} ft Advertisements—South Kensington Museum Art Handbooks. KING,S COLLEGE, LONDON. (Classes established by aid of the City Guilds.) PRACTICAL FINE ART, UNDER THE DIRECTION OF PROFESSOR PHILIP HENRY DELAMOTTE. The Classes in Practical Fine Art will be open to Students in the morning from 10 to i o'clock every day, and on the evenings of Tuesday and Thursday from 7 to 9. On Tuesday, at 11 in the morning and 7 in the evening, there will be a Lecture, accompanied by illustrations on some branch of the Art of Design. Individual instruction will be given to Students both in the techni- calities of various Arts and in the more general requirements of Designing. The copying, imitating, and originating of beautiful Forms and the applying them to various materials will be aimed at. The following branches of Practical Fine Art will be included in the Course. Decorative Painting. Furniture. Pottery. Carving. Modelling. Metal Work. Textile Work. Designing on Wood. Painting on China. Etching on Copper and Steel. Designs for Bookbinding. The Study of Plant Form as applied to General Decora- tion. METALLURGY, under the direction of PROFESSOR A. K. HUNTINGTON. The Laboratory for instruction in Metallurgy will be open to Students every day from 10 to 4 (except on Saturday, when the College closes at 1); and on Monday evenings from 7 to 9. • • Lectures will be delivered on Monday and Thursday afternoons at 3 o,clock, and on Thursday evening at 7 o,clock, on the following subjects: 1. The Principles of Metallurgy. 2. Physical Properties of Metals. 3. Fuel, its Physical and Chemical Qualities. 4. Materials used in the Construction of Furnaces. 5. Metallurgical Processes. For further particulars, including fees, apply to T. W. Cunningham, Esq., Secretary, King's College, London. * Advertisements—South Kensington Museum Art Handbooks. THE FINEST TEA THE WORLD PRODUCES. Cooper Cooper & Co. undertake to answer the oft-heard question, "Why is tea so dear?" and they say that it is simply because the Public in this, as in other matters, are powerless to insist on having their share of the advantages which result from falling markets. Tea, in fact, was never so cheap to buy since it was first imported into England, as may be easily ascertained by a reference to the current market reports, and yet relatively the retail price was never so exorbitant. Now Cooper Cooper & Co. have resolved to rectify this discrepancy, and to this end they undertake to sell the best teas that can be purchased at their respective prices at a small commission only on the actual prices paid to the importers. This system of business is specially intended to bring the public into partnership, as it were, or at all events to enable them to become participators in the great margin of profit which lies between the wholesale and retail price of tea. Cooper Cooper & Co.'s prices will be found to be ninepence per pound less money than those usually charged for identical qualities, while their highest class first crop teas at 3s. a pound are of a quality that is very rarely to be obtained at any price whatever. Selected from the List of Choice Black Teas. 1. The finest Lapsang Souchong, 3s. a lb. This tea is exquisitely delicate in flavour, silky on the palate, and one of the finest teas ever imported into England. 2. The finest Moning Congou, 3s. a lb., is soft, silky, delicately flavoured tea, and drinks full and round on the palate. 3. The finest Kyshow Congou (the Prince of Teas), 3s. a lb., is a brisk, pungent, deliciously flavoured tea, of amazing strength, beautifully manipulated—full of flower. To taste this tea in perfection it should be drunk without cream or milk, as these to a great extent hide the pungent, malty flavour which is so grateful to the palate. 4. The finest Assam Congou, 3s. a lb. This is a very strong tea of Indian growth, draws a deep red liquor, is very pungent, a little coarse, but drinks full in the mouth. It is quite a distinct class of tea, rather peculiar, and not appreciated by all; in fact, to like it requires an acquired taste. Unnumbered Teas. In Slate-tinted Bags.—Choice Moning Congou, 2s. 6d. a lb. This is the best of the second crop, and possesses great strength and good flavour, and will be found always good alike. In White Bags.—Marvellously good Black Tea, 2s. a lb. This tea will be found per- fectly pure, of fair strength and attractive flavour. Cooper Cooper 6V» Co.,s Prices are for nett Cash only, without Discount. COOPER COOPER & CO., (exclusive teamen), 50, King William Street, London Bridge; 63, Bishopsgate Street Within, E.C.; 268, Regent Circus, W.; and 35, STRAND, W.C. (near Charing Cross). South Kensington Museum Art Handbooks. INDEX TO PARTICULARS OF MANUFACTURES AND ILLUSTRATIONS OF TRADE ANNOUNCEMENTS. FAGS Art Furniture—Messrs. Druce & Co.'s 3 Autotype Fine Art Gallery—The Autotype Company's 4 Books, Art—Messrs. Smith, Elder, & Co.'s 6 Books, Art—Messrs. Chapman & Hall's 12 Carpets (Turkish, Persian, and Indian)—Messrs. Cardinal & Harford's . . 14 Carpets (Persian, Indian, and Turkish)—Messrs. Watson, Bontor, & Co. 's . 13 Chemical Food—Messrs. Liebig & Co.'s 8 Corn Flour—Messrs. Brown & Poison's 10 Japan, China, and India Art Manufactures—Messrs. Farmer & Rogers's . . 13 King's College '. . . . . , . . . . , . 1 Knockabout Bag—Messrs. L. & S. Harron's .9 Mosaic Pavement and Venetian Glass — Messrs. Dr. Salviati, Burke, & Co.'s 4th page of Cover Macassar Oil, Odonto, and Kalydor—Messrs. A. Rowland & Sons' 2nd page of Cover Mincing Machines, &c.—Mr. J. F. Lovelock's 9 Music—Messrs. Novello, Ewer, & Co.'s 3 Musical Instruments—Messrs. Keith, Prowse, & Co. 's 7 Ointment, &c—Mr. Thomas Holloway's p Pens, Steel—Messrs. Joseph Gillott & Son's 12 Persia, Japan, China, and India Art Manufactures — Messrs. Lasenby Liberty, & Co.'s 3rd page of Cover Tea—Messrs. Cooper Cooper & Co.'s 2 Yorkshire Relish, &c.—Messrs. Goodall, Backhouse & Co.'s . . .it SOUTH KENSINGTON MUSEUM SCIENCE HANDBOOKS. [BRANCH MUSEUM, BETHNAL GREEN.] FOOD. /* FOOD ?rs-i I SOME ACCOUNT OF ITS SOURCES, CONSTITUENTS AND USES. •r1 . BY Sir ArkrCHURCH, M.A., Oxon., Professor of Chemistry in the Agricultural College, Cirencester. FOURTH THOUSAND. Published for the Committee of Council on Education BY CHAPMAN AND HALL, 193, PICCADILLY. 1880. CHARLES DICKENS AND EVANS, CRYSTAL PALACE FKESS. PREFACE. scope ma u»es This book is meant to serve two ends. In the first of the Present , ... i i ,- i • . ,., volume. place it is intended for the instruction of those visitors to the Bethnal Green Museum who may wish to study the collection of food-products there displayed. Secondly, it has been so written that its pages may be read, it is hoped with profit, apart from any such exhibition of the actual materials of food. origin of the A few words concerning the origin and character Food Collection. Qf ^ Foo(j Collection may My here be given The first suggestion of such a series was made by Thomas Twining, Esq., of Perryn House, Twickenham, who planned an Economic Museum, illustrative of the materials and processes of every-day life. The Food Collection was first arranged in 1857, when it became part of the General Museum of the Science and Art Department. For some time it was under the direction of theRt. Hon. Lyon Playfair, C.B.,M.P., who has himself done much good service through his studies of the relations between Food and Work. The late Dr. Lankester was subsequently entrusted with the management of the collection. It has been recently re-arranged, enlarged, and re-described by the author of the present volume. Nature of the The Food Collection contains two distinct classes of Food collectton. Specimens. One of these comprises all the usual and important articles of human food, whether derived from animals or plants. The other class of specimens illustrates, by what may be termed displayed analyses, the chemical composition of many indi- vidual food-materials, such as breadstuff's, pulse, milk, eggs, and butchers' meat. Moreover, in this part of the collection the uses of food are shown in relation to the nutrition and work of the human body. An attempt has been made to. let the Food Collection tell its own story. For while each important specimen and illustration is labelled in the usual way, longer and fuller descriptions, in conspicuous CONTENTS. PART I.—Of Food in General. § i. The Uses of Food .... § 2. Composition of the Human Body § 3. The Classification of Food § 4. Water as Food .... PACK I 3 9 10 § 5. Salts or Mineral Matter in Food 23 § 6. Carbon Compounds or Heat-Givers 26 § 7. Nitrogenous Compounds or Flesh-Formers ... 40 § 8. A Day's Ration 48 PART II- Of Vegetable Foods. § 1. The Cereals or Bread Stuffs 57 § 2. Pulse, &c. 82 § 3. Roots and Tubers 87 § 4. Leaves, Stems, Stalks, and Whole Plants ... 97 § 5. Saccharine and Oily Fruits 112 PART III.—Of Animal Foods. % 1 § 2. §3 §4- § 5. §6. Milk and Dairy Produce Eggs .... Butchers' Meat Poultry, Game, &c. Fish, &c. Bacon and Preserved Meats 132 146 148 155 158 161 viii CONTENTS. PART IV.—Of Food-Adjuncts. PAGE § i. Beer, Wine, and Spirits 169 § 2. Condiments, Spices, and Flavourers 184 § 3. Vinegar, Pickles, and Acids ...... 193 § 4. Tea, Coffee, and Cocoa 196 § 5. Tobacco and Opium ........ 203 PART V.—Of Diet and Dietaries. § r. Food-equivalents 208 § 2. Public Dietaries 213 § 3. National Foods 216 § 4. Ancient Foods 218 Index 221 FOOD. PART I.-OF FOOD IN GENERAL. § i.—The Uses of Food. In order to show clearly what is the nature of the food of man, and what the work which it has to perform in the body, we may make use of a comparison which will be familiar enough to our readers. Let us compare the complex, living machine of the human body with a locomotive engine. In the case of the engine, we have, first, its material structure; secondly, the fuel in the form of coke or coal with which it is constantly supplied; thirdly, the air which enables the coke to burn; fourthly, water; and fifthly, waste, in the shape of ashes, cinders, and gases. In the case of the human body we likewise have, first, a material structure; secondly, fuel, in the form of our daily rations of food; thirdly, air, which enters into the lungs, and serves to consume the food; fourthly, water; and fifthly, the waste-products, which are thrown out of the body by different channels. In both cases the fuel is burnt by the aid of air, the oxygen of which unites with the combustible part of the fuel, and in so doing the power of doing work or potential energy in the materials which combine is set free as heat and motion. In the steam-engine this heat is chiefly used to change water into steam, and then, by the expansion which 4 COMPOSITION OF THE HUMAN BODY. As yet no complete chemical examination of the total con- stituents of a healthy human body has been made; we cannot, therefore, state the amounts of the several ingredients which it contains, with exactness, but the figures which follow will afford some notions on this interesting subject. In making our cal- See Case i. culations, we assume that we are analysing (that is, chemically pulling to pieces) a man in perfect health, 25 to 30 years of age, 5 feet 8 inches in height, and weighing 11 stone, or 154 pounds. Throwing out of our list the minuter and less certain details, we find that The human body is made up of the following compounds: 1. Water: which is found in every tissue and secretion, and amounts altogether to - - - - - 109 o o 2. Fibrin, and similar substances, forming the chief solid material of muscular flesh, and also occurring in blood 15 10 o 3. Phosphate of Lime: in all tissues and liquids, but chiefly in the bones and teeth - - - 8120 4. FAT: a mixture of three chemical compounds; dis- tributed throughout the body - - - 480 5. Ossein : the organic framework of bones, and the chief constituent of connective tissue; it yields gelatin when boiled 4 7 350 6. Keratin, with other similar nitrogenous compounds, forms the chief part of the skin, epidermis, hair, and nails, and weighs about - 420 7. CARTILAGIN: a nitrogenous substance, is the chief con- stituent of cartilages; it resembles the ossein of bone, and amounts to I 8 o 8. HAEMOGLOBIN, a very important nitrogenous substance containing iron ; it gives the red colour to the blood, and amounts to- - - - 180 n. Albumen, a soluble nitrogenous substance, is found in chyle, lymph, blood, and muscles - I 1 o 10. Carbonate of Lime is found chiefly in bone - - 10 350 11. Kephalin, with myelin, cerebrin, and several other nitrogenised, sulphurised, or phosphorised compounds, is found in brain, nerves, &c - 0130 12. Fluoride of Calcium is found ckiefly in bones and teeth o 7 175 ELEMENTS IN THE HUMAN BODY. 5 lb. oz. gr. 13. Phosphate of Magnesia, chiefly in bones and teeth 070 14. Chloride of Sodium, or common salt, occurs through- out the body - 070 15. Cholesterin, Inosite, and Glycogen are compounds containing carbon, hydrogen, and oxygen, found in brain, muscle, and liver ... 030 16. Sulphate, Phosphate, and Organic Salts of Sodium are found in all liquids and tissues • o 2 107 17. Sulphate, Phosphate, and Chloride of Potassium are found in all tissues and liquids - 0 1 300 18. Silica occurs in hair, skin, and bone • o 0 30 154 0 o In giving the foregoing list we do not pretend to do more than approximately represent the quantities of the several com- pounds present in the body; indeed, these quantities are for ever changing. Nor does this catalogue include every kind of mate- rial necessary to the human organism, or found in it at any given time. There will be present food in different stages of digestion; carbonic acid gas with free oxygen; and a great number of com- plex organic compounds, each occurring, it may be, in very small quantity, but still not on that account without importance. All these matters are either omitted from our list, or else must be considered as included under the names given to better known or more abundant compounds. Specimens of Now that we have seen of what materials, or compounds which proximate principles, as they are often called, the are constituents . . of the Human human body is built, we must pass on to inquire Body are shown in Case j. into the nature of these matenals themselves. They are compounds, that is, are made up of two or more separate and distinct sorts of matter—that is of two or more elements. Water, for example, is a compound of two elements .—hydrogen and oxygen; fibrin contains, besides these two elements, three others, namely, carbon, nitrogen, and sulphur; yet no one of the compounds contains all the sixteen elements 6 ELEMENTS OF THE HUMAN BODY. necessary to the body as a whole—indeed, no single compound present has in it more than six of these. Before trying to find out how much of each element is present in the body, let us see in what compounds the several elements occur. WATER consists of hydrogen and oxygen. Fibrin, Albumen, Ossein, Keratin, Cartilagin, contain carbon, hydrogen, oxygen, nitrogen, and sulphur. HAEMOGLOBIN, all the above elements with iron as well. Kephalin and Myelin contain carbon, hydrogen, nitrogen, phosphorus, and oxygen. Cerebrin and Kreatin contain carbon, hydrogen, nitrogen, and oxygen. Fat, Cholesterin, Inosite, and Glycogen, contain carbon, hydrogen, and oxygen. Phosphate of Lime contains calcium, phosphorus, and oxygen. Carbonate of Lime contains calcium, carbon, and oxygen. Fluoride of Calcium contains calcium and fluorine. Phosphate of Magnesia contains magnesium, phosphorus, and oxygen. Chloride of Sodium contains sodium and chlorine. Sulphates contain different metals with sulphur and oxygen. Silica is a compound of silicon and oxygen. The following is a list of all the elements that are invariably found in the human body. It will be seen that there are sixteen of them in all, seven of these being metals, and the remainder (which we place first) non-metallic: Case 1. Elements of the Human Body. lb. en. gr. 1. Oxygen : a permanent gas, the great supporter of com- bustion. This gas constitutes f ths of the weight of water and Jth of the air. The quan- tity in the human body would fill a space of some 1,290 cubic feet, and would weigh about 109 2 335 2. Carbon : a solid, occurs nearly pure in charcoal. The carbon in the body is variously combined with other elements, and by its burning sets free heat, and produces carbonic acid gas - 18 11 150 ELEMENTS OF THE HUMAN BODY. ID. 01. gr. 3. Hydrogen : a gas and the lightest substance known. It occurs mainly in water ; the quantity in the human body wrald fill a space of some 2,690 cubic feet, and would weigh about - 14 3 150 4. Nitrogen : a gas without energetic properties. It is an essential part of all bone, and blood, and muscle. The quantity in the body would occupy about 66 cubic feet, and would weigh about -------- 4140 5. Phosphorus: a solid. It occurs specially in various compounds of the bones and of the brain. It burns so readily in air, that it is here kept under water. In the human body we find about -- I 12 25 6. Sulphur: a yellow combustible solid, often called trim- stone. Like all the preceding elements, it is found in all the tissues and secretions of the body, but always in combination. It amounts to------- 080 7. Chlorine : a greenish-yellow gas, found in the body chiefly in union with sodium, the compound being common salt . The chlorine in the human body would, if free, fill a space of I cubic foot and 772 cubic inches, and would weigh ....... 04 150 8. Fluorine: hardly known in the separate state, but probably a gas. It is found united with calcium in the bones and teeth. The quantity in the body would probably fill a space of 2 cubic feet and 510 cubic inches. It would weigh 03 300 9. Silicon : a solid, occurring in union with oxygen, in hair, bones, blood, bile, saliva, and skin - - o 0 14 10. Calcium: a metal, the basis of lime. It occurs chiefly in bones and teeth - 3 13 190 11. Potassium: a metal, the basis of potash. It is lighter than water, and when placed on it burns with a lilac flame. It occurs mainly as phosphate and chloride 03 340 12. Sodium : a metal, the basis of soda. It is lighter than water, and must be kept from the air. It occurs chiefly in union with chlorine as com- mon salt, but also in other compounds in bile o 3 217 13. Magnesium : this metal is found, in union with phos- phoric acid, mainly in bones ... 02 250 8 NATURE OF FOOD. lb. oz. gr. 14. Iron : this metal is essential to the colouring matter of the blood. It occurs everywhere in the body o o 65 15. Manganese : a metal much like iron. Faint traces occur in the brain, and decided traces in the blood. 16. COPPER: traces of this metal are invariably found in the human brain, and probably also in the blood. Lithium and lead have been frequently found, but not in quantities that could be weighed, in both muscles and blood. It is not certain, however, that these elements are absolutely essential parts of the human body. We have now seen of what compounds and elements the human body is made up, and, therefore, we may now inquire what must be the quantity and character of the food which has to furnish these compounds. But our inquiry must also include another point—namely, the materials with which the machinery of the human body is kept in action. In short, we must study food not only as a constructive and reparative material, but as fuel—as the source of heat and force. The materials of the human body, that is, the compounds of elements of which it is constructed, are, in most instances, either identical with, or similar to those compounds which are contained in food. Naturally we should expect this to be the case with animal food, but it is also true to a great degree in the case of vegetable products. And here it must be recollected that, with rare exceptions, compounds, and compounds only, not the separate elements, are capable of nourishing the body. Oxygen, indeed, is used in the free or uncombined state as an element, but the office performed by oxygen, as we have before explained, is quite different from that of the materials usually called food. It will be convenient to introduce here a classified list of the several compounds which occur in the vegetable and animal products used as food. A classification which takes into account both the chemical composition of these compounds and the purposes which they serve in the body will be adopted. COMPOUNDS IN FOOD. § 3.—Chemical and Physiological Classification of Food. Class I.—Nutrients. Division 1.—Incombustible Compounds. Group i. Water—The carrier of nutritive materials and waste products: forms an essential part of all tissues. Group ii. Salts or Mineral Matter—such as common salt and phosphate of lime, which serve to effect changes and build up certain tissues. Division 2.—Combustible Compounds. Group iii. Carbon Compounds, such as starch, sugar, and fat, which serve to keep up the heat and movements of the body by the discharge of their potential energy during oxidation in the organism. The fat of the body is formed in part from fat or oil in the food. The members of this group are often called in the following pages "heat-givers," a term which is equivalent to "force-producers." Appendix to Group iii. Gum, mucilage, pectose, and cellulose, approach starch in chemical composition, and probably serve, in some measure, the same end. Group iv. Nitrogen Compounds, such as fibrin, albumen, and casein, the chief formative and reparative compounds of food: they also may yield fat, and by their oxidation set free heat and motion. Here- after we shall name them "flesh-formers," except where we set them down as albumen, &c, or as albuminoids. Appendix to Group iv. The ossein of bones and gelatin; cartilage and chondrin; keratin and elasiin from skin and connective tissue,—approach the albuminoids in composition, and may serve, in a measure, similar purposes in the body. Class II.—Food Adjuncts. Group i. Alcohol, as contained in beers, wines, and spirits. Group ii. Volatile or Essential Oils, and other odorous and aromatic compounds, as contained in condiments, like mustard and pepper, and in spices, as ginger and cloves. Group iii. Acids, as citric acid in lemons, malic in apples, tartaric in grapes, oxalic in rhubarb, and acetic in vinegar and pickles. Group iv. Alkaloids, as caffeine in coffee and tea, theobromine in cocoa, and nicotine in tobacco IO WATER. Specimens of the compounds found in Foods are shown in Cases 2 and 3. We may now proceed to give a brief account of each Nutrient, following the order in which these compounds are classified in the preceding Table; the Food Adjuncts will be considered further on. § 4.—Water. Cases 4,5, and 6. This important constituent of food is the carrier of food into and through the system, and forms more than two-thirds of the whole body. Water is contained not only in the liquids drunk as beverages, but in all kinds of solid foods. Here is a list of the Quantities of Water in ioo lb. of Different Kinds of Food. Fresh oatmeal - Maize meal Wheaten flour - Barley meal Peas - Haricot beans - Rice - Bread Potatoes - Vegetable Food. lb. 5 14 14 14 14 14 IS 40 75 lb. Grapes ----- 80 Parsnips ----- 81 Beetroot 82 Apples - - - - - 83 Carrots 89 Cabbages 89 Onions 91 Lettuce .... 96 Butter Bacon Cheese Eggs Animal Food. lb. - 10 - 22 34 72 Lean of meat Fowl Fish - Milk. lb. 73 73 74 86 Although the above proportions of water seem generally large, these foods do not suffice alone to supply all the water required by man. As every pound of perfectly dry food should be accom- panied by four pounds of water, it is found necessary to consume water itself, or some beverage containing little else but water. 