaric acid. Racemic acid. Albuminous substances. ' Vegetable mucus.' Essential oils. Extractives. Mineral substances. Tannic acid Colouring matters Fatty substances from the skins and kernels. Constituents of Wine. The following is a list of the principal constituents found in grape- juice, or ' must,' and in the wine produced from it (Dupr6) i 1 Wine contains : Water. Grape- S u g arj 0t06percent . Ethylic alcohol, 5 to 22 per cent. Propylic , , Butylic , , Amylic , , Other higher alcohols. Malic acid \ Tartaric acid | Racemic „ | Acetjf " ^3 to 08 per cent. Formic ,, Propionic , Butyric ,, Ethers of foregoing alcohols and acids. Glycerine. Aldehyde. Carbonic acid and ammonia. Trimethylamin. Oils produced by fermentation. Albuminous matter. ' Vegetable mucus." Colouring matter. Tannic acid. Essential oils. Extractives. Mineral matters, 015 to o-6 per cent. It will be realized from this what a very complex fluid wine is. 5 It is a profound mistake,' says Dujardin Beaumetz, ' to regard wine as a mere mixture of alcohol and water. It is a complete living entity, if I may so say, of which all the elements constitute an ensemble so complex and homogeneous that we cannot modify one or another without producing profound changes in the composition pf the wine itself. . . . Wine has its youth, its maturity and its old J 'What is Wine?' {Popular Science Review, 1868, vii. 354). 376 FOOD AND DIETETICS age. Some vintages, such as burgundy, have a short life, and become prematurely old; others, like claret, have a much longer life, and are even sent on a voyage to hasten their maturity. Wines, too, have their diseases — diseases which usually result from imperfect manufacture and bad fermentation, leaving in them impure products.' The amounts of the chief solid constituents in i litre of wine are roughly these (Gautier 1 ) : Water Glycerine . . Colouring matter Tartrates . . Total solids 718 to 935 parts 4 ■> 10 ., 06 ,, 15 ,, 1 .. 375 ., , 14 .. 9° .. Ordinary Rhine and French wines have about 2 per cent, of solids ; port has about 5 per cent. It would serve no good purpose, however, to give an analysis of wines in detail, for, after all, the information which chemistry can give us about wines is of limited value. It can tell us, it is true, a good deal about those ingredients which have most influence upon health, but it cannot tell much about those volatile compounds to which the most highly-prized qualities of wine, such as flavour and bouquet, are due, and for which one chiefly pays in buying wine when, indeed, one is not merely paying for the label on the bottle. I propose, therefore, to describe briefly the most important of the constituents which influence health, and afterwards to consider the chief characters of some of the commoner wines in detail. 1. Alcohols. — Wine contains several alcohols, ethyl alcohol, how- ever, being by far the most abundant. Amyl, propyl, butyl, and other higher alcohols are present in traces, being derived chiefly from fatty substances contained in the skins and stones of the grapes. A hundred volumes of a natural wine may contain anything from 6 to 12 grammes of ethyl alcohol. If there be less than this, the wine tastes flat ; if there be more, one may be almost quite certain that alcohol has been added artificially — i.e., that the wine has been ' fortified.' The advantage of fortifying wine is that it enables it to keep better, subsequent fermentation being restrained, and the pro- duction of acetic acid prevented. It is often necessary in the case of wines produced in very warm countries, where fermentation cannot safely be allowed to go on to its full limits, owing to the danger of the growth of ' wild ' yeasts and the production of acids. Fortified wines not unfrequently have as much as one-third of their volume of spirit added to them, and require to be kept for a long time in bottle, 1 ' La Sophistication des Vins,' 188^. ACIDS IN WINE 377 in order to re-acquire a true vinous character. Partial sterilization of the wine by the process of ' pasteurization ' is now often used to effect the same object as ' fortification.' 2. Acids. — The natural acids found in wine are tartaric, malic and tannic. Acetic, formic, succinic and other fatty acids are produced by fermentation along with carbonic acid. Tartaric and tannic acids are the most important. The former occurs combined with potassium in the form of bitartrate of potash or argol. As the proportion of alcohol in the wine rises, the bitartrate becomes less soluble, and ultimately much of it falls out in the form of a crust of ' tartar.' Hence it is that wines become less acid on keeping. The form of tannic acid met with in wine is probably not identical with that of oak-bark. It is chiefly derived from the skins and stalks, and is therefore more abundant in red wines. It diminishes by oxidation on keeping, and in the mature wine is not present in any large amount ; for even an astringent red wine has only about 2 grains in a 2-ounce glass, while an ordinary glass of claret (4 ounces) has not more than 1 to i\ grains, or about as much as is contained in a cup of tea. Acetic acid may be produced in wine by the growth in the ' must ' of a special organism (the Mycoderma aceti), which, if unchecked, would ultimately convert all the wine into vinegar. It flourishes especially in very warm countries, and' the necessity for preventing its growth is one of the reasons why the wines of such countries are so often fortified. Acetic acid can also be produced by direct oxidation of the alcohol of wine in the presence of albuminous matter, and this occurs to some extent in the cask, and also in bottle, if any air finds its way into the wine through the pores of the cork. In order to prevent this, the bottle should always be laid on its side, so that the cork is kept soaked in wine. In a sound wine the total acidity is not more than o - 3 to 0^7 per cent. ; above this limit the wine will taste sour. It must be noted, however, that mere taste is no true indication of the acidity of a wine, for the sourness is much concealed by the presence of sugar. As a matter of fact, many sweet wines are quite as acid 'as the so-called sour wines. Dupre found the following amount of acid (reckoned as tartaric) in one bottle of wine : Claret 65 to 77 grains Hock .. .. 57 ..70 ,, Sherry 54 ,, 61 ,, Port 49 ,, 62 ,, Marsala 39 ,, 46 ,, 378 FOOD AND DIETETICS A sample of '47 port analyzed by Luff 1 had an acidity of o*6 pet cent., equivalent to 6 grains of tartaric acid in every wineglassful. He calculates that three-fourths of the total acid in two bottles of such wine would require to enter the circulation at one time in order to neutralize the alkalinity of the blood. The volatile acids in wine (acetic, etc.) should not be present in a higher ratio than 1 to 3 of fixed acids (tartaric). If the propor- tion is higher than this, the wine is slightly ' turned ' — i.e., is on its way to become vinegar. Red wines usually contain rather more volatile acid than white. 3. Sugar. — The chief sugar found in wine is fruit-sugar, or lsevu- lose. A ' natural ' or fully-fermented wine should contain about £ per cent, of sugar ; if there is less than this the flavour is not pleasant. As a rule, therefore, natural wines are ' dry.' Sauterne is one of the few natural wines which is rather rich in sugar. ' Fortified ' wines in which fermentation has been checked by the addition of spirit contain 2 per cent, of sugar or more, while the sweet wines may have as much as 20 per cent. Dupre found the following amount of sugar in different samples of wine : Hocks > . ., i'4to 86 Clarets .. .. 11 ,, 18 Sherries .. 217 „ 421 Ports . . .. 121 ,, 519 Old marsala .. 388 „ 451 Sauterne .. 125 Champagne .. 500 , „ down to almost none. It will be evident from this that sugar can hardly ever be present in wine to a sufficient extent to be of influence as a food. Even a sweet wine with 4 per cent, of sugar will contain only about an ounce in a bottle, or pretty much the same quantity as a bottle of ordinary lemonade. As Anstie points out, it is hardly possible to take in more than J to \ ounce of sugar daily in the form of wine without at the same time consuming so much alcohol as would produce intoxication. 4. Ethers. — These are produced by the interaction of the alcohols and acids contained in the wine. They are very numerous as regards variety, as can readily be imagined when it is pointed out that a wine containing five different kinds of alcohol and five acids may contain twenty-five ethers. Their actual amount, however, is always very small. The highest proportion Dupre found was in a fifty-year-old madeira, and even then there was only 1 part of ether in every 300 of wine. 1 ' Gout : its Pathology and Treatment,' Cassell and Co., 1898, p. 145 et seq. ACIDS IN WINE 379 The ethers of wine may be divided into two classes : (i) volatile, (2) fixed. The former are produced by volatile acids, such as acetic ; the latter by the fixed acids, such as tartaric. The volatile ethers predominate in natural wines, while most fortified wines contain the fixed ethers in greater abundance. To this rule, however, sherry and madeira seem to be exceptions, for they are often rich in the volatile class. Acetic ether is usually the most abundant volatile ether met with ■ in wine, but old wines may contain traces of aceto-propylic, aceto- butylic, aceto-amylic, aceto-caproic, and aceto-caprylic ether as well. The ethers — and especially the volatile ones — are of importance as imparting to wine much of its ' bouquet,' and a rough estimate of their richness in any particular wine can be made by noting the distance at which the bouquet can be smelt. They also contribute in large measure to some of the most important therapeutic pro- perties of wine, as will be explained later. The substance oenanthine, or oenanthic ether, demands special mention. It is derived from a hypothetical fatty acid (oenanthic acid) contained in the stones, stalks, and skins of the grapes, and more especially, perhaps, in the waxy fat which gives to the grapes their bloom. This acid is not found by itself in wine, but only in the combined or ethereal form. There is not more than 1 part of it in every 40,000 of wine, but along with glycerine and succinic acid it is mainly responsible for the peculiar ' vinous ' smell and taste characteristic of all wines in common. 5. Extractives usually make up the bulk of the solid matter in all wines, except such as are rich in sugar. They consist chiefly of carbohydrates, such as pectins and gums. They contribute to the taste and ' body ' of the wine. 6. Glycerine is produced along with alcohol in the process of fermentation, and is always present in wine and in sufficient amount to affect the taste. It is usually said that it amounts to one- fourteenth of the volume of the alcohol ; but that is not quite accurate, for different yeasts seem to produce it in varying amount, so that no definite ratio between glycerine and alcohol can be laid down. Varieties of Wine. Perhaps the most important division of wines is into (1) natural and (2) fortified. The natural wines, as already explained, are those in which fermentation has been allowed to go to its full limit — that 380 FOOD AND DIETETICS is to say, until the process is arrested spontaneously either by exhaustion of all the sugar and albuminous matter in the grape- juice, or until sufficient alcohol has been produced to prevent the further growth of the yeast. The latter consummation is reached when the fermenting juice contains 12 per cent, of absolute alcohol by weight, and natural wines, as denned by law, must contain less than that amount. Fortified wines, on the other hand, are those in which the process of fermentation has been artificially arrested by the addition of alcohol 1 either as ' silent ' spirit, brandy, or some other concentrated form. Fermentation being thus arrested before all the sugar has been broken up, such wines are apt to be sweet, and are, of course, of comparatively high alcoholic strength. Natural wines, on the contrary, are usually poor both in alcohol and sugar. The natural wines also, containing as they do a little acetic acid produced by prolonged fermentation, are rich in volatile ethers even in their youth, while the fortified wines, though they may ultimately contain much ether, only arrive at such richness in their old age, and the fixed ethers, except in the case of sherry and madeira, preponderate over the volatile. The distinction between natural and fortified wines is of further importance for this reason, that, as we shall see later, the natural wines are alone suited for habitual consumption as articles of diet, the fortified wines being rather to be regarded ss medicinal agents. The principal natural wines are claret and hock, and the Hungarian, Italian, Australian, and Californian wines. The chief members of the ' fortified ' group are port, sherry, madeira, and marsala. Champagne and the Greek wines are also usually fortified. Claret (probably derived from clairet, a thin vin ordinaire) is produced in the district of Medoc, the seaport of which is Bordeaux. It is a pure natural wine containing 8 to 13 per cent, of alcohol by volume, very little sugar (about J per cent.), and a moderate amount of acids, acetic acid being always present to some extent. It contains also a high proportion of volatile ethers. The best growths, or ' crus,' are Chateau Margaux, Lafitte, and Latour. Haut Brion is a red wine produced in the neighbouring district of the Gironde, and resembles a burgundy rather than a medoc. Sauternes are white wines made in the same district, and usually contain a good deal of sugar', from the grapes being allowed to hang for a long time on the vines before they are picked. The famous 1 In the case of some fortified wines, however, e.g., sherry, the alcohol is added after fermentation is complete. VARIETIES OF WINE 381 Chateau Yquem is the finest of all the white wines so produced. Thudichum states that brandy is sometimes added to the natural wines of Bordeaux : not that it is required for their preservation, but simply in order to suit the English palate. Burgundy resembles claret, but is richer in extractive matter, and has therefore more ' body.' It is also of higher alcoholic strength. It is produced in the district of that name, the best part being that which stretches between Dijon and Chalon. The most esteemed varieties are Beaune and Chambertin. Beaujolais and Macon, though not really produced in Burgundy, are usually classed with those wines. Ordinary burgundy is made from black grapes, but Chablis is a white burgundy produced from white grapes grown in the same district. Hocks derive their name from Hochheimer, on the right bank of the Maine. With the exception of that produced at Assmanns- hausen, they are all pale wines. They have about the same alcoholic strength as claret, and contain hardly any sugar, for which reason they are apt to seem rather acid. Their acidity, however, is not much higher than that of claret (about \ per cent.), and they contain almost no acetic acid. They have the advantage of possessing a fine bouquet and extraordinary keeping qualities. The choicest varieties are those of Johannisberg, Steinberg, Marcobrun, Riides- heimer, Rothenberg, and Hochheimer. Hungarian wines are both red and white, and rank with claret and hock as the finest natural wines the world produces. Their alcoholic strength is about the same as that of the other two, but they are rather more acid. They resemble hock in being almost free from sugar. The finest variety, Tokay, is produced from grapes which have been allowed to dry on the stalks before being picked. It is a sweet wine of low alcoholic strength, and should have been kept very long in bottle. The special Imperial Tokay is one of the choicest wines known, but is never sold in trade. Some of the commoner dry Hungarian wines, both red and white, make excellent table beverages. They have rather more body than the corresponding wines of France, and a moderate degree of astringency. Italian wines, both white and red, all belong to the ' natural ' class. As a rule, they are of low alcoholic strength, but rather more acid and astringent than a light Bordeaux wine. Their acidity is rather high. The following analyses from the Lancet 1 represent the composition of some of the varieties more commonly sold in this country : 1 1899, i. 241. 38a FOOD AND DIETETICS Alcohol by weight „ ,, volume Tartaric acid Acetic ,, Sugar Capri (White). 11-62 *4'37 052 031 076 Falerno (White). 864 1073 066 013 Oil Chianti (Red). 936 ii-6i o 60 018 017 Barolo (Red). 10-85 1343 0-45 025 0-18 Egidio Vitali (Sparkling White). IC08 1249 079 026 3 '67 Valtellina (Red). 936 II-6l 0-41 029 013 Californian wines, from a merely chemical point of view, compare very favourably with the corresponding wines of Europe, though they are undoubtedly not yet equal to the latter in the more aesthetic qualities. For natural wines, they contain rather a high proportion of alcohol, but relatively little glycerine. In the white varieties the extract, total acidity and ash are generally lower than in the corre- sponding European wines, while in the red sorts these ingredients are relatively higher than in the old-world wines. A careful inves- tigation of them has been made by Krug, 1 who concludes as follows : • On the whole, it is evident that the Californian dry wines are fully equal to the European wines, and the red wines are in every respect superior to the young French clarets. The sweet wines are to be unconditionally preferred to the European Southern wines, containing the same amount of alcohol and extract, and not being plastered." Their chemical equality with European wines is also confirmed by the Lancet, 2 from which the following analyses are taken : Alcohol by weight „ „ volume Extract Ash Total acids Californian Sauterne. Per cent. A Californian Hock. Per cent. 1031 1000 1277 231 016 069 1240 1 -go 020 067 The Australian wines resemble, rather closely those of California, They are full-bodied natural wines, containing rather more alcohol than most clarets. They are chemically pure, and in recent years have improved very much in the finer characteristics of good wine, as the result of greater care in the cultivation of the grape. The term sherry is applied to all the white wines of Spain, being derived from the town of Jerez, which may be regarded as the capital of the sherry-producing district. As drunk in this country, they are all fortified wines, containing from 15 to 22 per cent, of alcohol by weight. A ' natural ' sherry is quite a possible product, but is never imported into this country on account of its being 1 Journ. ofAmer. Chem. Soc, 1894, xvi. 597. 2 1894, ii. 30. CHARACTERS OF DIFFERENT WINES 383 deficient in ' keeping ' qualities. Sherries are also all ' plastered ' wines ; that is to say, sulphate of lime is sprinkled on the grapes after they are first trodden, in the proportion usually of i\ pounds to every ton. The practice of plastering is one of great antiquity,' and was mentioned long ago by Pliny. It was first adopted, no doubt, empirically, and the advantages of it are still far from being fully understood, although all experienced sherry-growers are of opinion that without its aid the production of a wine having the special characteristics of sherry is impossible. It may be that it acts as a preservative against the ' viscosity fungus,' which is so much commoner in Southern than Northern wines (Thudichum). The chief chemical effect of plastering is to decompose the bi- tartrate of potash in the ' must ' with the production of insoluble tartrate of lime, sulphate of potash, and tartaric acid, according to the following equation : 2KHC 4 H 4 6 + CaS0 4 =K 2 S0 4 + CaC 4 Hj0 6 + H 2 C 4 H 4 O e . The phosphates are also thrown down. As the tartrate of calcium falls out, it clarifies the wine, carrying down with it albuminous matters and suspended impurities. The tartaric acid produced renders the wine redder, and increases its free acidity, so facilitating the production of ethers later on. There is introduced into the wine as the result of plastering o - 3 gramme of sulphate of calcium per litre, and i - 2 grammes of sulphate of potash, much of it, probably, in the acid form. The sulphate of potash may cause sherry to be slightly laxative to some persons if freely drunk, and renders it also somewhat bitter, but it cannot be said to have any other bad effects. It has been said that it may be productive of cirrhosis, but of thh there is no sufficient evidence, and, indeed, the employes in the Spanish bodegas are stated to drink as much as 10J pints of light sherry daily, without suffering from any injurious effects. The amount of sugar in sherry varies from practically nil in the driest sorts up to 4 per cent, in a very raisiny wine. The acidity is lower than that of the natural wines already considered. Sherry develops in its old age a very large proportion of volatile ethers — more, probably, than any other alcoholic liquor, except a genuine cognac. To this property much of its value as a stimulant in disease is to be attributed. Broadly speaking, there are two classes of sherries : 3S4 FOOD AND DIETETICS. 1. ' Fino,' a light, pale, delicate wine of Amontillado 1 or Manzanilla 2 type. 2. ' Oloroso,' a sweeter, full-bodied, brown wine, between these is the class known as ' Palo Cortado.' The following is an analysis of examples of these : 8 Solids Sugar Potassium bitartrate Tartaric acid Acetic „ Ash Sulphate of potash Alcohol by weight , , , , volume Total ethers Amontillado. Per cent. 220 0215 008 • 034 , 012 . 055 . 0-52 . 1482 . 1825 006 Oloroso. Per cent. 545 I 03 026 052 020 086 076 1885 23-10 021 Intermediate Medium. Per cent. 287 065 013 0-41 o - io 070 065 i5'67 1928 0075 Pure sherry may be regarded as a genuine grape product, for the substances added to it in manufacture are also derived from grapes. Thus, ' grape liquor ' is used for sweetening, and the same, slightly caramelized, for colouring. The spirit added in fortification is also obtained by distilling fermented grape-juice. Port is the wine produced in the district of the Upper Douro, and takes its name from the town of Oporto. The whole of the wine that reaches this country is fortified, containing from 15 to 20 per cent, of alcohol by weight. One of the chief peculiarities of port is the large amount of ' extract ' it contains, which gives it a full body. Its acidity is not great, less, indeed, than that of hock, but it contains relatively more acetic than tartaric acid, for the latter is insoluble in the large amount of alcohol which port holds. It possesses a good deal of tannic acid, the stalks not being removed before fermentation, but this diminishes with age, though when young it is very rough and astringent. It is sweeter than sherry, containing from 2 to 6 per cent, of sugar, for it is fortified before fermentation is complete, not after it, as sherry is. Old port contains a large proportion of ethers, but, unlike sherry, the fixed ethers predominate over the volatile. When mellowed it has an excellent flavour and bouquet, and retains only a moderate amount of fruitiness. Madeira is derived from the island of that name. For a long time the ravages of the phylloxera stopped the production of the wine, but in recent years the industry has begun to revive. The wine resembles sherry in its general characteristics and in the high pro- 1 Amontillado = a la Mantilla (a town near Cordova). s From Manzanilla, a town near Jerez. 8 Lancet, 1898, ii. 1135 (Report of Commission on Sherry, from which many of the statements in the above paragraphs are taken). MARSALA AND CHAMPAGNE 385 % portion of volatile ethers which it contains. It is a fortified wine, containing from 17 to 20 per cent, of alcohol by weight. Marsala is a Sicilian wine also resembling sherry, but sweeter and containing a much lower proportion of volatile ethers. It is only slightly acid. Greek wines may be either natural or fortified, but usually contain only 8 to 14 per cent, of alcohol by weight. They are rich in volatile acids, and are peculiar, also, in containing some aldehyde. They are often plastered. Their chief defects are due to imperfec- tions in the methods of manufacture. Champagne is the wine produced in the Champagne district of France, the best varieties being obtained from the prefectures of Rheims and Epernay. It is produced, curiously enough, chiefly from black grapes. These are squeezed in a very powerful press, and the first pressings used to produce the finest wines. The character of the vintage in different years has also a very marked effect on the quality. The expressed juice, or ' must,' is allowed to stand for twelve hours in order to let all suspended matters fall out, and is then drawn off into casks to undergo the first fermentation. At this stage the different growths, or ' cms,' are blended to form the special ' cuvees,' the finest of which are only produced from the best grapes. The young wine is then bottled and left for two years, to undergo the secondary fermentation. The maintenance of a constant temperature is very important at this stage, and is attained . at 'Chalons, Epernay, and Rheims, by storing the bottles in large cellars excavated from chalk cliffs. During this fermentation a large amount of carbonic acid gas is produced, and as the percentage of alcohol rises a considerable deposit falls down into the neck of the inclined bottle. This is fixed to the cork by freezing, and removed with the latter in the process of ' d6gorgement.' The wine is still of a sour, harsh, or ' brut ' character, and is made drinkable by ' dosage.' This consists in adding to it a solution of cane-sugar 1 dissolved in old champagne and good cognac. Upon the amount of dosage the sweetness or dryness of the wine depends. In this country we like champagne dry, and therefore only 2 to 4 per cent, of liqueur is added to the wine exported to England. For Russia, where a sweet wine is preferred, as much as 14, or even 16, per cent, of liqueur is used. The wines exported to the United States, Belgium and Germany receive an intermediate degree of treatment. There can be no doubt that the taste for a dry champagne is rewarded by 1 The cane-sugar is gradually changed into invert sugar after its addition to the wine. 2 5 386 FOOD AND DIETETICS getting a purer wine, for heavy liqueuring covers many defects. Hence the dry wines are really the finest. It must be remembered, however, that unless 8 per cent, of liqueur has been added the quality of the wine will not be found to improve after longer than twenty years. Champagne should, strictly speaking, be a natural wine, con- taining from 9 to 12 per cent, of alcohol by weight, but in recent years a taste for a stronger wine has grown up, and champagne as drunk in England is now mostly a brandied liquid (Thudichum). The amount of sugar varies from nil up to 14 per cent., depending on the dosage. The acidity is about 0-5 to o*6 per cent. — i.e., that of an average claret. A dry champagne contains about 2 per cent, of solid matter. A bottle of good champagne will contain about five volumes of carbonic acid gas. Four-fifths of this, however, is given off whenever the cork is drawn. The following table from Dupre's analyses may be of use for the purpose of comparing the chemical composition of some of the wines just described. It must be remembered, however, that mere chemical analysis is only of limited use in judging of the quality of a wine : Wine. Grammes Absolute Alcohol. Free Fixed Acid. Free Volatile Acid. Total Acid. Sugar. Dry Resi- due. Ash. Total Alcohol in Ethers. Hock (three samples) Claret (three 973 0'399 0088 0506 0062 I 92 0-17 0042 samples) 968 0390 0167 0'599 0243 2124 021 0038 Hungar i a n wine (three samples) 1016 0454 0192 0694 0077 igo6 018 0046 Greek wine (three samples) Sherry (three samples) Madeira (two 1235 1780 0342 0286 0215 0'l6l 0611 0-487 0225 3015 2507 506 030 0-50 0048 0061 samples) Port (three 1782 0373 0247 0680 1-85 444 0'37 0096 samples) Marsala (two 1811 0309 009 0-434 z'54 534 023 0053 samples) 168 0-206 012 0361 35° 536 026 0049 The table gives weights of different ingredients in 100 c.c. To get grains per bottle multiply by 120. COMPARATIVE COMPOSITION OF WINE 387 The following more recent analyses 1 may also be given : THE COMPARATIVE COMPOSITION OF DIFFERENT VARIETIES OF WINE. Wine. Alcohol. Extract. Acid. Sugar. Volume Grammes Grammes Grammes A. French Clarets : Per Cent. per Litre. per Litre. per Litre. Ch. Margaux 1268 2535 2-92 — Ch. Haute Lafite I248 27IO 3 28 — Bordeaux 10-70 27-24 3-48 — Medoc 10-25 23 - 39 3-i6 — Ch. Margaux ii-6o 2999 3 '3° — Ch. Larose .. 1001 24-09 3-28 1-08 Ch. Brane-Cantenac n-68 2344 302 — Ch. d'Issan 9-91 20 80 2-76 0-92 Sweet Sauternes n 68 36-12 3'97 140 Dry Sauternes 12-78 29-87 4-06 3-0 "Haut Graves 12-00 28-34 456 2-7 Graves 12-27 34 -I ° 4-99 40 B. Moselles : Moselle (1) 991 20-07 4'25 — Schwarzberger 1 1 -14 21 60 4-07 — Moselle A. . . iq-66 20-26 4-23 — Moselle '93 . . 11-41 22-28 4-5i — Moselle W. . . 9-23 18-31 363 i'35 Brauneberger 11-67 20 99 3-63 l'5l C. Hocks : Hock 1 1 1 '41 1906 298 — ,,2 9 23 2584 3-49 — .. 3 974 23-52 2-80 — .. 4 1089 5977 630 30-00 .. 5 976 2236 4-02 i'5i D. Champagnes : 1370 3570 4-02 19-2 ,, 2 13-90 35-II 4-21 18-4 3 13-48 35 - 20 4-12 156 4 10 -6l 71-16 4-96 55 'o E. Australian : Australian, 1 14-20 29-65 2-96 — ,, 2 16-19 36-68 298 284 3 13 '39 2915 4 - °5 1-08 .. 4 13-16 25'°4 33o 0-92 5 1448 37-40 4 -I 7 2"57 6 13 "25 2846 3'97 1-63 7 15-46 88-27 4-21 50-00 8 I5'36 3024 4-02 2'57 F. Spanish, 1 1360 33-66 3-63 8-08 G. Italian, 1 1079 22-90 363 I'OO Cider and Perry, derived from the apple and pear respectively, may be conveniently considered here, for they are really to be 1 Report of the Hospital's Commission on- Light Wines (The Hospital, rgo7, xlii. 285). 25—2 388 FOOD AND DIETETICS regarded as wines ; cider, indeed, when first made in England in the thirteenth century was always called ' wine.' The finest English cider is made in Devon, Hereford and Somerset. The mid-season fruit, which ripens in October, is best for the purpose. It is gathered and allowed to mellow under cover for a fortnight, and is then ground to a pulp, the kernels being sometimes left out. The pulp is left in vats for thirty hours, and is then pressed, and ioo gallons of the liquor run into a clean vat and left for some days till it clears. It is then racked, clarified with charcoal and strained through bags, and the clear, bright liquid run into ioo-gallon casks and bunged down. 1 Perry is made in a very similar way. If a ' sparkling ' beverage is desired, fermentation is allowed to go on in bottle. The composition cf these beverages seems to vary within rather wide limits. They are only mildly alcoholic, having 3 to 8 per cent, by volume, or much the same proportion as beer. Sugar amounts to 0-2 to o-6 per cent. They are moderately acid (o-i to o - 6 per cent.), the chief acid present being malic. The more acid varieties (o-6 per cent.) will have an acidity equal to about 22 grains of tartaric acid per tumblerful. A sample of genuine Devonshire home-made cider which I examined had the following composition : Alcohol (by volume) 60 per cent. Solids .. .. .. .. .. i'j ,, Total acidity .. .. .. .. 066 ,, Volatile acidity .. .. .. .. 0089 „ The following analyses are from the Lancet : i Cider. Champagne Perry. Alcohol by weight 270 145 ,, „ volume .. .. 340 180 Solids 816 no Ash . . . . . . . . . . 032 035 French and American imported ciders are thinner and weaker than the home-made article. Bottled cider has less alcohol (3 to 4 per cent.) and more sugar (2 J to 6 per cent.) than draught. 3 - Medicated wines are concoctions, the basis of which is port or sherry, to which has been added extract of beef, extract of malt, peptone, pepsin, coca leaves, cocaine, cinchona, iron, or some other dietetic or medicinal substance. A ' beef and malt wine ' may usually be regarded as containing about i\ ounces of extract of meat 1 Radcliffe Cooke, Journ. of the Soc. of Arts, 1895, xliii. 396. 2 October 1, 1892. 8 Felix Aury, ' Le Cidre et le Poire,' These de Paris, 1894. MEDICATED WINES 389 and 2 ounces of malt extract in a pint of * detannated ' port or sherry. 1 For the medicinal wines there is no definite formula. Of the ' coca ' wines, some are made from coca leaves, others from liquid extract of coca, and some from hydrochlorate of cocaine. The following table 2 shows the proportions of the chief ingredients present in some of these wines, the composition of the ordinary standard wines being given for comparison : Meat Extract Wine. Alcohol by Volume. Sugar by Weight. by Weight, . corresponding to Nitrogen Found. Pure Alcohol in a Wine- glassful. Per Cent. Per Cent. Per Cent. Fluid Drachms. Claret 9 0-25 — I* Hock IO Trace ■ — *4 Champagne (dry) 10 to 15 Trace to 2 — Ij to 2 Sherry (dry) (brown) 18 23 i-o f — 3t0 3j Port zo 2 to 6 — 3i Bovril Wine 2015 102 °'5 3i Lemco Wine 1 7 '26 128 o-6 2j Wincarnis 196 18-2 12 3 Glendenning's 20 -8 106 04 34 Bendle's Meat Port Nutrient 3 20 '3 8-0 2 '5 3i 192 11-5 3 '4 3 Vin Regno 16-05 7'4 ° - 3 2* The use of these wines can on no grounds be recommended. In the first place, they are not worth the price charged for them, for it is far cheaper and also better for an invalid to get beef or malt extract separately and take along with them, if need be, a definite quantity of sound wine of known antecedents. 4 In the second place, it is open to grave question whether the ferment of malt (diastase) is not much impaired by the action of the alcohol to which it is exposed when dissolved in a fortified wine, such as port or sherry. The medicated wines are open to the same objection to an even greater extent. The use of such liquors by an invalid on his own responsibility, or even by prescription, exposes him to great danger of becoming by degrees the unconscious victim of alcoholism, and, in the case of the coca wines, of the cocaine habit as well. On every ground their manufacture and sale should be strongly depre- cated by the medical profession. (See also p. 565, footnote.) 1 The quantity of bouillon represented by a wineglassful of such a wine varies from about 4 tablespoonfuls to ij teaspoonfuls {Brit. Med.Journ. , 1909, i. 795). 2 Brit. Med. Journ.,- 1909, i. 795. 3 Meat Port Nutrient is peculiar in containing about ij to 3 per cent, of uncoagulated proteid of beef-juice (Lancet, 1908, ii. 242). * See also Coley, Brit. Med. Journ., 1898, ii. 715. 390 FOOD AND DIETETICS Non-Alcoholic Grape Wines are now made which consist of pure grape juice preserved by pasteurization (' Mostelle,' ' Vindevie,' 'Salvator Brand,' etc.). Suitably diluted, they form pleasant and refreshing drinks, useful for quenching thirst in fever and possessed of slight laxative and diuretic properties. 1 Action and Uses of Wines. Influence on Digestion. — Wines have a much more powerful inhibitory effect on salivary digestion than mixtures of alcohol and water of similar strength. Roberts, 2 for example, found that if even i per cent, of sherry or hock were present in the digesting mixture, the conversion of starch was almost brought to a standstill. This effect of wines is entirely due to their acidity. The experiments of Aitchison Robertson 3 showed that a claret of 075 per cent, acidity had a markedly retarding effect on salivary digestion, while the influence of a sherry of 0-54 per cent, and a port of 0*42 per cent, was very much less. Chittenden and Mendel confirmed these results. The inhibitory effect of wines is lost when their acidity is neutralized. Hence, it is an obvious advantage, from a digestive point of view, to mix the more acid wines with an alkaline aerated water. On gastric digestion, also, wines exert a retarding effect out of all proportion to the amount of alcohol they contain. The cause of this is not clear. According to some writers, it depends upon their solid ingredients. Roberts attributes it, in part at least, to some of the volatile constituents. Sherry and port seem to have a more powerful effect than claret or hock. Half a pint of sherry in 2 pounds weight of stomach contents is sufficient to produce a very pronounced degree of inhibition, and yet this is a not infrequent allowance. A pint of claret or hock is also enough to produce distinct effects. Effervescing wines, on the other hand, such as champagne, are much more feeble in their results, probably because the gas which escapes from them churns up the contents of the stomach mechanically. ' The effect of wines on pancreatic digestion is akin to their action in the mouth, and may be entirely explained by their acid qualities ' (Chittenden). It must be remembered that the above remarks apply only to the effects of wines upon the chemical processes of digestion. 4 As in the case of alcohol, it by no means follows that the net result of taking wine with meals is unfavourable ; for, by the increase of appetite 1 For analyses see the Lancet, 1903, ii. 761. They are supplied by Rein- heimer and Co., Surbiton, Surrey; J. Rabourdin, 1, East India Avenue, E.C. ; Schweppes, Ltd. , and others. 3 'Digestion and Diet,' p. 117. 8 Journ. of Anat, and Physiolog., 1898, xxxii. 615. 4 The conclusion drawn from experiments made by a Special Commission on light wines (The Hospital, 1907, xlii. 285) is that such wines, in quantities of from 8 to 10 ounces, are ' in no sense inimical to digestion.' ACTION OF WINES IN HEALTH 391 and gastric secretion which they induce, they may, in moderate quantity at least, not only neutralize any inhibition of the merely chemical processes which they exert, but actually render digestion quicker and easier than it otherwise would be. This, indeed, is one of the most useful actions of wines both in health and disease. General Action of Wines in Health. — ' The conventional value of wine is determined less by its principal ingredients than by the prominence of the specific character termed bouquet and the absence of certain faults. Dietetically, most wines, are of equal value pro- vided they are the products of a favourable season, pure and free from the faults produced by fungi ' (Thudichum). ' I have purposely made no attempt to answer the question so frequently and so uselessly put, " Why is one kind of wine better than another ?" Every constituent helps to promote excellence : alcoholic content, bouquet, and every non-volatile ingredient. One " wine is liked on account of its aroma, another on account of its strength, a third simply because of its flavour ' (Mulder). These two quotations contain the gist of most that can be said as to the action of different wines on the human body. Nevertheless, they do not embrace quite the whole truth. We may admit that, for the purposes of dietetics, most sound wines are equally good as long as their alcoholic strength is the same, and that the aesthetic qualities determine their market much more than their hygienic value ; but it must be remembered that a wine may contain ingredients which elude chemical analysis, but which are yet not without influence upon health, for, as has been truly said, ' the human brain and the human stomach are the only analysts which never makes mistakes.' The subject is further complicated by the fact that different constitutions react very differently to the same wine, a fact which must be within the experience of everyone. To some extent this may be explained by difference of habits, the sedentary man, for example, requiring to be much more sparing in his use of certain wines than his fellow of more active pursuits ; but this does not account for all the facts, and much must be put down to what, for want of a better name, one can merely describe as idiosyncrasy. In endeavouring to get further light on the subject, we shall do best to consider the tvffects of the principal constituents of wines on the body individually, and afterwards attempt to deduce from the results of that study some general rules for our guidance in recom- mending wines in health and disease. Alcohol. — As a general rule, the stimulating action of any wine 392 FOOD AND DIETETICS depends chiefly upon the amount of alcohol which it contains. Now, the natural wines only contain about half as much alcohol as the strong or fortified wines, so that two bottles of good claret or hock are about equal, as far as alcohol is concerned, to one bottle of port or sherry. Roughly speaking, then, the stimulating action of a fortified wine may be regarded as twice as great as that of a natural wine. This, however, is not necessarily quite true in any given case. Wines cannot be regarded as mere mixtures of alcohol and water in different proportions. For one thing, the mere fact of dilution is of importance. The more dilute the alcohol is, the more slowly it will be absorbed, and the less the chance of a large quantity of it reach- ing the tissues at one moment. The ethers and other volatile con- stituents, too, have a certain modifying influence upon some of the actions of alcohol, and a wine which is rich in these elements may be expected to have a different effect from another which is devoid of them, even although the two are cf equal alcoholic potency. Notwithstanding this, and when all due weight has been given to such modifying factors, one is pretty safe in concluding that it is only the weaker, i.e., natural, wines which are adapted for habitual use as accessories of the diet. We have further learnt that from i to 2 fluid ounces of alcohol is about the amount which can be safely taken in one day. Now, 2 fluid ounces of alcohol are contained in one bottle of good claret or hock, and therefore we may conclude that half a bottle daily of such wines is a safe allowance for a sedentary individual, and a whole bottle is enough for a man of more active life. The fortified wines, on the other hand, should be reserved for special occasions, or should only be used as medicines under medical advice. Acids. — We have seen that acids are an indispensable ingredient of all wines, and that they are chiefly present in the form of bitartrate of potash, but that some wines contain a certain propor- tion of volatile acids, such as acetic, in addition. To the healthy man the amount of acid present in any reasonably sound wine may be regarded as harmless, but it is generally believed that wines with a high degree of acidity may be injurious to some constitutions, and especially to the gouty and the rheumatic. It is doubtful whether this proposition can be maintained in such an absolute form. One must remember that the organic acids and their salts contained in wine are converted in the body into alkaline compounds, and are excreted as such. Certainly bitartrate of potash increases very appreciably the alkalinity of the urine. It is difficult to see, there- ACTION OF ACIDS 393 fore, how its presence in wine can be other than beneficial, as far as gravel, at least, is concerned. As a matter of fact, Liebig long ago pointed out that the free use of hock (a rather acid wine) tended to prevent the precipitation of uric acid in the urine. The same is true of cider. Those who drink largely of it are not troubled with gravel; indeed, they are stated to enjoy a special immunity from that disease, for it not only renders the urine less acid, but increases its volume, so much so, indeed, that in Normandy the young and inexperienced practitioner is constantly diagnosing an imaginary diabetes. It may be objected that, although this may all be true as regards the deposit of uric acid in the urinary passages, yet the acidity of wines may render them harmful in the tissues before the oxidation of their organic acids into alkaline forms has had time to take place. Even this, however, is very far from being proved, and Luff has shown 1 that, as a matter of fact, the most acid wines are not those which are most generally credited with being producers of gout. The supposed connection, indeed, between variations in the alkalinity of the blood and the occurrence of gout has probably been exagger- ated, and demands much further investigation. The action of the tannin in wine must be sharply distinguished from that of its other organic acids. A rough or astringent and an acid wine are by no means the same thing, though there can be little doubt that the former is often mistaken for the latter. The red wines, as a class, are richer in tannin than the white, and port, especially when young, is one of the richest of all. Burgundy, on the other hand, does not seem to contain a large amount of this constituent. Owing to this property, red wines may be useful in diarrhoea and harmful to the constipated, but it is a mistake to suppose that the mere presence of roughness or astringency (i.e., of tannin) in a wine confers upon it any special strengthening qualities. Sugar. — There can be little doubt that the craze at present is for dry, i.e., sugar-free, wines. It is interesting to inquire whether this can be justified. We have seen that the total amount of sugar which can be consumed daily in the form of wine, no matter how sweet, is so small that it can be neglected from a merely nutritive point of view. The further question therefore arises, Is the com- paratively small quantity of sugar, which even the so-called ' sweet ' wines contain, in any way injurious to health ? Here, again, it is the gouty who are believed to be subject to special risks. There is no more reason, however, to believe that the sugar of wines, per se, 1 ' Gout : its Pathology and Treatment,' Cassell and Co., 1898, 394 FOOD AND DIETETICS is any more harmful to such persons than their acids are. It is interesting to note in this connection that it is the fortified wines which, as a class, are the sweet wines, and the natural wines which (with a few exceptions) are dry, and the suspicion naturally arises that it is the greater amount of alcohol in the sweet wines which renders them dangerous to the gouty (even granting that such danger has been proved to exist), rather than the sugar which they also contain. It is probable, indeed, that it is the combined presence of both sugar and acid in a wine which renders it harmful to the class of whom we are speaking rather than either of these ingredients alone. There is certainly some reason to believe that such a wine is more apt to excite an ' acid ' dyspepsia in gouty subjects than dry wines are. This may perhaps be due to the rapid absorption of sugar from the stomach in the presence of alcohol, and its replacement by a large quantity of highly acid gastric juice. It may perhaps be the case, too, that fermentation is apt to be restarted in a fortified wine once its alcohol is diluted in the stomach, and that this may give rise to the production of acid substances. Be the explanation what it may, the gouty man does well to avoid the fortified wines unless very dry, for such a dyspepsia is prone to be the signal for an attack of gout. 1 The action of the extractives of wine on the body is obscure. It has been supposed by some that their influence is akin to that of the extractives of meat, and they are believed to help in the making of blood. It may be worth while remembering that extractives are most abundant in old wines and those of good vintage. 1 The Lancet (1899, i. 525) gives the following list of practically sugar-free liquors which may be recommended to diabetics and the gouty : Per Cent, of Sugar. Champagne * Sans Sucre' (Hertz and Collingwood) . . o - 2 Californian Burgundy (Haig, Smith and Co., Manchester) . . 0-15 ,, Claret ,, „ „ .. 0-14 Australian Burgundy (Burgoyne) „ ,, .. o - 28 South Australian wines (Orion Brand, E. Burney Young, 35, Walbrook Street, E.C.) : Cabernet .. .. .. .. .. .. .. C14 Burgundy.. .. .. .. ,. .. .. 016 Reisling .. .. .. .. .. .. .. o - 2o Dry Imperial Champagne (Moet and Chandon) . . . . 0-65 Cider (G-aymer and Son) .. .. .. .. .. .. o - 7to2 - ia Harvey's Pale Ale . . . . . . . . . . . . . . None. Back and Co. 's Anti-diabetic Non-acid Whisky .. .. „ Dewar and Sons .. .. .. .. .. .. .. ,, Vibrona Champagne .. .. .. .. .. .. 0-13 ,, Sherry .. .. .. .. .. .. .. 020 Vitali's Italian wines o-ii to 0-17 SUMMARY 395 The volatile constituents of wine include the ethers and essential oils, the latter, along with certain highly-oxidized aldehydes, being probably chiefly responsible for the quality known as ' bouquet.' The action of these upon the body in health is probably slight, though they may exercise a modifying influence upon the intoxicating tendency of the alcohol along with which they occur. In disease, on the other hand, the ethers, and especially their volatile members, seem to have often a most valuable stimulating influence on the exhausted brain and heart. In attempting to summarize the points which have been raised in this discussion as to the use of wines in health, I cannot do better than quote the conclusions of Anstie : l i. Wines for daily use by healthy adults should not on the average contain more than ic per cent, absolute alcohol (by weight); 3 or 9 per cent, is better. 2. If wine be used as the daily drink, it is best, as far as may be, to use only one kind at a time and no other form of alcoholic liquid. 3. Sound natural wines are to be obtained at the best economic advantage from the Bordeaux district ; the red wines are to be preferred. 4. Rhine wines (white) are equally excellent, but more expensive. 5. Hungarian wines are also in many instances excellent, but they are unequal in quality owing to defects of manufacture. 6. Greek wines labour under the same defects. 7 The fortified wines, as a class, develop no proper vinous qualities till they have been for some years in bottle. Sherry, however, is greatly superior to the other wines of this class in the rapidity with which it develops the volatile ethers. 8. Fortified wines in small quantities, especially sherry, for the reason just named, are the appropriate stimuli of certain kinds of infantile and youthful debility, and of the enfeebled nervous system of old persons. 9. Half a bottle of a natural wine a day for a sedentary and a bottle a day for a vigorous and actively-employed adult affords a reasonable and prudent allowance of alcohol, and this quantity of wine, either alone or with water, will be enough to satisfy the needs of moderate persons for a beverage at lunch and dinner, the only two meals at which alcohol should, as a rule, be taken. The use of wines in disease will be considered in subsequent chapters. * ' On the Uses of Wines in Health and Disease ' (Macmillan and Co., 1877), p. 39, I 390 j CHAPTER XXII THE COOKING OF FOODS* The object of cooking food is twofold : i. /Esthetic — to improve its appearance and to develop in it new flavours. 2. Hygienic — to sterilize it to some extent and to enable it to keep longer. 2 ' It is an error to suppose that cooking increases the digestibility of food. That is only true of vegetable foods. The digestibility of animal foods is diminished rather than increased by cooking. This is true at least of the chemical processes of digestion, though the increased attractiveness of well-cooked food may render it indirectly more capable of digestion by calling forth a more profuse flow of psychical gastric juice (see p. 417). The application of heat in some form or another being the essential part of all ordinary processes of cooking, it is important to have clear ideas as to the effect of heat npon the different chemical constituents of food. The effect of heat on the proteids of the food is to coagulate them. It would be a complete mistake, however, to suppose that a boiling temperature is essential for bringing about this change, for all pro- teids, both animal and vegetable., are coagulated if their temperature is raised to 170 F. We shall subsequently see that ignorance of this fact is a fertile source of errors in cooking. If the temperature be raised much above this point, the proteid tends to shrink and harden, and the digestibility of the food in which it is contained is proportionately lessened. Of the carbohydrates of the food, starch is most affected by heat. 1 The reader may also consult on this subject ' The Chemistry of Cookery," by W. Matthieu Williams (London, Chatto and Windus t 1892); Thudichum's ' Spirit of Cookery ' (London, Bailliere, Tindall and Cox, 1895 1 ; and Sir Henry Thompson's 'Food and Feeding,' ninth edition (London, Frederick Warne and Co.), chapters v. and vi. 2 No animal parasite found in meat is capable of withstanding a temperature of 70° C. All ordinary forms of cooking will therefore render meat free from this source of infection. On the other hand, many pathogenic bacteria, such as those of splenic fever, malignant oedema, septicaemia, and chicken cholera, if present in the interior of meat, might quite easily escape being killed by the temperatures Usually reached in ordinary methods of cooking. THE COOKING OF FOODS 397 Dry heat converts starch into a soluble form, and ultimately into dextrin. This change occurs to a limited extent in the crust of bread, and also in the making of toast. Moist heat causes the starch grains to swell, and ultimately to rupture their cellulose envelopes, and the starch is then said to be gelatinized. That this change also takes place considerably below the boiling-point of water is shown by the following table of the gelatinization-points of different kinds of starch : x Oat 185° F. Barley 176° F. Rye 176° F. Wheat 176° F. Rice 176° F. Maize 167° F. Potato . . . . . . 149° F. Here again one sees that in the case of some starchy foods, at any rate, the change which it is the object of cooking to effect can be brought about at a comparatively low temperature. The effects of heat upon sugar have already been described, and it need only be mentioned here that the partial conversion of sugar into caramel is one of the means by which flavour is developed in food by cooking. The fats of food are not so much affected by heat as the proteids and carbohydrates. At high temperatures, however, as when one of the dry methods of cooking is employed, some at least of the fat may perhaps undergo a partial decomposition, with the libera- tion of free fatty acid. 2 This may explain why it is that hot fat is so much more apt to prove irritating to the stomach than cold fat, for it is not improbable than the fatty acid may reunite with glycerine to form neutral fat on cooling. Fat which has been heated and allowed to cool again is often found to have become more granular than it was before. This change is probably due to the driving off of water, and it tends to render the fat more brittle, and consequently more digestible than it was before. The change is well exhibited in the case of dripping, and also in fried bacon. With these preliminary considerations we may proceed to the study of the effects of cooking upon animal and vegetable foods respectively. 1. Cooking of Meat. The ideal to be aimed at in cooking meat is to decompose its red colouring matter (haemoglobin), so as to remove its raw appearance, 1 From Sykes' ' Principles and Practice of Brewing,' p. 70. s See also Matthieu Williams' ' Chemistry of Cookery,' p. 158. 398 FOOD AND DIETETICS and to do this without overcoagulating the solid proteids of the meat or removing from it its flavouring ingredients (extractives). We may glance very briefly at the means by which this ideal is to be attained in the ordinary methods of cooking. i. Boiling. — It is unfortunate that the term 'boiling' should be applied at all to any method of cooking meat, for it implies that the subjection of the meat to the temperature of boiling water (212° F.) is an essential of the process. But this, for the reasons indicated above, is a mistake. The red colouring matter of the meat is decomposed and rendered brown at a temperature considerably below that of boiling water, and by going up to the boiling-point one runs the risk of hardening the meat by overcoagulation of its proteids. That the boiling-point is not essential for the complete coagulation of the proteids can be most easily proved in the case of an egg. If two eggs are taken, and one kept in water at a temperature of 175° F. for ten or fifteen minutes, and the other for an equal length of time in boiling water, it will be found at the end of the experiment that the contents of both are solid throughout, but that in the case of the former they consist of a tender jelly, whereas in the boiled egg they are dense and almost leathery. Several so-called egg-boilers, indeed, have now been introduced which go upon the correct principle of cooking the egg at a temperature considerably below the boiling-point of water. Now, what is true of an egg holds good also for meat, and accordingly the first principle to be observed in the ' boiling ' of meat is to see that the temperature of the water does not rise much above that which is required for the coagulation of proteids. It is only by giving heed to this that one can achieve the first result desired — the abolition of the raw colour of the meat' with avoidance of overhardening. The second object to be aimed at, that of retaining all the flavour- ing constituents of the meat, also demands some care. The flavour of meat is due to its extractives and salts, and both of these are readily dissolved by water. If the water in which the meat has been cooked is to be consumed in the form of soup, the partial removal of some of these flavouring ingredients is not of much importance ; but if the meat alone is to be eaten, precautions must be taken to prevent their being dissolved out. One way of doing this is to use as small a quantity of water as possible ; for the larger the proportion of water to meat, the greater will be the amount of soluble substances removed. The quantity of COOKING OF MEAT 399 water, therefore, should be just sufficient to cover the meat, and no more. The other way of obviating removal of soluble substances is to seal up the piece of meat. This is best achieved by plunging it into boiling water, and leaving it there for a few minutes. This causes a rapid and complete coagulation of the proteid in the fibres of the meat, which forms an almost impermeable layer on the surface, and shuts in the soluble constituents. When this has been done, the temperature of the water should be lowered, and the process of cooking continued slowly. 2. In the process of roasting the heat is conveyed to the meat by direct radiation, instead of through the medium of water. Here, again, high temperatures should be avoided, except at the outset, when it is necessary to effect a sealing of the surface, for the same reason as in boiling. If the piece of meat is thin, the high tempera- ture to which it is first exposed not only seals the surface, but also coagulates the proteid throughout the whole thickness, so that the meat is practically cooked at once. This happens, for instance, when a chop is cooked on the grill, and the completeness of the sealing is shown by the fact that the water vapour produced from the fluids in the meat is unable to escape, and by its expansion causes the chop to assume that puffy form which is a sign of skilful cookery. In the case of a large joint the heat does not penetrate with sufficient rapidity to admit of instantaneous cooking, and in that case a long exposure to a lower temperature is required after the surface has once been sealed. Desiccation of the meat during this period is prevented by continuous basting, which forms a sort of impenetrable varnish of fat over the surface. Roasting, if properly performed, not only prevents the escape of the natural flavourers of the meat, but develops in it substances which are themselves of a sapid nature. This is due to a change which it brings about in the extractives on the surface, analogous to the alteration which sugar undergoes in its conversion into caramel. This results in the production of the dark-brown, sticky substance on the surface of a roast joint which is familiar to everyone, and which is sometimes termed osmazone. It is one of the most sapid substances known. 1 Recent experiments in America, however, have shown that if meat be cooked in water at 80° to 85° C, placing the meat in hot or cold water at the start has but little effect on the amount of material found in the broth (U.S. Dept. of Agriculture, Off. of Experiment Stations, Bull. No. 141, 1904). 2 The 'Unique' Gas Griller recently invented by Mr. A. E. Harris is the best roaster with which the writer is acquainted. For simplicity, cleanliness, efficiency, and economy it cannot be surpassed. 400 FOOD AND DIETETICS Experiments which have been made in America 1 show that roasts are cooked as quickly at a temperature of 175° C. as at 195 C. This is of practical importance from the point of view of economy in fuel. When cooked at ioo° C, a very much longer time is required to raise the inner temperature from medium (62° C.) to well-done (72 C.) than to cause the same rise at 195 C. or 175° C. There is, therefore, much less danger of over-cooking the meat at this temperature (ioo° C). 3. Baking acts in precisely the same way as roasting, the heat in that case being applied all round the meat at once, instead of only to one side at a time. The production of osmazone by this process is, however, rather limited. 4. Stewing is in many respects the ideal method of cooking meat. If properly performed, it coagulates without overhardening the proteids, while, owing to the fact that the juice is eaten along with the meat, none of the flavouring ingredients are lost. At the same time, the prolonged action of heat and moisture converts most of the connective tissue into gelatin, so that the fibres readily fall apart and the meat becomes very tender. Here, again, the secret of success consists in avoiding too high temperatures. It is not sufficient to place the pan by the side of the fire, and allow it to ' simmer ' instead of ' boil.' The use of a thermometer will show that the temperature of ' simmering ' and ' boiling ' water is really the same, i.e., 212° F., the only difference being that in the former case the heat is reaching the water more rapidly and more of it is wasted. In proper stewing the temperature should not be allowed to rise above 180° F. 2. Cooking of Fish. ■The flavouring ingredients of fish are even more easily dissolved out by water than those of meat ; and as fish has less flavour to start with, any loss is the more carefully to be avoided. For this reason boiling, unless very carefully performed on the lines above laid down, is not a suitable method of cooking fish. The experi- ments of Sir Henry Thompson 2 show that even when carefully performed it is apt to result in a loss of at least 5 per cent, of solid matter. For this reason cooking by means of water-vapour (steam- ing) is preferable, just as it, is in the case of some vegetables. 1 'A Precise Method of Roasting Beef.' The University Studies (Urbana, 111., U.S.A.), vol. ii., No. 4, May, 1907. 2 ' Food and Feeding,' p. 196. COOKING OF FISH 4°* Frying is a method of cooking specially applicable to some forms of fish, and demands a special word of description, especially as the process is so often misunderstood. The essence of frying consists in the sudden exposure of the object to be cooked to a very high temperature. This has the effect of. producing an instantaneous coagulation of the proteids on the surface, along with a slight degree of charring. Any escape of soluble substances is thus prevented, while the surrounding tempera- ture is so high that the fish or other substance is practically cooked throughout its whole thickness almost instantaneously. In order to attain this very high temperature, some form of fat must be used as a medium. Olive-oil or good cottonseed-oil are best. The oil should be heated in a deep pan almost to its boiling- point (the actual temperature is about 350° to 390 F.) ; and when this temperature has been reached the object to be fried should be suddenly plunged into the pan, and left for two or three minutes. The sputtering which ensues is due to the sudden conversion of the moisture on the surface of the object into steam. When this has ceased the cooking will be complete, and the object should be lifted out and the excess of oil allowed to drain off. It will be observed that this process differs entirely from the so-called ' frying ' usually practised in this country, in which the fat employed is regarded merely as a means of preventing the object from adhering to the surface of the shallow pan, in which a sort of roasting is really accomplished. 3. Cooking of Vegetable Foods. In the cooking of vegetable foods the objects to be achieved are different from those which one seeks to accomplish in the case of animal foods. Cellulose and raw starch are almost incapable of digestion by man, and hence the softening and rupture of the cellulose framework of a vegetable food and the gelatinization of its starch grains are the chief ends which it is the purpose of cooking to bring about. Cellulose can be softened, and, indeed, partly converted into sugar, by the action of acids, aided by heat. This is Nature's method of dealing with it. In its unripe state a pear or other fruit is hard and ' woody ' from the presence of a cellulose framework. In process of ripening the acids in the fruit, aided by the heat of the sun, effect a softening of this framework, with partial or complete solution of the cellulose fibres, the product being the sweet and soft ripe fruit. 26 402 FOOD AND DIETETICS This method is sometimes unconsciously imitated by man. The process of preparing ensilage is an exampWof it. Here, under the influence of fermentative bacteria, acids are produced in grass which, by the aid of moisture and heat, act upon the cellulose, and effect a partial conversion of it into sugar. In Germany a very similar process is employed in the conversion of cabbages into sauer-kraut. 1 The preparation known as sowans is an example of the operation of a similar agency on the cellulose of oatmeal. Ordinary porridge, also, when allowed to stand for some time, becomes a soil for the growth of acid-forming bacteria, and the products of the growth of these bring about some degree of softening of the cellulose in the particles of oatmeal. For this reason porridge is often found to be more digestible when stale than when perfectly fresh. Fig. 29.— Cells of a Raw Potato, with unruptured Starch Grains and Cellulose Framework. Another way of overcoming the cellulose obstacle, which may in a sense be regarded as a process of cooking, is by milling or grinding. This breaks up the cellulose framework, and allows the digestive juices to penetrate into the nutritive ingredients which it encloses. More commonly, however, one finds the same object accomplished by the combined action of heat and moisture. When exposed to 1 It is denied by some that cellulose is really acted upon by acids and th«, attribute the results obtained in the above instances to the action of other agencies. ux utuer COOKING OF VEGETABLES 4°3 moist-heat starch grains, as we have seen, swell up, their envelopes rupture, and they run together to form a paste or starch jelly. As Fig. 30.— Cells of a Partially Cooked Potato, the Starch Grains Ruptured. Fig. 31. — Cells of a thoroughly Boiled Potato; Cellulose Framework broken down. this jelly expands it presses upon and ultimately ruptures the frame- work of cellulose in which the grains are enclosed, and in this way 26 — 2 4°4 FOOD AND DIETETICS the two chief objects aimed at are achieved. The degree to which this occurs in different cases is very well shown in the accompanying diagrams (Figs. 29, 30 and 31), which illustrate the action of moisture and heat upon the structure of a piece of potato. It will be evident from these considerations that cooking is of immense importance in facilitating the digestion of vegetable foods, and the larger the proportion of cellulose present, the more essential does thorough cooking become. On the proteids of vegetables heat has an affect precisely similar to that which it exerts on the same constituent of animal food ; that is to say, they become coagulated. Now, the coagulation of proteids is accompanied by shrinkage rather than by swelling, and for this reason, if the cellulose framework encloses proteid only, it does not become ruptured ; and one can therefore readily understand that if a vegetable food contained proteid only its digestibility would be affected by cooking in a precisely similar way to that of animal food ; in other words, it would be rendered less rather than more digestible by the process. As a matter of fact, however, there are few vegetable foods which do not contain much starch as well as proteid, and hence it is that the general rule holds good that cooking increases their digestibility. Losses in Cooking. No matter how carefully cooking is performed, a certain amount of loss of the soluble constituents of the food during the process is almost inevitable. In the case of meat, it has been found by Johnston that — In Boiling. In Baking. In Roasting. 4 lb. of beef lose in weight .. 1 lb. 1 lb. 3 oz. 1 lb. 5 oz. „ mutton lose in weight 14 oz. 1 lb. 4 oz. 1 lb. 6 oz. By far the larger part of this loss, however, is due to water. This is phown by the following analyses given by Konig : COMPARATIVE COMPOSITION OF MEATS BEFORE AND AFTER COOKING. ■vt7„i.„ Nitrogenous _ , Extractive - ,, WaUr - Matter. FaU Matter. Salts - Beef : Per cent. Per cent. Per cent. Per cent. Per cent. Before cooking (raw) .. 7088 2251 452 -86 123 Same after boiling .. 5682 3413 750 '40 1-15 Same after broiling (as beefsteak) .. .. 5539 34-23 821 72 1-45 Veal cutlets : Before roasting (raw) .. 7i'55 20-24 638 -68 1-15 Same after roasting .. 5759 2900 11-95 -03 143 LOSSES IN COOKING 4°5 The actual loss of soluble matter is more clearly brought out when these figures are recalculated on the basis of dry substance :* COMPARATIVE COMPOSITION OF WATER-FREE SUBSTANCE OF MEATS BEFORE AND AFTER COOKING. Nitrogen. Nitrogenous Matter. Fat. Extractive Matter. Salts. Beef: Per cent. Per cent. Per cent. Per cent. Per cent. Before cooking . . After boiling After roasting . . Veal cutlets : • • 1237 1265 1227 7731 79-06 7673 i5'47 1738 18-41 298 •90 1 59 4-24 266 3'27 Before cooking . . After roasting . . .. 11-39 .. 1093 71-17 6836 2245 2818 232 •09 406 337 It will be observed that the loss is entirely confined to the extractive matter and salts. As far as their soluble constituents are concerned, vegetable foods behave similarly, the loss of salts especially being often very con- siderable. This point, however, has been fully dealt with when the composition of vegetable foods was described. 2 As regards water, the behaviour of the two classes of foods on cooking is entirely different, for vegetable foods tend to become richer in water when cooked, instead of losing it. The contrast between the two in this respect is very well shown in the following figures given by Forster : COMPARISON OF THE EFFECTS OF COOKING ON THE PROPOR- TION OF WATER IN ANIMAL AND VEGETABLE FOODS. Saw. Cooked. Beef.. . . 75 per cent. Boiled 55 to 59 per cent. Roast .. 56to63 Veal . . .. 78 .. Roast 60 to 64 ,, Flour 12 to 14 per cent. Bread . . 36 to 40 ,, , , chewed 70 per cent. Peas . . 14 per cent. Peas brose 68 to 78 per cent. Pea soup 90 per cent. Potatoes •■ 75 .. Potato puree . . 78 .. , , soup . . 91 Cabbage .. 87 „ Cabbage 85 to 90 per cent. One may, therefore, lay it down as a general proposition that animal foods become less watery as the result of cooking, while vegetable foods, on the contrary, become more watery. This is another explanation of the different effect which cooking exerts on the digestibility of the two classes of foods. The con- centration which meat undergoes when cooked is unfavourable to 1 Bulletin 21, United States Department of Agriculture, p. 87. 2 See also United States Department of Agriculture, Bulletin 43, ' Losses in boiling Vegetables,' etc. 4o6 FOOD AND DIETETICS digestion, while the dilution of the vegetable foods after cooking makes less demand on the digestive juices. This, too, is one reason why meat which has been cooked more than once is rather difficult of digestion. Not only are its proteids apt to be overcoagulated, but the relative proportion of fat is increased at the same time, and both of these facts militate against rapid and easy digestion. On the other hand, the increase of bulk which vegetable foods undergo as the consequence of taking up water in the course of cooking is apt, for reasons already explained, to throw a strain on the mechanical, as opposed to the purely chemical, functions of the digestive organs. The bearings of this fact upon the practice of Vegetarianism have been discussed at length in an earlier chapter. COMPOSITION OF SOME COOKED VEGETABLE FOODS (EXCLUDING PROTEID). 1 Names. Water. Fat. ^°^ Starch. Semolina .. .. .. .. .. 90-17 o - o8 0-04 7-24 Sago.. .. .. .. .. .. 8900 0-04 o-oi 9-35 Oswego .. .. .. .. .. 8732 o p 02 o-oi g-68 Vermicelli .. .. .. .. .. 87-14 o - oi 0-07 10-82 Arrowroot 2 .. .. .. .. ..93-41 Trace o-oi 4-83 Benger's Food, cooked with milk 8 .. 8830 2-57 0-23 817 Quaker Oats .. .. .. .. 92-48 0-32 0-09 6-25 Provost Oats .. .. .. .. 88-44 °'3^ °' 1 ^ 9' 00 Farola (fine grain) .. .. ..9024 0-02 0-06 ' 7-22 Farola (large grain) 8608 o-oi 0-15 11*06 Florador (large grain) 89-45 °' 01 • °'°8 8-67 Granola 87-40 0-03 o-io 9-42 Farola (medium grain) .. .. .. 8915 o-oi o - c6 8-89 Pearl barley 85-01 0-07 o-io 12-98 Mother's oats 89-72 0-45 0-15 870 Hominy 86-63 °'°9 °' 16 9/87 Slow Cooking. Food being a bad conductor, heat only penetrates into it very slowly. Wolffhiigel and Hiippe, 4 for instance, found that the temperature of the interior of a piece of meat weighing 9 pounds after four hours' boiling was only 88° C, or 12° below the boiling- point of water. The interior temperature of a roast varied from 70 to 95° C, according to size. Similar observations have been made by Sir Henry Thompson. 5 He found that the temperature 1 From analyses by Miss Katherine J. Williams. 2 West Indian, is. 4d. per pound. 3 Cooked according to directions on tin — 1 tablespoonful first mixed, 4 table- spoonfuls of cold milk, then a pint of boiling milk and water added (J water, § milk). All the rest of the foods were cooked with water alone. 1 Quoted in Bulletin 21, United States Department of Agriculture. 6 'Food and Feeding,' p. 97. SPECIAL COOKERS 4°7 close to the bone of a leg of mutton which had been boiled or roasted for some hours was never above 186 or 187 F. Hence it is that, if heat be applied to a piece of meat too rapidly, one simply wastes fuel and runs the risk of overcooking the outer layers. It is far better to allow a moderate amount of heat to act on the meat for several hours, and the longer the time allowed, the lower will be the temperature required, always assuming that it is kept above the coagulation-point of proteids. Various special forms of apparatus have been invented with the view of economizing fuel, and allowing of the prolonged action of a moderate degree of heat, some of which are certainly not as well known as they deserve to be. The simplest of these are constructed on the principle of an ordinary water-bath, and consist of a double pan, the outer being filled with water which is kept at, or near to, the boiling-point, while the article to be cooked is placed in the inner vessel. The heat only penetrates slowly to the latter, and never reaches the boiling-point, while any risk of burning is also prevented. The French bain-marie is constructed on this plan. Warren's Cooking-pot and Bailey's Cookers 1 are also good examples of the application of the principle. The Duplex Boilerette 2 is a modification of the bain-marie, in which the steam from the outer pan is prevented from escaping and reaches a high temperature, so that the food in the inner vessel can be actually boiled. Somewhat different from these is the Norwegian Self-acting Cooking Apparatus? This consists of an outer cylindrical vessel lined with non-conducting material, and an inner metal cylinder in which the object to be cooked is placed. If, for example, it is desired to boil a fowl, we place the latter in a saucepan of boiling water, boil it over the fire for five or ten minutes in order to ' seal up ' the surface, then remove the pan from the fire and place it in the inner cylinder. The outer lid is then closed, and, the escape of heat being thus entirely prevented, cooking is allowed to go on slowly for several hours. On opening the apparatus after the lapse of twelve or eighteen hours, the fowl will be found steaming hot, and, though thoroughly cooked, quite tender throughout. The apparatus acts on the principle of entirely preventing any loss of heat, and just as it prevents any heat getting out, so it can with equal efficiency prevent any from getting in. It may, therefore, be used as a 1 Bailey's Patent Cookers Company, 10, Bromley Road, Beckenham, Kent. 2 Manufactured by R. W. Welbank, North Newington, Banbury. 8 Supplied by Silver and Co., Sun Court, Cornhill, E.C. 4-o8 FOOD AND DIETETICS refrigerator, for keeping ices, etc., unmelted, quite as well as a cooker. The apparatus saves a great deal of time, trouble, and fuel, and is very useful to travellers and campers-out, or in any circumstances in which one wants hot food constantly ready. A little reflection will show that, in the use of an ordinary oven, a great waste of fuel is inevitable, for the metal of which the oven is constructed is an admirable conductor, and allows heat to escape as fast as it gets in. In order to prevent this and the waste of fuel which results from it, all that is necessary is to have the oven covered with some non-conducting material. The heat supplied by the fuel will then be unable to escape from the oven, and will all be utilized to cook the food, instead of being to a large extent dissipated into the surrounding atmosphere. An oven constructed on this plan has been devised by Canon Moore Ede for use in the preparation of penny dinners. The apparatus and its advantages are thus described by its inventor -, 1 ' It consists of a box 3 feet high, 2 feet wide, 1 foot 9 inches deep, with an outer case of sheet iron. The sides and lid are lined with i\ inches of felt, and inside this, again, is a further lining of tin. Underneath this box, which will hold 30 gallons, are placed two of Fletcher's Atmospheric Gas Burners. The felt being a non- conductor, nearly all the heat from the gas is utilized, and a com- paratively small expenditure of gas suffices to raise the temperature of the contents of the box to boiling-point, or to the beat required for the food which is being cooked. 2 ' When once the desired temperature is obtained, one of the burners can be turned off and the other lowered, when, owing to the prevention of radiation by the felt, it will be found that a merely nominal expenditure of gas will enable the temperature to be main- tained for hours, and even when the gas is totally extinguished many hours will elapse before food cooked will become cool. ' But except in the case of puddings which require rapid boiling, the cooking is done in an inner pan, which is placed inside the box, and which contains rather more than 20 gallons. The apparatus may be best described as a huge Warren's pot, with the additional advantage that the whole of the inner pan is surrounded by warm water. ' The space between the inner pan and the side of the box is filled 1 Now Dean of Worcester. 2 ■ Cheap Food and Cheap Cooking ' (London : Walter Scott), 1884. 8 Since the above was written, sundry alterations and improvements have been made which considerably increase the economy and efficiency of the apparatus. EDE'S APPARATUS 4°9 with water, which is kept at the temperature desired by means of the gas burners. • The chief advantages of this apparatus are as follows : ' Economy in first cost of the apparatus, which can be procured from Messrs. Emley of Newcastle. ' There is little, if any, smell of cooking. ' The apparatus can be placed in any room, and no arrangement of flues is required. The iron pipe which takes away the fumes of the gas can be carried into the chimney, if there is one in the room, or, if there is no chimney, through a small aperture in the window. ' As the felt retains the heat, the exterior of the box remains cool, and the temperature of the room is scarcely affected ; indeed, so slight is the smell of cooking, so little the heat radiated, that the apparatus might almost be placed in the schoolroom itself. ' Owing to the inner tin and the box itself being firmly closed, no evaporation takes place, and all the nutriment and flavour of the food is preserved. ' Surprising though it may sound, there is a gain of nearly 30 pet cent, in quantity in the case of meat cooked in this way ; in pre* paring soup less of the nutrition of the meat is lost, and vegetables are more palatable as well as more nutritious when cooked in the manner described. ' Most food is improved by being cooked very slowly ; this can be easily done by this apparatus, and also it can be so adjusted that each kind of food can be cooked at the temperature which most effectively brings out its nutritious qualities ; this for meat is at about 170 F., for pulse about 200°. ' The expenditure for fuel is very slight ; gas costing seven-tenths of a penny will in this apparatus raise 5 gallons of water to boiling- point, and less than 3d. is sufficient to boil 30 gallons. Once boiled, the temperature can be retained at a nominal expenditure of gas. ' Another advantage is that no food can be burned, and no care is required to prevent that very common catastrophe. The food once placed in the inner tin in proper proportions, and the space between the inner and outer case filled with water, the lid is closed and the gas turned on till the required temperature is reached; it is then lowered, and the dinner is left to take care of itself. As it is often convenient to prepare the dinner the previous afternoon, it is not unfrequently left cooking at a low temperature the whole night. All the labour entailed by keeping up a coal fire is avoided, and also the constant attention usually necessary to prevent burning. 'The only defect of the apparatus is that it is not capable of 4io FOOD AND DIETETICS baking, but in the case of school dinners I think this wiil be found of little consequence.' The Aladdin Oven, invented by Dr. Edward Atkinson, is on the same principle. 'It is a simple iron box, closed in front by a door, and having an opening in the top that communicates with a tube to let off any superfluous steam. This box is surrounded by another, whose top and sides are made of non-con- ducting material for the purpose of holding the heat. A standard, on which this box is set, and a lamp underneath complete the apparatus.' 1 A clearer idea of the structure of the oven will be obtained from the accompanying diagram, borrowed from Dr. Atkinson's interesting book (Fig- 32). The oven can be heated either by a kerosene lamp or by a small gas burner, and it will raise the tempera- ture of 40 pounds of meat and 15 quarts of water to 180° F. in the space of seven hours, and if the lamp is then removed the temperature undergoes no appreciable diminu- tion for fully four hours. Dr. Atkinson calculates that in an ordinary oven 2 pounds of fuel must be expended for every pound of food cooked, whereas in his apparatus i\ pounds of fuel will cook 60 pounds of food, and that the daily cost of cooking by it amounts to only £d. per person for a family of ten. The saving of trouble also is enormous, for the apparatus can be left to cook by itself overnight. In 1889 and 1890 a number of experiments were made in America by Mrs. Ellen H. Richards and Mrs. Mary H. Abel on the best methods of cooking food. They state in their report 2 that 'for simplicity, effective use of heat, economy of fuel and development of flavour in the food cooked, combined with increase of its digestibility, 1 Edward Atkinson, ' The Science of Nutrition and the Art of Cooking in the Aladdin Oven ' (Boston, Damrell and Upham), 1896. See also ' How to Make and Use an Aladdin Oven,' by the same author and publisher (1901). 2 Bulletin No. 21, United States Department of Agriculture, p. 94. Fig. 32. — The Aladdin Oven. (After Atkinson.) THE ALADDIN OVEN 411 the Aladdin Oven is an apparatus far exceeding in merit any other now in the market.* A friend of the writer's has used the oven for several years with the most satisfactory results, and his experience entirely bears out the favourable opinion expressed in the above report. The Aladdin Oven cannot be obtained ready made in this country, but it can easily be constructed by any intelligent tinsmith. It is interesting to note that the advantages of slow cooking are well known to some savage tribes, and in this respect the civilized cook has something to learn from them. This is the method of cooking practised by the Kanakas of the Friendly Islands, as described by Mr. F. T. Bullen : l * A hole is scooped in the earth, in which a fire is made (of wood), and kept burning until a fair-sized heap of glowing charcoal remains. Pebbles are then thrown in until the charcoal is covered. Whatever is to be cooked is enveloped in leaves, placed upon the pebbles, and more leaves heaped upon it. The earth is then thrown back into the cavity and well stamped down. A long time is, of course, needed for the viands to get cooked through ; but so subtle, is the mode that overdoing anything is almost an impossibility. A couple of days may pass from the time of ' putting down ' the joint, yet when it is dug up it will be smoking hot, retaining all its juices, tender as jelly, but, withal, as full of flavour as it is possible for cooked meat to be. No matter how large the joint is or how tough the meat, this gentle suasion will render it succulent and tasty ; and no form of civilized cookery can in the least compare with it.' No better illustration of the advantages of slow cooking could well be found. 1 • The Cruise of the Cachalot ' (London : Smith, Elder, and Co.), p. 273. (4**1 CHAPTER XXIII THE DIGESTION OF FOOD IN HEALTH The object of the present chapter is not so much to describe the merely chemical processes of digestion, which are fully dealt with in all text-books of physiology, as to consider the bearing of some physiological facts upon such matters as the selection of foods, the arrangement of meals, and other practical questions in dietetics. As it is difficult to treat the subject quite systematically, it will be more convenient to arrange the principal facts under separate headings. Digestion in the Mouth. 1 The mouth stage of digestion is mainly a mechanical one, and its object essentially protective. By reducing the food to a pulp, by breaking up and softening hard particles, by neutralizing or diluting irritating constituents, such as acids, and by surrounding the whole mass with a wrapping of mucus, it is sought to guard the stomach against the effects of the ingestion of injurious substances. In the accomplishment of this object thorough chewing is of the first importance, and if the food is to be thoroughly chewed it must be eaten slowly. 2 To 'bolt' the food in the manner — as it has been described — in which one posts letters interferes gravely with proper disintegration ; and many a case of dyspepsia, too, is kept up, if not actually produced, by imperfections of the teeth. At the same time, it must not be forgotten that there is a chemical side to mouth digestion as well. Starch, under the action of the ptyalin in the saliva, and by processes which need not here be 1 For a fuller consideration of this subject, see a series of papers (' Observations on Mastication '), by Dr. Harry Campbell, published in the Lancet, 1903, ii. 84, 115, 260, 375. 2 Attention has in recent times been called to the great importance of thorough mastication by the experiments and observations of Mr. Horace Fletcher, who has proved not only how greatly very prolonged chewing facilitates digestion, but also that if the process is carried out sufficiently thoroughly the appetite and requirements of the body are satisfied by much less food than the amount usually taken. For a description of his method see a paper by Dr. Hubert Higgins (' Is Man Poltophagic or Psomophagic ?'), Lancet, 1905, i. 1334, I 4 I 7- DIGESTION IN THE MOUTH 413 described, is converted into soluble substances. The degree to which this occurs varies, partly with the form of the starch grain, and partly with the consistence of the food and the reaction of the medium. Some forms of starch — e.g., that of rye and maize — are much more readily acted upon by the saliva than others, such as potato starch ; raw starch, owing to the cellulose coating of its grains, is hardly affected at all. Porous foods, into which the saliva can readily penetrate, are more easily attacked than dense and compact masses of food, such as new bread. Moist substances, too, offer less resistance than those which are dry. As regards this matter Pereira has pointed out an analogy in the preparation of tinctures by percolation, the substance to be extracted being much more readily acted upon if it has been subjected to a preliminary moistening. In accordance with this, it has been found that dry bread, taken alone, is digested to a much smaller extent in the mouth than if it be eaten along with water. A natural provision is made for the larger amount of ptyalin required for the digestion of dry foods, for Pawlow found, in his experiments on dogs, that such articles caused a much greater reflex flow of saliva than moist foods did. The latter, indeed, seemed hardly to provoke any flow of saliva at all. We have here a con- firmation of the view that the uses of the saliva are mainly mechanical, for the object of the increased flow is apparently to moisten the dry food, even more than to digest its starch. In describing the influence of such articles as vinegar, malt liquors, and wines, on salivary digestion, it was pointed out how marked was the retarding effect of the acids which these fluids contain upon the action of ptyalin, and the same was found to hold good for the tannic acid in tea. It must be noted, however, that the merely chemical effect of these beverages may be to a large extent counter- acted by the more profuse flow of saliva which they often induce. All sour fluids possess this property, and the warmth of tea and the bitter ingredients of beer enable them to exert a similar effect. Wines, however, do not seem to be powerful sialogogues, though some of them, e.g., sherry, excite a more abundant secretion of mucus. 1 Digestion in the Stomach. Just as the chief object of digestion in the mouth is to protect the stomach, so the chief object of digestion in the stomach is to protect the intestine. Observations of the results of complete removal of the 1 See Aitchison Robertson, ' The Salivary Digestion of Starch in Simple and Mixed Diets,' Journal of Anatomy and Physiology, 1898, xxxii. 615. 4M FOOD AND DIETETICS stomach in man have shown that its co-operation cannot be regarded as essential to the complete digestion and absorption of an ordinary mixed diet, provided the latter be presented to the intestine in a suitable mechanical form. 1 The chief functions of the stomach, indeed, are probably these: 2 i . To act as a reservoir. 2. To reduce the food to a semi-fluid form. 3. To sterilize the food — at least in part. 4. To regulate its temperature. 5. To effect a slight degree of absorption. We shall briefly consider each of these functions separately. 1. By acting as a reservoir, the stomach enables us to take our food in considerable quantities at a time; i.e., it renders meals possible. The practical convenience of this needs no demonstration, but some other points connected with the question of meals require to be raised. And firstly it may be asked, At what intervals should meals be taken ? Is it better to take several small meals, or to consume one's daily supply of food at one or two sittings ? The reply undoubtedly is that several small meals are best. The ' one-meal-a-day man ' is at a double disadvantage : (1) he is apt to overburden the mechanical powers of his stomach by the mere weight of food introduced into it at one time ; (2) some of the constituents of food so introduced are partly wasted, owing to the assimilative powers of the tissues being unable to keep pace with the flood of nutriment which reaches them all at once. Let us consider each of these points for a moment. (1) The capacity of the human stomach is very variable, both in different individuals and in the same individual at different periods of life. On the average it may be put down as from 2 to 4 pints, 3 and in the case of solids at about 2 pounds. If it be remembered that the total amount of solid food, required daily is at least 3 pounds, it is evident that if one were to take the whole of this in one meal he would be apt to overtask the powers of the stomach, or to produce a gradual dilatation of the organ. In the case of persons of feeble digestive power the limitation of the bulk of meals is of even greater importance. For them ' little and often ' is the golden rule. (2) There is evidence to show that more food is wasted when it is all taken at once than when it is spread over a considerable time. The waste chiefly affects the proteids, which are the most rapidly 1 Schlatter, Lancet, 1898, i. 141. 3 An additional function is the establishment of osmotic equilibration between the blood and the fluid food. See Jona, ' The Osmotic Pressure of Liquid Foods ' (Bio-Chemical Joum., 1909,^.462). 3 See Gillespie, 'The Natural History of Digestion," p, 274, and the sa,me author's ' Modern Gastric Methods,' p. 3, 1899. ARRANGEMENT OF MEALS 415 digested of the constituents of the food, and is partly due to defective absorption and increased opportunity for intestinal putrefaction. Ranke, for instance, found that if he ate 1,800 grammes of meat all at once the loss by the bowel amounted to 12 per cent., but if the same quantity of meat was divided into three meals the waste was only 5 per cent. The loss of proteid must also be attributed in part to defective assimilation. If the tissues are so flooded with proteid that they are unable to assimilate the whole of it, the excess appears to be rapidly excreted in the form of urea instead of being stored up. This, at least, was the conclusion which Krummacher 1 drew from his experiments on dogs, in which he tested the effects of giving a certain quantity of food in one meal, and then when divided into five meals. He found that more nitrogen was excreted in the former case than in the latter. It follows from this that care must be taken not only to have enough total proteid in the diet, but to see that it is evenly spread over the day, so that the tissues may not at one time be repleted and at another be compelled to draw on their own reserves. The tissues, in fact, may be compared to a reservoir, the outflow from which is pretty constant, and to which, if it is to be kept full, the inflow should also be fairly steady. A practical example of the neglect of tliis principle is thus given by Clement Dukes (he is speaking of the unwise division of meals often observed at public schools) : 2 ' For instance, if bread-and-butter only be provided for breakfast, say at 8 a.m., this will be digested and used up by the system long before dinner takes places at 1.30 p.m., and therefore from about 11 a.m. to 1.30 p.m. the body will be starved. Then at dinner the boy can only eat a certain amount of food, however much the caterer may supply, and thus the defect of the two hours and a half of starvation is never recovered, although growth must take place all the same.' The hours of meals have varied greatly even in the same country at different periods of history, and must depend largely upon con- venience and upon habits as regards work, etc. If possible, dinner, the principal meal of the day, should be taken after work is over, so that comparative repose may be enjoyed after it. As a matter of actual observation, Voit found that 50 per cent, of the day's proteid, 61 per cent, of its fat, and 32 per cent, of its carbohydrate, was taken at dinner. 2. The second function of the stomach is to reduce the food to a semi-fluid form. This is done partly by the solvent action of the 1 ' Wie beeinflusst die Vertheilung der Nahrung auf mehrere Mahlzeiten die Eiweisszersetzung ?' Zeit. f. Biolog., 1897, xxxv. 481. * ' School Diet,' second edition, p. 9. 416 FOOD AND DIETETICS gastric juice, and partly by the mechanical movements of the stomach walls. We may therefore glance for a moment at — The Secretion of Gastric Juice. Until recent times it was supposed by physiologists that the secretion of gastric juice was chiefly brought about by mechanical stimulation of the mucous membrane of the stomach by the particles of food introduced into it. The elaborate and ingenious experiments of Pawlow, 1 however, have shown that this is a mistake, and that the chief factors concerned in bringing about the secretion are (i) psychical and (2) chemical, and that mechanical action plays quite a secondary part, if, indeed, it comes in at all. The psychical factor is intimately bound up with the sensations of appetite and hunger. It is difficult to define these terms exactly, though appetite may be described as the desire for food, and hunger as the need for it. 2 Appetite is dependent partly upon hunger — as Von Noorden has it, it is to be regarded as ' the reflection of the Calorie-requirements of the tissues ' — but partly also upon the state of the stomach and alimentary tract generally. Thus, an individual may complain of ' hunger ' even although the stomach is full, as in those cases where a fistula exists high up in the intestine, and prevents the food from reaching the tissues ; 3 or the stomach may be quite empty, and yet no complaint of hunger made, as, for example, in the case of patients who are being fed per rectum. In disease of the stomach, too, or where it is in a state of functional anaesthesia, appetite may be in abeyance, although the need for food (' tissue hunger ') exists. In such a case the introduction of food into the stomach may suddenly awaken appetite. Pawlow mentions a good example of this in his own experience. He was convalescent from a trifling illness, and in spite of some days' .abstention from food still suffered from complete loss of appetite. He then swallowed 1 ' Die Arbeit der Verdauungsdriisen,' Wiesbaden, 1898. Pawlow's chief results have been confirmed, in the case of the human subject, by Schiile (' In wie Weit Stimmen die Experimente von Pawlow am Hunde mit den Befunden am normalen menschlichen Magen ueberein?'), Deut. Arch. f. Klin. Med., 1901, lxxi. in. 8 This probably does not cover the whole difference between appetite and hunger. The sensation of pleasure seems inseparable from the former, that of pain from the latter. Appetite is more particularly related to the stomach, and has its seat in the brain cortex. Hunger appears to be more connected with the nutritive needs of the tissues, and possibly affects more the centres which preside over organic life. There is reason, too, to believe that the sensation of hunger is peculiarly associated with a deficiency of proteids in the blood, and can only be really allayed by a supply of them in the food. Fat, on the other hand, seems to have a special power of appeasing appetite. Advantage of this fact has been taken by Oertel in his dietary for the treatment of obesity (see p. 484). » For a description of such a case see Busch, Virchom's Anhiv., 1858, xiv. 140, APPETITE AND HUNGER 4 T 7 a glass of wine, and immediately a strong desire for food arose. This is a case in which Vappetit vient en mangeant. While, then, appetite can hardly exist without some degree of hunger, the latter may be present without the accompaniment of the former. In health, however, the two seem to co-exist, and appetite is a true index of the amount of nutriment required by the tissues. It may be that some people, otherwise healthy, have habitually less appetite than corresponds to the true needs of their tissues, and this may explain some cases of malnutrition. Von Noorden 1 is of opinion that this state of things may be brought about by defective feeding in childhood, i.e., by the use of food which does not make sufficient demand upon the digestive powers, and allows the stomach and intestines to grow up in a condition of functional feebleness. Hence in after-life, when compact and highly nourishing food cannot be obtained, a more bulky diet satisfies the stomach before the needs of the tissues are really supplied. For this reason, also, such persons are often poor eaters of fat, for it is difficult to take much fat without repugnance in a mainly animal form, but comparatively easy when diluted with a large bulk of vegetable food. This discussion has led us away somewhat from our starting- point — the relation of appetite to the secretion of gastric juice. The experiments of Pawlow, already mentioned, have shown that appetite is the most powerful excitant of gastric secretion. The mere sight or smell of food and the act of chewing are followed, if appetite be present, by a profuse flow of a peculiarly powerful gastric juice which may continue for as long as four hours. Hence the importance for digestion of such aesthetic aids to appetite as agreeable surroundings, a well-appointed table and good cooking, and the use before dinner of such ticklers of the palate as ' sherry and bitters ' or the savoury articles usually classed on the menu as hors d'asuvres. 2 The other factor mainly concerned in producing gastric secretion is a chemical one, the active agents being the chemical constituents of the food. The remarkable fact has recently been elicited that the stimulus so exerted is not a general, but a specific one, each food calling forth a supply of those ingredients of the juice specially required for its own digestion. Some easily dissolved foods, for example, such as meat, produce a flow of juice large in quantity, but poor in ferments ; other foods, such as bread, which are more difficult of solution, cause a scanty but very concentrated juice to be * Berliner KliniK, 1893, vL, Heft S5- a It is an important fact, however, that the human stomach appears to be capable of digesting even in the absence of all psychical influences— «.?., if food be introduced into it without the subject's knowledge (see Schule, op. cit.). 27 418 FOOD AND DIETETICS secreted which is very rich in ferment ; milk, again, which is one of the most easily digested of all foods, produces only a moderate amount of juice, and that of weak digestive power. This capability of foods to bring about the secretion of a specific kind of gastric juice specially adapted to the requirements of their own digestion is of importance for this reason, that it enables ' digestive habits ' to be very readily established. Let us suppose, for instance, that a patient has been confined for some time to. an exclusively milk diet. His stomach soon acquires the habit of manufacturing a secretion specially adapted for the digestion of milk. But this, as we have seen, happens to be a secretion of small digestive power. If the diet be now changed to .one, say, chiefly composed of bread, some time may elapse before the specific secretion specially suited to the digestion of bread is established, and meanwhile dyspepsia may result. This may explain why sudden changes of diet are to be avoided. ' If,' says Pawlow, 1 ' one alters the diet of an animal and goes on giving the new food, one finds that the ferments contained in the digestive juices accommodate themselves more and more every day to the altered diet. If, for example, one feeds a dog for some weeks on milk and bread only, and then changes to a purely meat diet, which contains much more proteid and almost no starch, one observes a gradual increase in the proteid ferments of the pancreatic juice. The capability of digesting proteid increases day by day, whilst, conversely, the starch-digesting power falls off. This adaptation takes place much more readily in some animals than in others. Where it does not easily occur, a sudden change of diet may produce considerable digestive disturbances.' In the light of these facts one can understand the enormous importance of establishing good ' digestive habits ' in the young. If a child is encouraged to avoid fat, for example, he may ultimately lose the power of producing the secretion specially suited to the digestion of fatty foods, and may thus, with the best intentions, be unable to eat much fat all his life afterwards, and so suffer from impaired nutrition. This is the more to be regretted as there is reason to believe that inability to digest fat renders one peculiarly liable to become the victim of tuberculous diseases. Curiously enough, it is not all chemical constituents of the food which are capable of exciting a secretion of gastric juice. Egg- white, for instance, produces none, nor do the albumoses, peptone, starch or sugar ; milk, gelatin, and water produce slight secretion, while the extractives of meat are amongst the most powerful excitants 1 Op. ck., p. 52. ACIDITY OF THE GASTRIC JUICE 419 known. Soup makes a good beginning to a meal, because it stimulates a flow of gastric juice, not only by its warmth, but also by virtue of the gelatin and .extractives of meat which it contains. On the other hand, fat seems actually to restrain the secretion of gastric juice even when other foods are present as well. This is no doubt one reason why fat things are difficult to digest, and why skim milk is ' lighter ' than milk rich in cream. It teaches us also that such articles as cod-liver-oil should be given some time after meals, when the gastric juice has been already poured out. Acidity of the Gastric Contents. The total amount of hydrochloric acid present in the stomach depends upon the quantity of gastric juice secreted. The proportion of acid present in the juice is very constant in the same individual. In different persons, however, it varies from about 1 to i\ parts per 1,000 of juice. The cause of these individual differences is not quite clear, but they seem to' depend to some extent upon the kind of food habitually taken, persons who live largely upon meat having usually a more acid juice than those who partake more freely of vegetables. 1 This is another example of the establishment of a ' digestive habit,' to which reference bas already been made. The total amount of acid present in the stomach rises gradually during the first three-fourths of the period occupied by the digestion of a meal, and then falls off rapidly during the remaining fourth. The faM in acidity is probably to be explained by the pouring out towards the end of digestion of a neutral or slightly alkaline juice from the pyloric end of the stomach. Of the total amount of acid present in the gastric contents at any moment, only a small part exists in the free form ; the larger part is in a state of combination. The hydrochloric acid first poured out is fixed by any bases which may be present in the food {e.g., car- bonates and lactates), and after these have been neutralized the proteids of the food lay hold of the rest of the acid and enter into organic combination with it, and it is only after these have been saturated that the acid is able to make its appearance in the stomach in a free form. The exact moment at which this occurs must ob- viously vary greatly with the amount of food in the stomach and the proportion of proteid which it contains. The larger the meal and the richer it is in proteids, the longer will the appearance of 1 See Verhaegen, ' Physiologie et Pathologie de la Secretion Gastrique,' Paris, 1898, p. 9; also Gillespie, 'The Natural History of Digestion,' p. 106. Schiile, however, found that the kind of food has very little influence on the percentage of acid in the gastric juice {op. cit.). 27 — 2 420 FOOD AND DIETETICS free acid in the stomach be delayed. As an illustration of this, the following observations of Penzoldt 1 may be cited : After 7 or 8 ounces of sweetbread free acid was present in one hour. After 7 or 8 ounces of chicken free acid was present in two hours. After 7 or 8 ounces of beef- steak free acid was present in three hours. After 5£ ounces of vegetable food, free acid was usually found in one or one and a half hours ; but if the food was one very rich in proteid, e.g., peas or lentils, its appearance was delayed for three hours or more. The amount of free acid present does not usually exceed i part in 1,000 of the stomach contents, arid its presence persists for about one and a half hours. We must now briefly consider the relations of the acidity of the stomach (i) to the gastric digestion of starch ; (2) to morbid gastric sensations. Digestion of Starch in the Stomach. There is no doubt that ptyalin is rapidly killed by free hydro- chloric acid, and even if o - i per cent, is present its action on starch ceases entirely. The effect of combined hydrochloric acid on the ferment, however, is by no means so certain, and the experiments of different authorities on the subject have yielded very discordant results. 2 It seems to be generally agreed, at any rate, that the presence of anything like a large amount of combined acid is highly inimical to the conversion of starch. It follows from this that the digestion of starch in the stomach is not likely to continue for more than half an hour — or at most one hour — after the taking of a meal. Obviously, the process can go on longer the greater the proportion of hydrochloric acid which passes into the combined form ; in other words, the presence of a large amount of proteid in the food is favourable to the digestion of starch in the stomach, whereas if the meal consists exclusively of carbohydrates the process must sooner come to an end. This is one of the many advantages of a mixed diet. Observations with the X rays have shown further that the food last swallowed is received into the centre of the mass already present in the stomach, and does not for some time come into contact with the mucous membrane and, therefore, with the gastric juice. The 1 Deut. Archiv. f. Klin. Med., 1894, liii. 209. 2 See Gillespie, op. cit., p. 157 ; Aitchison Robertson, Edinburgh Medical Journal, 1896, xli., part ii. 1010 ; A. E, Austin, Boston Medical and Surgical Journal, 1899, cxl. 325. MORBID GASTRIC SENSATIONS 421 central portion of the contents can, therefore, retain an alkaline reaction for a considerable period, during which ptyalin can go on acting. This justifies the conventional arrangement of a dinner in which the starchy course (pudding) comes after the proteid course (meat). Relation of the Acidity of the Stomach Contents to Morbid Gastric Sensations.- In health digestion proceeds quite unconsciously and without the production of any sensation at all. In morbid conditions of the stomach, however, digestion may be accompanied by sensations of pain, and these seem to arise in at least two ways : (1) from disorder of the motor functions of the stomach ; (2) from abnormal conditions of the mucous membrane. The former of these we shall consider later. The latter seems to be of two sorts : (a) where the mucous membrane is unduly sensi- tive to the total acidity of the contents ; (b) where free acid alone produces pain. The former of these conditions seems to be present where actual lesions of the mucous membrane exist — e.g., in ulcer and in carcinoma ; the latter is apparently more often of the nature of a neurosis— a hyperesthesia of the nerves of the mucous mem- brane, though it is possible that in extreme degrees of such hyper- esthesia pain may be produced even by combined acid. Where the total acidity causes pain the condition is likely to be aggravated by foods rich in proteid, such as meat, for these, as we have seen, call forth an abundance of juice, and therefore of acid. If, on the other hand, free acidity alone excites the sensation, such foods are likely to be beneficial, for they delay the period at which free acid appears, and also lessen its amount. In accordance with this explanation, I think it will be found that patients who are suffering from ulceration of the stomach complain of pain after meat, but can digest milk with com- fort ; for milk not only neutralizes much acid by means of its bases, but in itself calls out the secretion of a weak and scanty gastric juice. On the other hand, one usually finds that patients with functional dyspepsia and hyperesthesia of the stomach suffer less from meat than from foods which, being poor in proteids, allow of the early appearance of uncombined hydrochloric acid. These considerations are of importance in helping one to select a suitable dietary for dyspeptics. 412 FOOD AMD DIETETICS Movements of the Stomach. In studying the movements of the stomach, one must distinguish quite sharply between the cardiac and the pyloric end of the organ. There is no doubt that this distinction is not grasped as clearly as it ought to be. The two ends are distinct, both anatomically and functionally. The cardiac end secretes both pepsin and hydro- chloric acid, the pyloric end pepsin alone. The former has but feeble motor power ; the movements of the latter are frequent and powerful. This functional difference would be found, I think, to explain to some extent the respective liability of the ■two ends to different diseases, but that subject cannot be entered upon here. Nor 'is it commonly recognised that the two portions of the stomach are separated from each other by a thickening of the muscular coat — the transverse band — which acts as a kind of ' pre-pyloric sphincter.' The existence of this sphincter was long ago pointed out by Retzius. 1 It is situated at a variable distance from the pylorus, and, though it cannot always be demonstrated in the cadaver, it is probably always present in the living organ. Thanks to the existence of this sphincter, the stomach is able to ' sort ' its contents into those which are in a fit state to be passed on into the intestine, and those which must be kept back to be further acted upon by the gastric juice. The sorting is probably brought about in this way : Shortly after the food enters the stomach feeble peristaltic waves are set up in the cardiac end, which keep up a slow revolution of the contents, sufficient to ensure their complete mixing with the gastric juice, but not of sufficient strength to exercise any real pressure on the food masses such as might break them up mechanically. These waves seem to stop at the transverse band, their point of cessation being marked in the living stomach by the appearance of a sulcus. They are strong enough to squeeze the fluid part of the contents past this constriction on into the pyloric end, but are not sufficiently powerful to do the same for solid, undigested lumps. In this way the digested parts of the food are separated from the rest. The movements of the pyloric end are, as has already been mentioned, much more active than those of the fundus. It is here that the food is mixed with the gastric juice, rubbed down into a more or less fluid consistency and expelled into the duodenum. The mechanism by which this takes place is as follows (Cannon) : 1 Mullet's Archiv., 1857, p. 74. He describes the ' transverse band ' as the • sphincter antri pylori.' MOVEMENTS OF THE STOMACH 423 Whilst food is present in the stomach constriction waves are seen continually coursing over the antrum towards the pylorus. The fundus meanwhile serves as an active reservoir for the food, and squeezes out its contents gradually into the pyloric portion. The stomach is emptied by the formation, between the fundus and antrum, of a tube along which constrictions pass at regular intervals of fifteen to twenty seconds. The contents of the fundus are pressed into the tube, and the tube and antrum slowly cleared of food by the waves of constriction. The food in the pyloric portion is first pushed forward by the running wave, and then by pressure of the stomach wall is returned backwards through the ring of constriction, being thus thoroughly mixed with gastric juice. Finally, when the solid food has been thoroughly triturated by the constrictions, the pylorus opens and allows the contents of the antrum to escape. The activity of the peristaltic movements of the stomach seems to depend in part on the temperature of the contents, and in part on their chemical nature. Mere mechanical contact seems to have but little stimulating effect upon them. Hot food increases the frequency and vigour of the movements, and so does a highly acid condition of the contents. It may be for this reason that the movements become more vigorous as digestion proceeds. Such stimulating substances as mustard, alcohol and carbonic acid gas seem to have a similar effect. The length of time which elapses between the swallowing of food and the first opening of the pylorus is variable, depending chiefly upon the consistence of the food and the temperature and reaction of the stomach contents. Fluids, unless they contain much solid matter in solution, begin to escape almost immediately, water, indeed, whilst it is still being swallowed. Any excess of fluid taken with a solid meal is probably also passed on almost at once, and so cannot seriously dilute the gastric juice. Solid food can only escape after it has been reduced to a fluid or semi-fluid consistency, and this must obviously depend to a large extent upon its physical characters and density. Busch, in his observations upon a patient with a duodenal fistula, saw the escape of food after as short an interval as fifteen or thirty minutes. 1 The larger part of a meal, however, probably does not pass out of the stomach till most of it has been completely digested, and half an hour after that has taken place the stomach may be regarded as empty. 1 Virchow's Archiv., 1858, xiv. 140. 424 FOOD AND DIETETICS Warmth tends to accelerate the opening of the pylorus, but a very acid condition of the stomach contents has a contrary effect. Organic acids have perhaps a more powerful influence in this direction than hydrochloric acid, and may induce an actual spasm of the orifice. A dose of alkali may relieve the pain which such spasm causes. Hence it is only towards the close of digestion, when the acidity of the stomach contents has been reduced by the addition of the neutral or slightly alkaline secretion of the pyloric end, that the conditions most favourable to the escape of food come into existence. It has been found, also, that the duodenum exercises a controlling influence over the pylorus, distension of it inhibiting the opening which would otherwise take place. Rate of Digestion of Different Foods. Seeing that food cannot be passed on into the intestine until it has been brought into a state of solution, it is obvious that we have, in the period which elapses before the stomach is empty after the taking of any particular article of diet, a criterion of its digestibility as far as the stomach is concerned. In previous chapters the relative digestibility of different foods has been considered in detail, but it may be well at this point to summarize our knowledge of the subject. Most of our information on this matter has been derived from the experiments of Penzoldt on healthy men. 1 He found, as might have been expected, that the amount and consistency of the food have a strong determining influence in the rate of digestion. Fluids escape most rapidly of all. Thus, 7 ounces (200 c.c.) of water have entirely left the stomach in one and a half hours, 2 and tea, coffee, and alcoholic liquors in the same time. Hot drinks, contrary to what might have been expected, did not seem to leave sooner than cold, nor did the quantity of fluid make much difference, so that it scarcely matters, as regards stay in the stomach, whether one takes 3 or 6 ounces of fluid. On the other hand, the presence of solid matter in solution or suspension in the fluid caused it to remain longer, but not much, 7 ounces of boiled milk staying about two hours. Meat-juices, and water containing in solution such substances as peptone, did not remain any longer than ordinary water or milk. Aerated water was found to remain in the stomach for an even shorter time than plain 1 Deut. Archiv.f. Klin. Med., 1893, li. 535. The experiments of Beaumont are of very little value, owing to the fact that they take no account of the amount of food given. 2 The time was always calculated from the moment at which the food had begun to be swallowed. RATE OF DIGESTION 425 waterj probably because the carbonic acid which it contains acceler- ates the stomach movements. As regards solids, digestibility is influenced much more by con- sistence than by amount. 1 An increase in the quantity taken prolongs, it is true, the duration of stay in the stomach, but not proportionally. Doubling the amount eaten, for instance, does not mean doubling the length of time required for digestion. In the case of meat, to take an example, an addition of 50 grammes caused only an increase of one hour in the time required for complete digestion, and in the case of biscuits a similar addition produced an extra delay in the stomach of only seventy minutes. Put otherwise, six times the original quantity of beef requires only three times the original amount of time taken by digestion ; in the case of biscuits, four times the original quantity requires double the time, while with fluids the original quantity can be increased five times while only doubling the original time. The chemical composition of the food, also, is of importance. Carbohydrates, proteids, and fats do not leave the stomach at the same rate. Carbohydrates begin to leave the stomach within ten minutes of their ingestion; they pass out rapidly, and at the end of two hours reach a maximum amount in the small intestine. Fats, on the other hand, remain a long time in the stomach. Their discharge into the small intestine begins slowly, and continues at about the same rate as their absorption or their passage onwards into the large bowel. Proteids remain an even longer time, and their raie of discharge is slower than that of fats. Of animal foods, the most rapidly digested were those of a soft consistence, such as sweetbread. The white meats, e.g., chicken, were more digestible than dark, e.g., duck, or even the red meats, but the method of cooking had great influence on the result. Fresh fish, in his experiments, was more rapidly digested than meat. As regards vegetable foods, the consistency and the amount of solid matter contained were again the ruling factors. Thus, ' mealy ' potatoes were more rapidly disposed of than ' waxy,' and in pur6e more easily than when in pieces. Fine bread and biscuits were found to be more digestible than coarse bread, but there was not much difference between crust, crumb and toast, or even between new and stale bread, provided all were equally well chewed. Cauli- flower was the most rapidly digested of vegetables. The following table contains a summary of these results in greater detail, along with the fuel value of the quantity of each article employed : 1 See Lehmann, ' Ueber die Bedeutung der Zerkleinerung und des Kochens der Speisen £ die Verdauung,' Arch./. Hygiene, 1902, xliii. 123. 4*6 ■FOOD AND DIETETICS TABLE SHOWING RATE OF DIGESTION OF DIFFERENT FOODS AND THEIR CALORIE VALUE. 1 Leave Stomach in 2 to 3 Hours. Calories in Form / Total Food. * Calorie Proteid. Carbohydrates. Fat. Value. 400 c.c. (14J ounces) boiled milk 57'4 788 1376 2738 100 grammes egg, raw, poached, or omelette ( = about two eggs) .. 5i'7 2'I 112-5 1663 100 grammes beef sausage (34 ounces) 597 — 3720 4317 200 ,, sweetbread (7 ounces) 2296 — 04 2300 72 oysters (10 of moderate size) 177 I07 77 351 200 „ white fish (7 ounces) 1796 — 20-5 200 • 1 200 ,, shell-fish , , •• i39'4 — 93 148-7 150 asparagus (5 J ounces) 123 123 — 246 100 ,, white bread (34 ounces ar 1} slices) 213-2 4-6 246-5 100 gramme: 35 3 3079 93 352-5 5o biscuit (if ounces). . 214 1500 214 1928 Leave Stomach in 3 to 4 Hours. Calories in Form oi Total Food. . * Calorie Proteid. Carbohydrates. Fat. Value. 230 grammes chicken (8$ ounces) . 1886 — 856 274-2 250 lean beef (9 ounces) • 215-2 — 348 250- 1 160 „ boiled ham (6 ounces) • 1574 — 5357 6931 100 ,, roast veal (34 ounces) 820 — 13 9 959 100 ,, beefsteak , , • • 1403 — 764 2167 100 „ salted caviare (34 ounces I27'I — 1488 275 9 150 coarse bread (5J ounces) 369 3075 69 351-3 150 <. boiled rice ,, ,, •• i8- 3 4674 4859 150 ., boiled cabbage (5J ounce. >) 185 492 — ■677 Leave Siomaci rN 4 to 5 Hours. Calories in Form of Total Food. j_ Calorie Proteid. Carbohydrates. Fat. Value. 250 grammes smoked tongue (9 ounces) 2470 — 721 968 100 ,, smoked beef (34 ounces) 1107 — I39'5 250-2 250 roast goose (9 ounces) 1640 — 1060 1224 200 ,, salt herring (7 ounces) i54'9 123 3143 4815 150 lentil porridge (54 ounces' 1537 3321 — 4858 200 „ pease porridge (7 ounces) 1886 4264 — 6150 One may compare with these observations those of Verhaegen, 2 who concludes from a large number of experiments that — 4 litre boiled milk leaves the stomach in 24 hours. 1 ,, ,, ,, ,, 34 ,, 100 grammes of bread leave the stomach in 3 , , 150 „ ., .... 4 100 „ ,, and 60 of meat leave the stomach in 4 hours. An ordinary dinner leaves the stomach in 4 to 5 hours. 1 Modified from Strauss, Zeit. f. Didt. Therapie, I900, iii. 198, 279, and based on the results of Penzoldt (Deut. Archiv. f. Klin. Med., 1893, li. 535). 2 'Physiologie et Pathologie de la Secretion Gastrique,' Paris, 1898. ANTISEPTIC ACTION OF STOMACH 4 2 7 Leube 1 divides foods into four groups, according to the ease with which they are digested, the first group containing those which are most digestible : i. Beef-tea, solution of meat (Leube-Rosenthal), milk, soft or raw eggs, Albert biscuits. 2. Boiled calves' brains, sweetbread, boiled fowl, pigeon or calves, feet. 3. Scraped underdone steak, potato puree, stale bread. 4. Roast chicken or pigeon, roast veal, cold roast beef (underdone), white fish, macaroni, rice, chopped spinach. A study of all these results will enable one to select the most suitable foods for persons of weak digestion. 3. Antiseptic Action of the Gastric Juice. — Another function which the stomach serves is that of partially sterilizing the food by the antiseptic action of the hydrochloric acid of the gastric juice. This action, however, is not a powerful one, and some organisms, such as those that form acids, seem to escape it altogether, and there is reason to believe that the same is true of some, at least, of the commoner pathogenic organisms, notably the tubercle bacillus. The sterilizing power of the stomach must vary greatly according to the period of digestion and the nature of the food. It probably reaches its maximum towards the later periods of digestion, when hydrochloric acid is present in the free state, whilst it is much less, or even absent altogether, in the earlier stages, when all the hydro- chloric acid is in a combined form. Food rich in proteid, by fixing the hydrochloric acid, must greatly lessen the germicidal power of the gastric juice. Over the growth of organisms in the intestine the stomach seems powerless to exert any control. Even in cases in which the secretion of hydrochloric acid is entirely arrested, or in which the stomach has been completely removed, no increase in the amount of intestinal putrefaction was found to occur. 2 4. The Temperature of Foods and Drinks. 3 — One of the minor functions of the stomach is that of regulating the temperature of the food. It stands in this matter as a protector of the intestine, which appears to be more injuriously affected by extremes of temperature than the stomach itself. The ideal temperature for food is probably that of the body itself. 1 Zeit.f. Klin. Med., 1883, vi. 189. a See Schlatter, Lancet, 1898, i. 141, and Filippi, Deut. Med. Wochensch., 1894, » See Spath, Archiv. f. Hygiene, 1886, iv. 68, and Uffelmann, Wiener Klinik, 1887, xiii., Heft 9. 428 FOOD AND DIETETICS Cold food is difficult to digest, for it does not excite the stomach sufficiently, nor does it possess the stimulating properties of a hot meal. It has been observed that there is a special craving for alcoholic stimulants- on the part of those who are unable to get hot meals. Extremes of temperature in foods should be avoided as tending to produce local injury to the stomach; from 45° to 130 F. are prob- ably the limits of safety. Drinks at a temperature of 122° F. are sufficient to warm the body, and a temperature of 45° F. is sufficient to cool it. Wunder- lich 1 found that hot punch at 122° F. raised the temperature of the body by o*i° to -03° C. for a period of thirty to sixty minutes, while half a litre of water at the same degree of heat caused an accelera- tion of the pulse by nearly 20 beats per minute very shortly after it had been swallowed. On the other hand, three tumblerfuls of water at a temperature of 45° F. produced a lowering of the axillary temperature from 98*4° F. to 97-7° F., while the pulse-rate fell from 70 to 61 per minute. Violent alternations in the temperature of foods seem to cause Assuring of the enamel of the teeth. Uffelmann, for instance, placed recently-extracted teeth in water first at 65° C, and then directly afterwards at 6° C, and in nine out of eleven cases he produced some degree of splitting of the enamel. The local effects of extremes of temperature in the stomach are very much the same whether the extreme be one of heat or of cold. In each case there is a danger of exciting gastric catarrh. Very hot foods seem to be specially dangerous in stomach-bleedings, e.g., ulcer ; and there are some who say that the special liability of cooks to suffer from gastric ulcer is to be attributed to their constantly tasting very hot foods. On the other hand, very warm fluids may relieve pain in the stomach by abolishing pyloric spasm. The temperature most suited for drinks intended to quench thirst is one of from 50° to 70° F. Ices should be avoided, as they may cause dyspepsia, cardialgia, and even acute dilatation of the stomach, although small quantities of ice undoubtedly tend to allay gastric irritability. It must also be remembered that the drinking of very cold water when one is heated may bring about a reflex congestion of the lungs. 5. Absorptive Power of the Stomach. — The absorptive power of the stomach is surprisingly small. In this also one may see 1 Quoted by Uffelmann. INTESTINAL DIGESTION 429 a provision for the protection of the body, for it allows of the neutralization or rejection of injurious substances before they have time to enter the blood. Alcohol, curiously enough, is of all substances that which the stomach absorbs most readily. This explains to some extent the rapid stimulating action of alcohol. Peptone, sugars and salts, are also absorbed by the stomach to some extent. The stronger the alcohol, or the more concentrated the solution of these substances, the greater is the degree of absorp- tion. There is reason to believe that the process of absorption by the stomach is much more of the nature of a mere physical osmosis than is the case in the intestine, and the process is accompanied by the pouring out of a good deal of secretion. It is in this way, perhaps, that a mixture of alcohol and sugar, such as is found in sweet wines and some malt liquors, may cause ' acidity.' The practical bearings of absorption in the stomach will be more fully dealt with, however, when we come to consider the dietetic treatment of gastric dilatation. Digestion and Absorption in the Intestine. When the food has passed through the pylorus, it enters the duodenum and encounters the secretion of the pancreas. The anatomical disposition of the duodenum seems specially designed to favour complete mixing of the chyme with the pancreatic juice, for the duodenal loop forms a kind of U-tube, in which some delay of the contents may be expected to take place. The degree of disten- sion of this loop seems to have some influence, too, over the opening of the pylorus, so that as long as the duodenum is full no further escape of food from the stomach takes place. The chief stimulant of the pancreatic secretion is the hydrochloric acid, which reaches it from the stomach ; the psychical factor, though active, is not nearly so potent as in the case of gastric secretion. The chemical constituents of the food also have an influence, just as they have in the case of the stomach, fat especially calling forth an abundant secretion. As the pancreatic juice is the chief agent concerned in the digestion of fat, we see in this again a wonderful adaptation of means to ends. Starch, on the other hand, has no great effect beyond that of producing a slight increase in the amount of the sugar-forming ferment. Of the disorders of pancreatic digestion we know but little, though they are probably of less importance than those of the stomach, for the reserve power of the pancreas seems to be so great that it is quite 43° FOOD AND DIETETICS equal to digesting the whole of the food itself should the stomach be unable to perform its share in the process. The importance of this for dyspeptics is very great. As the food passes along the intestine absorption of its ingredients takes place, and the degree to which this occurs in different foods has already been fully considered (p. 10.) The influence of each constituent of the food on the absorption of others is probably of considerable importance, though not much is known about it. The addition of starch to proteid, for example, diminishes the absorption of the latter, whilst fat starvation tends to lessen the absorption of phosphoric acid. 1 On the other hand, if fat is not being well absorbed, as, for example, in cases where the bile cannot enter the duodenum, the destruction of proteids by putre- faction is greatly increased, owing to the unabsorbed fat enclosing the particles of proteid and interfering with their proper digestion. This furnishes an additional reason for interdicting fat in jaundica The increase of intestinal putrefaction brought about in this indirect way no doubt led to the erroneous idea that bile is an antiseptic, feeing that the influence of the carbohydrates is rather to retard the outrefaction of proteids, it is obvious that fats cannot replace the former as far as the intestine is concerned. 2 The role of bacteria in intestinal digestion has sometimes been minimized, at others exaggerated. There is no doubt that they are not indispensable to digestion. On the other hand, they play a useful part in restraining putrefaction. The only bacteria which flourish in the small intestine are those which are capable of forming acids (e.g., acetic, lactic, and succinic) out of carbohydrates. The acids so produced tend constantly to be neutralized by the alkaline secretion of the intestinal mucous membrane, but in the struggle which thus takes place the acids always maintain the upper hand, and consequently the contents of the small intestine have an acid reaction throughout. Thanks to this slight degree of acidity, the growth of putrefactive organisms is restrained, and the destruction of proteids especially prevented. Hence, if one wishes to diminish intestinal putrefaction, the diet must contain plenty of carbohydrates, for it is only out of these that acids can be produced, and but little proteid. 8 This explains the very foetid nature of the stools passed 1 Journal of Experimental Medicine, 1898, iii. 293. 2 See Laas, ' Ueber den Einfluss der Fette auf die Ausnutzung der Eiweisstoffe,' Zeit. /. Physiolog. Chem., 1894, xx - 2 33- ' See Backman, ' Ein Beitrag zur Kenntniss der Darmfaulniss bei Verschie- denen Diatformen unter physiologischen Verhaltnissen, ' Zeit. f. Klin. Med., 1902, xliv. 458. F&CES 43 1 by patients who are being fed exclusively on lean meat. It may be well also to remind the reader again at this point of the value of milk as an intestinal antiseptic (see p. 126). It is important to remember that the contents of the small intestine remain fluid throughout its entire length. Even at the lower end of the ileum the amount of solid matter is only 5 to 10 per cent. The advantages of a fluid diet in intestinal ulceration, therefore, can scarcely be due to any less degree of mechanical irritation on the part of fluid food. In the large intestine the contents of the bowel are brought to a solid form, mainly by the absorption of water. The absorptive power of the large intestine for the nutritive constituents of the food will be considered in another chapter. The investigation of Prausnitz 1 has shown that the faeces are to be regarded as chiefly composed of the remains of the digestive juices, and that their composition is very uniform, the chief ingredients (in the dried form) being Nitrogen 8 to 9 per cent. Ether extract .. .. 12 to 18 „ Mineral matter . . . . 12 to 15 „ The faeces of a mixed diet always contain muscle fibres, but starch is completely absorbed unless pulses or green vegetables are largely eaten. If the diet is of such a nature that much cellulose and some starch are excreted, the percentage of nitrogen falls. If, on the contrary, the absorption of nitrogen is deficient, the percentage of that ingredient rises. Other things being equal, therefore, a low per- centage of nitrogen in the fasces indicates bad general absorption of the food, while a high proportion of nitrogen has a contrary significance. The bulky faces of a vegetable diet are largely due to the presence of an excess of moisture, which has been poured out by the walls of the bowel in the attempt to neutralize organic acids produced by fermentation. In the large intestine, the putrefactive bacteria are able to flourish, for the absorption of carbohydrates higher up renders the further production of acids which restrain putrefaction impossible. The following summary of the digestion of a mixed meal may serve to gajther up a number of the scattered facts which have been mentioned in the preceding paragraphs : The complex sensation called ' hunger ' impels one to seek food. 1 Zeit. f. Biologic, 1897, xxxv. 287. 432 POOD AMD DIETETICS The sight and smell of the food awakens the sensation of ' appetite,' and with it there begins a flow of digestive juices, most marked in the case of the stomach. The soup, which usually forms the first course, by virtue of its warmth and of the gelatin and extractives which it contains, accelerates and increases the secretion of the gastric juice. The solid part of the food is reduced to a pulp in the mouth, and, unless acid substances are mixed with it, part of its starch is changed into sugar. Arrived in the stomach, it encounters the ' psychical ' juice already secreted, the acid of which is imme- diately laid hold of by the proteids of the food. In this way the acidity of the stomach contents is kept down, and the action of the saliva upon the starch is allowed to continue. As the solids become dissolved by the ' psychical ' juice, their chemical constituents are set free, and themselves begin to excite a specific secretion specially fitted for their own digestion. Meanwhile, the acidity of the contents goes on increasing, and soon brings to an end any further action of the saliva upon starch, and kills or paralyzes many of the organisms swallowed with the food, while at the same time the peristaltic movements of the stomach are excited. Under the influence of these the gastric juice and the food are intimately mixed, and the temperature of the mass gradually adjusted to that of the body. As solution proceeds, the semi-fluid part of the contents along with any excess of fluid which has been swallowed finds its way into the pyloric end of the stomach, and by the systolic contractions of the latter is propelled into the duodenum. This process continues for about four or five hours, by the end of which time the stomach is again empty. During all this time the absorption of alcohol and small quantities of peptone, sugar, and salts has been taking place. Arrived in the duodenum, the food encounters the secretion of the pancreas already called out by psychical influences, and now increased by the stimulus of the acidity of the stomach contents and by the specific chemical action of the constituents of the chyme, especially by that of fat. Here digestion is completed, and as the food sweeps along the small intestine its constituents are rapidly absorbed into the blood, or chyle. During this time certain bacteria, which have escaped the action of. the gastric juice, are busy breaking up any carbohydrates which may be present, producing from them organic acids, which restrain the putrefaction of the proteid con- stituents of the food which would otherwise be apt to occur. The fluid poured out by the glands of the small intestine in the. attempt to neutralize these acids more than makes up for any absorption of INFLUENCE OF EXERCISE AND REST 433 water, and causes the contents of the ileum to remain fluid until the large intestine is reached. Beyond this point the production of acids ceases, and the rapid absorption of water causes the contents to assume a solid form, while putrefactive bacteria are able to grow unchecked, save by the products of their own activity. Finally the residue is expelled in the form of faeces, usually about twenty-four hours after the food was first swallowed. The respective influence of exercise and rest on the processes of digestion is disputed. Beaumont, from his observations on St. Martin, came to the conclusion that gentle exercise aided digestion, but the experiments of Fleischer 1 gave a contrary result. The whole question is probably one of blood-supply. Gentle exercise, by increasing the rapidity of the circulation, may aid the secretion of digestive juices and stimulate the movements of the stomach. Severe exercise, on the other hand, by diverting much blood and nervous energy to the muscles, may be expected to have an adverse effect. Sleep is only useful as an aid to digestion in the case of invalids and aged persons, but even in them it may be injurious, probably on account of the depression of the circulation by which it is accompanied. On the whole one can agree with King Chambers, that the best employment after a heavy meal is ' frivolous conversation,' which keeps the heart active without making great demands upon the brain. 1 Berlin. Klin. Wochensch., 1882, xix. 97. £9 [434] CHAPTER XXIV THE PRINCIPLES OF FEEDING IN INFANCY AND CHILDHOOD : HUMAN MILK I. Physiological Requirements in the Diet of Infancy. A healthy infant spends most of its time in sleeping and growing. Its muscular efforts are confined to a little sucking, more or less crying, and some kicking. Hence it follows that the diet of an infant should contain relatively more of the tissue-builders (proteids and mineral matters), and relatively less of the energy-producers (carbohydrates), than one finds in the food of the adult. Like all small animals, too, the infant has a large extent of surface in pro- portion to its bulk ; thus it tends to lose heat rapidly, and requires an abundant supply of the chief body fuel — fat. If these different ingredients be not supplied in due proportion, disorder of health inevitably follows. If the tissue-builders be not sufficiently repre- sented, the muscles, blood, and bones are not properly formed, and the child becomes flabby, pale, and rickety. On the other hand, if the supply of proteid be in excess of the child's digestive and assimi- lative powers, it suffers from disorder of the stomach and bowels. If it be an infant, curdy stools will be passed, and there will be a tendency to diarrhoea. Older children will suffer from indigestion, irritability, and restlessness. A sufficient supply of fat is of even greater importance. Indeed, it may be said that abundance of fat should be the main characteristic of the diet of infancy, just as abundance of carbohydrates is the chief feature of the diet of adult and laborious life. The fat serves as fuel. Without it the child has difficulty in maintaining the proper temperature of its body, and is liable to catarrhs of the lung or bowel. In addition to this great use, fat seems, during the period of rapid growth, to be itself a tissue-producer. The infant is laying down a considerable amount of tissue rich in fat in the marrow of its bones and in its nervous apparatus, and it may well be that the fat of the diet aids in the REQUIREMENTS OF INFANCY 435 production of such tissues. Of this, at any rate, there can be no doubt, that a child whose diet is deficient in fat rapidly loses vigour and is extremely prone to suffer from rickets. The frequent connection between rickets and deficiency of fat in the food is an undeniable clinical fact, of which, however, it is difficult to give a satisfactory explanation. Experiments have been made 1 in which young animals were fed on separated milk practically free from fat ; but although the absorption of phosphoric acid by them was found for some reason or another to be much interfered with, yet they did not suffer from rickets. Important though an abundant supply of fat is, one must take care not to give it in excess, for under these circumstances it is a frequent cause of vomiting and diarrhoea. A milk which contains more than 6£ per cent, of fat may always be expected to produce these results. Carbohydrates are, as we have seen, not of so much importance in the dietary of infancy as in that of older children or the aduli. They are important, however, not only as making provisiou for what muscular effort the child does display, but also in. their capacity as proteid-sparers (p. 22). If there be a due supply of sugar in the diet, it is reasonable to suppose that less proteid will suffice. The carbohydrates, however, are the ingredient of the diet which is least likely to be represented in too small amount. On the contrary, there is a much greater danger of supplying them in excess, or of making them a substitute for fat. An infant which is the victim of such an error may be plump enough, but its muscles are flabby, its skin pale, and its bones often rickety. It is the false appearance of good nutrition which such infants often possess that is apt to deceive the uninitiated, and such children have been known to receive prizes at baby-shows, when all the time they were undoubtedly the subjects of rickets. It must be remembered, too, that carbohydrates, especially when given in excess and in unsuit- able forms, such as starch or cane-sugar, are very prone to undergo fermentation in the stomach and intestine of the infant, whereby acids are produced and griping and diarrhoea result. The mineral ingredients of the food in infancy are equal in importance to the proteids. Like these, they are concerned in building up the child's body, and deficiency of them will produce much the same symptoms as deficiency of proteids. Salts of lime, potash, and phosphoric acid are specially important. Phosphate of lime is wanted for the bones, and phosphate of potash for the muscles and blood. It must not be supposed that it is a matter 1 Journal of Experimental Meiicine, 1898, iii. 293. 28—2 436 FOOD AND DIETETICS of indifference in what form these are supplied. It would seem that these salts are of much greater use when they enter the body in combination with organic matter than they are in a free mineral form. Milk, and especially human milk, is peculiarly rich in organic combinations of these salts, and for this reason lime-water or chemical preparations of salts can be no proper substitute for it. On the other hand, there is no reason to believe that the presence of an excessive quantity of mineral matter in the food of an infant does any harm ; the child simply does not absorb or assimilate more of each com pound than it requires for building or other purposes. The importance of water to the infant will be evident when one recollects that more than three-fourths of the whole body consists of it, and that it constitutes about four-fifths of milk, which is the natural diet of infancy. Water has also local uses in the stomach and bowels, promoting as it does the processes of absorption and secretion. One is too apt to forget that an infant may suffer from thirst as well as from hunger, and that water will allay the former better than milk. The effect of a drink of cold water is certainly always worth trying if a child is suffering from evident but un- explained discomfort. 2. Human Milk: its Composition and Variations. We have spoken on the one hand of the importance of a due supply of each nutritive ingredient in the diet of the infant, and on the other of the danger to health which results if any one of them be present in excess. One naturally turns to human milk, the natural food of infants, for guidance as to the proper quantity of each ingredient to be supplied, and for this reason the study of its exact chemical composition is of the first importance. On sur- veying the records of the chemical analyses 1 of human milk which have been made, one is struck both by the enormous amount of work which has been done on the subject, and at the same time by the discrepancies in the results of different observers. These dis- crepancies are to be explained partly by technical difficulties in milk analysis, and partly by the fact that the milk of one woman may differ not only from that of another, but may also show variations from day to day and at different periods of nursing. 