12 WATER. heat the dry residue gradually hotter and hotter. If the original residue is white and powdery in appearance, that is, so far, a good sign; but if it is partly white and partly yellowish or greenish, and especially if there are gum-like stains round the residue, then on heating these parts of the residue we shall probably see them darken, fuse, and burn away in part, giving Such strongly- out fumes having a disagreeable smell. If the of good and bad blackening is considerable, much organic matter waters are shown . . in Case 5. is present; but if the smell is offensive (like burnt feathers), then it is certain that the organic matter is of animal origin, and is, therefore, more likely to be unwholesome, or even poisonous. Another test for organic matter in water may be used with some facility. If a water contains substances derived from the decay of animal or vegetable matters, such as those in sewage and manure, and the refuse of plants, then it is found that such a water will destroy the beautiful purple colour of a chemical substance called permanganate of potash. The reason for this is as follows: The decaying organic matters of the water attract oxygen strongly when it is presented in certain states or forms. Now, a solution of the above permanganate contains much oxygen just in the right state to be so attracted and removed. By its removal from the permanganate the composition of that substance is altered, and its colour destroyed. The more organic matter in the water, the more permanganate will be decolourized. The test may be thus applied. Fill a clean white teacup with the water to be tested. Add about 60 drops, or a drachm, of weak sulphuric acid; stir with a clean slip of window glass; now pour in enough of a weak solution of permanganate of potash to render the water a rich rose colour. Cover the cup with For specimens a c^ean glass plate. Now, if there be much organic waters* "tested1 matter m tne water, the colour will go in a few see Case s. minutes, and more permanganate may be added, and still lose its colour. It must be recollected in using this test SURFACE AND SHALLOW WELLS. 15 suffers little change; if on one of tiles, it will take up scarcely anything save a little decaying vegetable matter from the mosses and lichens usually found on such a surface; but if it falls on a limestone roof it dissolves calcareous as well as decaying organic matters. Further, rain-water acts on leaden pipes and cisterns, becoming charged with this injurious metal. 2. River-water.—Directly rain-water comes into contact with the land it acquires fresh impurities. Even rain-water stored in tanks or cisterns may become decidedly unwholesome; but when, as in most parts of England, rain falls upon pasture land, arable land, or inhabited places, then its character is altogether altered for the worse. From the bones and other manures applied to farm lands, from vegetable and animal refuse, particularly the sewage-matter from human habitations, rain-water takes up, not only mineral matters, but decaying organic matters. If the water thus polluted does not have to pass through thick layers of •chalk, or limestone or sandstone rock, but runs off the surface or through drain-pipes, it is charged with injurious matters. It often passes directly into rivers, which generally receive also the direct inflow of sewers, the foul discharges of factories, and the .droppings of the farm animals which are pastured on the banks. Thus the use of river-water for drinking and cooking is not to be recommended. It is fraught with risk to health. 3. Surface-well water resembles river-water, but is likely to be still more loaded with dangerous impurities. For in a river the decaying animal and vegetable matters present become, in part at least, oxidized and rendered harmless by the dissolved oxygen of the water, aided by the suspended earthy or mineral matters. It will not, indeed, be safe to trust to such natural purification, for it is only partial at the best, and may wholly fail to remove the most deadly of the organic matters, the special poisons, for instance, of typhoid fever and cholera. With greater force the same statement may be made in regard to surface-wells. These merely receive surface soakage from the immediate locality: 16 DEEP-WELL WATERS. they are often near privies and pigsties, and not infrequently they are in communication with a neighbouring sewer or cesspool. Many years ago the writer of these pages discovered, by means of spectrum analysis, that if a salt of the metal lithium was put into certain privies, cesspools, and leaky sewers, it could be soon detected in the water of neighbouring shallow wells in which it was not naturally present. In fact, wherever a clay or other water-bearing material keeps up the water, and there is a loose soil or gravel above, it is pretty nearly certain that the shallow wells dug in the earth will be in communication with the neigh- bouring cesspools. Often the level of the liquid in both will be the same. True, the sewage-water will not pour in unfiltered and turbid, but it will pour in for all that, and mingle with the natural water of the well. We cannot depend upon the purifying effect of the few feet of gravel or sand that may separate the well from the cesspool. To the eye, and even to the taste, there may be no signs of the disgusting and dangerous pollution, but the pollution may be there, nevertheless. Sometimes these waters may be taken—it may be for years—without bad results, but an epidemic may come, and then these waters may spread, and often have spread, death around. The poisons producing cholera and typhoid fever are contained in the discharges from the bowels of persons suffering from these diseases, and a small quantity of such discharges finding its way into water used for drinking, has been clearly proved to have been the cause of a frightful mortality amongst persons using these waters. There is scarcely a single shallow well in London which can be pronounced safe. 4. Deep-well waters are generally palatable as well as free from injurious substances. The organic matters which the rain- water has carried down with it into the rocky layers below the surface, have been so altered by their passage through great thick- nesses of stone, that they have become oxidized, or in common language burnt. It may seem strange to talk of burning taking place in water; but the process of oxidation, whether slow or fast, HARDNESS OF WATER. 17 whether it occurs when a candle burns in air, or food in the body, or animal and vegetable matter in water, is essentially the same process. The new products formed are harmless, indeed they may be even useful, but the oxidation must be complete. The pro- cess is not completed in shallow-well waters; it generally is in deep-well waters. The final and harmless products are there. The nitrogen of the animal matters appears at last in the form of nitrates and nitrites; the carbon, as carbonic acid gas; and the hydrogen, as water. The nitrates and nitrites may be regarded as a sign of previous pollution, but they are quite harmless, and must occur in all the deep-well waters of a country like England, where so much of the land which receives the rainfall is under cultivation, and consequently manured. Most farm lands in England receive yearly in farm-yard manure alone, nearly 30 pounds of nitrogen per acre, and this must find its way into rivers, wells, and springs. Deep-well waters are usually harder than any of the waters before considered, for they will have dissolved out much calcareous, magnesian, and alkaline salt during their long course underground. They will probably, on the average, contain about 30 grains per gallon of total dissolved substances. 5. Spring waters are generally palatable and wholesome. They vary in hardness and as to total solid matters dissolved, according to the more or less insoluble nature of the rocks through which they have passed or which throw them out. The Rabate Fountain at Balmoral contains less than 1 grain per gallon of dissolved matter, while the average of the springs of the Lias shows 25^ grains. Hardness of Water. This may, perhaps, be the best place to introduce a few words about that quality of water which is usually called hard- ness, and to which we have before frequently alluded. In ordi- nary waters the chief hardening ingredients are salts of lime and magnesia. These decompose soaps, forming white, curdy, and c 18 HARDNESS OF WATER. insoluble compounds—lime and magnesia soaps, in fact, which contain fatty acids united with these earthy bases. The alkali in the original soap unites with the carbonic or sulphuric constituent of the lime and magnesia salts, forming carbonate of soda, which has cleansing properties, or sulphate of soda, which is quite useless. If then a water be hard from earthy carbonates, how- ever disagreeable washing with it becomes, still the soap, though it will not lather, cleanses. But if earthy sulphates predomi- nate, then neither lathering nor cleansing can take place until the soap has destroyed these salts. In using a hard water for washing the hands, we instinctively use but little water, rubbing the soap between the hands wetted with water but not immersed in it. But in soft water we find that a very little soap will cause the whole of the water to lather. It is not ascertained that hard waters are unwholesome because of their hardness, though much mineral matter dissolved in a water is objectionable. But for washing linen and for baths hard waters are objectionable, because of the white, useless, curdy matter which is formed with soap, and which wastes much soap, and may, if not removed Case 4 con- by rinsing and rubbing, stick to the skin. The tains illustrations' ° ° stroth d Sb"p dif* amount of soap destroyed or curdled by 100,000 lb. akolofrath™*du* (10,000 gallons) of various waters is seen in this solved matters taHl*» they contain. IdUie. Waters. Soap destroyed, lb. Thames 212 Lea ....... 204 Kent Company's ..... 265 Caterham - - - - - 84. Worthing 285 Leicester ...... 161 Manchester 32 Preston ...... 80 Glasgow (Loch Katrine) ... 4 Lancaster ...... \ The hardness of water may be tested by a standard solution of soap, known as Clark,s Soap Test. IMPURITIES OF WATER. i9 Organic Pollution of Water. The organic impurities of water are even more important than the mineral impurities. Organic impurities, such as sewage con- tains, and to which reference has been already made more than once, should never be allowed to enter into a water used for drinking purposes. If they, have entered, we can prove their actual presence by the amount of carbon and nitrogen in organic Gombination which the polluted water contains; while we can trace their previous entrance by the nitrates and nitrites which they yield. If we assume that average London sewage contains 7 grains of combined nitrogen per gallon (or 10 parts in 100,000), then if we find 3 ^ grains in a gallon of water, it may be considered that the particular sample of water examined had received animal pollution equal to just half its bulk of sewage. This pollution may not have arisen from actual house sewage, but from animal matters in decay, farmyard manure, guano, &c. Nor can we say that water which has been thus polluted is necessarily now un- wholesome. Such changes may have occurred to the offensive and unwholesome nitrogenous decaying matters as to have turned them into harmless mineral compounds—mere signs of previous • contamination. The preceding remarks will, it is hoped, render clear the meaning of the expressions and numbers used in the monthly reports concerning the metropolitan water supply which are published by the Registrar-General. So far, little has been said about the visible suspended matters found in many water supplies, attention having been drawn chiefly to the invisible dissolved impurities. In settling-tanks, and by passing through filter-beds, the muddy water of the Thames and Lea may be rendered bright and clear. For if the impurities of water were suspended in it, but not dissolved, thorough filtration would remove them. But, unfortunately, perfectly clear or bright waters may be as unwholesome, or more so, than muddy ones. Yet filtration does effect some change for the better even in the c 2 2o FILTERS. worst waters, provided that the water filters slowly, and that the material of the filter is of the right sort and not rendered inert by previous use. An old filter, in which the charcoal, &c., has not been properly renewed, may give impurities to a water instead of removing them.* The best materials for filters are these three :— i. Gravel and sand, if sharp and clean. 2. Charcoal, especially burnt bone. 3. Spongy metallic iron. The water supplied to London is filtered by means of gravel and sand, which generally cause the removal of 1 grain per gallon of dissolved matter and all the suspended particles. Animal charcoal, prepared by heating bones to redness in closed iron retorts, is very effective, when fresh, in removing much organic dissolved matter and mineral salts from water filtered through it. But its softening effect is not of long continuance. A cheap and simple filter may be made by taking a large common flowerpot, thoroughly soaking it in clean water first, and then filling it up in the following way:—Plug the hole at the bottom with a piece of sponge, not too tightly; put on this a layer of animal charcoal, then a layer of clean sand, and on the top a layer of coarse clean gravel. Many of the filters now manufactured are constructed in a similar way. Wherever possible it is best to let the water ascend through the filter. This may be done in cisterns and siphon filters. As a filtering material, nothing equals spongy iron. This was introduced by Mr. G. Bischof, and is most effective in reducing the hardness of water (often by two-thirds its original amount), and in removing the dissolved organic matter. There * Filters of different kinds are shown in the collection. The actual process of filtering water through sand, gravel, and charcoal is exhibited, together with samples of the materials used in the construction of filters. SOFTENING WATER. 21 is, of course, much risk in trusting to any method of filtration for removing deadly or unwholesome matters from drinking waters, but if reliance can be placed on any material for this purpose, it would probably be on spongy iron. There are two metallic impurities which may be found in water used for drinking. One of these is iron, which cannot be considered injurious to health, though its presence may render the water unpleasant to the taste and unsightly. This iron arises from the iron mains through which the water is conveyed. These ought always to be coated inside and out, when freshly cast, with a mixture of pitch and heavy coal or mineral oil. The pipes are heated to 5000 Fah., and then dipped into the hot mixture. The black shining varnish thus produced protects the pipes from change and the water from contamination. The other metal occurring in some waters is For examples ° of the action of jea(j This is derived from leaden pipes and water on lead, see * r Case 5- leaden cisterns, but it is scarcely ever found except in rain-water and very soft water: in these it may be present in dangerous amount. It may be detected by the brown tint produced on adding a drop of hydrochloric acid and some hydrosulphuric acid water to the suspected water. We may now consider the only truly chemical process adopted on a large scale for improving the quality of water, for filtration is, in the main, a mechanical operation. There is a plan of softening hard water by the use of lime; it was invented by the late Dr. Clark, of Aberdeen. Waters from the chalk, limestone, and oolite may be made to lose most of their hardness by this process, just as effectually as by boiling. But if a water is not softened by boiling it cannot be softened by Clark's process, which is competent to remove the carbonates of lime and magnesia, but not the sulphates. Clark's For iiiustra- process may be thus carried out in the case of the tions of Clark's „___ * rt process of soften- kast London Company s water. Slake 18 ounces ing waters, see .... . ... , Case 5. of freshly-burnt quicklime m a little water; when 22 WATER-SUPPLY OF LONDON. the lime has fallen to powder, add enough water to make a thin cream with this powder, and stir the mixture in a pail. Then pour this cream into a cistern containing 50 gallons of the water to be softened, rinsing the pail out with more water, but not pouring out any lumps of lime that may have settled. Let into the cistern the remainder of the 700 gallons of water which 18 ounces of lime can soften, and take care that a thorough mingling of the water and lime occurs. The added lime seizes the carbonic acid gas which held the carbonate of lime in solution, and so both the original carbonate of lime and that formed in the process fall together as a white sediment. This takes some time to settle— from 12 to 24 hours—but the water may be used for washing before it has become quite clear. This process is carried out on a large scale at Canterbury, Tring, and Caterham. At Canterbury 110,000 gallons are softened daily by the addition of 11,000 gallons of lime-water, the total impurities of the water being thus reduced from 23^ grains per gallon to less than 8}4- And not only are hardening matters thus removed, but organic substances as well. The process purifies, to some extent, as well as softens; and the method is not only effective, but cheap. It would require 20^ cwt. of soap, costing ^47 if. &d., or 4^ cwt. of carbonate of soda, costing £2 17s. 6d., to soften the same quantity of water which could be treated by Clark's process for &d., the cost of 1 cwt. of quicklime. London Water. London, with its suburbs, may be assumed to contain about four millions of inhabitants—or four persons out of every thousand now living on the whole globe. London is supplied with water by eight private companies, which provide a daily supply of about 114 millions of gallons. The following table gives the names of SALTS IN FOOD. 23 these companies, the sources of the water which they supply, and the daily amount:— Water Companies. Sources of Supply. Daily delivery in Gallons. East London Thames above Sunbury, and Lea 21,000,000 West Middlesex Thames above Hampton - 9,700,000 Grand Junction Thames near Hampton - 12,300,000 Southwark and Vauxhall Thames near Hampton - 17,500,000 Lambeth - Thames near Moulsey - - 12,500,000 Chelsea - Thames near Moulsey - - 10,000,000 New River - Lea, and springs, and deep wells - 22,000,000 Kent ---- Deep wells in chalk - 9,000,000 Some idea of the vastness of the quantity of water supplied to London may be obtained by comparing its bulk with that of a familiar building. A day,s water supply would require a tank equal in area to Westminster Hall, but the walls would have to be carried up to the height of 1,140 feet, or nearly three times the height of the cross on St. Paul,s Cathedral. And this quantity of water will not suffice for the increasing population as years go by. In 1850 the gross daily delivery was 44,500,000 gallons; in 1856 it had reached 81,000,000 gallons, and now stands at 114,000,000 gallons. § 5.—Salts, or Mineral Matter, in Food. The importance of water as a constituent of food has obliged us to dwell upon the subject of water supply at some length. Turning again to the classified list of Nutrients on p. 9, we find next to water a group of oxidized or incombustible ingre- dients, called salts, or mineral matter. These occur, as we have seen, in most drinking waters, and are found also in all parts of plants and animals used as food; while one of them, common salt, the chloride of sodium, is added purposely to food—indeed is the only solid mineral substance so added and consumed. 24 SALTS IN FOOD. The quantity of mineral matter contained in some important articles of vegetable and animal food is shown in this table :—- Mineral Matter in 1,000 lb. of 13 Vegetable Products. Apples Wheaten flour Turnips Potatoes - Barley Cabbage - Bread lb. 4 7 8 10 11 12 12 lb. Watercress - - - - 13 Maize 20 Oatmeal 21 Peas 3° Cocoa nibs - - - - 36 Wheaten bran - - - • 60 Mineral Matter in 1,000 lb. of 4 Animal Products. Cow's milk Lean of mutton lb. - 7 - 17 Eggs (without shells) Gloucester cheese lb. - 18 - 5° It is not to be supposed that the mineral matter entered in these tables is in all cases of the same composition. It varies greatly in the different products named. In most seeds and fruits there is much phosphate in the mineral matter, and in most green vegetables much potash. One important kind of mineral matter alone is deficient in vegetable food, and that is common salt. This compound must be added in large quantity to the food of persons living exclusively on vegetables; while, on the other hand, there is no better way of counteracting the bad effects - on the human body of a salt-meat diet than the use of lemon- juice and fresh green vegetables, which are rich in potash salts. The mineral matters found in different sorts of vegetable food are not always the same as those which form part of the body, their constituents being more or less re-arrahged and re-combined For salt a d a^er ^e*r consumption as food. A list of the matters ■"foods' most imPortant kinds of mineral matter or salts see Case 7. found in or taken with food may be fitly given here. 1. Common salt, chloride of sodium, appears to be essential to the life of the higher animals. Some plants contain little or the merest trace of it. Salt is diffused everywhere, and accumu- PHOSPHATES IN FOOD. 25 lates in the ocean, rain steadily washing it out of soils and rocks, and rivers then bringing it to the sea. Salt occurs as rock salt and in brine springs, both of which usually contain many other saline substances or impurities. By boiling down and crystal- lising its solution, salt may be purified and obtained of various degrees of fineness—bay salt, kitchen salt, and fine salt. Salt should be fine-grained, white and dry, and without bitter taste, the latter defect being due to chloride of magnesium. Common salt suffers certain changes in the human body, and is not merely taken to be excreted. Its chlorine helps to furnish the hydrochloric acid of the gastric juice, and the chlorine of the chloride of potassium found in red blood-corpuscles and in muscle. Its sodium forms part of the soda salts which are the characteristic constituents of the bile, and of the phosphate of soda of the blood. Salt is much used in the preservation of animal food; sometimes nitre is added as well.* For specimens 2. Potash salts, such as the phosphate, the car- of potash salts, 'r r' see Case 3. bonate, the chloride, and the nitrate, are either contained ready-formed in vegetable and animal foods, or are produced from other potassium compounds. Dry seeds, for in- stance, usually contain much phosphate of potash, while fleshy fruits and the growing parts of plants are rich in potash salts of organic acids, such as the oxalate, tartrate, citrate, and malate. These are changed by oxidation in the body into carbonate of potash, &c. &c. Potash salts in small doses are stimulating; in large doses they prove unmistakably poisonous. Nitrate of potash (saltpetre) is present in many plants, as lettuce and watercress. 3. Phosphate of lime, with small quantities of carbonate of For salts of lime and fluoride of calcium, is an essential mineral lime and mag- . . nesia, see Case 3. constituent of food. Phosphate of lime is well known as bone-earth; it is a white, earthy-looking substance, nearly insoluble in water. It is always associated in all three * In Case 7 is a small sample of the salt soil which occurs near the city of Mexico; also, salt obtained from this earth by extraction with water and boiling down. .26 HEAT-GIVERS IN FOOD. kingdoms of nature with the carbonate, fluoride, or chloride of calcium. It is contained in seeds and fruits chiefly, and is essential to the bones and teeth, which it hardens and strengthens. But phosphate of lime is doubtless concerned in the formation, not only of bone, but of most other tissues. Magnesia salts resemble and accompany lime salts. 