2 1 For a review of analyses of human milk, see Blauberg, ' Experimentelle und Kritische Studien iiber Sauglingsfaces, ' Berlin, 1897, an d Hauser, Fortschr. der Med., 1897, xv. 929. 2 Konrad Gregor (Volkmann's Samml., 1901, M. 88, N.F., No. 302) finds that the fat is a particularly variable ingredient of human milk, the amount of it fluctuating from day to day and from hour to hour. This shows the futility of basing con- clusions upon the result of the examination of a single sample of milk. COMPOSITION OF HUMAN MILK 431 The following 1 represents the results of analyses of human milk, taken about the middle of the second week of nursing : Specific gravity . . 1032 Water 8775 per cent. Solids . . . . . . 12 '25 ,, Proteid . . . . 1-62 , , F * 3-14 .. Milk-sugar Mineral matter Citric acid Unknown extractives Reaction 6-26 per cent. 027 o - o5 o - gi Alkaline. A healthy woman produces 700 to 2,000 grammes (i£ to 4 pints) of such milk daily, although the former figure would be much nearer the average than the latter. I should like to direct special attention to two points in the above analysis : First, to the small amount of proteid which human milk contains, and, secondly, to the presence of a considerable proportion of ' extractive ' matters. These are admittedly of unknown nature, but they contain nitrogen. 2 The earlier analysts classed them amongst the proteids, and hence overstated the amount of the latter which human milk contains. Furthermore, the above analysis must only be taken as representing the average composition of human milk. Considerable variations are met with, the causes of which may be considered under the following heads : 1. Variations dependent on the Period of Suckling. — One might naturally expect that an infant a few days old would not require the different ingredients of milk in exactly the same relative pro- portions as one of some weeks, and chemical analysis of milk at different periods of lactation verifies the expectation. The milk secreted during the first two or three days after the birth of the child is called colostrum, and has some peculiar characters. It is more watery-looking than ordinary milk, and contains a special form of proteid, which causes it to clot on boiling for the first day or two. The actual amount of proteid which it contains is greater than in ordinary milk, though the exact figures given by different analysts vary on the point, some placing the amount of proteid as high as 8 per cent. The following table contains the average of a number of samples of colostrum analyzed by Woodward : 3 1 Analysis by Camerer and Soldner, Zeit. f. Biolog. , 1896, xxxiii. 535. 2 According to kietschel (Abst. in Maly's Jahrbuch Thier-Chemie, 1506, xxxvi. 259), about 80 per cent, of the non-proteid nitrogen of human milk is contained in urea, the rest being present in peptides and peptoids. * Journal of Experimental Medicine, 1897, ii. 217. 43« FOOD AND DIETETICS Proteid rg per cent Fat 4'° Sugar .. C-s „ Mineral matter .. o-z „ Specific gravity . . 1024 to 1034 (variations due to differences in the amount of fat) Water 875 per cent. Colostrum may contain a number of peculiar microscopic cells called colostrum corpuscles, the number of which is very variable. As they consist of proteid, they must be of some nutritive value to the child. One of the uses of colostrum appears to be as a laxative, causing the expulsion from the intestine of the child of a quantity of waste matter with which it comes into the world. After the third day the ordinary milk begins to be produced, and the changes which it undergoes in composition from this period onwards are exhibited in the following table : INFLUENCE OF PERIOD OF LACTATION ON COMPOSITION OF HUMAN MILK. 1 Increase in Period. Total N. Proteid. Fat. Sugar. Ash. Child's Weight per Day. 35 to 40 grammes 5th day 0'33 20 28 54 034 8th to nth day 027 16 31 62 027 20th „ 40th „ 0'20 II 3-8 64 022 70th ,, 120th ,, OT7 10 29 67 020 170th and after OI4 08 26 68 019 22 18 ., A study of it will show that on the whole the building material (proteid and mineral matter) tends to become less in amount as lactation proceeds, the sugar rises rapidly up to the end of the second week, and after that more slowly, while the fat, after reaching a maximum about the second month, tends to fall off again in the later periods. A little consideration will show that these variations are very much what one would expect from the physiological requirements of the infant at different ages. During the first few weeks of life the child grows much faster than subsequently. The last column of the table shows that in the first month from 35 to 40 grammes are added to the weight each day, while by the time the sixth month is reached the daily increase in weight has fallen to 18 grammes. Obviously, then, the infant will require relatively more building material at the former period than at the latter. The gradual increase in the proportion of carbohydrate is also just what one would expect in view of the daily increasing muscular activity of the child. A general consideration of the table clearly shows that the milk of 1 From analyses by Camerer and Soldner, Zeit. f. Biolog., 1896, xxxiii. 43, 535 ; increases in weight from Proscher, Zeit. f. Physiolog. Chcm., 1897, xxiv. 285. Reyher, however (Abst. in Maly's Jahrbuch Thier-Chemie, 1906, xxxv. 308), took mixed samples of the milk before and after nursing, and found that between the 115th and 187th days it contained from 4-28 to 498 per cent, of fat, whilst between the 208th and 225th days, when secretion began to fail, the percentage was from 4^9 to 5 - g8. VARIATIONS IN HUMAN MILK 439 the mother certainly does not get richer as the child gets older, but that the increasing demand for nutriment by the growing infant is met by supplying an increased quantity of milk, and not by providing an improved quality. This fact should be noted by those who have to provide artificial substitutes for human milk. It follows, also, that there is some scientific justification for the popular view that a wet-nurse should not suckle a child which is much younger than her own. The difference, however, between the composition of milk at the third week and third month is not sufficiently great to make such a difference between the ages of the two infants a bar to the employ- ment of the nurse. 1 2. Variations dependent on Individual Differences in the Mother or her Child. — These are of comparatively little importance. It has been found that the milk of any given woman will show greater varia- tions from day to day than the milk of different women on any one day. Weak women, also, seem to furnish as good a milk as those who are robust and strong, and the milk of women who have borne many children is but little poorer than that of those who are nursing their first infant. Age, also, has little influence, for the milk of women approaching the climacteric has not been found inferior to that of mothers hardly out of their teens. Illness, menstruation, pregnancy, fever, and even severe emotional disturbance, are also almost entirely devoid of any appreciable effect on the composition of the milk. The most striking fact about the composition of the milk, indeed, is its independence of outside influences. 2 The fact that a woman has a feeble child is no proof that the milk is at fault. On the contrary, it was found that the milk of women with feeble infants was rather richer than when the suckling was robust. It would almost seem as if there was here a provision of Nature to supply the child which has only strength to draw a small quantity of milk with a food of proportionately better quality. 1 See also Baumm and Illner, Samml. Klin. Vortrage (Gyndh.), 1894, N f:> I0 5. 41. These observers found considerably less difference in the composition of the milk at different periods than was shown in the later work of Camerer and Soldner. Monti (Wiener Klinik, 1897, Jahrg. xxiii., Hft. 1, 2, 3), says that a child from one to six weeks old should have a wet-nurse whose child is not more than two months. A child from two to four months requires a nurse who has not been suckling for more than three to four months. Whether for older babies a younger nurse is admissible depends on the age of the child. A nurse whose own infant is two to three months old will do for a child of six to eight months, but for a three- months child the first milk is often insufficient. 2 See Baumm and Illner (loc. cit.), on whose careful observations and analyses most of the above statements are based. 44° FOOD AND DIETETICS 3. Influence of the Mother's Diet on the Composition of her Milk.— Careful observations on this important subject were made by the authors already quoted (Baumm and Illner). They fed various nursing women on the following dietSj and analyzed the milk produced on them : 1. An ordinary mixed diet taken in great abundance. 2. A highly nitrogenous diet — i.e., one containing much cheese, eggs and meat. 3. A diet rich in carbohydrates and fat, but poor in nitrogen — i.e., plenty of bread, farinaceous foods, sugar and batter. 4. A very fluid diet. 5. An ordinary diet plus 2 to 3 pints of lager beer daily. 6. A diet consisting largely of salt fish, pickles, and other salt foods. They found that, in the main, fat was the only ingredient of the milk on which the diet produced any appreciable effect. It was increased, sometimes rising 1 per cent., on the first and second diets only. An abundant supply of carbohydrates had no influence upon the amount of fat. Nor, curiously enough, had the amount of fat consumed in the food ; indeed, an increased amount of fat eaten seems to diminish rather than increase the amount of cream in the milk. These results are in harmony with those obtained in the feeding of cows, where a bean diet produces more and richer milk than any other, and the amount of fat in the food is without effect. 1 It is surprising, too, that an increased amount of fluid in the diet does not appreciably increase the total yield of milk. Nor did the diet of salted foods affect the composition of the milk or the health of the child. On the whole, the results of these and of similar experiments 2 tend to show that the composition of the milk yielded is to a large extent independent of the diet, just as we have seen it to be of other external conditions. Even if the supply of food is to a large extent cut off, the mother goes on producing milk just as before, only at the expense of her own tissues. Thus, it was found that during the siege of Paris women were able to continue nursing although almost starved to death. The influence of alcohol on the secretion and composition of milk is a subject of great practical importance.' The experiments just quoted showed that 2 to 3 pints of light 1 Thomson, ' Food of Animals,' London, 1846, p. 132. 8 See Temesvary (Monatsheft f. Get. u. Gynah., November, 1900). 3 For an elaborate resume of our knowledge on this subject, see Rosemann, Archiv. f. die Ges. Physiolog., 1900, texviii. 466. INFLUENCE OF MOTHER'S DIET 44 1 beer daily had no effect on the composition of the milk, and other observers have shown that as much as five glasses of port or cham- pagne are similarly devoid of influence. 1 Physiologically alcohol may be regarded as the nutritive equivalent of a certain amount of fat (p. 340), and as fat in the diet is without favourable influence on the composition of the milk, so, too, is alcohol. The common prescription of stout for nursing mothers is thus devoid of scientific justification, for the nutritive ingredients of stout are its alcohol and a certain proportion of sugar, and both of these are unable to improve the quality of the milk. On the other hand, the bad effects on the child, which have been attributed to the taking of alcohol by the mother, are equally imaginary, the fear that alcohol will be excreted by the milk being groundless, unless, indeed, the mother indulge in it to the extent of producing intoxication. Distillation of the milk in the above experiments failed to show the presence of any alcohol in it at all. Alcoholic liquors, then, cannot directly affect the quality of the milk. On the other hand, if a little bitter beer or a glass of wine at meals increases the mother's appetite and her power of digesting ordinary food, then such an addition to her diet will improve her own nutrition and with it the composition of her milk. Seeing that the composition of the milk is so little affected by diet, one need not jump to the conclusion that if a suckling is suffering from dyspepsia there is some error in the mother's food. So long as the proportion of fat in the milk remains normal, it may be assumed that there is no great fault in the dietary of the mother. On the other hand, if the milk shows a deficiency of fat, the best way to improve its quality is to increase the appetite of the mother for ordinary food, to supply her with that abundantly, and of an easily-digested quality, to let her have four meals daily, and to see that meat or some other form of proteid food is well represented in at least three of them. 4. Influence of Frequency of Suckling on the Composition of the Milk. — The act of suckling serves as a stimulus to the breast, and if repeated at too short intervals the richness of the milk is increased, and it may become less digestible. Hence, if a child is crying from indigestion, an attempt to quieten it by frequently giving it the breast is sure to lead in the end to the production of an even less digestible milk, and so to an aggravation of the trouble. 1 Klingemann, quoted by Cautley. 442 FOOD AND DIETETICS 3. Amount of Milk required by the Child daily. One can only arrive indirectly at the amount of milk which a child should get at each meal and in the course of the day. Argu- ments from the size of the stomach in infancy are not of much value, for individual variations in the size of the stomach are very wide, and the size after death is no certain criterion of the capacity during life. Nor is the amount of milk in the breast a certain guide, for the child need not exhaust the breast at each meal. A method which has been widely adopted is that of carefully weighing the child before and after each feed. If carried out on a sufficiently large number of infants, this method affords a fairly trustworthy basis from which to arrive at the average quantities required at each age, and it is by such a method that the following tables have been constructed. AMOUNT OF MILK REQUIRED DAILY (CAMERER). _ . , Quantity in Twenty- rmoa - four Hours. 1st day 30 grammes. 2nd 130 ,, 3rd 240 4' h 290 5* 33° 6th 365 7th „ .. .. .. .. .. 400 ,, Middle of 2nd week .. .. .. 450 ,, End ,, „ .. .. .. 500 ,, 3rd week . . . . . . . . 497 „ 4th 582 5* 653 6th 734 7th ,, 780 ,, 8th 803 9th 817 10th 850 ,, nth 764 „ 12th 767 ,, 13th 819 14th ,, 829 ,, 15th 838 16th 843 17th 851 18th 875 I9th 872 m 20th 820 ,, 2ISt ,, .. .. .. .. .. 862 „ 22nd 848 „ AMOUNT OF MILK REQUIRED DAILY 443 AMOUNT OF MILK REQUIRED DAILY— AVERAGE MEALS (FEER).i Period. Quantity. Per Day. ist week 40 to 50 grammes. 291 grammes. 2nd „ 80 ,, 90 „ 549 3rd to 4th week 8 5 .. no 590 to 652 5th „ 8th .. 120 .. 135 687 ,, 804 gth * 12th „ 140 815 „ 828 , 13th „ 16th „ 150 852 ,,893 , 17th „ 20th „ 155 902 .,947 , 2ISt .. 24th ,, 160 „ 956 ,,980 , • AVERAGE MEALS IN ELEVEN BOTTLE-FED BABIES (SCHMID-MONNARD). 2 Period. Quantity taken at Each Meal. ist to 4th week 5th , 8th gth , 12th 13th , 16th 17th , 20th 2ISt . 24th 25th , 28th 29th , , 32nd 33rd , ^6th 37th , 40th 4ISt ,44th 185 c.c. 215 .. 230 .. 260 ,, 270 ,. 270 „ 290 „ 330 .. 380 .. 310 „ 350 .. The last observer found that the quantity taken at a meal usually surpasses the capacity of the stomach, the explanation of which probably is that the stomach begins to empty itself before the meal is finished. 3 Obviously these data must only be regarded as affording average indications. They must not be applied too absolutely to any given child, for small and weakly children will necessarily require less nutriment than those which are heavy and strong, and healthy infants of a few weeks may take as much milk as feebler ones whose age is counted by months. Bearing these precautions in mind, then, one may say that on an average a healthy infant will require — During ist to 4th week . ,, 2nd ,, 4th month „ 5th ,, 7th „ 600 grammes milk daily. 800 95° The child will require eight meals in the twenty-four hours ; there- fore a wet-nurse should yield from each breast two or three hours after the last suckling — In ist to 4th week 40 grammes. . „ 2nd,, 4th month 55 ,, „ 5th „ 7th „ 65 1 Quoted by Hauser, Fortschr. der Med., 1897, xv. 929. 2 Jahrb.f. Kinderheilh., 1899, xlix. 67. 8 See also Feer, ibid., 1906, lxiv. 355, and Mosenthal, Arch, of Pediatrics, 1909, Jfxvi. 761, 444 FOOD AND DIETETICS The importance of regularity in the feeding'of infants cannot be exaggerated. By proper timing of the meals it can be arranged that the stomach shall have plenty of time to empty itself, and thus one cause of indigestion will be avoided. The child is a creature of habit, and if it be trained to regular feeding hours will not expect feeds between meals. The following table, borrowed from Holt, represents in a convenient form the best intervals for feeding at different ages, and (approximately) the amount of drink to be taken at each meal. 1 The table is constructed in order to afford guidance as to the quantities to be given in artificial feeding, but the same time intervals should be observed when the child is being fed by the breast, although in that case the quantity taken can usually be safely left to be determined by the appetite of the child. SCHEDULE FOR FEEDING HEALTHY INFANTS DURING THE FIRST YEAR. .E => ■3.8 c •3 1 V a O . 1- Wl *l fe h V ^ «2 c >>t. Age. . 3 "3.2 V ^'"S .t: s bb >J2 .SE c 6 * 3 5* -2 « S » 3 ,* V V I s .Sfd flj s a Hours. Ounces. Grammes. Ounces. Grammes. 3rd to 7th day 10 2 2 1-14 30-45 10-15 310-460 2nd and 3rd weeks 10 2 2 ii-3 45-90 I5-30 460-930 4th and 5th weeks 9 2 I 2j-3i 75-uo 22-32 680-990 6th week to 3rd month 8 2i I 3-44 90-140 24-36 740-1,110 3rd to 5th month 7 3 I 4-54 125-170 28-38 870-1 ,080 5th to 9th month 6 3 O 54-7 170-220 33-42 1,020-1,300 9th to 12th month S 3i 74-9 235-280 37-45 1,150-1,400 As in the previous tables, the quantities in this case must again be regarded as only applicable to the healthy child of average weight, and may require to be reduced somewhat for delicate infants. There are two criteria by which one can judge whether the amount given is sufficient : (1) the weight of the child, (2) the character of the stools. Regular weighing is of the greatest importance, and if a 1 Such a table must be used with some elasticity. In very delicate infants it may be necessary to feed at even shorter intervals, whilst in those which are healthy it is often possible to feed at four-hourly periods quite early. FOOD VALUE OF HUMAN MILK 445 steady increase in weight be not manifest, there is something wrong with the diet. Inspection of the stools will show whether they contain any undigested milk, and so whether absence of increase in weight be due to deficiency in the amount of the diet or to some defect in its quality. 4. Digestibility of Human Milk. Stomach digestion is- not of much importance in infancy. The stomach in early life is small in capacity and of but feeble muscular power, and seems to allow the food introduced into it to pass quickly on into the intestine, where the essential work of digestion takes place. Thus, it has been found, 1 by washing out the stomachs of infants at varying intervals after feeding, that, if 3 ounces of milk be taken at a meal, fully three-fourths of it has left the stomach after the lapse of two hours, and that in another twenty or thirty minutes the stomach is entirely empty. Whether the milk really clots in the stomach in very early life is disputed, some writers contending that there is no rennet to be found in the stomach during the first month. Whether this be so or not is not of much importance, for the clot formed by human milk is, for reasons to be explained later (p. 451), very much looser than the clot formed by cow's milk, and does not offer any serious difficulty to the stomach in its digestion. The absorption of the constituents of human milk in the intestine of infants seems to be very complete. Proteid is said 2 to be absorbed to the extent of 99 per cent., fat to 97 per cent., and the mineral salts to 90 per cent., while the sugar enters the blood in its entirety. During the first week or so of life, however, the absorption of the fat of the milk does not seem to be always as perfect as these figures would indicate, and a good deal of fat may be found in the motions. 3 It would seem, indeed, as if the newly-born infant required a little practice before it is able thoroughly to digest even its mother's milk. 5. Nutritive Value of Human Milk. Comparing the nutritive value of a given amount of human milk with that of an equal quantity of cow's milk, one may say that the two yield practically the same amount of solid nutriment ; but the fuel value of the cow's milk is rather greater than that of human 1 Van Puteren (Diss. St. Petersburg, 1889), reference in Jahrb. f. Kinierheilh., 1890, xxxi. 188. a Uffelmann, Deut. Archiv.f. Klin. Med., 1881, xxviii. 437. 8 See Blauberg, ' Studien iiber Sauglingsiaces, ' Berlin, 1897. 446 FOOD AND DIETETICS milk, owing to the larger amount of fat which it contains. The difference, however, is not great, for 100 grammes of cow's milk yield 66 Calories, and a similar quantity of human milk 62J Calories. Both in building material and in fuel value, therefore, human milk is a poorer fluid than the milk of the cow. 1 An ordinary infant, six months of age, consuming the usual amount of breast-milk, will get from it, roughly speaking, the following amounts of nutritive materials : Proteid .. .. .. .. 14 grammes. Fat 30 Carbohydrates . . . . • • 59 , . These quantities may be compared with the standard for an ordinary man doing moderate work thus : Adult at Moderate Infant of Work ( Voit). Six Months. (Weight (Weight = 70 Kilos.) =67 Kilos.) Proteid .. .. 118 14 Fat 56 30 Carbohydrate .. 500 59 Calories .. .. 3,054 578 This comparison is also exhibited in a graphic form in Fig. 33. One is at once struck by the relatively large amount of fat which the diet of human milk contains. The infant of six months actually obtains more than half as much of that constituent as the full- grown man. The relation of proteid to carbohydrate in the two diets is very similar, but it must be remembered that the man is doing muscular work, while the infant is not. Relatively to weight and mode of life, therefore, the infant is much more abundantly nourished than the adult. 2 It will be seen, too, that a nursing mother yields up about one- eighth of the proteid and carbohydrate in her ,diet to her child, and fully one-half of the fat, whilst more than one-fifth of the fuel value 1 The direct observations of Rubner show that 1 litre of human milk yielded in one instance 6142 Calories, and in another 723-9. A similar quantity of cow's milk yields 6go'4. In other words, an average sample of either human or cow's milk may be expected to yield close on 700 Calories per litre. Under the most favourable conditions in the adult, only 90 per cent, of this is available, owing to defective absorption, whereas in the infant, in which the digestion of milk is more perfect, 91 to 91 6 per cent, is available. 2 The surface of the child is relatively three times as great as that of the adult. The following table (from Camerer) shows the relation between extent of surface and the Calories supplied in the diet at different periods of life : Infants. Age in weeks 2 7 14 20 59 Weight in kilos 3 42 53 63 10-3 Calories per square metre of surface 1,020 1,420 1,330 1,270 1,390 INFANT AND ADULT DIET CONTRASTED 447 of her food is also handed over to the infant. The chemical energy which a mother expends daily, therefore, in nursing an infant six months of age would be sufficient to raise a ton weight about 800 3054 0ALORIE9 CARBOHYDRATE. FAT. IT56 PROTEID. 678 CALORIC* Fig. 33. promp ts:! 4a -Comparison of Nutritive Constituents required by an Adult and by an Infant of Six Months. feet high, or more than twice as high as the top of the dome of St. Paul's. 1 Age in years Weight in kilos Calories per square metre of surface Boys. 3 to 5 18 1,680 7 to 10 24 1,440 11 to 14 34 1.250 65 s kilos. 1,190 1,420 15 to 16 52 .. 58 I.220 Adults. Weight Calories (rest) , , (work) Immediately after birth, therefore, a. child gets a smaller supply of Calories Der square metre than an adult, and consequently loses in weight, but later on it sets more per surface area, and is thus able to grow. ' This, of course, is assuming that the whole potential energy of the milk could be converted into work. [448] CHAPTER XXV THE PRINCIPLES OF FEEDING IN INFANCY AND CHILDHOOD {continued) : SUBSTITUTES FOE HUMAN MILK In the last chapter we learnt that the physiological peculiarities of infancy demand that the diet during that period of life should be relatively rich in proteid and mineral matter, and especially so in fat. A consideration of the chemical composition of human milk showed how well adapted it is to meet these demands, while a com- putation of the amount of it which infants consume at different ages enabled us to form some idea of the quantity of each nutritive ingredient actually required at each period of infancy. Further investigation taught us that human milk is easily disposed of by the infant's stomach, is absorbed very completely in the intestine, and is a fluid of high nutritive value, and therefore eminently adapted for the requirements of the child. These results of scientific investigation have been long anticipated by experience, and both unite to emphasize the inestimable value to the infant during the first ten months at least of its life of a dietary of human milk. Unfortunately, however, the mother is often unable or unwilling to suckle her infant, and one has to find some substitute for the natural supply. A wet-nurse is, of course, from the infant's point of view, the best alternative, but one need hardly say that this mode of feeding is open to considerable practical disadvantages. One naturally looks next to the milk of other animals. The following table exhibits the approximate composition of the milk of some of the commoner domestic animals compared with that of human milk : roteid. Fat. Sugar. Ask. Other Nitrogenous and Unknown Bodies o'9 352 6-75 019 06 30 355 45i 070 °'3 28 34° 380 o-95 — 19 1 00 633 045 049 1-6 093 560 036 — MILK OF DOMESTIC ANIMALS 449 COMPOSITION OF THE MILK OF DIFFERENT ANIMALS. 1 100 Grammes Milk contain in Grammes Human Cow Goat Mare Ass It will be observed that none of these is identical with human milk. This is not surprising, for the composition of a milk, especially as regards its proteids and mineral constituents, seems to depend upon the rate of growth of the animal for which it is intended. The faster a young animal grows, the richer is the mother's milk in these two ingredients. This fact is brought out very strikingly in the following table : 2 Time by which 100 Parts Milk contain Weight is Doubled. Proteid. Ash. Lime. Pho sphoric Acid. Human . 180 days 10 0'2 0-032 0047 Horse 60 ,, 2-0 0-4 0124 0-131 Calf .. 47 .. 35 07 0160 0197 Goat . . 19 .. 43 o-8 0210 0-322 Pig -• 18 „ 59 — — — Sheep 10 „ 65 09 0-272 0-412 Cat .. 94 .. 70 10 — — Dog .. 8 „ 73 13 Q-453 o-493 Rabbit 7 .. 104 24 0891 0996 The milk of the ass has often been stated to be the closest approximation to mother's milk. I have collected the results of all the most recent analyses of it, and compared them with the standard of composition of human milk as follows : Ass's Milk Ellenbereer's Avtrtt S e °f (Schlossmann' s . , f. other Human Milk. 3 Analysis).* Analysis. Ana i yses * Water .. .. 8880 — 90-5 87-60 Proteid .. .. 1-30 1*2 to 1*7 1-9 1-52 Fat 0-36 01 ,, 17 1 '4 3-28 Sugar .. .. 4-94 5 „ 6 6-3 6-50 Mineral matter .. 0-309 03 ,, 0*4 0-4 027 It will be observed that ass's milk is poorer in every ingredient except, perhaps, proteid and mineral matter. It is especially poor in fat, which is so important to the infant. In addition to this it is 1 Heubner, ' Ueber Milch und Milchpraparate, ' Zeit. f. Didt. und Physik. Therapie, 1899, iii. 1. 1 Heubner, Zeit. f, Didt. und Physik. Therapie, 1899, iii. 1. * Schlossmann, Zeit.f. Physiolog. Chem., 1897, xxiii. 258. * Dujardin Beaumetz, Wynter Blyth, Peligot, Cheadle. » Camerer and Soldner, lot. cit. 29 45o FOOD AND DIETETICS stated to be slightly laxative in its effects, and contains relatively more casein and less albumin than human milk, but it resembles the latter in leaving no residue of nuclein or paranuclein on digestion and in having an alkaline reaction. It is expensive also, and difficult to obtain, although one at least of the large London dairy companies now keeps a stock of milch asses for the purpose of supply- ing it. 1 On the whole, it cannot be said to be in any way superior to the modifications of cow's milk which will be dealt with later. The same remarks are applicable to mare's milk as to ass's, except that the former is richer in sugar. Goat's milk is a com- paratively strong milk and not any better suited for use in infancy than cow's. In the vast majority of cases, then, cow's milk must be the substitute, and hence a careful study of the differences, chemical and physiological, between it and human milk is a matter of the first importance. Chemical Differences between Human and Cow's Milk. (a) Quantitative Differences. — Taking the average results of a great number of observations on the general chemical composition of the two milks, one may compare them thus : Water .. Proteid.. Fat Sugar Mineral matter Reaction Human Milk. Cow's Milk. 87 to 88 per cent. 87 to 88 per cent 1 .. 2 3 „ 4 „ 3 .. 4 .. 34.. 4l .. 6 »■ 7 .. 4 .. 5 „ O'l „ - 2 „ 07 „ Alkaline. Acid. One sees that while the total amount of solids in the two kinds of milk is about the same, yet the relative proportions of the different constituents in the two cases are very different. Cow's milk is the richer in proteid, mineral matter, and (to a less degree) in fat ; human milk excels in sugar. The superiority of cow's milk in the building materials is no doubt due to the more rapid rate of growth of the calf than of the infant, but the excess of carbohydrate in human milk is rather surprising when one compares the relative muscular activities of the calf and the baby. It suggests that some of the sugar in human milk is intended as a weak form of fuel instead of the more powerful heat-producing fat, and this substitution may be due to human milk having been devised as an infant food 1 Asses very rarely suffer from tuberculosis, so that the use of their milk is to some extent a safeguard against that disease. HUMAN VERSUS COW'S MILK 451 suited to a warmer climate than ihat which civilized man now occupies. The proportion of lecithin is also relatively much greater in human than in cow's milk, there being 3*05 parts of lecithin to every 100 parts of proteid in the former, and only 1*40 to 100 of proteid in the latter. This is probably to be attributed to the relatively greater weight of the brain in the child than in the calf. 1 (b) Qualitative Differences. — On more closely examining cow's milk, one finds that the differences in kind between its principal ingredients and those of human milk are even greater than the differences in the relative amounts. Sugar, indeed, is the only ingredient which is identical in kind in the two milks ; the nitrogenous matters, the fat and the mineral salts must be compared separately in each. 1. Nitrogenous Matters. — We have already seen that human milk includes a considerable proportion of unknown ' extractive ' bodies which contain nitrogen. Cow's milk contains considerably less of these. One-eleventh of the total nitrogen in human milk is present in the form of extractives, as compared with one-sixteenth in cow's milk. 2 As to the uses of these extractives to the child we are entirely in the dark, but it conceivable that too low a proportion of them in the diet may not be free from disadvantages. The proteids of milk are of two kinds, casein and albumin (Chapter VII.). Cow's milk contains relatively much more of the former, and human milk of the latter. The exact proportions given by different analysts vary considerably, but a reliable estimate has given 4 parts of casein to 1 of albumin in cow's milk, and the proportions of the two in human milk as equal. 3 When one remembers that albumin is a much more easily' digested form of proteid than casein, it is evident that there is here an important practical difference between the two milks. Not only so : the casein itself is actually different in the two forms of milk. Cow's casein leaves behind an indigestible residue (paranuclein) ; human casein does not. 4 When an acid is added to cow's milk the casein is thrown down in large flocculi, which do not readily dissolve in excess ; under similar treatment human milk yields very fine flocculi which readily go into solution on adding more acid. Lastly, 1 Burow, ' Der Lecithingehalt der Milch und seine Abbangingkeit vom rela- tiven Hirngewicht des Sauglings,' Zeit. f. Physiolog. Chemie, 1900, xxx. 495. 8 See Munk, Virchow's Archiv., 1893, cxxxiv. 501 ; and Camerer and Soldner, Zeit. f. Biolog., 535, 1896. 3 Hammarsten, Jahres-Ber. f. Thier-Chemie, 1895, p. 206. For other estimates see Edlefsen, Munch. Med. Woch., xlviii. 7, 901 ; and Van Slyke, New York Med. Journ., May 25; 1907. 4 Szontagh, Ungar. Archiv. f. Med., 1894 (reference in Jahres-Ber. f. Thier-Chemie, 1894, xxiv. 209). 29 — 2 452 FOOD AND DIETETICS human casein is richer in sulphur than the casein of cow's milk. For these reasons human casein is more easily digested. 2. Fat. — The fat of human milk contains more oleic acid, and has consequently a lower melting-point and is more easily digested than the fat in cow's milk. This greater digestibility of the fat of human milk is increased by the fact that it is present in a much finer state of division than the fat droplets in cow's milk. Human milk fat contains also much less of the soluble or volatile fatty acids than one finds in the fat of cow's milk 1 ; the exact significance of this is, however, unknown. 3. The mineral salts in the two forms of milk also show important differences. Not only are calcium and phosphorus both present in much smaller amount in human milk, but there are important differences in the form in which the phosphorus occurs in the two cases. In human milk there is only, or almost only, organically combined phosphorus present ; in cow's milk less than half is in this form of combination. 2 In its high proportion of organic phosphorus human milk recalls the chemical peculiarities of plant embryos or the yolk of egg. Considering the great importance of phosphorus in the nutrition of the infant, and the fact that organic combinations of it are probably more easily assimilated than its inorganic salts, one must admit that the differences between human and cow's milk just pointed out are not to be lightly disregarded. In the light of these facts, regarding the profound qualitative differences in chemical composition between human and cow's milk, one must conclude that it is impossible ever so to modify the latter that it shall be identical with the former. In other words, a truly ' humanized ' cow's milk is a chemical impossibility. Comparative Digestibility of Cow's and Human Milk. It is a familiar fact that most young infants have much greater difficulty in digesting cow's milk than that of their own mother. 1 Laves, Zeit./. Physiol. Chem., 1894, xix. 369, and Ruppel, Zeit. f. Biol., 1895, xxxi. 1. 2 Of the total phosphoric acid in human milk, 35 per cent, is in the form of lecithin. Of the total phosphoric acid in cow's milk, 5 per cent, is in the form of lecithin. Of the total phosphoric acid in human milk, 41 per cent, is in the form of phosphocarnic acid. Of the total phosphoric acid in cow's milk, 6 per cent, is in the form of phosphocarnic acid. See Siegfried, Zeit. f. Physiol. Chem. , 1896, xxii. 575 ; and Stoklasa, ibid., 1897, xxiii. 343. Sikes (Journ. of Physiol., 1906, xxxiv. 464) finds that not quite half the total phosphoric acid of human milk is combined with proteid. The ratio of proteid calcium to total calcium is as 84 to 100. HUMAN VERSUS COW'S MILK 453 The chief reason for this is that cow's milk forms a much denser clot in the stomach than human milk. 1 The greater density of the clot is due — (1) to the absolutely larger proportion of casein in cow's milk, and probably also to those chemical differences between cow's and human casein already men- tioned ; (2) to the smaller proportion of fat and soluble albumin relative to the casein which characterizes cow's milk — the soluble albumin and fat of human milk seem to act mechanically in pro- ducing a loose clot ; (3) to the fact that cow's milk contains six times as much calcium and three times as much acid as human milk, and the density of the clot depends very much, as was explained in Chapter VII., on the proportions of these two con- stituents. For all these reasons cow's milk tends to form a dense, retracted clot in the stomach, while the clot of human milk is loose, friable, and easily broken up. In the intestine there is much less difference in behaviour between the two milks. The stools of infants fed on cow's milk are richer in mineral matters than those of breast-fed children, but, then, so is the milk on which the latter are fed. A higher proportion of the fat of cow's milk also escapes digestion than is the case with human milk, and probably also a somewhat greater proportion of proteid ; certainly the faeces of bottle-fed babies contain more nitrogen than those of infants reared at the breast. Infant Feeding with Cow's Milk. Notwithstanding the pronounced differences in chemical composi- tion and physiological behaviour between cow's and human milk, there are some healthy infants who can be reared on the former without modification. 3 This is known as Budin's method. In order to carry it out successfully the milk must be sterilized at 212 F. for forty minutes, and should be given in small feeds, the exact amount being controlled by regular weighing of the infant. As a rule, the infant will require about one-tenth to one-seventh of its weight of milk daily, this being administered in divided quantities at the usual 1 Meyer (Abst. in Maly's Jahrb. Thier-Chemie, 1906, xxxvi. 676), however, believes that he has shown that it is not the casein of cow's milk which is the cause of difficulty to the infant, but some constituent of the whey. 2 See Blauberg, ' Studien iiber Sauglingsfaces,' pp. 107, 108 ; Berlin, 1897. 3 Budin, / nil. de V Acad, de Mid., 1893, 3 me ser., xxx. 157; ibid., 1894, 3""= ser., xxxii. 67. For a summary of the results yielded by Budin's method and a criticism of it, see Marfan, ' Traite de l'Allaitement,' p. 313 ; Paris, 1899. 454 FOOD AND DIETETICS intervals. As the child gets older the amount at each feed is increased, while the duration of sterilization is shortened. The method has the great advantage of simplicity and of practically ensuring satisfactory growth and the absence of rickets. The fear that it may result in scurvy has been exaggerated. In many cases, however, and certainly by all feeble infants, pure cow's milk will be found difficult of digestion, and requires some modification to render it suited to the digestive capacity. From what has been already said, it is evident that such modifi- cation can only affect the quantities of the different ingredients in the milk ; the distinctive peculiarities of the ingredients as opposed to those of human milk will still remain. By suitable treatment, however, the proportion of casein, calcium, and acid salts present can be reduced, and the digestibility of the milk proportionately raised. We must now consider briefly the different methods by which this can be done. i. The simplest method is by mere dilution. The problem here is to reduce the casein and mineral matters in the cow's milk, to leave the proportion of fat much as it was, and at the same time to increase the amount of sugar. Taking the average composition of cow's and human milk, and adding i part of water to i of cow's milk, we get the following comparative results : Human Milk. Cow's Milk. Cow'. s Milk and Water, equal parts. Proteid IS 3 5 1 75 Fat 35 4'° 2"0 Sugar 65 45 2-25 Mineral matter . . - 2 °7 o-35 This makes the proportion of proteid about right, but leaves the fat and the sugar too low. If now one adds to every 4 ounces of the mixture 1 medium-sized teaspoonful of milk-sugar 1 pressed flat and 1 teaspoonful of ordinary centrifugal cream, these defects are rectified, and, except for an excess of mineral matter, the mixture will have approximately the same proportion of each ingredient as human milk. The digestibility of such a mixture is still, however, inferior to that of milk from the breast, for water in this proportion does not prevent the formation of a rather dense clot in the stomach. For this reason it is better to dilute with lime-water or barley-water rather than with plain water. The digestibility of the casein can also be increased by the addition 1 White cane-sugar will also do, but milk-sugar is better. MODIFICATION OF COW'S MILK 455 of citrate of soda in the proportion of 1 grain to every ounce of cow's milk. 1 This acts, as has been already pointed out, by precipitating the excess of calcium salts, and so causing the casein to set into a less dense curd in the stomach. In the case of very young or weakly infants, it may be necessary to dilute the milk more freely than in the proportion given above. In such a case a mixture of equal parts of milk, water, and lime- water is to be recommended, cream and sugar being added in proportionately larger quantity. An ingenious method of overcoming the casein difficulty has been proposed by Von Dungern. 2 It consists in boiling the milk, cooling to 40 C, and adding some pure rennin. Clotting takes place in two or three minutes, and the milk is then thoroughly shaken until all clots have disappeared. It is then ready for use. By this method the casein is not further clotted on reaching the stomach, and is therefore very easily digested. A combination of rennin and milk-sugar for use in the process is sold under the name of Pegnin. 8 2. More elaborate methods are the cream mixtures of Meigs, Rotch, and Biedert. Meigs 4 allows a quart of milk to stand for three hours in a cool place in a tall vessel. At the end of that time he carefully decants the upper half of the milk, which is now rich in cream. To every 1^ ounces of this he adds I ounce of lime-water and ij ounces of sugar-water, which is made by dissolving 8 heaped teaspoonfuls of milk-sugar in 16 ounces of water. This mixture will obviously be poorer in proteid than that described above. The same principle is adopted in the modification of milk by the ' Lupa ' or ' Reed ' Humanizer, both of which are suitable for domestic use. Rotch' s formula 5 is very similar. He takes Cream (20 per cent, fat) . . . . i£ ounces. * Milk . . . . . . 1 ounce. Water . . . . . . • • 5 ounces. Milk-sugar . . . . -.31 drachms. The mixture is boiled, and when cool \ ounce of lime-water is added. It is stated to have the following composition : 1 See a paper by Dr. F. J. Poynton (' The Value of the Addition of Citrate o( Soda to Cow's Milk in Infant Feeding '), Lancet, 1904, ii. 433. a Munch. Med. Woch., 1900, xlvii. 1661. 3 Meister, Lucius, and Briining, 51, St. Mary Axe, E.C. 4 ' Archives of Pediatrics,' 1889, vi. 833, and ' Milk Analysis and Infant Feed. fog'' P- 74 '• Philadelphia, 1885. 6 Described by Cautley, ' Infant Feeding,' p. 150. 456 FOOD AND DIETETICS Proteid .. .. . . 1-2 Fat 42 Sugar 6-5 It is rather too rich in fat for general use. Biedert 1 uses a mixture of 130 c.c. of cream (10 per cent, fat) with 390 of water and 18 grammes of milk-sugar. This results in a milk containing 1 per cent, of casein, i\ per cent, of fat, and 5 per cent, of sugar. For very young infants the mixture may require to be given more diluted. 3. Soxhlet 2 dilutes the milk with half its volume of a 12^ per cent, solution of milk-sugar. This makes the proportion of proteid the same as in human milk, but leaves the fat one-third less and the sugar one-half more. In other words, some of the fat by this method is replaced by sugar. Considering the great importance of fat in the infant economy, it is doubtful if such a substitution is justifiable. Heubner, 3 however, reports that he has fed thousands of the most miserable infants on the mixture with the greatest success. It certainly has the merit of simplicity. 4. So-called humanized milks are now prepared on a large scale by many dairy companies. By diluting the milk .with an equal quantity of water and subjecting it to the action of a centrifuge, it is divided into two equal parts, one of which contains practically all the fat of the original milk but only half of the other ingredients. The deficiency of sugar is remedied by the subsequent addition of that constituent in the necessary proportion. The proportion of proteid in such a milk will tend to be somewhat too low, and the mineral matter still too high, but otherwise the composition will correspond pretty closely to that of human milk. The following analyses of their humanized milks are supplied by the Aylesbury Dairy Company : No. 1. No. 2. "dtiuteQ. Human Milk. Water ., .. 89-43 88 '3 8844 87-6 Proteid .. .. 13 2-2 1-49 1-5 Fat .. .. 40 3-6 359 35 Sugar .. .. 47 5'2 628 6-5 Mineral matter. . 049 C57 020 0-27 Pagefs Perfected Milk Food 4, is a concentrated humanized milk. When diluted with 2 parts of water it yields a fluid of the following composition : 1 See Reinach, Munch. Med. Woch., 1899, xlvi. 956. 2 Munch. Med. Woch., 1893, xl. 61. * Heubner, Berlin. Klin. Woch., 1894, xxx '- 84 1 - * Clay, Paget, and Co., Limited, Ebury Street, S.W. HUMANIZED MILKS 457 Water 8804 Proteid 1 08 Fat 383 Sugar 682 Mineral matter . . . . 023 It is sterile and keeps indefinitely. My own examination of it shows that it is certainly rich in fat, and hardly clots at all with rennet. It is, perhaps, somewhat deficient in proteid. Gaertner's Fettmilck 1 is another commercial humanized milk prepared on the above principles. It is stated to have the following proportions of the chief ingredients : Proteid 15 per cent. Fat .. .. .. .. 32 „ Sugar 60 ,, Mineral matter .. .. 035 ,, With the exception of a somewhat higher proportion of mineral constituents (a point of no importance), these figures are almost identical with those yielded by an average sample of human milk. Very good results from its use have been reported by several observers, 2 although others have put on record cases in which it has disagreed. 3 One defect common to all the above methods must be pointed out. It is true that they bring the total amount of proteid down more or less equal to that found in human milk. They do not, however, influence in any way the relative proportion of the two kinds of proteid — casein and albumin. In all of them the former remains relatively higher than in human milk, and the latter rela- tively lower. For this reason the resulting mixtures must remain more difficult of digestion than human milk. Various methods of getting over this difficulty have been proposed. Hammarsten* takes advantage of the fact that whey contains the albumin of the milk but not its casein (see p. 132), and by making a mixture in the following proportions : Cream 200 parts. Whey 800 ,, or Cream 100 parts, Milk 100 ,, Whey .. .. .. 800 ,, he gets a fluid which contains albumin and casein in the same pro- portion as in human milk. 1 Sold by the Friern Manor Dairy Company. 2 See Gaertner, Wiener Med. Woch., 1896, xlvi. 1004; Fischer and Poole, New York Medical Record, 1897, Hi. 839 ; and Schutz, Wiener Klin. Woch., 1896, ix. 1116 (experiments on adults). 8 Hauser's resume, Fortsch. d. Med., 1897, xv. 929. See also Monti, Wiener Klinik, 1897, xxiii.. Hft. 1,2, and 3 ; and the Year-Book of treatment, 1897, p. 159. 4 Jahres-Ber. f. thierchemie, p. 206, 1895. 458 FOOD AND DIETETICS Ashby 1 was also a strong believer in the virtues of whey. He prepared it by placing 30 ounces of fresh milk in a Hawksley's sterilizer and heating to 104 F. ; two teaspoonfuls of Benger's essence of rennet are added, and the bottle set aside for a few minutes. When curdling has taken place the curd is thoroughly broken up by stirring and shaking, and the whey is then strained off through fine muslin. In this way 22 or 23 ounces of opalescent whey are obtained. This is heated to 180 for twenty minutes to destroy the rennin, and is then. strained again. The composition of the whey so obtained is as follows : Proteid . . . . . . 097 Fat 20 Salts 061 The whey may be used alone with the sole addition of 2 or 3 drachms of milk-sugar to the pint as a food for newly-born infants. A weak 'humanized' milk may be prepared by mixing 10 ounces of fresh milk with 20 of whey and adding \ ounce of milk-sugar. It has the following composition : Proteid 175 Fat 25 Sugar . . 60 Salts o-6 If a milk richer in fat is desired, 'top' milk should be used in the same proportion. To prepare it, let a quart of fresh milk stand in a covered jar in a cold place for four or five hours, remove the upper 10 ounces by skimming, and add to this 20 ounces of sterilized whey and \ ounce of milk-sugar. The mixture should contain 4 per cent, of fat. A grain or two of bicarbonate of soda may be added to the mixtures to render them alkaline. Monti 2 also recommends the use of whey. For the first three months he employs a mixture of equal parts of milk and whey, after that a mixture of two of milk to one of whey. Vigier 3 divides the milk into two equal parts. He skims one and adds the cream to the other. The former is then clotted with rennet, and the whey added to the other half. The resulting mixture has the following composition : Proteid .. .. .. 2 36 Sugar.. 410 Fat 375 Salts .. .. .. .. 075 1 Edinburgh Medical Journal, 1899, N.S., v. 389. 2 Wiener Klinik, 1897, xxiii., Hft. 1, 2, and 3. 8 Quoted by Monti. PERCENTAGE FEEDING 459 Winter 1 goes on a similar plan when he divides the milk into two parts, skims one, and adds the cream to the other. He then coagulates the skimmed portion with rennet, and adds the whey so obtained to the first part. Such a mixture contains the casein and albumin in proper proportions, but is still apt to be deficient in fat. The advantage of whey as a diluent is that it is antiscorbutic, and contains albumin and a little fat. It must be admitted, however, that the preparation of the above mixtures demands more time and trouble on the part of the mother or nurse than one can usually count on. Lehmann 2 dilutes the milk till the casein is in proper proportion, and then adds sugar and cream. In order to bring up the proportion of albumin, he takes the white of an egg, mixes it with four table- spoonfuls of water, and adds one-third of the mixture to the milk. Backhaus 3 removes part of the casein and peptonizes the rest of it by the addition of a combination of rennin, trypsin, and bi- carbonate of soda. Cream and lactose are then added to the whey. The resulting mixture is known commercially as Nutricia, 4 and has a composition almost identical with that of human milk — viz., proteid 1-38, fat 3 - 2o, sugar 6-50, mineral matter o^. 8 It has given excel- lent results in infant feeding. The albumin of milk can now be obtained in a soluble form — Albulactin 6 — and may be used instead of white of egg to enrich cream mixtures in proteid or added to diluted milk. It will probably prove a useful addition to our resources in artificial feeding. In America the modification of cow's milk to suit the requirements of infancy has been reduced to an exact science. This has' been chiefly brought about by the work of Rotch. Milk containing a known proportion of casein is prepared by adding to it standard solutions of cream and milk-sugar in different proportions. A mixture can be prepared of any desired composition. Laboratories have been established 7 in all the principal towns of the United States in which, on the receipt of a physician's formula, a milk containing the exact proportion of each ingredient which the 1 Quoted by Rothschild, ' L'Allaitement Mixte,' etc., Paris, 1898. 2-Archiv f. d. Ges. Phys., 1894, lvi. 558. 3 Journ. fur Landwithschaft, 1896. 4 A. Stiebler, 7, Eastcheap, E.C. s Lancet l Analysis, 1908, ii. 1153. « Johann A. Wiilfling, Berlin, S.W., 48. 7 Walker-Gordon Laboratories. One of these is now open in London (54, Wey- tnouth, Street, W.). 460 FOOD AND DIETETICS digestive peculiarities of any given infant may necessitate can be dispensed as accurately as a chemist compounds a prescription. 1 Useful and desirable as this is in the case of badly nourished or dyspeptic babies, it is an unnecessary refinement in the artificial feeding of healthy infants. There is still one point in which any of the above modifications of cow's milk is lacking. Human milk as it leaves the breast is practically a sterile fluid ; but this is by no means true of cow's milk as it reaches the consumer. It contains, as we have already seen (Chapter VII.), not only the organisms which cause milk to become sour, but also, and not infrequently, the germs of actual disease. These are specially dangerous to infants, because the low degree of acidity which is characteristic of the contents of the infant stomach enables these germs to pass on almost uninjured into the intestine, where they may readily become the seeds of disease. For this reason, then, the destruction of the germs in cow's milk is of the first importance in preparing it as an infant food. The methods by which this may be done have been already considered (Chapter VII.), but it may be repeated here that in most cases simple boiling is sufficient. ' Pasteurization ' of the mixture at a temperature of 70° C will almost certainly ensure the destruction of the disease germs, 2 but if the milk has to be preserved for any length of time ' sterilization ' should be carried out. We have already seen that the digestibility and absorption of the milk are not interfered with by such a process to any important extent. 3 Reviewing the whole question of the modification of cow's milk, it may be said that the first method described (boiling, with subsequent dilution and addition of cream and sugar) is the best and simplest method for domestic use. If, however, expense is no objection, the use of such a commercial preparation as Fettmilch is equally good and less troublesome. The correction of the relative proportions of casein and albumin, although theoretically sound, is practically not a necessity in the case of healthy infants. When all is said and done, however, cow's milk, no matter how skilfully modified, is much inferior to human milk as a means of feeding infants, this probably depending on those qualitative differences in the composition of the two fluids which no method of modification can entirely overcome. 1 Wentworth, however, has shown that the mixture as dispensed does not always exactly conform with the formula ordered (' The Importance of Milk Analysis in Infant Feeding,' Boston Med. and Surg. Journ., 1902, cxlvi. 683 ; ibid., Ig02, cxlvii. 5). 2 It has not been conclusively proved capable of destroying the tubercle bacillus. 3 The only disadvantage attending the use of boiled or sterilized milk seems to be that it is occasionally the cause of infantile scurvy. [ 4 6i] CHAPTER XXVI THE PRINCIPLES OF FEEDING IN INFANCY AND CHILD- HOOD (continued) : OTHER SUBSTITUTES FOR HUMAN MILK (PEPTONIZED MILK, CONDENSED MILK, PROPRIETARY FOODS) ; FEEDING OF OLDER CHILDREN i. Partially Peptonized Milk. It is believed by some authorities that one of the essential differences between the casein of human milk and that of the milk of the cow is that the former is really a stage nearer the digested condition (i.e., peptone) than the latter, and that the more easy digestibility of human casein is due to that fact. Whether this be so or not, there can be no doubt that even the partial peptonization of cow's milk renders it much more easy of digestion. Of complete peptonization there is no need to speak here. It is of the greatest utility as a temporary expedient in some cases of disease, or in feeble and exhausted babies, but is not really required for healthy infants. Sooner or later the stomach must be educated up to dealing with pure cow's milk, and the sooner the education is begun the better. Partial peptonization, however, may often be had recourse to with advantage as the first stage in this process of education in the case of infants whose stomachs have a greater difficulty than usual in dealing with cow's casein. It can be conveniently carried out by means of Fairchild's Peptogenic Milk-powder. Each of these powders contains the ferment required to digest a certain quantity of milk, along with some bicarbonate of soda, which renders the milk slightly alkaline, and enough milk-sugar to raise that ingredient to the pro- portion found in mother's milk. By following the directions supplied with the powders/the process of digestion is only carried so far as partially to change the casein of the milk, sufficient to prevent its clotting, but not enough to 1 In preparing the milk for an infant with a very delicate digestion, it is advisable not to add so much cream as is recommended in the directions. The relative proportions of milk and water and the duration of peptonization can also be varied to suit different cases. 462 FOOD AND DIETETICS absolve the stomach from all further labour. Thus, digestion is rendered easy without the stomach being demoralized. The use of these powders is strongly recommended by Professor Chittenden. 1 He analyzed the resulting mixture, and compares it with human milk as follows : u j^-ni Milk prepared by Human MM. Pe p toge J c &iik-p icUr. Specific gravity .. .. 1031 1032 Water 867 860 Proteid 20 8 209 Fat .. 4-1 438 Sugar 69 7-26 Mineral matter . . . . 02 0-26 Total solids .. .. 132 13-9 Reaction Alkaline. Alkaline. It will be observed that the two fluids are almost identical in composition. I find, too, that milk prepared by this method does not clot with rennet, even in the presence of a considerable amount of acid. 2. Condensed Milk. The importance of studying condensed milk will be realized when it is learnt that 500,000 cwt. of it are imported into this country every year, and there is no commoner substitute for human milk, especially amongst the poorer classes, than this. (a) Chemical Composition. — Condensed milk is simply cow's milk from which a large proportion of the water has been removed. The removal is effected by evaporation under reduced pressure and with the aid of a greater or less degree of heat. As a rule, the milk is only reduced to one-third of its original volume, so that in order to restore it again to the condition of the original milk all that is necessary is to add to it twice its volume of water. Unfortunately, however, the milk used for condensation is not always pure milk. Very often the cream has been removed from it by a separator, so that the product is really condensed skim milk. Cane-sugar is also frequently added to the milk after condensation, in order to aid in its preservation. As a matter of fact, all the condensed skim milks found in the market have also been sweetened, so that one may divide condensed milks into the following groups : 1. Unsweetened and condensed whole milk. 2. Sweetened and condensed whole milk. 3. Sweetened and condensed skim milk. 1 New York Medical Journal, 1896, lxiv. 71. a The proportion of proteid here given is probably too high. CONDENSED MILKS 463 I. Of the unsweetened condensed whole milks there are four examples, which have. the following composition 1 : Brand. Total Solids. Proteid. Fat. Milk-sugar Ideal 38-0 8-3 124 i6'o First Swiss 367 97 105 142 Viking 34'2 90 100 133 Hollandia . . 430 113 98 185 If 1 part of such a milk is diluted with 2 parts of -water, the resulting fluid corresponds more or less closely to a good sample of pure cow's milk. One disadvantage of the unsweetened milks is that they are apt to go bad when the tin has been opened. For this reason they should be kept in a cold place. It would be an advantage also if the manu- facturers would put up such milk in small tins, one of which would be sufficient for a day's supply. 2. The sweetened condensed whole milks contain, as a rule, rather more added cane-sugar than there are solids in the milk. The following is the composition of some of the best brands ; they are arranged, again, according to their richness in fat : Brand. Total Solids. Proteid. Fat. Milk-sugar. Cane-sugar. Nestle . . • 77'2 97 137 150 37'2 Rose . 766 8-3 124 176 361 Milkmaid • 763 97 iro 146 387 Full Weight • 765 123 no 135 37' 2 Anglo-Swiss • 74'4 8-8 108 160 37i There are many other brands in the market besides these, but none of them is superior to the above. Now, although the members of this group contain as much fat as the unsweetened condensed milks, yet so much sugar has been added that if they are mixed with only as much water as has been removed in condensation, the resulting fluid would be so sweet that one could hardly drink it. Hence, a degree of dilution is recom- mended on the tins of these brands which renders it impossible for the resulting fluid to be at all like cow's milk in its proportion of proteid and fat. 3. Of the condensed separated (or skim) milks there are an immense number in the shops. They resemble in composition the second group just described, except in that they contain almost no fat (always less than 2 per cent.). When diluted in the proportions recommended for infants, the resulting fluid is very poor in proteid and almost free from fat, and is therefore entirely unsuited for a baby's nourishment. 1 The analyses of condensed milks in this chapter are taken from Pearmain and Moor's 'Analysis of Food and Drugs,' part i., pp. 69-78. 464 FOOD AND DIETETICS (b) Digestibility of Condensed Milk. — It must be admitted that condensed milk is more easily digested than fresh cow's milk. When diluted in such proportion as to restore them to the con- dition of ordinary cow's milk, the condensed milks either do not clot with rennet at all or the resulting curd is much looser than in the case of pure cow's milk. 1 The presence of acid does not affect the result. The explanation of these facts probably is that the casein undergoes some chemical change in the process of condensa- tion which renders it unfitted to form a dense clot. Certainly this greater digestibility is one point in favour of condensed milk, and justifies its occasional use for infants who are entirely unable to digest ordinary cow's milk, even when specially modified. 2 (c) Nutritive Value and Economy of Condensed Milk. — The chief defect of condensed milks from a nutritive point of view is that they are apt to contain too little fat. The unsweetened milks are alone satis- factory in this respect. The skim milks are absolutely to be con- demned on that account, and even the sweetened whole milks, though they contain all the fat of the original milk, yet require so great a degree of dilution, owing to the amount of sugar which they contain, that the product is notably deficient in fat. ' The following table shows the character of the liquid — it cannot be called milk — that is produced by following out the directions on the labels of half a dozen of the best brands of (sweetened) whole-cream milk ' (Pearmain and Moor) : c , 3 Dilution recommended ,-. . ■ , Dilution ^ . . , Sweetened , „ , , , Fat in such . . , Fat in such Whole Milk. *»gg? Product. «%£$*£ Product. A .. 1 to 3 26 per cent. 1 to 5 18 percent. B .. 1 ,, 5 r6 ,, 1 ,, 14 07 ,, C .. 1 „ 5 i-6 „ 1 ,,' 14 o-6 „ D .. 1 .. 6 14 „ 1 ,, 15 07 „ E .. 1 ,, 5 21 „ 1 ,, 14 o-8 „ F •• 1 .. 5 17 » * .. J 4 07 „ G .. 1 „ 5 17 „ 1 ,, 14 07 „ Human milk .. — — . — 3 5 .1 There can be no doubt that an immense amount of harm is done to infants by the indiscriminate use of such milks. Babies fed on them may look fat enough, but they are pale and flabby, and often suffer from rickets, for fatness produced by abundance of sugar in the milk is, as has been already pointed out, by no means a sure indication of health, and the pictures of such fat but flabby infants so freely spread abroad by the makers of condensed milks are very deceptive. 1 The experiments were performed with the First Swiss brand and with Nestle's. 2 The great degree of dilution in which condensed milk is usually given no doubt also explains in part the ease with which babies digest it. CONDENSED MILKS 4^5 If a sweetened condensed milk is used at all, it should only be for a short period, and the deficiency of fat should be made good by the addition to the diet of cream or cod-liver oil. Babies of delicate digestion often do well for a time on Nestle's milk in the proportion of one teaspoonful to six tablespoonfuls of water. Such a mixture contains 1-13 per cent, of proteid, 1-28 per cent, of fat, and 6*72 per cent, of sugar, and by the addition of one teaspoonful of centrifugal cream to each feed the fat is brought up to 3 per cent. The casein in this mixture, being very dilute, is easily digested, and the relative excess of sugar does no harm if such a method of feeding is not continued beyond the fourth month. The only kind of condensed milk which can be unreservedly recommended, however, is that made from whole cow's milk with- out the addition of sugar. If 1 part of such a preparation is diluted with 2 parts of water, the product may be regarded as identical with good cow's milk, and will therefore require further dilution, sweetening, and addition of cream, just as fresh milk does (P 454)- Used in this way condensed milk is convenient in cases in which fresh milk is for any reason unobtainable, or for temporary use in the case of infants who are unable to digest the latter. There is, however, one disadvantage in its use which has yet to be men- tioned. It has been found that infants fed exclusively on tinned foods are apt to suffer from a peculiar disease of the blood and bones which resembles scurvy. Infants fed on fresh milk never suffer in this way, for fresh milk contains some 'antiscorbutic' element which has not yet been identified. 1 In order to counteract the tendency to this disease, it is well to give infants which are reared on condensed milk a little orange or grape juice two or three' times every week. The question whether condensed milks are to be regarded as sterile or not is one of some importance. It seems to be by no means certain that they are, for the degree of heat to which they are subjected during condensation is not necessarily sufficient to kill all disease germs. It would be well, therefore, to boil the condensed milk after dilution and before giving it to the child. As regards the question of economy, there is nothing to be said in favour of condensed milks. The cost of manufacture is bound to add considerably to that of the original milk, and, as a matter of 1 It is worth considering whether the citric acid in fresh milk may not be such an element. It is apt to separate out in an insoluble form in condensed milk, 30 4^6 FOOD AND DIETETICS fact, their cost is equivalent to that of cow's milk at nearly 4d. per pint. 1 In other words, the removal of two-thirds of the water from the milk has about doubled its cost. 3. Proprietary Foods for Infants. There is an immense number of patent infant foods, almost every one of which claims to be ' the best food for infants ' or ' a perfect substitute for mother's milk.' These claims are devoid, of course, of all scientific justification, for, as regards the former, no one will deny that the best food for infants is human milk, and as regards the latter, it has already been shown that cow's milk can never be so modified as to resemble human milk in its qualitative composition. Further, the ingredients of any patent food for infants require to be carefully scrutinized, for many of them contain unaltered starch, and starch is not a substance which can be given with impunity to all infants, even although some of them are able to digest a little of it without harm. Many of them, too, are lamentably poor in fat, the importance of which as a constituent of an infant's diet has already been fully insisted upon. A deficiency in proteid is another common fault amongst them, and this, especially if combined with poverty in fat, may explain the frequency with which rickets is observed in babies reared upon such foods. As there is a con- siderable degree of discrepancy in the published analyses of these preparations, I have submitted the majority of those found on the English market to a fresh examination, and the results, along with a brief description of each particular food, are contained in the following table : 1 A tin of condensed milk contains about 290 c.c. This, diluted with 2 parts of water = 870 c.c, or about i£ pints of cow's milk, and the original tin costs 5^d. INFANT FOODS 467 P O O fa H 55 < fa fa O 55 O O fa o u W H O 55 3 J3 .O CO (O cd C rf XI a 3 B ft o a o £ a -2 CO c a) O H d2 .9 3 • *o 2 <* s lis .s"S Iffi ca .. rt a o t. ■2 co g 3 CD CO ^ O bo g,£ 3 ti £? to c -t- i-« s .sp & a ■d c ;S.£\2 « J>" "3-a is So a §. - ca jc v, O 3 s h ° J °f 111 4) °J a ^2 18.3 ■SSo «, c 9 « ° ■?n P CD 1) XI' ♦J "i±i c ■ H "e3 ^ 1 -a 3 c t 5) en — I > - ri ^ c <« B E o"5 CD B v CO cd >2-S "§■^■5^0 S S 5 S en d c -2ca »E«? < PU 'C CD CJ * O T3 ci in 4] 01 S I30S o.tS.2 d, ^.S-2 « «i.2i''" CD-O O g O ° <*> ™ . t. 3 U CO rf 3 c 2 ^^ co 3 rt < o SS 5 ir> O O X in W P m " I C CD E 3 XI ■a xi « u a K ^ o O 3X> „ XI CD 3 !-. CD J) XI 3 -a E : SitD OT3 . Cu —4 < Si in Xl 3 "o V) SB 3 ■a o o fa o fa 3 XI o S % 30— a 468 FOOD AND DIETETICS P O O H < I— H O O ja o O CD •3 ° o , 0-2 "3 "! P S S V Una's .33 f3 E U CU CD 6— ° ■8.3 S .2 - — 3 rt o 3J3 -M o "3 .g "Up. C« H4 .S *j ,,T3 & d d d J- . ■Si! E 3 *§ S ° | a »■ • 0, a.g S " fi-a « 3 U S o V 5 s a u ■B<8 '$ u 0) en 3 a , . Kb -a ■" S a - eg £ to *a 8 - * 8 £ O.J3 *• .5 -S a^ *S* " d O j* . ■d .1 T3 "3 T3 ** 5 J) C Bl ^ r« P Jn'i - — •S-S^SBi^siSg d . ^T o . _ SI n.r'TI _. T3 a d B" - w °. u a — S § ° ° O -£ * :3 co d ° — d •""« _5 a o^« S d£ = »r„°3 =3 -° cc „ o -g " «-3 °,— d s d — J? «J -. o 'B 2 'e ■" -3"b a & a E u "S d « ■E w ° S oH o So g O •— iO » ^^r! S °S 0.0 a>3 a v_S -13 ^■S §S a o P g 3di2 ■ °sa en O SS O u w H a 55 o EC C7) Pd W ° o 8 A In fel3' JW o fe 85^ *^! " m §S S3 G 'l +3 co u •a« o > d 73 O O p-| o J! h 3 -a 3 CD "3 5 ■§£b 2 co 3 .Sea CD d CD INFANT FOODS 469 E d.S O.P ft to o § S § S 8 -• S.S *!»§.«' «•-— s c c fl) "^ G 0) 3 & d ° >-S o "O" c . « s c o " .5 ja 5 o ■ •2-3 °--- 1 °'3 .— o +"* *D — • ' a tt *+« ^ <■> ■ r3 'h » u »« n ■O O 3.2-a o a) ■£ o m a *3 "dug S13 « C 1- C ^ ~ U c bOK b; 3 o ^■81 ■a u -"^3 8 S "-a »■" . ]) m o c' 1 2 -a d 6 8 O J3 a," 5 bo O m _ft>3. ^ o bo "to ft "2 -B 50 »-° .5.3 d d og > ,-•0 5 a> 3-5«* * § h.2 u m a ■* E j. JD 3 O (U in to # cd *— M-( +j 3 £ S §J3 p. a". H •BBS'S •-! h O [fi ^ H tfl O B u. rt >. fl a- « < 3 3 ° m m W n *j tn m rt g —1 s^WJ (fl ? - 1 " O O t; >** •8. Si ft S ** 3 « „ J3 O-S " is-- 3 ra >h B(/) 3 -w c ° . a 2 53 -S H a) tpj 2 _3 (U s ■3 ^2 is (0 1 ■*-• CO ■a c ^ ■ — — 2-?J«3 ^8 6 3- 3 en ' -a "2 ■o.S S S u £ 1° § S CO ■■ s 'tf a b ro N N 00 O <^ « 10 J> U1 (^ ^ s £ J3 E o o o •a o o fn "id bo •a 2 T3 O O b B 2 (H ■a o o °a m c« H o a •— 3 " (O rt ;5 -2 .3 « J3 O o PQ o & in "S B 3- J5 o 0! o w "ft\ O a O d 1) o. ■o *: ■" o en cu CJ u ■* u 2 S . .Eo. W« >. •£ . o it o a> 55 2\& S.s-5- •o c - « j o ft! < « ^- vi — .. S= "^ r >( E M d S-2"§ .2<^ S»» d 2 S u G 5S i) <>-i'2 tu 470 FOOD AMD DIETETICS In judging of the value of these numerous preparations, One may divide them into the following groups : i. Foods prepared from cow's milk with various additions or alterations, and requiring the addition of water only to be ready for use. This group includes : < Allenbury ' first and second foods. Carnrick's Soluble Food. Horlick's Malted Milk. Milo Food. Manhu Infant Food. Muffler's Food. Glaxo. Lak Cit. Comparing these preparations with the composition of dried human milk (see table), one observes that they are all (with the exception of Glaxo) deficient in fat and too rich in carbohydrate. In some of them, also, there is insoluble carbohydrate (starch) present, which is not suitable for infants (see p. 435). The com- position of some of them when ready for use is contained in the following table, and fully bears out these criticisms : Human Milk. 1 A llenbury Food,, No. i.» Milo Food. 3 Malted Milk* Glaxo} Water 87-60 88-30 9276 92-40 91-10 Proteid .. 1-52 156 o-8i i-i5 218 Fat 328 230 036 o-6o 2-52 Sugar 650 7-20 3-8o 5-38 368 Mineral matter . . 0-27 060 013 0-29 0-52 The essential constituent of all these foods is dried milk, to which milk-sugar, malted flour, etc., have been added. Glaxo, however, contains nothing but the ingredients of milk, and is the only member of the group which contains as much fat as human milk. The casein in all of them, however, is easily digested, as it clots loosely, if at all, with rennet. They are therefore often well borne by delicate infants, but their poverty in fat renders them unsuitable for prolonged use. They are also not free from the risk of producing scurvy, although this danger need not be feared if their administration be confined to the first three months of life. 2. The second group consists of farinaceous foods prepared from cereals {usually wheat), of which the starch has been partly or wholly trans- formed into soluble substances (dextrins or malt-sugar), and which require 1 Camerer and Soldner's analysis. 2 Analysis by the author. 3 Analyses by Chittenden {New York Medical Journal, 1896, Ixiv. 17). 4 Ibid. 6 Analysis by Droop Richmond, MALTED FOODS 471 the addition of milk to fit them for use. The group may be sub- divided into two classes : (a) Those in which the starch has been transformed before reaching the consumer — e.g., Mellin's Food, Cheltine Maltose Food, and Hovis Babies' Food No. 1. (i) Those which contain malt or pancreatic ferment, which convert the starch when the food is mixed-^e.g., Benger's Food, Savory and Moore's Food, Moseley's Food and others. When one compares the composition of these foods with that of dried human milk, one is struck again by their great deficiency in fat. They are also defective in mineral matter and proteid. If mixed with water alone, therefore, these foods could never be true substitutes for human milk. In all of them, however, the addition of some fresh cow's milk is recommended, although the proportion is often very small. They can only be of use in supplementing the diet of infants who are unable to digest much cow's milk, but the only elements they supply are carbohydrate and, to a less extent, proteid. Their addition to cow's milk seems also to aid the digestion of the latter, probably by acting mechanically on the curd, as barley- water does. They may also be regarded as useful (though costly) additions to the diet of the infant after its sixth month. As regards the relative merits of the two classes into which the group is divided, it may be said that there is no advantage in a food in which the conversion of the starch only takes place during the preparation of the food for use. On the other hand, the disadvantages of such a plan are obvious, for the result is at the mercy of the skill and care of the mixer, and, as a matter of fact, the conversion of the starch in many of the second class is by no means complete, even when the directions are carefully followed (see last column of table). It is undoubtedly better to use a food such as Mellin's, in which the conversion of the starch has been completely carried out in the process of manufacture. The composition of Mellin's Food, when mixed and ready for use, is as follows : Water Proteid Fat .. Carbohydrate Mineral matter Human Milk. 1 Mellin's Food* 8760 8800 1 52 2 62 328 289 650 5-98 027 047 1 Analysis by Camerer and Sbldner. 8 Analysis by Chittenden (New York Medical Journal, 1896, Ixiv. 71). 472 FOOD AND DIETETICS 3. The third group includes farinaceous foods in which the starch has not been predigested. It includes such foods as Ridge's, Neave's, Frame Food Diet, Chapman's Whole Wheat Flour, Robinson's Patent Barley and Groats, and others. These pre- parations are open to the same objections as those in the second group, with the additional disadvantage that they contain much starch which has either not been acted on at all or only rendered slightly more digestible by the process of baking to which most of them are subjected in the course of manufacture. Now, into the question to what extent infants are able to digest unaltered starch we need not enter here. One may admit that recent observations have shown 1 that even quite young infants are able to digest much more starch than was formerly believed. The practical fact, how- ever, remains, that starch forms no part of the diet of a naturally- fed infant until, at least, after the cutting of some of its teeth ; and, further, experience shows that the presence of unaltered starch in the diet of young infants is prone to excite disorders of the stomach and bowels. A consideration of these facts renders it evident that foods belong- ing to this group should be avoided altogether before the infant has cut any teeth. Their addition to the diet after that period will undoubtedly furnish the child with an increased amount of proteid and carbohydrate, but such articles as rusks, bread-pap, oat flour, and rice 2 will do so quite as efficiently, are as easy of digestion, and have the practical advantage of being very much cheaper. It may be convenient to sum up at this point what we have learnt as to the practical rules for guidance in the feeding of infants. 1. Breast milk is always to be preferred ; ' humanized milks,' though right in theory, are not found to be perfect substitutes in practice. 2. If the child does not gain, or loses weight, on the breast, try mixed feeding, using the breast along with modified cow's milk. 3. If the breast is inadmissible, a healthy infant may be reared on pure sterilized cow's milk ; a feeble infant will require modified cow's milk. 4. The simplest method of modification is by dilution plus the 1 See Berlin. Klin. Woch., 1895, xxxii. 201, and a paper by Carstens at the 67ten Versammlung Naturforscher und Arzte zu Liibeck, 1895, Med. Abth., p. 161, also Parker in Medical Society's Transactions, 1887, x. 319. The whole subject has been discussed more recently by Corlette (' A Review of the Subject of Starch Digestion in Young Infants,' Australasian Medical Gazette, 1905, xxiv. 1) ; and by Cautley (' Starch Digestion in Babies '), Lancet, 1909, ii. 1343. 2 The starch of oats and rice is more easily digested by infants than any other. INFANT FEEDING 473 addition of cream and sugar ; but where expense is no objection, one of the humanized milks or ' fettmilch ' may be employed. 5. If the infant is unable to digest cow's casein, even when the milk is much diluted, partial peptonization may be employed. 6. Condensed milks should only be used temporarily — e.g., during digestive disturbance or where fresh milk is unobtainable. The addition of fat will always be necessary. 7. Few proprietary foods in the market possess any real advantage over the best brands of condensed milk, and they should all be avoided as complete foods for infants if fresh milk is obtainable. If used before the child has cut its teeth as additions to a diet of milk, those only should be employed in which the starch is entirely converted into soluble forms. The patent foods in which the starch is unconverted possess no advantages as additions to the diet of older children over such simple articles as oat-flour, rusks, and rice, and are considerably more expensive. In those rare cases in which an infant seems incapable of digesting the casein of cow's milk even when peptonized, it may be necessary to have recourse to various artificial mixtures, such as whey and cream, white of egg and whey, bread jelly, 1 or raw meat juice. Midelton 2 strongly recommends the use of eggs in such cases. He advises the following method of procedure for an infant weighing 6 pounds or more at birth : During the first two days after birth beat up the raw white of a large new-laid heri's egg, add to this water to make 8 ounces, also 40 grains of pure cane-sugar. Strain through butter muslin. Put 1 ounce of this into the feeding bottle, stand it in hot water at 1 io° until the food is raised to 98° F. Feed every hour and a half. On the third or fourth day add 5 minims of the yolk of the egg and 5 minims of raw meat juice to each feed. Increase the quantities gradually as the child grows older, and also add cod-liver oil emulsion to each feed, say 5 minims of a 40 per cent, preparation. 1 Bread jelly is prepared as follows : A thick slice of bread (4 ounces) is baked in a basin of cold water for six or eight hours and then squeezed out. The pulp is gently boiled in a pint of fresh water for an hour and a half. The gruel thus made is strained, rubbed through a fine hair sieve, and allowed to cool, when it forms a smooth jelly. Enough of this is mixed with warm water to make a food of the consistence of thin cream ; a little white sugar may be added (Cheadle). 2 Brit. Med. Journ. , 1907, i. 1302. 474 FOOD AND DIETETICS The Feeding of Older Children. 1 - After weaning — which should take place not later than the tenth month — the diet becomes of a more solid character. The same principles must be observed in its composition, however, as in the case of infants ; that is to say, the building material and fat must be relatively more largely represented than in the diet of adults. The importance of a sufficiency of proteid in the diet of children can hardly be exaggerated. Much of the feebleness, flabbiness, and pallor of the children of the poorer classes in large towns is no doubt due to a lack of it. There is reason also to believe that a similar deficiency may be a cause of the stunted and ill-developed bodies which such children often show. The dearness of meat is largely responsible for these conditions. 2 The following computations have been made of the amount of each nutritive ingredient required at different ages 3 : Age. Proteid. Fat. Carbohydrate. ij years . . . . 42-5 grammes. 35 grammes. 100 grammes 2 „ .. •• 455 !■ 36 „ no ,, 3 .. •• .. 50 »» 38 „ 120 i> 4 .. •• •• 53 »5 4i'5 », 135 35 5 ,. ■• .. 56 t 43 145 35 8 to g years .. 60 51 44 150 35 12 to 13 ,, .. 72 „ 47 245 55 14 t° 1 5 .. •• 79 .. 48 ., 270 91 Atwater's calculation is as follows : A child under 2 years requires 03 the food of a man at moderate work. A child of 3 to 5 years requires 04 A child of 6 to 9 years requires 05 A child of 10 to 13 years requires 06 A girl of 14 to 16 years requires 07 A boy of 14 to 16 years requires 08 The ratio of building material (proteid) to carbohydrate and fat is as 1 : 4"2 - 4-8 in the average child's diet. In that of the adult at moderate work it is as 1 : 5*3 - 5*5. It will be noted also that fat is relatively more abundant in the diet of the child. There is 1 part of fat to 3-7 of carbohydrate in the child's diet, while the proportion in the adult is 1 to 4 (Atwater), 1 to 4*8 (Moleschott), and 1 to 8*8 (Voit). 1 For a discussion of this subject see Dr. Joseph E. Winter's ' The Food Factor as a Cause of Health and Disease during Childhood ' (New York : William Wood and Co., 1902). 2 See also Clement Duke's ' School Diet,' second edition, chapter iii. 3 Schroder, ' Ueber die Ernahrung 8-15 jahriger Kinder,' Archiv. f. Hygiene, 1886, iv. 39. See also diagram, p. 47, and a paper by Heubner (' Eine Betrach- tung ueber die Ernahrung des kindes jenerseits der Sauglingsalters,' in Jacobi's 'Festschrift,' p. 290). DIET AFTER WEANING 475 Roughly speaking, a child of five requires half as much fat and building material as a full-grown man doing a moderate amount of work, but only one-third as much carbohydrate ; while a boy of fifteen will require as much of every ingredient as a full-grown man leading a sedentary life. One must now say a few words as to the sources from which the difFerent ingredients of the diet should be derived. Even for some time after weaning, cow's milk should still be the chief source of proteid. It may be supplemented at the end of the first year by small quantities of yolk of egg, and chicken, fish, and a little underdone meat may gradually be added. These animal substances are the best sources of proteid, because they contain it in a concentrated and easily-digested form. It is possible, however, to rear healthy children on a diet the proteid part of which is almost entirely derived from vegetable sources, 1 especially if the child is able to lead an active and out-of-door life. Thus, a German author has recorded the case of an institution in which only one- eighth of the proteid in the children's diet was derived from animal sources, and yet the inmates . were all well nourished and fully developed. He attributes this good result to the fact that the children were working out of doors most of the day, and were accustomed to the diet from their infancy. In most cases, however, it is safer to supply at least one-third of the total proteid required in an animal form. 2 The best vegetable proteid-yielders for children are oats (oat flour, groats, and rolled oats), wheat (whole wheat flour, macaroni, semo- lina, or such patent wheat foods as Opmus and Florador), such preparations of maize as hominy and cerealine, and, amongst the pulses, lentil flour. Fat should be derived from such sources as good milk, butter, the yolk of egg, and bacon. Difficulty is often found in getting the child to take enough fat, but its importance in the diet is such that pains should be taken to educate the child in this respect. By giving it in a state of fine division the difficulty may often be over- 1 See cases described by Schroder, he. cit., p. 453. » ' During the period of growth,' says Clement Dukes (' School Diet, p. 32), ' there should be a tolerably even balance between the amounts of farinaceous and vegetable food, with a large preponderance of animal food, the total supply required being largely in excess of that demanded by adults, in order to supply the material necessary for growth and development as well as wear and tear." He is assuming, of course, that regular daily exercise is enforced. He is of opinion that growing boys should have meat twice a day — once to make good wear and tear, and once to provide for growth. The total daily allowance should be 9$ ounces of cooked meat. 476 FOOD AND DIETETICS come. Thus, butter spread on bread or mixed with mashed potato may be taken when more solid fat would disagree or be refused. Suet pudding also contains fat in an easily-digested form. If any carbohydrate be added to the diet at all before the teeth are cut, it should, as we have seen, be in a soluble form. In other words, it should consist of some form of sugar or dextrin, starch being excluded. Even up to the end of the first year it is well to avoid purely starchy foods, unless in very limited amount. It is at this period that one of the patent foods, in which the starch is partially digested, may be of service. After the first year more solid starchy food may be given. Rice, potato and oat flour are the most easily digested forms. Biscuits or rusks, too, are more easily digested than ordinary bread, because the high degree of heat to which they have been exposed ruptures many of the starch grains, and converts part at least of their contents into soluble forms. The following is an analysis of two such preparations : Rusks (Montgomerie's). Dr. Jago's Analysis. Water . . . . . . 69 Proteid .. .. .. 115 Starch . . . . . . 604 Maltose . . . . . . 142 Other soluble matters . . 60 Phosphoric acid . . 03 Rest of ash . . . . 04 Dorina Nursery Biscuits. Dr. Gregory's Analysis. Water .. .. .. 794 Proteid . Starch . Maltese Dextrin Fat Ash 941 4733 1662 1058 988 1 24 Robb's Nursery Biscuits are also a serviceable preparation of a similar sort. Bipsine Rusks are made from malted wheat with the addition of casein. They contain 15 per cent, of proteid, and are said to be rendered more digestible by having been treated with pepsin. Nurso Rusks 1 are very similar. Both of these are of much higher nutritive value than ordinary rusks. Arrowroot, cornflour, Oswego, sago and tapioca are useful forms of starch, which may be given in the form of puddings, but they possess no advantage over rice, and it must be remembered that they are practically devoid of proteid. Sugar is one of the most important forms in which carbohydrate can be added to the diet of children. The great reduction in the price of sugar which has taken place in recent years is probably one of the causes of the improved physique of the rising generation. The fear that sugar may injure children's teeth is largely illusory. 1 Callard and Co. DIET OF CHILDREN 477 The negroes, who live largely on sugar-cane, have the finest teeth the world can show. If injudiciously taken, sugar may, however, injure the child's appetite and digestion. The craving for sweets which children show is no doubt the natural expression of a physio- logical need, but they should be taken with, and not between, meals. Chocolate is one of the most wholesome and nutritious forms of such sweets (p. 275). Jam is also an important vehicle for adding carbo- hydrate to the dietary. The claims of jam versus butter have already been considered (p. 136); but I would only point out here that so great is the importance of fat in the diet of childhood, and so few the forms in which it can be given when compared with the abundant choice of different varieties of carbohydrate, that one must on no account allow jam to replace butter, or even dripping, as the habitual accompaniment of the child's bread. The mineral matters, which are so important for building up the bones, muscles and blood of the growing child, should be chiefly derived, during the first two years at least, from milk. Abundance of milk in the diet will ensure a sufficient supply of the three most important ingredients — lime, potash and phosphoric acid. 1 Eggs, too, are rich in these elements, and the yolk of egg especially shares with milk the advantage of containing much phosphorus in an organic form. Iron is contained in yolk of egg, the red meats, and in such vegetable substances as oatmeal. The vegetable salts of potash, which occur so abundantly in fruits and green vegetables, are also of importance, and such articles should always find a place in the child's menu. Of beverages it need merely be said that water is the only one suited for young children, but care should be taken that it is pure. Alcohol in all forms should be avoided as being entirely unnecessary for healthy children. Tea and coffee are also harmful to the susceptible nervous system of the child, but cocoa, made with plenty of milk, may be allowed, though it should be regarded, like milk, as a food rather than a beverage properly so called. Schemes of diet for children of school age will be found in the work of Dr. Clement Dukes already referred to. 2 The following schemes of diet for young children illustrate the practical application of the above principles : 'Dr. Ferguson, the factory inspector, concluded from careful continuous measurements of factory children that between thirteen and sixteen years of age they grow nearly four times as fast on milk for breakfast and supper as on tea and coffee. 3 ' School Diet,' p. 174 et seq. (London : Rivingtons, 1899). 478 FOOD AND DIETETICS I. Diet from 9 to 12 Months. First Meal, 7.30 a.m. Milk thickened with groats, oat-flour, Chapman's Whole Wheat Flour, Mellin's Food, Savory and Moore's Food, or Allenbury No. 3. Second Meal, 10.30 to 11 a.m. Warm milk, pure or diluted with one-third of lime-water. Third Meal, 1.30 to 2 p.m. Warm milk, with the addition of the yolk of a lightly boiled or raw egg. A little veal broth or good beef-tea occasionally as a change. Fourth Meal, 5 p.m. Same as first. Fifth Meal, 9 to 10 p.m. Warm milk. During this period the use of a bottle should be gradually discontinued, and the child fed with a spoon or accustomed tp drink out of a feeding cup or ordinary cup. The amount of milk taken in the course of the day should not exceed two pints. If the child be thirsty, he may be given a little water between meals. From about the tenth month onwards, something to chew should be given occasionally, such as a rusk or crust, or a piece of sponge cake or stale bread- and-butter. II. Diet from 12 to 18 Months. First Meal, 7.30 a.m. A breakfast -cupful of milk thickened with groats, fine oatmeal, whole wheat flour, or hominy. Bread or rusks and milk as a change. Second Meal, about 11 a.m. A cupful of warm milk, pure or with the addition of one-third lime-water. Third Meal, 1 to 1.30 p.m. Beef-tea, mutton or chicken broth, thickened with bread crumbs or sieved potato ; as a change, the yolk of a lightly boiled egg. Some milky rice or bread pudding, with the addition of some of the pulp of a roasted apple or the pulp of stewed prunes. Fourth Meal, 5 p.m. Milk and bread-and-butter. Fifth Meal, 9 p.m. Warm milk. III. Diet from 18 Months to 3 Years. First Meal, 8 a.m. Porridge and milk, followed by the yolk of a lightly boiled egg or bread dipped in bacon fat. Stale bread, crisp toast or a rusk. Milk to drink. Second Meal, 12.30 to 1 p.m. A little pounded or minced chicken or underdone meat or fish. Milk pudding and stewed fruit. Water to drink. Third Meal, 4.30 p.m. Bread-and-butter ; sponge or other plain cake occasionally. Milk. Fourth Meal, 6.30 p.m. Warm milk and a biscuit. [479 j CHAPTER XXVII THE PRINCIPLES OF FEEDING IN DISEASE In this and the succeeding chapter we pass on to consider the use of food as a therapeutic agent in the treatment of the sick. In dealing with this part of the subject, it will be well to confine our attention as far as possible to the discussion of principles, and to avoid those detailed instructions for the dietetic management of particular cases which find their appropriate place in text-books of therapeutics. If the general principles involved are once fairly grasped, the know- ledge we have already acquired as to the composition and uses of different foods should be sufficient to guide us in drawing up a dietary suited to any ordinary case of illness. Nor can one deal in such a book as this with the methods of preparing food for the sick, or invalid cookery, no matter how important some acquaintance with that art must always be to the practical physician. In deciding upon the dietetic management of any case of disease it is important to bear in mind, what is often forgotten, that a patient is not a mere bundle of separate organs, but an organic whole, and that the diet must often be directed to the needs of the man rather than to those of his malady. The evil results of a forgetfulness of this fact are often seen. A patient's general nutrition may become seriously impaired, for instance, through well-intentioned efforts to lighten the labours of his stomach, or his heart may become enfeebled in consequence of a regimen designed to lessen the work of his kidneys. The important factor of idiosyncrasy must also be borne in mind, and full recognition made of the fact that different individuals react differently to the same diet just as they do to the same drugs. Nor must it be supposed, as the laity are apparently tempted to do, that diet is a universal panacea which can be counted upon to prevent or to cure all diseases. On the contrary, it has, like other remedial agents, only a limited place in therapeutics, and the few diseases which specially lend themselves to dietetic treatment may 480 FOOD AND DIETETICS be divided into the following groups: (i) Fevers; (2) disorders of metabolism, e.g., diabetes, obesity, gout ; (3) affections of the stomach and bowels ; (4) disorders of the circulation and blood ; (5) diseases of the organs of excretion. Before, however, one passes to the separate consideration of these groups, it is advisable to point out a few practical rules which should always be present to one's mind in drawing up any scheme of diet for a patient. They are these : 1. In acute disease it is well to recommend a special plan of diet; in chronic cases it is often more convenient simply to forbid those articles' which are likely to prove harmful. The next two rules are corollaries to the first. 2. Before recommending any article it is well to ascertain whether the patient likes it, and how it agrees with him. 3. No article should be forbidden unless one has good reason for doing so. 4. Unless there is some strong contra-indication, attention should always be paid to the wishes and tastes of the patient. This rule was first formulated by Hippocrates in the aphorism, ' Such food as is most grateful, though not so wholesome, is to be preferred to that which is better, but distasteful ' ; and Sydenham recognised its value when he wrote : ' More importance is to be attached to the desires and feelings of the patient, provided they are not excessive or dangerous, than to doubtful and fallacious rules of medical art.' 5. If any article of food disagrees, it is better to reduce the quantity of it taken than to cut it out of the dietary altogether. 6. Changes of diet should, if possible, be made gradually. 7. One should never prescribe a diet for a patient without having first ascertained what his habits are as regards work and exercise. These rules require no comment. 1. Principles of Diet in Fever. There are few departments of practical medicine in which opinion has undergone a greater revolution than in the question of fever diet. 1 Hippocrates fed his fever cases simply upon wine and ' ptisan,' or thin barley gruel, and this lowering plan, first practised for centuries on the sole weight of his authority, was afterwards endorsed by the erroneous pathological doctrine first promulgated by Broussais, that fevers proceeded from irritation of the intestinal 1 For a full account of the history of the subject, see J. Uffelmann, ' Die Diat in den Acut-fieberhaften Krankheiten,' 1877. FOOD IN FEVER 481 mucous membrane, and therefore demanded a starvation diet. His contemporary, Brown, though perhaps not much nearer the truth in his pathology, was better advised in his practice when he taught that fevers were ' asthenic ' diseases, and required to be treated by liberal feeding. It was not until about the middle of the present century, however, that Graves, discarding all pathological doctrines, and guided simply by the results of observation, came to the con- clusion that the popular starvation method was wrong, and intro- duced the modern practice, ever since adopted, of ' feeding fevers.' The prevailing system at the present time may be fairly described as that of feeding a fever patient up to the limits of his digestive capacity with fluid or semi-fluid food, except, perhaps, in the case of some abdominal fevers. The reaction against the starvation plan has, it will be admitted, gone, if anything, rather too far, and the danger now is that too much rather than too little nourishment may be given. Any lingering doubts as to the wisdom of the feeding plan tend to be dispelled by the results of recent research, which have shown (1) that the free administration of food does not, as was formerly supposed, tend to raise the temperature of feverish patients -, 1 and (2) that the food is not merely poured into a digestive apparatus unable to deal with it, for the absorption of light articles of diet, at any rate, goes on almost as perfectly in the febrile as in the non- febrile state. 2 Granted, then, that the liberal administration of food in fever is justified on grounds alike of experience and pathology, we have next to inquire, What nutritive constituents should the diet of fever chiefly contain ? A study of the metabolic changes in fever may be expected to afford us some light here. Extensive investigation into these changes in recent years has tended to show that the leading charac- teristic of the metabolism of fever is a great increase in the destruc- tion of nitrogen-containing tissues, while the mainly carbonaceous components of the body, such as fat, are affected in a much smaller degree. The reason for the increased destruction of nitrogenous tissues in fever appears to be twofold : Firstly, and probably mainly, it is due to simple inanition, to the fact that less food is reaching the tissues 1 Von Hoesslin, Virchow's Anhiv,, 1882, lxxxix. 95, 303. He found that in cases of typhoid the temperature on days when food was administered was only from- o - n° C. to 0-3" C. higher than on starvation days. a Ibid. See also Leyden's ' Handbuch der Ernahrungstherapie, ' p. 403. 3 1 482 FOOD AND DIETETICS than is required to meet their output of heat. In part, however, it seems also to be due to the fact that the ' toxins ' which produce fever exert a specially destructive influence on the proteid con- stituents of the body. This being so, it seems natural to suppose that the chief dietetic indication in fever must be to supply a large proportion of proteid in the diet. Actual observation, however, has shown that it is im- possible to bring about a condition of nitrogenous equilibrium in acute fevers on any feasible quantity of food. The reason for this probably is, that although one may cover the waste which is due to simple inanition, it is impossible to prevent that which is brought about by the destructive action of toxins on the cells. Practically, therefore, the administration of a large quantity of proteid in the diet fails to achieve the desired result, no matter how strongly it may be indicated theoretically. The consumption of much nitrogenous food has also this disadvantage, that it tends to flood the circulation with the products of nitrogenous waste, already too abundantly present, thus increasing the strain thrown upon the kidneys, and at the same time, in all probability, tending to bring about a condition of toxaemia, to which some of the symptoms of fever are no doubt due. We shall, therefore, better attain our object of limiting proteid destruction by seeing that the ' proteid-sparers ' are abundantly represented in the diet rather than by devoting too much attention to the proteids themselves. Now, the proteid-sparers, as we have seen, are, in order of their importance, gelatin, carbohydrates, and fats. The use of the first of these is restricted by the fact that the end-products of its de- struction are so similar to those of proteids that they may be expected to produce the same results as these in the circulation, while the employment of the last is rendered impracticable by the insuperable repugnance which feverish patients exhibit to fatty foods. We therefore arrive at the conclusion that the diet of fever should contain a liberal supply of carbohydrates. The contention that mineral matters should also be freely repre- sented — a contention based entirely upon theoretical grounds — has already been dealt with (p. 106). These being the dietetic indications derived from a study of the morbid metabolism of fever, we may next proceed to inquire how they may best be put into practice. And firstly, by common consent, the diet of fever is a fluid diet. This is not merely grateful to a thirsty patient, but evades the necessity of chewing, which the diminution of the salivary secretion FOOD IN FEVER 483 renders difficult. It has also the advantage of supplying much water to the tissues, of which in fever they seem to stand specially in need. Milk is the simplest, most accessible, and most nutritious of fluid foods, and should always form the basis of the diet. Four pints of it a day will supply about 1,700 Calories of energy to the body, and this, though quite insufficient for the needs of health, is usually enough to meet the demands of a patient confined to bed, especially in fevers of short duration, where the body can afford to draw to some extent upon its own resources. The milk may be given plain or diluted with some alkaline or effervescing water or lime-water. If the patient tires of it, it may be flavoured with a little cold coffee or with caramel or malt extract. If it produces vomiting or diarrhoea, it may be necessary to give it peptonized or to substitute koumiss. If less than 3 pints of milk can be got down in the day, nutrition is likely to become seriously impaired, and in that case it may be well to ' fortify ' the milk. The amount of proteid in it may be increased by the addition of such preparations as Casumen, Plasmon, or Somatose, or the proportion of fat may be raised by the addition of cream. For the reasons already given, however, it is better to enrich the milk chiefly by the addition of some carbohydrate. Of these milk-sugar is one of the simplest and best, and is probably not sufficiently made use of. One or two teaspoonfuls dissolved in a little hot water may be added to each tumblerful of milk. The value of sugar in fevers has been specially insisted upon by Fick j 1 and, of all forms of it, milk-sugar, from the comparative absence of sweetness which characterizes it, is probably best. Instead of using sugar, the milk may be enriched by the addition of some cereal preparation, such as oat-flour, arrowroot, or corn- flour, made in the form of a thin gruel. Many of the patent foods, such as Benger's, NestkVs, or Malted Milk, may here play a useful part, while some patients find the addition of malt extract agreeable ; a tablespoonful of it may be added to each ^ pint of warm milk. In any case, it is well to employ these different devices in turn, for patients quickly tire of any one of them. In addition to milk, soups, beef-tea, or broths may be allowed in the proportion of about 1 pint a day, but it should be remembered that their chief use is as exciters of appetite, and perhaps as slight stimulants, rather than as foods. They may also be made the vehicles for conveying carbohydrates into the body by thickening them with baked flour or some other simple farinaceous prepara- 1 Zeit. /. Klin, Med., 1886, x. 531. 31 — 2 484 FOOD AND DIETETICS tion, or with one or other of the patent proteid or carbohydrate foods. Where diarrhoea is present, tha use of soups, etc., containing meat extractives is better avoided. The consumption of beef-juices in fever, though very popular, is to be deprecated for the reasons given in another chapter (Chapter VI,); but the egg-white mixture already described (p. 102) may sometimes be a useful aid in cases where very little food can be taken at one time, and where vomiting is urgent. Jellies may also be allowed in moderation, those flavoured with wine being perhaps the best, but it must be recollected that their nutritive value is but small. As regards the intervals at which food should be given in fever, one must be guided chiefly by the digestive powers of the patient. It is well to begin with small quantities — say a wineglassful of milk — every hour or so, and gradually feel one's way till a tumblerful can be taken every two hours. Beef-tea can be given after every two of the milk-feeds, as a change. As far as possible the adminis- tration of food should be confined to the day hours, a little drink only being allowed during the night; but if the patient is much exhausted it may be necessary to feed by night also. Cold water is the best beverage in fever, but though the total amount of it need not be restricted, it is well only to allow a few sips of it at one time. The excessive consumption of aerated beverages is to be avoided, as tending to overdistend the stomach with gas. In addition to water, milk-sugar lemonade (a teaspoonful to the tumbler, flavoured with a squeeze of lemon-juice), fruit drinks — e.g., unfermented grape-juice or raspberry vinegar and water — or Imperial Drink, are all refreshing, and may be made the means of conveying some sugar into the stomach. Where there is any tendency to looseness of the bowels, however, it is well to restrict the drink to plain water or barley-water. A cup of tea or coffee may also be allowed if the patient desires it, especially in the early morning, and is probably too often forbidden without any sufficient reason. The use of alcohol in fevers is an important matter which calls for some special discussion. Hippocrates recognised the value of wine in fever, and since his time it has been pretty generally employed. Stokes of Dublin laid down certain imperative indica- tions for its use, and his colleague Graves devoted one of his clinical lectures to a consideration of the place which it should take in the general treatment of fever. The advantages of stimulants, however, ALCOHOL IN FEVERS 485 were insisted upon more strongly by Todd, 1 about the middle of the nineteenth century, than by any preceding English author, and the present general recognition of their utility is no doubt largely due to his almost too strenuous advocacy. Indeed, it may be questioned whether in this case also the reaction in favour of a ' stimulating ' treatment of fevers has not gone too far, and the administration of alcohol become too much a matter of routine. In a previous chapter we have learned that alcohol has a stimulating influence upon the heart, that it reduces body temperature by dilating the surface bloodvessels, and that it is in itself at the same time a source of energy, and diminishes tissue waste, especially the waste of fat. All of these properties mark alcohol out as an agent likely to be useful in the treatment of such a condition as fever. It would be a mistake, however, to suppose that it requires to be made use of in every case. Clinical observation has shown that it is only impera- tively demanded when the following indications are present : 1. Failing circulation, as exhibited (i)in a persistently rapid pulse (120 or more), or if it be weak, irregular, unequal, or dicrotic ; (2) by a faint or inaudible first sound of the heart. 2 2. Nervous exhaustion, as manifested by sleeplessness, low delirium, and tremors. 3. Failure of digestive-power, as indicated by inability to take food, diarrhoea, and dryness of tongue. 4. High temperature, especially if persistent. 5. A bad general condition — e.g., in feeble, exhausted, elderly, or alcoholic subjects. In some special diseases — e.g., malaria, erysipelas, and septic poisonings, alcohol seems to increase the resisting-power of the patient and is almost always indicated on that account. The form in which alcohol should be given in fevers is not a matter of indifference. If one merely wishes to obtain its effects upon the temperature and circulation, any pure form of spirit will do. Sound malt whisky is as good as any other. Where, however, there are signs of nervous exhaustion — as, for example, in the ' typhoid state ' — a preparation rich in volatile ethers should be selected. Of these genuine cognac is one of the best, and it is worth while to pay a high price for it in order to be sure of having it good. The ordinary so-called brandy is no better than whisky. Possibly the Spanish 1 ' Clinical Lectures on Certain Acute Diseases,' London, i860. Lecture XIV., ' On the Therapeutical Action of Alcohol.' 2 See Stokes, Dublin Med. Journ. (1st series), 1839, xv. 1. 4^6 pooD AND DlETEtlCS brandy recently introduced may prove useful, as it is said to be rich in ethers. Failing good brandy, one may fall back on one of the stronger wines, and of these old sherry is more highly ethereal than any other. 1 In catarrhal conditions, and where a tendency to vomiting is present, an effervescing wine, such as good, dry champagne, often gives the best results. In some forms of delirium, on the other hand, such as that due to alcoholism, bottled stout seems to exert a peculiarly sedative influence. In deciding upon the amount of alcohol to be given, and the frequency of its administration, one must be guided chiefly by the urgency of the indications calling for its use. Half an ounce of spirit, diluted with twice as much water, or an ounce of one of the stronger wines, may be given every four, three, or two hours, according to the effect produced, or even every hour if occasion demands it. Careful observation of the case will generally show whether the right amount is being administered. As long as the pulse is becoming slower and steadier, the skin and tongue more moist, the appetite better, and the patient quieter and calmer, the alcohol is doing good. The results of excessive dosage will usually first manifest themselves in the digestive organs in the form of flatulence, eructation, and dryness of the mouth, with the appearance of sordes on the lips. A tendency to coma, and a persistent smell of alcohol in the breath, are also signs that too much is being given. Diet in Special Fevers. The principles of diet described in the preceding pages are applicable to the majority of cases of fever, but in some one requires to introduce modifications. As has already been mentioned, the use of beef-tea and all fluids containing the extractives of meat is best avoided in cases in which there is diarrhoea. The same holds good for rheumatic fever. In that disease preparations derived from meat are generally held to be injurious, and the diet during the height of the attack should consist of milk alone or diluted with some alkaline water. Alcohol, also, is usually unnecessary, and to be avoided in these cases. The dietetic treatment of typhoid fever is described in so much detail in all text -books of medicine that it need not be fully described here. It is sufficient to point out that the majority of observers are in favour of a strictly fluid diet, consisting mainly of milk, in that 1 See Anstie, ' On the Use of Wines in Health and Disease,' p. 44 ; London : Macmillan and Co., 1877. DIET IN TYPHOID FEVER 487 disease, and many recommend that even milk should not be allowed in large amount, but that whey should be used in its place. If curds appear in the stools the milk should be peptonized, but if the case is running a favourable course the nutritive value of the diet may be increased by the addition to the milk of Plasmon or Casumen, Arrowroot, Maltine, biscuit powder, or one of the infant foods. Tea or coffee may be allowed in moderation, and the monotony of the diet varied by the addition of beef -tea fortified by a little Somatose. In prolonged cases vegetable soups and fruit juice should be allowed, in order to insure the supply of a sufficient quantity of potash salts to the blood. Where there is much tym- panites it is well to substitute whey for milk. It is difficult to justify the conventional strict diet of enteric fever on any grounds other than those of experience. The widely-spread impression that solids are injurious on account of the danger of their irritating the intestinal ulcers, and predisposing to haemorrhage and perforation, can hardly be defended, for, as we have already seen (p. 431), the intestinal contents, by the time the lower end of the ileum is reached, are always in a fluid form. In recent years a revolt against the orthodox practice has taken place, and a more abundant diet has been advocated, the extremest supporter of the new view being the Russian physician Bushuyez. The diet which the latter has adopted is certainly an extremely liberal one. The following is the scheme of it : 7 a.m. : Tea and a roll. 8 a.m. : 14 oz. of gruel (oatmeal, barley or wheat) with butter. 9 a.m. : One or two boiled eggs. 10 to 11 a.m. : A glass of milk, a roll, half a cutlet, and a bit of boiled meat. 12 to 12.30 p.m. : A bowl of soup and a little jelly. 3 p.m. : Tea and a roll. 6 p.m. : A cup of soup, a bit of chicken, and milk pudding. 8 p.m. : A roll and milk. During the night coffee or tea, with milk, is allowed several times. In 318 cases in which this diet was adopted the mortality was only 8-2 per cent. ; not a single case was lost from haemorrhage, while the general condition of the patient was much better than that of those fed on the orthodox lines. All the patients were allowed to sit up in bed, and many were able to walk a little. A paper by Dr. Morris-Manges 1 contains a full account of the results yielded by the new diet. The writer himself used a diet consisting of milk, soft-boiled eggs, custard, jellies, chicken, rice, baked potatoes, and strained cereal gruels, in eight cases. He states 1 New York Medical Record, 1900, Ivii. 1, 488 FOOD AND DIETETICS that the stools were always well digested, that the diarrhoea was not increased, and that subsequent emaciation and anaemia were very slight. He had 25 per cent, of relapses, but this, as he points out, is much higher than that found by Bushuyez and others in a much more extended series of cases. Vaquez 1 in France, Strouse 2 in America, and, in this country, Barrs, 3 Marsdeh, 4 and F. J. Smith 5 also advocate the more liberal diet, and report good results from its adoption. The present writer's own belief is that here, as in most forms of illness, one must individualize, and that whereas in some cases the patient may be intolerant even of diluted milk, and must be fed exclusively on whey and grape-juice, yet there are many cases in which the administration of semi-solid, or even solid, food is justi- fiable at an early stage of the disease. In every case, of course, insoluble vegetable articles, such as the skins and pips of fruit, currants, etc., should be rigidly withheld, but such things as lightly- cooked eggs, custards, rusks, milky puddings, bread-sauce, and crisp toast are often quite admissible, and undoubtedly help to maintain strength and nutrition, and to shorten convalescence. If a patient expresses a wish for such foods it is usually safe to conclude that they will not harm him. Cushing and Clarke 6 recommend the administration of large quantities of water (a gallon or more in twenty-four hours) in typhoid fever. This is easily managed if given in small quantities at frequent and regular intervals. They find that patients are more comfortable on this mode of treatment, and that toxic nervous symptoms are lessened. They regard it as a valuable adjunct to the cold bath. 2. Disorders of Metabolism. Diabetes. Whatever view one may hold as to the true pathology of diabetes, there is almost universal agreement as to the value of restricting the intake of carbohydrates in that disease. It may be objected that, even if one succeeds in doing this to the point of causing all sugar to disappear from the urine, one has thereby only masked the most prominent symptom of the disease, without in any way striking at the root of the complaint. To this it may be replied : 1. That clinical experience has shown that in many cases, by with- 1 La Presse Med., i960, viii. 73. 3 Amer. Joum. of Med. Sciences, 1909, cxxxvii. 631. 3 Brit. Med. Journ., 1897, i. 260. 4 Lancet, 1900, i. 90. 6 Brit. Med. Journ., 1906, ii. 1014. 6 Amer. Journ. of Med. Sciences 1905, cxxix. 187. DIET IN DIABETES 489 drawing all carbohydrates from the diet for a time, one can succeed in re-educating the tissues in their power of dealing with sugar, at all events to some extent, and that a return to an ordinary diet is then no longer accompanied by a corresponding increase in sugar excreted. 1 2. Even were it the case that limitations of carbohydrate ingestion had no truly curative influence, there can be no doubt that many of the most distressing symptoms of which diabetics complain, and most of the complications which may cut short their lives, are due, not to the disease per se, but to the presence of an excess of sugar in the circulating fluids. It being granted, then, that limitation in the carbohydrates in the diet of diabetes is justified, one has next to ask : How are they to be replaced ? The importance of this question will be obvious when one reflects that most people are in the habit of obtaining at least one-half, and sometimes even three-fourths, of their total daily supply of energy in a carbohydrate form. Obviously, then, some other source of energy must be found, unless one's patient is to be starved to death, and practically one has to choose as the substitute for carbohydrate either proteid or fat. As to the relative merits of these two substitutes, there is not much difficulty in coming to a decision. Fat is a com- pact source of energy, and yields, for a given weight, two and a quarter times as many Calories as proteid. In all probability, too, it cannot act in itself as a source of sugar. Proteid, on the other hand, is more bulky and can certainly produce sugar. In addition to this fat can, to a considerable extent at least, fulfil the proteid- sparing function of carbohydrates, and is thus in every way calculated to serve as a substitute for these in the food. 2 We conclude, then, that richness in fat must be the leading characteristic of a rational diabetic diet. The next question which arises is this : To what extent are the carbohydrates to be restricted ? Are they to be abolished from the diet altogether, or only reduced in quantity ? Before a reply to this question can be given, one must ascertain the severity of the case with which he has to deal, for in some the tissues have lost their power of assimilating carbohydrates completely, while in others that power has only undergone impairment. 1 For evidence bearing upon this point, see Von Noorden, Leyden's ' Handbuch der Emahrungstherapie,' p. 442. 2 I am aware that Dunlop ('Dietetic Value of Fat in Diabetes,' Edin. Med. Journ., 1896, xlii. 399) has advanced evidence in one case to show that fat does not exert its usual proteid-sparing action in diabetes, but the bulk of the clinical evidence available is opposed to such a conclusion. 49° Pood and dietetics In order to discover to which of these classes the patient belongs, he must be put on a test diet containing a known quantity of carbo- hydrates. The test diet should consist of i pound of meat, three eggs, green vegetables, and butter, with the addition of 4 ounces of bread, 1 part of which should be eaten at each meal. If sugar disappears completely from the urine on such a diet, the case is evidently a mild one ; if, on the other hand, the urine only becomes sugar-free when the bread in the diet is reduced in quantity or altogether abolished, the patient has obviously a small degree of tolerance for carbohydrates, and the case is one of medium severity ; whilst if sugar persists in the urine even after all bread has been omitted, and especially if the aceto-acetic acid reaction is present, one is dealing with the severe type of the disease. The subsequent regulation of the diet must be determined by the class of case to which the particular patient belongs. If he can take 2 ounces of bread without glycosuria resulting, he may be allowed 1^ ounces or its equivalent in some other carbo- hydrate-containing food. If 3 ounces of bread are borne, allow only 2 or o\ ounces or its equivalent, and so on. It is never safe to feed a patient up to the limits of his tolerance. If, on the other hand, sugar disappears from the urine on the strict diet, but reappears whenever the smallest quantity of carbo- hydrate is added, his diet must consist exclusively of proteid and fat. In the third class of case, that in which sugar continues to be excreted even on a carbohydrate-free diet 2 — and to this class most of the diabetics seen in hospital practice seem to belong — then a some- what different method of procedure is called for. It is not wise to restrict the carbohydrate part of the diet in such cases too rigidly, especially if the aceto-acetic acid reaction is present in the urine. Experience has shown (1) that although in such cases a restricted diet may reduce the amount of sugar in the urine, yet the general condition of the patient suffers, and he is apt to lose weight ; (2) that, strange though it may appear, a few at least of these cases actually excrete more sugar on a diet rich in proteid than on one in which part of the proteid is replaced by carbohydrate. 8 In the opinion of 1 Four ounces of bread yield 66 grammes of sugar. 2 The term ' composite diabetes ' has been applied to such cases by Dr. Pavy. 8 Even where everything is going well, it is not advisable, when one is dealing with this type of the disease, to give more than 500 grammes (18 ounces) of cooked meat a day, or its equivalent in other forms of nitrogenous food. The author's own practice is to give 6 ounces of cooked meat, 2 pints of sugar-free milk, 3 eggs, and 4 ounces of casoid-meal bread daily. If the sugar excretion does not fall, or if the patient loses weight, or if coma threatens, a weighed quantity of ordinary bread is added. PROTEID AND FAT IN DIABETES 491 many good observers, too, such patients are more apt to develop diabetic coma on a very strict diet than on one which is more lax ; this, however, may only be true where the carbohydrate is chiefly replaced by proteid rather than, as it should be, by fat. There is also the practical difficulty that in the cases belonging to the last group proteids must be so much restricted that an enormous consumption of fat is necessitated if nutrition is to be adequately provided for, and it is difficult to persuade the patient to take the necessary quantity unless some carbohydrate (such as bread or potato) is allowed as a vehicle for carrying the fat. Summing up what has been said above, one may conclude : 1. That in mild cases of diabetes the diet should contain a some- what greater amount of proteid than normal, along with a large proportion of fat and as much carbohydrate as can be tolerated without the appearance of sugar in the urine. 2. In the more severe cases in which, on a carbohydrate-free diet, the sugar disappears, but comes back again whenever any starchy food is taken, the diet should resemble the above, but should contain an extra quantity of fat. 3. In the severest cases of all, in which sugar is excreted in the urine even although there be no carbohydrate in the food, the diet should consist of a somewhat smaller proportion of proteid than normal, along with a small amount of carbohydrate and as much fat as the patient can be induced to digest. It will be evident from these considerations that there is no such thing as ' a diabetic diet.' Every case of the disease must be treated on its merits, and any routine system of diet is to be carefully avoided. We may now consider in greater detail what foods are available as sources of each constituent. 1. Proteids. — -With regard to these there is no difficulty. The patient has the whole animal kingdom to choose from, though, in cases where a very strict diet is being enforced, it is well to avoid such articles as oysters, liver and sausages, all of which contain, or may contain, some carbohydrate. As a rule, the fatter meats and fishes are to be preferred to the leaner. Of milk products, cheese may be allowed in every case, and Devonshire cream may also be regarded as harmless. The use of milk itself will be considered more fully immediately. 2. Fat. — The best sources of fat are butter or margarine, bacon, the fatter meats (e.g., pork), and fish (e.g., eel, mackerel, and sardines in oil), suet, dripping, salad oil, eggs, cheese and thick cream. Of 492 FOOt) AND DIETETICS these butter should always be largely represented in the diet. There should be no difficulty in getting a patient to eat J- pound of it in the day, and in some cases one can get down 6 ounces, or even more. If a small quantity of carbohydrate is allowable in the diet, the administration of fat is much facilitated, for the carbohydrate- containing food can be made use of as a carrier of fat. Thus, toasted bread may be soaked in butter or bacon-fat, or potatoes may be made into a pur6e with butter and cream. A given quantity of mashed potato, if cooked by steam, should easily take up half its weight of butter and a quarter of its weight of thick cream. If carbohydrate foods are rigidly excluded, one has more difficulty in persuading the patient to swallow an adequate quantity of fat. In such a case green vegetables must be our chief resource as a fat-carrier. Mashed greens, from which the water has been removed as far as possible by squeezing in muslin, should easily take up one-third of their weight of fat, and salads can be covered with about one-fifth of their weight of oil without becoming unduly greasy. Eggs, too, can be made rich in fat by ' scrambling ' them with plenty of butter, and melted butter can be used as a sauce for white fish. By these devices, and by the liberal use of fat bacon, thick cream and cheese, one can usually get down a sufficiency. It is worth remembering that the use of alcohol at meals greatly aids the digestion of fat, and some writers recommend the administration of chalk (30 grains thrice daily) with the same object. I have certainly seen cases where this seemed to make the fat better borne, but it is apt to produce constipation, which of course is a thing to be carefully avoided in diabetics. In some cases it may be necessary to have recourse to the administration of cod-liver-oil in order to supplement the fat of the diet, but as far as possible this should be avoided. Petroleum emulsion, which is sometimes recommended for a similar purpose, is, as the writer has shown elsewhere, perfectly useless as a food. 3. Carbohydrates. — The following table, which shows (approxi- mately) the percentage of carbohydrates in some of the commoner foods, may be of help in making a selection : CARBOHYDRATES IN FOODS 493 APPROXIMATE PERCENTAGE OF CARBOHYDRATES IN SOME FOODS. Milk Products. Carrots IO'O Leeks 5-8 Cow's milk . . . . 4'5 3 "3 i'5 3"o 1 '5 ,, (cooked) . . 30 Tomatoes 5'° Butter-milk Turnips 5"o Vegetable marrow Koumiss Cream Devonshire cream . . , , (cooked) . . Radishes Beetroot (cooked) .. Parsnips • , , (cooked) . . 0-6 4-6 no (cooked) Fruits. 02 Cereals. 2'8 14-0 Apples and pears . . Stone-fruits 10 120 to 15 White bread 500 i - 4 Gooseberries (ripe) 90 Oatmeal and rolled Artichokes . . , , (cooked) Onions 14-6 (green) 20 oats 65-0 760 46 6'3 Currants Strawberries 80 6-o „ (boiled) 400 Vegetables. Raspberries Cranberries 5'o 4-0 Pulses. Cabbage (cooked) . . °'4 Grapes 150 Green peas i6'o Sprouts 3'4 Melons 7'o Dried 55"° Lettuce 2-6 Bananas 220 French beans 70 Spinach (cooked) . . o-8 Oranges (ripe) 8-9 Revalenta 65 Water-cress 37 „ (young) . . 2'0 Soy beans 28-0 Cauliflower.. 47 Pineapples 9'5 Peanuts 17-0 Asparagus 2-9 Cucumber . . 21 Nuts . . 9 to 12 Roots and Tubers Rhubarb 2-3 Almonds io'O Potatoes 200 Celery 3 - 3 Chestnuts . . 40 - o Green vegetables contain so little carbohydrate that they may be allowed in every case. Asparagus, celery, young rhubarb, tomatoes, vegetable marrow, cucumber and mushrooms may also be regarded as harmless, but carrots, beetroot, and parsnips should be avoided. Cereals and pulses are, of course, inadmissible, and if the richer carbohydrate foods are allowed at all, bread and potatoes should usually be selected, as the deprivation of these is always keenly felt by the patient. It is important to remember that potatoes contain only about one- third as much starch as bread, and so may be given much more freely than the latter. If, for instance, a patient is capable of taking 2 ounces of bread daily, he may be allowed 6 ounces of cooked potatoes instead, if he prefers it. As the fat-carrying power of potatoes is so great, such a substitution is often an advantage. The statement sometimes made, however, that potatoes are harmless if not actually advantageous in diabetes 1 is certainly erroneous. Of fruits, green gooseberries, early oranges, cranberries, and raspberries are usually permissible, and are best stewed with saccharin and eaten with thick cream. All sweet and dried fruits must be avoided. 1 See a paper by Sir James Sawyer (' Improvements in Dietetics of Diabetes '), Brit. Med.Journ., 1904, i. 537. 494 FOOD AND DIETETICS If one wishes to use other carbohydrate foods instead of bread, the following equivalents are worth bearing in mind : 2 oz. of bread contain as much carbohydrate as 2 oz. of pea or lentil flour. 2 oz. of bread contain as much carbohydrate as i^, oz. of rice. 2 oz. of bread contain as much carbohydrate as ij oz. of oat, barley, or maize flour. 2 oz. of bread contain as much carbohydrate as if oz. of cornflour, arrow- root, sago, tapioca, or rice flour. 2 oz. of bread contain as much carbohydrate as 10 to 15 oz. of the sweeter fruits. 2 oz. of bread contain as much carbohydrate as 40 oz. of apples. Iceland and Irish moss, which are often recommended for diabetics, are, as has been shown elsewhere (p. 268), almost entirely devoid of nutritive value. The Cheltine 1 and Manhu Foods 2 contain just as much carbo- hydrate as the corresponding wheat products, and the claim that the starch in them has, by a special method of preparation, been rendered comparatively harmless cannot be admitted. 4. Albuminoids. — The use of gelatin is quite permissible in all cases of diabetes, but the amount of nourishment which can be obtained in that form is very small. Jellies, of course, must be made without sugar. They can be flavoured with wine and sweetened with a little saccharin. Some Special Articles of Food in Diabetes. 1. Milk. — Opinions differ as to the place which milk should occupy in the dietary of diabetes. The real question is whether or not milk- sugar is capable of assimilation by diabetics. Some authors have asserted that it is, and Donkin 3 even went so far as to recommend a purely skim milk diet in diabetes, and has recorded some apparently excellent. results from that plan of treatment. He states that such a regimen either greatly reduces or even altogether banishes the sugar in the urine. He is careful to point out that if cream or butter or any nitrogenous food is taken at the same time one does not get these effects. The maximum quantity allowed was 12 pints a day, and he insists that the milk should be fresh, not boiled. Whilst some of the results recorded by Donkin are very striking, it must be admitted that other observers have failed to confirm them, although recently Winternitz and Strasser have reasserted the 1 The Manhu Food Company, Ltd., 23, Blackstock Street, Liverpool. 2 The Cheltine Food Company, Cheltenham. 3 ' On the Relation between Diabetes and Food '; London : Smith, Elder and Co., 1875. MILK IN DIABETES 495 value of the treatment, even in severe cases. 1 On the other hand, experiments made by the subcutaneous injection of sugars in diabetes have failed to show that lactose is assimilated in that disease. 2 Whatever the ultimate opinion as to the value of an exclusively skim milk diet in diabetes may be, there is pretty general agreement that the addition of milk to an ordinary dietary in diabetes causes a considerable increase in the amount of sugar excreted. The following case, that of a middle-aged man with a severe form of the disease, may serve as an illustration : Diet. Urine. Sugar. Meat and fat + 3 oz. of bread . . . . 1,500 c.c. 60 grammes. Meat and fat + 3 oz - of bread and 3 pints of milk 2,820 ,, 125 ,, It is true that, even although the amount of sugar is increased, the patient often feels better and his weight rises when milk is allowed, and on that account many observers advocate its presence in the diet. Fortunately, however, one can easily obtain all the advantages of milk without its disadvantages by getting rid of the sugar which it contains, while leaving the casein and fat. One then gets what may, for convenience, be termed sugar-free milk. Methods of preparing such milk have been described by Wright 3 and by Ringer, 4 while a very similar fluid, the chief ingredients of which are cream-fat and egg-white, has been elaborated by Williamson ; 5 in Germany, also, Von Noorden has advocated the employment of a similar artificial milk. 6 With the assistance of Mr. Morris, formerly Chief Dispenser to the London Hospital, the author has succeeded in preparing a modified milk which contains merely a trace of sugar, and which has given excellent results in several cases. 7 The follow- ing are the directions for making it : 1 Centralb. f. Inn. Med., 7899, xx. 1137. 2 Achard and Weil, Archiv. Jc Med. Expir., 1898, x. 816. 3 Brit. Med. Journ. , 1891, i. 787. 4 Ibid., 1895, ii. 14, 12 ; 1524. 6 ' Diabetes Mellitus,' p. 334 ; Edinburgh and London : Young J. Pentland, 1898. " Leyden's ' Handbuch der Ernahrungstherapie,' p. 475. 7 Sugar-free milk is now made by Clay, Paget and Co. according to the above formula, and can be obtained through Messrs. Callard, Regent Street, W. It contains about 8 per cent, of proteid and 7 per cent, of fat, and 2 pints of it yield 1,120 Calories, or nearly half the total amount of energy required by a patient at rest in bed. A$ FdOb A Kb blEfEtlCS Sugar-free Milk for Diabetic Feeding. Take I litre of skim milk, heat to a temperature of 38° C, and add 10 c.C. of glacial acetic acid, diluted with 100 c.c. of water. Mix, and allow the mixture to stand for about fifteen minutes. Collect the separated casein, and let it drain on very fine muslin, using no pressure. Remove the casein to a mortar, rub into a smooth paste, add \ litre of dis- tilled water, and strain as before. Repeat this washing of the casein twice. Transfer to a mortar, rub until quite smooth, and add 25 grammes of potassium hydrate dissolved in 100 c.c. of water (or as much of the KHO as is necessary to make the product just alkaline to phenolphthalein). Add 100 grammes of ordinary Devonshire clotted cream, 5 grammes of gelatin, previously dissolved, '06 gramme (1 grain) of saccharin, and water, at about 38° C, up to 1 litre. Lastly, strain through fine muslin. The product tastes very much like ordinary cow's milk, and can be taken either plain or with some effervescing water, or it can be added to tea or coffee or made into custards with eggs. In some cases as much as 5 pints of it have been taken in one day, and it does not seem to have any appreciable effect in increasing the output of sugar. In one case a patient on very strict diet excreted 1,000 c.c. of urine daily containing 22 grammes of sugar. On 5 pints of ' diabetic milk ' and four eggs he excreted 1,630 c.c. of urine with 28 grammes of sugar. Another patient on a fixed diet containing a known quantity of carbohydrate and 1 pint of ordinary milk excreted 3,350 c.c. of urine with 180 grammes of sugar. When the ordinary milk was replaced by diabetic milk, the quantity of urine fell to 2,450 c.c, and the sugar to 125 grammes. The use of such a milk will be found to be a very great aid in feeding diabetics, especially when they are unable to take much meat. Of milk products, cream can usually be allowed to diabetics, and the thicker it is the better. Devonshire cream is a specially valuable form. Junket, on the other hand, contains a considerable quantity of sugar, and is best avoided. Koumiss and kephir, though contain- ing considerably less sugar than ordinary milk, are still fairly rich in it, and should be forbidden in any case in which the diet requires to be at all strict. 2. Diabetic Breads. — In recent times a large variety of breads have been specially devised for the use of diabetics. For the most pari these are compounded of eggs, along with some vegetable substance more or less free from starch. Of such substances, gluten, the chief proteid of wheat, was one of the first to be employed, 1 but more recently the oily nuts (such as the almond, cocoa-nut, and hazel-nut), bran, and the soja bean, have also been pressed into the service. 1 See Bouchardat, Comptes Rend., 1841, xiii. 943, DIABETIC BREADS 497 Of these products it may be remarked, in the first place, that many of them — and this applies specially to the gluten breads — are by no means free from starch ; l while in the case of others the chiet ingredient is cellulose, which, of course, yields no nutriment to the body. Indeed, the only really valuable substance which they con- tain is fat, of which the bread may be regarded as a carrier. This is especially true of the almond and nut breads. Bran, being incapable of digestion in the human intestine, can serve no other purpose than that of adding to the bulk of the diet. This fact, that the greater part of many diabetic breads is composed of wholly non-nutritive matter, has not, I think, received the attention which it deserves. In addition to these objections, one may say of all ' diabetic breads ' that they are very expensive, and of most of them that they are extremely unpalatable, and that patients quickly tire of them. In recent times casein has been adopted as a basis for diabetic breads ; ' Protene Diabetic Bread,' 2 ' Casoid Bread,' 3 ' Casoid Meal Bread,' 3 Prolacto Bread, 3 and Casein Bread 4 are examples, and are entirely free from carbohydrates, besides being fairly palatable. Plasmon Diabetic Biscuits, Biogene Wafers (Bonthron), and ' Akoll ' Biscuits (Huntley and Palmer) are also starch-free. Home-made diabetic breads may be prepared from such substances as Roborat (p. 220),. Aleuronat (p. 561), Glidine (p. 220), Protene, Plasmon, Biogene, etc., along with almond-flour and cocoa-nut powder. The same ingredients may be used for making puddings and cakes. 6 It may be well to point out here that the widely-spread belief that toast is less harmful to diabetics than bread is quite erroneous. Weight for weight toast contains more starch than bread, and is therefore more instead of less harmful than the latter. 3. Special Forms of Carbohydrate in Diabetes. 6 — Of all forms of carbohydrate, grape sugar is less perfectly assimilated by diabetics than any other. Next to it come starch and cane-sugar, the latter of which is always to be avoided. Inulin is said to be well borne in 1 It is easy to test any of these breads by letting fall on to the cut surface a drop or two of iodine solution ; a deep blue-black coloration reveals the presence of starch. 2 Protene Co., 36, Welbeck Street, W. 3 Callard and Co., Regent Street, W. * Bonthron, 50, Glasshouse Street, W. 6 Recipes and directions will be found in such books as W. H. and Mrs. Poole's ' Cookery for the Diabetic ' (London, 1903), Callard's ' Guide to Diabetic Cookery,' Senn's 'Manual lor Diabetic Diet and Cookery' (sold by Bonthron and Co.), and Dr. R. T. Williamson's ' The Articles of Food Suitable for Diabetic Patients ' (Sherratt and Hughes, 1909). 6 See Achard and Weil, Archiv. de M4i. Exptr., 1898, x. 816, and Von Noorden, op. at., p. 454. 32 498 FOOD AND DIABETIC mild cases, but is not of much, practical dietetic importance. It is present in small amount in the Jerusalem artichoke and other Com- positae. The assimilation of lactose has already been referred to. Much discussion has taken place as to the value of lasvulose for diabetics. 1 While the earlier reports of its utility were considerably exaggerated, there is no doubt that diabetics utilize it better than any other form of carbohydrate. The chief importance of laevulose is as a constituent of fruits, in which it is sometimes the principal carbohydrate present. Early, sour oranges, for example, contain only 2 to 3 per cent, of carbo- hydrate altogether, of which laevulose is the chief; and even sweet oranges have not more than 5 to 7 per cent. 2 For that reason their use may be permitted in some cases. Other fruits poor in carbo- hydrates are strawberries, gooseberries, apricots, and rrielons. In the form of compotes, sweetened with saccharin, they may be useful in some cases. Nuts, being practically devoid of carbohydrates other than cellulose, while rich in proteid and fat, may be allowed in almost every case. Beverages in Diabetes. The great thirst complained of by most diabetics demands the free use of beverages, and, fortunately, there is no reason to suppose that these do any harm, provided they be properly selected. Much the same remarks apply here as in the case of fevers. Water is the best beverage, while the aerated waters should be indulged in more sparingly. Citric acid lemonade (10 grains to the pint, sweetened with £ ounce of glycerine or a little saccharin) is also a pleasant thirst-quencher. Tea and coffee may be allowed freely, and may be taken with diabetic milk, and sweetened with saccharin if preferred. Cocoa, though often forbidden, contains so little starch that it is not likely to do harm. Of course, pure cocoa should alone be selected. It also may be made with diabetic milk. Alcoholic beverages are extremely useful, and one can rarely afford to dispense with them altogether. Alcohol is not merely in itself a valuable food in diabetes, acting both as a source of energy and as a sparer of proteid and fat, but it has also the further advan- tage of aiding greatly in the digestion of fat, of which, as has been so often insisted upon, every diabetic must freely partake. Under its 1 See Hale White and Grube, Zeit. f. Klin. Med., 1894, xxvi. 332, 2 JCraus, Zeit. f. Didt. und Ptysik. Therapie, 1898, p. 6g. ARRANGEMENT OF MEALS IN DIABETES 499 use the output of sugar and nitrogen is lessened, whilst the pro- duction of acetone is also decreased. 1 With the exception of malt liquors, 2 liqueurs, and sweet wines, almost any form of alcoholic drink may be allowed. In cases where a very stringent diet is being enforced, recourse may be had to one or other of the sugar-free alcoholic drinks, a list of which has been given elsewhere (see foot- note, p. 394). If the patient is gouty as well as diabetic, alcohol is better avoided. Arrangement of Meals in Diabetes. As diabetics usually suffer considerably from hunger, it is well to make the meals rather frequent. Where a limited quantity of carbohydrate is allowed, it will be found convenient to adopt the suggestion put forward by Von Noorden, and arrange that each meal shall consist of one principal dish and an ' extra ' in which the allowance of carbohydrate is con- tained. For example, in a severe case in which 2 ounces of bread and 2 ounces of potato are being allowed, the diet may be made up of the following constituents : Meat . . 4 oz. Eggs •• 4 Diabetic milk . . . . 2 pints Fish Butter ■ • 6 „ Green vegetables . . 2 ,, Divided into meals, this would work out as follows : Breakfast. Chief dish : Bacon and a scrambled egg. Extra : 1 oz. of bread, toasted with plenty of butter. Tea with diabetic milk and saccharin. J pint of diabetic milk. Dinner. Chief dishes : Meat (4 oz.), green vegetables and butter. Custard pudding, made of diabetic milk and 2 eggs. Extra : Potatoes (2 oz.) and plenty of butter. Water, spirit and water, or some dry wine. Tea. An egg : bread (1 oz.), plenty of butter. Tea or coffee with diabetic milk and saccharin. Supper. Fish (2 oz.) with butter sauce. 1 pint of diabetic milk. 1 See Benedict and Torbk (Zeit. f. Klin. MM., 1906, lx. 329). 2 A sugar-free ?.le is sold by Messrs. Harvey and Co., Grove Brewery, t-uddenden Foot, S.O. , which diabetic patients may safely take. 32—3 500 FOOD AND DIETETICS This diet contains about 85 grammes of proteid and 225 grammes of fat, not reckoning the carbohydrate, and has an energy-value of about 2,500 Calories. By the use of some alcoholic drink at dinner and supper the value of the diet could easily be raised to 3,000 Calories, and upon this most cases will be found to gain weight. In milder cases, for which more proteid is advisable, one can easily double the quantity of meat or fish, and the proportion of fat can be raised by the use of thick cream in tea, and its addition to mashed potatoes. In cases in which a strict diet is being enforced, one can replace the bread and potatoes by an extra allowance of milk and eggs and a more liberal use of alcohol. In mild cases in which there is a considerable tolerance for carbo- hydrates, the quantity of fat in the diet can be considerably reduced. It need hardly be said that the above diet is merely given as a sample ; its proteid and fat containing ingredients may be varied very greatly according to the taste of the patient. It will be found, however, I think, to be well suited for routine hospital use. Even in mild cases with a considerable tolerance for carbohydrates, Von Noorden recommends that the patient should be subjected at intervals of a year or so to a short course of very strict diet. He believes that in this way the power of the cells to assimilate carbo- hydrate may be conserved. If coma threatens or has set in, it is best to abandon the strict diet, and to feed the patient mainly on skim milk 1 and Vichy water, with a liberal use of alcohol. The dietetic treatment of the so-called gouty glycosuria met with in elderly people is essentially the same as that of true diabetes. It is impossible, indeed, to draw any sharp line of distinction between the two conditions except, that whereas the glycosuria of young subjects is not only persistent but progressive, that of older people, though it may persist, often does not tend to increase — *'.«., there is no pro- gressive failure of assimilation going on as there is in true diabetics. 