4. Iron occurs in nearly all articles of food, though in very minute quantities. The ashes of all plants used for food contain For iron salts distinct traces of peroxide of iron. In vegetables it see Case 3. probably occurs in combination with organic acids. Milk has been found to contain 1 part of iron in 57,000 parts. 5. Of most of the acid constituents of the mineral nutrients we have already spoken; but the sulphates have not been mentioned. For sui hates ^ *s consid.ered that a part of the sulphuric con- see Case 3. stituent of the sulphates of the body is contained in the sulphates of drinking waters and vegetable food, but that some may be formed from the sulphur of the albuminoid and gelatinous matters consumed. One of the main functions of mineral nutrients is to aid in the transference, absorption, and elaboration of the oxidizable nutrients—somewhat after the same manner that a scaffolding aids the construction of a building. The same or similar offices are performed in plants by the mineral matters they contain. § 6.—Carbon-compounds or Heat-givers. The third group of nutrients contains a number of oxidizable carbon-compounds, the chief of which are starch, sugar, and fat. 1. Starch is, perhaps, the most important of the heat-givers •or force-producers in human food. It occurs abundantly in the . cereal grains, especially in rice, Indian corn, and wheat; about 15 per cent. may be obtained from potato tubers; it is also found in most leaves and stems, and in many succulent fruits. Starch See Drawings occurs in peculiar forms called granules, which are uics. often quite characteristic of different plants. Starch STARCH. 27 is a white, glistening powder, insoluble in cold water, but nearly completely dissolved by hot water. Its solution, when cold, becomes an intense blue when a solution of iodine is added to it . Starch forms about 83 per cent. of the whole weight of tapioca, from the root of Manihot utilissima and M. a/pi, the mandiocca or cassava plants, natives of South America, and belonging to the Euphorbiacese, or Spurge order. The roots of the bitter cassava For tapioca and (M. utilissimd) contain prussic acid as well as sk Case 8. * starch, the former being separated by washing the grated roots, and allowing the starch granules to settle. Another well-known starch is that which goes under the name of arrow- root. It is obtained chiefly from the the rhizome, or root-stock, of Maranta arundinacea, a native of the West Indies, largely culti- vated in Barbadoes, St. Vincent, and Bermuda. Tous-les-mois is another starch, obtained from the tubers of Canna edulis. Sago For arrowroot is likewise a starch, mainly produced by the sago Case 9.' palms (Sagus rumphii and S. lavis). The trees are felled, split, and the starch washed out from the central parts. In the Moluccas sago cakes are a common article of food. In Ceylon and some parts of the East Indies a coarse sago is made from the nuts of Cycas revoluta, &c. The most common starches used in England as food are those from the tubers of the potato, from wheat, from rice, and from Indian corn, this latter often going under the name of corn-flour. Portland sago, or Portland arrow- root, is a starch obtained from the tubers of a species of arum; while salep or saloop, once largely consumed, and still used in For saiep see Turkey and the East as food in Europe, is a starch Casc *• derived from the tubers of eleven kinds of Orchis, such as O. mascida, O. maculata, and O. morio. The salep sold in London mostly comes from Smyrna. Inulin, from the roots of elecampane (Inula Heleniuni) and Jerusalem artichokes (Helianthus tuberosus), has the same com- position as starch, and closely resembles it in most of its pro- perties. 28 STARCH. The following table gives the quantities of starch in i00 lb. of several kinds of vegetable products and prepara- tions :— lb. Sago, tapioca, arrowroot, corn- flour, maizena • - - 83 Pearl barley - - - - 76 Rice 76 Fine wheaten flour - - - 74 Wheat 71 Rye 71 Buckwheat, without husks - - 64 Maize ..... 64 lb. Scotch oatmeal - - - 63 Millet, without husks - - 61 Peas 51 Haricot beans - - - - 49 Wheaten bread - - - 48 Wheaten bran ... - 44 Potatoes 15 Parsnips ----- 3 Vegetable marrow c4 Some of these numbers include with the starch small quantities of dextrin, sugar, and gum—substances which subserve the same purposes in the animal system. Starch, like all the compounds of the group of nutrients now under consideration, contains carbon, hydrogen, and oxygen only. It is never met with in commerce quite pure and free from moisture—arrowroot, for instance, containing from 12 to 16 per cent. of water, with traces of mineral and nitrogenous matters. Neither arrowroot nor any other starch can furnish the materials for the building up and repair of flesh or muscle; it is, how- ever, next to oil and fat, the most concentrated, heat-giving, and force-producing of all the nutrients. To be digested, starch must be dissolved, or at least softened. These changes are effected by boiling in water, or baking in the presence of moisture. Thus the digestion of starch may be said to com- mence in its preparation by cooking. It proceeds further through the action of the saliva during mastication, a peculiar ferment called ptyalin which exists in the saliva being capable of changing starch into glucose, a variety of sugar. In the stomach, such parts of the starch as have escaped previous change do not alter much; but these are finally transformed into sugar in the small intestine; thence the sugar is absorbed into the blood. SUGAR. 29 For specimen. Dextrin has the same composition as starch, Casedeofrinpoti" but it is soluble in cold water. It may be made preparations. by n£ating starch tQ ^o Fah , and by actmg upon it with a small quantity of malt flour, or of nitric or sulphuric acid, for a short time. Thus prepared, dextrin often goes under the name of British gum. It is at least of equal value with starch as a food, and requires less alteration to change it into sugar previous to its absorption. It occurs to a con- siderable amount in bread, especially in the crust, in biscuits, and in some prepared infants' foods, as those of Liebig and Nestle. Beer contains a little dextrin. Starch, during digestion, is partly and temporarily changed into dextrin. 2. Sugar is distinguished from starch by its solubility in cold water and its sweet taste. Its composition is slightly different also. But there are several kinds of sugar, which must be con- sidered separately. For specimens The best known sort of sugar is that which Cases 10 t'o 16. is sold under the name of cane sugar. Much of that consumed in England is derived from the sugar beet, a variety of Beta vulgaris, a plant believed to have originated in the sea beet . The roots of this plant, when of good quality and small size (2 to 3 lb.), contain from 10 to 13 per cent. of a sugar identical with that of the sugar-cane. Sugar beet is largely grown in France, Belgium, and Germany. It has also been raised successfully in England on a small scale. The oldest and best-known source of this kind of sugar is the sugar-cane {Saccharum officinarum), a handsome plant of the grass order, a native of Southern Asia. It grows to the height of 12 or even 15 feet. It has been long cultivated in most parts of tropical and sub-tropical Asia, and in the islands of the Indian and Pacific Oceans. From India it was brought to Europe, many centuries ago, and was afterwards introduced to and largely grown on the American continent. Our present supplies of cane sugar come from Brazil, Mauritius, and the 30 SUGAR. West Indies. To prepare this sugar the canes are cut down when they begin to flower, close to the ground, the juice thoroughly expressed from them, clarified and boiled down. "Raw" or "brown" sugar is the first product, along with molasses (except where the ingenious process called concreting is adopted, when no molasses are formed). By refining brown sugar—that is, re- crystallising and purifying by the aid of charcoal and lime, &c.— cleaner, purer, and drier crystalline sugars are got, and it is in these later refining processes that treacle and golden sirup are obtained. These sirupy liquids contain about 65 per cent. of uncrystallisable sugar, with some saline matters and other impurities, while the remainder is water. Sugar-candy is the purest form of sugar; white loaf sugar comes next; then the pale, dry, large-grained crystallised sugars; while all the coloured moist sugars are of inferior purity, invariably containing not only water and uncrystallisable sugar, but also mineral and organic compounds. They are not unfrequently largely infested by a small insect, the sugar-mite (Acarus sacchari), many thou- sands of which have been frequently detected in a single pound of brown sugar. Whatever may have been the case formerly, sugar is not now adulterated, save, perhaps, with the kind of artificial sugar called glucose; but sugar is often insufficiently purified. Many other grasses besides the sugar-cane contain large pro- portions of sugar. For instance, sugar has been made from the stalks of maize or Indian corn, cut just before flowering. The Chinese sugar-grass, or sugar-millet (Sorghum saccharatum), is another sugar-producing plant. It has been introduced into and successfully grown in France, Italy, Southern Russia, the United States, and Australia. A closely-allied species, called Imphee, is grown by the Zulu Kaffirs, and yields not only sugar in its stems but much valuable starchy food in its seeds. The seeds, indeed, of all the kinds of Sorghum are very nutritious,, and are used, amongst other purposes, for feeding SUGAR. 31 poultry. All the derivatives of sugar—molasses, rum, wine,, vinegar, &c.—have been obtained from the sugar-grass; the manufacture of sugar, &c., from this plant in the States is, how- ever, declining. Another source of sugar is the sugar maple, Acer saccharinum, with other allied species, as A. pennsylvanicum, A. negundo, and A. dasycarpum. These trees of Canada and the northern United States contain a sap in which about 2 per cent. of cane sugar occurs. In the spring the sap is collected and boiled down. It is stated that 1,546,000 lb. of maple sugar were produced in Pennsylvania in 1870. Jaggary is a sugar obtained chiefly from the flowering shoots of two Indian palms, Phanix sylvestris and Caryota urens. But many other palms, as the coco-nut and the Palmyra palm, yield abun- dance of a sugary juice known as "toddy" when freshly drawn or fermented, and "arrack" when distilled. From these palms, and from the Arengo saccharifera and Nifia fruticans, palms of the Indian Archipelago, as well as from the date palm, Phanix dadylifera, jaggary sugar is made. It has been stated that 700,000 tons of sugar, from beet-roots, are annually prepared in Europe, an amount which is about half of the total European import of sugar from the sugar-cane. Many other plants besides those named above contain cane- sugar. The expanding buds of trees, as of the birch (Betula alba), yield a sap which by fermentation becomes birch wine, formerly made to some extent in Scotland. The following list gives, approximately, the proportions of ordinary sugar contained in a few important vegetable products, &c Sugar (Saccharose or Sucrose) in 100 lb. of lb. Rv Dried carob beans - 5' Chinese sugar-grass - 9 Sugar-cane juice - 18 Maize-stem juice - - 7 Beet-root - - 11 Sugar maple sap - - 2 3* SUGAR. It may be added that the solubility of cane sugar is such that two ounces require but one ounce of cold water to dissolve them. Sugar has the specific gravity i *59. It is not absorbed into the blood as cane sugar, but is previously converted, both by the acids of the gastric-juice and by the nitrogenous matters of the food during digestion, into the variety of sugar called grape sugar, or glucose. Sugar is extensively used to preserve fruits. Fruits boiled with sugar yield jams, preserves, and fruit jellies. Many fruits may also be preserved whole in sirup of sugar, or they may be subsequently dried, when they become "candied" or "crystal- lised."* Grape sugar comes next in importance to cane sugar. Just * Collections of fruits preserved by the aid of sugar are shown. The following specimens of sugar are shown in Cases 10 to 18 :—Raw sugar of the crop of 1871, manufactured at the Colonia de San Pedro Alcantara, Malaga, Spain.—A series of raw and refined sugars from various parts of the world, illustrating the process of sugar-refining; also a diagram of a sugar-refinery.—Two specimens of sugar-cane grown on the Grove Estate, Montserrat, West Indies.—A series of specimens of the various products ob- tained in the manufacture of sugar from sugar-beet, from Valenciennes.— White and brown sugar from Formosa.—Confectionery: Almonds, comfits, candy, and a variety of table ornaments made of sugar.—Various specimens of ornamental sugar-work, with samples of the materials used in making the same.—A series of fruits preserved with and without sugar, sugar confectionery, ornamental sugar-work, &c.—Lozenges of different sorts.—Samples of maple sugar.—Samples of raw and refined sugar from Cuba, Penang, Jamaica, Porto Rico, Mauritius, Bengal, and Demerara; also refiners' sugar, termed "pieces," and refuse sugar from refineries.—A collection of raw and refined sugars from the French colonies of Reunion, Martinique, Guiana, Guadaloupe, Mayotte, Tahiti, and Cochin-China.—Also a series of samples of raw sugars from Java. —Samples of raw sugar from sugar-canes grown in the neighbourhood of the Clarence River, New South Wales, Australia. The specimens named above illustrate not only the numerous sources of the chief kind of sugar, known as sucrose or saccharose to scientific chemists, but they also show to some extent the processes of the manufacture, and the by- products obtained in the treatment of the raw material. Many of the uses to which sugar is put, such as the preservation of fruits, the manufacture of lozenges, confectionery, cordials, sirups, and wines, may also be studied in the collection. GRAPE SUGAR. 33 as the latter sugar is found in many plants besides the sugar-cane, so grape sugar is abundantly distributed through the vegetable kingdom. More than this, it may be readily made from starch, dextrin, and cane sugar, by the action of weak acids. But, perhaps, a still more remarkable mode of obtaining this sugar is by means of the action of strong sulphuric acid or oil of vitriol, upon cellulose, the compound which forms the main substance of paper, cotton, linen rags, and some woods. Thus it happens that all these substances are now used for the manu- facture of grape sugar, or glucose as it is called. This glucose, being immediately fermentable, may be used to strengthen the worts in brewing, and for the direct production of alcohol. So spirit may be made from old rags and waste pawnbrokers' tickets! Grape sugar, or glucose, exists in three forms at least. Two Hon from o^ t'lese' dextrose and ljevulose, make up the main and^iiS'b? bulk of honev ,* the third, maltose, occurs in malt, feerentfflowersfu a sprouted grain. The variety of glucose called shown m Case 20. dextrose exists largely in sweet fruits, as the grape, and crystallises out in hard warty masses when ripe grapes are dried, as in the case of raisins and French plums. The lsevulose of honey and of acid fruits will not crystallise, but can only be dried up into a glassy or resinous mass. These sugars, as well as maltose, are less sweet than cane sugar. They are immediately absorbed into the circulation when taken into the stomach. They are valuable nutrients, especially for the young, but may give rise in some disordered conditions of the stomach to an unusual pro- duction of lactic acid, two proportions of which are producible from one proportion of any of these sugars. The quantities of glucose or similar sugars present in a few * In Case 20 will be found a series of specimens of honey from France and French Colonies. Also Russian specimens of honey, collected by bees from differsnt plants, chiefly wild. 34 OILS AND FATS. important vegetable products may be seen in the following table :— Glucose (that is, Dextrose, L/evulose, Maltose, &c.) in ioo lb. of lb. Honey, or nectar of flowers - 80 Dried Turkey figs - - - 57 Grapes - 13 lb. Tomatoes - - - - - 6 Malted barley - - - - 5 Cucumbers.... - 2 Milk sugar has the composition of cane sugar, but many of the properties of grape sugar, into which it is converted when consumed as food: it also yields butyric and lactic acids. Milk sugar has comparatively little sweetness, and is less soluble than the pre- viously-named sugars: its crystals contain one proportion of water of crystallisation. This sugar is often called lactose, and is found as one of the characteristic ingredients of the milk of mammals. In 100 parts of cows' milk there are over 5 parts of lactose. A few other sugars of minor importance remain to be men- tioned. There is Inosite, or muscle sugar, which has been found in the human body, in ox brain, and extract of meat. There is Mannite, the sugar-like substance of manna, a substance pro- duced by several kinds of ash, chiefly by Fraxinus omits. We Preparations have also the sweet substance, glycyrrhizin, found Case 19. in the liquorice plant (Glycyrrhiza glabra), which is used as a sweetmeat and flavourer. Pomfret, or Pontefract, cakes are made from native-grown liquorice, the plant being cultivated at Pontefract, in Yorkshire. It is doubtful whether the last- named sugar-like substances, mannite and glycyrrhizin, are true nutrients. No experiments have been made with these compounds, nor with the sugar-like bodies from some seaweeds, pine-needles, &c . &c., which have been found to differ from the well-known sugars already noticed. 3. The Oils or Fats form a very distinct and important section of the group of heat-givers. Like starch and sugar, they can form OILY SEEDS AND FRUITS. no muscular tissue, but their power of maintaining the heat and activity of the body is nearly 2 y2 times that of the starchy nutrients. So far as their feeding properties are concerned, oils are identical with fats, the distinction between the substances thus named referring chiefly to their condition of liquidity or solidity. Wax, on the other hand, though probably of similar value as a nutrient, differs somewhat from oils and fats, notably in not yielding glycerin. Case 21 con- Oils and fats may be considered as formed from tains specimens - . - . - , . . of oils and fats. a fatty acid on the one hand, and glycerin on the other. Indeed, if three proportions of one of these acids, say palmitic acid, be heated with one proportion of glycerin in a closed tube, these substances disappear, palm oil or palm fat and water being produced. This palm fat, which is a glyceride, is called palmitin, and forms, with two similarly-constituted com- pounds, known as stearin and olein, most of the important fixed oils and fats, whether vegetable or animal. In many of these, however, other glycerides occur, as small quantities of butyrin and caproin in butter. The quantities o .oil or fat contained in some important vege- table and animal products are quoted in the following table:— Oil or Fat in 100 lb. of Palm-nut (pulp) Brazil-nuts (seeds) Almonds (kernels) Ground-nut (seeds hypogma) Sesame (seeds) - Palm-nut (kernels) Poppy (seeds) - Olives (kernels) - Cacao (whole seeds) Olives (pulp) Linseed - of Arachis lb. 72 67 53 52 Si 47 45 44 44 39 38 Coco-nut (kernels) Hemp seed Walnuts (kernels) Gold of pleasure (seeds) Cotton (seeds) - Sunflower (seeds) Fresh Scotch oatmeal Maize (seeds) Millet (seeds) Wheaten bran - Peas (seeds) Wheaten flour - lb. 36 32 32 32 24 22 IO 5 5 4 3 1 D 2 GUM, ETC. 37 Besides its great use as a giver of heat, and therefore of mechanical force or energy, fat performs an important function in the body as the chief material of the adipose tissue. This fatty layer, where it exists beneath the skin, keeps in the warmth of the body; while such stores of fat as exist in this form throughout the organism may be re-absorbed into the blood, and keep up the animal heat and activity during abstinence from food. Appendix to Group III.—In the different parts of plants which are eaten as food there will be found many oxidizable or com- bustible carbon compounds which are neither starchy, saccharine, nor oily. As some of these compounds are known to be closely related to starch or sugar, and, indeed, have the same com- position in 100 parts, there is some ground for believing that they may serve the same purpose in the animal economy. And this conjecture is confirmed by many experiments, especially upon the lower animals. Case 3. Gum, met with in many trees, as the apple, the plum, and some sorts of acacia, is near cane sugar in its com- position. It is usually accompanied by a little lime and potash, and is found dissolved in the juices of many stems and fruits. Gum arabic and gum Senegal are two good examples of this substance. Gum arabic is considered to be a mixture of arabate of lime and bassorin. Case 3. Mucilage is found in the bulbs of the onion, in quince seeds, and in linseed. It forms a jelly with water, but does not dissolve to a thin liquid like gum arabic. As the mucilage of linseed suffers changes resembling those of starch when the seed is allowed to sprout, it may be that it undergoes solution and absorption in the body also. Case 3. Pectose is found in many roots, as the turnip, and in many fruits as the pear and peach, especially while they are unripe. When boiled with water, it rapidly changes into vege- table jelly, to one variety of which the name of pectin has been given. Similar changes occur in the ripening of fruits. The 38 CELLULOSE. firmness of various jams and preparations of fruit—as damson, plum, and red-currant jelly—is due to substances belonging to the pectose series. In the present handbook we have given these substances under the single name of "pectose;" partly to avoid needless complexity, and partly because of the imperfection of our methods of analysis, which do not yet enable us to give exacter particulars. There is good reason for believing that the substances belonging to the pectose group are capable of digestion and absorption in the human body. Case 3. Cellulose has the same composition as starch and dextrin, and is nearly related to these compounds. It is, how- ever, insoluble even in hot water. Cellulose is nearly pure in cotton, and in the cell-walls of many of the fruits, stems, and roots which are eaten as food. It is doubtful whether cellulose is digestible in the human organism, though it has been shown that it is digested by herbivora. But cellulose varies much in softness, texture, &c., and it is very likely that newly-formed cellulose may be changed and absorbed in part in the digestive process, while the firmer and older tissues containing the same substance may not be altered. These firmer tissues are, more- over, often of a different composition, for the cellulose is asso- ciated in many of them with certain yellowish substances, which are richer in carbon than cellulose, though their exact nature is not yet made out. It will be convenient to group them together under the name lignose. Lignose is specially abundant in hard woods, like box, while cellulose makes up the greater part of soft woods, like pine. The fruit of the apple contains a good deal of cellulose and a mere trace of lignose; while in wheaten bran both compounds are abundant. We are now in a position to consider the relative values of the several heat-giving and force-producing nutrients which have been described; but a few words may be first introduced as to some points of difference between these compounds. The rate at which these different heat-givers are digested and 4o FLESH-FORMERS. force within the body, but the hydrogen, or most of it, may be similarly used. A good notion of the relative values of the above-described four classes of carbon-compounds in their heat- giving and force-producing capacity may be gathered from the results obtained in Dr. Frankland,s experiments. He burnt these compounds in oxygen, and determined the actual amounts of heat they severally set free. Now, we know that heat and mechanical energy or work may be changed the one into the other. And it has also been proved that heat and work have a definite quan- titative relation to one another, so that the heat required to warm i lb. of water i0 Fah. may be changed into the amount of mechanical power requisite to lift 772 lb. 1 foot high. Thus, we may express the total heat producible by the complete combustion or oxidation of 1 lb. of these food-constituents in the form of so many pounds or tons raised 1 foot high :— Tons raised 1 ft. high. Starch (arrowroot) ...... 