1 Skim milk is preferable to ordinary milk, for there is some reason to suppose that the presence of fat in the diet favours the production of acetone (see a paper by Dr. F. Schuman-Leclercq in the Dublin Journal of Medical Science, igoi.cxii. 161, entitled 'The Influence of Food on the Excretion of Acetone'). A case of acetonuria in which acetone disappeared when the amount of fat in the diet was reduced has also been recorded by Pollatschek (Zeit. f. Dial, und Physik. Therapie, 1904, viii. 163-165). Lenne, however (ibid., 1904, viii. 253), brings forward evidence opposed to the view that the amount of fat in the diet has any influence in the production of acetonaemia. The whole subject is discussed in detail by Bosanquet, Goulstonian Lectures, 1905 (Lect. III., Lancet, 1905, i. 1053). btABkTic Coma $& Most of these cases will be found to have a considerable tolerance for carbohydrates, and all that is necessary is to keep the supply below that limit. Should the tolerance be nil, the case must be managed on the same lines as one of true diabetes. Alcohol, it should be remembered, is often injurious in the glycosuria of elderly persons, particularly when there is coexisting obesity or renal disease. It will be found a great advantage to begin the treatment of all cases of diabetes either in hospital or in a Nursing Home. The patient is then under strict supervision, and it is much easier to determine the exact nature of the case with which one has to deal. In addition to this, the discipline to which the patient is subjected has a wholesome influence upon him, and serves to educate him in methods of dieting himself when he returns to his ordinary life. It only remains to point out that a dietary suitable for diabetics is necessarily an expensive one, from the fact of its consisting mainly of animal food and fat, and this will be found to be a great obstacle to the proper treatment of diabetes amongst the poor. In many cases there is room here for charitable aid in enabling the patient to get abundance of such articles as butter, cream, and meat, without which proper treatment of the case is impossible. £502 J CHAPTER XXVIII THE PRINCIPLES OF FEEDING IN DISEASE {continued) The Dietetic Treatment of Obesity. The occurrence of obesity is almost invariably an indication of a disproportion between the intake of potential energy in the form of food and the output of actual energy in the form of work. Some- times the fault lies in an unduly large income, sometimes in too small an expenditure; not unfrequently both factors co-operate. There would seem, however, to be another, but very limited, group of cases, in which, owing to some inherent lack of vital power in the cells of the body, fat is able to accumulate even in the absence of any excessive intake of food. This may explain some of the cases in which patients become fat even although they are very moderate eaters. There is reason to believe, however, that this is a very rare event, and that in the majority of cases in which it is alleged to occur, the patient is really the victim of self-deception. 1 It is obvious from these considerations that the proper treatment of obesity must consist either in a reduction in the total number of Calories of energy supplied in the food, or in an increase in the output of energy in the form of work, or in a combination of these methods. An increased expenditure can be achieved by the use of suitable muscular exercises, but that method of treatment does not concern us here, and we may now direct our attention to the best means of diminishing the intake of energy in the form of food. And first one may ask, Which chemical ingredient of the food is it most important 1 See Hirschfeld, ' Ueber den Nahrungsbedarf der Fettleibigen,' Berliner Klimk, April, 1899, Hft. 130, 1-22 ; also Hoffmann, Leyden's ' Handbuch der Ernahrungstherapie,' p. 540; Von Noorden, 'Die Fettsucht,' p. 24, Vienna, 1900; and Rubner, 'Beitrage zur Ernahrung im Knabenalter,' Berlin, 1902. The obesity of young subjects, however, seems sometimes to be due to ,1 con- genital peculiarity of metabolism, and not to any excessive consumption of food. Such cases do not lend themselves to dietetic treatment. DIET IN OBESITY 5°3 to reduce — the proteids, carbohydrates, or fats? Physiological in- vestigation has shown that all of these ingredients may serve as sources of fat in the body if consumed in excess, but the risk of proteids being converted into fat seems to be very small. As regards the relative dangers of an excess of carbohydrates or fats in the food, classical authorities on the subject are not altogether agreed, and, as we shall see immediately, schemes of diet for the obese have been drawn up, in some of which the carbohydrates have been specially restricted, while others are characterized by a limitation of fats. The progress of research into metabolism in obesity, however, has shown that the question is, after all, and as far as the mere storage of fat is concerned, one of indifference. The only essential point is to reduce the total number of Calories supplied in the form of food, and whether this should be accomplished by limiting the carbo- hydrates or the fats, or both, is purely a matter of convenience, and one which must be decided chiefly by the tastes and habits of each individual patient. 1 The next problem which presents itself, then, is, To what extent should the total number of Calories in the diet be reduced ? Here, again, no hard-and-fast rule can be laid down. In some cases, such as in the very young, in whom probably a marked congenital tendency to the disease exists, it is difficult to keep the undue forma- tion of fat in check at all. In others, such as the very old, it is probably unwise even to make the attempt, while in particular instances — for example, those in which the chief deposit of fat is in the abdomen — treatment is always peculiarly difficult. In an average case, however, such as is most commonly met with in the later periods of middle life, one must be guided mainly by the degree to which the obesity has developed, and in judging of this it is always better to go by the general appearance of the patient rather than by tables of height and weight. Following the teaching of Von Noorden, and assuming that an average man of this age requires to be supplied with from 2,500 to 3,000 Calories of energy daily to meet his current expenditure in heat and work, one may divide cases into three groups : 1. Those in which it is merely necessary to reduce the diet by one-fifth, which means the supply of 2,000 Calories. This can best be done by cutting out sugar by reducing the supply of fat and carbohydrates, and by restricting the consumption of alcohol. This plan is only likely to be successful if it can be combined with 1 See Von Noorden, op. cit. 504 FOOD AND DIETETICS a free use of muscular exercise, and in any case the loss of weight under it can only be very slow. 2. In severer cases the diet may be reduced two-fifths, which means supplying only 1,500 Calories. Here it will be necessary still further to reduce the amount of fat in the diet, and to limit the con- sumption of bread ; and in this case also the loss of weight is apt to be slow, unless the patient can at the same time take at least a moderate amount of active exercise. Von Noorden states that he prefers this scheme to any other, because, while it usually gives good results, it is never attended by any disagreeable consequences. He specially recommends it — (1) In patients who are being treated at home, and are continuing to follow their usual occupation. (2) In patients who can go into the country, and take a moderate amount of exercise without requiring medical supervision. (3) In those for whom, owing to the presence of visceral com- plications, a rapid ' cure ' might be dangerous. (4) As the habitual diet in advanced cases in which periods of greater restriction are being observed. 3. The third degree of diet is that in which the total Calories supplied are reduced three-fifths — i.e., to about 1,000 to 1,500 per day. This group includes all the classical ' systems ' of diet for obesity, as is shown by the following table : c vstem Proteid. Carbohydrate. Fat. - , . * ' Grammes. Grammes. Grammes. calories. Banting 172 81 8 1,100 Oertel (maximum) .. 170 120 45 1,600 ' ,, (minimum) .. 156 75 25 1,180 Ebstein .. .. .. 102 47 85 1,300 Hirschfeld (maximum) . 139 67 65 1,400 ,, (minimum) 100 50 41 1,000 Von Noorden .. .. 155 112 28 1,366 Some of these demand a word of description. Banting System. — This scheme of diet was first popularized by the writer whose name it bears, 1 although it had previously been recom- mended in France by Leon. Banting suffered from an extreme degree of obesity, so great, he tells us, as to render him unable to tie his own shoe, and to compel him to go downstairs backwards. Having consulted various physicians without success, and having tried the effects of violent 1 See "A Letter on Corpulence addressed to the Public,' by William Banting ; London, 1863. DIET IN OBESITY 5°5 rowing exercise and a course of Turkish baths, he was finally advised by an aural surgeon, Dr. Harvey, to abstain from bread milk, butter, sugar, and potatoes, ' which had hitherto been the main and, as he thought, innocent elements of his existence,' and to adopt instead the following diet : Breakfast. 4 to 5 ounces of beef, mutton, kidneys, broiled fish, bacon, or any cold meat except pork ; a large cup of plain tea, and a little biscuit or i ounce of toast. Dinner. 5 to 6 ounces of any lean meat or fish, any vegetable except potatoes, i ounce of dry toast, some fruit out of a pudding, any kind of poultry or game, and 2 to 3 glasses of good claret, sherry or madeira. Tea. 2 to 3 ounces of fruit, a rusk or two, and a cup of plain tea. Supper. 3 to 4 ounces of meat or fish as at dinner, and a glass or two of claret. For a ' night-cap ' he was allowed a tumbler of ' grog ' without sugar, or a glass or two of claret or sherry. On this regimen Banting lost 35 pounds of weight in thirty-eight weeks, which is not surprising, considering that his diet hitherto had consisted of bread-and-milk for breakfast, or a cup of tea with plenty of sugar and milk, and buttered toast ; meat, beer, much bread (of which he was always very fond), and pastry, for dinner ; a tea of the same composition as breakfast, and a fruit tart or bread- and-milk for supper. He found sugar the most fattening of all foods, 5 ounces of it in a week causing his weight to rise 1 pound ; and he calls milk, sugar, beer, and butter ' human beans,' because they have the same effect in the human subject that beans have in the case of the horse, and he regards these articles as ' the most insidious enemy an elderly man with a tendency to corpulency can possess, though eminently friendly to youth.' He adds : ' I can con- scientiously assert that I never lived so well as under the new plan of dietary.' It will be observed that the chief chemical characteristic of the Banting system is the great predominance of proteids in the diet, and it has been asserted, though with only a limited degree of truth, that owing to this fact one is more likely to insure a loss of body fat alone on it, and to prevent any inroads into the muscular tissues, than by any other plan. 1 1 For a discussion of this subject see Dapper, Zeit. f. Klin. Med., 1893 xxiii. 113, and Von Noorden, op. lit. 506 FOOD AND DIETETICS Be this as it may, the system has certainly the advantage of simplicity and of being easily regulated, and on this account it is likely to retain its popularity. It should be pointed out, however, that the large excretion of nitrogen which such a diet entails is apt to throw a severe strain upon the kidneys, and for that reason it is well always to investigate the state of these organs before embarking upon the treatment. The chief characteristic of Oertel's system, 1 which has been largely popularized in Germany, though with some slight modification, by Schweninger, is that he restricts the consumption of fat more than that of carbohydrates, and at the same time lays great stress on limiting the amount of fluid in the diet. To the discussion of the latter point we shall return later, but at present the following may be taken as a type of his system. It is adapted, of course, to German habits : First Breakfast. ij ounces of white bread, 2 eggs, a large teacupful of coffee with 1 ounce of milk and 1 lump of sugar, and (in some cases) £ ounce butter. Second Breakfast. 2 ounces of lean meat, § ounce of coarse bread, 3J ounces of light wine or clear soup. Dinner. Si ounces of roast beef with salad or green vegetables, 3j ounces of pudding and fruit, a tumblerful of light wine, and (in some cases) 1 ounce of bread. Afternoon. A small cup of coffee as at breakfast. Supper. J ounce of caviare, sj ounces of chicken or game, J ounce of cheese, § ounce of coarse bread, a tumblerful of water or light wine. Ebstein 2 modified Banting's diet by increasing the proportion of fat and giving less proteid, as follows : Breakfast. A large cup of tea without milk or sugar, 2 ounces of bread with plenty of butter. Dinner. Soup, 4! to 54 ounces of meat with fat sauce, green vegetables, fresh fruit, 2 to 3 glasses of light wine. Afternoon. Tea as at breakfast. Supper. Tea, one egg, fat roast meat or ham, smoked fish, about 1 ounce of bread with plenty of butter, a little cheese, and fresh fruit. 1 Oertel, ' Twentieth Century Practice,' ii. G25. 2 ' Corpulence, and its Treatment on Physiological Principles ' (translated from sixth German edition) ; Wiesbaden and London, 1884. DIET IN OBESITY 5°7 Ebstein gives the following summary of his plan : ' The permission to enjoy certain succulent things, always, of course, in moderation, as, for instance, salmon, pat6-de-foie-gras, and such-like delicacies, reconciles the corpulent gourmet to his other sacrifices. These consist in the exclusion of the carbohydrates. Sugars, sweets of all kinds, potatoes in every form, I unconditionally forbid. The quantity of bread is limited at most to 3 or 3J ounces a day, and of vegetables I allow asparagus, spinach, the various kinds of cabbage, and the legumes. Of meats I exclude none, and the fat in the flesh I do not wish to be avoided, but rather sought after. I permit bacon-fat, roast pork and mutton, and kidney-fat, and when no other fat is at hand I recommend marrow to be added to the soups. I allow the sauces as well as the vegetables to be made juicy, as did Hippocrates, only for his sesam-oil I substitute butter.' Hirschfeld's diet 1 resembles that of Ebstein very closely : Breakfast. 2 ounces of bread, and coffee without sugar or milk. Forenoon. 2 eggs. Dinner. Soup with 2 ounces of rice (weighed uncooked), 8 ounces of lean meat boiled or roasted with a little fat. Afternoon. Black coffee. Supper. 2 ounces of cream cheese, 4 ounces of bread, J ounce of butter. "Von Noorden 2 gives a large number of small meals, and restricts fats more than carbohydrates : 8 a.m. : 3 ounces of cold lean meat, 1 ounce of bread, a cup of tea or coffee with a spoonful of milk, but no sugar. 10 a.m. : 1 egg. Noon : A cup of strong soup without fat. 1 p.m. : A small plate of clear soup (a la Julienne or a la jardiniere), 5 ounces of lean meat or fish, 3J ounces of potatoes, green vegetables, 3J ounces of fresh fruit. 3 p.m. : A cup of black coffee. 4 p.m. : 7 ounces of fresh fruit. 6 p.m. : A glass of skimmed milk. 8 p.m. : 4J ounces of cold lean meat with pickles, 1 ounce of Graham bread, 2 to 3 spoonfuls of fruit cooked without sugar. He also allows two glasses of wine a day. It will be observed that all of these systems, seeing that they fal) 1 ' Beitrage zur Ernahrungslehre des Menschen,' Virchow's Archiv., 1888, cxiv 301 ; and ' Ueber den Nahrungsbedarf der Fettleibigen,' Berliner Klinih, Hft. 130, 1899. 2 Op. cit., p. 122. 5o8 FOOD AND DIETETICS short by at least 1,000 Calories of the number requisite to meet the outgoings of the body, must be regarded as starvation methods of treatment. 1 For this reason it is never safe to carry them on for more than a few weeks at a time, during which the patient must be under strict supervision, and any symptoms of weakness or heart failure carefully watched for. As regards the relative advantages of the different methods, a good deal of difference of opinion exists, and some patients will be found to prefer one plan, some another. Ebstein specially recommended the inclusion of a considerable amount of fat in the diet, on the ground that, while it does not tend to the production of fat more than its equivalent of carbohydrate, it has a greater ' satisfying ' power, and tends to allay feelings of hunger. It may be doubted, however, as Von Noorden has pointed out, whether this is really true of such quantities of fat as it is safe to allow, while, on the other hand, the greater bulk of carbohydrate food certainly tends to produce a feeling of satisfaction. The point, however, is really one of indifference. Some patients stand a limitation of fat better than that of carbohydrates, whereas in the case of others the reverse holds good, but as long as the total number of Calories in the diet is kept low fat must inevitably continue to be lost from the body. Whether or not it is advisable to restrict the amount of fluids in the diet, and if so to what extent, we shall proceed to discuss immediately. On the Use of Particular Articles of Food in Obesity. In drawing up a scheme of diet for the obese, it is well to avoid too great variety, for that always tends to increase appetite. For the same reason, all spices, condiments, and other articles that increase the desire for food, must be used very sparingly. The following list of the Calorie value of some of the commoner articles of food may be of assistance in enabling one to arrive at some idea of their relative suitability as articles of diet for the corpulent. (See also the tables on pp. 7, 426.) 1 This statement is hardly true for all individuals. The writer, for instance, has recently had a patient — a lady of 12 stones — who lost no weight on Ebstein's diet for five weeks, although the amount of energy yielded by her daily supply of food was less than 1,200 Calories. Later on she began to lose weight at the rate of a pound a week. DIET IN OBESITY 5°9 Article. Calories. 2 ounces of cheese.. 224 1 ounce of butter (enough to cover three or four slices of bread) . . 208 A helping of cooked lean meat (4 ounces) . . . . . . . . 196 A tumblerful of milk . . . . . . . . . . . . '. . 140 A moderately thick slice of bread (2 ounces) . . . . . . . . 138 ,, „ ,, and butter . . .. .. .. 208 A heaped dessert-spoonful of milk pudding .. .. .. ..no One egg . . . . . . . . . . . . . . . . . . 70 One medium-sized potato (2 ounces) . . . . . . . . . . 45 An ordinary lump of sugar . . . . 16 The use of sugar should be avoided altogether, and saccharin employed as a sweetener instead. Visible fat should be removed from meat, and the richer meats, such as pork, goose, etc., and the fatter fishes, such as mackerel, eel and salmon, interdicted. Milk and its products should only be used in moderation, and puddings must be unconditionally forbidden. Bread, also, is a very dangerous food, but as it can hardly be dispensed with altogether, it should only be allowed in weighed quantities. It is well, too, to select the coarsest sorts of bread, which contain much indigestible bran, such as Graham bread ; for a given bulk of these yields much less nutri- ment to the body than an equal weight of fine bread. Potatoes, as the table shows, are not nearly so dangerous as bread, and may often be allowed in moderation. It is better to avoid the other roots and tubers, but green vegetables and mushrooms may be freely permitted, and their great bulk has the advantage of producing a feeling of satisfaction. Dried fruits as containing much sugar must be strictly forbidden, but fresh fruit may be allowed in moderation, and, if stewed, should be sweetened with saccharin. All made dishes, thick soups, sauces and pastry must be cut out of the menu, as they are subtle vehicles for the conveyance of much fat and starch into the body. The arrangement of the meals must be regulated to a large extent by the habits of the patient. Where it is feasible, most authorities seem to prefer that they should be small and frequent, as the total amount of food consumed is thus more easily kept under control. Beverages in Obesity. The first question to be settled regarding the use of beverages in obesity is whether or not it is important to diminish the total amount of fluid in the diet in that disease. The restriction of fluids was first advocated by a French military surgeon — Dancel — in a book 5™ FOOD AND DIETETICS published in 1863. 1 He had observed the influence of water and watery fluids in producing abdominal development in the horse, and he made reduction of fluids one of the main principles in the regimen which he drew up for corpulency. The principle was subsequently adopted by Oertel and Von Schweninger, and attained through their advocacy a very considerable degree of popularity. Exact observation, 2 however, has now shown that the influence which the amount of water in the diet exerts upon the production or loss of fat in the body is very small in amount and uncertain in degree, and that, as a matter of fact, fat people are less affected by a restriction of fluids than are lean. Dancel restricted the intake of fluids to 7 to 14 ounces per day, Oertel allowed a daily maximum of i\ pints, and Von Schweninger of about 3 pints, but the latter made a strong point of fluids not being taken along with solids, but rather between meals. The opinion of most authorities at the present time 3 seems to be that the restriction of fluids has, at best, only an indirect influence. In the case of some patients the interdiction of fluids at meals inter- feres with appetite, and so results in less solid food being consumed. In such cases the method may be of value, but where no such result ensues, the loss of weight which results is only temporary, and due to a diminution of the body fluids. It is probable, too, as Yorke Davies has pointed out, 4 that one reason why restriction of fluids has given better results on the Continent than one sees in this country is, that in Germany, at least, restriction of fluids is very often synonymous with restriction of beer. The whole question, indeed, is to be regarded as one affecting the technique of feeding rather than the physiological principles upon which the dietetic treatment of obesity is founded. 6 Von Noorden concludes that restriction of fluids should only be insisted upon when the following indications are present : 1. Weakness of circulation. A dry diet is advisable here for the sake of the heart, apart altogether from the obesity. 2. At the commencement of many 'cures' Here the initial loss of weight which the restriction of fluids brings about is calculated to make a great mental impression on the patient. 3. In cases where the restriction results in a diminished appetite for fat- forming foods. 1 See also Bull, de Therap., 1864, lxvii. 44. 2 Dennig, Zeit. ]. Didt. und Physik. Therap., 1899, ii. 292. 3 See a discussion on obesity reported i?i the Verhandl. d. qten Cong. f. Inn. Med., 1885. * • Foods for the Fat,' p. 26. 6 See Von Noorden, op. til., p. 124 et seq. FATTENING DIET 5 11 4. Where sweat excretion is excessive. He considers that the total amount of fluid allowed should not be reduced below 2-J- pints per day. Where a Banting or any other very nitrogenous diet is being adopted, the restriction of fluids is to be avoided, as being opposed to the free elimination of the products of nitrogenous waste. Of the different sorts of beverages in common use, water and the saline mineral and table waters may be regarded as harmless ; but the sweetened effervescing waters, such as lemonade, should be avoided. Tea and coffee may be freely permitted, if taken with little milk and no sugar. Cocoa is often forbidden, but the amount of nutriment which an ordinary cupful of it contains is so small as to be hardly appreciable. In many people, also, it has the advantage of lessening the appetite for solid food. Alcoholic beverages should be avoided as far as possible, for alcohol is, as we have seen, a direct sparer of fat. If a small allow- ance is indicated on other grounds — e.g., feebleness of heart — a dry natural wine should be selected, or its alcoholic equivalent of well- matured spirit freely diluted with water. All strong and sweet wines, liqueurs and malt liquors should be interdicted. Fattening Diet. In the previous section we have dealt with the dietetic methods of reducing fat. We have now got to consider the means at our disposal for increasing it. Generally speaking, any excess of food which is supplied to the body beyond the amount required to meet the current outgoings of energy in the form of heat and work will be stored up in the form of fat. One does, however, meet with cases in which, owing probably to some failure of assimilative power, it is found to be very difficult to achieve the laying on of fat, even although a considerable surplus of food is supplied, but as a rule one may say that in order to fatten the body one has merely to insure the supply of an excess of food. It will be obvious that one important means of bringing about such a surplus of income over expenditure is to diminish the out- goings of energy from the body. For this reason, rest, more or less complete, is always an important aid in cases in which one wishes to fatten. As regards the constituents of the food which are most important in respect of fattening properties, it may be said that fat itself, owing to the ease with which it can be stored, takes the first place. It has 5" FOOD AKD DIETETICS been calculated by Rubner that ioo parts of fat, 248 of carbohydrate, and 313 of proteid, are equivalent in fat- forming power. Whether all forms of fat are equally valuable in this respect must be left undecided, but it is probable that some fats produce a more stable kind of adipose tissue than others. 1 When one comes to the actual construction of a fattening dietary, however, due attention must be paid to the powers of the digestive organs, and for that reason it is better to see that carbohydrates and fats are both abundantly represented, rather than to trust to one or other of them alone. Munk is of opinion that, in order to insure the laying-on of fat, one should supply 90 to 100 grammes of fat, 100 to no of proteid, and about 500 of carbohydrate, daily. The permanent enrichment of the body in proteid (practically in muscular tissue and blood) is very much more difficult of accomplish- ment than the mere deposition of a certain amount of fat. So great is the tendency for nitrogenous equilibrium to assert itself that it is almost impossible to bring about a storage of proteid in the body 1 unless (1) a considerable amount of muscular exercise is taken at the same time, or unless (2) there has been a previous wasting of the muscles, such as occurs during acute disease. In the former case the bulk of the muscles exercised can, up to a certain limit, be increased ; in the latter the normal muscular develop- ment can be again attained. The one process occurs during train- ing, the other during convalescence. In both proteid is stored up. In practice the storage of proteid can be accomplished, granted the presence of one or other of the above conditions, either by increasing the actual amount of proteid in the diet or by raising the proportion of proteid-sparers. Weight for weight carbohydrate is, it will be remembered, a more powerful proteid-sparer than fat; but here, again, in actually constructing the dietary it is better to avail one's self of both ingredients. 2 Practically, then, it comes to this, that where one wishes to lay on fat only, one should increase the proportion of fat and carbohydrate > See Weir Mitchell, ' Fat and Blood, ' p. 25. 2 For a discussion of this subject see Rosenfeld, ' Die Bedingungen der Fleischmast,' Berliner Klinih, 1899, Hft. 127, 1-28. In a more recent paper by Kauffmann (' Der Gegenwartige Stand der Lehre von der Eiweissmast,' Zeit f. Diat. und Physik. Therapie, 1903, vii. 355), the whole question is carefully reviewed, and the conclusion arrived at that some proteid probably can be laid up in the body, and that this may be accomplished either by an increase of the proteid in the food or by supplying a larger amount of proteid-sparers. The former method is preferable, if one does not wish to increase the fat in the body at the same time. * See Wicke and Weiske, Zeit. f. Physiolog. Ckem., 1895, xxi. 42, and 1896, xxii. 137. DIET IN CONVALESCENCE 5 l 3 in the food, laying, perhaps, greater stress on the former ; but where one wishes to lay on proteid, the proportion of that ingredient in the food should be increased as well, and prominence given to the increase of carbohydrate rather than to that of fat. A fattening diet is wanted in three chief sets of conditions : (i) In convalescence from acute illness ; (2) in wasting diseases, such as tuberculosis ; (3) in some nervous disorders, of which neurasthenia may be regarded as the type. In convalescence the waste of proteid and fat which the preceding illness has entailed must be made good. Out of respect, however, to the debilitated digestive powers of such a patient, one must proceed with caution. There is reason also to believe that the metabolic conditions of fever continue for a day or two after the temperature has fallen, and on that account some observers advocate the continuance of the fever diet for three days after the pyrexia has ceased. One can then begin to thicken the patient's beef-tea, soups, and milk with cereal flours, and to add other farinaceous foods to the diet. Many of the patent malted foods may be usefully employed here. The increase of proteid may be accomplished by the addition of pounded meat to soups in the form of purees, and one may gradually pass on to the administration of the more easily digested forms of animal food, such as chicken, fish, and eggs. Jellies are also agreeable to the convalescent, and, along with custard or light milk puddings, are pleasant forms of proteid- sparing food. The enrichment of the diet in fat may be conveniently deferred till later, and should be accomplished by the free use of cream, butter, bacon and suet, or, if these cannot be compassed in sufficient quantity, one may have recourse to cod-liver-oil (see also p. 568). One of the simplest methods of enriching the diet in wasting diseases is by adding to it a certain quantity of milk. There is frequent opportunity in cases of phthisis of observing the good effects of adding 2 or 3 pints of milk to the ordinary diet, 3 pints represent- ing an addition of about 1,000 Calories to the value of the diet. It can be taken both as a beverage with the usual food and also between meals. Fat seems to be of special value in the diet of tuberculosis, and by the use of the more easily digested forms of it, such as butter, bacon, pork, salad-oil and cream, one has usually not much difficulty in persuading patients to take enough of it, even when, as is not unfrequently the case in phthisis, a considerable natural repugnance 33 5H FOOD AND DIETETICS to fat exists. Smith x recommended that phthisical patients should take the following amount of fat daily : As milk . . . . . . . . . . 2^ ounces. ,, butter . . . . . . .. . . 2 ,, ,, bacon . . . . .. . . . . 2-4 ,, In meat . . .. .. .. . . i£ ,, As salad-oil . . . . . . . . 1 ounce. ,, suet in puddings .. .. •• I ,, Cream ad lib. Recently, however, there has been manifest a reaction amongst those best qualified to judge against the indiscriminate stuffing of tuberculous patients with fatty and carbohydrate foods, and a recognition of the value and importance of an increased supply of proteid, or, in practice, of a diet containing plenty of meat. 2 Such a diet seems to increase the richness and bactericidal power of the blood ; it stimulates leucocytosis, and helps to replace the waste of muscular tissue which is such a marked feature in phthisis. Bards- well and Chapman, who have made a special study of the dietetics of phthisis, recommend for a phthisical male patient who is not doing any work a diet containing about 150 grammes of proteid, 150 grammes of fat, and 250 grammes of carbohydrate, with a Calorie value of 3,000. For women the standard should be somewhat lower, viz., proteid 126 grammes, fat 150 grammes, carbohydrate 220 grammes, with a Calorie value of 2,814. The following actual diets conform to these standards : Article of Food as Served. Milk Bread . , Porridge Butter Breakfast meat, such as bacon, fib, etc. Ordinary meat Pudding Vegetables Amount Prescribed. 1500 CC. 180 grammes. 120 ,, 45 30 180 300 qs. For Women. 1500 CC. 135 grammes. 120 ,, 45 3° 150 180 qs. 1 Lancet, 1864, i. 432. 2 See Forbes Ross, ' Meat Albumin Dietary in the Treatment of Tuberculosis,' Brit. Med. Jottrn., 1901, ii. 1061 ; Bardswell, Goodbody, and Chapman, 'On the Effects of Forced Feeding in Cases of Pulmonary Tuberculosis,' etc., ibid. , 1902, i. 449 ; ' Dietetics in Tuberculosis,' Proceedings of the Royal Society, B., lxxx. 151 ; Galbraith, ' The Dietetic Treatment of Pulmonary Tuberculosis from the Point of View of its Hematology and Histopathology,' ibid., March 14, 1903 ■; and Lloyd Smith, ' Diet in Phthisis,' Lancet, 1903, ii. 1015. DIET IN TUBERCULOSIS 515 The exact amount and constitution of the diet in each case should be fixed after due consideration has been given to the activity and extent of the disease, the amount to which the patient's weight is below his normal, his digestive capacity, and, to some extent, his personal dietetic likes and dislikes, but one should aim at making good lost weight at the rate of 1 to 2 pounds per week. When the patient has once regained his normal weight or a little more, the diet should be reconstructed more upon the lines of what would be suitable for the same person in perfect health, and if active exercise or muscular work is being performed, the amount of fat and carbo- hydrate in the diet should be increased. Anorexia in phthisis is to be met by a change in hygienic surround- ings, by the use of bitters, by frequently varying the menu, by giving the food in a more fluid form; and by eliminating the more bulky and less nutritive articles — e.g., porridge, green vegetables, etc. The necessary proteid in such circumstances can be got in by fortifying fluid foods with one of the soluble casein preparations or by adding it to puddings ; fat can be taken in the form of cream and sugar as grape sugar, lactose, lemonade, etc. When fever exists, the food should be given as far as possible in apyrexial intervals or after the temperature has been artificially reduced by sponging. If the digestive power is good, an effort should be made to maintain the standard diet in spite of the fever, but if this proves impossible, the diet must be constructed on the same lines as for anorexia. The method of feeding up neurasthenic patients has become widely known under the title of the Weir-Mitchell Treatment or Rest Cure. The general management of such cases cannot be fully described here, but some points connected with the diet which form so important a part of the plan must be mentioned. - It is usual to begin with milk alone, given quite fresh and perfectly skimmed. The milk should be sipped slowly, it should be warm, and from 40 to 80 ounces should be given daily in equal quantities every two hours. Various methods of varying the flavour of the milk are described on p. 131. After two or three days, some of the milk may be thickened with farinaceous foods (arrowroot, cornflour, groats, one of the numerous patent preparations, etc.), and as digestive power improves, lightly cooked eggs, underdone meat, fish, chicken, game, sieved potato, and bread-and-butter may be gradually added until the patient is taking three large meals a day with from 3 to 5 pints of milk and perhaps a gill of cream and an 33—2 516 FOOD AND DIETETICS ounce of malt extract in addition. The total fuel value of such a diet may in some cases exceed 10,000 Calories. The food should be plain, appetizing, and well cooked, the chief meal being in the middle of the day, while the evening one is lighter. Part of the milk may be taken with the meals, the rest between them. In all cases in which a large amount of food is being administered, the use of alcohol, in some form or another, will often be found a great help. Especially is this the case when the diet is very rich in fat. The safest guide to its use is the state of the appetite and digestion. Where these are improved by its administration, it does good. The form to be selected is largely a matter of taste, but a sound red wine, such as burgundy, is perhaps most generally useful, or, if a malt liquor be preferred, good bottled stout. The Dietetics of Gout. Unfortunately, chemical pathology is not yet in a position to furnish us with very clear indications as to the best diet for the gouty. In spite of all the work which has been done upon the subject, we are still, it must be confessed, very much in the dark as to the relations of uric acid to general metabolism and to the gouty state. It is becoming more and more clear, however, that, in mammals at least, uric acid is derived mainly, if not entirely, from the decomposition of nucleins either contained as such in the food, or produced by the disintegration of the body cells. Uric acid from the first of these sources may be conveniently described as ' exogenous uric acid,' while the fraction produced in the body may be designated as ' endogenous.' While the nucleins of the food are the main, they are not the exclusive, source of the exogenous uric acid. Part of it is also derived from such substances as caffeine and from free ' purins ' contained in the food. Further, the whole of the uric acid derived from the food does not appear in the urine as such. Part of it is converted in the body into urea and other compounds. The fraction so changed varies from one-quarter to one-half of the total possible yield, but the amount is very constant for different foods, and appears to vary but little in different individuals. The chief fluctuations in the amount of uric acid in the urine can be explained by variations in the amount of uric-acid-yielders (purins) contained in the food ; the endogenous fraction, on the other hand, seems to be remarkably fixed, but as to its exact seat and mode of formation, and the conditions which control it, we have still much to learn. blET IN GOUT ffl "Those who believe that uric acid is the fons et origo of the gouty state have therefore concentrated their attention upon limiting the intake of uric acid formers in the food, and recommend the adoption of a ' purin-free ' diet. Such a diet is described in detail elsewhere (p. 551), but the writer would only say here that, although it un- doubtedly gives good results in some gouty persons, it is by no means suited to all, as its prolonged use is apt to lead to impairment of the general health, and particularly of the digestive capacity. Nothing is more certain, moreover, than that a patient may still suffer from gout, even although the substances capable of yielding uric acid are reduced in the diet to a minimum. For we have still the endogenous production of uric acid to deal with, and about the influence of diet on such production we know almost nothing. Nor does accu- mulated clinical experience afford as much help as one might expect, for the opinions of different writers on the subject, as so often happens, are exceedingly conflicting, and a system which suits one patient does not necessarily agree with another. On the whole, the belief seems to be gaining ground that quantity must be attended to quite as much as quality, and that the best diet for the gouty is a spare one, com- posed of simple ingredients, containing only a moderate amount of carbohydrate and fat, and in which not too much of the proteid is derived from animal sources. In the light of the above facts, it might be well to add that, so far as is compatible with healthy nutrition, the animal ingredients should consist mainly of milk and eggs ; certainly meat should not be taken oftener than once a day. The dietary usually prescribed for gouty patients at Carlsbad is based upon these principles, and is as follows 1 : Breakfast : weak tea with cream, biscuits (2 to 4 ounces), butter (£ ounce), two soft- boiled eggs. Dinner : soup, either clear or with pearl barley or rice (1 ounce) ; fish — trout, pike, or perch (3^ ounces) — with melted 'butter, lemon-juice, and potatoes (2 ounces) ; roast veal (3^ ounces) or mutton cutlets or roast fowl, spinach, cheese (1 ounce), stewed fruit (3^ ounces), bread (5 ounces). Supper: soup or milk or weak tea with milk, biscuits, lean bacon, or one or two eggs, jam. Beverage at dinner and supper: water, mineral water, \ pint of light claret with water or two tablespoonfuls of whisky with a half-bottle of mineral water. It is important to remember, however, that there is no routine plan which is suitable in all cases. The state of the patient's nutrition and digestive and excretory organs may necessitate modifications of the diet in various directions, as may also the presence of complications. ' "The Treatment of Gout in Carlsbad,' by Dr. B. London {Practitioner, 1903, lxxi. 161, 320). 518 FOOD AND DIETETICS Beverages in Gout. What he drinks is, to the gouty man, quite as important as what he eats. Tea, coffee and cocoa are certainly sources of uric acid, and may therefore require to be avoided. Experience also shows that the free consumption of alcohol is harmful, and, if possible, the patient should try to live without it. Too often, however, this is a counsel of perfection, and in that case a sound natural wine, which may be taken with some alkaline mineral water, is the best beverage to select. The stronger wines are dangerous, both on account of the large proportion of alcohol which they possess, and also because they are apt to contain sugar, which is prone to excite dyspepsia in the gouty, even if it has — a point which is still sub judice — no influence on the production of uric acid itself. Champagne is also injurious, and so, too, is bottled cider, though ' rough ' cider and dry sherry usually agree well. It is the fashion to recommend whisky to gouty people, and to this course there can be no objection, provided it be taken well diluted, and the quantity limited to 2 ounces a day. It is certainly a useful resource in cases in which the natural wines disagree. On the whole, however, it must be admitted that there is no better beverage for gouty people than plain water, and they should be encouraged to drink largely of it, as an admirable aid to the elimination of nitrogenous waste. Plan of Diet in Gout. In view of the principles discussed above, the general directions for the diet in a case of chronic gout may be summed up as follows : GENERAL RULES. Meals should be as simple as possible. Butcher's meat should only be eaten once a day, and in a very moderate amount. Sugar and sweets should be taken sparingly. Bread should be taken in the form of crisp toast or rusks. Raw fruit should never be taken at a meat meal, and is best consumed early in the day. If alcohol is necessary, it should be taken only in the form of brandy, whisky, or a light still Moselle. Articles to be Avoided. 1. Rich meat-soups : Oxtail, turtle, mock turtle, kidney, mulligatawny, hare, giblet. 2. Salmon, mackerel, eels, lobster, crab, mussel, salted fish, preserved fish, smoked fish, tinned fish. 3. Duck, goose, pigeon, high game. DIET IN GOUT 519 4. Meats cooked a second time. Hare, venison, pork, lean ham, sweetbreads, liver, kidney, salted corned or cured meats, pickled meats, preserved and potted meats, sausages ; all articles of food pickled in vinegar ; all highly seasoned dishes and rich sauces. 5. Tomatoes, beetroot, cucumber, asparagus, rhubarb, onions, mushrooms, truffles. 6. Peas, beans, lentils and oatmeal. 7. Rich pastry, rich sweets, new bread, cakes, nuts, dried fruits, ices, ice cream. Scheme of Diet. Half a pint of hot water (flavoured, if desired, with a slice of lemon peel) should be slowly sipped immediately on rising, and again just before retiring to bed. Brealtfast. A selection may be made from the following articles : Whiting, sole or plaice, fat bacon, lightly cooked eggs, dry toast thinly buttered, tea infused for three minutes and then strained from the leaves. Luncheon and Dinner. Any clear soup. White fish (except those forbidden above), chicken, pheasant, turkey or game (not high). Butcher's meat (in accordance with the limitations already indicated). One of the following vegetables : Spinach, Brussels sprouts, French beans, winter cabbage, savoy cabbage, turnip tops, turnips, celery, potatoes in moderate quantity (but not new potatoes). Stewed fresh fruit. Salads of green vegetables are permissible, but only with simple dressings. Savouries are usually best avoided, but a morsel of cheese may be taken if free from mould. Rheumatoid Arthritis. There is no necessity for any restrictions of diet in rheumatoid arthritis ; on the contrary, an abundant and nourishing mixed diet is a most important part of the treatment, and the use of alcoholic beverages in moderation is permissible and sometimes advantageous. The old term ' rheumatic gout ' has been responsible for much harm done to these patients, for it has often led to their being put on a restricted diet under the belief that their disease was in some way related to gout, and required the same sort of diet. Gravel. The rational indications in the treatment of gravel would appear to be two in number : (1) To diminish the amount of uric acid which the urine contains ; (2) to increase its solubility. The former of these indications can be fulfilled, as far as the exogenous fraction of the urinary acid is concerned, by a diminution of the amount of uric-acid-yielders in the diet. We have already seen what are the best foods to select for that purpose. As regards 520 FOOD AND DIETETICS diminishing that part of the uric acid which is formed in the body itself, we are just as much at a loss as in the case of gout. Some authorities pin their faith to a diminution of the proteid-sparers — i.e., carbohydrates and fat — in the food. It is possible that this may favour the conversion of uric acid into urea, though it must be admitted that such a view is as yet very far from being proved. At all events, this plan has commended itself to such an experienced observer as Sir Henry Thompson. He recommends 1 that the diet should consist of white fish, poultry, game, lean meat, unsweetened jellies, bread, cereals, pulses, green vegetables and apples, but no sweet fruits. A little butter may be taken, and milk in moderation. The things to avoid are cream, eggs, cheese, pastry, pork and other fat meats, the fatter kinds of fish, suet, much milk or butter, and all substances containing sugar. He advises that farinaceous foods should be mixed with light broths instead of milk, and flavoured with some condiment, such as a pinch of curry or a morsel of chutney, instead of sugar. On the other hand, Goodhart, 2 after mentioning the case of a patient who suffered from gravel when on a milk diet, but got quit of it on changing to meat and port wine, says : ' I have come to be certain that in the majority of cases of uric acidity it is not a question of diet at all !' The second indication mentioned above — that of increasing the solubility of uric acid in the urine — can be accomplished by rendering the urine less acid. As Sir William Roberts has said, 3 the deposition of uric acid from an alkaline urine is a chemical impossibility. Now, we can certainly render the urine less acid by the free use of green vegetables and other foods containing alkaline salts of potash, but the same object can be accomplished so much more certainly and simply by the aid of drugs that the dietetic means at our disposal are hardly worth considering. The other factors concerned in keeping uric acid in solution are the presence of urea and mineral salts. An increase in these hinders the separation out of uric acid. For that reason it may be well that the diet should not be too poor in proteids, and that it should contain an abundance of common salt. As regards the question of beverages in gravel, the same remarks apply as in the case of gout. 1 ' Diseases of the Urinary Organs,' 8th edit., lecture xxv. 2 An address on ' Acidity,' Lancet, 1900, i. 1. 8 Croonian Lectures, 1892. TREATMENT OF SCURVY 521 OXALURIA. 1 In cases in which much oxalate of lime is separating out in the urine, one should select a diet which contains little oxalic acid and lime and plenty of magnesia, for the latter favours the solution of calcium oxalate. In order to meet the former indication, foods rich in oxalic acid should be avoided (e.g., spinach, rhubarb, tea, etc. See table on p. 297), and also those which contain much calcium (e.g., milk, egg, fresh vegetables. See p. 290), whilst the latter indication is met by the use of such foods as meat, cereals, bread, rice, peas, potatoes, apples, coffee, and beer. -Dietetic Treatment of Scurvy. Whatever view may be held as to the exact causation of scurvy, all experience goes to show that the introduction into the diet of a sufficient quantity of fresh vegetable foo.' has a powerfully curative effect in this disease. It would further appear that there is no particular form of vegetable food which is possessed of any specific influence over the complaint, but that all are about equally efficacious. The antiscorbutic power of fresh limes and lemons has been known since the seventeenth century, and these fruits still constitute the favourite remedy for the disease. It is important, however, that they should be fresh. Lime-juice which has been stored for a long time is apt to decompose into citric acid and carbonates, and thereby loses much of its value. An objection to lime-juice is its acrid taste, by reason of which it is sometimes found to be difficult to induce those who are exposed to the disease to take the juice regularly as a preventive. Lemonade made from fresh lemons is not open to this objection. Preserved vegetables, though of undoubted utility, appear to have a feebler antiscorbutic power than fresh. Sauer- kraut is the most serviceable of preserved vegetables, and Captain Cook employed it with success in some of his voyages. Infusion of malt is another powerful antiscorbutic. Forster, 2 who accompanied Cook in his second voyage, describes a severe outbreak of scurvy and its cure by infusion of malt without any other change in the diet. He adds : ' The encomiums on the efficacy of malt cannot be exaggerated.' Somd of the worst cases he saw took as much as 5 pints of the infusion per day. Here, again, it is important that the malt should be fresh, for its properties are impaired if it is allowed to become damp and mouldy. 1 See Klemperer and Tritschler, Zeit. f. Klin. Med., igo2, xliv. 337. a ' Notes from a Voyage Round the World,' by George Forster, vol. i„ 1777. 522 FOOD AND DIETETICS Fresh meat juice is of undoubted value as a remedy for scurvy, owing, in all probability, to the lactates which it contains. Milk is also serviceable, 3 pints of it containing as much citric acid as 1 ounce of lemon-juice, and instances are on record in which an outbreak of scurvy has been checked by the use of milk alone. Of beverages, French and Italian wines are admitted to possess antiscorbutic properties ; but opinions regarding the value of cider in this respect vary considerably. Dietetic Treatment of Infantile Scurvy. The treatment of infantile scurvy is purely dietetic. The use of tinned foods and boiled or sterilized milk must at once be stopped, and the child put upon a due allowance of fresh milk. Fruit juice should be added to the diet, a few teaspoonfuls of grape or orange juice, sweetened, if necessary, with a little sugar, being given every day. Fresh raw-meat juice is also of value, and may be given in quantities of \ ounce daily. Baked potato, too, owing to its rich- ness in potash salts, is of great service. It may be rubbed up with the milk into a thin cream and given through the bottle. Dietetic Treatment of Rickets. Whatever the exact pathology of rickets may be, there can be no doubt that one of the main factors in its production is an unsuitable diet. The diet may be either altogether deficient in nutritive properties or, more commonly, it is merely an ill-balanced one, in which the carbohydrate constituents are in relative excess when compared with the proteids and fats. The first step in treatment, therefore, is, in most cases, to decrease the starchy and sugary com- ponents of the food, and to increase the proteids and fats. With this object in view the use of all purely starchy foods — e.g., sago, tapioca, and arrowroot, should be discontinued, and the same is true of patent and proprietary infant foods, most of which contain an excess of carbohydrates. On the other hand, the amount of pure cow's milk in the diet usually needs to be increased, and fats should be given liberally in the form of cream, bacon fat, and butter. The use of condensed milk must be rigidly prohibited, as it is not only poor in fat, but, in most cases, contains a considerable excess of sugar. The nitrogenous constituents may be further supplemented by the use of raw beef -juice, scraped meat, or strong beef-tea. Yolk of egg is also a valuable food for rickety children, containing, DIET IN DISORDERS OF THE STOMACH 5^3 as it does, not only proteid and fat, but valuable organic compounds of phosphorus and iron, both of which elements the rickety patient needs. It may be given either in the raw state mixed with milk or very lightly boiled, and is usually well borne, even before the child is a year old. Oat flour and whole wheat flour may be used in moderate quantities to thicken some of the milk, the former being, perhaps, specially useful in virtue of the fat, iron and phosphorus in which it is so rich. 3. Diet in Disorders of the Stomach. General Considerations. Seeing that the essential role of the stomach is a mechanical rather than a truly digestive one, the physical form of the food must always be of more importance in dyspepsia than its chemical composition. In proof of this, one finds that so long as the stomach is able to pass the food on into the intestine absorption and nutrition go on without impairment, even although the digestive juices of the stomach itself are no longer present. 1 The first rule to be observed, therefore, in drawing up a dietary for disorders of the stomach, is to see that the food is presented in such a form that the stomach has but little difficulty in driving it on into the duodenum. In practice this means that the food must be in a fine state of division, and should be care- fully chewed. The question of bulk must also be considered. The larger the mass of" the food, the greater is the muscular labour imposed on the stomach. It is probably on this account that animal foods are, as a class, less troublesome to most dyspeptics than vegetable products. For the same reason, the meals in dyspepsia should be of small size, but taken at rather short intervals. As regards the behaviour of the dyspeptic stomach to the different chemical ingredients of the food, great individual differences exist, and in no class of case is it more important to study the question of idiosyncrasy. In a majority of instances, however, one finds that fat is more apt to give offence than any other constituent. This is particularly true of cooked fat, probably because in process of cook- ing fatty acids, acrolein, and other irritating substances, are apt to be liberated. On the other hand, butter and bacon-fat can usually be managed with but little difficulty. 1 See Von Noorden, ' Ueber den Stoffwechsel der Magen Kranken nnd Seine Anspriiche an die Therapie,' Berliner Klinik, 1893, Hft. 55, 1-19, and the same author, Zeit. f. Klin. Med., 1890, xvii. 137; also Moritz, Munch. Med. Woch., 1893, xl. 75. 524 FOOD AND DIETETICS We may now pass to the more detailed consideration of the dietetic treatment suitable in different forms of gastric disorder, leaving the discussion of some further general principles until we come to speak of ' functional ' dyspepsias. In handling the subject it will be well to take up first those diseases of the stomach which are accompanied by definite organic change, and afterwards to consider the so-called ' functional ' disorders in one group. Such an arrangement is admittedly unscientific, but it has the advantage of practical con- venience, and our knowledge does not at present admit of any more satisfactory system of classification. Gastric Ulcer. Ever since Cruveilhier clearly enunciated it, the principle has been accepted by all writers that rest for the organ is the point chiefly to be aimed at in arranging a diet for cases of gastric ulcer, and rest may be taken to mean the protection of the mucous membrane from both mechanical and chemical irritants. In very severe cases, and especially if there has 'been recent bleeding, rest must be absolute; This is accomplished by cutting off all nourishment by the mouth, and feeding the patient exclusively per rectum. Many cases have been treated in this way for periods of even twenty days at a time, 1 but it is rarely necessary to continue the injections for more than three days. The details of such treat- ment will be considered in the last chapter. After the period of rectal feeding, if all pain and vomiting have ceased, and in less severe cases from the outset, one can begin to feel one's way in giving food by the mouth. At first the diet must be strictly fluid, consisting of milk, diluted with lime or barley-water, or peptonized, given in quantities of about 5 ounces every hour, and at the body temperature. Small feeds of beef-tea may be given occasionally as a change. After another week, if all is going well, one may advance to semi- fluid diet, the milk and beef-tea being thickened with a little corn- flour, arrowroot, fine oat flour, or biscuit powder. Some of the patent predigested cereal foods are useful at this stage, and lightly cooked eggs are also permissible. The Leube-Rosenthal Meat Solution is also well borne as a rule, or one may substitute for it well-made ' whole beef-tea,' or a little of one of the patent proteid 1 See ' Traitement de certaines Maladies de l'Estomac par la Cure de Repos absolu et prolong^ avec Alimentation rectale exclusive,' Dr. A. P. Gros. Paris: Bailliere et Fils, 1898. GASTRIC ULCER 525 foods (Plasmon, etc.) may be given stirred into clear broth or in com- bination with arrowroot. Peptonized milk gruel is also very helpful at this period. After the lapse of another week one may add a little stale bread and butter, sweetbread or white fish, potato puree and custard, and gradually advance to underdone mutton, milk pudding, spinach and cauliflower, and from this to ordinary plain unirritating food (see Chronic Gastritis). Any recrudescence of symptoms must be the signal for immediately retracing one's steps and reducing the diet, and even when con- valescence is fairly established the patient must be careful for a long time to avoid all irritating and indigestible forms of food, and very hot or very cold articles. The above may be described as the classical method of dieting cases of gastric ulcer, although some of the details have varied in the hands of different physicians. In recent times, however, Lenhartz has introduced a very different plan of diet which now goes by his name, and has been widely adopted. The guiding principles of the Lenhartz diet are these : (1) To promote healing of the ulcer by giving as much nourishing food as possible ; (2) to ' fix ' the acid of the gastric juice, and so prevent its interfering with healing by ensuring that the food contains a large proportion of proteid ; (3) to prevent distension of the stomach by the use of small feeds. The method is carried out as follows i 1 The patient is kept absolutely in bed for four weeks, for the first two of which she is not allowed to move from the supine position for any reason what- ever. All mental excitement must be avoided. An icebag is kept upon the stomach almost continually for the first two weeks. The dietary consists of eggs beaten up with sugar, or in some cases with wine, and iced ; and of milk. These two foods are taken in small quantities at frequent intervals from a teaspoon, the quantity pre- scribed being spread over the day, and not given at definite meal- times. The first day 7 to 10 ounces of milk are given and one egg. The quantity is increased daily by 3^ ounces of milk and one egg until if pints of milk and six eggs, or in some cases eight eggs, are reached. From about the third to the eighth day raw or almost raw mince is added, starting with an ounce in divided doses, either beaten up with the egg or alone ; the next day, if the mince is well borne, •2 ounces are given ; minced beef may be used. 1 Spriggs, Brit. Med. Joum., 1909, i. 825. ?26 FOOD AND DIETETICS Food is given at first at hourly intervals from 7 a.m. to 9 p.m., but complete rest is allowed at night. Both the eggs and milk are iced and the eggs beaten up whole. Granulated sugar is added to the eggs on the third day. Some soluble casein preparation (Plasmon, Casumen, Sanatogen, etc.) may be used instead of the raw mince. From the seventh to the eighth day boiled rice is added, followed by softened bread, and later by a small quantity of bread and butter. One or more eggs may now be lightly boiled. The diet is then gradually increased by the addition of mince or pounded fish, with a corresponding reduction of eggs, until by the end of the fourth week the patient is on an ordinary mixed diet containing the common foodstuffs, with the exception of indigestible solids, such as peas or other seeds. The patient is instructed to masticate very slowly. On the twenty-eighth day the patient is allowed to get up, and dis- charged from the sixth to the tenth week. Lenhartz 1 claims that under this treatment (supplemented by the administration of iron and bismuth) pain disappears early, vomiting quickly subsides, and relapses are rare. The diet is also easier to carry out than the old ' starvation ' plan, besides being more agreeable to the patient. Acute and Chronic Gastritis. The dietetic treatment of acute gastritis must proceed on the same lines as that of gastric ulcer. The affection, however, being usually of but short duration, rectal feeding is rarely required, all that is necessary being to withhold all food until vomiting has ceased, thirst being meanwhile relieved by sips of hot water or by sucking frag- ments of ice. If there is great depression, a little champagne may be given, preferably diluted with seltzer-water. After the acute symptoms have subsided, the patient may gradually return to ordinary diet by the same stages as in gastric ulcer, but the steps of advance may usually be separated by periods of one or two days only, instead of by a week. In the treatment of chronic gastritis, it is important to avoid the use of anything that may irritate the gastric mucous membrane or excite a secretion of mucus. Mustard, pepper, spices, and con- diments of all sorts must be forbidden. Alcohol also should be avoided, especially in concentrated forms, for many of these cases are really brought on and maintained by the drinking of neat spirits. 1 Med. Klin., No. 14, 1907. See also Langdon Brown (Clin. Journ., 1908, xxxiii. 109). ACUTE AND CHRONIC GASTRITIS 527 Coffee is apt to be injurious owing to the oily substances which it contains, but weak tea may usually be permitted. Sugar is a very unsuitable food is these cases, more especially cane-sugar (see p. 277), for it excites a large secretion of mucus. Grape and milk sugar are much less likely to do harm. All cooked fats, pastry, sauces, and fat meats should be excluded from the dietary ; but butter is usually well borne if taken in moderation, and some patients can even digest bacon. Bread should only be taken thoroughly toasted, and potatoes in the form of puree. Cauliflower and spinach are the most suitable of vegetables. The food should be finely divided, eaten slowly, and but little taken at one meal. At the same time it is important to avoid mere ' slops.' The following may be regarded as a typical diet schedule for an average case : Breakfast. Lightly-cooked eggs, white fish (boiled), a little crisp bacon (not too fat), fowl, game ; dry toast with a little butter ; a small cup of weak tea with milk, but no sugar. Luncheon. Lean mutton, underdone, or underdone roast beef, white fish, etc., as at break- fast ; mashed potato and a little spinach or cauliflower ; dry toast ; custard pudding or unsweetened jelly ; a glass of alkaline mineral water, with perhaps a little claret or hock. * Tea. A small cup of tea, as at breakfast ; a slice of crisp toast and butter, or a plain biscuit or rusk. Dinner. A very little clear soup free from fat ; white fish, without sauce ; meat as at luncheon or breakfast, or a little sweetbread or tripe ; vegetables as at lunch ; custard, jelly, or fruit stewed without sugar, and free from skins or stones, or a little plain milk pudding ; a lith or two of orange at dessert, the juice only being swallowed and no sugar taken ; dry toast ; a glass or two of good claret or burgundy and some mineral water ; no coffee. It may be well to point out that many cases of alcoholic gastritis stand midway, as regards the urgency of their symptoms, between the acute and chronic forms of the disease, and in such cases confinement to bed on astiict milk diet is often the most successful method of treatment. Dilatation of the Stomach. 1. Obstructive. The kind of diet suitable for cases of dilated stomach must obviously depend upon the degree of pyloric obstruction. In all S28 FOOD AND DIETETICS cases, however, certain general principles must be observed : (i) It is important to avoid overburdening the weakened organ with any considerable mass of food at one time. The meals, therefore, should be small. (2) Substances must be excluded from the diet which are capable of supplying pabulum to the yeasts and sarcina? so often found in the dilated viscus. The food should, therefore, be unfer- mentable. (3) Attention should be concentrated on rendering the food easily passed on into the intestine, rather than upon any attempt to make it capable of absorption in the stomach itself. The reason is that, even under the most favourable circumstances, the stomach absorbs but little, and when it is much dilated the process is probably arrested altogether. 1 Food should, therefore, be given either in a fluid or semi-fluid form or in a state of very fine division. (4) It must be remembered that water is not absorbed by the stomach at all, and if the pyloric stenosis is complete the tissues may suffer from water starvation. In such cases it is necessary to supply the blood with fluids by another route than the mouth. (5) In all cases of dilatation of the stomach, periodic lavage of the organ is a great aid to successful feeding. In complete pyloric obstruction the patient must be fed per rectum (Chapter XXX.). An occasional saline enema, or the subcutaneous injection of salt solution, will be necessary to insure a due supply of fluids. If the obstruction be extreme, but not complete, peptonized milk should be given in small and frequent feeds. The milk may be enriched by an unfermentable sugar, such as lactose, or by the addition of one of the concentrated proteid foods (Plasmon, etc.). In cases of dilatation with comparative freedom from pyloric obstruction the diet may follow very much the lines already laid down for chronic gastritis, but even greater care must be exercised in the use of farinaceous substances and fats, and the food should be finely divided. It is better to avoid all effervescing beverages, as they tend unduly to inflate the stomach. A little hot water may be drunk immediately after meals, and also with advantage on going to bed and on first rising in the morning. 2. Non-obstructive (Atonic Dilatation). In cases of atonic dilatation the diet should be the same as for flatulent dyspepsia (q.v.). In extreme cases an exclusive proteid diet is sometimes helpful (for details see p. 553). 1 See Klemperer, Deut. Med. Woch., 1889, xv. 170, and Verhand. d. 8ten Con. f. Inn. Med., 1889, 271. FUNCTIONAL DYSPEPSIAS 5 2 9 Functional Dyspepsias. Under this heading one may group for convenience that large and heterogeneous class of cases in which digestion is performed painfully or with difficulty, but in which no organic change in the organs of digestion can be discovered. In some of these cases the chemistry of the stomach is at fault, but in many the basis of the condition would seem to consist rather in a hyperesthesia of the stomach, an undue sensitiveness to normal irritants. In treating them it is essential to keep one or two principles clearly before one's mind, (i) In many of these cases the patient's general nutrition requires to be considered rather than his mere gastric sensations. If the nervous system and blood can be raised to a proper level of health, the dyspeptic symptoms often disappear spontaneously. For this reason great harm may be done by too strict dieting. The tendency in such patients is to go on cutting off one article of food after another until a state of semi-starvation is induced, in which it is impossible for any organ in the body properly to perform its work. Instead of adopting this plan, it would be well if such patients could be induced to follow the advice of King- Chambers, and add to the diet any article of food that had once been found to agree, rather than to cut out of it anything that had ever disagreed. (2) Mental and physical rest, preferably in bed, is a great and sometimes indispensable aid to treatment. It acts both by economizing vascular and nervous energy and by enabling nutri- tion to be efficiently carried out upon a minimum quantity of food, and therefore with the least amount of labour on the part of the digestive organs. (3) In no class of gastric disorders does the question of idiosyncrasy play a greater part than in this. Due regard must therefore always be paid to the inclinations of individual patients in arranging the diet-sheet. In all cases of this class the same elementary dietetic rules must be observed as in other forms of digestive trouble. The food must be in a suitable physical form, all notoriously indigestible articles being avoided ; the meals should be properly arranged, and chewing carefully performed. To these simple directions one need only add that good cooking and attractive presentation of the meals are here of the first importance. In all cases the most easily digested foods should be selected, these being : 34 530 FOOD AND DIETETICS (a) Meats: Mutton, venison, sweetbreads, chicken, tripe, rabbit, grouse, partridge, .pheasant. (6) Fish : Whiting, sole, turbot. (c) Farinaceous foods : Stale white bread, rusks, plain biscuits, rice, tapioca, sago, arrowroot. (d) Vegetables : Asparagus, sea-kale, spinach, cauliflower, French beans. (e) Fruits : Baked apples, or the juice of oranges or grapes. ' Made dishes,' twice-cooked meats, sauces, pastry, pickles, cheese, sweets and preserves should be avoided altogether. Meat should be underdone ; fish should be boiled or steamed. The special rules of diet will depend upon the particular form of dyspepsia with which one has to deal. For practical purposes one may distinguish the following varieties : i. Defective secretion (hypochlorhydria and achylia). 2. Excessive secretion (hyperchlorhydria). 3. Defective motility ('atonic' dyspepsia). 4. Excessive sensibility (gastralgia). The principles to be observed in prescribing rules of diet in each of these forms may now be briefly discussed. 1. Defective Secretion. — In cases of this sort the mechanical form of the food is of much greater importance than its chemical composi- tion. So long as the motor power of the stomach is unimpaired the defect of secretion is not of much account, for digestion will be fully performed in the intestine. The food should therefore be finely divided (pounded, minced, or sieved), in order to facilitate its passage through the stomach, and thorough mastication insisted upon. If this principle be observed an ordinary mixed diet may be safely prescribed. Even when secretion is completely arrested (achylia) this may be done without risk, unless there is evidence of proteid decomposition in the intestine, as shown by offensive eructations or a tendency to diarrhoea. In that case meat should be strictly limited in amount, or even abolished from the diet altogether, its place being taken by peptonized milk and the casein preparations (e.g., Plasmon). 2. Excessive Secretion. — Much discussion has taken place as to whether the diet, in cases of hypersecretion, should be mainly animal or vegetable in constitution. 1 On the one hand, there is no doubt that an animal diet ' fixes ' the excess of hydrochloric acid most efficiently, whilst on the other there is abundant evidence to show that in the long-run a mainly vegetable diet leads to a permanent diminution of acid formation. An animal diet is there- fore the best palliative, whilst a vegetable diet is more strictly curative in effect. The writer's own experience is that in practice 1 See Schloss, ' Vegetabilische oder Fleischnahrung bei Hyperaciditat ' {Arch, f. Verdauungs Krankh., 1907, xiii. 233), FUNCTIONAL DYSPEPSIAS 531 a predominatingly animal diet gives the best results, whilst other means may be relied upon for actually lessening secretion (e.g., the free use of fats, administration of bismuth, etc.). On the other hand, it is reasonable to exclude all direct stimulants of secretion. Under this heading come such substances as common salt, extractives of meat, the various condiments, and alcoholic beverages. As there is both experimental and clinical evidence 1 to show that fats have a restraining influence on gastric secretion they should be partaken of freely. As much as an ounce of almond oil may be given before meals with advantage, especially in cases complicated by ulceration. Foods rich in carbohydrates, on the other hand, must be eaten sparingly, as free acid appears in the stomach very early after their use, and the conversion of their starch by the saliva is interfered with. For this reason the addition of malt to farinaceous foods is often of great service in cases of hyperacidity. Cane sugar being a potent excitant of secretion should be avoided altogether. It is particularly harmful in cases of acid gastritis. It stands to reason that where ' acidity ' of the stomach is complained of, all sour articles should be banished from the diet. Vinegar and some wines are examples in point. The application of the above principles may be expressed in the following rules : Directions for Diet in Hyperchlorhydria. 1. The diet should consist mainly of animal constituents (milk, eggs, fish, and meat). 2. Salt, pepper, mustard, meat extracts, gravies, meat soups, spices, pickles and condiments should be altogether avoided. 3. Bread and potatoes should be taken very sparingly, but bacon and butter may be eaten freely. 4. Sugar and all sweet or sour things should not be eaten. 5. Alcoholic beverages should be avoided. The best drink at meals is an alkaline water such as Apollinaris. 3. Defective Motility (Atonic or Flatulent Dyspepsia). — In this form of dyspepsia the mechanical form of the food, as in cases of defective secretion, is of chief importance. It is essential to avoid burdening the stomach with large quantities of material, especially such as is of a bulky sort (e.g., green vegetables). The simultaneous presence in the stomach of solids and liquids is specially injurious, for in such circumstances the fluid part of the meal is retained for a long time in the organ, and tends to dilate it by its mere weight. The meals 1 See Backman (Zeit. f. Klin. Med., igoo, xl. 224), and Craven Moore and Ferguson (Proc. Roy. Soc. of Med-, Laryng. Sect., 1909, iii. 25). 34—3 532 FOOD AND DIETETICS should therefore be dry, and care should be taken not to drink for at least two hours after solid food has been taken. If flatulence be much complained of — as it often is — green vege- tables and the pulses should be avoided altogether, on account of their ' windy ' tendency, and the starchy foods should be strictly limited. The necessity for reducing the starches in flatulence is a principle derived from experience for which it is difficult to find a satisfactory reason. It certainly does not reside in the ' fermentable ' character of starchy food, for the flatulence of atonic dyspepsia is almost certainly not due to fermentation, but there is no doubt about the practical harmfulness of the carbohydrates, explain it how one may. Restriction of fluids is also of special importance in cases of flatulence, tea, especially, being peculiarly noxious to these patients. On the other hand, it is in atonic dyspepsia that the moderate use of alcoholic beverages at meals, preferably in the form of a little sound wine, often gives the happiest results, for alcohol is a stimulant both to the secretory and motor functions of the debilitated stomach. The above general principles may be summed up in the following directions : Directions for Diet in Atonic and Flatulent Dyspepsia. i. The following articles should be avoided : Green vegetables (except spinach and cauliflower tops) ; turnip and carrots ; peas, beans, and lentils ; fruits (except the pulp of baked apples or stewed prunes) ; sugar and jam ; soups. 2. Potatoes should be taken very sparingly. 3. Crisp toast, rusks or pulled bread should be taken in place of ordinary bread. 4. As little fluid as possible should be taken at meals. A little hot water may be sipped between meals if flatulence is troublesome. 5. Tea should be avoided entirely, and coffee only taken with plenty of milk. The above rules are applicable in all cases of atonic dyspepia of moderate degree. In severe cases, however, in which there is pro- nounced dilatation of the stomach (non-obstructive), an 'exclusive proteid diet ' is sometimes indicated. Such a diet is described in detail elsewhere (p. 553). Far more commonly one has to deal with cases in which the gastric atony is merely part of a general condition of neurasthenia, and it is then often complicated (especially in women) by visceral ptosis. In such cases one must ignore the gastric symptoms and improve the general state of nutrition at all costs, for it is only when this has been accomplished that normal digestive power returns. The best way of doing this is by a course D1ARRHCEA 533 of over-feeding combined with rest in bed and massage (Weir Mitchell treatment or rest-cure). For details of such treatment see p. 511. 4. Hyper-sensibility of the Stomach (Gastralgia). — The diet here must be of a ' bland ' character, such as is suitable in the early stages of gastric ulcer (see p. 524). Rest in bed greatly facilitates the use of such a plan. So soon as pain disappears a liberal mixed diet should be adopted in order to improve the state of the blood and the general nutrition of the patient. Red meat should be given as early as possible, particularly as patients who suffer from gastralgia are often anaemic and debilitated from the habitual use of a poor diet defective in proteid. If these principles be observed no special rules will be required. Diseases of the Intestines. In acute diarrhoea the chief point to be aimed at in feeding is to select a diet which shall be unirritating, and shall leave as small an unabsorbed residue as possible. If the diarrhoea be very severe, it may be necessary to withhold all food for a day or two, nothing being given by the mouth but a little barley-water to quench thirst. When the symptoms have somewhat abated, and in milder cases from the outset, one can allow weak decoctions of cereal preparations, such as arrowroot, rice, cornflour, sago, or one of the patent cereal foods. These should be given at the body temperature. By-and-by one can begin to give milk, but tentatively and always safeguarded with a little lime-water. Raw-meat juice, alum-whey, egg-white solution, and the pulp of underdone beef are also useful ; but all solutions containing the extractives of meat are best avoided. If the patient be very thirsty, he may be allowed sips of cold tea or diluted red wine, or water flavoured with a little lemon-juice. In cases of chronic diarrhoea, all bulky foods and those which leave a large residue or which contain laxative principles should be avoided. Amongst such are green vegetables, fruits, and all sour things. Hot liquids should not be taken. Alcoholic beverages are best avoided. Milk must be given with caution : in some cases it increases the diarrhoea, in others not. It is safest when freely diluted with lime- water. The further details of the diet must depend upon the cause of the diarrhoea. If, for example, it be due to defective- secretion of gastric juice (' gastrogenic '' diarrhoea), the diet must be arranged as in cases of achylia (p. 530). If it be due to fermentation in the bowel, the diet must be arranged according to the nature of the fermentation. If it be the carbohydrates which are at fault, as shown by the passage of 534 FOOD AND DIETETICS acid stools, the starches must be reduced to a minimum. In such a case a diet of milk, casein preparations, and underdone meat may suit best. If, on the other hand, there is decomposition of proteids with alkaline offensive stools, meat must be withheld entirely, and the diet consist of milk and carbohydrates. If the stools are white, greasy, and show fat droplets, fat should be withdrawn from the diet, and skim milk, casein preparations, carbohydrates, and under- done meat made the basis of the regimen. In cases of nervous diarrhoea there are no special rules of diet, but the experience of the patient should be made the guide as to what to eat, drink, and avoid. In the treatment of the special form of diarrhoea known as sprue, a strict milk diet is generally recommended by the best authorities. At first 3 pints of milk are allowed daily, in hourly or two-hourly feeds. In a few days the quantity may be increased to 100 ounces a day, and after ten days to as much as 6 or 7 pints in the twenty-four hours. The strict milk diet should be continued for six weeks after the stools have become solid, after which the diet may be gradually advanced, much in the same way as in gastric ulcer. If after a period of rigid milk diet the patient is unable to return to ordinary food, a course of ' Salisbury treatment ' (p. 553) may be useful. Strawberries have been asserted to have an almost specific influence in controlling the diarrhoea of sprue, and as much as ij pounds of them have been given daily with apparent success. 1 Authorities are divided as to the best form of diet in cases of dysentery. In acute cases mild starvation is probably the best plan, beginning with thin broths and decoctions of cereals as in acute diarrhoea, and passing on to milk, either plain, peptonized, or suitably diluted, so soon as the tongue is clean. In chronic cases a more generous diet is advisable, but all coarse and irritating foods and such as leave a large residue in the bowel should be avoided. Bilberries are strongly recommended by Dernstein 2 in chronic dysentery. In acute and ulcerative colitis the diet should be the same as for acute and chronic dysentery respectively. In muco-membranous colitis two distinct plans are advocated : (1) Most French writers, influenced by their experience at Plombieres, recommend a diet which leaves as little residue in the bowel as possible, the diet consisting of lightly cooked eggs, pounded meat or fish, sieved potatoes, toast, rusks or biscuits, rice, the Italian pastes, milk, if it can be digested, and the pulp of ripe fruits. (2) Von Noorden, on 1 For an illustrative case, see a paper by Young, Lancet, March 28, 1903. a Brit. Med. Jown., February 7, 1902. MUCOUS COLITIS 535 the other hand, recognizing that constipation is an essential part of the disease, urges that the diet should be bulky, and contain much cellulose and other articles suitable for cases in which there is sluggish action of the bowels. The irritating effects of such a diet are obviated by adding to it large quantities of fat in various forms. Ransome 1 gives the follow- ing as a typical dietary which possesses the essentials of the treat- ment, but in which modifications, especially in quantities, must be made to suit individual cases : 7 a.m. — \ pint milk-cream mixture. 8 a.m. — \ pint Kissingen water. 9 a.m. — \ pint cocoa with cream (2 oz.), bread (2 oz.), butter, marmalade. 10.30 a.m. — Massage. 11.30 a.m. — 12 oz. special soup; 3 oz. bread; 1 oz. butter; potatoes, green vegetables, baked apple, stewed pears, or boiled gooseberries; cream. Rest for two hours with hot bottle on abdomen. 4 p.m. — i pint milk-cream mixture. 7 p.m. — Dinner like lunch, but with 3 oz. bread and 2 oz. butter, g. 30 p.m. — \ pint milk-cream mixture. A description of certain items in this dietary may be found useful. Milk-Cream Mixture. — This consists of equal parts of milk and cream, and one teaspoonful of sugar of milk. The cream should contain 30 per cent, of butter-fat, and nearly a pint should be taken in the twenty-four hours. Kissingen Water. — This is used as a stomachic, not as an aperient. Bread. — This must be of the coarsest flour obtainable. The larger proportion of husk it contains the better. The usual brown bread sold as whole- meal bread is not sufficiently coarse. Butter. — The average total quantity should be \ lb. a day ; 5 or 6 oz. of this is taken with bread, the remainder being used with the vegetables. Special Vegetable Soup. — This should be prepared carefully according to the following directions. Preparation of vegetable pulp : Place a breakfast- cupful of lentils or dry peas in a pan in sufficient cold water to cover them, and allow them to soak all night. In the morning add a slice of fat bacon about 6 ins. by 2 ins and J in. thick, and boil for one hour. Put one teaspoonful of butter and one of flour into a small pan on the fire, add a teacupful of milk gradually, stirring all the time until well mixed. Then add a teaspoonful of cream and mix with the pulp. To vary the flavour, a sufficient quantity of green peas, spinach, asparagus, or other green vegetable should be placed in cold water and boiled for half an hour, rubbed through a sieve, and added to the soup. The soup should contain all the husks of the peas or lentils, and should be more of the consistency of porridge than of soup. Meat.— This may be of any kind, but is more easily digested if prepared as follows : It is cut up finely with a sharp knife, and thoroughly pounded in a mortar while raw. It is then mixed with sufficient beaten-up white of egg and milk to make a thick cream, placed in a china cup, and boiled in a pan of water for three to five minutes, being well stirred during the process. Vegetables. — These should be of the coarse green varieties — cabbage, spinach, Brussels sprouts — well boiled and mashed with butter. 1 See Abst. in Ther. Gaz., November 15, 1908. 536 FOOD AND DIETETICS As the diet is rather trying at first, it is best to begin treatment with the patient in bed, preferably in a hospital or nursing home. When a natural daily evacuation of the bowels has been established, the patient is allowed to get up, and may gradually return to ordinary life and to a more usual diet, but plenty of coarse bread, vegetables and fat should remain a permanent feature of the regimen. In the acute diarrhoea of infancy all milk must be stopped for at least twenty-four hours, and nothing given but egg-white solution (the white of one egg to \ pint of water, flavoured with a little milk- sugar). Raw-meat juice and alum-whey are also very useful in such a case, and at a later stage the white of egg mixture may be made with whey instead of with water. When milk is begun again, it should be given peptonized at first, and well diluted with lime-water. The administration of salt solution, either per rectum or subcu- taneously, will often tide over the crisis in an acute case. In the treatment of constipation much can be accomplished by suitable diet. Food can increase peristalsis either by (i) mechanical or (2) chemical action. Foods which leave a large amount of residue or ' ballast ' in the intestine act in the former way. Generally speaking, all foods rich in cellulose belong to this class, e.g., oatmeal, green vegetables, wholemeal bread, and some fruits. All of these should therefore find a place in the diet. Water also acts in a large measure mechanically by increasing the fluidity of the intestinal secretion, but in part also its action may be reflex. It is best given cold the first thing in the morning. In districts in which the water contains much lime a pure artificial aerated water should be taken instead {e.g., Salutaris). Fats and oils, too, act as mechanical lubricants, and sufferers from constipation should partake of all of them freely, especially if the motions are small and dry. Honey, treacle, and marmalade have also a slightly aperient action. The chemical action of foods is usually brought about by the organic acid which they contain. It is probable, indeed, that foods rich in cellulose owe their laxative properties largely to the fact that they are very apt to undergo fermentation in the intestine, with the production of lactic, acetic, and other acids. Fruits are, of course, the foods richest in organic acids, and should always be freely used in such cases. They may be taken either fresh or stewed, figs and prunes being perhaps the best forms to select. Of beverages, cider has a decidedly laxative action, though it is apt to produce colic in many persons, and malt liquors sometimes act similarly. On the other hand, red wines are usually astringent, DISEASES OF THE LIVER 537 and so often is sherry. Milk is also a very constipating fluid, and so are tea and coffee to some persons. At least 3 pints of liquid should be taken in the course of the day. These principles are expressed in the following rules for patients : Directions for Diet in Chronic Constipation. 1. The following foods should be partaken of freely : Porridge made from medium oatmeal ; whole-meal bread ; gingerbread and ' ginger snaps '; green vegetables ; fruits (fresh or stewed — especially stewed prunes or figs and baked apples) ; marmalade, honey and treacle. Fats — e.g., bacon fat, butter, salad oil. 2. The following should be avoided : Milk ; eggs ; strong tea and coffee ; red wines. 3. A glass of cold water should be taken on rising, and a few French plums may be eaten before going to bed. Diseases of the Liver. In the dietetic treatment of hepatic cirrhosis the first indication is to counteract the tendency to gastric catarrh, which almost always co- exists along with the derangement of the liver even if it be not causally related to the latter. The most suitable diet, therefore, will be one which follows very much upon the lines of that already laid down for cases of chronic gastritis. Seeing that the liver cells also serve as storehouses for fat and glycogen, it will be well also that all rich, fatty foods should be avoided, and that carbohydrates, particularly sugar, should be eaten very sparingly. Alcoholic beverages should be strictly forbidden, except, perhaps, in the very latest stages of the disease, and all spices and condiments must also be looked upon as harmful. There are but few indications to be met in the dietetic treatment of cases of gall-stones. Seeing that the taking of food into the stomach stimulates the expulsion of bile, it will be well to see that the meals are rather frequent — at least five being taken in the course of the day. There is no scientific justification for qualitative alterations of the diet, however, for it does not seem that the inges- tion of food containing much cholesterin or salts of lime appreciably influences the composition of the bile, 1 even though it might seem on a priori grounds that such articles would be likely to promote the formation of calculi. On the other hand, most clinical observers are agreed that the drinking of large quantities of water is advisable, even although there is no actual experimental evidence to show that the fluidity of the bile is increased thereby. 1 See Aldor, Ziit. f. Physik. und Didt. Therapie, 1903, vii, 201. 535 FOOD AND DIETETICS In cases in which jaundice is a prominent symptom the consump- tion of fats should be greatly restricted, for if bile is not entering the intestine freely, the absorption of fat is interfered with, the result being that it not only retards the digestion of the other constituents of the food, but itself undergoes bacterial decomposition, with the production of irritating fatty acids. The diet should be of a simple character, and may, with advantage, contain plenty of fresh vegetables and fruit. Milk, on the other hand, should be avoided or only given f skimmed, or whey may be substituted for it. In cases of ' biliousness ' — a condition which is perhaps due to functional disorder of the liver — milk, eggs, and all rich and greasy foods should be avoided, and meat taken sparingly. The diet may consist of the white meats, and fish, toast, vegetables, and fresh and stewed fruits. Alcohol should be forbidden entirely. In chronic cases the diet should be the same as for chronic gastritis (q.v.). 4. Disorders of the Circulation. The consideration of the dietetic treatment of cardiac disease follows naturally upon that of digestive disorders, for no two organs are in closer sympathy than the heart and the stomach, and by lightening the work of the latter one indirectly aids the former. When the heart's action is impaired, the diet should be easily digested and non-flatulent, and the food should be given in small quantities at a time at not too short intervals, and should be rather dry. The limitation of fats is also quite as important as in cases of dyspepsia, for there is reason to believe that fats are badly absorbed in cases of severe cardiac disease. 1 Carbohydrates must also be used very sparingly, owing to their tendency to produce flatulence. Hence it is that the diet of cardiac disease must be pre-eminently nitrogenous in its nature. The object of all this is to prevent overdistension of the stomach, which is apt to be followed by embarrassment of the heart. In the main, therefore, the same principles must be attended to as in the dietetic treatment of dyspepsia. 2 1 See Grassmann, Zeit. f. Klin. Med., 1889, xv. 183, 2 G. W. Balfour ('The Senile Heart,' p. 240) lays down the following dietetic rules for patients with weak hearts : i. There must never be less than five hours between each meal. ii. No solid food is ever to be taken between meals. iii. All those with weak hearts should have their principal meal in the middle of the day. iv. All those with weak hearts should have their meals as dry as possible. DIET IN CARDIAC DISEASE 529 The value of a dry diet in cardiac disease has been specially in- sisted upon by several writers. 1 Its beneficial action is probably exercised in several ways : (i) In cardiac disease fluids are absorbed very slowly, and are therefore apt to interfere with digestion and produce flatulence ; (2) if fluids are withheld, the blood tends to become more concentrated, and water then passes into it out of the tissues, and thus the absorption of dropsical effusions is aided; 2 (3) the sudden entrance of any considerable quantity of fluid into the circulation throws a mechanical strain upon the heart by increasing the amount of blood which has to be propelled round the circulation. Thus limitation of fluids lessens the work of the heart (see also p. 301). In cardiac dropsy, therefore, and especially if complicated by obesity, the quantity of fluids allowed should be limited to about 20 ounces per day, and not more than 5 ounces should ever be taken at one time. If much thirst is experienced, it may be relieved by sucking a few acid drops. The following is G. W. Balfour's scheme of diet for patients with weak hearts : 3 Breakfast, 8.30. About ij oz. of dry toast with butter, a lightly-cooked egg or a little white fish ; 3 to 5 oz. of tea or coffee with cream and sugar. Lunch or Dinner, 1.30 to 2 o'clock (the principal meal of the day). Two courses only, fish and meat, fish and pudding, or meat and pudding. Soups, pastry, pickles and cheese absolutely forbidden. The most digestible forms of meat or fish to be selected ; one potato or a little spinach. Any form of simple milk pudding may be taken or a little fruit. During the meal 4 to 5 oz. of hot water may be sipped if desired. Tea, 5 to 6 o'clock. 3 or 4 oz. of weak tea with cream and sugar, but no solid food. Supper, about 7 o'clock. Must always be a light meal. May consist of white fish and a potato, or toast with butter, or some milk pudding or bread and milk. 4 or 5 oz. of hot water may be taken at bedtime. In the treatment of the flatulence, which is often such a distressing accompaniment of heart failure, especially when associated with emphysema, the meals should also be small and dry. Biscuits or rusks should be substituted for bread, and lemon-juice for vegetables. 1 See Oertel, Leyden's ' Handbuch der Ernahrungstherapie,' Bd. ii., p. 55 et seq. ; also Cheadle, Lancet, 1877, ii. 758, 794, 838, 877 ; Dickinson, Clifford Allbutt's ' System of Medicine,' v. 690 ; and Balfour, ' The Senile Heart,' chap. x. 2 Cheadle particularly insists upon the importance of limiting the intake of fluids in cases of ascites, even when due to cirrhosis {Lancet, 1900, i. 903). 3 Op, cit., p. 246. 54° FOOD AND DIETETICS Meat should be only once cooked, and rather underdone, and all soups, sauces and fruits should be avoided. While some such diet as the above may be adopted with advantage by patients with weakness of the muscular substance of the heart, it must be remembered that in cases of acute cardiac disease, and often enough where there is severe impairment of compensation, and con- sequently great interference with digestion, it may be necessary to have recourse to fluid diet, milk or peptonized milk being given in small quantities at short intervals of time. The dietetic treatment of aneurysm requires a word of mention. Our object here must be to diminish the force of the heart and to increase the coagulability of the blood. Valsalva claimed that he was able to do this by a process of starvation. He used only bread and water or pudding and water, giving as little as half a pound of pudding night and morning. His patients often became so weak that they were unable to sit up in bed. Some good observers have spoken highly of this method, 1 but for the most part it is now but rarely adopted. Tuffnell's diet for aneurysm is somewhat less severe, and can be followed out for longer periods. He allowed 4 ounces of bread-and- butter, 2 or 3 ounces of meat, 4 ounces of milk, and 3 or 4 ounces of claret, daily. Here again the chief characteristic of the diet is its extreme dryness. In cases of high arterial tension secondary to chronic nephritis, the diet must be the same as in that disease (p. 543). In primary cases of high tension, diet is often of little use in treatment, but it may be necessary in gross feeders to reduce the total intake of food and especially of meat. Alcohol is probably best avoided, and in the main the diet may follow much the same lines as in renal cases. It will often be found, however, I think, that sufferers from primary high tension have always been abstemious people, and for such, of course, dietetic rules are of no use. 5. Renal Disease. In the dietetic treatment of renal disease the principles chiefly to be borne in mind are : (1) To diminish the amount of work thrown upon the kidneys ; (2) to avoid all ingredients in the food which, during their excretion, are calculated to irritate the diseased organs. 1. As the kidneys are the chief route for the excretion of the products of nitrogenous waste, the former of these principles involves * See King Chambers, ' Lectures, chiefly Clinical,' lecture xxiv. DIET IN RENAL DISEASE 541 that the diet should be not too rich in proteids, 1 and should, as far as possible, be free from nitrogenous extractive matters. We shall see immediately, however, that as regards chronic renal disease, at any rate, the former of these indications may sometimes require to be overridden by more pressing considerations. The amount of salt in the food should also be diminished as far as possible, for the burden of excreting it falls entirely upon the kidneys. 2. Amongst the substances calculated to irritate the kidney in the process of their execretion are such articles as spices, mustard, pepper, curry, ginger, radishes, and perhaps asparagus. Alcohol, especially in concentrated forms, is also strongly contra-indicated in most cases of renal disease for the same reason, and of non-alcoholic beverages ginger ale should be avoided, owing to the fact that it contains either ginger or capsicum or both. In acute renal disease an exclusively milk diet is, by common consent, the best method of treatment. That this is not a mere general impression is proved by the fact that in such cases a milk diet is found to increase the elimination of urea and other solids, and to decrease the amount of albumin in the urine. 1 It must be remembered, however, that milk is a bulky food, and by introducing much fluid into the circulation it increases vascular tension, throws a strain upon the heart, and aggravates the tendency to dropsy. The quantity allowed should therefore be restricted to three pints a day, and the nutritive value of the diet raised by the addition of cream or other fatty food, or by allowing moderate quantities of one of the more starchy cereals, such as rice. The milk may be given either plain or, what is better, diluted with same alkaline mineral water, and if the patient tires of it kephir, or butter-milk may be used as a partial substitute. The beneficial effects of milk cannot be altogether due to the fact that it is poor in proteids. As a matter of fact, relative to its other constituents, milk contains a very considerable proportion of nitrogen. It is not improbable that its advantages are to be partly attributed to the chemical peculiarities of casein, and to the fact that on a milk diet intestinal putrefaction is reduced to a minimum. The addition to the milk diet of substances containing only carbohydrates and fats, 1 The belief that a liberal supply of proteid is required in renal disease in order to make good the albumin excreted in the urine is baseless. Assuming an average excretion of 4 per cent, albumin, the daily loss would not amount to more than 8 grammes, and would be covered by the proteid contained in the whites of two eggs. » See Ralfe, Trans, of the Med. Soc, 1894, xvii - 25 1 - 542 FOOD AND DIETETICS as above recommended, is open to no theoretical objection, and might perhaps be more extensively adopted in practice. In subacute nephritis the prolonged nature of the complaint necessitates a more solid diet. The principle of keeping the propor- tion of proteid as low as possible (certainly not more than ioo grammes daily) must still, however, be maintained. The more nearly the case stands to the acute form the more extensively should milk be used as the chief source of proteid, but in the more chronic forms of the disease other animal foods may be allowed in small quantity. It is the custom to select from these the white meats, such as fish, chicken and veal, as preferable to the dark meats. This preference is based upon the belief that the former contain less nitrogenous extractive matter than the latter. That this is true as a chemical fact has been denied by Von Noorden and others, 1 and recently the matter has been put to a practical test by Pabst. 2 He compared the amount of albumin in the urine of patients with subacute nephritis (large pale kidney) on (i) milk diet, (2) a diet containing £ pound of chicken or veal, (3) a diet containing a similar quantity of ordinary meat, with the following results : AVERAGE DAILY EXCRETION OF ALBUMIN. First Case. Diet. First Second Experiment. Experiment. Milk 145 i5'i 129 130 127 121 127 114 134 Ordinary meat I2'9 124 131 Milk I20 io - 9 124 130 89 I2'2 He concludes that the kind of diet had no appreciable or constant influence upon the composition of the urine or the amount of albumin which it contained. Other observers have recently obtained similar results. 8 It must be remembered, however, that the white meats, and especially fish, are, weight for weight, poorer in proteid than the- 1 See Verhand d. ijten Cong. f. Inn. Med., 1899, 386, and Offer and Rosenquist, Berlin. Klin. Woch., 1899, xxxvi. 937, 968. 2 Berlin. Klin. Woch., 1900, xxxvii. 547. For earlier experiments of a similar kind, see a paper by Hale White (' On the Influence of Various Diets upon the Composition ot the Urine and the General Condition of Patients suffering from Chronic Bright's Disease ') in the Med. Chir. Transactions, 1894, lxxvi. 279. 8 See Kaufmann and Mohr ■ Beitiage zur Diat^tik ^er Nierenkrankheiten,' Zcit.f. Klin, Med., 1902, xliv. 441. ' CHRONIC NEPHRITIS 543 others, and therefore if one wishes to keep the amount of nitrogenous matter in the diet low there may still be advantage in having recourse to them, although it must be admitted that the recent observations just quoted tend to show that the dark meats may not be so harmful as was supposed, provided they are used in moderation. 1 It is probable, too, that the same diet may not suit all patients equally well. Sparks and Mitchell Bruce, 1 in a case very similiar to those of Pabst, certainly found that milk gave better results than anything else. One may therefore require to feel one's way in selecting the most suitable diet. The non-nitrogenous constituents of the diet in subacute nephritis call for less consideration. Fats and carbohydrates in the form of cream, cereals, vegetables, and fruits, may be freely allowed, but alcohol and all irritating substances should, as in all renal cases, be avoided. In arranging the diet for cases of chronic nephritis, regard must not be paid too exclusively to the requirements of the kidney. Important as it is to reduce the nitrogenous waste matters in the urine as much as possible, this must not be done at the expense of other organs. The maintenance of a due degree of cardiac hypertrophy and increased vascular tension, which are essential to the occurrence of proper excretion in chronic renal disease, requires that the amount of proteid in the food should not be too rigidly limited. On the other hand, an undue increase of blood pressure, which may be induced by a too highly nitrogenous diet, and especially, perhaps, by one which is rich in extractive matters, is itself a source of danger, as predisposing to arterial degeneration and to apoplexy. It will be obvious from all this that the proper dietetic management of a case of chronic Bright's disease often requires careful steering. If there be too little proteid in the food, cardiac compensation may break down and uraemia result ; if there be too much, the patient is exposed to all the risks and inconveniences of excessive vascular tension. For the former reason milk is not suited to constitute the sole source of proteid in the diet of such cases ; for the latter the excessive use of meat is also to be deprecated. As a general rule, perhaps, one may say that the more the secreting tubules, as opposed to the glomeruli, are involved, the less proteid should the food contain ; but for the majority of cases the most appropriate diet is that re- commended for gout, i.e., one which is only moderately rich in proteid, 1 See also Senator, Berlin. Klin. Woch. 1899, xxxvi. 990. 2 Med.-Chir. Trans., 1879, lxii. 243 ; see also Prior, Zeit. f. Klin. Med., 1891, xviii. 72. 544 FOOD AND DIETETICS and that derived largely from vegetable sources, and from which spices, soups, and all preparations containing the extractives of meat are excluded. In cases of subacute and chronic parenchymatous nephritis in which dropsy is a prominent feature, the use of the so-called ' salt free ' diet is often of service. It is described in detail on p. 556. Finally, a word about the use of fluids in renal disease. It was laid down as a rule by Bamberger- that in no form of kidney affection should fluids be restricted unless diarrhoea was present. Recently this dictum has been criticised by Von Noorden, 1 who states that if dropsy has occurred, and the secretion of urine is scanty, great benefit may be derived from limitation of fluids, especially if there be cardiac dyspnoea and threatening heart failure. He says that long-continued observations by himself and his assistants have quite failed to show that the products of nitrogenous waste are not well excreted under such a plan, and cites several cases in which it wrought great improvement. On the other hand, he recommends that if diuresis has already set in fluids should be freely allowed, even although cedema be still present. It must remain for further clinical experi- ence to substantiate these conclusions, but in cases of high vascular tension, at all events, the sudden entrance of a considerable quantity of fluid into the circulation must always be apt to be injurious, and in such circumstances, whether the total daily supply of fluids be limited or not, 2 it is wise to forbid the consumption of a large quantity at one time. The habitual use of alcoholic beverages should be avoided as far as is practicable in cases of chronic nephritis, unless they are imperatively indicated for the sake of the heart. ' A sufferer from atrophic nephritis,' says Von Noorden, 3 ' should be instructed by his physician that alcohol, unless prescribed as a medicine, is for him a dangerous poison. If he insists upon taking it, he does so at his own risk.' In practice these principles may be applied in the following rules : Directions for Diet in Chronic Nephritis. 1. The following are harmful and should be absolutely avoided : Soups made from meat ; gravies ; sauces ; spices {e.g., mustard, pepper, ginger, curry, nutmeg or cloves). 1 ' Diseases of Metabolism and Nutrition,' Part II., Nephritis. English edition (Bristol : John Wright and Co., 1903). 8 Von Noorden recommends that the total amount of fluid allowed in the diet in cases of chronic nephritis should not exceed 1 J litres (about 2 pints) per day. He goes so far as to say that in many cases of contracted kidney such a restric- tion may save life. s Op. cit. DIET IN NERVOUS DISEASES 545 The following vegetables : Radishes, celery, asparagus, rhubarb. Alcoholic beverages. 2. Tea and coffee should be taken in strict moderation. 3. The animal ingredients of the diet should be restricted to 1 egg, 1 pint of milk, one helping of meat (4 oz.) and one of fish daily. 4. The total amount of liquid taken should not exceed 2 pints daily. Diet in Diseases of the Nervous System. Dietetic means are of comparatively little value in the treatment of nervous diseases. In most of such cases the food must be adapted to the condition of the patient's other organs. In many cases of neurasthenia it is important to improve the state of the patient's nutrition by adopting the plan of feeding already described in the section on 'fattening up' (p. 511), and for all nervous subjects fat seems to be one of the most important nutritive constituents of the food, and it is often important to preach to such patients what has been described as ' the gospel of fatness.' The question of the most suitable diet in cases of epilepsy has led to much discussion, some writers recommending abstention from meat in that complaint, whilst others put a strict bar upon the use of alcohol. Schloss has recently 1 investigated the subject afresh, and concludes, as the result of his clinical experiments, that the nature of the diet adopted has no appreciable influence either on the number or the severity of the fits. Nor did he find that the use of alcohol could be shown to be in any way harmful. The value of reducing the amount of common salt in the diet of epilepsy and of substituting for it bromide preparations has also been insisted upon by some writers. 8 Schloss, in investigating this point, found that by selecting a diet containing but little sodium chloride he could reduce the consump- tion of that salt to about 30 grains a day, replacing it by 60 grains of mixed bromides. Under this treatment the fits became fewer and less severe, but the patient steadily went down in weight and strength. Aldren Turner 3 believes thai a purin-free diet (p. 551) is sometimes useful in epilepsy, especially in recent cases in which the seizures are of the major variety. It is certainly always worth trying. 1 ' Ueber den Einfluss de Nahrung auf den Verlauf der Epilepsie,' Wiener Klin. Woch., 1901, xiv., No. 46. 2 See Balint in Berlin. Klin. Woch., 1901, xxxviii. 617. A review of other results will be found in an article by Dr. Purves Stewart in the Med. Annual for 1904 (p. 314). 8 Practitioner, 1906, lxxvi. 470. 35 546 FOOD AND DIETETICS In cases of chorea the diet should be of a fattening character (p. 511), cream and other fat-containing foods being given liberally. Where fluid food can alone be taken, milk, beaten-up eggs, and strong soups should form the basis of the diet. These constituents may be enriched by the addition of casein preparations, cream, and some of the numerous cereal foods. In Graves' disease there is some reason to believe 1 that meat is harmful, and a vegetarian or lacto-vegetarian diet gives the best results. The food should be nourishing and contain plenty of fat. Alcohol, tea and coffee should be avoided. In the treatment of headaches — especially of the periodic migrainous or bilious variety — diet is sometimes of great help. In certain in- dividuals, particular articles of food may apparently cause such headaches by acting as direct poisons. Amongst such articles are tea,- sugar and eggs. More often it is necessary to make radical alterations in the diet as a whole. In well-nourished patients a decided limitation of the • carbonaceous ' foods as recommended by Dr. Hare (for details see p. 552) is often successful. Others do well — for a time at least — on a purin-free diet (p. 550). In yet others, vegetarianism gives good results, or at all events a great reduction in the intake of animal proteid (meat) on the lines advocated by Chittenden. In every case it is necessary to individualize, and to take into consideration the condition of the vital organs and the state of the patient's general nutrition, for in some cases — particularly when the headache is of a neuralgic character — a cure only results when the level of nutrition has been raised by a judicious course of fattening (p. 511). Diet in Diseases of the Skin. There are four ways in which diet may conceivably influence the skin: 2 (1) By affecting general nutrition; (2) reflexly from the alimentary canal ; (3) by giving rise to the absorption into the blood of irritating or decomposition products ; (4) by the elimination through the skin of certain constituents of the food. It must be admitted, however, that when we come to use dietetic methods in the actual treatment of cutaneous disorders, we find our- selves greatly hampered both by our ignorance of the precise part played by diet in any given case, and by the always unknown factor of personal idiosyncrasy. So much is this the case that it may be 1 Hanna Thomson, Amer. Journ. Med. Sci., 1908, cxxxv. 313. a Walter Smith, Brit. Journ of Dermat., 1898, vii. 328, DIET IN DISEASES OF THE SKIN 547 said without fear of contradiction that there are but few diseases of the skin in which treatment by diet is of much value, and that the potentialities of this line of attack are much less promising than patients generally believe. In the great majority of cases of skin disease, therefore, either no special rules of diet are required at all, or they must be drawn up with reference to the patient's general condition without regard to the state of the skin. There are a few cutaneous diseases, however, in which diet may be of some direct help, and these may be briefly considered. Eczema. — In very acute cases in which the patient is really ill, an exclusively milk diet may be required for a time, and in any case the more marked the local inflammatory signs are, the simpler should the diet be. In chronic cases it is customary to forbid sugar and to recommend a liberal use of green vegetables, but in both instances on no very satisfactory grounds. On the whole, the diet in chronic eczema should conform to the principles of ' simplicity and temper- ance,' and may, in details, be the same as for chronic gout (p. 518). Alcohol is usually harmful. In psoriasis various ' systems ' of diet occasionally meet with success. Bulkley 1 recommends absolute vegetarianism, forbidding even milk and eggs, and says he has seen the worst cases disappear under such a plan, whilst per contra the quite opposite regimen of meat and hot water only, 2 or an exclusively milk diet, has proved successful in the hands of others. In the majority of cases, diet has probably little or no influence. In rosacea the diet should be arranged to meet any form of dyspepsia which may be present (p. 529), but alcohol, tea, coffee, spices, and anything which causes flushing of the face must be rigidly excluded. In pruritus, especially of the anus or vulva, all highly-seasoned, salted, or preserved foods should be avoided, besides alcohol and coffee, and the diet restricted to the white meats, toast, green vegetables, and light milk puddings. Should diabetes be present, the dietetic indications are, of course, the same as for that disease (p. 488). In urticaria much may be effected by diet if one can discover — not always an easy task — the peccant ingredients of the food. Amongst the most frequent offenders are shell-fish, mushrooms, 1 Journ. Amer. Med, Assoc, 1908, February 22. 2 Parkes, Lancet, 1874, i. 722 ; an4 Malcpljn Morris, Practitioner, 1906, lxxvi. 575. 35- 7, 548 FOOD AND DIETETICS pickles, pork, eggs, cheese, oatmeal, strawberries or other fruits, and sour wines, but almost any article of food may cause it if an idiosyncrasy be present. I have also known patients to be cured by adopting vegetarianism for a time. In concluding this section, one cannot do better than quote the wise words of an eminent dermatologist: 1 'After all, it is in com- paratively few cases of skin disease that the diet is really of any particular importance. . . . Put not your faith in printed dietaries, or indeed in any general formularies. Above all, remember that the patient has larger and better opportunities of observation than the doctor, and, if he is a person of ordinary intelligence and self-control, he should be trusted. The doctor who attempts to dictate as an oracle in the matter of diet is like Lord Foppington's bootmaker, who insisted that he knew better than his client whether or not the shoe pinched.' 1 Malcolm Morris, he. tit., p. 584. t 549 3 CHAPTER XXIX SOME DIETETIC ' CURES ' AND ' SYSTEMS ' In the earlier part of this book reference has been made to the so-called milk (p. 130), whey (p. 132), koumiss (p. 143), and grape (p. 256) ' cures.' In the present chapter I propose to deal briefly with some of the more elaborate ' systems ' of diet which are some- times useful in the treatment of disease. That such systems are occasionally of great therapeutic value no one can deny, but they must be used discreetly, bearing in mind the dangers and fallacies inherent in all attempts to treat disease on a ' system,' regardless of the peculiarities of the individual case, and remembering that no such system can ever be a panacea, but is at best of restricted, and often only of temporary, value. The reckless and uncritical advocacy of the faddist can only serve to bring such systems into disrepute. Vegetarian and Lacto-vegetarian Diet. In a previous chapter (p. 172) the question of vegetarianism was discussed in detail, and the conclusion arrived at that it was not a form of diet which is to be unreservedly commended for healthy persons. None the less, as a mode of treatment in certain cases of disease, such a regimen is deserving of the careful consideration of the medical profession, and all the more that hitherto it has been mainly exploited by the large body of ' amateur ' practitioners. There are certain well-recognized peculiarities and properties of a non-flesh diet which justify the expectation that it will prove of use in some morbid states. In the first place, such a diet is compara- tively free from the purin-bodies, the share of which in the produc- tion of gout has already been discussed (p. 517), besides containing almost always less total proteid than a mixed diet. In the second place, a diet from which flesh is excluded, and which contains a large proportion of milk, tends greatly to restrain the process of putrefac- 55o FOOD AND DIETETICS tion in the intestine. Now, there is some reason to believe that certain obscure conditions of general ill-health, and in particular some cases of neurasthenia, are produced and maintained by the absorption of such putrefactive products. In the third place, such a diet is peculiarly rich in mineral salts, and although the part played by these in metabolism is at present but ill-understood, there is yet reason to believe that by altering the ' balance ' of the salts in the body nutrition may sometimes be influenced for good. In the last place, a diet which is of mainly vegetable composition leaves a large residue in the bowel, and so tends to counteract the prevail- ing modern tendency to constipation, with all its attendant evils. Much careful observation and clinical experiment will certainly be required before we are able clearly to discern exactly in what cases a diet of this sort is likely to be of benefit, but meantime the follow- ing list of diseases in which there is at least presumptive evidence that a vegetarian or lacto -vegetarian regimen exercises a curative influence may be tentatively put forward. 1 (i) Corpulence complicated by constipation in middle life. (2) Certain cases of alcoholism. (3) Some forms of functional dyspepsia and intestinal affections of nervous origin. (4) Idiopathic neuralgias and those having a gouty basis. (5) Headaches and other disorders dependent on constipation in neurasthenic, hysterical, and epileptic patients. (6) Conditions . of abnormal irritability of the heart of nervous origin and in exophthalmic goitre ; but not heart-weakness due to arteriosclerosis and myocarditis. (7) Many cases of nervous insomnia. (8) Some varieties of disease affecting the skin. It is almost always advisable to make the change from an ordinary diet gradually, and in many cases it is inadvisable to continue the vegetarian plan for longer than six weeks at a time. The Purin-Free Diet. Purins are a series of bodies which contain the nucleus C 5 N 4 , and which on oxidation yield two molecules of urea. They may be classified as : (1) Oxy-purins (hypoxanthin, xanthin and uric acid) ; (2) amino-fiurins (adenin and guanin) ; (3) methyl-purins (theobromin and caffein). The purins of the food (oxogenous purins) are taken in the 1 See L. Kuttner, Berliner Klinih, January, 1902, and Albu, ' Die Vegetarische Diat ' (Leipzig, Georg Thieme, 1902), p. 130. THE PURIN-FREE DIET 551 following forms : (1) Methyl-purins in tea, coffee and cocoa ; (2) free purins, such as xanthin and hypoxanthin, in meat extract ; (3) bound purins in the nucleo-proteids of many animal and some vegetable foods. Foods may be classified according as they are rich in purins, poor in them, or free from them, as follows : 1. Rich in purins : Sweetbread, liver, beef, pork, mutton, chicken> veal, salmon, halibut, and plaice. 2. Poor in purins : Potatoes, onions, oatmeal, the pulses, turnips, carrots, parsnips, asparagus, rhubarb, sea-kale, spinach, dates, figs, codfish, and sole. 3. Free from purins : Milk, eggs, cheese, butter, sugar, white bread, rice, tapioca, cabbage, cauliflower, lettuce, macaroni, straw- berries. Amongst beverages, tea, coffee, and cocoa, and malt liquors contain purins ; wines and spirits are free from them. A diet which is practically purin-free may therefore be constructed by observing the following rules : 1 Directions for a Purin-free Diet. 1. The things to be avoided are : (a) All flesh foods (meat, fish, fowl, game, etc.) and articles derived from them {e.g., soups, sauces, gravies). (b) Peas, beans, lentils, oatmeal, asparagus, onions. (c) Tea, coffee and malt liquors. 2. The diet should be composed of vegetable foods (except those mentioned above), milk, cheese and eggs. The following is suggested as a daily menu : Breakfast : Eggs, the fat of bacon (avoiding all iean), bread or toast, milk flavoured with cocoa or a dash of coffee or tea. Any fruit, stewed or fresh. Luncheon or dinner • Soup made from vegetables (except those men- tioned above), with the addition of milk, if desired, and thickened with some farinaceous preparation or grated cheese ; one of the Italian dishes — e.g., risotto, macaroni, spaghetti, or polenta ; potatoes in any form ; any simple pudding or stewed fruit ; cheese ; salad. The change to such a diet should be made gradually.. For a week or two the non-nutritious purin-containing articles — e.g., tea, coffee, soups, beef-extracts, gravies — should be avoided, and meat and fish taken only once a day. After this probationary period is over the more strict diet may be adopted. The advantages of what was practically a purin-free diet in cases of gout were pointed out long ago by Dr. George Cheyne, 2 but in 1 The construction of such a diet is facilitated by a study of various cookery- books — eg., ' Vegetarian and Simple Diet,' by Kenney Herbert (Sonnenschein), and ' The Apsley Cookery-Book ' (J, and A. Churchill), s ' The English Malady ' (London, 1733). 552 FOOD AND DIETETICS recent times, and under its modern title, it has been specially advocated by Dr. Haig. 1 The benefits derived from its use in certain cases of disease are ascribed to the alleged toxicity of purins, which are believed to produce the following amongst other diseases : Chronic and irregular gout in all its manifestations, chronic ' rheu- matism,' migraine and periodic headaches, asthma, bilious attacks, epilepsy, catarrhs, neurasthenia and general ill-health of indefinite nature. It would be going far beyond the province of this book to discuss in detail the evidence for and against the harmfulness of the purin- bodies in food-stuffs, 2 but it may be said that whilst there can be no doubt of the fact that a purin-free diet is capable of exerting a curative effect in some at least of the above-mentioned maladies, there is equally little doubt that the therapeutic claims made for it by some of its more intemperate advocates cannot be substantiated. There is certainly no reason to believe that purins are ' poisonous ' in any real sense of the term to the vast majority of mankind, and, on the other hand, it is quite possible that some of the good effects which a purin-free diet is capable of producing are to be ascribed to something other than its poverty in these chemical compounds. As it is quite conceivable, however, that some persons have a metabolic idiosyncrasy to purins, and that in such they produce disease, the purin-free diet is always worth trying in chronic and intractable cases of the type already referred to. It will often be found, how- ever, that even in such persons freedom from symptoms is not permanent, but that the morbid manifestations recur after a time, although perhaps, in a milder form. 3 In any case, the change to such a diet should always be made cautiously, and it is not often advisable to continue it for long in its strict form, as otherwise digestive troubles and impairment of the general health are apt to result. Dr. Hare's System. Dr. Francis Hare 1 believes in the possibility of the accumulation in the blood of an excess of ' fuel ' or ' carbonaceous ' material. He 1 ' Diet and Food ' (London : Churchill), etc. s The question is discussed in the following amongst other papers : Potts, ' The Advantages of a Purin-Free Diet,' Lancet, 1905, i. 1636 ; ' Purin-Free Dietaries,' Brit. Med. Journ., 1909, i. no; Chalmers Watson, 'Has a Purin. Free Dietary any Special Therapeutic Value,' ibid., 1907, ii. 1759 ; Bryce, ' The Limitations of a Purin-Free Diet,' ibid., October, 31, 1908. 3 See Bryce, he. cit. 4 ' The Food Factor in Disease ' (Longmans, 1905), and ' The Dietetic Treat- ment of Certain Diseases in the Well-nourished and Corpulent ' (The Medical Magazine, 1907, xvi. 722). DR. HARE'S SYSTEM 553 terms this a state of hyperpyramia, and attributes to it the occurrence of many periodic disorders, such as migraine, bilious attacks, and asthma. The hyperpyraemic state can be prevented by reducing the intake of carbonaceous food, with the consequence that the periodic disorder disappears. He begins by placing the patient on a small, mainly proteid diet, consisting, say, of 8 to 12 ounces of cooked lean meat or fish, with i£ ounces of bread or toast and a little butter ; green non-starchy vegetables are permissible, also tea and coffee with a little milk but no sugar. Such a diet is usually accompanied by loss of weight. The loss is carefully estimated by frequent weighings and by slowly adding to the amount of carbohydrates and fats, preferably by cautiously increasing the allowance of bread, butter, and milk a diet is arrived at under which the weight remains stationary and carbon equilibrium is being maintained on a minimum intake. In arriving at this minimum exactitude is indispensable ; the scale of diet should be fully written out and the ingredients weighed. If one is treating a case of migraine it is advisable to begin the diet about a fortnight before the next attack is expected, and after one headache period has been passed to increase slowly the amount of starchy food until the weight is stationary. Without accepting the theoretical considerations upon which this system of treatment is based one may freely admit that it gives excellent results in many of the conditions referred to, and as it is easy to carry out it is often a valuable resource. Such a regimen, however, is only suitable in well-nourished persons, and it is in these that its most striking effects are obtained. Exclusive Proteid Diet. In this system, which is better known as'the Salisbury cure, 1 the diet consists of lean meat and hot water only. Such a diet may be spoken of as an exclusively proteid one, for although there is always a certain proportion of fat even in lean meat, yet the amount for practical purposes is negligible. This system has been recom- mended in the treatment of chronic articular gout, some diseases of the skin — e.g., psoriasis — and in certain intractable forms of dys- pepsia, especially when associated with atonic dilatation of the stomach. The following is a description of the technique of the diet as given by one of its more recent advocates : 2 1 Salisbury, ' The Relation of Alimentation and Disease,' New York, 1895. 8 Ernest Young, The Clinical Journal, 1908, xxxiii. 55. 554 FOOD AND DIETETICS ' The basis of the diet is thoroughly cooked minced lean beef (so prepared that all gristle and the greater part of the connective tissue are removed) and hot water. (Minced mutton or chicken may be substituted occasionally for variety, but bulk for bulk neither is so nourishing as the beef.) ' The minced beef is given three times a day, with a five-hourly interval between each meal. The best hours for meals are 8.30 a.m., 1.30 p.m., and 6.30 p.m. In any case the last meal should not be later than 7 p.m. ' The hot water is given four times a day, one and a half to one and a quarter hours before each meal, and three and a half hours after the last meal. The water should be sipped slowly at a tempera- ture of about 120 F. — roughly that at which tea or coffee is usually taken. The quality of the water is an important factor, and if at all hard distilled water must be used. ' The quantity of meat at each meal varies from 2 ounces upwards, the quantity of each portion of hot water being a pint, or less, according to the nature of the individual case.' The following details as to the preparation of the diet (from the same author) may be of practical help : The diet may be taken in the form of beef mince or beef cakes, the former being rather more digestible but less satisfying than the latter. Both should be prepared from ' topside ' steak, preferably from the centre of the round of beef. 1. The Beef Mince. — Take a steak, not less than an inch thick, free it from fat, place in a frying-pan — previously rubbed with a little butter to prevent sticking — and cook quickly (turning occasionally) over a clear, sharp fire until it is almost half done. Allow it to cool, then cut into strips and pass three or four times through an ' Enterprise ' mincer. Place the minced meat in an enamelled or aluminium saucepan, add a little water (about a teaspoonful to 1 ounce of meat is the average quantity) and beat to a smooth, stiff pulp with a wooden spoon ; it must never be watery. Place the saucepan on an asbestos cooking-mat upon a cool part of the stove and cook slowly, stirring and turning over the mince constantly until the red colour disappears and it is thoroughly brown. This will take from fifteen to twenty minutes for a small quantity. If properly prepared at a gentle heat, the mince will be quite smooth and of the consistency of soft dough. If it is granular, it shows it has been cooked too quickly, and must be rejected. 2. The Beef Cakes. — Pass strips of raw steak three or four times through the mincer. Place the minced meat on a plate, flatten out with a fork, and add a little water. By means of two forks quickly shape the meat into a round, flat cake about 1 inch thick, touching the meat as lightly as possible, just sufficient to make it hold together. Place the 'cake in an ' Enterprise ' griller, previously rubbed on both sides with a little butter. Hold the griller about 8 inches above a sharp, clear fire, turning it about every ten seconds until the cake is cooked. The time required for cooking is seven or eight minutes. Condiments, such as pepper, salt, and mustard, may usually be allowed, unless hyperchlorhydria is a prominent feature. If the patient complains much of hunger, a few spoonfuls of beef-tea or a piece of unsweetened chocolate may be given two and EXCLUSIVE PROTEID DIET 555 a half hours after each meal. A cup of clear tea may be given in place of some of the afternoon hot water. The theoretical considerations on which the exclusive proteid diet is based cannot be considered here, and, indeed, they are largely speculative in nature, but some reference to the subject will be made later. Meanwhile it need only be said that the treatment un- doubtedly yields good results in some of the chronic disorders of digestion and nutrition already indicated, but it is only in exceptional cases that it is required, and in any event it is not advisable to continue such a regimen for longer than six weeks at a time. The reader may have noticed that vegetarianism, the purin-free diet, Dr. Hare's system, and, to some extent, the ' exclusive proteid diet ' are all recommended by their supporters in very much the same class of disorders, and it may seem strange that systems so opposed should be capable of curing identical diseases. In these circumstances one naturally looks for some peculiarity common to all the systems which might explain this apparent contradiction. I would venture to suggest that this may be found in the fact that they all tend to promote a more complete oxidation of the proteids. Such a result may be brought about either by lessening the total intake of proteid or by diminishing the proteid sparers (especially the carbohydrates) which interfere with their complete combustion. Now, in vegetarianism, as we have seen, the total amount of proteid in the diet is apt to be low, and the same is true, in practice, if not in theory, in the case of the purin-free diet ; in Dr. Hare's system, on the other hand, and still more in the case of the exclusive proteid diet, the proteid sparers are greatly reduced. Whichever of these plans is adopted then, it is probable that the oxidation of the proteid of the food is likely to be more complete than is the case with an ordinary abundant mixed diet. It will be remembered that one of the advantages claimed for the Chittenden diet standard is that it tends to promote this complete utilization of proteids, and it is note- worthy that the advocates of Chittenden's plan claim that it also is capable of preventing or curing much the same class of diseases as those for which the systems of diet dealt with above are recom- mended. It is possible, too, that any marked alteration in diet is capable of effecting an improvement in general health, just as change of air does, and in ways that are as ill understood. 556 FOOD AND DIETETICS ZOMOTHERAPY. 1 By the term ' zomotherapy ' (Zu>fws, meat-juice) is meant treatment by raw meat or raw meat-juice. It was first introduced by Professor Charles Richet in igoo, 2 and was based on the successful results obtained by feeding dogs which had been inoculated with tuberculosis on raw meat, although Fuster had recommended a diet of raw meat and alcohol in tuberculosis as far back as 1865. Subsequent experi- ments showed that the beneficial properties of raw meat reside in the muscle-juice and not in the fibres, and, further, that the benefit derived is not to be ascribed to hyper-alimentation, inasmuch as (in dogs) a daily dose of 50 to 100 c.c. of the juice are sufficient to give the desired results. The modus operandi of raw meat-juice in the cure of tuberculosis is not understood, but it has been suggested either that it contains a specific ' tonic ' and stimulant, or that it acts in virtue of the presence of some antitoxic substance. Zomotherapy is indicated in cases of anaemia, neurasthenia, debility, convalescence, and latent, incipient, or active tuberculosis. In carrying it out the juice should either be obtained fresh by expres- sion 3 from the best rumpsteak or Carnine Lefrancq (p. 101) may be used instead. The fresh raw juice may be given in quantities of 3 ounces a day and upwards, preferably in tepid beef-tea. The dose of Carnine Lefrancq is from 1 to 6 tablespoonfuls daily, given alone or mixed with any other liquid (except beef-tea), either cold or slightly warm. Salt-Free Diet. The average amount of common salt in an ordinary diet is about 17 grammes per day, and although it is impossible, even were it desirable, to construct a genuinely ' salt- free ' diet, yet by a judicious selection of foods it is easy to reduce the daily intake to about 2 grammes. Such a limitation of salt is of use in the treatment of dropsy, particularly the dropsy of chronic parenchymatous nephritis. It was shown by Widal — to whom much of the credit of introducing the salt-free diet is due — that a chronically inflamed kidney is 1 See Hericourt, 'Zomotherapy.' Paris: J. Rueff. a Comptes Rendus de I'Acadimie, 1900, cxxx. 605. 8 The ' Hercules ' Meat-juice Press gives the best yield. It can be obtained from Messrs. Shoolbred, Whiteley, or Kent (High Holborn). Philip (' Zomo- therapy in Pulmonary Tuberculosis,' The Practitioner, 1905, lxxiv. 141 also exhibits zomotherapy in the form of ' raw-meat soup ' prepared as follows : Take J pound of finely- minced fresh meat, and mix in a bowl with sufficient milk to produce a thick, uniform paste. Immediately before serving add J pint of milk at 150 F. In place of milk, the soup may be made in similar fashion with stock of beef, or chicken, or veal. SALT-FREE DIET 557 Incapable of excreting common salt freely. The salt is therefore retained in the body, and in order that the normal composition of the body fluids may be maintained water is kept back also, with the result that dropsy sets in. When the amount of salt in the food is reduced the percentage of it in the blood gradually falls, the salt which has been stored up in the dropsical effusion is drawn upon to make good the deficiency in the blood, and with its withdrawal the dropsy subsides. Such, put briefly, is the rationale of the plan and of its success in cases of chronic parenchymatous nephritis, 1 and also, though less conspicuously, in cardiac dropsy, 2 and in the ascites of cirrhosis 3 there can no longer be any doubt. A comparatively salt-free diet is not difficult to construct. It must, of course, contain no added salt. Ordinary bread, salt butter, sea-water fish, dried, smoked, salted and preserved foods and sauces and pickles must be avoided. Soups should be made from vegetables and milk. Bread must be baked without salt, or its place taken by home-made scones. The following table, which shows the amount of salt per 1,000 parts in some common articles of food, will be of assistance in making a selection : 8-IO o-6 5 '4 Meat .. -3-1-0 1 -5-2-5 Potatoes 05 1-6 Fresh-water fish 0-48 23 Fruit I'd Rice 002 Bread Sea- fish . Milk Eggs, Lentils Fresh butter The following may be regarded as a typical bill of fare : 4 Breakfast : An egg, bread without salt, fresh butter, tea or coffee and cream. 10 a.m. : A glass of milk. Dinner : Chicken or fresh-water fish ; potato ; jelly. 3 p.m. : A glass of milk. Supper : An egg, chicken, or fresh-water fish ; bread without salt ; custard ; fresh butter. 8 p.m. ; A glass of milk or water. Sour Milk Treatment. 5 Curdled milk has long entered largely into the diet of the inhabit- ants of many countries in the Near East — e.g., Turkey, Roumania, Bulgaria, and Servia — the best-known preparation being the Bulgarian 1 Fowler, Med. Press, October 13, 1908. 2 Mendel, Munch. Med. Woch., 1909, lvi. 433, 516. 3 Vasoin, Archivf. Verdauungs. K., 1905, xi. 633 (abstract). 4 Peabody, Med. Record, 1907, lxxi. 381. 6 For further details see Herschell, ' Soured Milk and Pure Cultures of Lactic Acid Bacilli in the Treatment of Disease ' (Glaisher, 2nd edition, 1909), and 'Lactic Acid Bacilli Preparations' (W. Martindale, 10, New Cavendish Street, W.). 558 FOOD AND DIETETICS yaghourt, or yohourth, in which the souring is brought about by the Bacterium Caucasicum, or Bulgarian bacillus. Metchnikoff 1 sug- gested the use of this preparation in the treatment of disease, and Cohendy 2 first proved the possibility of acclimatizing the Bulgarian bacillus in the intestine, and of lessening intestinal putrefaction by so doing. The Bulgarian bacillus has the advantage over other lactic-acid producing organisms for this purpose, in that it is both more resistant and more active. Since its introduction this method of treatment has attained a wide popularity, and soured milk is now being largely used, either in a ready-made or home-made form. It must be pointed out, however, that many commercial preparations of soured milk either do not contain the Bulgarian bacillus at all, or contain it in a very impure form, and the same is true of the many tablets or liquid cultures which are sold for preparing it at home, and which are designed for the direct inoculation of the intestine. 8 That some of the impurities which these preparations contain may produce harmful results there can be no doubt, and it is therefore advisable that the soured milk should always be prepared at home, and from cultures of guaranteed purity. The time has not yet come for a final pronouncement on the value of soured milk as a therapeutic agent, but it has been recommended in cases of chronic ill-health without obvious cause, in neurasthenia and intestinal affections — e.g., colitis, fermentative diarrhoea, con- stipation — besides gout, arterial sclerosis, and some skin diseases. As regards many of these affections it may be pointed out that there is little or no proof that they are the result of intestinal putrefaction at all, and any improvement which soured milk may produce in them is probably to be ascribed to the fact that it provides an easily-digested form of food, and so improves the patient's nutrition. 4 On the whole there can be little doubt that the treatment has been much overdone, and that in consequence it will before long fall into perhaps unmerited disrepute. In cases of hyperchlorhydria and chronic acid gastritis it is always contraindicated. 1 'The Prolongation of Life.' 2 Comptes Rendus de laSoc. de Biol., 1906, lx. 558, 602, 872. 8 See report of a discussion on 'The Lactic Acid Treatment,' Proc. Roy. Soc. of Med., January, 1910. * See Rosenberg, Arckiv f. Verdauungsk., 1909, xv. 458. [ 559 ] CHAPTER XXX ARTIFICIAL AND PEEDIGESTED FOODS AND ARTIFICIAL FEEDING In this chapter we shall describe some patent and artificial foods not yet dealt with, and consider the methods of administering food otherwise than by the mouth. i. Artificial Foods. 1 The objects of artificial foods may be said to be either (i) to present a maximum of nourishment in a minimum of bulk, or (2) to enable one easily to enrich the diet in respect of certain of its chemical constituents. In regard to the former of these objects, it is well to realize at the outset what degree of concentration of food is chemically possible. Let us take first the case of the proteids. Lean meat may be regarded as the type of a natural proteid food. It contains about one-fifth of its weight of that constituent, the rest being chiefly made up of water. If one drives off all the water from 5 ounces of meat, there will be left behind about an ounce of what is practically pure proteid. Now, this may be regarded as the maximum degree of concentration of which proteid food is capable. In other words, an ounce of any artificial proteid food can never represent more than 5 ounces of lean meat. A more concentrated proteid food than that is a chemical impossibility. One can realize from this the absurdity of such preparations as beef-lozenges. Even did these consist of pure proteid (which they never do), it would require 1 ounce of them at least to be equal in food value to 5 ounces of fresh meat, so that the amount of nutriment contained in one lozenge must be very small indeed. 1 For an exhaustive account of artificial foods see ' Die Kunstlichen Nahrpra- parate und Anregiingsmittel,' by Dr. Max Heim (Berlin, 1901). See also Julian Marcuse, ' Kritische Uebersicht ueber die diatetischen Nahrpraparate der Neuzeit,' Therap. Monatshefte, 1900, xiv. 257. 560 FOOD AND DIETETICS Or take, again, the case of the carbohydrates. There is no form of carbohydrate food more concentrated than sugar. Any fluid or semi-fluid carbohydrate preparation must inevitably be of lower nutritive value than sugar, for it contains more or less water, the food value of which is nil. Such preparations as malt-extracts, therefore, can never add to the diet as much carbohydrate as an equal weight of ordinary sugar. The same is true of fats. No artificial preparation can have a higher food value than pure olive-oil, which contains no water, or dripping, from which all the water has been driven off by heat. . Even ordinary butter contains four-fifths of its weight of pure fat. There are, then, distinct limits beyond which the concentration of foods cannot be carried, and the idea that ' food tabloids ' might be prepared, one or two of which would be the equivalent of an ordinary meal, is seen to be an impossible dream. At the most, all that the maker of concentrated artificial foods can hope to do is to drive off from the natural food the excess of water which it contains, and even then most, if not all, of the original water must be returned to the food before it can be eaten. It may be questioned, too, whether the use of highly concentrated foods is physiologically defensible. The digestive organs are not constructed for the disposal of foods in an extremely compact form. Such forms of nutriment make large demands upon the secretory powers of the stomach, and are apt to be irritating to the digestive organs, in addition to which the total absence in them of ' ballast ' renders them unable to supply an adequate stimulus to the peri- staltic movements of the intestines. As exclusive foods, therefore, such preparations are eminently unsuitable. The second object of these substances, that of enabling one to enrich the diet in certain ingredients, is more legitimate. Here the artificial food is used simply as an accessory to supplement the lack of proteid, carbohydrate, or fat in other articles of diet. Their small bulk is here a decided advantage, for it enables them to be added to fluid foods without appreciably increasing the total amount of material to be swallowed, and in many cases of illness this is a desirable thing to do. One may conclude, then, that concentrated foods are only to be used as accessories, and that they have no legitimate place in the dietary of health. In cases of sickness, however, they have a definite but limited sphere of action. In these circumstances, when appetite is in abey- ARTIFICIAL FOODS 561 ance, it is often a question not so much of getting the patient to take much nourishment as of persuading him to eat at all. It is then that the artificial foods serve a useful purpose, for they can be varied to suit the caprices of the patient, and though the amount of actual nourishment which they yield may be small, they may yet kindle a desire for ordinary foods. The value of any artificial preparation in such a case is not to be estimated by the amount of energy it yields, so much as by its aesthetic qualities and the degree to which it pleases the patient. Suggestion, in fact, plays a large part in bringing about whatever good results artificial foods are capable of producing. Artificial Proteid Foods. 