2,427 Cane sugar ....... 2,077 Grape sugar 2,033 Oil (cod-liver) 5,649 According to Helmholtz, the greatest amount of mechanical work, outside the body, which a man could be enabled to perform by the combustion within the body of 1 lb. of each of the above substances would be about one-fifth of the amount given in the above table. This subject has been already referred to on p. 2, and will be again the occasion of some further remarks when the questions of the daily supply of food and of different dietaries are under discussion. § 7.—Nitrogenous Compounds or Flesh-formers. The fourth group of nutrients in food is marked out from those previously considered by the presence of the element nitrogen—the element which forms 79 parts, by measure, in 100 ALBUMEN. 41 of common air; which is present in nitre, nitric acid, and ammonia; and which is so much more abundant in animals than in vegetables. These nitrogenous compounds have been variously termed— Albuminoids, Proteids, Flesh-formers. When, in the following pages, we are speaking of the con- stituents of different foods in their relations to the nutrition of the body, the term "flesh-formers" will be used; when these com- pounds are referred to from a merely chemical point of view, they will be described under the general name of "albuminoids," except in those instances where the prevailing kind of albuminoid in any food-stuff is characteristic and well known, when its specific name will be used. Thus the chief albuminoid in wheat grain will be called fibrin, on account of that name having been assigned to that one of the three kinds of albuminoids which specially abounds in the cereal grains. So casein, another kind of albuminoid, will be given in the analysis of peas, and albumen in that of the turnip. Where the nature of the albuminoid is not precisely known, the general term "albuminoids" will be employed. And where the nitrogenous matter is not proved to be actually and truly albumi- noid, then it will generally be described as "nitrogenous matter" simply. But it is time to give an account of the several members of this group. Case 3. 1. Albumen, the main solid constituent of white of egg, gives its name to the whole group. The blood of many animals contains this component. It is a common ingredient of most vegetable juices, and is found in considerable quantity in certain seeds. It exists in two states, one soluble in water, the other insoluble. The soluble form may be easily changed into the in- soluble by heating its solution to about 1200 Fah., or by the addition of nitric acid. It is considered by some physiologists GELATIN. 43 They are probably turned to some account in the human body, but eveiy constituent in that complex organism may be made, without their aid; for persons living wholly on vegetable foods do not consume these substances at all. These nitrogenous nutrients are familiar to us under such names as gelatin and isinglass (which are indeed the only nitrogenous nutrients separately sold), but there are other varieties of them, which should be briefly noticed here.* Case 3. Ossein is that constituent of bones to which their strength and elasticity is due; it is found also in connective tissue. It is insoluble in cold water and weak acids—indeed the best way of preparing ossein is to place a clean piece of fresh ox or sheep bone in a mixture of 1 part of hydrochloric acid and 9 of water. After some time all the earthy matter of the bone will have been dissolved out, nothing being left but an elastic mass of ossein (with a little fat), retaining the shape of the original bone. Ossein contains rather less carbon, and rather more nitrogen, than the true albuminoids. Though insoluble in cold water, it is slowly dissolved by boiling water, becoming thereby converted into gelatin, a substance of the same composition, but slightly different properties. The change of ossein into gelatin takes place more readily when the water in which the bones are boiled is heated a few degrees above the boiling-point. This can be done by preventing the escape of steam—that is by heating the bones and water under pressure. The simple arrangement known as Papin's Digester answers this end perfectly, and enables * Isinglass is most prized when obtained from the sound or swimming bladder of the sturgeon (Acipenser of several species). It is chiefly imported from Russia. Varieties of this substance, illustrating its qualities, manufacture, and application to ornamental purposes, are exhibited.— Ivory dust and shavings are sometimes used for making jellies.—Samples of these substances and of others used for similar purposes are shown in the collection.—Samples of jelly made from calves' feet, and flavoured with various fruits. f 44 PEPSIN. the full amount of nutritive matter to be dissolved out of bones which are intended to be used as stock for soups. Many other substances besides bones may be made to yield gelatin by long boiling with water. These are tendons, con- junctive tissue, calves, feet, fish scales, stag,s horn. Isinglass, though not actually gelatin, is rapidly transformed into that sub- stance by boiling water, yielding one of the purest and most characteristic forms of gelatin known. Isinglass consists of the membrane of the swimming bladder of the sturgeon (Acipenser of various species). Much so-called isinglass is merely gelatin prepared from some of the materials we have named, or from the cuttings of parchment and vellum. Thus "Warranted Calves' Foot Jelly" may have been made from old legal documents! Gelatin sometimes contains sulphuric acid. Case 3. Cartilage does not yield gelatin when boiled, but an analogous substance called chondrin. This material contains less nitrogen (4 per cent . less) than gelatin; it possesses somewhat different properties, and yields different products. Elastin and keratin, and similar matters from elastic tissue, skin, epidermis, &c., are included in the present sub-group; they are of small or doubtful value as nutrients. They, as well as mucin, the nitrogenous constituent of mucus, are almost entirely unacted upon by the gastric juice. We are now in a position to compare the relative values of the several flesh-formers and allied compounds included in the nitrogenous nutrients. The albuminoids suffer no chemical change during masti- cation. But when they come in contact with the gastric juice in the stomach, their digestion commences. This juice contains two active ingredients, an acid or a mixture of acids, together with a neutral nitrogenous substance called pepsin. This pepsin is a digestive ferment; by its aid, if acid be present and the temperature be suitable (about 980), albuminoids are all converted into substances bearing the name of peptones. NITROGENOUS NUTRIENTS. 45 These are all soluble in water, and are not removed from the solu- tion by acids, alkalies, or salts; they are all soluble, even in alcohol, if not very strong; and they are diffusible. Casein before it becomes a peptone, is curdled; vegetable casein is rapidly changed and dissolved by gastric juice deprived of its pepsin. Fibrin, whether animal, as that in muscular flesh, or vegetable, as the so-called gluten of wheat grain, is rapidly broken up by the gastric juice, swelling up, and finally becoming a ropy, opaline liquid. Albumen, when soluble, is transformed into peptones without being previously curdled by the gastric juice; when insoluble, it is more slowly acted upon. The conversion of albuminoid nutrients into peptones, which can be absorbed into the circulation, is completed in the intestine, where several secretions aid in the processes of change. Little is known about the digestion and uses of gelatin and allied compounds. It is, however, certain that solution of gelatin, after having been acted upon by gastric juice, no longer solidifies to a jelly on cooling. Before these compounds can enter the circu- lation, they must be altered, since when introduced into the blood artificially they are excreted unchanged. The composition of the several nitrogenous nutrients is com- pared in the following table, where the weights of the carbon, hydrogen, nitrogen, sulphur, and oxygen in i00 parts of each important variety are shown :— Albumen. Fibrin of blood. Fibrin of muscle Carbon 53*5 - 527 54-0 Hydrogen ■ 7-0 - 6-9 • 7*3 Nitrogen 15 5 - 15-4 - i6-1 Sulphur r6 - I *2 i-1 Oxygen 22-4 - 23-8 2i-5 Casein. Gelatin. Chondrin 53-8 - 50-8 50-0 7-1 • 7-i • 6-6 157 ■ 18-3 • '4-5 09 - o-6 0-4 23 *5 • 23-2 28-5 Thus the actual weight of carbon in 1 lb. of any average albuminoid may be set down as 8 oz. 245 gr. Before con- sidering what amount of work or actual energy this carbon and the hydrogen present correspond to, it would be as well to state 46 USES OF ALBUMINOIDS. the various uses to which the albuminoids are put in the human body. For they serve— 1st. For the building up and repair of the nitrogenous tissues of the body, espe- cially of the basis of flesh, that is, muscular fibre. As no -other ingre- dient of food can fulfil this office, it is right that the albuminoids should bear the expressive name of flesh-formers. 2nd. The albuminoids contain 10 per cent, more carbon than starch and sugar, and some part at least, though never the whole, of this carbon is available as a source of heat and work in the body, especially when the supply of the usual heat-givers is deficient. 3rd. The albuminoids serve for the formation of a large number of nitrogenous substances which are found in most parts of the body, but especially in brain and nerve-substance. These compounds are rich in nitrogen, and sometimes contain sulphur and phosphorus as well. 4th. The albuminoids may contribute fat to the body. It is easy to obtain artificially the main constituents of fat by the action of chemical agents upon the albuminoids, compounds rich in nitrogen being formed at the same time: similar changes may and do occur in the body. The variety of offices performed by the albuminoids, when compared with the carbon compounds called heat-givers, which have been studied in the preceding section, is due in part to their complex character. This complexity arises from two causes— for these compounds are made up of 5 different elements instead of 3, while a very much larger number of atomic proportions of their elements are present than is the case with starch—probably several hundreds, instead of 21. But another reason for the variety of uses to which the albuminoids are put in the body arises from the presence of nitrogen, an element which confers a character of instability, of proneness to change, upon most of the compounds of which it forms part. The processes of life and growth, as well as of putrefaction and decay, occur in the presence of nitrogen compounds. There is no need to enlarge further now upon the 1st, 3rd, and 4th items of service named in the foregoing list as rendered by the albuminoids. But it may be useful if we introduce here a few remarks as to the relation of the albuminoids to the per- FLESH AND FORCE-PRODUCERS. 47 formance of work. It used to be thought that work—hard bodily exertion, as in ascending a mountain, in pedestrian feats, or in hammering iron—was done by the actual destruction of muscular substance itself. If this be true, we ought to find the proof of that destruction of muscle in an excessive excretion of the waste nitrogenous product known as urea, which is got rid of by the kidneys. But this is not the case, the excretion of urea not corresponding in amount to the work done. Yet during the per- formance of hard work an ample supply of albuminoids is found to be needed, probably by reason rather of the rate than of the extent of chemical change which violent exercise and hard work cause in the body. As to the function of nitrogenous matter in furnishing supplies of heat, and, therefore, of actual energy to the body, we have to remark that Dr. Frankland has experimented with pure albumen. Burnt in oxygen it set free an amount of heat which may be expressed in this way:—1 lb. of this nitrogen-compound, during complete oxidation, liberates an amount of heat corresponding to Tons raised i ft. high. Albumen --.-.--- 2,643 At first sight it would seem from this number that the albu- minoids are more efficient force-producers (when so used in the body) than most of the true heat-givers, whose main office it is to furnish heat and energy to the system. But a special deduction must be made from these figures, for when nitrogenous matters are oxidized in the body, a small portion of the carbon and hy- drogen which they contain is carried away, with its potential energy unexpended, in the urea, &c., formed in the organism and excreted by the kidneys and intestine. Now, by determining the amount of potential energy remaining in that amount of urea which 1 lb. of albumen may be assumed to yield, Frankland concluded that a deduction of one-seventh must be made from the above number. Thus the available heat set free from the 48 DAILY FOOD. oxidation of i lb. of albuminoid matter within the body cor- responds to 2,266 tons raised 1 ft. high, not to 2,643 tons. Albumen, then, ranks between starch and sugar as a heat-giver and force-producer. It may be well to remind our readers once more that only about one-fifth of this energy at the utmost can be available for work outside the body (see p. 40). § 8.—A Day's Ration. Thus far we have considered the uses of food, the composition of the human body, and the several compounds which are neces- sary for its nutrition. Let us now go on to study in some detail a day's ration—its composition, its work, and the changes which it undergoes in the body. The daily supply of food and the daily waste of the human body have been often made the subject of experiment. It will be understood at once that even with healthy adults the amount of food required will vary according to many circumstances. To begin with, there are peculiarities belonging to each individual; then there are differences in the amount of work performed; the heat or cold of the weather, as well as the condition and quality of the several kinds of food taken—all these things will influence the total quantity of food required in the twenty-four hours, as well as the proportions of the chief components which it should contain. But we may arrive at something like an average daily diet by taking the case of an adult man in good health, weighing 1541b., and measuring 5 feet 8 inches in height. Simply to maintain his body, without loss or gain in weight, his ration of maintenance, or food, during the twenty-four hours should, under ordinary conditions, contain at least something like the following proportions and quantities of its main ingredients :— 50 DAILY FOOD. together, even in the right proportions, the mixture would not be a perfect food, for it would be wanting in at least one particular— it would not be pleasant in taste. Our food must be palatable, that we may eat it with relish and get the greatest nourishment from it. The flavour and texture of food—its taste, in fact— stimulates the production of those secretions—such as the saliva and the gastric juice—by the action of which the food is digested or dissolved, and becomes finally a part of the body, or is assimilated. As food, then, must be relished, it is desirable that it should be varied in character—it should neither be restricted to vegetable products on the one hand, nor to animal substances (including milk and eggs) on the other. By due admixture of these, and by varying occasionally the kind of vegetable or meat taken, or the modes of cooking adopted, the necessary con- stituents of a diet are furnished more cheaply, and at the same time do more efficiently their proper work. Now, if we were to confine ourselves to wheaten bread, we should be obliged to eat, in order to obtain our daily supply of albuminoids, or " flesh- formers," nearly 4 lb.—an amount which would give us nearly twice as much of the starchy matters which should accompany the albuminoids—or, in other words, it would supply not more than the necessary daily allowance of nitrogen, but almost twice the necessary daily allowance of carbon. Now, animal food is generally richer in albuminoid, or nitrogenous constituents, than vegetable food; so by mixing lean meat with our bread, we may get a food in which the constituents correspond better to our requirements; for 2 lb. of bread may be substituted by 12 oz. of meat, and yet all the necessary carbon as well as nitrogen be thereby supplied. As such a substitution is often too expensive, owing to the high price of meat, cheese, which is twice as rich in nitrogenous matters (that is flesh-formers) as butchers' meat, may be, and constantly is, employed with bread as a complete diet, and for persons' in health, doing hard bodily work, it affords suitable nourishment. Even some vegetable products, rich in A DAY,S RATION. 51 nitrogen, as haricot beans, may be used in the same way as meat or cheese, and for the same purpose. Such a mixed daily diet as we have been referring to might be furnished by the following foods if consumed in the quantities here given :— 1. Bread - - - - 18 2. Butter - - - - i 3. Milk ... - 4 4. Bacox .... 2 5. Potatoes- - - - 8 6. Cabbage ... 6 7. Cheese .... 3^ 8. Sugar - 1 9. Salt .... o)( 10. Water, alone, and in Tea, Coffee, Beer - - - 66# , Altogether these quan- tities will contain about lib. 5 J£ oz. of dry sub- stance, though they weigh in all bib. 14^ oz. It will be seen that the weight of this daily ration exceeds by 1 oz.—even when the solid matter contained in beverages is omitted—that given before (on p. 49); this excess is mainly owing to the fact, previously mentioned, that in all articles of food actually used there are small quantities of matters (cellulose, &c.) which cannot be reckoned as having a real feeding value. And it must not be forgotten that the several common proximate principles which can and do supply the greater part of the heat of the body have not all the same value for such a purpose. Of starch and dextrin we should require rather less than of sugar for the production of the same amount of force, while 1 oz. of fat or oil will go nearly as far as 2^£ oz. of starch. This allows of much variation in our daily food, since we may replace, to a certain extent, a portion of the fat in our rations by its equivalent quantity of starch or dextrin or sugar—or we may diminish the starch and increase the fat. In the former case the dry substance of our food might come to weigh 4 or 5 oz. more than the 20}^ oz. mentioned before; in the latter case it would weigh less. e 2 52 DAILY WASTE OF THE BODY. Suppose, for instance, we were to take, daily, no more than 3 oz. of fat in any form, we should have to add about 2^ oz. of starch or sugar to compensate for this reduction, thus con- suming 14 oz. of the latter instead of n^. Here it may be asked—" Which of the articles of the above mixed diet give the several components of food which we require each day?" A sufficient answer to this inquiry may be gained by referring to the composition of the several articles of food named, as given in this Guide, and as shown in the Cases of the Food Collection. Here it will be enough to state that the bread consumed chiefly supplies starch, but along with this a good deal of albuminoid substance; the milk gives fat, albuminoids, and a sugar, having nearly the same value as starch; the cheese contains much fat and albuminoid substance; the bacon and butter chiefly furnish fat; while the other articles in the list either give further supplies of these food-components, or else the mineral matter or salts which are required. The first seven articles in the list will likewise contain about 1 lb. (>% oz. of water, which, with that supplied in various beverages, will furnish the 5 lb. 8^4 oz. daily necessary. Before considering different foods and dietaries, it will be as well if we now pay some attention to the waste of the body. We will endeavour to answer the question: What becomes of our food after it has been digested and assimilated, and has done its work in our bodies? We have seen what is the amount, and what the composition of the daily in-goings, or food; let us see what is the amount and the nature of the out-goings, or waste. Before we can make the comparison, we must recur for a moment to the general nature of the final change which food undergoes in the body. That change, we have before shown, is in the main one of burning, or, as it is called in chemical language, oxidation. It is the uniting of certain elements contained in the food—chiefly carbon and hydrogen—with oxygen, brought into the lungs by the act of breathing. The air, then, is, in a sense, part of our food, DAILY SUPPLY OF THE BODY. S3 and forms a large part of the daily in-come of the body. As the oxygen taken in unites with the carbon and hydrogen of the food, we must not expect to find that the proximate principles consti- tuting the main mass of our daily food will be found in any quantity in the daily waste. How then can we compare the in-goings and the out-goings? Why, by considering the amounts of the chief elements of which the proximate principles consist, and comparing them with the amounts of the same elements which are discharged in the oxidized waste of the body. In accordance with this way of representing the facts, we now give in a tabular form the daily supply and waste of the human body. First, we set down the weight of the several elements which make up the necessary daily food or Case 23. Daily Supply. lb. oz. gr. lb. oz. gr. Oxygen in the air breathed - - - 1 10 115 Oxygen in starch, albuminoids, and fat - o 7 3 70 Total oxygen .... 2 2 47 Carbon in fat, starch, albuminoids ..... 09 400 Hydrogen in the same ....... oil 70 Nitrogen in albuminoids ------- 00 291 Common salt ---.-.--. 00 325 Phosphates, potash salts, Sec. ...... 00170 Water 58 320 Total daily supply ... 87 410 It will be here seen that four elements only are set down in the separate form as elements in the above table. These are oxygen, carbon, hydrogen, and nitrogen, so far as these elements enter into the composition of, that is, form part of, the proximate prin- ciples which we consume as our food, and which we change into new compounds in the body. The salt and other minerals of the food, together with the water we consume, are not so changed, and therefore these substances are not resolved into their elements in the table of Daily Supply, nor in that which follows, repre- senting /"" 54 DAILY WASTE OF THE BODY. Case 23. Daily Waste. lb. or. gr. lb. oz. gr. Oxygen in the carbonic acid gas given out by the lungs I 7 325 Oxygen in the carbonic acid gas given out by the skin ooin Oxygen in the organic matter given out by the kid- neys and intestine - - - - - -00 357 Oxygen in 'Jie water formed in the body - - - o 9 130 Total oxygen in waste - 2 2 47 Carbon in the carbonic acid gas given out by the lungs 08 320 Carbon in the carbonic acid gas given out by the skin - - - - - -- -00 40 Carbon in the organic matter given out by the kidneys - -00 170 Carbon in the organic matter given out by the in- testine - - - - - - - -00 308 Total carbon in waste ----- o 9 400 Hydrogen in the water formed in the body, and given out by the lungs and skin - - - o I 70 Hydrogen in the organic compounds given out by the kidneys and intestine - - - - -00 ICO Total hydrogen found in the water formed, and in the organic matter of the waste - o I 170 Nitrogen in urea and other waste given out by the kidneys - - - - - - -00 245 Nitrogen in waste given out by the intestine - - o o 46 Total nitrogen in waste - 00 291 Common salt given out by the skin - - - - o o 10 Common salt given out by the kidneys - - - o o 315 Total common salt in waste - - - - 00 325 Phosphates and potash salts given out by the kidneys (chiefly) o o 170 Water taken in as such, and given out by the lungs, skin, kidneys, and intestine, in addition to that formed in the body ------ 58 320 Total daily waste - - • - - 8 7 410 These figures, then, represent the daily balance-sheet of the income and expenditure of a human body—not exactly and per- fectly, but with a fair approach to truth. During the changes, mainly of oxidation, or burning, which are shown by the new RECAPITULATION. 