1. Undigested — {a) Of Animal Origin. — Probably the best of the undigested proteid foods are now derived from casein, the chief proteid of milk. In a previous chapter (p. 143) most of these have been described (Plasmon, Casumen, Protene flour, Sanatogen, etc.). They have the advantage of being colourless, tasteless, and readily soluble, so that they can easily be added to other foods, besides which they are digested without difficulty and are very completely absorbed. Of the artificial proteid foods derived from meat, most belong to the predigested class to be considered immediately. Such a preparation of dried meat as pemmican, however, may fairly be regarded as belonging to this group, and the same may be said of the dried meat prepared by the Gye and other processes (see p. 165). As has been pointed out elsewhere (p. 108), anyone can, with a "little trouble, prepare for himself a powder of dried meat, the nutritive value of which is as high as that of any artificial preparation. (b) Of Vegetable Origin. — The chief vegetable proteid foods are Aleuronat, Legumin, Eoborat, Glidine, and Plantose. The first is a special preparation of gluten containing 80 to 90 per cent, of proteid. It is a yellowish-brown powder, almost insoluble in water, and can be conveniently used as an addition to semi-solid foods. It is largely employed, also, in the feeding of diabetics, and has the advantage of being fairly cheap. Legumin (vegetable casein) is the chief proteid of pulses, and is a valuable and highly nutritive substance, apt, however, to have a rather bitter taste, 36 562 FOOD AND DIETETICS Plantose 1 is a very similar vegetable proteid obtained from rape seed. Roborat and Glidine have been described already (p. 220). Tropon 2 is a proteid food derived both from animal and vegetable sources, but chiefly from fish and cheap vegetables. It was first prepared by Dr. Finkler of Bonn. It is a brownish powder, free from taste and insoluble in water, but can be easily given if stirred up in thick soups, pur6es, etc. Three-quarters of an ounce of it contain as much proteid as 4 ounces of beef. It costs 4s. per pound. A very cheap form of pure vegetable proteid has recently been prepared from castor seeds, and will probably prove of great nutritive value. 3 2. Digested Proteid Foods, or 'Peptone Preparations.' — Before describing the members of this group in detail, one or two pre- liminary questions must be considered. And first it may be asked, Are peptones of as much value in the diet as proteids? Are they equally well assimilated and as capable of repairing tissue waste ? At one time some doubt existed about these questions, but now one may say with confidence that peptones are fully capable of playing the part in nutrition ordinarily taken by proteids, provided they be given by the mouth. 4 If injected directly into the circula- tion, it is true that they are not assimilated, but if taken in the ordinary way they are converted into natural proteids before entering the blood. It has also been objected that the substitution of peptones for ordinary proteids in the diet must tend to demoralize the stomach by doing some of its work for it, and so render it incapable, through want of practice, of performing its usual digestive functions. This objection seems to be a hypothetical rather than a practical one, and with the exception of one experiment by Roberts, 5 on which he did not himself lay much weight, there is little evidence in support of it. Further, it must be remembered that peptones are not intended for the healthy, but for those in whom the stomach is presumably 1 Bell and Neumann, 3, Mincing Lane, E.C. 2 Supplied by Arthur Reiner and Co. , Dashwood House, Old Broad Street, E.C. 8 Prepared by Mr. Geo. Mitchell, 39, Victoria Street, S.W. 4 See especially Hildebrandt, Zeit. f. Physiolog. Chem., 1893, xviii. 180; Neu- meister, Deut. Med. Woch., 1893, xix. 866, and Von Noorden, Tkerap. Monalsln/t, 1892, vi. 271. 6 ' Digestion and Diet,' p. 209. ARTIFICIAL PROTEID FOODS 563 already incapable of doing its work, and in such a case the administration of peptones, by improving general nutrition, might be expected to strengthen rather than to enfeeble the digestive powers. A much more real disadvantage attending the use of peptone preparations is their tendency to produce diarrhoea, for when intro- duced suddenly and in large amounts into the stomach and intestine, they seem to induce a large flow of water into the alimentary canal from the blood, and this is accompanied by an increased activity of peristalsis. For this reason they must always be used cautiously and in moderate quantity, while in conditions of diarrhoea the more concentrated forms should be avoided altogether. It may be questioned, too, whether the cases in which peptones are really required are at all numerous, for an inability on the part of the stomach to digest ordinary pfoteids properly presented to it, and in a state of fine division, must be regarded as of very rare occurrence. On the other hand, peptone preparations appear to have the power of exciting a secretion of gastric juice, and of promoting appetite in much the same way as the extractives of meat. Their nutritive value, therefore, is indirect rather than direct, and is to be measured more by their general effect upon the well- being of the patient than by the amount of energy which they supply. 1 Of solid peptone preparations Somatose 2 is the best example. Strictly speaking, it consists of albumoses rather than of genuine peptone, but the same is true of the majority of the so-called peptone preparations, and for dietetic purposes albumoses and peptones may be regarded as identical. Somatose is prepared from meat, and occurs as a grayish powder, readily soluble in water and practically devoid of taste or odour. The following is an analysis of it by Tankard : 3 Water . . . . . . . . 1425 per cent. Alkali albumin .. .. ..2183 „ Coagulable albumin .. .. 340 Albumoses.. .. .. .. 3396 „ Peptones .. .. .. .. 306 „ Meat bases.. .. .. .. 262 ,, Ash 530 „ 1 See a paper by F. Voit, ' Ueber den Werth der Albumosen und Peptone fur die Ernahrung ' (Munch. Med. Wochensch., 1899, xlvi. 172) ; also Max Voit, Zeit. f. Biologie, 1903, xlv., N.F. , xxvii. 79. a Supplied by the British Somatose Co., 165, Queen Victoria Street, E.C. 3 Allen's ' Commercial Organic Analysis,' iv. 384. 36—2 5 6 4 FOOD AND DIETETICS Roughly speaking, it may be said to contain from 60 to 70 per cent, of building material, and a teaspoonful of it is equal in this respect to about £ ounce of lean meat. It can be easily added to fluid or semi-fluid foods, but if largely used may produce diarrhoea. 1 The dose recommended is about three or four teaspoonfuls daily, and it seems to be very well absorbed. 2 Like most of the preparations we are now considering, Somatose is rather expensive, an ounce of it costing is. 8d., and yielding for that sum only as much nutriment as \ pound of beef. Milk Somatose is a similar preparation obtained from the proteids of milk. It contains 5 per cent, of tannic acid in combination. Carnrick's Peptonoids is another solid preparation containing predigested proteids.' The following is Tankard's analysis of it : 3 Water .. .. .. .. 213 per cent. Insoluble proteids .. .. 1222 Albumpses.. .. .. .. 3-17 Peptones . . . . . . . . 088 Meat bases .. .. .. 287 Starch .. .. .. .. 2364 Milk-sugar 4852 Fat .. .. .. .. .. 200 Ash 457 It will be observed that the substance owes its nutritive value to carbohydrates rather than to proteids, and that the larger part of the latter is present in an insoluble form. The following tables contain analyses of some of the semi-solid and liquid peptone preparations : 1 See Bornstein, Berlin. Klin. Woch., No. 8, 1897. 8 For literature relating to Somatose and its uses, see Hildebrandt, Verhand. »?. I2tot Cong. f. Inn. Med., 1893, 395 ; also references in Edin. Med. Journ., February, 1899, and the British Physician, July 15, 1899 ; also a paper by Steven- son and Luff, Lancet, September 30, 1899. The conclusions of the two latter writers are as follows : i. Somatose is a true meat nutrient possessing restorative and stimulating powers, ii. It is well borne by delicate patients. iii. It improves digestion and causes no gastro-intestinal disturbances. iv. It has a favourable effect on general metabolism, v. It never gives rise to the appearance of albumin, albumose, or peptone in the urine. s Allen, he. cit. COMPOSITION OP PEPTONE PREPARATIONS 5^5 COMPOSITION OF PEPTONE PREPARATIONS (CHIEFLY FROM ANALYSES BY THE AUTHOR). Preparation. Water. Soluble Proteids (chiefly Albumoses). Extractives and other Non proteid Organic Matter. Mineral Matter. Koch's Peptone Liebig's Peptone 1 Brand's Beef Peptone 40-16 319 846 3478 33 40 70 I5-93 24-6 689 99 i'4 Denaeyer's Peptone' Darby's Fluid Meat 3 Armour's Wine of Peptone 7845 2571 830 I2'I5 3060 30 432 30l8 129 254 1350 i-i Fairchild's Panopepton . . Peptonized Milk 4 .. 8i-o 87-5 30 I 76 I50 (largely sugar) 1004 (=sugar, fat, and unaltered proteid) I/O 07 1 Leyden's ' Handbuch der Ernahrungstherapie.' 3 Ibid. ; see also Von Noorden, Tkerap. Monatsheft, June, 1892. * Horton Smith, Journ. of Physiolog., xii. 42, 1891, and Leyden's 'Handbuch.' * Horton Smith, loc. cit. COMPOSITION OF SOME PEPTONE PREPARATIONS (KONIG). Other Preparation. Water. Total Nitro- gen. In- soluble Proteid. Albu- moses. Pep- tones. Nitro- genous Com- pounds. Fat. Ash. Antweiler's Peptone 692 1285 3'22 1454 6015 I20 054 I3\3I Kemmerich's Meat Pep- tone (dry) . . 3330 978 I-IO I4S6 3257 997 0-30 7-73 Koch's Meat Peptone (dry) 4016 780 1-42 15 95 1883 1596 079 689 Darby's Fluid Meat 2571 806 — — 3060 — — I350 Valen tine's Meat-juice . . 5907 2-50 181 487 2273 — 1152 Savory and Moore's Fluid Beef 27-01 8-77 542 274 5273 — 1210 Benger's Pep- tonized Beef Jelly 8968 i'55 — 241 475 227 — 089 Most of these contain so much water that their nutritive value is com- paratively small, while those in which alcohol is present are open to the same objections as other dietetic or medicinal wines 1 (see p. 388). 1 Analyses by Harrington (Boston Med. and Surg. Journ., 1902, clxviii. 283) have shown for example that • liquid peptonoids ' contain 23 per cent, of alcohol by volume, and that the maximum dose for an adult per day would yield as much intoxicant as is contained in 3 \ ounces of whisky. ' Panopepton ' contains 18-95 per cent, of alcohol by volume. 566 FOOD AND DIETETICS Home-made peptonized foods, prepared by aid of such agents as liquor pancreaticus or ' zymine,' are now so well known and widely employed that a special description of them is unnecessary. 1 Peptonized milk is that most commonly used. An analysis of it will be found in the foregoing table. Condensed peptonized milk is sold in tins by Messrs. Savory and Moore. Gruels of various sorts can be prepared in a similar way, peptonized milk gruel being one of the best. Such home-made preparations are mostly to be preferred to commercial articles, and have also the advantage of being very much cheaper. Artificial Carbohydrate Foods. Many patent foods which might justly be included in this section have been already dealt with under the cereals, pulses, etc. The only group which remains to be considered is that of the malt-extracts. These are prepared by evaporating down an infusion of malted barley at low temperatures or in vacuo. The object of evaporating them in that way is to preserve in an active form the diastasic ferment present in the malt ; and the special apparatus required for this purpose is one cause of the expense of such preparations. The following table contains the results of the analyses of some standard malt-extracts: 2 COMPOSITION OF MALT-EXTRACTS. Total Solids. Reducing Sugars. 3 Proteid. Dex- trin. Ash. Alcohol. Diastasic Power. Kepler Extract of Malt . . 78-4 677 5'66 7'4 1-5 — 380 Trommer's Extract of Malt 73'6 559 4°5 8-3 11 — 23 Allen and Hanbury's Ex- tract of Malt 79° ■ 652 4'55 134 I "2 — 39 D.C.L. Malt-Extract 7«' 3 709 625 IO'O l'4 — 366 Cream of Malt 7.V« 608 555 138 1-8 • — 86 Maltine 67-3 61/9 5 '25 5'° I'2 — 940 Standard Malt-Extract . . 76-6 70*0 5'3 122 I- 4 — 382 Bynin 529 51-6 33 3'i 09 8'3 38 Standard Liquid Malt- Ex tract 537 516 5'5 23 i'i 5"o 866 Hoff's Malt-Extract 78 2-5 04 2-3 02 3 - i The average composition of these substances given by Klemperer 4 is as follows : Sugar Soluble starch . . 50 to 55 per cent. 10 ,, 15 Proteids Ash.. 5 to 6 per cent. 1 .1 2 „ 1 For details, see Roberts' ' Digestion and Diet, ' 2nd edit., p. 192. Full direc- tions for preparing peptonized foods are supplied along with the agents mentioned in the text. 2 Brit. Med. Joum. , 1909, ii. 1477. 3 Calculated as maltose. 4 Leyden's ' Handbuch der Ernahrungstherapie.' ' MALT EXTRACTS 567. A large dessertspoonful of such an extract weighs about 20 grms. and has a fuel value of 60 Calories, or about as much as an egg. In the above analyses the whole of the nitrogenous matter has been counted as proteid, but it is very doubtful if that is quite accurate. Some of the nitrogen is almost certainly present in other forms. Desiccated malt extracts 1 from which all the water has been removed are also prepared. They are of high nutritive value and active diastasic power, and are in many respects more convenient than the ordinary extracts. Hoff's Malt Extract, on the other hand, is a liquid preparation. Maltova is a combination of malt-extract and eggs. Malt-extracts may be prescribed with one of two objects : (1) To enrich the supply of carbohydrates in the diet ; (2) to aid the digestion of starchy foods by means of the diastase which the extract contains. The advantages possessed by malt-extracts for accomplishing the former of these objects are not quite apparent. Treacle and golden syrup both contain a considerably higher percentage of sugar, and are vastly cheaper. It is true that malt-sugar is less apt to irritate the stomach than the cane-sugar which treacle and syrup contain ; and although not capable of direct absorption as such, maltose may yet be regarded as a partially digested form of carbohydrate. But in both these respects we have in ordinary honey a superior food. Honey has the following composition : Water . . . . . . . . 16 to 13 per cent. Invert sugar . . . . . . 78 , , 74 , , Cane-sugar .. .. .. 2 '69 ,, Proteid . . . . . . . . 1 '29 , , Ash 0-12 ,, That is to say, it is actually richer in sugar than malt-extract ; and a dessertspoonful has a fuel value of 75 instead of 60 Calories. Furthermore, the sugar of honey is really in a predigested form, and ready for immediate assimilation. As a source of carbohydrate, therefore, honey is in every way preferable to malt-extracts, besides being a good deal cheaper ; 2 and it may be used with great advantage in every case in which one wishes to supplement the supply of carbo- hydrates in the diet. 1 E.g., Curtis' Desiccated Malt-Extract (Curtis and Co., 48, Baker Street, W.) ; 'Gramalt ' (Thomas Christy and Co. , Old Swan Lane, Upper Thames Street, E. C. ), and Dr. Wander's Dry (Crystalline) Extract of Malt. For results obtained from the use of desiccated malt-extract see 'Powdered Malt-Extract as a Nutrient,' by Dr. Hingston Fox (Brit. Med. Journ., 1902, i. 835). 8 Malt-extracts cost about 3s. the pound, honey costs about gd. 568 FOOD AND DIETETICS The second property of malt-extracts — that of acting upon starch by means of the diastase which they contain — is but rarely present to the mind of the prescriber. The cases in which such an action is desired are not, indeed, at all numerous, and are practically confined . to the group of so-called amylaceous dyspepsias. Even in such a case malt-extract is not the best preparation to employ. No matter how carefully the extract may be prepared, it always seems to lose something of its diastasic power in the process (Roberts) ; and it is far more certain, as well as cheaper, and one may add pleasanter, to make an infusion of malt at home, and either use it as a beverage at meals, or, preferably, stir it into starchy foods, such as puddings or gruel, before they are eaten. 1 The value of milk-sugar as a means of supplementing the carbo- hydrates of the diet must not be forgotten. Its comparative freedom from sweetness makes it specially suitable for such a purpose. If £ ounce of it is dissolved in 5 or 6 ounces of milk, the nutritive value of the latter is increased by nearly 60 Calories. This may often be taken advantage of in feeding patients with acute fevers. Artificial Fatty Foods. In most cases these consist of some kind of fat presented in the form of an emulsion, cod-liver oil being the special variety of fat usually employed. The object of emulsification is to render the fat more palatable, and also to aid its digestion. The former object is undoubtedly attained ; the achievement of the latter is not so certain. It must be remembered that what is now known of the digestion and absorption of fat makes it certain that the process is mainly a chemical one, and not a mere physical absorption of the fat in the form of fine particles. Hence, though emulsification may be a useful preliminary to digestion, fat so presented cannot be regarded as ready for immediate reception into the blood. Like the malt-extracts, therefore, fat emulsions are only partially predigested foods. The emulsifying agent in these preparations is either an alkaline solution, mucilage, glycerine, or malt-extract. Of these, the three last are to be preferred, for they are unaffected by the acidity of the gastric juice, which is apt to destroy an alkaline emulsion. 1 Roberts recommends an infusion made by soaking 3 piled tablespoonfuls of crushed malt in J pint of cold water overnight, and straining through muslin till clear. It may be preserved in a tightly-corked bottle with the addition of a few drops of chloroform (' Digestion and Diet,' p. 230, where detailed directions for the use of such an infusion are given). FAT EMULSIONS 5^9 An ordinary cod-liver oil emulsion contains about half its weight of fat, and has a fuel value about double that of an equal quantity of malt-extract. The question whether cod-liver oil has any specific virtues other than those of an easily-digested fat cannot be discussed here ; but in the case of the purified oils, at any rate, any such specific qualities can hardly be present, unless they be due to cholesterin, the food value of which, however, is very questionable. A preparation called Lipanin has been largely used in Germany as a substitute for cod-liver oil. It consists of ordinary olive oil con- taining 6 per cent, of oleic acid. The presence of the latter is supposed to facilitate emulsification and absorption in the intestine ; but experiment has not shown that Lipanin is better absorbed than ordinary forms of fat. 1 Miol is a combination of emulsified olive oil with malt-extract, and contains, in addition, iodine, phosphorus, and other ingredients. It is designed to replace cod-liver oil, and contains 22 per cent, of fat and 41 per cent, of reducing sugar. Virol is another cod-liver oil substitute. It is prepared from bone marrow, the yolk of eggs, and malt-extract flavoured with lemon- juice, and has approximately the following composition : 2 Water .. .. 2i'i per cent. Fat.. .. .. 12-3 ,, Carbohydrates .. 59 - o ,, Proteid . . . . 2 p 8 per cent. Ash.. .. .. 1 "6 ,, It is an agreeable preparation of very considerable nutritive value. Cremalto is a combination of Devonshire cream and malt which has the following composition : 2 Proteid .. .. 4 - i per cent. Ash.. .. .. 1 - 3 „ Water .. .. 267 per cent. Fat 117 Carbohydrates .. 563 ,, It also is a pleasant and nourishing preparation. Pancreatic Emulsion is another substitute for cod-liver oil. It is made by pounding up lard with pig's pancreas, with the addition of water, straining, and exhausting the strained substance with ether. The ether is distilled off, and the residue of fat is mixed with rectified spirit and water, and emulsified by agitation. Oil of cloves is added to give flavour and aid preservation. It is not difficult to take, but is no richer in fat than ordinary butter, and considerably more expensive. Spermaceti used to be largely employed as a means of giving fat, 1 See Leyden's ' Handbuch der Ernahrungstherapie,' p. 302. 2 Analysis in Brit. Mid. Journ., 1910, i. 29. 57° FOOD AND DIETETICS but has now dropped out of use. It was given in the form of a powder mixed with sugar, and f ounce could be taken daily- 1 ^ IS well borne and not difficult to absorb. The objection to all these artificial preparations is their expense, and for that reason, if for none other, the use of natural fats is preferable. 2 Of these, cream and butter are the most suitable, for there are but few persons who are unable to digest milk-fat. Ordinary cream, obtained by skimming, contains about 20 per cent, of fat, and three spoonfuls of it are more than equal in fuel value to one spoonful of cod-liver oil emulsion. Butter has 80 per cent, of fat, and can be taken in large quantities if well mixed with starchy foods such as mashed potato. Almonds are also a rich source of fat, of which they, contain more than half their weight. Chocolate, too, has 20 per cent, of fat and 50 per cent, of sugar in addition. Lastly, one should not forget the value of toffee as a concentrated form of fat and carbohydrate in about equal proportion. It has the further advantage that much of the sugar which it contains is in the easily digested ' invert ' form. It may be specially recommended in the case of children who are unable to take cod-liver oil or other forms of fat, and if given only at the end of meals is not likely to do any harm. If the merits of some of these natural forms of fat were rightly appreciated, there would be but little need to have recourse to artificial preparations. 2. Artificial Feeding. 3 Rectal Feeding and Nutrient Enemata. Rectal feeding has constituted a therapeutic resource ever since medical science existed, 4 but it is only within recent times that the value of this method of administering nourishment has been subjected to careful scientific scrutiny. The absorptive power of the large intestine for proteids has been 1 See Senator, Berlin. Klin. Woch., 1887, xxiv. 213. Q I have recently used an emulsion of cotton-seed oil propared with the addition of 6 per cent, of oleic acid as a substitute for cod-liver oil with quite satisfactory results. Pilchard oil may be used in a similar way. Both of these have the advantage of being much cheaper than cod-liver oil. 3 For a critical review of the whole subject of artificial feeding, see an article entitled ' Extrabuccal Feeding,' by C. A. Ewald, Med. Record, igoo, lviii. 24I , 4 For a sketch of the history of the subject, see the valuable monograph by Dr. A. P. Gros, ' Traitement de certaines Maladies de l'Estomac p ar la Curs de Repos absolu,' etc. ; Paris, 1898. RECTAL FEEDING 571 investigated by Eichhorst, 1 Leube, 2 Brandenburg, 3 Huber, 4 Ewald, 5 Plantenga, 6 and others. Their results show that : (1) Peptone is well absorbed ; (2) eggs given alone are not well absorbed, but if 15 grains of salt are added to each egg they are almost as well utilized as if they had been peptonized ; (3) raw -beef juice is very completely absorbed ; (4) albuminoids such as gelatin are not absorbed. The results obtained with enemata of casein are conflicting. Some of the above observers state that it is not well absorbed, but Eich- horst, and more recently Ehrstrom 7 (who used a soluble casein preparation) maintain that it is well taken up by the rectal mucous membrane. Hoppe 8 also found that Sanatogen is absorbed to the extent of fully 77 per cent., and Goliner 9 that Plasmon dissolved in hot water makes a satisfactory enema. As regards carbohydrates, it has been found that sugars are well absorbed, but are apt in concentrated solution to prove irritating to the mucous membrane. Leube advises that the solution should not be stronger than 10 to 20 per cent., and that not more than 300 c.c. should be given at one time. Even then there is a risk of the enema being very soon returned. Curiously enough, starch seems to be fairly well absorbed, 10 even when given in the raw state : 50 to 100 grammes of it may be given in 300 c.c. of water. It is not at all irritating. Fats are not at all well absorbed when given by the bowel. 11 The total amount absorbed depends on: (1) The absolute quantity ad- ministered ; (2) its length of stay in the bowel ; (3) the temperature of the enema and the presence or absence in it of common salt. Not 1 Archiv. f. Physiolog,, 1871, iv. 570. 2 Leyden's ' Handbuch der Ernahrungstherapie,' p. 496 et seq, 3 Deut. Archiv. f. Klin. Med., i8g6, lviii. 71. 4 Ibid., 1 89 1, xlvii. 495. 6 Archiv. f. Anat. und Physiolog, , 1899, Supp. Bd., p. 160. 6 Centralbl. f. Physiolog., 1899, xii. 734, (abstract of dissertation) ; see also Gros, op. at. 7 ' Ueber den Nahrwerth der Casein Klystiere,' Zeit. f. Klin. Med., 1903, xlix. 377- 8 Munch. Med. Wockensch., 1904, li. 2294. 9 Zeil. f. Phys. und Diat. Therapie, February, 1907. 10 This statement is not quite borne out by the recent observations of Reach (' Ueber Resorption von Kohlehydraten von der Schleimhaut des Rektums,' Zeit. f. Dibit, und Physik. Therapie, 1903, vii. 229). He administered enemata of 60 grammes of sugar or dextrin in 120 to 200 c.c. of water, and of 100 grammes of starch in 300 c.c. of water, using the respiratory quotient as the test of absorp- tion. He concludes that some sugar is absorbed, but very little starch* He is inclined to recommend the use of dextrin, for it is as well absorbed as sugar, and less irritating to the mucous membrane. O. Griinbaum has found that 30 grammes of sugar can be absorbed without the production of glycosuria. 11 See Deucher, Deut. Archiv. f. Klin. Med., 1897, lviii. 210. 572 FOOD AND DIETETICS more than 25 grammes of fat should be given at once, and with at least as much water. The enema should be give at the body temperature, and enough salt added to form a normal saline solu- tion. The bowel should be empty, and only one enema given daily. Even under these favourable conditions, not more than 10 grammes of fat are likely to be absorbed daily. It follows from these experimental results that the best ingredients for nutrient enemata are: (1) Peptones, albumoses, and powdered casein preparations ; (2) eggs, with the addition of salt ; (3) raw- beef juice; (4) dilute solutions of grape-sugar or dextrin; (5) and perhaps unboiled starch. To this list should be added alcohol, which is perhaps better absorbed by the large intestine than any- thing else except water. 1 It may be admitted that the capacity of the large intestine to absorb some of these articles is not easy of explanation. It is pretty clearly established that the colon secretes no digestive ferments. How, then, it may be asked, is it capable of absorbing such sub- stances as egg-white and unboiled starch ? There is one easy way out of the difficulty, and that is by assuming the occurrence of a reverse peristalsis, which carries substances injected into the rectum up above the ileo-ca?cal valve into the small intestine. That such a reverse peristalsis is possible is, I think, no longer open to doubt. It is proved by the experiments of Gnitzner, 2 by the observations of Nencki, Macfadyen and Sieber on a patient with a fistula at the lower end of the ileum, 3 and by the incontestable fact of the occa- sional vomiting of enemata by hysterical patients. 4 It is very probable that in this way a part at least of a nutrient enema gets carried into the small intestine, where absorption can readily occur. Variations in the patency of the ileo-caecal valve may explain the different degrees to which different individuals absorb such enemata. Special emphasis must be given to the great extent to which the addition of salt to nutrient enemata promotes their absorption. This is a practical matter of the first importance. Its modus operandi, however, is not easy of explanation. It may perhaps stimulate the appearance of the reverse peristalsis above referred to, or it may excite the intestinal cells to greater absorptive efforts, while it 1 The whole subject of rectal alimentation was reviewed by Sharkey in the Bradshaw Lecture, 1906 (Lancet, 1906, ii. 1263), but his conclusions are in the main in agreement with those expressed in the above paragraph. He gives a very complete bibliography of the subject 2 Pfluger's Archiv., 1898, lxxi. 492. * Archiv. f. Exper. Path, and Pharmah., 1891, xxviii. 311, * Gros, op. lit., chap, iv. NUTRIENT ENEMATA 573 undoubtedly facilitates the diffusion of the enema over the surface of the bowel. Putting aside these rather academical discussions, there is abundant clinical evidence for the feasibility of nourishing patients, for some time at least, by the rectum exclusively. In several cases cited by Gros, patients were fed by this method alone for as long a period as three weeks, and with but little loss of weight. 1 The process, however, cannot be continued indefinitely, for, apart altogether from the fact that the rectum sooner or later becomes intolerant, one can hardly hope, allowing for deficient absorption, to get more than 500 Calories of energy into the blood daily by this means, and that is only about a quarter or at most one-third of the amount required even by patients who are kept very warm and at absolute rest. Much of the value of nutrient enemata, indeed, is almost certainly due to absorption of water, which may explain the cases in which weight is gained. It is only in exceptional cases that one can prevent tissue-loss by their use, and the best that can be hoped for is to prevent the patient losing ground when already in a condition of decided sub-nutrition. 2 It has been proved, also, that the administration of a nutritive enema is followed by the out- pouring of some gastric juice into the stomach, and in cases of gastric ulcer this may be harmful and interfere with healing. Milk is most commonly used as the basis for enemata, as it is simple, convenient and unirritating, in spite of the fact that only about one-third of the casein which it contains is absorbed. The following are some of the formulae for enemata containing milk recommended by Leube : 3 Peptone and Milk Enema. Peptone, 60 grammes. Milk, 250 c.c. Egg and Milk Enema. 3 eggs. 3 grammes of common salt. Milk, 250 c.c. Sugar and Milk Enema. Grape-sugar, 60 grammes. 4 Milk, 250 c.c. Starch and Milk Enema. Starch (unboiled 5 ), 60 to 70 grammes. Milk, 270 c.c. 1 See also Ewald, Archiv. f. Anat. und Physiolog., 1899, Supp. Bd., 160, and Rost Berlin. Klin. Woch., 1899, xxxvi. 660, 686. 3 See Edsall and Miller, Univ. of Pennsyl.-Med. Bull., January, 1903, xv. 414 (abstract in Brit. Med.Journ., Epit., 1903, 83). 3 28 grammes, or 28 c c. = 1 ounce. 4 This would be contained in about 3 ounces of honey. * Boiled starch is too thick to inject. 574 FOOD AND DIETETICS It might be well to peptonize the milk first. Somatose may be used instead of peptone. Red wine is recommended as an addition by many Continental writers. The alcohol which it contains is readily absorbed, while its astringency and slight acidity seem to favour retention of the enema. 1 The following formula? are examples ; Ewald's Enema. 2 tablespoonfuls of wheat flour. 5 ounces of lukewarm water or milk. I or 2 eggs with a pinch of salt. Beat up with 2 to 4 ounces of a 15 per cent, solution of glucose. Then add 1 glass of claret. Boas' Enema. Milk, 9 oz. Yolks of 2 eggs. A pinch of salt. Red wine, J oz. Starch or arrowroot, J oz. Riegel's Enema. Milk, 9 oz. 2 to 3 eggs. 2 to 3 pinches of salt. Red wine, 1 oz. Toumier's Enema. Beef-tea, 2 5 ozs. The yolks of 6 eggs. 2 small spoonfuls of salt Red wine, 1 oz. The eggs should be beaten up for at least five minutes, so as to mix them thoroughly. Boyd and Robertson 3 find that for practical purposes the following is the best formula to use : The yolks of two eggs. 30 grammes pure dextrose. 0-5 gramme common salt. Pancreatized milk to 300 c.c. Given every six hours the amount of nourishment injected would equal 1,200 Calories. Absorption under favourable circumstances might amount to 500 Calories, but would probably be much less. Leube's Pancreas Enema is an _attempt to imitate natural intestinal digestion. It consists of a mixture of chopped pancreas and lean meat, with the addition of some fat, in the following proportions : 1 Bial (Arch. f. Verdauungs, 1903, ix. 433) found that of an enema containing 10 per cent, of peptone 50 per cent, was absorbed, but that by the addition of 10 per cent, alcohol the absorption was raised to 66 per cent. 2 Raw-beef juice would be better. 3 The Scottish Med. and Surg. Journ., March, 1906, xviii. 193. NUTRIENT ENEMATA 575 Pancreas 50 to 100 grammes. Meat .. .. .. .. 150 ,, 300 „ Fat 30 „ 45 The pancreas and meat should both be free from fat, and chopped as finely as possible. They are stirred up in a basin with a large spoon, 150 c.c. of lukewarm water being added. The fat should be mixed with the mass in a mortar very thoroughly by aid of a warm pestle. Leube claims that this enema is unirritating and well retained, and that the fat in it is freely absorbed and can be demonstrated in the cells of the large intestine in the form of droplets. No starch should be added, for sugar is produced from it so rapidly that it irritates the mucous membrane of the bowel. Others, however, have found that this enema results in a great deal of intestinal putrefaction, and even in some degree of toxaemia. 1 O. Griinbaum 2 has used enemata of ox-serum 3 with success, 2 grains of chloretone being added to each ounce of the serum to act both as a sedative and a preservative. Ninety c.c. (3J ounces) may be injected every four hours, which yields 38 grammes of proteid in the day. By the addition of 60 c.c. (about 2 ounces) of milk the total proteid is raised to 51 grammes per day. He has found that such enemata are very well absorbed. General Technique. Enemata should be given at the body temperature, and their bulk should not exceed 250 c.c. (about 9 ounces). Fluids should be given through a soft oesophageal tube of small calibre, introduced as high as possible, and connected with a funnel raised to a height of 3 feet. Thicker mixtures (such as the pancreas enema) should be adminis- tered by means of an ordinary enema or pressure syringe. The enema should be given slowly, and the patient should lie quiet fot an hour after it has been injected. Three or four enemata in the twenty-four hours is a sufficient quantity, and one cleansing injection should be given daily, for absorption is greatly promoted by having the surface of the mucous membrane clean. If the enema is badly retained, a little opium may be added. One must persevere even if the first few injections are returned, and try to find amongst the above formulae one that suits the particular case. 1 See Boyd and Robertson, loc. cit, s Brit. Med. Journ., 1900, ii. 424, and igoi,[xi. 788. 8 Supplied by Parke, Davis and Co. 576 FOOD AND DIETETICS Nutrient suppositories cannot be recommended. They usually contain peptone, but at most not more than 125 grains in each, which means, even assuming complete absorption, an energy value of less than 35 Calories. The absorption of such suppositories has been found in some cases to be very far from perfect. Subcutaneous Feeding. The injection of nutritive substances under the skin may be regarded as the latest method of administering food artificially. It was first introduced by Menzel and Perco in the year 1869, * but has only come into use very slowly since that date. In order that a food may be available for subcutaneous adminis- tration, it must fulfil three conditions : 1 . It must be capable of direct assimilation. 2. It must be unirritating. 3. It must be of such a nature that it can be easily sterilized. There are but few foods which meet all these requirements. Most proteids are unsuitable, because those which can be directly assimilated by the tissues are not easily sterilized without under- going coagulation ; and, on the other hand, those which can be readily sterilized, e.g., peptones and albumoses, are not directly appropriated by the tissues, and even act as poisons to them. 2 A solution of egg white, even supposing it to be assimilated, which some writers deny, is difficult to prepare in a sterile form, and is apparently apt to cause damage to the kidneys. 3 Serum, however, contains proteids in a form in which they can be sterilized without much difficulty, and which are directly assimilable. If serum is heated to 55 C, it becomes opalescent, but does not coagulate, and can then be injected without danger. 4 Reinach 5 brought round children who were very much exhausted by diarrhoea by injecting 20 c.c. of ox serum under the skin at the sides of the thorax. This quantity, however, contains only about i£ grammes of proteid, and it is probable that the injection of salt solution would have an equally favourable effect. 1 For the history of subcutaneous feeding, see Bauer, 'The Dietary of the Sick ' (Von Ziemssen's ' Handbook of General Therapeutics,' vol. i.), p. 271, and Leube in Leyden's ' Handbuch der Ernahrungstherapie, ' i. 513. 2 See Neumeister, Deut. Med. Woch., 1893, xix. 866. 3 See Leigh ('Nutritive Infusions ') New York Med. Journ., 1902, lxxyi. 368; Jackson (' Subcutaneous Injections of White of Egg'), ibid., 1902, lxxvi. 813) ; and Laborde (' De 1' Alimentation Sous-cutanee par les Matieres Albuminoiides '), J. de Physiol, et de Pathol., 1900, ii. 700. 4 Friedenthal and Lewandowsky, Archiv. f. Anat. und Physiolog., 1899, 531. • Berlin. Klin. Woch., March 20, 1899. SUBCUTANEOUS FEEDING 577 Horse serum contains from 7J to 8 per cent, of proteid, 1 and is a more suitable form for administration in this way. Salter 2 has injected as much as 100 to 120 ex., previously heated to 65° C, of it under the skin in adults without any bad effects. No albuminuria appeared, and the total nitrogen excretion in the urine was increased. The total amount of proteid which can be administered by this method, however, can never be of much nutritive importance. Carbohydrates in the form of grape-sugar are easily sterilized, and can be directly assimilated. F. Voit 3 found that as much as 60 grammes of grape-sugar in 10 per cent, solution could be injected under the skin of the thigh without glycosuria resulting. Unfor- tunately, however, sugar solutions are irritating, and much pain and infiltration are apt to be produced at the site of injection. Miiller,* for instance, injected a 10 per cent, solution under the skin of his own thigh, but so much pain was produced that he resolved never to try the experiment again. Leube 5 states that at most 15 to 20 grammes of grape-sugar can be injected without great pain resulting. Barker 6 recommends the injection of a 5 per cent, solution of glucose in normal saline in conditions of exhaustion or collapse before or after operation. A litre of such a solution may be given in the day, 500 c.c. being injected at a time. The injection is made under the skin near the axilla through an ordinary aspirating needle connected with a funnel by 3 feet of rubber tubing. Fat, in the form of oil, is really the only form of food which fulfils all three conditions, and accordingly it is the only food substance which can be injected under the skin with any freedom. The dangers of producing fat embolism would seem to be imaginary. Leube, after a very considerable experience, has never seen it occur. Olive and sesame oils are the best forms to use : 30 to 40 c.c. should be injected with a 10 c.c. syringe at three different places, the injection being performed slowly and without much pressure, and the puncture sealed with collodion. Injection should be performed only once a day, and the groin is perhaps the best site to select. That oil so injected is really assimilated is evidenced by the fact that the excretion of nitrogen is lessened by it, 7 and post-mortem 1 Szontagh and Wellmann, Deut. Med. Woch., 1898, xxiv. 421. 2 Guy's Hospital Reports, 1896, liii. 241. s Munch. Med. Woch., 1896, xliii. 717, and 1897, xliv. 851. * Gumprecht, Verhand. d. Cong. f. Inn. Med., 1898, xvi, 124. B Verhand. d. Cong.f. Inn. Med., 1895, xiii. 418. 6 Brit. Med. Journ., 1902, i. 770. 7 G. Sommer, ' Stoffwechselversuch mit Subcutaner Fettinjection am Men- schen,' Sitzungsber, d. Physih Med. Gesell. zu Witrzburg, 1897, 26. 37 578 FOOD AND DIETETICS also the fat is found to have disappeared from the point of injection. If the oil be properly sterilized, no local irritation is ever produced, and the injections may be continued for as long as four weeks without bad results. 1 Caird 2 reports a case of stricture of the oesophagus in which the patient was going downhill under enemata, and had a subnormal temperature. Four ounces of sterilized olive oil were injected into the gluteal muscles without the production of any local pain or dis- comfort, and with great benefit to the general condition. Krueg also kept a lunatic alive for twenty days without loss of weight by the subcutaneous injection of 15 to 30 c.c. of olive oil daily, 3 and other observers have repeated his experience. 4 There can be no doubt, then, that feeding by means of the sub- cutaneous injection of sterilized oil is a feasible enough proceeding, but it must be remembered that its value is strictly limited. Recent experiments by Winternitz 6 have shown that fat so given is only very slowly absorbed, and that it cannot supply more than 25 Calories to the body per day. In spite, then, of the apparently favourable results reported above the use of fat for subcutaneous feeding must be pronounced almost useless. The subcutaneous administration of yolk of egg has recently been practised by Muggia 6 in cases of malnutrition in infants and as a substitute for lecithin. The injection is prepared by mixing the yolk of a fresh egg with one-third of its weight of normal saline solution. The mixture is stirred with a glass rod in a previously sterilized vessel, and then strained through gauze. The initial dose is 1 c.c, the injections being made in the buttock or lumbar region. There is no local or general reaction provided aseptic precautions are observed. Gentle massage is performed after the injection, The quantity at each injection may be gradually increased up to 10 c.c, but one should not go above that. He states that the general nutrition and condition of the blood are improved more rapidily under this treatment than under lecithin. G. d'Errico, 7 however, has found from his experiments that such injections produce only slight and temporary improvement, whilst the use of larger quantities is apt to cause grave lesions of the kidneys. 1 See Jacob, quoted by Gumprecht, Verhand. d. Cong. /. Inn. Med., 189S, 124. 2 Edin. Med. Journ., September, 1893. s See Lilienfeld, Zeit. f. Diat. und Physik. Therapie, ii. 209. 4 For example, Fornace and Micheli, Rif. Med., July 14 and 15, 1897 (abstract in Brit. Med, Journ., Epit., September 11, 1897). 6 ' Zur Frage der Subcutanen Fetternahrung,' Zeit. f. Klin. Med., 1903, 1. 80. See also Henderson and Crofutt, A mer. Journ. of Physiol., 1905, xiv. 193. 6 Brit, Med. Journ., 1899, i., September 30. 1 Qiomale intemaz. delle Scienze Med., August 31, 1902, GAVAGE AND FORCED FEEDING 579 Gavage and Forced Feeding. Savage was introduced by Debove in the year 1881. 1 The terra was first applied to the method of introducing food into the stomach by means of a tube in cases of obstinate vomiting. Curiously enough, food so introduced is often retained when nourishment swallowed in the usual way is vomited immediately. The meaning of the term has now been extended so as to cover all cases in which food is artificially introduced into the stomach by a tube in excess of the demands of appetite, a proceeding more correctly described as forced feeding. An ordinary soft stomach-tube is employed, and it is only necessary to introduce it into the upper part of the oesophagus ; it need not enter the stomach proper. If the pharynx is very sensitive, it may be previously anaesthetized by cocaine. A mixture consisting of 1 or 2 pints of milk, 3 beaten-up eggs, and 3 ounces of milk-sugar will be found very suitable for adminis- tration in this way. Dujardin Beaumetz speaks very highly of powdered meat, of which he gives 100 to 400 grammes daily, stirred up in milk, chocolate, or soup. A daily ration consisting of 3 pints of milk, to which have been added 3 ounces of milk-sugar (previously dissolved in water by boiling), £ pint of cream, and a pint of soup strengthened by some proteid preparation, such as Nutrose, Plasmon, Tropon, or powdered meat, will be amply sufficient to maintain the nutrition of a patient who is confined to bed, and is very easily administered by the tube. 1 See Dujardin Beaumetz, Clinique Therapeutique, i. 403. 37-2 INDEX 'Abdominal plethora,' grape cure in, 257 Abel, on action of alcohol on heart and circulation, 343 on restricted use of alcohol, 350 Absorbability expresses physiological digestibility, 8 of different foods, 10 Absorption : from mixed diet, 13, 14 individual differences in capacity for, 15 influence of mineral matters on, 286 of water, 301 of alcohol by stomach, 339, 360 of bran, incomplete, 213 of bread, 209 relative, of white and wholemeal bread, 210 of carbohydrates, 12 of carbohydrates in bread, complete, 210 of cocoa, 331 of eggs, 158 of fat, 1 1 of fish, 82 of food in intestine, 429-431 in stomach, 428 of fungi, imperfect, 267 of green vegetables, 257 of human milk in infant's intestine, 445 of koumiss and kephir, 142 of meat, 65, 68 of milk, 123 of nuts, 261 of porridge, 223 of potatoes, 241 of proteids, 11, 13 in bread, defective, 209 in wholemeal bread, 212 of pulses, 232, 233 of rice, complete, 229 of vegetable foods, 165 obstacles to, 166, 167 proteids difficult to absorb, 169, 170, 173 relative, of animal and vegetable foods, 166 Absorption of wholemeal bread, 211, 213 defective, 212 Achylia, dietetic treatment, 530, 333 Acid, acetic, basis of vinegar, 286 in wine, 374, 377 oxalic, in food, 297 phosphoric, in food, 295 Acidity of foods, 299 of gastric contents, 413 relation of, to morbid gastric sensa- tions, 421 total in sound wine, 377 Acids, action of, in wine, 392 in meat, 60 fixation and neutralization by casein, 144 Adonis, natural mineral water, 310 Adult diet, comparison with infant diet, 440, 441 Adulteration of bread, 206 of wheat-flour with maize-flour, 224 Aerated bread, igg, 220 milk, 121 waters, artificial, 306-308 danger of distilled water, 309 310 recipes for, 308 varieties, 307 Agassiz : belief that fish was specially good for brain, 83 Age, influence on amount of food, 45 of children, food at different ages, 469 See also Old Age Akoll biscuits in diabetes, 497 Aladdin Oven, 410 Albene, preparation of nuts, 260 Albulactin, 459 Albumin, average daily secretion of, in subacute nephritis under different diets, 452 in milk, 451 Albuminuria, transient, how produced, 53 Albumoses, incapable of exciting gastric secretion, 418 Albuminoids in dietary of diabetes, 151, 489 Alcohol (ethyl alcohol), 337-395 absorption of, 339, 340 580 INDEX 58r Alcohol, amount for daily consumption, 348 as food, 344, 345, 346 as a stimulant, 340-344, 391 avoidance in renal disease, 541 chemical composition of, 337 effects of, on the brain, 338, 340, 342 local, on tissues, 337 on circulation, 340, 342 on digestion, 338 on dilated stomach, 340 on heart, 340-344, 351 on metabolism, 344 on salivary digestion, 338, 369 on temperature of body, 342, 345 on stomach peristalsis, 338, 339 on human milk, 440, 441 physiological, 337-352 fat-sparer, 344, 345 forbidden in chronic nephritis, 544 idiosyncrasy in consumption of, 349 in bread, 199 in koumiss and kephir, 141 in wine, 374, 376, 385 produced by sugar fermentation, 278, 279 proportion of, in beverages, 354 protoplasm poison, 344 question whether a proteid-sparer, 346 relation to immunity, 351 requires no digestion, 340 use, in diabetes, 498 in disease, 351, 370 in fattening diets, 509 in fever and acute fevers, 343, 346, 351, 480, 482, 484-486 in health, 349 in neurasthenia, 516 in obesity, 370, 511 Alcoholic beverages. See Beverages Alcoholism, 347 vegetarian and lacto-vegetarian diet for, 550 Ales, 364-371 mild and bitter, 366 sugar-free, 371 Aleurdnat, 561 home-made diabetic bread prepared from, 497 mixture with flour, 216 Algae as food, 268. See also Irish (or Carraigeen) moss Alkalies, addition to milk, 121, 122 Alkalinity of foods, 299 Allen, caffeine and tannin in tea, 317 composition of sausages, 75 fusel-oil, 356, 363 meat-extractcontaining meat fibre, 96 Allenbury Foods, 46! 470 Malted, 468 Allspice, 286 Almonds as fat food, 570 nutritive value of, 262 Alpine climbing, sugar as muscle-food in, 284 Alum whey, 132 ' Amanita,' toxin of fungi, 263 America, chemical composition of mill- ing products obtained in, 194 modification of cow's milk for in- fants, exact science in, 459 Amylose, 161 Anaemia, zomotherapy in. 556 <" in relation to iron in foods, 293 Aneurysm, dietetic treatment, 540 restriction of water in diet in cases of, 303 Aniline, colouring matter of sweets, 276 Animal foods, 58-75 mixed, and vegetable diet, relative bulks, 167 and vegetable foods, relative ab- sorption, 166 preponderance of proteid in, 172 note Animals, analytical feeders, 184, 346 Anstie, food value of alcohol, 378 wines in health, 388 Antiseptic action of gastric juice, 427 Antiseptic, intestinal, milk as, 126 Aphrodisiac properties of fish diet, 83 Apollinaris, natural mineral water, 309 Appetite, 416, 417 definition, 416 provoked by artificial concentrated foods in illness, 537 by peptone preparations, 539 Arctic Regions, amount of food required in, 49, 50 alcohol in, 343 Armour's Beef Juice, loo, 101 Arrowroot, 246 addition to milk in fever diet, 487 British, prepared from potato-starch, 230 chemical composition, 246 digestibility, 246 economic value, 247 nutritive value, 247 See also Bermuda arrowroot, Farina, Tous les mois Arterial tension high, dietetic treat- ment, 540 Arthritis, rheumatoid, diet in, 519 Artichokes, 245 in mild diabetes, 245 inulin in, 245 Artificial feeding, 546-554. See also Gavage Artificial foods, 559-570 degree of concentration, 559, 560 5 82 FOOD AND DIETETICS Artificial foods, physiological defence, 560 suggestive value to provoke appetite, 561 carbohydrate, honey, 567 malt- extracts, 566, 567 milk-sugar, 568 fatty, 568-570 cod-liver oil emulsions, 569 Cremalto, 569 Lipanin, 569 Miol, 569 Pancreatic emulsion, 569 spermaceti, 569, 570 Virol, 569 proteid, digested, or peptone preparations, 562-566 Aleuronat, 561 Carnrick's Peptonoids, 564 Glidene, 561 home-made peptonized food, 566 legumin, 561 milk somatose, 564 Mosquera beef - meal, 107 pemmican, 537 plantose, 561, 562 Roborat, 561 Somatose, 563 Tropon, 562 See also Infant foods undigested, 561 Ascites of cirrhosis, salt-free diet in, 557 Ashby's method for preparing humanized milk, 458 whey for infants, 458 Asparagin in potatoes, 242 in asparagus, 249 Asparagus, asparagin in, 249 Ass, rarely suffers from tuberculosis, 450 Ass's milk, comparison with human milk, 449 composition, 449 Assimilation, function of, regulated by central nervous system, 51 of sugars, 279 Atkinson's, Dr. Edward, Aladdin Oven, 4x0 Athletes, dietaries for, 38-41. See also Training Atwater, absorbability of different foods, 10 absorption of mixed diet, 14 analyses of different forms of bread, 202 diets of childhood, 45 experiment as to influence of mental work on food required, 41 Atwater, food value of alcohol, 346 note? standard dietaries, 31 standards of numbers of calories for different work, 36 table of actual dietaries, 32 Australian wines, 382 Avenine, 221 Aylesbury Dairy Company, analyses of humanized milk, 456 Backhaus, Dr., on foreign matters in milk, 117 modification of cow's milk, 459 Bacon, digestibility, 68 Bacteria, agency in ' ripening ' cheese, 147 pathogenic, in milk, n 6-1 18 restraint of destruction of .proteids in intestine by, 13 role of, in intestinal digestion, 424 Bailey's Cooker, 407 ' Bain-marie,' slow cooking apparatus, 407 Baking of meat, 400 Baking-powders, 200 chemical compositon, 200 Balfour, G. W., diet for cases of weak heart, 539 ' Ballast,' stimulus to peristalsis of in- testine, 14, 168, 189, 251, 536 Bamberger, fluids in chronic nephritis, 544 Banana, 257, 258 bulkiness of, 257 economic value, 258 percentage of chemical compositfon, 257 Banana-flour, 258 chemical composition, 258 nutritive value, 258 Bananina, 258, 469 Bananine Bread, 205 Banks Company's ales, 371 Bannister, analyses of tea, 316 on composition of raw and roasted coffee, 322 Banting diet, 504 risks of, 506 Bardswell and Chapman on dietetics of phthisis, 514 meat diet in phthisis, 514 Barker on glucose in subcutaneous feed- ing. 597 Barley, 226 chemical composition, 227 Barley-sugar, 274 Barley-water, 227 dilution of milk with, to aid digestibility, 120 • Barm ' used in fermentation of Scotch bread, 198 INDEX 583 Barrie's bitter beer, 371 Baumm, composition of human milk, 439 nursing mother's diet, 440 Bean, broad or Windsor, 235. See also Butter-bean, Kidney bean, Soy bean. Scarlet runner Beans, 235 avoidance in gout, 511 rich in sulphur, 231, 232, 235 Beaumont, visible observation of diges- tion in case of Alexis St. Martin, 424, 433 Beef, digestibility, 67 raw and boiled, composition of, 65 Beef-extracts, 92 composition, 96 containing meat-fibre, 96 claim to be regarded as food, 97 Beef-juices, 98 amount of coagulable proteid in, 100 artificial composition of, 101 expensive, 102 contain proteid in coagulable form, 108 objectiqns to, 101 See also Bovinine, Bovril Com- pany's juices, Brand's Essence, Leube-Rosenthal's Meat Solu- tion, Liquor Carnis, Raw Beef-juice, Taurine, Wyeth's Beef -juice Beef-powders, 107, 108, 109. See also Mosquera Beef Meal, Pemmican, Somatose Beef-tea, 104 composition and uses, 105, 106 method of preparation, 104, 105 preparations, composition of, 107 value exaggerated, 106 whole, 106, 109 See also Brand's Fibrous Beef- tea, Mason's Strong Beef-tea, Vril Albuminous Beef-tea Beer, 364-37 1 German, 350, 367 non-alcoholic, 371 stone ginger-beer, 308 ' substitute ' beer, 367 Beetroot, 244 rich in cellulose, 244 sugar in, 244 Beet-sugar, 272 chemical composition, 273 difference between cane-sugar and, 273 Bell, chemical composition of bread, 202 Bendles Meal Port Nutrient, 389 Benger's Food, 468, 471, 483 in fever diet, 483 Bergeat, comparative absorption of offal, 74 Berina, Montgomerie's, 221 Bermaline Brown Bread, 204 composition, 203 Bermuda arrowroot, 243 Beverages — alcoholic, 353-37 1 beer and ale, 364-371 brandy, 357 German beers, 365, 367, 368 gin, 359 liqueurs and bitters, 360 malt liquors, 364-371 moderate use permitted in atonic and flatulent dyspepsia, 532 porter and stout, 367 rum, 358 spirits, 353-364 whisky, 355357 wines, 372 in children's diet, 477 in constipation, 536 in diabetes, 371, 493, 498, 499 in gout, 370, 518 in obesity, 370, 371, 511 non-alcoholic, 371-395 Biedert's cream mixture for infants, 455, 456 Biliousness, dietetic treatment, 538 Binz on effect of alcohol on stomach peristalis, 338 on crude spirits, 364 Biogene, 143 home-made diabetic bread prepared from, 497 wafers in diabetes, 497 Bipsine Bread, 203, 204 Rusks, 476 Biscuits, 206, 207 chemical composition, 207 digestibility, 209 See also Snip's biscuit Bitters, 360 Bivo, 389 Black bread (Pumpernickel), 197 wasteful food, 228 Blane, Sir Gilbert, on potato in scurvy, 236 Bloater, nutritive value high, 84 Blood, abundant supply necessary, 41 expenditure in digestion of bulky diet, 180 influence of water on volume of, 300, 301 preparation from. See Beef-juice toxic material in, causing marginal gingivitis, 418, 642 Blood-substance not valuable as food, 72 5«4 FOOD AND DIETETICS Blubber, consumption in large amounts by Esquimaux explained, 50 Blyth, A. Wynter, analysis of barley- water, 227, 228 Boas's enema, 574 Boat crews, dietaries of, 40 Bohea tea, 314 Bomer and Konig, analysis of Liebig's Extract, 93 Boiling, 398 effects on milk, 116 of eggs, 398 of meat, 398 Bones, composition of, 78 in production of gelatin, 78 Boussingault, economic value of pota- toes, 242 iron in food, 291, 292 staleness of bread, 205 Boutroux on staleness of bread, 206 Bovinine, 101 Bovril, 96 Bovril Company's meat juices, 100, 101 Bovril Wine, 389 Bowels, distension from bulky diet, 179 koumiss in chronic catarrh of, 143 Boyce and Herdman, ' greening ' of oysters, 87 Brain, effect of alcohol on, 340, 342, 343 fish not valuable as brain-food, 83 importance of digestibility of food to brain-worker, 42 phosphorus as brain-food, 41 Brain-substance as article of food, 74 Bran, incomplete absorption, 210, 213 of wheat, igo, 192 alone removed by stone grind- ing, 192 retained by ' Frame Food pro- cess, 195 Brand's Essence, 100, 101 Fibrous Beef-tea, chemical compo- sition, 107 Brandl, digestibility of sugar, 277 Brandy, 357 in fevers, 486 ' Braxy " mutton, explanation and use of, 70, 71 Bread, 196-218 absorption, 209 relative, of white and whole- meal bread, 210 addition of meat to, 215 adulteration, 206 alcohol in, 199 and skim milk, 128 carbohydrates in, complete absorp- tion, 210 changes consequent on keeping, 205 chemical composition, 201, 205 Bread, cooking of, 206 diabetic. 496, 497 v digestibility, 208 economic value of, 217 jelly, method of preparing, 473 least bulky of vegetable foods, 166 ' leavening,' or fermentation by yeast, 196, 197 -making, ' sponge ' formation in, 198 gluten in flour, necessary for, 196 malting of, 204 mineral matters in, 210 moisture in, standard should be fixed, 201 nutritive value, 214-216 proteid in, defective absorption, 209 method of increasing, 215 staleness, 205, 206 waste in bread-making, 199 white, comparative composition of crust and crumb, 205 compared with Graham bread and entire wheat bread, 212 compared with wholemeal, 16 See also Aerated bread, Bermaline Brown bread, Bipsine bread, Brown bread, Entire Wheat bread, Hovis bread, Turog bread, Vienna bread, Wholemeal bread Bread Reform League directions for bread-making, 211 Breads, fancy, 204 malted, 204 patent, 204 Brewing, 365 Bright's disease, dietetic treatment, 543 See also Nephritis Brillat-Savarin. aphrodisiac properties of fisn diet, 83 instance of enormous consumption of oysters, 87 sugar as a muscle-food, 282 Broad bean, 235. Bromose, commercial preparation of nuts, 260 Bronchial catarrh, grape cure in, 257 Brose, 223 Brown bread, 207 cellulose in, 202 poorer in carbohydrates than white, 202 Brown, E. W., Iceland moss, 269 Bruce, Dr. J. Mitchell, milk diet in sub- acute nephritis, 543 on milk in nephritis, 531 Brunton, Sir Lauder, and Tunnicliffe, F. W., researches on digestibility of bread, 213 INDEX 585 Biichner on phosphorus as brain food, 41.83 Buckle, costliness of highly-carbonized food, 17 Buckwheat, 229, 230 Budin's method of preparing cow's milk for infants, 453 Build of body and amount of food, 44 Bulgarian bacillus in sour milk prepara- tions, 558 acclimatization in intestine, 558. Bulkiness of vegetable foods, 164, 166, 178 obstacle to complete digestion and absorption, 167 physiological effects, 179 of banana, 257 of potatoes, 242 Bulkley, dietetic treatment of psoriasis, 547 Bullen, F. T., method of cooking prac- tised by Kanakas, 411 Bunge, chemical composition of gelatin, 77 on dangers in dietetic use of sugar, 282 on iron in food, 291 on salt craving, 165, 295 Burgundy, 373, 381 Burton ale, composition, 365, 367 analysis, 369 Busch, time of escape of food from stomach, 423 Bushuyez's typhoid fever diet, 487 Butter, 134 compared with jam, 136, 137, 477 digestibility easy, 135 fat in, 134, 570 nutritive value of margarine nearly equals that of, 136 preservation of, 134 substitutes for, prepared from nuts, 260 Butter-bean, 232 Butter-milk, 122, 138 cheap source of proteid, 138 chemical composition, 138, 141 diuretic properties, 138 Butyric acid, 135 Cabbage, 249, 250 valuable antiscorbutic, 252 Caffeine in tea, 317-320 effect on tissue waste, 329 source of uric acid, 335 stimulating action, 328, 329, 332 Caird on subcutaneous injection of oil, 578 Calcium casein, 115 in milk, 290 in yolk of egg, 155 sources and function of, 287 Calcium p?.ricasein, 115, 120 Cali's-foot jelly, 76, 78 Californian wines, 382 Calorie standard, 4 method of application, 6 value of different foods, 426, 508 of human milk, 446, 447 Calorie*, amount required for work of different degrees of severity, 35, 36, 43 , large number yielded by sugar, 281 obtained from bread, 217 percentage lost through non-absorp- tion, 12 reduction in obesity diet, 503, 504 Camerer, daily amount of human milk, 442 Cameron, Miss I. D., dietary of students halls of residence in Edinburgh, 34 Campbell, H., on mastication, 412 Cane-sugar, 270 avoidance in hyperchlorhydria, 53i chemical composition, 271, 273 difference between beet-sugar and, 273 early records of, 270, 271 proportion in commercial and home- made jams, 276 Cannon, movements of pyloric end of stomach, 422, 423 Caramel, conversion of sugar into, 397 Carbohydrate foods, artificial, 566-568 Carbohydrates, absorption, 12 amount required in diet, 26 and fats increase in fattening diets, 512 as proteid sparers, 23 as sources of muscle energy, 37 brown bread poorer in, than white, 202 constituent of milk, milk-sugar, or lactose, no degree of concentration possible, 560 effect of heat on, 396 foods rich in, sparing use in hyper- chlorhydria, 531 in bread, complete absorption, 210 in cereals, 189, 493 in diabetes diet, 488-492 question of restriction, 498 in diet of infancy, 435-489 in fruit, 254, 493 in green vegetables, 250, 493 in milk products, 493 in pulses, 493 abundant, 232 in rectal feeding, 571 in roots and tubers, 493 586 FOOD AND DIETETICS Carbohydrates in subcutaneous feeding, 553 in vegetable foods, 17, 161, 185, .493 intestinal, 571 of mixed diet, restraining effect upon destruction of proteids by putrefactive bacteria, 13 restraining effect upon intestinal putrefaction, 430, 431 sources of, in child's diet, 476 time of stay in stomach, 425 Carbon food cycle, 181, 182 Carbonaceous foods, limitation in head- aches, 546 Carbonic acid, excretion during rest, 42 Carbonic acid gas, dietetic disadvantages of, 310 aid to digestion, 310 Cardiac disease. See Heart disease dropsy, 524 dry diet in, 527 Carlsbad, gout dietary at 512, 517 Carnine and carnic acid in meat extracts, 94 Lefrancq, 100, 101, 556 dosage, 556 soluble food, 467, 470 Carnrick's peptonoids, 564 Carraigeen moss. See Irish (or Carrai- geen) moss Carrots, 244 rich in sugar, 244 Carr's ' Oaten,' 221 Casein bread in diabetes, 497 combination of, in Plasmon cocoa, 335 contains phosphorus, 144 dietetic advantages, 144 in milk, no, 115, 451 digestibility, method of increas- ing. 454. 455 digestion difficult 120, 141 intestinal absorption, 571 nutritive value, 144 precipitation in making of cheese, 146 preparations, 143-145 enrich diet in proteid, 144 note See also Casumen, Nutrose, Plas- mon (and Plasmon preparations), Protene Diabetic bread, Protene flour, Sanatogen Oaseinogen, 115 Cask, wine in the, 374 Casoid bread, and casoid meal bread, in diabetes, 497 Cassia, 286 Castor seeds, vegetable proteid in pure form from, 538 Casumen, addition to milk in feve» Het, s 4«3. 487 j preparation of casein, 143. x 44. 5°' Cathcart's apparatus for milk ster liza- tion, 118 Cauliflower, rapid digestion of, 42$ Caviare as article of diet, 85 Cayenne pepper, 286 Cellulose, beetroot rich in, 244 cause of defective absorption of wholemeal bread, 212 digested in experiments with men, 168 effect of cooking on, 401-404 in brown bread, 202 in fruits, 255 in vegetable foods, 161, 162, 166, 167 onions rich in, 245 useful as intestinal stimulant, 168, 169 Celsus, therapeutic value of milk, 133 Cerealine, chemical composition, 221) preparation of maize, 225 Cereals, 187-230 carbohydrates in, 188 chemical composition of, 188 fat in, 188 mineral matter in, 188 preponderance, 189, 493 products derived from, 190 proteids in, 187 Cerebos salt, 296 Chambers, T. King, evils of deficient diet, 57 fusel oil, 363 relaxation after meals, 433 whole beef-tea, 107 Champagne, 385 in fevers, 486 Chapman and Bardswell, dietetics of phthisis, 509 meat diet in phthisis, 514 Chapman's Whole Wheat Flour, 219, 469, 472 Cheese, 146-150 action of rennet on milk in forma- tion of, 146 agency of bacteria in ripening, 147 chemical composition, 148 digestibility, 148, 149 flavour of, how produced, 147 hard, 146 nutritive value, 149 precipitation of casein in making of, 146 proteid and fat essential compounds of, 147 soft, 147 Cheltine Infant's Food, 469 Maltose Food, 468, 471, 494 INDEX 587 Chemical composition of alcohol, 357 of arrowroot and sago, 246 of baking-powders, 200 of banana, 257 of banana-flour, 258 of barley, 227 of biscuits, 207 of bread, 201-205 of butter-milk, 138 of cane- beet- and maple-sugar, 271, 273 of cereals, and of products derived from cereals, 188, 189 of cheese, 148 of chestnuts, 262 of chocolate, 328 of coffee, raw and roasted, 323 of condensed mi k, 462, 463 of custard-powders, 159 of Devonshire cream, 133 of eggs, 152-156 of faeces, 425, 431 of fish, 78-80, 88, 89 of food less important to brain- worker than digestibility, 42 of Fromm's extract, 261 of fruit, 253, 254 of fruits (dried), 259 of fungi, 265 of green vegetables, 248, 249 of honey, 275, 543 of Iceland moss, 269 of Irish (or Carraigeen) moss, 268 of Italian pastes, 219 of johnny cakes, 224 of maize and special prepara- tions, 224, 225 of malt liquors, 368 of margarine, 136 of meat, 61 of Mellin's Food, 471 of milk (human), 473 of milks (different), 443 of mill-products of wheat, 194 of millet (Indian), 229 of nuts, 260, 262 of patent preparations of wheat, 219, 220 of peptone preparations, 541 of pop-corn, 225 of potatoes, 238, 241 of preparations of oats, 222 of proprietary infant foods, 461- 465 of pulses, 231, 234 of Revalenta Arabica, 235 of rice, 228 of roots and tubers, 237 of tea, 315-318 of tea-infusion, 318-320 Chemical composition of vegetable foo Js, 160-165 of wheat, 190, 191 of wholemeal bread, 214 of wines, 375, 395 Chemical tests of value of food, 4 Chestnuts, chemical composition, 261, 262 Cheyne, G. , on the advantages of purin- free diet, 511 Chicken, digestibility, 68 Childhood, diet, amount of each nutrient ingredient required at differ- ent ages, 474 deficiency in proteid disastrous, beverages, 477 dietaries and meals, 478 ratio of proteid to carbohydrates and fat, 474 requirements, 45, 46 sources of carbohydrate, 476 of fat, 475 of mineral matters, 477 of proteid, 475 use of sugar in, 476 Children, favourable influence of sugar on health and growth of, 282 relative values for food requirements at different ages, 45 relatively require greater amount of food than adults, 45 young, absorb milk better than adults, 125 Chittenden, amount of proteid required in diet, 24, iy6 digestion of meat, 66, 67 use of milk-powder, 462 and Cummins on digestibility of fish, 82 and Mendel, absorption of alcohol by stomach, 339 analysis of Burton pale ale, 368 analysis of Guinness's Dublin stout, 368 wine and digestion, 3go Chlorine, 298 Chocolate, 275, 328, 477 as fat food, 570 composition of, 328 Plasmon, 328 Chorea, dietetic treatment, 546 Church, Professor, analysis of oorn- fiour, 224 analysis of Iceland moss, 269 analysis of Indian millet, 229 analysis of mill-products of wheat, 194 chemical composition of wheat, 190 588 FOOD AND DIETETICS Cider, 387 Cinnamon, 286 Circulation, stimulating action of alcohol on, 341-344 disorders of, diet in, 538-540 Cirrhosis of liver, dietetic treatment, 537. 557 use of koumiss in, 143 Citrate of soda added to milk to aid digestion, 121, 454, 455 Citric acid in milk, 112 in tomatoes, 252, 298 lemonade in diabetes, 498 Clams as food, 88 Claret, 373, 380 Clarke and Cushing, liberal supply of water in typhoid fever diet, 488 Climate, influence on amount cf food, 48 Clothing in relation to food, 49 Clotting of milk, 115 distinguished from curdling, 114, 115, 120 in stomach, 119, 120, 121 Cloves 286 Coagulation of milk, 114 Cocacorn, 336 Cocoa, analysis of commercial forms of, 327, 328 allowed in diabetes, 498 avoidance in gout, 551 chemical composition of, 326328 digestion and absorption, 331 food-value, 335 homoepathic, 326 malted, 326 navy cocoa, 326 -nibs, 325 -nuts, nutritive value, 261 Plasmon, 335 soluble, 325 tannin in, 327 theobromine in, 327 See also Sanitas Health Cocoa Cocolardo, commercial preparation of nuts, 260 Cocoleum, commercial preparation of nuts, 260 Cocos butter, commercial preparation of nuts, 260 Cod-liver oil emulsions, 569 Coffee, 322 allowed in diabetes, 498 avoidance in cases of gout, 335, 55i beans, varieties of, 322 chemical composition of raw and roasted, 323 composition of infusion, 324 French, 324 history of, 322 Coffee, influence on salivary and gastric digestion, 329-335 , injurious effects, 327, 330 Life-Belt, 336 making of, 324 not a food, 334 stimulating action, 328, 329 Coffees, cereal, 336 Cohendy, acclimatization of Bulgarian bacillus in intestine, 558 Cold, resistance to, diminished by under- feeding, 55 Colitis, acute and ulcerative, dietetic treatment, 534 muco - membranous, dietetic treat- ment, Von Noorden's method, 534. 535 Plombiere's system, 534 Ransom's dietary, 535 Collagen, 59 yields gelatin, 59 Colostrum, 437, 438 Coma, diabetic, diet in, 500 Combustion in body, 4, 5 Condensed milk, 462-466 chemical composition, 462, 463 digestibility, 464 kinds of, 465 nutritive value and economy, 464, 465 sweetened, limitations of use, 459 Condiments and spices, 282 necessity for, 282 Congou tea, 314 Constipation, chronic, directions for diet. 534. 53°, 537 onions valuable in, 245 use of whey in, in cases of nephritis, 133 Contrexeville, natural mineral water, 310 Convalescence, fattening diet for, 513 use of koumiss in, 143 zomotherapy during, 556 Cookery of flour, 196 Cooking of edible fungi, 266 effect of, on carbohydrates, 396 on cellulose, 401-404 on digestibility of food, 390, 398 of meat, 66, 67 on fat, 397 on green vegetables, 250 on meat, 64, 66 causes loss of water, 64 on proteids, 396, 398 losses in, 404 method of, in Salisbury cure, 67 of bread, 206 of fish, 400 of foods, 396 411 of fruits, 255, 256 INDEX 589 Cooking of meat, 397-400 of potatoes, 237, 238 of vegetable foods, 401-404 retards digestibility of meat, 66, 67 slow, 400-405 contrivances for, 406-411 vegetable foods require long time in, 185 Coombs' Malted Food, 469 Corlette, analyses of barley-water, 227 Cornaro, temperance in old age, 46 Corn flakes, preparation of maize, 225 Cornflour, preparation of maize. 225 Corn Laws, repeal of, hygienic effects, 55 Corpulence. See Obesity Cow's milk, adulteration of, 113, 114 behaviour of, in intestine of infant, 453 chemical composition, 112, 141 variability in, 1x3 chemical differences between human and cow's milk, 450 density of clot in stomach, 453 digestibility of human and cow's milk compared, 452 of casein in, increased by add- ing citrate of soda, 121,455,456 fat in, 452 fermentation of, to produce kepbir, 140 infant's food prepared from, 467, 470 lecithin in, proportion less than in human milk, 445 modifications of, for infants, 453-460 mineral salts in, compared with those in human, 452 nitrogenous matters in, 451 tuberculous, 117 Cox's gelatin. 78 Crab as article of food, 85 Cramer, eggs and milk as proteid pro- ducers, 176 results of observations tarians, 179 Cream, 133 allowed in diabetes, 496 as fat food, 133. 134, 546 mixtures for infants, 455, See also Devonshire cream Creamota, 221 Creatin in meat extractions, 94, g7 Creatinin in meat extractions, 97 Cremalto, chemical composition, 569 Crookes, Professor, loss of nitrates to soil, and method of fixing free nitrogen, 183 Cucumber, 250 percentage composition of, 250 Cummins and Chittenden on the diges- of meat, 66, 67 on digestibility of fish, 82 on vege- 456 Curdling of milk distinguished from clot- ting, 115 Cushing and Clarke, liberal supply of water in typhoid fever diet, 488 Custard-powders, chemical composition, 159 ' ' substitutes ' for eggs, 159 Cyclone Wholemeal Bread composition, 203 Cytos Brown Bread, composition, 203 Dancel, restriction of fluids, 509, 510 Daren Brown Bread, composition, 203 Date as food, 259 Dauglish's method of preparing aerated bread, 199 Debility, zomotherapy in, 556 Delirium tremens, koumiss recommended i°. 143 Dennig on influence of water on absorp- tion, 304 D'Errico, subcutaneous administration of yolk of egg, 578 Devonshire cream, 133 chemical composition, 133 use in diabetes, 133 Dextrin prepared from potato starch, 239 in vegetable foods, 162 Dextrose, or grape-sugar, "274, 372 Diabetes, alcohol in, 352 artichokes in, 245 avoidance of junket in, 115 beverages, 352, 493 carbohydrates in, 498 chemical substitutes for sugar used in, 287 diet in diabetic coma, 500 foods available, as sources of albu- minoids, 494 carbohydrates, 492, 493 fat, 491 proteids, 491 increase of, in relation to increased consumption of sugar, 282 lsevulose, in, 498 meals, 499 no fixed diet for, 491 oyster forbidden in, 86, 87 pea-nut as food in, 236 restriction of carbohydrates, 488- 492 richness in fat, 490 tea allowed in, 498 toast to be avoided in, 497 turnips need not be forbidden in 244 use of Devonshire cream in, 133 fruit and fruit-carbohydrates in, 254. 498 milk in, 494, 495 test diets in, 496 59° FOOD AND DIETETICS Diabetic breads, 496, 497 (home-made), sources for prepara- tion, 497. See also Casoid bread and Casoid meal bread, Protene djabetic bread, Plasmon diabetic biscuits (sugar-free) milk, preparation, 494, ,495 Diarphoea, acute and chronic, diets for, , 5 2 3> 533 nervous, no special diet for, 534 acute, of infancy, dietetic treatment. 536 causation of, by meat extractives in large amounts, 108 by peptones, 563 chronic, result of purely vegetable diet, 179 infantile diet in, 524 Diet, mixed, absorption from, 13 mixed, justification for, 19 restriction to single article of, dangerous, 30 standard, 31 application, 33, 34 construction, empirical method, 25 physiological method, 25 Dietary of students at Edinburgh, 34 Dietaries, actual, 32, 33 Digestibility, popular and physiological sense, 8 of arrowroot, sago, tapioca, 246 of bacon, 68 of beef, 67 of biscuits, 209 of bread, 208 of butter, 135 of casein in milk, method of in- creasing, 454, 455 of cheese, 148, 149 of chicken, 68 of condensed milk, 464 of eggs, 157 of fish, 81, 82 of food, more important to brain- worker than chemical composi- tion, 42 of foods, effect of cooking on, 396, 404 of fruit, 256 of fungi not easy, 266 of game, 68 of gelatin, 77 of green vegetables, difficult, 251 of human milk, 445, 452 of invert sugar, 278 of koumiss and kephir, 141 of meat, 65, 67 idiosyncrasy in, 68 retarded by cooking, 66, 67 Digestibility of milk, 1 19-123 boiled and unboiled, compared, 121, 122 human and cow's, compared,452 methods of improving, 120, 121, 448 of mutton, 67 of nuts, 260 of oyster easy when raw, 87 of pork, 68 of potatoes, 241 of pulses, 232 of rice, 229 of rye, 228 of rye bread, 213 of starch by infants, 472 of sugar, 277-279 of veal, 67, 68 of vegetable foods, 165, 166 obstacles to, 166. 