55 compounds found in the waste and not in the supply, it is cal- culated that an amount of force is available, in one form or another of heat or mechanical work, which may be expressed as 3,950 tons raised 1 ft. high. Let us briefly restate the main facts concerning the food of man which we have been discussing in the preceding pages. 1. Food is required to increase or repair the materials of the body; to keep it warm, and to endow it with a renewal of working power. 2. The materials of the human body are arranged in many compound substances. These are made up of 16 elements; the same elements generally arranged in similar compounds being found in food. 3. Food substances, or nutrients, fall into two groups—the in- combustible or oxidized, and the combustible or oxidizable. Water and salts belong to the former; starch, sugar, fat, and com- pounds like the albumen of eggs, to the latter. 4. Incombustible nutrients serve several purposes, forming a permanent part of the body, and also acting as a means of carrying on the processes of nutrition. 5. Combustible nutrients are burnt more or less completely within the body by means of the oxygen taken into the lungs. The power of doing work, or potential energy, stored up in these nutrients and in the oxygen, is thus changed into the actual energy of heat and mechanical power. Thus the warmth of the body is maintained, and work done both internal and ex- ternal. 6. Combustible nutrients increase or replace the fat, muscle, &c., of the body. 7. The daily waste of the body must be met by a daily supply of nutrients in the daily ration of food. In an adult the supply and waste are equal in amount, but different in the nature of the compounds, though identical if the elements are con- sidered. 56 RECAPITULATION. 8. The daily ration must contain the various nutrients re- quired in due proportions of flesh-formers, heat-givers, saline matter, and water. The ratio may be expressed in numbers thus:— Wattr. Flesh-formes. "fstfrch"' Salt5- as iX 5,A °X PART II—OF VEGETABLE FOODS. Although repeated reference has been made already to different vegetable products, we have not given as yet any account of the chemical composition of particular kinds of plants, or of those parts of plants used for human food. But as the compounds which make up nearly the whole of every vegetable have been described, and their respective uses as nutrients discussed, the way has been cleared for the study of some of the most im- portant actual foods, such as wheat, peas, cabbage, and turnips. The review of these vegetable foods having been completed, foods of animal origin—milk, cheese, eggs, bacon, and butchers, meat—will also be described in Part III. from a chemical point of view. And then in Part IV. will be given some account of the composition and characteristics of alcoholic liquors, tea, to- bacco, and various condiments and spices—of the accompani- ments of food or "food-adjuncts," as we have named them. § i.—The Cereals. Naturally we give the first place to the breadstuff-s—wheat, oats, rice, and other grains—the fruit of certain plants belonging to the Grass Order, or Graminacea.* * Cases 24 to 36 inclusive. A collection of many of the varieties of wheat, oats, and barley cultivated in Great Britain, and various foreign countries—in the straw and ear, and also in grain.—A collection of samples of wheat, barley, maize, oats, &c, from the Argentine Republic, South America.—Samples of wheat, barley, oats, rye, and maize, grown in localities bordering on the line of the North Pacific Railway, United States. 58 VARIETIES OF WHEAT. Wheat. French, Ble. German, Weizen. Italian, Frumento. (Triticum vulgarv.) Wheat is an annual grass, of unknown origin. Numerous varieties of it are now in cultivation in nearly all temperate countries. It flourishes between the parallels of 25 and 60 degrees of latitude. It is more extensively grown in the northern than in the southern hemisphere. There are more than 150 named varieties of wheat, but in many cases the distinctions between them are very slight. The most important differences are those which refer to the composition of the grain ; but it will be found that these do not always agree with the outward characters of the grain or the ear. Wheats are generally characterised by some such terms as the following: Red or white, in reference to the colour of the grain; bearded or beardless, that is with or without an awn; winter or summer, the former being sown in autumn, the latter in spring; soft or hard, the soft wheats being tender and floury, the hard being tough, firm, and horn-like in appearance. This last distinction is the most important, as it corresponds to a real difference of chemical constituents and of feeding value. We shall recur to this point presently. Cases 24 to 20.* The average yield of an acre of land should be about 30 bushels of wheat grain, the bushel weighing 60 lb. In wet seasons the weight of a bushel of wheat grain may be as low as 55 lb.; while in good years it may rise to 64 lb. A plump, rounded, white, smooth grain, without wrinkles, gives the heaviest weight per * Various samples of wheat grown in South Australia in 1872.—Frame con- taining 104 varieties of wheat cultivated in Great Britain and elsewhere.— Samples of the various products obtained from wheat, and the quantities of flour, pollard, and bran obtained from half a peck of wheat. Wheat is subject to the attacks of several forms of fungi, as seen in the diagrams. They are known to the farmer by the name of rust, mildew, smut, and bunt. •COMPOSITION OF WHEAT. 59 bushel. Wheat grain varies in specific gravity between 1-29 and 1'41, the harder wheats being the denser. The proportion of grain to straw is greatest in dry years—perhaps the average may be stated as 4 to 10. The composition of wheat grain shows some variations, but they are limited to the relative proportions of starch and nitro- genous matters. Soft, white, and tender varieties of wheat, con- sisting entirely of opaque grains, may not contain more than 8 or 9 per cent. albuminoids; while hard and translucent sorts, such as those grown for the manufacture of macaroni, have been found to contain from 18 to 20 per cent. The starch in these latter grains is proportionately reduced. But differences in the com- position of wheat grain show themselves with the same variety of wheat, when it has been grown under different conditions, in fine, dry seasons the starch being increased and the albuminoids diminished, and the reverse being the case in wet summers. Even in the grains from a single ear, the same differences may be often seen—analysis showing sometimes 4 per cent. more albu- minoids in some of such grains than in others. It is difficult to fix upon a set of figures which shall fairly represent the average composition of wheat grain. But the following analysis may be taken as showing the proportions of the main constituents in a good sample of white English wheat:— Composition of Wheat. Case 37. In 100 parts. Water 14-5 Albuminoids, chiefly fibrin 11 -0 Starch, with trace of dextrin - - - - - 69 'o Fat 1-2 Cellulose and lignose ------ 2 "6 Mineral matter, or ash ------ 1"] According to this analysis, wheat contains 1 part of flesh- formers to 6j4 parts of heat-givers, reckoned as starch. And if In lib. OZ. %*■ 2 140 I 332 II 17 O 84 O 182 0 119 ■ 60 WHEAT. we assume that all the albuminoid matter present could be so used, not more than i^oz. of the dry nitrogenous substance of muscle or flesh could be produced from i lb. of wheat grain, such as is represented by the above analysis. The long, hard, trans- Cases 40 and 41.* lucent wheats grown in some of the hotter parts of Europe, might furnish twice as much flesh-forming material from an equal weight of grain. Macaroni, vermicelli, pates d'ltalie, and similar preparations are made from highly nitrogenous wheats. Some notion of the importance of wheat as a food-stuff may be gathered from the following figures. In 1875 there were about 3,350,000 acres under wheat in Great Britain. But the produce of all this land did not suffice for the needs of the people, and the produce of about 4,500,000 acres in foreign countries had to be brought to the United Kingdom—the United States and Russia contributing most of this foreign supply. Alto- gether, something like 5,000,000 tons of wheat are annually con- sumed in Great Britain. Then, too, it should be remembered that large quantities of wheaten flour and other preparations of wheat reach this country from abroad. There are several reasons why wheat is preferred to other cereal grasses for use as food. The grain is easily separated from the palea or chaff, which do not adhere to it as in the case of barley, oats, rice, &c. Then the yield of fine white flour, when wheat is ground in the mill, is very large. Wheaten flour, too, is readily made into a light and spongy bread. The chemical constituents of the wheat grain are likewise so proportioned as to render this food well fitted for the general sustenance of man, both as regards its flesh-forming and heat and force-producing character. Mill-Products. But wheat grain is nearly always prepared by some mechanical * Samples of macaroni, vermicelli, and other Italian pastes, made from the flour of hard wheat, grown in Algeria.—Macaroni, vermicelli, semolina, &c, prepared from wheaten flour, from Portugal, Italy, France, &c. MILL-PRODUCTS FROM WHEAT. 61 process or other before it is eaten as human food. Frumity, however, once popular in England, and still occasionally seen in Yorkshire, was made from whole wheat grains soaked in water and then boiled in milk. By grinding wheat between millstones meal is produced; and this, by sifting, winnowing, and re-grinding, is separated into a number of mill-products differing, not only in the size of the particles of which they are made up, but also in their chemical composition. To understand this we must examine the structure of the wheat grain, which is in reality a fruit, consisting of a seed and its coverings. All the middle part of the grain is occupied by large thin cells full of a powdery sub- stance, which is nearly white and opaque in soft wheats. This part contains much starch—indeed, nearly all the starch of the grain. Outside the central starchy mass is a single row of squarish cells, filled with a yellowish material very rich in nitrogenous— that is, flesh-forming—matter. Beyond this again there are six thin coverings or coats containing much mineral matter. This mineral matter contains both potash and phosphates. It should be added that the outermost coat of the above-named six coats is the least valuable, and in some processes of milling is removed by a previous operation. In Child's "Decorticator," for example, this thin bran, together with the germ of the grain, is first of all removed. In the process of Mege Mouries, also, this thin and poor outer coat is removed, but by a different plan—the grain being first damped and then rubbed. What then will be the effect of grinding upon grain having the structure just described? Grinding may be described as a process in which squeezes and blows are united. In pressing or squeezing wheat you may powder the interior, and yet not break up the exterior part; by blows you may divide the grain into a number of small fragments —a coarse meal, in which the white central portion of the grain is not reduced to powder. Now there are several modes of milling or grinding wheat, differing mainly in the preponderance of one or other of these two actions of squeezing and cracking. By 62 FLOUR AND BRAN. alterations in the distance between the stones, and by differences in the modes of scoring them, as well as in their direction and rate of motion, mill-products of different qualities are obtainable. The methods of "high-milling" have, indeed, become so com- plicated that it would be impossible to describe here the scores of operations, including many re-grindings and siftings, to which the grain is submitted. But we may at least say that, though a very fine white flour is certainly produced by this system, it is far smaller in quantity and less nutritious than fine white flour ob- tained by the ordinary English system. However, one advantage is said to belong to the more elaborate system, and that is that the various mill-products are not injured by over-heating during the treatment to which they are subjected. In the ordinary process of milling the wheat meal is produced in one grinding, and is then separated into three or more different products. In some flour mills the separation of the various qualities is far more thoroughly carried out than in others. The following is a classified list of the chief products of a flour mill, with the average quantities of each product obtained from ioo lb. of good wrhite wheat:— lb. f i. Finest flour 42 1 2. Seconds flour -------- 18 Flour J 3 Biscuit fiour g I 4. Tails, or tailings 3 : 5. Middlings, or fine sharps 8 6. Coarse sharps - 3 J (ran << 7- Fine pollard 3 8. Coarse pollard ------- - 6 9. Long bran -.-------3 It must be recollected that the above quantities are merely given as rough approximations, while the names applied vary in different parts of the country and in different mills. The first three qualities, or wires, for instance, are often sold together as "fine flour," while the quantity of this product is further raised (to 80 per cent. of the wheat taken) by re-dressing the tailings and re-grinding the middlings—which latter may be said to form FINE FLOUR. 63 a kind of link between flour and bran. There are some mills where only three different degrees of fineness are recognised— flour, middlings, and bran. As the chemical differences between the various mill-products are not all of equal value, we may select a few facts regarding their components from the number which have been accumulated. The cellulose and lignose, as well as the mineral matter and fibrin, are least in the fine flour. The fibrin is greatest in the pollard, and the mineral matter in the long bran. It will thus be evident that fine flour is inferior to pollard in bone-forming and flesh- forming nutrients. The following table makes this clear, showing how rich in these nutrients all those mill-products are which consist chiefly of the coverings of the seed. The toughness of these coverings is, of course, the reason why they are not reduced to a fine powder during the processes of milling. Case 37. One pound of Fine flour contains Tails „ Middlings ,, Coarse sharps ,, Fine pollard ,, Coarse pollard „ Long bran ,, Thin bran ,, Fibrin, z. gr. 297 389 105 246 2IO 196 182 290 Mineral Matter, gr. 5° 76 147 294 399 17 60 182 The thin bran named in this table is not obtained in ordinary flour mills; it forms the outermost coating of the grain, and may be removed by damping and then peeling the grain. It may be useful to give a more complete analysis of fine flour as obtained from white soft wheat:— Case 37. Water Fibrin, &c. ----- Starch, &c. Fat Cellulose - Mineral matter .... In 100 parts. In 1 lb. oz. gr. 13-0 2 35 io-s I 297 74-3 .. II 388 08 O 57 07 O 49 07 O 49 64 BRAN. One pound of gooa wheaten flour, when digested and oxidized in the body, might liberate force equal to 2,283 tons raised 1 ft. high. The greatest amount of external work which it could enable a man to perform is 477 tons raised 1 ft. high. For one part of flesh-formers in fine wheaten flour there are 7j£ parts of heat-givers, reckoned as starch. One pound of wheaten flour cannot produce more than about ifl oz. of the dry nitrogenous substance of muscle or flesh. Instead of giving analyses of all the other mill-products before named, we will cite one additional analysis only, that of a rather coarse bran :— Case 37. In 100 parts. In i lb. oz. gr. Water ------- 14 ... 2 105 Fibrin, &c. ...... 15 ... 2 175 Starch, &c. 44 ... 7 17 Fat -------- 4 ... o 280 Lignose and cellulose 17 ... 2 316 Mineral matter - - - - - 6 ... o 422 In comparing these numbers with those before given as repre- senting the composition of fine flour, it will be seen that bran not only contains more fibrin and mineral matter than fine flour, but also more fat. The fibrous matter, which is indigestible, forms Yd of the bran, but not T£u of the fine flour. For 1 part of flesh-formers in bran there are not quite 4 parts of heat-givers, reckoned as starch. One pound of wheaten bran contains flesh-formers equal to rather more than 2^ oz. of the dry nitrogenous substance of muscle or flesh. In bran there is a remarkable substance called cerealin, which acts like a ferment in causing the change and solution of other substances, and it may therefore aid in the processes of digestion when brown or whole-meal bread is eaten. There are many preparations of wheat which we can do little more than mention. Such are semolina and semola, which are WHEATEN BREAD. 65 made in grinding wheat (and other grains also, as those of the oat). They consist of small fragments of the interior of the grain, and are usually prepared from hard wheat rich in flesh- formers. It is from the same kinds of wheat that the macaroni, vermicelli, and the infinite variety of Italian pastes are prepared. Wheat groats, or grits, are distinguished from semola by the presence of the husk of the grain in large or small proportion. Bread. French, Pain. German, Brod. Italian, Pane. Of all the cereals wheat yields the best bread. This is due mainly to the peculiar character of the nitrogenous matter of wheat. This nitrogenous matter, of which the main constituent is a kind of fibrin, may be obtained in a separate form by making a little flour into a thick dough with water, and then washing the starch out of the mass by means of a stream of water. A grayish- yellow, tough, and elastic mass is left, which can be drawn out into threads. This substance is often called gluten; it is a mixture, but its chief ingredient is the albuminoid, or flesh-forming matter, fibrin. It confers upon a prepared mixture of flour and water, or dough, the property of yielding a sponge, which becomes firm, or sets, at the heat of the baking-oven. The bubbles which make the dough light are produced in different ways, but they are always filled at first with carbonic acid gas. The bubbles be- come larger as the dough begins to get hot in the oven, and finally they are fixed in shape and size by a higher degree of heat. There are three ways of turning dough into bread. In the first of these the carbonic acid gas necessary to produce the spongy texture is made within the dough by means of leaven, or yeast. Leaven is not much used in this country—its action is similar to that of yeast. Leaven consists of flour and water— sometimes mixed with salt and boiled potatoes—it is kept till it F DIFFERENT KINDS OF BREAD. 69 quantities of the several materials required to make a 2-lb. loaf, by the different processes just described:— I.—Ordinary or Fermented Bread. lb. oz. Flour 18^ Water, about 010 Yeast o 0% Potatoes o \% Salt o 0J6 It may be noted that more water than the above is often employed: that the small quantity of boiled potatoes here named, though generally thought to improve the bread, is not necessary; and that % oz. of salt is not an unusual proportion in the 2-lb. loaf. II.—Aerated or Dr. Dauglish's Bread. lb. oz. Flour l iyi Carbonated water 010 Salt - - - o 0% III.—Unfermented Bread. lb. oz. gr. Flour 180 Water 0100 Bicarbonate of soda 00 220 Hydrochloric acid 00 246 IV.—Whole-Meal Bread. lb. oz. Whole wheaten meal 19 Water ........ o 10 Yeast o 0% Salt o oyi There are several substances found in bread, or, rather, in the bread of some bakeries, which have no business there. They are chiefly introduced to whiten the loaf, to enable damaged or inferior flour to be used, or to cause the bread to retain more water than usual. Alum and sulphate of copper (blue vitriol) are employed for the former purposes, boiled rice and potatoes for the latter. The two chemical substances, alum and sulphate of 70 ADULTERATION OF BREAD. copper, are dangerous adulterants when added to a material in daily use like bread. A little pure lime-water answers the same purposes, and there is no reason to think it can be productive of the least harm. The case of boiled rice and potatoes is less serious. These materials are, of course, perfectly wholesome in themselves, indeed the latter material is often advantageously employed in making bread at home, on the small scale; but when these substances are used in order that i00 loaves may be got from a quantity of flour which should yield no more than 95, and when we know that this difference is caused by the larger quantity of water in the bread prepared with the addition of potatoes or rice, then these additions are justly described as adulterations. From what we have just said, it must not be assumed that the adulterants found in bread are the additions, in all cases, of the baker. Millers are known to employ several substances for the purpose of whitening, or otherwise improving the flour, or for fraudulently increasing its weight. Rice meal, bean meal, corn- flour, or Rivett wheat flour, and the flour of Dari (a sort of millet), have been frequently detected in the products of the flour mill. But these materials, though cheaper than wheaten flour, cannot be said to be such serious adulterations as those of a mineral character. Chalk, dolomitic limestone, powdered gypsum, china clay, and even heavy spar or barytes have been employed for this purpose. All of these mineral matters are useless, having no value as food; some are even injurious. Fortunately they can all be easily detected by chemical tests, while the adulterants named before (rice, &c.), require very careful examination in a good microscope. The mere fact that a sample of wheaten flour left, on being burnt, more than its proper proportion of ash would point to adulteration with some of the earthy matters which have just been named. Case 38. In times of scarcity, all sorts of vegetable matters have been mixed with wheaten flour and meal in order to eke out a limited supply of these nutritious matters. During the siege of BISCUITS. It Paris a coarse bread was made containing but little wheat, the main ingredients being potatoes and beans, with oats, rice, and rye, together with a good deal of fibrous vegetable matter in the shape of chaff and straw. In Norway and Sweden the sawdust of non-resinous woods, like beech and birch, is boiled in water, baked, and then mixed with flour to form the material for bread. And in England, during the seventeenth century, a very tolerable bread was made from a mixture of the pulp of boiled turnips with wheaten flour. Biscuits. Case 39. Biscuits are usually distinguished from bread by two differences: they are not vesiculated, and they are baked until they contain scarcely any water, sometimes not even 5 per cent. There are, of course, some exceptions to this rule, especially in the case of fancy biscuits. The word "biscuit" means twice cooked or baked, and is thus not applicable to the generality of biscuits now made. There are, however, some biscuits which have really been twice in the oven; such are rusks, which are made from flour, milk, butter, and sugar, first lightly baked as a kind of bread, then cut into slices and again put into a sharp oven, so as to scorch both sides. Afterwards they are thoroughly dried by a lower degree of heat continued for some hours. Most kinds of biscuits consist of a basis of flour and water, with slight additions of butter, sugar, and flavouring sub- stances. Unleavened, or Passover cakes, consist of flour and water alone. Diet, digestive, and bran biscuits contain or consist of bran. Abernethy biscuits contain caraway seeds. Cracknels are glazed with white of egg. Macaroons and ratafias are flavoured with sweet and bitter almonds. Ginger, lemon, and orange-peel, and many other flavourers and spices, are used as ingredients in fancy biscuits and cakes. All plain biscuits may be considered as more nutritious than bread, in the proportion of 5 to 3. They In lib. oz. gr- O 35° 2 252 10 352 I 269 o 259 o 147 OATMEAL. 