167 Digestion, action of malt liquors on, 369 action of spirits on, 361 aided by carbonic acid gas, 310 diminished by underfeeding, 57 in intestine more important than in stomach in infants, 445 in large intestine, 423 in mouth, 412 in stomach, 407-423 influence on, of alcohol, 338-340 of hunger and appetite, 416, of Liebig's Extract, 95 of malt extracts, 567 of peptones, 562 of rest and exercise, 433 of salt, 294 of tea, coffee, and cocoa, 329-335 of water, 303 of wine, 390, 391 intestinal, 429-431 bacteria in, 424 of casein, 120 of different foods, rate of, 424-427 of food in health, 406-427 X-ray observations on. 420 of meat, 65, 66 of milk, how aided, 120, 121 of mixed meal process summarized, 43i. 432 of starch in stomach, 414 rate in case of different foods, 424, 426 stimulated by clear soups, 91 Digestive organs, enfeeblement due to purely vegetable diet, 179 Diphtheria conveyed by milk, 117 Disease, alcohol in, 362 communicated by pathogenic bac- teria in milk, 116, 117 INDEX 59« Disease, feeding in, principles of, 479- 548 malt liquors in, 351, 370 milk as food in, 123, 129 resistance to, on vegetable diet, 180 on proteid diet, 175 Dittman, tannic acid in tea, 319 Diuretic, milk as, 129 properties possessed by koumiss, 142 Donders, incomplete absorption of bran, 210 Donkin, use of milk in diabetes, 494 value of milk as food in disease, 130 Dorina Nursery Biscuits, 476 Dough, 197, 198 Dripping, value of, as food, 138 Dropsy, cardiac, salt-free diet in, 557 Dublin, diet of working-class families in, 34 Duck, composition of, 63 Dujardin-Beaumetz, composition of wine, 375 meat and beef powders, 108 Dukes. Clement, childhood diet, 475 division of meals in schools, 415 results from deficiency of green vegetables in diet, 252 Dulcin, chemical substitute for sugar, 287 Dunlop, J. C, prison diets in Scotland, 34 Duodenum, passage of food through, 429 Duplex Boilerette, 407 Dupre on constituents of wine, 377, 378, 386 Dutch Butter. See Margarine Dysentery, dietetic treatment, 534 Dyspepsia, acid, so-called oxaluria, variety of, 298 atonic or flatulent, dietetic treatment, 53i. 532 functional, 529 dietetic treatment, 423, 529 importance of pancreatic diges- tion in, 430 importance of use of invert or diluted sugar in, 278 varieties, dietetic treatment, 530 See also Flatulence, Hyperchlor- hydria Eastes, Dr., tubercle bacilli in milk, 117 Ebstein's diet for obesity, 506 Economic tests of value of food, 16 value of arrowroot, sago, tapioca, 247 of banana, 258 of condensed milk, small, 465 of fish diet, 84 of maize, great, 226 of meat, 70 Economic value of potatoes, 242 of sugar, 281 of vegetable foods, 181 Eczema, diabetic, how produced, 277 dietetic treatment, 547 due to deficiency of green vegetables in diet, 252 Edinburgh, diet of labouring classes as estimated by standard die- taries, 34 found to be insufficient, 56 students at, dietary, 34 Egg-albumin, 151 Egg-shell, composition, 151 Egg-white as substitute for raw-beef juice, 102, 109 composition, 151 incapable of exciting gastric secre- tion, 418 Eggs, 150-159 absorption, 158 and milk, supplement to vegetarian diet, 176 boiling of, 398 changes in, when kept and when rotten, 156 chemical composition, 152-156 percentage composition of white and yolk of, 152 same in eggs with dark or with white shells, 155 condensed, 158, 159 digestibility, 157 idiosyncrasy in, 158 nutritive value, 158 preparation of, as infant food, 473 proteid-producers, 176 purin-free, and permissible in gout diet, 155 substitutes for, 159 supplement to vegetarian diet, 176 See also Yolk of egg Ehrstrom, casein enemata, 571 Eichhorst, casein enemata, 571 Elastin, 59 Empirical method for construction of standard dietaries, 25 Endosperm of wheat, 190, igi\ Enemata, nutrient. See Rectal feeding Energy engendered by meat diet, 174 potential, amount of Calories re- quired for, 35, 36 amount to be contained in diet, 25 property of nervous system, 174 sudden and sustained, strength factors severally producing, 174, 175 supplied by proteid, 175 Energy value of foods, 7 592 FOOD AND DIETETICS Entire Wheat Bread, Wheat Bread and Graham Bread compared with, 212 Epilepsy, diet in, 545 Equilibrium, nitrogenous, 21 Esbach, oxalic acid in food, 297 Esquimaux, consumption of blubber by, explanation, 50 Ethers in wine, 378, 395 Ethyl alcohol. See Alcohol Ewald's enema, 550 Ewell's analysis of commercial cocoa, 328 Excreta. See Fasces Exercise, effect on muscle-fibre, 59 influence of, on digestion, 433 Extractives in human milk, 437 in meat, 61 contain no nutritive value, 61 in vegetable food, 164 in wine, 379, 394 presence of, constitutes chief value in Liebig's Extract, 93 F^ces, chemical composition, 431 foetid, production of, 430, 431 ^formation and composition of, 431 influence of diet on water in, 300 nitrogen in, source of, 170 Faeces-producers, foods as, 10 Fairchild's Peptogenic Milk Powder, 461 Fallacies, dietetic, 16 Farina, diastased, or English arrowroot, 247, 469 Farola, 219 Fat, absorption of, 11 intestinal, 571 abstinence from, and liability to tuberculosis, 418 amount required in diet, 26 and proteid, compounds of cheese, 147 artificial fat foods, 568 costliness of, 17 deficient in green vegetables, 251 in pulses, 232 in rice, 229 degree of concentration possible, 560 digestion of, how effected, 429 effect of heat on food-fat, 397 in almonds, 570 in butter, 134, 570 in cereals, 188 in cheese, 147 renders its digestion difficult, 150 in chocolate, 570 in cream, 133 in diabetic diet, 485, 488, 489, 491 in diet of infancy, 434 in phthisis, 513, 514 Fat in meat, 59 69 in rectal feeding, 571 in subcutaneous feeding, 577 in toffee, 570 in vegetable foods, 164, 169, 171 nutritive value, 171 incapable of exciting gastric secre- tion, 419 interdiction in jaundice, 430 large article of diet in cold climates, 5° of body, effect of sleep on, 42 of milk, in, 570 of cow's milk, 452 of human milk, 440, 446, 450 variable ingredient, 436 reliable gauge of quality, 114 proteid-sparer, 22 sources of, in child's diet, 475 starvation, effect of, 431 time of stay in stomach, 425 Fattening diet, 511-516 in convalescence, 513 in wasting diseases, 513 increase of carbohydrates and fats in, 512 in neurasthenia, 513, 515, 545 in rickets, 522 Feer, amount of milk required by infant daily, 443 Fermentation of bread, process, 196, 199 of koumiss, 141 of wine, 373, 374 Fever diet, 480-488 advantage of liberal feeding, 477, 478 alcohol in, 343, 346, 484-486 beverages, 484 fluid diet, 482-486 frequency of feeding, 484 koumiss in, 143 liberal supply of carbohydrates, 482 milk in, 129, 483 nutritive constituents necessary, 481 use of Mostelle in, 257 See also Rheumatic Fever, Typhoid Fever Fick, sugar in fever diet, 483 Figs, 259 nutritive value, 259 Filtering of water, 306 Finkler, Dr., Tropon first prepared by, 562 Fish, 78 absorption, 82 aphrodisiac properties of fish diet not proved, 83 chemical composition, 78-80, 88, 89 cooking of, 400 digestibility, 81, 82 economic value, 17 INDEX 593 Fish, 'fat,' 79, 82 digestibility, 82 iodine in, 298 lean, 79, 82 digestibility, 82 leprosy caused by fish diet, 83 Marvis, patent food derived from, 85 methods and effect of cooking, 400 not rich in phosphorus, 83 not valuable as brain food, 84 nutritive value, 83 •offal' of, 85 preserved waste matter, 79, 81, 84 Flatulence in functional dyspepsia, dietetic modification for, 528 in heart failure, dietetic modifica- tions for, 539 produced by certain pulses, 231 Flavour of fruits, use of, 256 of meat, 61 Fleischer on exercise after meals, 433 Flesh of animals which have died of disease as food, 70, 71 Fletcher, H., on mastication, 412 Flint, insufficient feeding in relation to cold, 55 Florador, 2 1 9 Florence and Mairet, food required during mental labour, 41 Flour, 193 addition of malt-extract to, 204 of various substances to flour to increase nutritive value of bread, 215, 216 adulteration with maize-flour, 224 cookery of, 196 gluten in, alone renders bread- making possible, 196 'self-raising,' 200 varieties, 193 See also ' Banana flour, ' ' Frame Food ' process, ' Graham ' flour, " Households ' flour, ' Hovis ' flour Fluorine, 298 Food-fruits, 256, 257 Food-value of alcohol, 344, 345, 350 of cocoa. 335 of coffee, 332, 333 of condensed milk, 464 of human milk, 445 of malt-extracts, 566, 567 of malt liquors, 370 of tea, 332, 333 of treacle and golden syrup, 567 See also Nutritive value Football players, value of sugar in diet of, 284 Force, 220 chemical composition, 220 Forced feeding, 519 Forster, antiscorbutic action of malt infusion, 52 1 effect of cooking on water in foods, 405 salt craving, 295 Fothergill, exaggerated value of beef- tea, 106 Fowl, young, composition of, 63 ' Frame Food ' process for retention of bran of wheat, 195 diet, 469, 472 France, Central, chestnut as article of diet among peasants of, 262 Franklin, Sir John, amount of food required in Arctic regions, 49 Fraser, effect of tea, coffee, and cocoa on digestion, 329 French and Germans, dietetic capacities compared, 52 French coffee, 324 French or kidney bean, 235 Frogs' legs as article of food, 88 Fromm's Extract, chemical composition, 261 commercial preparation from nuts, 260 Frozen meats, 70 Fruit, stewed, laxative action, 256 Fruit-sugar, or lffivulose, 274, 372 Fruits, 252 carbohydrates in, 254, 493 cellulose in, 255 chemical compositon, 253, 254 cooking of, 255, 256 digestibility, 256 dried, 259 chemical composition, 259 flavour and odour, 255, 256 hevulose in, 254 mineral constituents, 255 nutritive value, 256, 257 pentose in, 255 sugar in, 254 use of, in constipation, 536 in diabetes, 254, 493 valuable antiscorbutic, 255 See also Food-fruits Frumenty, ig2 Frying of fish, 401 Fuller, phosphorus in food, 296 Fungi, 263 absorption imperfect, 266, 267 digestibility of, not easy, 267 edible and non-edible, how to dis- tinguish, 263 chemical composition, 265 nitrogen in, 266 nutritive value exaggerated, 267 poisonous properties, 263, 264 See also Mushrooms, Toadstools 38 594 FOOD AND DIETETICS Fusel-oil, 354, 356, 363 Fuster, raw meat diet and alcohol in tuberculosis, 556 Gaertner's Fettmilch, 457 Galen, difficulty of digestion of pulses, 232 therapeutic value of milk, 130 Gall-stones, dietetic treatment, 537 Game, digestibility, 68 wild, flesh of, superior to that of home-fed, 61 Gas Griller, ' Unique,' 393, 3gg Gastralgia, dietetic treatment, 533 Gastric juice, antiseptic action of, 427 secretion of, 416 action of spices on, variable and inconstant, 285 foods incapable of exciting, 418 specific kinds for particular foods, 418 stimulated by clear soup, 91, 419 by peptone preparation, 5 6 3 powerfully by Liebig's Extract, 95, 108, 418 Gastric ulcer, 524 dietetic treatment, 524-526 by Lenhartz method, 525 rest of stomach in arranging diet for, 524 Gastritis, acute, dietetic treatment, 526 chronic, dietetic treatment, 526 avoidance of substances irritating gastric mucous membrane, 526 Gautier, solid constituents of wine, 376 Gavage, 579 Gelatine, chemical basis of jellies, 76 commercial, 78 cost of, 78 Cox's, 78 digestibility of, 77 isinglass purest form of, 76 Nelson's, 78 nutritive value, 7^ powerful proteid-sparer, 22, 77 produced from bones, 78 yielded by collagen, 59 Gelatinization of starches, 394 Germ breads, 216. See also Hovis bread of wheat, 190, 191, 192, 194 removed by process of roller milling, 192 retained by Smith's patent (' Hovis ' flour), 195, 204 German Army, beneficial results on muscular exertion from use of sugar, 283 Germans and French, dietetic capacities compared, 52 Gin, 359 Ginger, 286 Gingerade, 308 Ginger ale, 308 Ginger-beer, 308 stone, 308 Giraud on incomplete absorption of bran, 210 Glaxo, infant-food, 467, 470 Glendinning's Wine, 389 Glidine, 561 home-made diabetic bread prepared from, 497 Globenaris, aerated distilled water, 307 Glucose, commercial, 276 Glucoses, the, 270, 274 Gluten in different kinds of wheat, 193 in flour alone renders bread-making possible, 196 Gluzinski, digestibility of eggs, 157 Glycerine in wine, 379 Glycero-phosphoric acid, 296 Glycogen, conversion of sugar into gly- cogen by liver, 279, 280 in oyster, 86 Glycosuria, alimentary, causes of, 280 gouty, dietetic treatment, 500 Goat's milk, 450 Goitre, exophthalmic, and heart irrita- bility, vegetarian or lacto-vegetarian diet in, 550 Golden syrup, 274, 567 Goodfellow, absorption of proteids of wholemeal bread, 211 changes which bread undergoes on keeping, 205 economic value of bread, 218 researches on digestibility of bread, 213 wholemeal bread, 213 Goodhart, dietetics of gravel, 520 Goose, composition of, 63 Gout, avoidance of tea and coffee in, 335 avoidance or restriction of uric acid-producing foods and bever- ages in, 72, 73, 232, 516 avoidance or restriction of meat in, 517 beverages in, 518 chemical substitutes for sugar used in, 287 chronic articular, Salisbury's diet in, 553 diet in, 311, 516, 518 dietary at Carlsbad, 517 INDEX 595 Gout, influence of wine on, 393, 394 Gouty glycosuria. See Glycosuria ' Graham ' Bread compared with white bread and entire wheat, 212 ' Graham ' flour, composition of, 201 Graham, waste in bread-making, 199 Gramalt, 567 Granola, 219 Granuto, 219 Grape, 256 juice of, 372 Grape-cure, 256 in abdominal plethora, 257 in chronic bronchial catarrh, 257 Grape-nuts, 220 chemical composition, 220 Grape-sugar, or dextrose, 274, 372 Grape-wines, non-alcoholic, 390 Gravel, avoidance of rhubarb in cases of, 252 dietetics, 519. See also Uric acid gravel Graves' disease, dietetic treatment, 546 Greek wines, 385, 395 Green on tannic acid in tea, 315 ' Greening ' of oysters, 88 Gregor, K. , fat in human milk, 436 Grinding wheat by stone, an old method, 192 bran alone removed by this process, 192 Groats, 221 Gros, rectal feeding, 573 Grunbaum, O. , enemata of ox-serum, 575 Griitzner, reverse peristalsis, 572 Guinness's Dublin Stout, 368 as soporific, 370 Haddock, nutritive value same as that of sole, 17, 84 Haemoglobin, digestibility and absorp- tion, 72, 73 in meat, 60 iron in haemoglobin, and derivatives ill-absorbed, 72, 292 Haig, A., lacto- vegetarian diet (purin- free articles), 552 Halliburton, W. D., F.R.S., digestibility and absorption of haemoglobin, 72, 73 Hammarsten, constituents of whey, 457 Hammond, food value of alcohol, 345 attempt at restricted diet, 30 Hare, F. E. , system of diet of, 552 oxidation of proteids under, 555 Harley, Vaughan, personal experiment on assimilation of cane-sugar, 281 experiments with sugar as a muscle-food, 283 Hart, digestion of casein, 120 phosphorus in food, 296 Harvey's Sugar-free Ale, 366 Haughton, distinguishing characteristics of sustained strength and sudden energy, 174, 175 Headaches, dietetic treatment, 546 vegetarian and lacto-vegetarian diet, for, 550 Health , amount of food required in, 20-34 alcohol in, 319, 391 Heart, stimulating action of alcohol on, 34°. 34 1 Heart disease, dietetic treatment, 538-540 dry diet in, 539 flatulence in, treatment, 539 Heart-failure, flatulence accompanying, diet for, 539 Heart-irritability, abnormal, of nervous origin and in exophthalmic goitre, vegetarian or lacto-vegetarian diet for, 55° Heart-substance as article of food, 72 Heat and work producers, 4 Hercules Patent Meat-juice Press, 98 Herdmann and Boyce, 'greening' of oysters, 87 Herring, nutritive value high, 84 Heubner, results of feeding infants with Soxhlet's diluted milk, 456 Higgins, H., mastication and digestion, 412 High tea, why injurious, 331 Hippocrates on bad effects of under- feeding in childhood, 56 on choice of food for patients, 480 therapeutic value of milk, 130 Hirschfeld's diet for obesity, 507 on body-weight and food in relation to season, 50 Hock, 372, 381 Hcesslein, V., iron in food, 293 Hoff s Malt Extract, 566, 567 Holt, schedule for feeding infants, 444 Hominy, chemical composition, 225 preparation of maize, 225 Honey, 275, 543 chemical composition, 275, 567 Hony White Bread, composition, 203 Hoppe, rectal absorption of sanatogen, Hops, 365 Horlick's Malted Milk, 467, 470 in fever diet, 483 Horseflesh, prejudice against, 70 Horse-serum, subcutaneous feeding with, 577 Hospital or nursing home, treatment of diabetes should begin in, 501 ' Households ' Flour, 193 ' Hovis' Babies' Food No. i, 468, 471 ' Hovis ' Bread, 204, 216 ' Hovis ' Flour, germ retained in, 195, 204 596 FOOD AND DIETETICS ' Hovis ' Food No. 2, 469 Hughes, tannic acid in tea, 319 Humboldt on the banana, 258 Hundhausen, introduction of Aleuronat, 216 Hungarian wines, 381, 395 Hunger, 416, 417 definition, 416 without appetite, 417 Hiippe on slow cooking, 406 Hydrochloric acid, chief agent of pan- creatic secretion, 429 Hyperchlorhydria, dietetic treatment, . 530 in functional dyspepsia, dietetic modifications for, 531 Hysteria, vegetarian or lacto-vegetarian diet in, 550 Iceland moss, chemical composition of, 269 Ices, avoidance of, 428 Idiosyncrasy and alcohol consumption, 349 Illner on nursing mothers' diet, 440 Illness, composition of human milk in, 439 Immunity, relation of alcohol to, 351 Inanition, death from, point when it ensues, 54 Indian corn. See Maize Infant diet, in acute diarrhoea, 536 carbohydrates in, 435 comparison with diet of adult, 446 daily amount of milk required, 442, 443 importance of fat in, 434 in infantile diarrhoea, 536 methods of preparing cow's milk, 453 mineral ingredients, 435 pas teurization and sterilization of milk, 460 physiological requirements, 434 proprietary infant foods, 466- 470 regularity in feeding, 444 schedule of amounts required, 442 schedule of times for feeding, 444 substitutes for human milk, 448-473 . summary of rules for feeding infants, 472 use of condensed milk, 462-466 of partially peptonized milk, 461 of water, 436 of whey, 457-459 Infant foods, human milk, 436-447 milk, cow's, 453 human, 436-453 proprietary : Allenbury Foods, 467, 470 Allenbury Malted Food, 463, 468 Bananiria, 258, 469 Benger's Food, 468, 471, 483 Carnrick's Soluble Food, 462, 467, 470 Chapman's Whole Wheat Flour, 469, 472 Cheltine Infants' Food, 469 Cheltine Maltose Food, 468, 47i. 494 comparative value, 470, 471 compared with dried human milk, 471 Coombs' Malted Food, 469 Diastased Farina, 469 Frame-food Diet, 469, 472 Glaxo, 467, 470 Horlicks Malted Milk, 467, 470 * Hovis ' Babies' Food No. 1, 468. 471 ■ Hovis ' Food No. 2, 469 Lak Cit, 468 Maltico, 468 Manhu Infant Food, 467, 47°. 494 Mellin's Food, 468, 471 milk, human, dried,' 467 milk products requiring water, 467, 470 Milo Food, 467, 470 Moseley's Food, 469, 471 Muffler's Food, 467, 470 Neave's Food, 469, 472 non - predigested starch foods, 469, 472 Ridge's Food, 469, 472 Robinson's Groats, 469, 472 Robinson's Patent Barley, 227, 469, 472 Savory and Moore's Food, 468, 471 Scott's Oat Flour, 469 Theinhardt's Soluble Infant Food, 468 transformed starch foods re- quiring milk, 468,469,470 Infants absorb milk better than adults, 125 digestibility of starch by, 472 intestinal more important than gastric digestion in, 445 Insomnia, action of stout on, 370 nervous, vegetarian or lacto-vege- tarian diet in, 550 INDEX 597 Intestinal putrefaction restrained by koumiss, 142 Intestine, absorption of constituents of human milk in, 445 acclimatization of Bulgarian bacillus in, 558 antiseptic properties of milk in, 126 ' ballast, ' a stimulus to peristalsis of, 14. 168, 169, 251, 536 behaviour of human milk and cow's milk in, 453 digestion and absorption of food, 429-431 in, importance in infants, 445 in, of vegetables, 165, 166 (large), formation of fasces in, 431 power of absorbing food, 570-572 presence of one food in, affecting absorbability of other, 13 restraint of destruction of proteids in, 13 starch in, unfavourable to absorp- tion of proteid, 170 water absorbed solely by, 303 Intestines, diseases of, dietetic treat- ment, 533-537 Inulin in artichokes, 245 Iodine, 298 in fish, 298 in thyroid gland, 298 Irish, or Carraigeen, moss, 268 chemical composition, 268 Irish peasants, potato-belly of, 242 Iron in haemoglobin and derivatives ill-absorbed, 72, 292 in milk, in in yolk of egg, 154 proportion of, in different foods, 291-293 in relation to anaemia, 293 sources of, 288-290 Isinglass, purest form of gelatin, 76 Iso-lichenin in Iceland moss, 269 Italian pastes, 218 chemical composition, 219 Italian wines, 381 Jago on waste in bread-making, 199 Jam, 276 compared with butter, 136, 137, 477 • , • c proportion of cane-sugar in, 276 Japanese, low consumption of proteid among, 173 Jaundice, dietetic treatment, 538 fat forbidden in, 430 use of whey in, 133 Jaworski, digestibility of eggs, 157 Jellies, 76 Jessen, digestibility of beef and mutton compared, 67, 68 Jessop, exaggerated value of beef-tea, 107 exaggerated value of Liebig's Ex- tract, 94 Jobannis, natural mineral water, 309 Johnny-cakes, 224 chemical composition, 224 Johnston, banana flour, 256 losses in cooking, 404 record of tradition of stimulating action of coffee, 332 Junket, 114, 115 avoidance by diabetics, 115, 496 Kaisow tea, 315 Kanakas, the, method of slow-cooking, 411 Karrell, value of milk as food in disease, 130 Keller, phosphorus in food, 296 Kemmerich, analysis of Liebig's Extract, 92, 93 Kephir, 139. See also Koumiss chemical composition, 141 forbidden in diabetes, 496 Kephir grains, 139 Kernel of wheat. See Endosperm Kidney bean, 235 Kidney disease. See Renal disease Kidney-substance as article of food, 72 Kidney - substance as article of food, avoidance in gout, 72 Kitchener, Dr., effect of exercise on muscle-fibre, 59 non-belief in nutritive qualities of fungi, 267 Kjeldahl's process of analyzing nitrogen, 204 Klemperer, composition of malt -ex- tracts, 566 Koeppe value of natural mineral waters, 3" Kola, an ingredient of Vi-Cocoa, 336 KSnig, analyses of peptones, 565 composition of potted lobster, 86 composition of potted meats, 74 effects of cooking on meat, 64, 65 losses in cooking, 404 losses in cooking of yolk cf egg, 154 and Bomer, analysis 'of Liebig's Ex- tract, 93 Kops Ale, 371 Koumiss and kephir, 138, 139 absorption, 142 alcohol in, 141 chemical composition, 141 digestibility, 141 fermentation. 139, 140 forbidden in diabetes, 496 general therapeutic applications, 142, 143 59» FOOD AND DIETETICS Koumiss, nutritive qualities, 142 possesses diuretic properties, 142 production of lactic acid in, 140, 141 restrains intestinal putrefaction, 142 Kozai, Y., comparison between black and green tea, 314 Kronthal, natural mineral water, 309 Krueg, subcutaneous injection of oil, 578 Krummacher, proteid digestion, 415 waste of proteids in body, 415 notes Labourer, outdoor, thrives on vegetarian diet better than sedentary worker, 180 Labouring classes, diet of, suggested im- provement in, 56 in Dublin, diet of, 34 in Edinburgh, diet of. estimated by standard dietaries, 34 found to be insufficient, 56 in York, diet estimated by stan- dard dietaries, 34, 56 found to be insufficient, 56 Lactalbumin in milk, no, 116 Lactation, variations in human milk de- pendent on period of, 437, 438 Lactic acid in milk, 115 produced by sugar fermentation, 278, 279 production of, in Koumiss, 140, 141 Lactose, 274 least liable of all sugars to undergo fermentation, 279 See also Milk-sugar Lacto-vegetarian diet (purin-free bodies), 549. 55o therapeutic uses of 550 Lsevulose, or fruit-sugar, 274, 372 in diabetes, 498 in fruits, 254 Lak Cit, infant food, 468 Lancet Commission on chemical com- position of baking-powders, 200 Langworthy, composition of caviare, 85 composition of oysters, 86 of tinned lobster, 86 economic value of fish, 84 'greening ' of oysters, 88 ' La Nu Lofe,' 203 La Touche, C. D., diet of working-class families in Dublin, 34 Lavoisier, changes of food in body, 4 'Leaven,' or fermentation of bread by yeast, 196, 197 Lecithin, 296 proportion relatively greater in human than in cow's milk, 451 Legumin, 561 chief proteid in pulses, 231 Lehmann's humanized milk, 459 Lemco. See Liebig's Extract Lemco wine, 389 Lemonade, 308 made from fresh lemons, beneficial action in scurvy, 521 Lenhartz's method 9f dietetic treatment of gastric ulcer, 525 Lentil, 235 proteid in, 118 Leprosy due to fish diet, 83 Letheby, barley meal as food, 227 Leube, nutrient enemata, 573 relative digestibility of food, 427 subcutaneous injection of grape- sugar, 577 Leube-Rosenthal's Meat Solution, 102, 524 composition, 103 nutritive value high, 103 Lichenin in Iceland moss, 269 Lichens as food, 269. See also Iceland Moss Liebig, hock as beverage, 393 muscle food, 36 stimulating qualities of his extract, values of organic constituents of food, 2 Liebig's Extract, 61, 92 chemical composition, 92, 93 contains practically no proteid, 92, 95 gastric secretion powerfully ex- cited by, 95, 108, 418 stimulating qualities doubtful, 94.95 value depends on extractives, 93 Life impossible without proteid, 3 ' Lights. ' See Lung-substance Lime-juice, beneficial action in scurvy, 5 21 Lime-water, dilution of milk with, to aid digestibility, 120 Lipanin, 569 Liqueurs, 358, 360 Liquor Carnis, 100 Lithia water, 307 Liver, cirrhosis of, 143 dietetic treatment, 537, 557 koumiss useful in, 143 converts sugar into glycogen, 279, 280 diseases of, dietetic treatment, 537 Liver-substance as article of food, 72 avoidance in gout, 72, 510, 511 Loaf, colour and composition of, 201 Lobisch, effect of sleep on bodily fat, 42 sleep in relation to amount of food, 42 I Lobster as article of food, 85 INDEX 599 Luff, A. P., acids in wine 378, 393 value of somatose, 564 Lung-substance (' lights ') as article of food, 73 Lunin, mineral constituents in food, 290 'Lupa' Humanizer for use in modifica- tion of milk, 455 Macaroni, 218 Mace, 2S6 Macfadyen on reverse peristalsis, 572 Madeira, 378, 384 Magnesia water, 304 Magnesium, sources of, 291 Maine, University of, experiments on students as to dietetic value of milk, 129 Mairet and Florence, food required during mental labour, 41 Maize, 223 chemical composition, 224 economic value great, 226 nutritive value high, 226 See also Cerealine, Corn flakes, Corn- flour, Hominy, Maizena, Oswego, Popcorn, Samp, Sugar-corn Maize flour used to adulterate wheat- flour, 224 Maize meal, 224 Maizena, 225 chemical composition, 223 Malcolm, percentage composition of egg-yolk, 154 Malt, preparation of, 365 Malt-extracts, 566 addition to flour, 204 desiccated, 567 See also HofPs Malt-extract Malt-infusion.beneficial action in scurvy, Malt liquors, 364-371 action on digestion. 399 ale and beer, 364-371 composition of, 368 food value of, 310 Harvey's Sugar-free Ale, 371 in disease, 370 porter and stout, 367-369 Maltico, 468 Maltina Brown Bread, composition, 203 Maltina White Bread, composition, 203 Maltine in fever diet, 487 Malting of bread, 204 Maltose, 274 Maltova, 567 Malt whisky, 355 Malvern water. See Sparkling Malvern Maly, food and nutritive constituents, 16 Manhu Bread, composition, 203 Infant Food, 467, 470, 474 Maple-sugar, 271 chemical composition, 273 Mare's milk, 450 chemical composition, 141 Margarine, 135 chemical composition, 136 nutritive value, 138 nearly equals that of butter, 13? origin of, 135 Marggraf, the discoverer of beet-sugar, 272 Marmite, extract prepared from yeast, 97 Marsala, 385 Marvis, patent food derived from fish, 85 Mason's Strong Beef-tea, chemical com- position, 107 Masson, process for reducing water in vegetable foods, 164 Mastication of food, importance, 412 Mate. See Paraguay Tea Meals, amount at, 415 arrangement in diabetes, 499 in obesity, 505, 506 children's, 415 frequency of, 415 hours of, 415 relaxation after, 433 Meat, 58 acids in, 60 addition to bread, 215 avoidance at tea meal, 331 or restriction, in gout, 517 chemical composition, 61, 63 consumption, restricted among lower classes, 70 cooking of, 397-400 effect, 64 diet, appetizing qualities of, 181 energy engendered by, 174 digestibility, 67 and absorption, 65, 68 idiosyncrasy in, 68 retarded by cooking, 67 digestion, 66 diseased, harmless when cooked, 71 , economy ot, 70 effects of fattening on, 62 expensive as food, 70, 474 fat in, 59, 69 fibre, meat-extract preparations con- taining, 96 flavour, 60, 61 flavouring constituents, chiefly con- tained in soup, 90 frozen, 70 haemoglobin in, 60 increased amount in diet of phthisis recommended, 514 6oo FOOD AND DIETETICS Meat, lean, exclusive diet of, causing foetid stools, 430, 431 method of cooking, in Salisbury cure, 67 methods and effect of cooking, 397- 400 mineral substances in, 6i mixture with flour, 215 muscle fibre in, 60 myosin in, 60 not a perfect food, 69 nutritive value, 68 physical structure of, 58 potted, 74 proteids, 68 rabbits, and other small animals, ex- pensive forms of, 71 raw or underdone, easily digested, 67 recommended in phthisis, 514 waste matters, 62 water in, 62 loss of, due to cooking, 64 Meat-extractives, 61 most powerful excitants of gas- tric secretion, 418 not a food, 94 principally broken down pro- teid, 94 stimulate flow of gastric juice, 108 See also Beef-Extract, Liebig's Extract Meat-juice, fresh, beneficial action in scurvy, 522 Meat -juice press (Hercules Patent), 98 Meat-powders, 107, 109 Medicated wines, 388 Meigs's cream mixture for infants, 455 Mellin's Food, 468, 471 chemical composition, 471 Men, relative values for food require- ments at different ages, 45 Mendel, wine and digestion, 390 and Chittenden, absorption of alco- hol by the stomach, 339 analysis of Burton Pale Ale, 368 of Guinness's Dublin Stout, 368 Mental work, food required for, 41 Metabolism, 4 disorders of diet in, 488 influence of alcohol on, 344-349 of salt on, 294 of water on, 304 Metchnikoff, sour-milk treatment, 558 Micro-organisms in milk, 117 Midelton, egg - preparation as infant- food, 473 Milk, 110-131 . absorption, 123 Milk, absorption in intestine, 126 action of rennet on, in formation of cheese, 146 aeration, 121 and eggs, supplement to vegetarian diet, 176 and oatmeal, former staple diet of Scottish peasants, 174 and soda, why more digestible than plain milk, 121 ".-> antiseptic properties in intestine, 126 as diuretic, 129 as proteid-producer, 177 boiled, 122, 126 and unboiled, comparative ab- sorption, 125 avoidance in infantile scurvy, 5i5 boiling of, effect on composition, 116 calcium in, 291 casein in, no, 115, 451 characteristics in different animals, 448-452 chemical composition, no, 127 citric acid in, 112 clotting of, 114, 115, 120 in stomach, 119-120, 122, 453 coagulation, 114 condensed. See Condensed milk curdling distinguished from clotting, 115 desiccated, 119 analysis of, 119 diabetic, sugar-free, 498, 499 digestibility, 1 19-123 addition of citrate of soda to aid, 121 dilution with lime-water or barley-water to aid, 121 methods of improving, i;20, 122 relative, of boiled and unboiled, i2i, 124 dilution, 121 with alkalies, 121, 122 exercises antiseptic action on intes- tines, 126 fat in, in, 570 reliable gauge of quality, 114 feeding by bottle, average meals, 443 foods derived from, 132-145 foreign matter in, 117 human, absorption of constituents in intestine, 445 amount required daily, 442, 443 chemical differences between human and cow's, 450 choice of wet nurse, 439 clotting in stomach, density slight, 453 INDEX 601 Milk, human, compared with ass's milk, 449 composition, 463, 473 independent of outside in- fluences, 439 diet of, pure, 130 symptoms under, 131 digestibility, 445 of human and cow's milk compared, 452 extractives in, 437 fat in, 440, 446, 452 variable ingredient, 436 influence of illness on. 439 of motherland child'sindi- viduality, 433 of mother's diet on, 440, 44i lecithin in, proportion rela- tively greater than in cow s milk, 451 mineral salts in, compared with those in cow's, 452 nutritive value, 445-447 phosphorus in, 452 substitutes : condensed milk, 462-466 Fairchild's Peptogenic Milk-powder, 461 other animals' milk, 448- 460 partially peptonized milk, 461 preparations of cow's milk, 453-460 ■proprietary infant foods, 466-472 variations dependent on indi- vidual differences in mother or child, 439 dependent on period of suckling, 437-439 induced by irequent suck- ling, 441 humanized, 456-460 analysis of preparation, 456 chemically impossible, 452 intestinal antiseptic, 431 iron in, 111 lactalbumin in, no lactic acid in, 115. See also Bul- garian bacillus, Milk, soured, Sour-milk treatment micro-organisms in, 117 causing disease, 117 mineral matters in, in mixture with pea-soup. 233 not a fluid food, 114 not a perfect food, 127 nutritive value, 126 pasteurization, 118, 460 Milk, pathogenic bacteria in, 116-118 permanent preservation, 118, 119 proteids of, no, 128, 451 separated, 11 1 sterilization, 116, 118, 126, 460, 468 avoidance in infantile scurvy, 522 'sterilized,' absorbed as well as ordinary boiled milk, 126 soured, 143 sugar or lactose in, no carbohydrate constituent of milk, no time of duration in stomach, 122 transmission of disease by, 116, 117 use in acute renal disease, 541 in diabetes, 494 in fevers, 129, 483 in enemata, 573 in subacute nephritis, 542 value as food in disease, 123, 129, 130 water in, 112 See also Butter-milk, Cow's milk, Lacto-vegetarian diet, Skim-milk Milk-powders, peptogenic, 461 Milk-products, carbohydrates in, 493 Milk-somatose, 564 Milk-sugar, 568 dilution of milk with, 456 in fever diet, 483 Millet, 229 Indian, 229 chemical composition, 229 Milling wheat by roller, 192 germ of wheat removed by, 192 Mill-products, American, 194 chemical composition, 195 of wheat, 194 Milo Food, 467, 470 Milt as article of diet, 85 Mineral constituents of food, 288-299 daily amount required, 288, 289 function in building body, 289 in supplying energy, 288, 289 of food, in organic or in- organic combination, 289, 290 substances required, 288 Mineral matters in bread, 210 in cereals, 188 in child's diet, 477 in cow's milk, 452 in diet of infancy, 435 in fruits, 255 in meat, 61 m milk, -ill 602 FOOD AND DIETETICS Mineral matters in vegetable foods, 165, 250 in wholemeal bread, 214 Mineral salts in human and cow's milk compared, 452 Mineral waters, artificial. See Aerated waters natural, 309, 310 Adonis, 310 Apollinaris, 309 Contrexeville, 310 Johannis, 309 Krqnthal, 309 Perrier, 309 Rosbach, 309 St. Galmier, 310 Seltzer, 310 Sinaro, 310 Sparkling Malvern, 310 Vichy, 310 and artificial compared, 3". 312 uses of, 310 when to be avoided, 310 Mixed diet, necessity for, 30 feeders, problem of diet solved by, 176 Mock-turtle soup, 88 Moeller, incomplete absorption of bran, 210 merits of white and wholemeal bread , 211 Molasses, 274 Moleschott on ratio of proteid to carbo- hydrate and fat in childhood diet, 474 Moning tea, 315 Montgomerie's process for making ' Ber- maline bread,' 204 rusks, 476 Monti on use of whey for infants, 458 choice of wet nurse, 439 Moor on nutritive value of condensed milk, 464 and Pearmain, variability in com- position of milk, 113 Moore-Ede, Dr. (Dean of Worcester), apparatus for cheap cooking, 408 Moral degeneration from underfeeding, 57 Morris-Manges', Dr., typhoid fever diet, 487 Morris, Sir M., dietetic treatment of skin diseases, 548 Moseley's Food, 469, 471 Mosquera Beef-meal, 107 and sanose, 540 Mosso, experiments with sugar as a muscle-food, 282 Mostelle, 257 use in fevers, 257 Mother's diet, influence on human milk, 440, 446, 447 Mountaineering, value of sugar as muscle-food in, 284 Mouth, digestion in, 412 Muffler's Food, 467, 470 , Muggia, subcutaneous administration 01 yolk of egg, 578 Mulder, action of wine in healtn, 391 Miiller, subcutaneous injection of grape- sugar, 577 Munk, fat-forming power of foods, 512 Murchison, discussion on alcohol, 351 Murphy, C. J., value of maize as food, 226 Murray, use of spirits in disease, 362 Muscle-fibre, effect of exercise on, 59 in meat, 60 Muscle, nutritive requirements, 43 strength a property of, 174 Muscle-food, 36-38 alcohol as, 345 sugar as, 280-284 Muscular work, influence on diet, 37 Mush, 224 Mushrooms, 263-268 Mussels as food, 88 Mustard, 285 Mutton, digestibility, 67 Mutton-fat, irritating effect on stomach, 67 Myosin, 60 causes rigor mortis, 60 Nationalities, different, dietetic capaci- ties compared, 52 Neave's Food, 469-472 Nelson's Gelatine, 78 Nencki, reverse peristalsis, 572 Nephritis, accompanied by constipation, use of whey in, 133 acute, 541 use of milk in, 541 avoidance of spices in, 285 chronic, diet in, 543, 544 parenchymatous, salt-free diet in, 55° use of fluids in, 544 subacute, diet in, 542 average daily secretion of albu- min in, under different diets, 542 use of white meats in, 542 Nervous energy, large expenditure in digestion of bulky diet, 180 Nervous system, diseases of, dietetic means of slight value in treat- ment, 545 energy a property of, 174 influence in regulating tissue waste, 51 INDEX 603 Nestle's Milk, 465 in fever diet, 483 Neuralgia, idiopathic and gouty, vege- tarian or lacto- vegetarian diet in. 5 is 55o ' 3 3 ' Neurasthenia, complicating atonic dys- pepsia, Weir Mitchell treatment in. 533 fattening diet recommended for, 513, 515, 545 vegetarian or lacto-vegetarian diet in, 550 zomotherapy in, 556 Nevill's Bread, composition, 203 Wheatmeal Bread composition, 203 Nitrates, loss of, to soil, 183 Nitrogen, absorption diminished during mental work, 41 abundant in pulses, 231 amount required in food, 21 analysis by Kjeldahl process, 204 as source of muscle energy, 37 desirability of fixing free nitrogen in air, 183 food cycle, 182 in edible fungi, 266 in faeces, source of, 170 insufficient supply not incompatible with obesity, 54 Nitrogenous equilibrium, 21, 53 substances in cow's milk, 451 in vegetable foods, 163 Non-alcoholic beers, 371 grape wines, 390 Norwegian Self-acting Cooking Appar- atus, 407 Nuclein, 296 Nucleins of food, sources of exogenous uric acid, 516 Nucoline, commercial preparation of nuts, 260 Nursing home or hospital, treatment of diabetes should begin in, 501 Nurso Rusks, 476 Nut butter, commercial preparation of nuts, 260 Nutmeal, commercial preparation of nuts, 260 Nutmeg, 286 Nutricia, modification of cow's milk, 459 Nutrient enemata. See Rectal feeding suppositories, 576 Nutrition, function of, regulated by central nervous system, 51 impaired, use of koumiss in cases of, 143 Nutritive constituents of food, 2 amounts required daily, 28 Nutritive value of almonds, 262 of arrowroot, sago, tapioca, 247 Nutritive value of banana flour, 258 of beef-tea exaggerated, 106 of bread, 214-216 of casein preparations, 144 of cheese, 149 of cocoa-nuts, 261 of eggs, 158 of fat in vegetable foods, 171 of figs, 259 of fruits, 256, 257 of fungi exaggerated, 267 of gelatin, 77 of green vegetables, low, 251 of maize, high, 226 of meat, 68 of milk, 126 condensed, 464 human, 445-447 of nuts, 261 of oats, 220 of oysters diminished by fatten- ing, 88 not high, 87 of potatoes, 239, 240 of pulses high, 233 of starch, 171 of sugar, 171, 281 of turnip, not high, 244 of vegetable foods, 171 Nutrose, peanut an ingredient of, 236 Nuts, 259 absorbability, 261 chemical composition, 259, 260, 262 commercial preparations, 260. See also under various names digestibility, 260 malted, 260 chemical composition, 261 nutritive value, 261 substitutes for butter prepared from, 260 Nuttolene, commercial preparation of nuts, 260 Nuttose, commercial preparation of nuts, 260 Oarsmen, training of, value of sugar diet in, 283 Oatmeal, 174, 221 and milk, former staple diet of Scottish peasants, 174 avoidance in gout, 221, 551 purin bodies (uric acid formers) contained in, 221 unfitted for bread-making, 222 value in rickets, 523 Oats, 220 absorbability, 223 most nutritious of all cereals, 220, 223 604 FOOD AND DIETETICS Oats, preparations of, chemical composi- tion, 222 rolling of, 221 See also Avenine, Berina, (Mont- gomerie's), ' Carr's Oaten,' ' Creamota,' 'Plasmon Oatmeal,' 'Provost Oats,' 'Quaker Oats,' ' Veda Oatmeal,' 'Waverley Oats ' Obesity aggravated in women of lux- urious life, 48 not incompatible with insufficient nitrogenous nutrition, 54 diet, 502.512 alcohol in, 370, 371,506 arrangement of meals, 509 Banting diet, 504 beverages, 370, 371, 511 chemical substitutes for sugar used in, 287 dietaries, 504 509 relative value of, 508 reduction of Calories, 503, 504 of food, 503, 504 of fluid, 509, 510 starvation method needs caution, 508 vegetarian and lacto- vegetarian, 55° Oenanthine, 379 Oertel's diet for obesity, 506 Offal as food, 71 comparative absorption, 74 composition of, 71 nutritive value of, 72 of fish. See Caviare, Milt, Roe Ogata, effect of tea on digestion, 330 experiments on digestibility of sugar, 278 influence of salt on digestion, 294 Oil, subcutaneous injection, 577 Old age, dietetic requirements, 46 ( temperance in, 46 Oleomargarine. See Margarine Olive oil, subcutaneous injection, 577 Onions, 245 avoidance in gout, 551 rich in cellulose, 245 uric acid-forming bodies in, 252, 55i valuable in constipation, 245 Oolong tea, 316 Ophthalmia, epidemic, and underfeed- ing. 55 Opmus Bread, composition, 203 Orangeade, 308 Osmazone, production on surface of roast meat, 399 Oswego, preparation of maize, 225 Ovalbumin, 151 Ovaltine, 336 Oven for cheap cooking, 408 Over-feeding, 52 injurious effect of, 53 Ovomucin, 151 Ovomucoid, 151 Oxalic acid; foods rich in, avoidance in oxaluria, 521 in rhubarb, 252 in various foods, 297 source of, 297 Oxaluria, dietetic treatment, 521 so-called, variety of acid dyspepsia, 298 Ox-serum, rectal enemata of, 575, 576 Oyster as article of food, 86 digestibility easy when raw, 87 fattening diminishes nutritive value, 88 glycogen in, 86 ' greening ' of, 87 nutritive value not high. 87 transmission of typhoid fever by, 87 methods of avoidance, 87 unsuitability in diabetes, 86, 87 Pabst, use of white meats in nephritis, 542 Paget, Sir J., discussion on alcohol, 351 Paget's Perfected Milk Food, 456 Pancreas-substance as food, value of, 73 Pancreatic digestion, reserve power of, 429. 430 emulsion, 569 juice, digestion of fat by, 429 secretion of, stimulants, 429 Paracasein, 120 hydrochloride, 120 Paraguay tea, 336 Paris, use of horseflesh as human food in, 70 Parkes, consumption of alcohol, 348 and Wollowicz, effects of alcohol on the circulation, 341 Parkinson, alcohol and immunity, 351 Parsnips, 245 Pasteurization of milk, 118, 460 of wine. 372 Paton, Noel, muscle food, 37 diet of labouring classes in Edin- burgh, 34 Pavy, F. W., F.R.S., digestibility of fish, 82 Pawlow, I. P., digestibility of milk, 123 excitants of appetite, 416 experiments on action of condiments and spices, 285 meat extracts and gastric secretion, 95 salivary digestion, 413 secretion of gastric juice, 416, 417, 418 INDEX 605 Payen on composition of parts of lobster and crab, 85 Peanut, 236 diabetic food, 236 ■ Nutrose ' largely compounded of, 236 Pearmain on value of condensed milk , 463 and Moor, variability in composi- tion of milk, 113 Pea-soup, 233 mixture with milk, 233 Peas, garden, 235 Peasmeal, mixture with flour, 215 Pectins, 163 Pectose in turnips, 244 in vegetable foods, 163 Pegnin, 455 Pekoe tea, 314 Pemmican, 108, 561 Pentose in fruits, 255 Pentosuria, production of, 280 Penzoldt, digestibility of eggs, 157 digestibility of fish, 82 relative digestibility of foods, 424- 426 time of appearance of free acid in stomach, 420 Pepper, black, 285 white, 285 Pepsin wines, 338 Peptogenic milk powder, 461 Peptones, 562-566 chemical composition, 565 diarrhoea caused by, 563 incapable of exciting gastric secre- tions, 418 influence on digestion, 562 on secretion of gastric juice and on appetite, 563 Peptonized food, home-made, 566 Peptonoids. See Carnrick's Peptonoids Pereira, non-belief in nutritive qualities of fungi, 267 potatoes as food, 241 salivary digestion of moist foods, 413 Peristalsis of intestine, stimulus supplied by ballast, 14, 168, 169, 251 of intestine, reverse, 572 of stomach, 338, 417 Periwinkles as food, 88 Perrier, natural mineral water, 309 Perry, 387 Personal peculiarity, influence on amount of food, 51 Petroleum, non-absorbability of, 16 Phosphates, 295, 296 Phospho-carnic acid, 296 Phosphoric acid, absorption diminished during mental work, 41 absorption of, how lessened, 430 percentage in fresh foods, 295 Phosphorus contained in casein, 144 fish not rich in, 83 function and sources, 295, 296 in food, 296 in human milk, 452 in yolk of egg, 154 not necessary as brain food, 41 percentage in fresh foods, 295 Phthisis, increased supply of proteid in diet for, 514 fat in diet for, 513, 514 koumiss in diet for, 142, 143 meat diet for, 514 Physical tests of value of food, 4 Physiological effects of alcohol, 337- 349 method for construction of standard of dietaries, 25 requirements in infant's diet, 432 tests of value of food, 8 Phytin, 296 Plantose, 561, 562 Plants synthetical feeders, 184 Plasmon, addition to milk in fever diet, 483. 487 casein preparation, 143, 144, 561 home-made diabetic bread prepared from, 497 nutritive value, 335 with lacto-vegetarian diet, 511 Plasmon Chocolate, 328 Plasmon Cocoa, 335 Plasmon Diabetic Biscuits, 497 Plasmon Oatmeal, 222 P;asmon Tea, 331 ' detannation ' of infusion through casein in, 331 Plastering of wine, 383 Playfair on standard dietaries, 33 standards of number of Calories to be supplied for work of different degrees of severity, 36 Pliny, plastering of wine mentioned by, 383 Plombieres' method of treatment of muco-membranous colitis at, 534 Poisonous properties of fungi, 263 Pollyta, 469 Pone, preparation of maize, 224 Pop-corn, chemical composition, 225 variety of maize, 225 Popoff on digestibilty of fish, 81 on digestion of meat, 66 Porcherine, chemical substitute for sugar, 287 Pork digestibility, 68 Porridge, 222 absorbability of, 223 and milk meal, superior to tea and bread and butter meal, 223 6o6 FOOD AND DIETETICS Port, 373, 384 nutrient, 389 Porter, 367 Postnikoff, nutritive qualities of koumiss, 142 Potash in vegetable foods, 165 bicarbonate of, combination with casein of cheese, to promote digestibility, 149 salts of, depressant effect on pulse not exercised by, 94 in potatoes, 239 Potash water, 304 Potato-belly of Irish peasants, 242 Potatoes, 237 absorbability, 16, 239 avoidance in dilatation of stomach, 239 beneficial action in scurvy, 236 bulkiness of, 242 chemical composition, 238, 241 asparagin in, 242 richness in starch, 239 cooking of, 239, 240, 401, 402 digestibility, 241, 242 economic value, 242 nutritive value, 239, 240 salts of potash in, 239 See also Sweet potato, Yam Potted meat, 74 Poultry, composition of, 63 Pozziale, incomplete absorption of bran, 210 Prausnitz, absorption of milk, 125 composition of faeces, 431 foods as faeces producers, 10 Prautner and Stowasser, experiments with sugar as a muscle food, 283 Predigested foods, 562-566 Priestiey, Joseph, inventor of artificial aerated water, 306 Prison diets, data as to absorption of proteid derived from, 170 in Scotland, 34 Prolacto Bread in diabetes, 497 Proof Spirit, 353 Proprietary infant foods. See Infant foods Proteid absorption of, 11, 13 by large intestine, 570, 571 defective, in bread, 209 in wholemeal bread, 211 amount required daily, 20, 176 in diet for training, 38, 39 in mental strain, 39 in muscular work, 44 and fat essential compounds of cheese, 147 broken-down, meat extractives prin- cipally consist of, 94 Proteid, bulk and weight of foods yielding same quantity, 177, 178 butter-milk cheap source of, 138 coagulable, in beef -juices, 99, 108 constant supply of, necessary, 175, 409 deficient in rice, 229 degree of concentration possible, 536 diet, exclusive. See Salisbury cure effect of heat on, 396, 404 foods, artificial, 561-566 high percentage in casein prepara- tions, 144 in bread, methods of increasing, 215 in casein, 144 in cereals, 187 in cheese, 147 in diabetes diet, 491 in lentils, 178 in Liebig's Extract, amount very slight, 93, 95, 96 in meat, 68 in milk, no, 128, 451 in pulses, 231 in rectal feeding, 570, 571 in subcutaneous feeding, 576 in vegetable foods, deficiency of, 172, 185 difficult to absorb, i6g, 170, 173 increase of, in diet for muscular work, 37, 41 in diet of phthisis, 574 increases power of resisting disease, 175 insufficient, leads to imperfect tissue repair, 54 lack of, in food, injuriousness of, 54 life impossible without, 3 minimum of, in purely vegetable diet, 185 amount required for healthy maintenance of lile, 173, 176 consumption, 173 necessity in diet of growing chil- dren, 175 preponderance in animal food, 172 producers of, eggs and milk as, 176 ratio of, to carbohydrate and fat in child's diet, 474 relative absorption in various foods, 169 relative cost per pound in different forms, 181 skim-milk cheap source of, 128 sources of, in child's diet, 475 sparers, 23, 53, 346 gelatin as, 77 INDEX 607 Proteld sparers, sugar as, 281, 282 stimulating effects on cells, 69 supplies energy, 174 vegetable, 163, 171 Proteids, destruction by putrefaction, 43° , oxidation under purin - free diet, Hare's system and Salisbury cure, 555 restraint of destruction in intestine, 13 time of stay in stomach, 425 waste of, in body, 414, 415 Protene, 143 diabetic bread, 497 flour, preparation of casein, 143, 561 home-made diabetic bread, prepared from, 497 Protoplasm poisoned by alcohol, 344, 345 Proust, first to recognize refreshing properties of extract of meat, 95 Prout, on oxalic acid and oxalic cal- culus, 298 Provost Oats, 221, 222 Pruritus, dietetic treatment, 547 Psoriasis, dietetic treatment, 547 Salisbury cure in treatment of, 553 Ptyalin, 413 carbohydrates in, 493 Pulse not depressed by potash salts, 94 Pulses, 231 absorption, 232, 233 avoidance in gout. 551 chemical composition, 231, 234 legumin chief proteid, 231 rich in carbohydrates, poor in fat, 232 rich in nitrogen, 231 digestibility, 232 nutritive value high, 233 purin bodies contained in, 232 tend to produce flatulence, 231 See also Beans, Peas, Lentil Pumpernickel (black bread), 197 wasteful food, 228 Puralis, aerated distilled water, 307 Purin bodies (uric acid formers), 516 asparagus, 551 cocoa, 551 coffee, 551 meat, 551 oatmeal, 221, 551 onions, 252, 551 pulses, 232, 551 sweetbread, 551 tea, 551 Purin-free diet, 517, 550, 552 foods rich in, poor in, or free from, 551 Purin-free diet, In epilepsy, 545 oxidation of proteids under, Putrefaction, intestinal, restrained by koumiss, 142 by carbohydrates, 430 by milk, 431 Pylorus, length of time between first swallowing of food and opening of, 423 Quaker Oats, 221, 222 Rabbits, expensive form of meat, 71 Raisins, 259 Ranke on body-weight and food in rela- tion to season, 50 waste of proteids in body, 515 Ransome, dietary for muco-membranous colitis, 535 Raw-beef juice, 98, 99 composition, 99 egg-white as substitute for, 102 methods of preparation, 98, 99 Raw meat or raw meat-juice, treatment See Zomotherapy Raw meat-juice as infant food, 473 Rectal feeding, 54, 570-576 formula for, 574, 575 general technique, 575 importance of common salt in, 572 nutrient suppositories, 576 reverse peristalsis in, 572 ' Reed ' Humanizer for use in modifica- tion of milk, 455 Reichmann on digestibility of milk, 122 time of duration of milk in stomach, 123 Reinach on serum for subcutaneous feeding, 576 Relapsing fever and underfeeding, 51 dietetic treatment, 540 use of milk in, 129 Renal disease in relation to alcohol, 348 use of koumiss in, 143 Rennet in formation of cheese, 146 and rennin, 114 Rennin, 114 clots milk in stomach, 120 Rest cure, 515 excretion of carbonic acid during, 42 Rest, influence of, on digestion, 433 on amount of food , 42 Retzius on the prepyloric sphincter, 422 Revalenta Arabica, 235 chemical composition, 235 6o8 FOOD AND DIETETICS Reyher, composition of human milk be- fore and after lactation, 438 Rheumatic fever, diet, 486 Rhubarb, avoidance in cases of gravel, 202 oxalic acid in, 252 Rice, 228 absorption, 229 chemical composition, 228 digestibility, 229 nutritive value low, 229 Richet, C, introduction of zomotherapy, 556 Richmond, Droop, fat in cream, 133 Rickets, 522 avoidance of starchy foods in, 522 increase of fattening diet, 522 value of yolk of egg in diet of, 522 Riegel's enema, 574 Rigor mortis caused by myosin, 60 Ringer, diabetic milk, 495 Roasting, 399 Robb's Nursery Biscuits, 476 Roberts, Sir W., effect of coffee and tea on digestion, 329, 330 on uric acid, 520 substitution of peptones for ordinary proteids, 562 wine and salivary digestion, 390 Robertson, Aitchison, effect of tea on digestion, 329 experiments on digestibility of sugar, 277, 278 fermentation of sugar, 278, 279 proportion of cane-sugar in home- made jams, 276 wine and salivary digestion, 390 Robinson's Groats, 469, 472 Patent Barley, 227, 469, 472 Roborat, 220, 561 home-made diabetic bread prepared from, 497 Roe as article of diet, 85. See also Caviare, Milt Rolling of oats, 220 Romberg on digestibility of rye-bread, 213 Roots and tubers, 236, 247 carbohydrates in, 493 chemical composition, 237 Rosacea, dietetic treatment, 547 Rosbach, natural mineral water, 309 Rosenfeld, nutritive value of fish, 83 Rotch, modification of cow's milk for infants, 459 Rotch's cream mixture for infants, 455 Rowing, dietary required for, 40 value of sugar-diet in training for, 283 Rowntree, diet of poorer sections of community in York, 34, 56 Rubner, absorbability of different foods, 10 absorption and waste of green vegetables, 251 absorption of mixed diet, 14 of proteids of wholemeal bread, 211 amounts of proteid required by per- sons of different weight, 43, 44 combustion in body, 4, 5 fat-forming power of foods, 502 incomplete absorption of bran, 210 potatoes as food, 241 standard of Calories for work of different severity, 35 supply of proteid, 29 wholemeal bread, 212, 213, 214 Rum, 358 Rusks, 207 Bipsine, Montgomerie, Nurso, Robb's, 476 Rye, 228 digestibility, 228 Rye bread, digestibility, 213 Saccharomyces mycoderma in kephir grains, 139 Saccharin, chemical substitute for sugar, 287 Sago, 246 chemical composition, 246 digestibility, 246 economic value, 247 nutritive value, 247 St. Galmier, natural mineral water, 310 St. Martin, Alexis, visible observations on his digestion of food, 433 Salep, 246 Salisbury cure, 67. 69, 553 in chronic articular gout, 553 in psoriasis, 553 in sprue, 534, 553 method of preparing diet, 554 oxidation of proteids in, 555 Saliva, uses of, 412, 413 Salivary digestion, 412, 413 action of alcohol on, 338 effect of wine on, 390 Salmon, nutritive value high, 84 Salt, Cerebos, 293 common,, function and sources, 293- 295 salt-craving, 294, 295 use in rectal feeding, 572 Salt-free diet, 556 construction of, 556, 557 indications for, 557 Saltet, chemical composition of French mushrooms, 265 Salutaris, aerated distilled water, 307 Samp, preparation of maize, 225 INDEX 609 Samuel, fusel-oil, 363 Sanatogen, 145 preparation of casein, 145, 561 rectal absorption of, 571 Sandow's diet for training, 39, 40 Sanitas Health Cocoa, 335 Sanitas Nut Food Company, prepara- tions of, 260 Sardines in oil, chemical composition, 88 Sauerkraut, beneficial action in scurvy, 521 Sausages, composition, 75 value as food, 75 Savages, symptoms of intoxication pro- duced by use of meat by, 69 Savory and Moore's Food, 468, 471 Saxin , chemical substitute for sugar, 287 Scallops as food, 88 Scarlet runner, 235 Schloss on diet in epilepsy, 545 Schmid-Monnard, average meals of bottle-fed babies, 443 Schiile, digestibility of sugar, 278 gastric secretion, 416 Schultz-Schultzenstein, effect of tea on digestion, 330 Schumberg, experiments with sugar as a muscle food, 283 Schuster, absorption of proteid, 170 Schwenkenbecher, energy value of foods, 8 Schweppe's Seltzer, 307 Scotch bread, ' barm ' used for fermen- tation of, 198 Scotland, prison diets in, estimated by standard dietaries, 34 Scott's Oat Flour, 469 Scottish peasants, diet of, 174 Scurvy, 514 beneficial action on, of lemonade, 521 lime-juice, 521 malt infusion, 521 meat-juice (fresh), 522 potatoes, 236 Sauerkraut, 521 development of, 299 infantile, boiled or sterilized milk to be avoided in, 522 dietetic treatment, 522 prevented by cabbage diet, 252 fruit diet, 255 Season, in relation to body-weight and amount of food required, 50 Seatree's Bread composition, 203 Sedentary worker thrives less than out- door labourer on vegetable diet, 180 Seltzer, natural mineral water, 310 Seltzer-water, substitute for natural product, 307 Semolina, 218 Serum in subcutaneous feeding, 576. See also Ox-serum Sesame oil, subcutaneous injection, 577 Sex, influence on amount of food, 46 Sherry, 373, 382 Ship's biscuit, 196 Shredded wheat, 220 Sieber, Dr., composition of honey, 275 reverse peristalsis, 572 Silent spirit, 354, 358 Silica, 298 Sinaro, natural mineral water, 310 Skim-milk, 111 cheap source of proteid, 128 in diabetes, 494, 495 mixture with bread, 128 with flour, 215 Skin diseases, dietetic treatment of, 546, 548 rigidity contraindicated, 548 vegetarian, or lacto-vege- tarian, 550 Sleep, effect on bodily fat, 42 influence on amount of food, 42 Sloane, Sir Hans, on the green turtle, 88 Smith, amounts of fat consumed under different conditions, 43 nutritive value of herring, 84 selection of different kinds ot food, 69 use of fat in phthisis, 514 Smith's patent for retention of germ of wheat, 195 Soda-water, 807 medicinal, 307 Sodium, sources and function, 292-295 chloride. See Salt, common Soil, loss of nitrates to, 183 Sole, nutritive value of haddock same as that of, 17, 84 Somatose, 108, 563, 564 in fever diet, 487 addition to milk in, 483 See also Milk-somatose Souchong tea, 314 Soup, mock-turtle, 88 turtle, 88 Soups, 90 clear, promote flow of gastric juice, 91. 4'9 nutritivt qualities small, 90 vehicle for introduction of other food materials into stomach, 91 Sour-milk treatment, 557, 558 indications and contra- indications for, 558. See also Bulgarian bacillus Soxhlet's Apparatus for Milk Steriliza- tion, 1:8 preparation of cow's milk for in- fants, 455 Soy bean, 235 39 6io FOOD AND DIETETICS Sparklets process, 121, 305 Sparkling Malvern, natural mineral water, 310 Sparks, milk diet in subacute nephritis, 543 use of milk in nephritis, 543 Spermaceti, 569, 570 Sphincter, pre-pyloric functions of, 422, 423 Spices and condiments, 284 action on secretion of gastric juice variable and inconstant, 285 avoidance in nephritis, 285 necessity for, 284 Spirit, proof, 353 silent, 351, 358 Spirits, >353-3 6 4 action on digestion, 361 on body, 361-363 addition of to infected water does not destroy micro-organisms, 306 comparative composition of , 359, 360 ' Sponge ' formation in bread-making, 198 Sprue, dietetic treatment, 534, 553 Stafford, T. T., diet of working-class families in Dublin, 34 Starch, abundant in potatoes, 239 digestion of, 169 in stomach, 420 digestibility by infants, 472 effect of heat on, 391, 397, 400 gelatinization-point of, 396 incapable of exciting gastric secre- tion, 418 in vegetable foods, 161 nutritive value, 171 presence in intestine unfavourable to absorption of proteid, 170 rectal absorption of, 571 Starchy foods, avoidance in diet of rickets, 516 Starvation diets, 30 in obesity, 508 Steinitzer, value of sugar as muscle food in Alpine climbing, 284 Sterilization of milk, 116, 118, 126, 460 of water, 306 Stevenson, value of somatose, 564 Stewing of meat, 400 Stimulant, definition of, 340 alcohol as, 340-344 caffeine in tea and coffee as, 332, 333 Liebig's Extract as, 94 Stirabout, 224 Stockman, iron in milk, in, 112 iron in food, 291, 292 Stomach, absorption of alcohol by, 339, 340 absorptive power of, 428 acidity of contents, 419 relative to morbid gastric sensations, 421 Stomach, chronic catarrh, use of koumiss in, 143 clotting of milk in, 119-122, 453 digestion in, 413 in infants slight, 445 of food introduced without subject's knowledge, 417 of starch in, 420 of vegetables, 165 dilatation of, avoidance of potatoes in, 239 obstructive and non-obstructive (atonic), diet in, 528-530 disorders of, diet in, 523 distension from bulky diet, 179 distinction of cardiac from pyloric end, 422 duration of food in, 422, 423 effect of alcohol on, 338-340 escape of water from, 303 functions of, 414 hydrochloric acid in, 420 irritating effect of mutton fat on, 67 local injury to, caused by extremes of temperature in foods, 428 longer duration of bulky foods in, 9 movements of, peristaltic, 338, 422, 423 pre-pyloric sphincter of, function, 422 rest of stomach, aim in dietetic treatment of gastric ulcer, 524 secretion of gastric juice in, 416-419 time of duration of milk in, 122 visible observations in case of Alexis St. Martin, 433 water not absorbed by, 303 See also Dyspepsia, Gastric ulcer. Gastritis Stout, 364, 367 as soporific, 370 Stowasser and Prautner, experiments with sugar as a muscle food, 283 Strasser, use of milk in diabetes, 494 Strawberries, control of diarrhoea of sprue by, 534 Strength, property of muscles, 174 sustained, and sudden energy, factors severally producing, 174, 175 Students at Edinburgh, dietary. 34 Stutzer on digestion of meat, 66 on nutritive value of oyster, 87 Subbotin and Verdeil, iron in food, 293 Subcutaneous feeding, 576-578 Suckling, frequent, influence on compo- sition of human milk, 441. See also Lactation Sucroses, the, 270 Sugar, 270 assimilation, 279 INDEX 6n Sugar, beetroot rich in, 244 carrots rich in, 244 chemical substitutes for, 287 use in diabetes, gout, and obesity, 287 conversion into caramel, 397 into glycogen by liver, 279, 280 dangers of excessive use of, 282 digestibility, 169, 277-279 diluted, greater digestibility of, 278 economic value, 281 effect of, on teeth, 279, 476, 477 favourable influence on health and growth of children, 282 fermentation of different classes of, 278 alcoholic, 278, 279 butyric, 278, 279 lactic, 278, 279 incapable of exciting gastric secre- tion, 418 in child's diet, 476 increased consumption of, in rela- tion to increased prevalence of diabetes, 282 in fever diet, 483 in fruits, 254 in vegetable foods, 161, 163 in wine, 378 action of, 393 invert, 275 greater digestibility, 278 irritant to tissues in strong solution, 277, 278 muscle food, 282, 283 in mountaineering, 284 in training, 283 nutritive value, 171, 281 proteid-sparer, 281,282 rectal absorption of, 571 See also Beet-sugar, Cane-sugar, Milk-sugar Sugar-candy, 275 Sugar-corn, variety of maize, 226 Sugar-free ale, 371 milk for diabetics, 495, 496 Sulphur in food, 298 beans rich in, 231, 232, 235 * Surfeit,' death from, 53 Sweetbread, 73 avoidance in gout, 73, 551 organs included under term, 73 rapid digestion, 425 value as food, 73 Sweetmeats, 275 colouring matter, 276 Sweet potato, 243 Swientochowski, action of alcohol on heart and circulation, 342 Sydenham, choice of food for patients, 480 Tankard, effects of cooking on meat, 65 Tannin, analysis of Carnrick's pepto- noids, 564 of somatose, 563 how to neutralize effect, 331 in cocoa, 327 in tea, 315, 317-320, 330, 331 in wine, 343, 374, 377, 393 Tapioca, 245 digestibility, 246 economic value, 247 nutritive value, 247 Tartaric acid in wine, 372, 377 Taurine, 101 Tea, 312322 and bread-and-butter meal con- trasted with porridge and milk meal, 223 allowed in diabetes, 498 avoidance in atonic or flatulent dyspepsia, 532 in cases of gout, 335, 551 black, 314, 315 caffeine in, 317-320 Ceylon teas, 314 chemical composition, 315-318 of infusion, 318-320 Chinese teas, 315, 316 duration of stay in stomach, 327 green, 315, 316 history of, 313 Indian teas, 315, 316 influence of tannic acid in, 315, 317- 320, 330, 331 of time on infusion, 321 on salivary and gastric diges- tion, 329-335 infusion of, 320, 321 injurious effects, 331, 335 judging of, 316 (meal), 'high ' and ' meat ' teas, 331 mode of manufacture, 313-315 not a food, 334 Plasmon tea, 331 proper method of making, 320 stimulating action, 333, 334 varieties of, 314-317 volatile oil in, 334 Tea-tasters, 321, 334 Tebb, W. Scott, analysis of tea, 317 Teeth, effect of sugar on, 279, 476, 477 effect of temperature of foods and drinks on, 428 Temperance in old age, 46 Temperature of body, influence of alco- hol on, 342, 345 maintenance of, 44 of food and drinks, 427 extreme, local effect of, 428 necessary for quenching thirst, 428 6l2 FOOD AND DIETETICS Tests of value of food, chemical, 4 economic, 16 physical, 4 calorie standard, 4 physiological, 8 Thackeray on stimulating effect of wine 342 Theinhardt's Soluble Infant Food, 46S Theobromine in cocoa. 327 source of uric acid, 335 Therapeutics, limitations of diet in, 479 Thin subjects, large amount of lood required by, explanation, 44 Thirst quenched by milk in febrile diseases. 129 temperature for quenching, 428 See also Tissue-thirst Thompson, Sir Henry, cooking of fish, 400 gravel dietetics, 520 Thomson, Dr. Dundas, on waste in bread- making, 199 Thudichum, Dr., action of wine in health, 391 on champagne, 386 on claret, 381 on plastering of wines, 383 Thymus gland, value as food, 73 Thyroid gland, iodine in, 298 Tissue-formers, 3 Tissue-repair imperfect under insufficient supply of proteid, 54 Tissue- thirst, how produced, 303 Tissue-waste under influence of nervous system, 51 Toadstools, 263 Toast to be avoided in diabetic diet, 497 Toffee, 273 as fat food, 275, 570 Tomatoes, citric acid in, 252, 298 Tortilla, 224 Tournier's enema, 574 Tous les mois, 246 Training, definition, 38 diet of, 38 Sandow's, 39, 40 sugar as muscle food in. 284 See also Athletes Treacle, 274, 567 Triagon bread (O'Callaghan's) composi- tion, 203 Tripe, value as food, 73 Triticumina Bread, composition, 203 Tropics, consumption of food in, less than in temperate zone, 49 Tropon, 562 Tubercle bacilli, presence in cow's milk, 117 Tuberculosis, abstinence from fat and liability to, 418 Tuberculosis and underfeeding, 55 conveyed by milk, 117 diet in, 513, 514 rarity among asses, 450 zomotherapy in, 556 Tubers and roots, 231-247 TuffnelPs diet for aneurysm, 540 Tunnicliffe, F. W., phosphorus in food,, 296 and Sir Lauder Brunton, researches on digestibility of bread, 213 Turkey, composition of flesh of, 63 Turner, W. Aldren, purin-free diet in epilepsy. 545 Turnips, 243 allowed in diabetes, 244 nutritive value not high, 244 ' pectose ' bodies in, 244 Turog Bread, 205 Turtle, green, as food, 88 Turtle soup, 88 Typhoid fever conveyed by milk, 117 diet in, 486-488 liberal, 487 oysters as means of conveying infection of, 87 method of avoidance of risk, 87 use of whey in, 133 Typhus fever and underfeeding, 55 Uffelmann, digestion of meat, 66 effect of temperature of food on teeth, 428 Underfeeding, 53, 54 and epidemic ophthalmia, 55 and tuberculosis, 55 and typhus and relapsing fever, 55 bad effects, worse in childhood, 55 diminishes power of digestion, 57 resistance to cold, 55 moral degeneration due to, 57 more injurious than overfeeding, 54 Uric acid, amount liberated in body controlled by lacto- vegetarian diet (purin-free bodies), 516, 517 avoidance of foods and beverages yielding, 516, 517 caffeine, source of, 335 diminution of amount in urine, 519, 520 endogenous and exogenous, 516 formers. See Purin bodies gravel, use of whey in, 133 increase of solubility in urine, 519, 520 sources of, 335, 517 Urticaria, dietetic treatment, 547 INDEX 613 Vagos Bread, 203 Valentine's Meat-Juice, 100 Valsalva on diet for aneurysm, 540 Van Slyke, analysis of milk, 112 digestion of casein, 120 Veal, digestibility, 67, 68 Veda, malted bread, 203 Veda Oatmeal, 222 Vegetable foods. 160-186 absorption, 165, 166 obstacles, 167 proteids difficult to absorb, 169-170, 173 bulkiness, 15, 164, 166, 178 physiological disadvan- tages, 15, 179, 180 chemical constituents, 160-165 carbohydrates, 161 cellulose, 161, 162 dextrin, 162 extractives, 164 fats, 164, 169, 171 mineral constituents, 165 nitrogenous substances, 163 pectose, 163 potash, 165 starch, 161 sugar, 161 water, 164 cooked, chemical composition, 406 cooking of, 401 methods and effect, 401 digestibility, 165, 166 obstacles, 167 economic value, 181 relative, 184 low resistance to disease under vegetable diet, 180 nutritive value, 171 of fat in, 171 proteid, 163 rate of digestion, 425 wateriness, disadvantage in, 164, 180 and animal foods, relative absorp- tion, 166 mixed, and animal diets, relative bulks, 167 Vegetables, green, 248 absorption, 252 chemical composition, 248, 249 carbohydrates, 250, 493 digestibility difficult, 251 eczema caused by deficiency of, 252 effect of cooking on, 248 fat deficient in, 251 mineral salts abundant, 165, 252 nutritive value low, 251 See also Vegox Vegetarianism, 172-186, 549, 550 arguments for, 172 eggs and milk a supplement to vege- tarian diet, 176 in treatment of headaches, 546 proteid-minimum a condition of, 185 succeeds better with outdoor la- bourers than sedentary workers, 42, 180 therapeutic uses of, 549 . 550 Vegsu (or vegetable suet), commercial preparation of nuts, 260 Verdeil and Subbotin, iron in food, 293 Verhaegen, relative digestibility of foods, 420 time of duration of milk in stomach, 123 Vermicelli, 218 Vichy, natural mineral water, 310 Vi-Cocoa, 336 Vienna Bread, 204 Vieth, fat in cream, 133 Vigier, use of whey for infants, 458 Vinegar, 286 Vin Regno, 389 Virol, 569 Voit, amount of proteid required daily, 176 comparative absorption of offal, 74 composition of a dinner meal, 415 composition of Bovril, 96, 97 influence of diet on demand for water, 300 meat extractives, 95 ratio of proteids to carbohydrate and fat in childhood diet, 474 subcutaneous injection of grape- sugar, 577 results ' of observations on vege- tarians, 179 Volatile acids in wine, 378 oil in tea, 334 Vomiting, value of koumiss in attacks of, 143 Von Bibra, staleness of bread, 205, 206 Von Dungern, method of rendering casein in milk digestible, 455 Von Noorden on appetite, 417 danger of alcohol in chronic neph- ritis, 544 diet for diabetes, 500 for obesity, 502, 503, 507, 510 for muco-membranous colitis, 534. 535 use of white meats in nephritis, 542 of fluids in chronic nephritis, 544 Von Schweninger, restriction of diet in obesity, 510 Vril Albuminous Beef-tea, 107 V. V. Bread composition, 203 6t4 FOOD AND DIETETICS Wail, absorption of milk, 123 Warren's Cooking Pot, 407, 408 Waste of food, avoidable and unavoid- able, 18 in bread-making, 199 Waste matter in meat, 62 in fish, 81, 84 Wasting diseases, diet, 513-515 Water, absorption of, 303 by intestine, not by stomach, 3°3 aeration after boiling, 306 amount of, required, 300 as source of infection, 304, 305, 306 bodily tissues, reservoirs of, 301 effect on constipation, 536 of, on foods during cooking, 404, 4°5 on dilatation of stomach, 303 escape of, from stomach, 303 filtering, 306 in animal foods, 60 m meat, 62 in milk, 112 in vegetable foods, 164 method for removing, 164 infected, not rendered innocuous by addition of wine or spirits, 306 influence of diet on amount of water consumed, 300 of increase or diminution of water on diet, 301 on blood-volume, 300, 301 on digestion, 303, 304 on metabolism, 304 loss of, caused by cooking, 64 liberal supply in typhoid fever diet, 488 proportion of body made up of, 300 restriction from diet in aneurysm, 3°3 , . , use of, in diet of infancy, 436- value in diabetes, 498 varieties of, 305 Wateriness, disadvantage in vegetable food, 164, 180 Waverley Oats, 221 Weight of body in relation to season, 50 influence on amount of food required, 43, 44 loss of, during summer months, 50 Weir-Mitchell treatment, 515 in neurasthenia compli- cating atonic dyspepsia, 533 Wet-nurse, choice of, 439 Wheat, 190 bran of, 190, 191, 192 chemical composition, 190, 191 Wheat, endosperm or kernel, 190, I9I germ of, 190, 191, 192 gluten in different kinds of, 193 grinding by stone, 192 milling by roller, 192 mill-products, 193, 194 patent preparations, 219 chemical composition, 219 rejection of germ and bran by mill- ing, disadvantages of, 194 See also Chapman's Whole Wheat- flour, Florador, Force, Granola, Granuto, Grape-nuts, Shredded Wheat Whey, 132 and cream as infant food, 473 chemical composition, 132 cure, 132 in humanized milk, 457, 458, 459 in jaundice, 133 in nephritis with constipation, 133 in typhoid fever, 133 in uric acid gravel, 133 Whisky, definition of, 355 grain whisky, 356, 357 malt whisky, 355 potheen, 357 White, W. Hale, tannic acid in tea, 319 White Cross method of milk preserva- tion, 119 Wholemeal bread, 16, 202, 210 absorption, 210, 211 chemical composition, 214 mineral matters in, 214 proteids, absorption, 211 Whole-wheat flour, value in rickets, 523 Wilks, discussion on alcohol, 351 Williams, Mattieu, staleness of bread, 206 Williams, Miss K., chemical composi- tion of fish, 79 Williamson on diabetic milk, 495 Wincarnis, 389 Wine, 372-395 acetic acid in, 377 acidity, total, of sound wine, 377 action of acids in, 392 addition to infected water does not destroy micro-organisms, 306 after bottling, 374 age of, 374, 375 alcohol in, 376, 387, 389, 392, 394, 395 as enema, 574 formation of, 372, 374 chemical constituents, 375, 395 comparative table of analy- sis, 387 colour, 373 definition of, 372 dry, 372, 3 8 7 ethers in, 378 INDEX 6i5 Wine, extractives in, 379, 394 fortified. 373, 376, 378, 392 glycerine in, 379 in chemistry, 373 in digestion, 390, 391 in gout, 386. 387 rn health, 391-395 in the cask, 374 medicated, 388 natural, 373, 379, 388 oenanthine in, 379 pasteurization, 377 pepsin wines, 338 plastering of, 383 red, 373 stimulating action of, 342, 388, 391 sugar in, 372, 378, 393 tartaric and tannic acids in, 372, 377. 393. 398 white, 373 yeast of, 373 See also Grape- wines, non-alcoholic Winter's humanized milk, 459 Winternitz and Strasser, use of milk in diabetes, 494, 495 Wolffhfigel, slow cooking, 406 Wollowicz and Parkes , effects of alcohol on the circulation, 341 Women of luxurious life, obesity in, 48 need less food than men, 48 proportion of diet at work and at rest, 48 relative values for food require- ments at different ages, 45 Woodward's analysis of colostrum, 437, 438 Work, mental, amount and nature of food required, 41 amount of proteid required when strain great, 39 digestibility of food for, more important than chemical composition, 42 effect of alcohol on, 342, 350 nitrogen and phosphoric acid, diminution of ab- sorption during, 41 Work, mental, no special brain food, 41 over-supply of food un- favourable to, 41 muscular, amount of proteid re- quired, 44 influence of, on diet, 35, 36, 43 nature of food required for, 37 vegetarian diet suitable to, 4, 180 standards of Calories required for work of different degrees of severity, 35, 36 and heat-producers, 3 Wright, Sir A. E., F.R.S., alkalinity of food and scurvy, 299 diabetic milk, 495 Wunderlich, temperature of drinks, 428 Wyeth's Beef-juice, 100, 101 Xanthin in meat extractives, 94 X-ray observation as to digestion of food, 420 Yam, 243 Yeast, marmite, extract prepared from, 97 methods of production for fermen- tation of bread, 197 of malt liquors, 365 of wines, 372 Yolk of egg, 152 calcium in, 155 iron in, 154 phosphorus in, 154 subcutaneous administration, 578 valuable in diet of rickets, 522, 523 York, diet of poorer classes in, estimated by standard dietaries, 34, 56 found to be insufficient, 56 Yorke-Davies, restriction of fluids in obesity, 510 Zomotherapy (treatment by raw meat or raw-meat juice), 556 indications for, 556 Zuntz, fusel-oil, 364