73 lignose. * A careful analysis of a fresh sample of Scotch oatmeal showed the following results :— Composition of Oatmeal. Case 49. In 100 parts. Water - - - - • • • S-0 Fibrin, &c. 16-1 Starch, &c 63-0 Fat io-1 Cellulose and lignose - - - - 37 Mineral matter - - - • - 2'1 According to Frankland, 1 lb. of oatmeal, when digested and oxidized in the body, might liberate force equal to 2,439 tons raised 1 ft. high. The greatest amount of external work which it could enable a man to perform is 488 tons raised 1 ft high. It is, however, probable that the sample which was used in this experimental trial was decidedly inferior to fine Scotch oatmeal, the composition of which is given above. For one part of flesh-formers in Scotch oatmeal, there are 5^ parts of heat-givers, reckoned as starch, but the actual quan- tities of both flesh-formers and heat-givers are unusually large. One pound of oatmeal cannot produce more than about zyi oz. of the dry nitrogenous substance of muscle or flesh. One hundred pounds of oats (weighing 45^ lb. the bushel) commonly yield the following proportion of oatmeal, &c.:— From 100 lb. of oats. Oatmeal - • - - - 60 lb. Husks • - • - - - 26 „ Water 12 „ Loss 2 „ * Samples of oats in the straw, and of different varieties of the grain, may be seen in Cases 30, 31, and 32. 74 COMPOSITION OF BARLEY. Barley. French, Orge. German, Gerste. Italian, Orzo. (Hordeum vulgare.) Case42.» Barley belongs to the natural order of the grasses. The plant was originally a native of western temperate Asia. It is hardier than wheat or oats, and may be grown in high northern latitudes. It is not extensively cultivated in America; in Great Britain, 2,509,701 acres were devoted to this crop in the year 1875. Barley was largely used in ancient times as human food. Most of that grown in England is now converted into malt for making beer. Some is ground into meal and used for feeding pigs; while much is milled, yielding pot or Scotch barley and pearl barley. The whole grain is subjected to a rasping or paring process, by which the fibrous coats of the grain are more or less completely removed. Pot barley is the coarsest product, and retains some- thing of the original shape of the grain. Of this product about 63 lb. are obtained from 100 lb. of barley, but only half this amount of the finest pearl. Patent barley is pearl barley ground into flour. Pot and pearl barley are used in soups, puddings, &c. It will be seen from the annexed analysis that pearl barley is inferior to wheaten flour in flesh-formers. Composition of Common Pearl Barley. In 100 parts. Water I4-6 Fibrin, &c 6*2 . Starch, &c 76-0 Fat - I*3 Cellulose 0-8 . Mineral matter - • - - - I *I For 1 part of flesh-formers in pearl barley there are no less than i2^£ parts of heat-givers, reckoned as starch. * In Cases 33 and 34 samples of barley are shown. In lib. oz. gr- 2 147 O 434 12 70 O 91 3 56 O 77 COMPOSITION OF RYE. 75 One pound of pearl barley cannot produce more than 1 oz. of the dry nitrogenous substance of muscle or flesh. Barley flour does not yield a light bread, but it may be used for bread-making when mixed with wheaten flour. Rye. French, Scigle. German, Roggen. Italian, Segale. (Secale cereale.) Case 42. Rye, like wheat, oats, and barley, belongs to the grasses. It was formerly extensively grown in Great Britain, and is still cultivated to some extent, especially in the eastern counties of England ; but in most parts of this country rye is used as green fodder only. The grain of rye is employed mainly for malting purposes, but its flour may be- made into bread. Rye bread is dark-coloured, heavy, and sourish, but it keeps moist for a long time. It is a favourite food in many parts of Northern Europe, and is known as black bread. A palatable bread may be made from a mixture of 2 parts of wheaten flour and 1 part of rye flour. Rye grain is peculiarly liable to the attacks of a fungus, which produces the ergot of rye. The whole substance of the grain is altered and blackened, while a remarkable compound called ergotine is produced. This substance renders ergoted grain unwholesome, and sometimes even dangerous. The following table shows the Composition of Rye Flour. In 100 paits. Water ...... 13-0 Fibrin, &c. ...... to'5 Starch, &c ...... 71-0. Fat 16 . Cellulose 2-3 . Mineral matter ..... 1 '6 . In lib. oz. gr. 2 35 I 298 II 157 O 66 O 161 O 112 76 RICE. For i part of flesh-formers in rye flour there are 6% parts of heat-givers, reckoned as starch. One pound of rye flour cannot produce more than i ys oz. of the dry nitrogenous substance of muscle or flesh. Rice. French, Riz. German, Reis. Italian, Riso. (Oryza sativa.) Cases 43 and 44" Rice is a grass, a native of India. It is extensively grown in India, China, and the East generally; also in Carolina and Central America. It is likewise cultivated with success in the southern parts of Europe. Rice requires a high temperature and abundance of water to bring it to perfection; indeed the fields in which the crop is grown are irrigated. Many varieties of rice are cultivated, but they do not differ materially, as far as the com- position of the grain is concerned. Rice is more largely grown and consumed as human food than any other cereal. It is said to be the main food of one-third of the human race. Alone, however, it is not a perfect food, being deficient in flesh-formers and mineral matters. Rice is imported into this country from Carolina, Patna, Bengal, Arracan. When enclosed in the husk rice is known as faddy. By careful milling this husk is removed, and the pearled grain thus cleaned is what is generally known as rice. The rice husk, or shude, is harsh and fibrous in texture, and contains much lignose and silica. It is largely used in adulterating many articles of human and cattle food. Rice is used both in the form of the cleaned rice of the shops and ground into flour. Much starch is extracted from rice. Rice starch is readily changed into a kind of sugar, accompanied by some dextrin, when it is warmed with very weak sulphuric acid 7S COMPOSITION OF MAIZE. Maize, or Indian Corn. French, Elk de Turquie. German, Mais. Italian, Granturco. (Zea Mays.) Case 43.» Maize belongs to the grasses. It is a native American plant, but was soon introduced into the Old World. It is now largely grown in Southern Europe, North Africa, and North America. It is the corn of the United States, where numerous preparations of the grain are in use. The whole ear is spoken of as a cob; the pearled grains are called samp. Broken or split maize is known as hominy, while grains which have been heated or roasted so as to burst them are designated by the term pop-corn. Ground maize forms, when boiled, a very common and favourite food in the United States, being called mush. In Italy it goes under the name of polenta, while the more finely prepared meal is termed polentina. Maize will grow and often ripen its cobs in England, but it cannot be relied on as a field crop. Several varieties, and possibly more than one species, of maize are in cultivation. These differ much in the size, shape, and colour of the grain, and in other particulars as well; but in their com- position there is not much variation-" Composition of Maize. In ioo parts. In i lb. oz. gr. Water 14/5 ... 2 140 Fibrin, &c. 9'o ... 1 193 Starch, &c. 64'5 ... 10 140 Fat 5-0 ... o 350 Cellulose and lignose ... - 5-0 ... o 350 Mineral matter 2'fl ... o 140 * Numerous varieties of maize, including the whole ear or cob, the separated grain, and many preparations therefrom, are shown in Case 35. The following is a list of the countries furnishing most of these specimens: British Guiana, Egypt, France, Greece, New South Wales, Peru, Portugal, Queensland, Russia, Senegal, Spain, United States, Venezuela. Some specimens of maize grown near London are also shown in this Case. BUCKWHEAT. 81 The grain of many other grasses is used as food. We may cite as an instance the Russian preparation known as manna kroup, consisting of groats from the grain of the common grass, Poa fluitans. Buckwheat. French, Sarrasin. German, Buchweizeri. Italian, Grano Saraceno. (Polygonum Fagopyrum!) Case 43. This plant, though not a grass, may be fitly con- sidered here. It is largely grown in temperate countries for its starchy seeds, which resemble the grain of the grasses in com- position. Buckwheat is probably a native of Western Asia or Russia: it belongs to the order Polygonacea, which includes the rhubarb and the dock. Buckwheat is an annual of quick growth and easy cultivation. It is sown in Britain for feeding game and poultry, and is also grown for green fodder. The seed of buckwheat is enclosed in a husk containing much indigestible fibre. When this husk, amounting to about 20 per cent., has been removed, the richness of the seed in nutritive matters is very considerable. The published analyses of buckwheat deprived of its husk being very discordant, new analyses have been made with the following results:— In ioo parts. In 1 lb. oz. gr. Water - . 13-4 ... 2 63 Fibrin - . ■ - I5-2 ... 2 189 Starch - . . - 63-6 ... 10 77 Fat . 3-4 - 0 238 Cellulose and lignose 2-I 0 147 Mineral matter - 2-3 . ... 0 161 For 1 part of flesh-formers in cleaned buckwheat there are about 4% parts of heat-givers, reckoned as starch. G 82 PEAS. One pound of cleaned buckwheat contains flesh-formers equal to rather more than 2l/i oz. of the dry nitrogenous substance of muscle or flesh. § 2.—Pulse—Peas, Beans, &c. There is a marked difference in chemical composition between the seeds of leguminous plants on the one hand, and the grain of the cereals on the other. This difference mainly consists in the far higher proportion of albuminoids, or flesh-formers, in the former. In consequence of this difference, the ratio of flesh- formers to heat-givers in the seeds now under consideration is about i to 2%, instead of i to 5, as in wheat, or 1 to 10, as in rice. This fact suggests the proper mode of using pulse, which should generally be eaten with other foods rich in starch, sugar, fat, oil, or non-nitrogenous nutrients. Beans and rice, beans and bacon, are examples of such mixtures. The albuminoid which predominates in pulse is called legumin or vegetable casein. It occurs in leguminous plants generally, both in their green parts and in their ripe seeds. It appears to be more soluble and more easily digested in the unripe fresh seeds than after they have become ripe and dry; but it is usually considered a less valuable flesh-former than albumen or fibrin. Its resem- blance to the animal casein of milk is so decided, that in some parts of China cheeses are made from the seeds of beans and peas. The resemblance between different species of pulse is so great that we need not describe in detail all the cultivated sorts,* but may select as examples the garden pea, the haricot bean, and the lentil. Peas. French, Pois. German, Erbsen. Italian, Piselli. (Pisum sativum.) Case 46. The cultivated garden pea is probably derived from a plant native of countries bordering the Black Sea. It has been long * In Cases 31, 32, and 34 are samples of different kinds of beans, peas, chick peas, vetches, and lentils, from many countries. PEAS. 83 grown in England, and, like the French bean, is eaten unripe and green, as a fresh vegetable, and ripe, in the form of dried peas, split peas, and pea meal. Split peas have had the tough envelope of the seed removed. Unripe or green peas contain a considerable quantity of sugar, while the albuminoid matter in them is more easily digested than that in the same seeds when quite ripe. Dry, ripe peas, even when ground, require long but slow boiling, to render them fit for use; they constitute a valuable food, however, when properly cooked, in the form of pease-pudding and pea-soup. In common with other leguminous plants, and indeed with all products, animal as well as vegetable, which are rich in casein, peas are liable to occasion flatulence and colic. Peas and many other legumes contain a bitter substance, which predominates in some varieties so greatly as to render them unpalatable. This substance may, however, be removed in some measure by soaking the seeds or coarse meal in water containing a little common washing soda for some time: the liquor is then poured away. Composition of Peas. In 100 parts. In 1 lb. gr- Water I4-3 Casein, &c. 22-4 Starch, &c. 5I-3 Fat 2-5 Cellulose and lignose - - - - 6-5 Mineral matter 3-o 2 126 3 255 8 91 0 175 1 17 o 210 For r part of flesh-formers in peas, there are only 2j4. parts of heat-givers, reckoned as starch. One pound of peas contains flesh- formers equal to 3 y 2 oz. of the dry nitrogenous matter of muscle or flesh. According to Frankland, 1 lb. of dry peas, when digested and oxidized in the body, might liberate force equal to 2,341 tons raided 1 ft. high. The greatest amount of external work which it could enable a man to perform, is 468 tons raised 1 ft. high. G 2 84 PEA-SOUP. One of the most economical and nutritious articles of diet is pea-soup. One gallon may be made from—peas, 16 oz.; meat, 16 oz.; pot barley, i oz.; onions, i j4 oz.; salt, i }4 oz. ; sugar, i j4 oz.; black pepper, 40 grains; and water, 4 quarts. The peas should be first steeped in 3 pints of the water (cold) for 12 hours; the meat should be gently simmered in 5 pints of the water for 3 hours. The peas should then be put in a bag and boiled with the meat for 1 hour. The contents of the bag should then be pressed into the liquor, the skins which remain in the bag being removed. The salt, pepper, onions, and barley should now be put in, and the whole boiled for 1 hour, water being added, from time to time, to make up the gallon. Water in which bones, fresh meat, or such vegetables as carrots and parsnips have been boiled, may be substituted for the whole or part of the fresh water used, and the resulting soup will be still more nutritious. But even the best soups cannot be regarded as complete substitutes for the more solid foods—bread, cheese, potatoes, and meat. One pint of this soup will contain something like the following quantities of— Case 47. oz. gr. Water ........17 o Casein, &c. ....... o 270 Starch, &c. 1 o Sugar 056 Fat o 257 Gelatin o 147 Mineral matter ...... o 103 The field pea is Pisum arvense, and is generally thought to be the origin of all our cultivated varieties, although these are now grouped under the generic name of P. sativum. But there is a very distinct kind of pea, known as the chick pea, which belongs to a different genus—it is the Cicer arietinum. Chick peas are eaten in Spain, and very extensively also in the East, being generally parched or lightly roasted.* * Chick peas from Moldavia, Turkey, Portugal, Spain, and India are shown in Case 31. BEANS. 85 Haricot and French Beans. French, Haricots. German, Wdlschen Bohnen. Italian, Fagiuoli. (Phaseolus vulgaris.) Case 46. The French bean, the kidney bean, and the numerous varieties of haricots, are all derived from a plant which was in- troduced from India. This vegetable was and is largely grown in Italy and France, where its pods are usually allowed to ripen and the seeds to dry. In this country the pods are gathered when green and unripe, and eaten as a fresh vegetable; this is the case, also, to some extent, on the Continent, where the green pods are preserved in several ways so as to be available throughout the year. The dried seeds of this plant, known as haricot beans, when carefully and thoroughly cooked, are worthy of more extended use in England; they are universally appreciated in France. They should be eaten with starchy foods, like rice, or with bacon. Composition of Haricot Beans. Water - • Casein, &c. - Starch, &c. - Fat Cellulose and lignose Mineral matter In 100 parts. In 1 lb. oz. gr. 2 105 14-0 23'0 52-3 3 297 8 161 2-3 0 161 •5'5 .. 0 38s 2-9 0 203 For 1 part of flesh-formers in haricot beans there are only 2 j£ parts of heat-givers, reckoned as starch. One pound of haricot beans might produce nearly 3 ^ oz. of the dry nitrogenous substance of muscle or flesh. The scarlet-runner (Phaseolus multiflorus) closely resembles the French bean, and is used green in the same way. It is believed to be a native of Mexico. The ripe beans are not wholesome. The broad or Windsor bean is, when young, an agreeable and wholesome food. It is the seed of a distinct plant derived from the field bean, or Faba vulgaris. 86 COMPOSITION OF LENTILS. Lentils. French, Lentilles. German, Linsen. Italian, Lenti. (Ervum lens.) Case 46. This leguminous plant is extensively grown for human food in the southern parts of Europe. Numerous varieties exist, but they do not differ much in composition and nutritive value. This plant was cultivated by the Hebrews and other ancient nations. It is thought that the red pottage of Esau was made from the well-known red variety of lentil. Besides a bitter substance there is a good deal of useless fibrous material in the covering of lentil seeds. When this covering is removed the meal which lentils yield is of great rich- ness. It generally contains more casein than either peas or beans, but rather less than lupines. The preparations so much advertised under the names of " Revalenta," "Ervalenta," &c., contain lentil-meal, generally mixed with some barley or other flour, and common salt. They are sold at many times the value of the meals of which they are composed. Composition of Lentils. In 100 parts. In 1 lb. oz. gr. Water ....... 14-5 Casein, &c - • - • - - 24 o Starch, &c. 49-0 Fat 2-6 Cellulose and lignose - - - - 6-9 2 140 3 367 7 4°3 0 182 1 45 Mineral matter ..... 3-0 ... o 210 For i part of flesh-formers in lentils there are about 2% parts of heat-givers, reckoned as starch. One pound of lentils contains flesh-formers equal to 3^ oz. of the dry nitrogenous substance of muscle or flesh.* * Many samples of lentils, from Algeria, Egypt, France, Portugal, Reunion, Spain, Tripoli, and Turkey, are shown in Case 34. ROOTS AND TUBERS. 87 Ground or Pea Nuts. (Arachis hypogaa.) Case 46. The pods of this most curious leguminous plant are ripened below the soil. The plant is probably of American origin, but is grown in many hot countries, and is widely cultivated along the West Coast of Africa. It flourishes in a rich soil, and may grow to 2 feet in height. The Arachis somewhat resembles a large kind of clover in appearance; it has small bright yellow pea-like flowers, borne on long stalks; these, after flowering, curl down and force the immature pod into the soil. The seeds of the ground nut when green and unripe are roasted, and have a very pleasant taste. When ripe they are extremely oily, and require an admixture of starchy matter. Composition of Ground Nuts (shelled). Water - Casein - Starch, &c. - Oil Cellulose and lignose Mineral matter 100 parts. In 1 lb. oz. gr. 7-5 I 97 24-5 3 403 117 I 382 50-0 ..80 4-5 O 315 1-8 O 126 Ground nuts, after the greater part of the oil has been ex- pressed, yield a cake much used in this country for feeding cattle. But in many tropical countries these nuts are consumed as human food. Many other leguminous seeds and pods are eaten besides those named above. Such are, the pigeon pea (Cajanus indicus), of India; a plant nearly allied to the ground nut (Voandzeia subterraned)-y and numerous Indian and Chinese species of Dolichos. § 3.—Roots and Tubers Cases 48,51, and 52. It will have been noticed that the vegetable products (corn and pulse) already considered contain but a 88 POTATOES. moderate portion of water, generally something like 14 per cent., or 2 oz. in the pound. But it will presently be seen that all fresh and moist vegetables, whether roots, leaves, or fruits, contain much more water. Potatoes, indeed, are richer in nutrients than many other moist vegetables, but even they contain 75 per cent. of water, or 12 oz. in the pound. White turnips, on the other hand, contain from 91 to 93 per cent., or nearly 15 oz. in the pound. Another point of difference between the drier foods already studied, and those to which attention is about to be directed, lies in the presence of more considerable proportions of albumen amongst the flesh-formers of moist roots and tubers. We give the first place to the potato. Potatoes. French, Pommes de terre. German, Kartoffeln. Italian, Pomi di terra. (Solanum tuberosum.) The potato belongs to the nightshade order, which includes a very large number of poisonous plants. The tubers, which are enlargements of the underground stem, form, next to the grain of the cereals, our most important vegetable food. The potato plant has been found wild in Chili, Peru, and Mexico. It was brought to Ireland by Sir John Hawkins, in 1565; to England by Sir Francis Drake in 1585, and in the following year by Sir W. Raleigh. Gerarde figured the plant in his "Herbal," published in 1597. But this vegetable did not become popular until towards the close of the eighteenth century. Many varieties of the cultivated potato exist, but variations in chemical composition shown by this tuber depend more upon its size and maturity than upon the variety. Since the year 1845 the potato has been the subject of a disease, known as the potato murrain, which causes the foliage to die off suddenly and the tubers to decay. The murrain prevails in damp warm sum- POTATOES. 89 mers, when there is a heavy rainfall in June or July, and when the rain falls on many days. Such conditions are favourable to the growth of the parasites, mildew, or fungus, which is the immediate cause of the disease. Good drainage, with plenty of air for the plants, and no excess of decaying matter in the soil, are amongst the best means of moderating the attacks of the fungus, which generally goes by the name of Peronospora infestans, but has been lately described as a Phytophthora. Slightly diseased potatoes may be utilised in many ways. If cut at once in thin slices or granulated, they may be dried in hot- air chambers, and will keep for years. They again absorb water when placed in it, and may be cooked in the usual manner. The starch, even in badly diseased potatoes, is but little affected, and may be obtained from the pulped tubers by washing them on a cloth in a stream of water. From potatoes many products are obtained. These are made from the starch of the tuber, which is a good and cheap substitute for arrowroot. This starch, by roasting, becomes dextrin, or British gum. By boiling with weak sulphuric acid, potato starch is changed into glucose or grape sugar, and this, by fermentation, yields alcohol. Large quantities of spirits are made from potato starch, and are sold under the name of British brandy. The peel or rind of potato tubers contains a poisonous sub- stance called solanine. This is destroyed or dissipated when the potatoes are boiled or steamed. Large quantities of potatoes are now imported into England from abroad. The potato being rather deficient in flesh-formers, cannot be used as a complete food, but is best employed as an addition to pulse, lean meat, or other nitrogenous foods.* * Numerous specimens of starch and starchy preparations made from the potato are shown in Cases 49 and 50. These include imitation sago, tapioca, macaroni, and vermicelli. Glucose, and dextrin from potato starch are also shown. The specimens are from Brazil, France, Holland, Prussia, and Sweden. In lib. oz. gr. 12 o O 161 2 2IO O I40 O 21 O 70 O 70 90 TURNIPS. Composition of Potatoes. Csse 49 In 100 parts. Water -"- 75-0 Fibrin and albumen - - - - 23 Starch - 15-4 Dextrin and pectose .... 2 'O . Fat ....... o'3 Cellulose .-..-- I'o. Mineral matter ..... 1 -0 . For i part cf flesh-formers in potatoes it would appear that there are 10 parts of heat-givers, reckoned as starch. But it is doubtful whether the flesh-formers are not much exaggerated in the above, as in all published analyses. Recent experiments tend to show that the ratio of flesh-formers to heat-givers is nearer 1 to 20 than 1 to 10. According to Frankland, 1 lb. of potatoes, when digested and oxidized in the body, might liberate force equal to 618 tons raised 1 ft. high. The greatest amount of external work which it would enable a man to perform is 124 tons raised ift. Turnips. French, Novels. German, Weissen Riiben. Italian, Navoni. (Brassica rapa.~) Case 48. The turnip belongs to the Order of the Cross-flowers, or Crucifera, so called because of their four petals being arranged as a cross. The Swedish turnip, which is rather more nutritious than the common turnip, is said to have sprung, not from Brassica rapa, but from another plant, B. campestris, which also gave rise to rape and colza. The turnip, like many other plants of the same order, contains a pungent essential oil. The root is very watery, and contains but little nourishment. Unlike the potato, the turnip contains no starch, but, instead, a jelly-like matter, belonging to what is called the pectose group. It appears, from recent experiments, that CARROTS. 9i turnips contain no more than one-half per cent, of flesh-formers, instead of the 1 per cent. usually assigned to them. Composition of White Turnips. In 100 parts. Water - Albumen - • Pectose Fat Cellulose and lignose Mineral matter 92-8 o-5 4-0 O-l 18 o-S In lib. OZ. gr- 14 371 O 35 O 210 O 7 O 126 O 56 For 1 part of flesh-formers in turnips there are 8 parts of heat-givers, reckoned as starch. Carrots. French, Carottes. German, Mohren. Italian, Carotte. (Daucus carota.-) Case 48. The wild carrot grows abundantly on our southern coasts. It belongs to the Umbellifer Order, which includes many edible plants, as celery, parsnip, and parsley; and many poisonous ones, as hemlock. The wild carrot, which is of pungent odour and disagreeable taste, has become much milder and more succulent by cultivation. The cultivated plant is said to have been intro- duced into England during the reign of Elizabeth. Carrots, unlike parsnips, contain no starch. They are more watery than parsnips of the same size, but they are more generally liked. The carrot is grown in all the quarters of the globe. Well-grown carrots (weighing about 8 oz.) contain— Water - Albumen Sugar - Gum and pectose - Fat Cellulose and lignose Mineral matter In 100 parts. In 1 lb. oz. gr. 89-0 14 10S o-5 0 35 4-5 0 315 0-5 „ 0 35 0*2 0 14 43 0 301 i-o 0 70 92 PARSNIPS. For i part of flesh-formers in carrots there are 10 of heat- givers, reckoned as starch. One pound of carrots cannot produce more than Yl2oz. of the dry nitrogenous substance of muscle or flesh. According to Frankland, i lb. of carrots, when digested and oxidized in the body, might set free a force equal to 322 tons raised 1 ft. high. The greatest amount of external work which it could enable a man to perform, is 64 tons raised 1 ft. high. Parsnips. French, Pandis. German, Pastinaken. Italian, Pastinache. (Pastinaca sativa.) Case 48. The garden parsnip is a cultivated variety of the wild parsnip, a native umbelliferous plant, like the carrot . The cultivated variety has been grown since Roman times. The parsnip contains less water than the carrot. There is a good deal of starch, with some sugar, present in this root. The parsnip is often eaten with salt fish and salt beef, but its peculiar taste and texture are disliked by many persons. Both spirits and beer are occasionally prepared from parsnips. The chief constituents of parsnips are shown in accordance with the following analysis :— Water - Albumen Sugar - Starch ... Pectose and dextrin Fat Cellulose and lignose Mineral matter In 100 parts. In 1 lb. oz. gr. 81-0 12 420 1-2 0 84 3-° O 210 3-5 0 245 2 *2 0 154 i*5 O I05 5-6 O 392 I-O O 70 For 1 part of flesh-formers in parsnips there are 10 parts of heat-givers, reckoned as starch. One pound of parsnips cannot produce quite *4 oz. of the dry nitrogenous substance of muscle or flesh. JERUSALEM ARTICHOKES. 93 Beet Root. French, Betteraves. German, rothen Ruben. Italian, Barbabietole. (Beta vulgaris.) Case si. The sea-beet (B. maritimd), common on our southern shores, is thought to be the origin of the garden-beet, the sugar- beet, and the field-beet or mangold-wurzel. The red garden-beet has been long grown in England. Its root, which is of a rich red colour, is boiled, and then sliced and eaten in salads or alone. The plant belongs to the Goose-foot Order (Clwiopodiacetz). The garden-beet contains nearly as much sugar as the best sugar-beet, which is so largely grown for making sugar in France, Belgium, Germany, &c.* The quantity of flesh-formers in beet-root is but one-third of the amount usually assigned to this food, the greater part of the nitrogen present existing as nitrates, &c. Roots of garden-beet contain- Water Albumen ... Sugar - Pectose ... Fat - Cellulose and lignose - Mineral matter - In 100 parts. In lib. 0*. gr. 82-2 13 67 0-4 O 2S io-0 I 262 3-4 0 238 o-1 0 7 3-0 0 210 0-9 0 63 For 1 part of flesh-formers in beet-root there are more than 30 parts of heat-givers, reckoned as starch. Jerusalem Artichokes. French, Topinambours. German, Erdapfel. Italian, Tartufoli. (Hettanthus tuberosus.) Case st. Jerusalem artichokes are the tubers of a kind of sunflower, which is thought to have been a native of Mexico * A series of products obtained in the manufacture of sugar from beet-root is shown in Case 10. SWEET POTATO. 95 Moderate-sized English onions contain on an average the lowing proportions of their chief constituents :— In ioo parts. In 1 lb. oz. gr. 14 245 91-o i-5 o 105 4-8 ... 0 336 0'2 0 14 2TJ 0 140 05 0 35 Water Albumen Mucilage and pectose Fat - Cellulose and lignose Mineral matter - For 1 part by weight of flesh-formers in fresh onions there are about 3/^ parts of heat-givers. One pound of onions cannot produce quite % oz. of the dry nitrogenous substance of muscle or flesh. Sweet Potato. Batatas edulis. Case s1. This plant belongs to the Convolvulus Order. It is probably a native of the warmer parts of the American continent, where it has long been extensively grown. It is also cultivated in Algeria and in Southern Europe. It has been called the Spanish potato. The chief difference between the tubers of this plant and those of the true potato lies in the presence of sugar in the former. The tubers of the sweet potato, and those of the different kinds of yam, resemble one another somewhat closely as to their constituents and feeding value, but they are the produce of plants belonging to widely different natural orders. The sweet potato contains- Water - Albumen Starch - Sugar Pectose and gum Cellulose Mineral matter n 100 parts. In 1 lb. 74-0 oz. gr. II 368 1-5 O 105 15-0 2 175 3-0 0 210 2-2 O 154 2-8 O I96 i"5 O 105 r 96 YAM. For i part of flesh-formers in the sweet potato there are 13 parts of heat-givers, reckoned as starch. One pound of sweet potatoes cannot produce quite }£ 02. of the dry nitrogenous substance of muscle or flesh. Yam. (Dioscorea alata.) Case 5». The tubers of several species of twining shrubs be- longing to the genus Dioscorea are known as yams. The yam is grown in most tropical and some sub-tropical countries. It flourishes in Japan, the East and West Indies, the South Sea Islands, and is an important article of food. The tubers some- times weigh 30 and even 40 lb. A kind of yam from China (D. batatas), called in French Igname de Chine, is cultivated with some success in France and Algeria; the produce has been known occasionally to exceed 23 tons of tubers per acre. There is much resemblance both as to chemical composition and taste between the yam and the common potato. Yams contain on an average— In 100 parts. Water 79-6 Albumen ..... 2*2 Starch - - - - - 16-3 Fat 0-5 Cellulose 0-9 Mineral matter - - - - I *5 For i part of flesh-formers in the yam there are lYz parts of heat-givers, reckoned as starch. One pound of yams cannot producemore than yi oz. of the dry nitrogenous substance of muscle or flesh. A few other roots of less importance, which are sometimes used as accompaniments of meat, may be named here. In 1 lb. oz. gr. 12 322 0 '54 2 196 O 35 0 63 0 105 CABBAGE. 97 The parsnip-chervil (Anthriscus bulbosus), a native of France, has an edible root like a small carrot. Rampion (Campanula rapunculus) is much grown in France, for the sake of the roots, which are boiled till tender. Skirret consists of the small tuberous roots of a large, coarse, umbelliferous plant (Stum Sisarum) from China. They are boiled for use. § 4.—Leaves, Stems, Stalks, and whole Plants. The cabbage, with the numerous plants botanically connected with it, does not differ widely in nutritive value from the turnip. But it should be recollected that important mineral matters, as potash salts and phosphates, together with vegetable acids, flavouring substances, and a variety of active principles, are present in notable quantities in many of the succulent vegetables which we are about to consider. The asparagine in asparagus, the nitrate of potash in lettuces, and the pungent essential oil in watercress are instances in point. It will, therefore, be con- venient to group these and many other plants together, not because they resemble one another much, but because they all form agreeable and wholesome accompaniments to more solid and nutritious articles of food. It should be added, that the great majority of the plants in this section are distinguished from those previously considered by the presence of chlorophyll, the green colouring matter of leaves; its nutritive value is not known, how- ever, as yet. Caebage. French, Chou. German, Kohl. Italian, Cavolo. (Brassica oleracea.) Case 52. The wild plant, one of the Crucifera, from which the cabbage sprung, grows upon the southern and western coasts of England, Wales, and Ireland. The same native plant is also 11 98 CABBAGE. the origin of Scotch kail, Brussels sprouts, savoys, red cabbage, and the cauliflower and broccoli. The popular German food, sauer-kraut, is made from sliced cabbage, sprinkled with salt, pressed and fermented. The inner and younger leaves of the cabbage contain much more water than the older leaves outside. On the whole, this vegetable may be considered more nutritious than the turnip. The chief constituents of cabbage are shown in accordance with the following analysis :— . In ioo parts. In 1 lb. Water - 89-0 oz. gr. 14 IO5 Albumen .... • - i-5 O IO5 Sugar, starch, and gum - - - 5-8 - 0 406 Fat - 0-5 0 35 Cellulose and lignose 2-0 0 140 Mineral matter ... I-2 0 84 For 1 part of flesh-formers in cabbages there are about 4^S parts of heat-givers, reckoned as starch; broccoli and cauli- flower are rather richer in flesh-formers than cabbage. One pound of cabbage contains flesh-formers equal to nearly % oz. of the dry nitrogenous substance of muscle or flesh. According to Frankland, 1 lb. of cabbage, when digested and oxidized in the body, might set free force equal to 261 tons raised 1 ft. high. The greatest amount of external work which it would enable a man to perform is 52 tons raised 1 ft. high. Besides the cabbage and its many varieties, the green leaves of several other plants are eaten after having been boiled. Spinach {Spinacia oleraced), a native of Western Asia, is used in this way} and is a wholesome vegetable; it contains much nitre. The leaves of some of the smaller varieties of beet (Beta vulgaris) are sometimes substituted for spinach. The mountain spinach, or orache (Atriplex hortensis), was once much grown in this country, and is still cultivated in France; it is a native of Tartary. The young shoots or tops of the common stinging nettle (Urtica dioicd) SEA-KALE. 99 are not unlike spinach when properly boiled and dressed. The leek (Allium Porrutn) is another green and succulent vegetable, which is esteemed especially by the Scotch and Welsh. The whole plant, bulb and leaves, is eaten. It should be blanched by earthing up. It may be simply boiled, or introduced in place of onions (which it resembles in flavour and composition) into soups and stews. The next plant in this section, and one which we may describe more fully, is sea-kale, which is rendered mild and agreeable in taste by being earthed up. Sea-kale. (Crambe maritima.-) Case 51. The sea-kale is a native perennial Crucifer. It is found, though rarely, in a wild state, upon some of our sandy and shingly coasts. It has been cultivated in England for more than 200 years, and was introduced to the Continent from this country. Cultivated sea-kale is larger and more succulent than the wild plant, and has a more agreeable taste. It is earthed up, and the blanched stems and leaf-stalks then produced are eaten, after having been boiled. Sea-kale usually contains no sugar, but a good deal of mucilage and some starch. Freshly-cut sea-kale contains— In 100 parts. Water 93-3 Albumen - - - - - - 2-4 Mucilage and starch - - - - 2 -8 Cellulose - - - - - - C9 Mineral matter - - - - - o-6 Sea-kale contains a good deal of nitrogenous matter of one kind or another, but it is probable that the proportion of flesh- formers to heat-givers is not exactly shown in our analysis, which, indeed, gives the ratio i to i, or thereabouts. In lib. oz. gr- ... 14 406 0 168 0 196 0 63 0 42 H 2 i00 VEGETABLE MARROW. The Cardoon is a perennial composite (Cynara Carduneulus), a native of Southern Europe. It is much like the common artichoke, but the part eaten is the blanched stalk of the young leaves. It is a very handsome plant. The Artichoke (Cynara Scolymus) is a native composite from Barbary and Southern Europe. The fleshy receptacle of the flower, the fleshy scales of the involucre, and the blanched leaf stalks are eaten after having been boiled. They have a delicate flavour and agreeable texture, but contain little nutritive matter. The young buds are sometimes pickled. Asparagus (Asparagus officinalis) is a wild seaside English plant, made more succulent by cultivation. It is remarkable as containing a crystalline alkaloid, asparagine, which is thought to possess diuretic properties. The next articles of vegetable food which we shall notice in the present section are the vegetable marrow and the tomato. In both these plants it is the fruit which is eaten, but as these fruits are not valued because of that usual ingredient of fruits—sugar— but are used to accompany meat and other foods with which salt is eaten, they may be suitably considered here. Vegetable Marrow. (Cucurbita ovifera.) Case S3. The vegetable marrow is thought to be a variety of the common gourd (Cucurbita maxima), a plant which appears to have given rise also to the pumpkin and the squash. The vegetable marrow is now largely grown in England. It delights in a rich and open soil, with abundance of moisture. Although the fruit of the vegetable marrow is very watery, yet it contains more nutritive matter than its close ally, the cucumber. In vegetable marrows, when fit for cooking, starch as well as sugar occurs. Peeled and properly cooked, young vegetable marrows form a wholesome and agreeable food, of delicate flavour and pleasant consistence. TOMATOES. 101 Peeled vegetable marrows contain— In ioo parts. Water - Albumen Sugar Starch - Fat Cellulose Mineral matter 94-8 o-6 2'0 o-6 0 2 o-5 In 1 lb. gr. '5 o o o o o o 73 42 140 42 H 91 35 For 1 part of flesh-formers in the vegetable marrow there are about 4 parts of heat-givers, reckoned as starch. Tomatoes. French, Pommes d'amour. German, Liebesapfd. Italian, Pomid'oro. (Lycopersicum esculentumj) Case 53. The tomato, or love apple, is a plant belonging to the Nightshade Order—an order which includes the potato, the capsicum, and tobacco. It is most probably a native of Mexico. The fruit of the tomato requires a good deal of heat to ripen it thoroughly. The plant should be trained on a sheltered wall. They require good soil, and abundance of water. The tomato is now much more grown in England than formerly, several varieties, some with yellow and others with red fruit, being cultivated. Ripe tomatoes, which have a pleasant acidulous taste, are used in sauce and in other ways with cooked meat. Unripe tomatoes make a good pickle. Ripe tomatoes contain— Water - Albumen Sugar ... Malic acid Cellulose and pectose Mineral matter For 1 part of flesh-formers in of heat-givers, reckoned as starch In 100 parts. In lib. 89-8 oz. gr. •• 14 161 1 "4 O 98 6-0 O 420 07 0 49 1 "3 O 9' o-8 O 56 omatoes there are about 4 parts f io2 MUSHROOMS. Fungi and Mushrooms. The value of cryptogamic plants generally as food is ill under- stood; and especially is the real nature of the several consti- tuents in the numerous kinds of fungi which have been eaten safely, still in some measure doubtful. A delicate and agreeable flavour is possessed by the common mushroom (Agaricus campes- tris), and by several allied species—by the morel (Morchella escu- lenta), and by the truffle, an underground species (Tuber cibarium); but none of these plants can be regarded as substantive articles of diet . They are used chiefly as flavourers in the form of sauces, like ketchup, or, as in the case of truffles, as stuffing for animal food. The truffle, it should be stated, is sought for by means of dogs trained to scent it; in France pigs are employed. Amongst other edible fungi (many of which are often called toadstools) may be named the champignon (Marasmius oreades), the chanterelle (Cantharellus cibarius), the orange agaric (Lac- tarius deliciosus), the edible boletus [Boletus edulis), and many other species. But it is hazardous for persons who are not well acquainted with fungi to attempt to distinguish between those which are harmless and those which are poisonous. Serious and even fatal mistakes have thus arisen. We give some details concerning the common mushroom, as an example of this kind of food.* Mushrooms. French, Champignons. German, Schwamme. Italian, Funghi. (Agaricus campestris.) Case s4. This is the fungus or mushroom generally eaten in England, although several other species are used as food on the Continent, and occasionally in this country also. * In Case 54 are shown two specimens of a fungus (Mylitta australis) called "native bread," from Tasmania; also dried edible fungi from Tahiti, preserved fungi, and various preparations of the common mushroom. Numerous drawings of British edible and poisonous fungi are exhibited near this Case. ICELAND MOSS. 103 The common mushroom, the champignon, and the morel, are nearly identical in chemical composition; the truffle contains more than twice as much solid matter. Mushrooms are highly nitrogenous; they also contain much fat. Mushrooms may be stewed, broiled, or pickled. When salted and pressed, they yield ketchup, an agreeable sauce. The chief constituents of mushrooms are—• Water Albuminoids, &c. Carbohydrates, &c. Fat - Mineral matter - In 100 parts. In 1 lb. oz. gr. 90-0 14 175 5-0 . O 350 3-8 O 266 07 O 49 0-5 0 35 Though mushrooms contain, when dry, about half their weight of nitrogenous matter, its nature and feeding value have not been ascertained. Lichens. Case 55. Although several kinds of lichen have been turned to account in the arts (as in dyeing), very few are used as food. Tripe de roche, or rock tripe, is one of these, however—or we should say that the several plants to which this name is given have been occasionally used as food by distressed Arctic voyagers. Lung lichen {Sticta pulmonarid), several kinds of Peltidea, and the reindeer moss (Cladonia rangiferind), are also edible. But the best known of all these cryptogamic plants is the lichen com- monly called Iceland moss. It may be taken as illustrating the composition of all the edible species. Iceland Moss. (Cetraria islandica.) Case 55. This plant is not a moss, but a lichen. It grows abundantly in high northern latitudes, upon otherwise barren rocks: it is also found in the mountainous districts of Great Britain, Ireland, and even of Southern Europe. SEA-WEEDS. ios rather to be regarded as occasional dainties, and as affording an agreeable substitute for ordinary vegetables. One kind described more fully further on, is made into a jelly for consumptive patients. Besides this we name, Laver or sloke (Porphyra laciniata and P. vulgaris) is found on the English coast. It is salted, and dressed with vinegar, pepper, and oil. Green laver (Ulva lactuca and U. latissima) resembles the purple laver, but is inferior. Tangle, or red ware, also called by other names, is Laminaria digitata and L. saccharina. It requires thorough boiling, and is then to be eaten with butter, pepper, and lemon-juice. Badderlochs, hen ware, honey ware, murlins (Alaria esculentd). The part of the plant which is eaten is the thick midrib which runs through the frond and the fruit-bearing appendages. The dulse of the south-west of England is the Iridaa edulis of botanists. It is said to resemble in its flavour roasted oysters. Dulse of the Scotch, dellisk, dellish, duileisg, water-leaf (Rhodymenia palmatd). The Icelanders use it as an article of diet, under the name of the sugar fucus. It is also used to flavour soups, ragouts, and other dishes. Several other sea-weeds are employed as food. Ceylon moss is Plocaria Candida. In China the people are very fond of them, and many kinds are collected and added to soups, or are eaten alone with sauce. One of these, a species of Nostoc, the Plocaria tenax, is called Chinese moss. The Corsican moss should be Gracilaria Helminthocorton, but is generally Laurencia obtusa. It is found on the coasts of the Mediterranean. Another sea-weed was recently imported into London under the name of Australian moss (Eucheuma speciosum), but it tastes too strongly of the sea to be pleasant. Durvillaa utilis is another sea-weed, used at Val- paraiso as food. Spharococcus lichenoides is found on the south coast of England, and has been used in pickles and soups. The commonest edible seaweed is called 106 SALAD PLANTS. Irish Moss. (Chondrus crispus.") Case 5s. Irish moss (really a sea-weed) is one of the few marine plants which is commonly used as human food in Europe. It is abundant on our rocky coasts. Irish moss is collected on the north and north-west shores of Ireland; some is imported from Hamburg. The true Irish moss, or carraigeen, is Chondrus crispus, but other species, such as Gigartina mamillosa, are frequently col- lected with it. Both these kinds, as well as several similar edible sea-weeds, have about the same nutritive value, which is con- siderable. The chief constituent of Irish moss is a kind of mucilage, which dissolves to a stiff paste in boiling water. There is also a little iodine and much sulphur in it. Before boiling it in water or milk, Irish moss should be soaked in cold water for an hour or so. Irish moss is used as a food, and as a remedy in chest diseases. It is sometimes given to farm animals. Irish moss, as sold, contains— In 100 parts. In i lb. oz. gr. Water i8-8 ... 3 3 Albuminoids ..... 9-4 ... 1 221 Mucilage, &c. ----- 55'4 ... 8 378 Cellulose ..... 2'2 ... o 154 Mineral matter .... 14-2 ... 2 119 For 1 part of flesh-formers in Irish moss there are about 5^ parts of heat-givers, reckoned as starch. Salads. Salad plants are very numerous; but in former times many green vegetables were eaten uncooked which are now entirely forgotten. In 1669, Evelyn gave a list of 73 plants so used. His SALAD PLANTS. 107 "Discourse of Sallets" includes a large number of weeds, the present neglect of which is not to be regretted; yet some few of the green, fresh herbs which he names, might be introduced again with advantage. In France, the variety of salads in common use is much greater than in England, and it must be added, that the skill in preparing them for consumption is more marked. Too much care cannot be bestowed in the thorough cleansing of salad herbs, especially in the case of watercresses, with which many internal parasitic or entozoal animals are often introduced into the human body. Salad plants generally contain but little nourishing food of the heat-giving and flesh-forming kinds. But they are useful as being comparatively rich in saline matters, especially in potash salts, which are generally extracted from cooked vegetables in the process of boiling. They serve also to introduce large quantities of water into the system, and are refreshing additions to richer foods, especially in hot weather, when their "crisp, cool succulence" is peculiarly acceptable. In order to be thus juicy and crisp, lettuces and other salads, such as cucumbers, must not be gathered when wilted and drooping after a hot day; too often this is the case, or else subsequent partial drying causes toughness. To obviate this defect, the root of lettuce or celery, &c., when dug up, should be trimmed under water, so as not to expose the cut stem or leaf-stalks to the air. The plants will then, if left in the water, imbibe more fluid very readily till their tissues are well filled. The stalk of the cucumber should be cut under water, and remain in it just in the same way. In addition to lettuce, celery, watercress, and cucumber, which are more fully described further on, the following salad plants may be here noted: Cress (Lepidium sativum) is a small cruciferous annual, probably a native of Persia. Its seeds may be grown very readily upon any moist surface, and are commonly sown with those of white mustard, to yield the familiar spring salad known as mustard and cress. The Radish (Raphanus sativus), like most cruciferous plants, io8 CELERY. has a pungent taste. When small and quickly grown, it is adapted for use in salads. It may be cooked with advantage. Endive (Cichorium Endivid) belongs to the Composite: it is a native of Northern China. It is much used in salads, but its leaves, even when blanched, are rather bitter. Succory or Chicory (Cichorium Intybus) is a wild English plant, near the endive. Its leaves, when blanched, are used as salad. Borage, is Borago officinalis; it is used in claret and cider cups chiefly. Its leaves have a taste resembling that of cucumber. Burnet (Poterium sanguisorba) belongs to the Rosacea; its leaves, like those of borage, have much the taste of borage, and are used similarly. Samphire (Crithmum maritimum) is an aromatic and saline umbelliferous plant, common on many sea shores and cliffs. Once it was much used in salads; now its leaves, gathered in May, are employed only in pickles. Sorrel (Rumex scutatus), a hardy perennial, native of Southern Europe, is much grown in France as a salad herb. The English species (R. acetosa and R. acetoselld) are less juicy and more sour. All the kinds of sorrel contain oxalic acid and oxalates in abundance. Beet-root has been already described (p. 93). A fair idea of the composition of the fresh and juicy vegetables commonly used as salads may be gathered from the following analysis. It is necessary to state, however, that the flavour of these plants, depending, as it generally does, upon traces of volatile oils too small to be weighed, is not explained by the figures representing the chief components of these vegetables. Celery. French, Cileri. German, Sellerie. Italian, Sedano. (Apium graveolens.) Case 56. Celery is a native biennial umbellifer, common in LETTUCE. 109 sandy marshes. The wild plant has a very strong and disagree- able taste and smell; the cultivated varieties are tender, mild, and succulent, when earthed up and supplied with abundance of water. The blanched leaf-stalks of celery are eaten uncooked, as a salad herb, and are also introduced into soups; they may also be stewed in the same manner as onions or sea-kale. The fruits of celery contain more than the other parts of the plant of the peculiar essential oil to which its characteristic odour and flavour are due. The quantity of this oil in celery as eaten is too minute to be represented in the analysis. Celery, it will be seen, contains some sugar. Freshly-cut celery has the following composition :— In 100 parts. In 1 lb. Of. gr. 93-3 14 406 I *2 O 84 i-6 O 112 2-2 0 154 0-9 0 63 o-8 0 56 Water - Albumen - Mucilage and starch - Sugar Cellulose - - Mineral matter - For 1 part of flesh-formers in celery there are about 3 parts of heat-givers, reckoned as starch. Lettuce. French, Laitue. German, Lattich. Italian, Lattuga. (Laduca satt-va.) Case 56. The cultivated lettuce may have originated from Laduca scariola, a wild form common in Europe. The lettuce is the most generally used of all the vegetables which are eaten in the uncooked state. The varieties grown may be included in the cos or upright lettuce, and the cabbage or spreading lettuce. Lettuces contain but little nutriment of any kind, except mineral salts, especially nitre. This and other soluble salts are removed from vegetables which require cooking by the water in which they are boiled. A small quantity of a sleep-producing no WATERCRESS. substance, called lactucarin, is found in the stem of the lettuce, particularly when the plant is flowering. Lettuces are a refreshing addition to more solid food. The lettuce contains— In ioo parts. In i lb. oz. gr. Water 96-0 ... 15 157 Albumen- ..... 07 ... o 49 Starch, sugar, and gum - - - I-O ... o 112 Leaf-green and fat - - - - o*2 ... o 14 Cellulose 0-5 ... o 35 Mineral matter - - - - i-0 ... o 70 The quantity of heat-givers and flesh-formers in the lettuce is insignificant. Watercress. French, Cresson d,eau. German, Wasserkresse. Italian, Crescione. (Nasturtium officinale.) Case 56. The watercress is a native cruciferous plant, which grows freely in wet places, especially in shallow streams. It is one of the most popular and most wholesome of all salad plants. It is generally assumed to owe its pungent taste and medicinal value to the presence of an essential oil, containing, like that of mustard, a considerable quantity of sulphur. But it has been shown that the chief constituent of the essential oil of watercress, though rich in nitrogen, contains no sulphur; there is, however, much sulphur, in one form or another, in this plant. Watercress is also remarkable for the quantity of mineral matter which is found in it. The younger shoots of the watercress should be selected; they have a pleasant acidulous yet warm taste. Great care should be taken that they are perfectly clean and free from adhering animal matters. CUCUMBERS. in Watercress contains— In 100 parts. In 1 lb. oz. gr. 93*i 14 392 17 O II9 27 O 189 °5 0 35 07 0 49 »*3 0 91 Water - Albuminoids - Starch, gum, &c. Leaf-green and fat • Cellulose and lignose Mineral matter The dietetic value of the watercress cannot be judged of by the proportion or amount of flesh-formers and heat-givers present, as it depends mainly upon the mineral matters, aromatic oil, and other minor ingredients. Cucumbers. French, Concombres. German, Gurken. Italian, Cocomeri. (Cucumis sativus.) Case 56. The cucumber, like the melon, the vegetable marrow, and the pumpkin, is a tropical plant, belonging to the Gourd Order (Cucurbitacea). These plants flourish best in a rich but open soil; they require much water. When the fruit of the cucumber is grown quickly under glass it is more juicy and digestible than when grown slowly in the open air. Young cucumbers are pickled in vinegar, and are known as gherkins. The rind of the cucumber fruit is indigestible. The fruit itself contains little else besides water, some grape sugar, and a trace of volatile flavouring matter. Peeled cucumbers contain— In 100 parts. In 1 lb. oz. gr. Water 96*2 ... 15 171 Albumen ...... o-2 ... o 14 Sugar (glucose) • - - - - 2-0 ... o 140 Pectose and gum ..... 07 ... o 49 Cellulose 0-5 ... o 35 Mineral matter ..... o-4 ... o 28 in FRUITS. § 5.—Saccharine and Oily Fruits. Many of the vegetable products in this section are esteemed rather for their pleasant or refreshing taste than for any nutritive value which they may be assumed to possess. But though this is the case in our country, the statement is not true generally. The banana and the fig, among fruits rich in sugar, and the coco-nut, among those which abound in oil, are of vital import, ance as substantive articles of diet to the populations of many countries, where the fruits we have just named may be grown easily and abundantly. But, of course, there are some fruits which could never prove of much service as food, owing to the large quantities of water and small quantities of flesh-forming matter which characterise the more juicy and succulent sorts. Yet such fruits are especially valuable on account of their potash salts, the citrate, malate, and tartrate. When fish or meat which has been preserved with common salt, the chloride of sodium, forms the chief article of diet, the blood loses much of its potash compounds, and becomes unhealthy, unless the loss be made up. Now, fresh vegetables and fruits, notably the lemon and the lime, effect this, for the reason above stated. But fruits have a nutritive value, if a small one; and besides that, their flavour and juiciness may serve to stimulate a weak appetite, to give variety and lightness to an otherwise solid diet, and to contribute, in a palatable and refreshing form, much of the water required for the daily needs in digestion and assimilation. In the analyses of fruits which are here given, we have not pretended to enter into all those differences, often very minute, which distinguish fruits from one another. Sometimes the scent and flavour of a fruit altogether defy the powers of chemical analysis; sometimes the same odorous substance is detected in two products of decidedly different fragrance. And then so much of the character of fruits depends upon their texture—a quality that cannot be analysed—that we must rest content with a rather H4 PEARS. Zealand and Australia, it ripens well; yet good English apples have not been excelled in flavour and firmness. The fermented liquor called cider is made from the expressed juice of apples. This fruit is also extensively used in pies, puddings, sauces, and confectionery. Dried or pressed apples are known as Normandy pippins, Norfolk biffins, &c. The apple is an agreeable fruit; it is made very wholesome by baking or boiling. Apples contain a small quantity of a fragrant essential oil, not represented in the following analysis :— In 100 parts. In oz. j lb. gr- 83-0 13 122 0-4 0 28 6-8 I 39 I-O O 70 5-2 O 364 3 *2 O 224 0-4 O 28 Water Albumen ..... Sugar ..... Malic acid ..... Pectose, pectin, and gum Cellulose ..... Mineral matter .... For 1 part of flesh-formers in apples there are 20 parts of heat-givers, reckoned as starch. Pears. French, Poires. German, Birnen. Italian, Pere. (Pyrus communis?) h re The pear, like the apple, the quince, and the is ak» a sample of medlar, belongs to a section of the Rose Order, artificial Essence ' ° , of Pears." called Pomacea. The wild pear-tree is a native of England; it is the origin of the many improved kinds now in cultivation. Some pears are hard and tasteless when gathered, requiring to be stored several months before they become fit for eating. Other varieties ripen early, and very soon afterwards begin to decay. Some pears are adapted for baking, others for stewing. From some kinds the strong fermented liquor known as perry is made. In i lb. oz. gr- 13 203 O 21 I 52 O 7 O 322 O 259 O 21 GOOSEBERRIES. 115 An artificial " Essence of Jargonelle Pears" is much used for flavouring "pear-drops," and other sweetmeats; it is a solution in spirit of amyl acetate. It is thought that the flavour of pears is partly due to this substance. Pears contain— In 100 parts. Water &4'0 Albumen ...... 0'3 Sugar 7-0 Malic acid ...... o'l. Pectose and gum ..... 4'6 . Cellulose ■ - 37 • Mineral matter - - - - - 0'3 The Quince (Cydonia vulgaris) is a native of Southern Europe. Its strongly-flavoured fruits are sometimes added to apple-pies and puddings; they make an excellent marmalade, and also a very agreeable jelly. Quince seeds are rich in mucilage. The Medlar (Cydonia germanica) is a common European plant. Its fruit is not eatable until it has undergone a singular natural change, which is not in reality a process of decay, though it may appear to be so. Some other fruits of the Pomacea, a division of the Rose Order, are eaten. Gooseberries. French, Groseillcs. German, StacJielbeeren. Italian, Uve spine. (Ribes Grossularia.) Case 57. The gooseberry grows wild in Great Britain and in many parts of Northern Europe. It belongs to the same order of plants as the red currant and the black currant. Numerous varieties of the gooseberry have arisen in cultivation. The fruits of these sorts do not differ much in chemical composition, although unlike in size, colour, and flavour. In the North of England this fruit is extensively cultivated, 1 2 n6 CURRANTS, STRAWBERRIES, RASPBERRIES. and has been brought to a great degree of perfection. It is a wholesome fruit, especially when cooked; it makes a good preserve and a tolerable wine. Large quantities of gooseberries are bottled for winter use. The gooseberry contains from 6 to 8 per cent . of sugar, together with about i J^ per cent. of citric and malic acids. Gooseberries contain, as an average— In ioo parts. In 1 lb. 02. gr. Water 86-0 ... 13 332 Albumen 0-4 ... o 28 Sugar 7'0 ... 1 52 Citric acid 1-5 ... o 105 Pectose and gum 1/9 ... o 133 Cellulose 27 ... o 189 Mineral matter O'S ... o 35 For 1 part of flesh-formers in ripe gooseberries there are about 20 parts of heat-givers, reckoned as starch. The quantity of flesh-formers in 1 lb. of gooseberries is insignificant . The Black Currant is Ribes nigrum, while the Red and White Currant both belong to another species, R. rubrum. Cultivation has greatly improved the quality and increased the size of these fruits. Many varieties of red currant are grown. In composition these fruits do not differ much from the goose- berry. They are not nearly related to the small dry fruits called currants, which are produced by a small vine. The Strawberry, though containing more water than the gooseberry or the currant, has a richer fragrance and flavour. The cultivated varieties have arisen from several species of Fragraria, but mainly from the wild F. vesca, the common straw- berry of our English woods. The Raspberry (Rubus idaus) is a native of Britain. Several varieties of the cultivated plant are grown, the fruits being either red or pale amber. From the raspberry, as well as from the gooseberry and currant, jam, jelly, and wine of good quality GRAPES. 117 are made. Strawberries are often preserved with sugar, but this fruit is perhaps better appreciated as a dessert fruit. The Blackberry (Rubus fruticosus) and the Dewberry (R.casius) are wild fruits which would repay cultivation. The flavour of some of the wild sorts is decidedly superior to that of others, and these may be made to yield a good preserve and a full-flavoured wine. The Barberry (Berberis vulgaris) is a native of Britain. Its bright red fruit has an acid taste, but makes a pleasant preserve. The Bearberry (Arctostaphylos uva-urst) is a British plant belonging to the Heath Order. Its red berries are eaten by grouse. The Bilberry (Vaccinium myrtillis) and Whortleberry (V. uliginosum) are common in many woods. Their fruits may be made into a preserve. The Cranberry is nearly related to the bilberry. The fruits of several species are used in the form of jams and in tarts. Large quantities of cranberries are imported from Russia and North America. The Elderberry is the fruit of Sambucus nigra, a native tree. A richly-flavoured wine is made from elderberries. Grapes. French, Raisins. German, Weintrauben. Italian, Uve. ( Vitis vinifera.) Casess. The vine was very probably originally a native of Western Asia and the region south of the Caspian. It is pro. fitably grown between 300 and 40 0 north latitude. By long-continued cultivation of the original plant in different soils and climates, numerous varieties of the vine have arisen. Most of these kinds are grown for wine-making in France, Ger- many, Southern Europe, the Cape, Australia, &c. Some varieties yield fruits, which are simply dried. These are known as Valentia, 120 RHUBARB. Apricots (the fruit of Prunus armeniacd) closely resemble peaches and nectarines in composition, but generally contain rather more sugar. Rhubarb. ( Rheum rhaponiicum.) Case 59. Although used as a fruit, it is scarcely necessary to say that rhubarb is the stalk or petiole of the leaf. The plant furnishing this agreeable and succulent food is a hardy perennial, from the Volga river, and has been grown in this country since 1573. There are several varieties of Rheum rhaponticum in culti- vation, and it is possible that R. vndulatum may also be amongst the different kinds of rhubarb in use. The rhubarb belongs to the Buckwheat Order (Folyponacea). The agreeable taste and odour of rhubarb are not brought out till the leaf-stalks are cooked. But when the expressed juice of these is allowed to ferment, it yields, with proper treatment, a delicious wine. The chief nutrient in rhubarb is the sugar (glucose), which amounts to about 2 parts in 100 of the fresh stalks. Its sour taste is due to oxalic acid, or rather to the acid oxalate of potash; oxalate of lime is also present. There are some conditions of the human body (the oxalic-acid diathesis) in which it is probably wiser to avoid eating rhubarb and other plants, as sorrel, in which oxalic compounds predominate. The composition of the freshly-cut leaf-stalks of a red variety of rhubarb which had been grown in the open air, and were in good condition for use, is here shown :— Composition of Rhubarb. In 100 parts. In i lb. Water 95*1 Albumen - 0-9 Sugar (glucose) and gum - - - 2-i Oxalic acid o-3 Cellulose I*l Mineral matter - - - - - 0-5 ... O 35 As i lb. of rhubarb contains less than 1 oz. of solid matter, I5 94 o 63 o 147 o 21 o 77 FIGS. 121 and as even of this solid matter more than one quarter is not nutritive, it is obvious that the food value of this vegetable is very small. It is, indeed, esteemed mainly for its pleasant flavour, which is due to a trace of some volatile matter, too small to be identified, along with a little grape sugar and the acidulous com- pound already mentioned. Figs and dates next claim attention. They are imported in a partially dried condition, and consequently are far more nutri- tious, weight for weight, than any of the fresh fruits we have been considering. Figs. French, Figues. German, Feigen. Italian, Fichi. (Fiats carica.) Case 59- The Fig Order includes several important trees, such as the mulberry and the banyan: one kind of fig-tree (F. elastkd) yields much of the india-rubber of commerce. The sycamore fig (F. sycomorus) is a small fruit, common in Egypt, from another species. The edible fig is a native of the Eastern Aral, the Caucasus, Syria, Persia, Asia Minor, and perhaps of South-Eastern Europe and Northern Africa; it has been long grown in the regions of the Mediterranean. The fig is cultivated in warm and sheltered situations in the south of England. Large quantities of dried and pressed figs are imported into England They contain much sugar, and but little water. The numerous so-called seeds in the fig are indigestible, and some- times have an irritant action. Dried Turkey figs contain— Water Albumen ..... Sugar (glucose) .... Starch Pectose and gum.... Fat Cellulose ..... Mineral matter .... ioo parts. In 1 lb. oz. gr. 17-5 2 350 6-i O 427 57-5 9 88 3-0 O 2IO 5-4 O 378 0-9 0 63 7-3 I 83 2-3 0 161 iai DATES. For i part of flesh-formers in dried figs there are quite 10 parts of heat-givers, reckoned as starch. One pound of dried figs might produce at the most nearly i oz. of the dry nitrogenous substance of muscle or flesh. Mulberries are the fruit of a beautiful tree (Morus nigra) belonging to the Fig Order, of Western Asia, extensively grown in Europe. Mulberries contain more acid than most dessert fruits, but possess a very characteristic flavour. Dates. French, Dattes. German, Datteln. Italian, Datteri. (Phanix dactylifera.) Cas= 59. Dates are the fruit of a palm. The tree has been introduced into Southern Europe, but it is a native of North Africa. The cultivation of the date-palm is of great antiquity. The fruits of this palm grow in clusters, weighing 20 lb. or more; they form an important food in Egypt and Arabia. Dates pounded and pressed into a kind of cake are much used by the inhabitants of Northern Africa, and by travellers through the Sahara Desert. Dates contain more than half their weight of sugar, but there is a fair amount of flesh-formers present as well. Dates, without the stone, contain- Water - Albumen Sugar Pectose and gum Fat Cellulose Mineral matter In 100 parts. In 1 lb. oz. gr. 20-8 3 H3 6-6 1 25 54-0 8 280 12-3 ~ 1 424. 0'2 0 14 5-5 • 0 385 1-6 0 112 For 1 part of flesh-formers in dates there are 10 parts of heat- givers, reckoned as starch. One pound of dates might produce about 1 oz. of the dry nitrogenous substance of muscle or flesh. CAROB OR LOCUST BEANS. 123 Bananas. (Musa sapientum.) Case 60. The banana is the fruit of a handsome plant, grown almost everywhere in the tropics; it is a most important article of food in many hot countries. Bananas have been cultivated in India and China from very remote ages. Another species or variety of this plant (M. paradisiaca) yields the plantain, a fruit almost identical with the banana. The banana is a nutritious food, having less water and more nitrogenous matter than is commonly found in fresh fruits. It contains, when ripe, much sugar, but very little starch. The banana is a very productive plant. Its fruit grows in clusters of 100 to 200; a bunch of them will often weigh 50 lb. They are imported, to some extent, into this country, as a dessert fruit. Fresh-peeled bananas contain— Water - Albumen Sugar and pectose Fat Cellulose Mineral matter 1oo parts. In 1 lb. oz. gr. 73'9 .. II 361 4-8 O 336 197 .. 3 66 o-6 .. 0 42 0-2 0 14 o-8 0 56 For 1 part of flesh-formers in fresh-peeled bananas there are 4 parts of heat-givers, reckoned as starch. One pound of bananas might produce, at the most, J^ oz. of the dry nitrogenous substance of muscle or flesh. Our next fruit is scarcely used at all in this country, except as food for cattle and horses; but it is of interest as a legume con- taining much sugar. Carob Beans. ( Ceratonia siliqua.) Case 60. Carob beans or locust beans, called also algaroba and St. John's bread, are really entire pods, not merely beans or seeds. ORANGES, ETC. 125 Bigaradia) ; the lime (C. Limetta); the citron (C. medico); the lemon (C. Zimonum); the shaddock, pomaloe, or forbidden fruit (C. decumana) ; and the cumquat (C. japonica), are all species of the same genus, and are all characterised by the presence of similar fragrant essential oils in the peel or rind, and by varying quantities of citric acid, citrate of potash, and sugar in their fleshy pulp. Besides the flavours they impart to other foods, many of the fruits we have named are of direct alimentary and medicinal value. The orange and its various products, in the form of orange marmalade (into which Seville oranges are generally introduced), orange wine, and candied orange-peel are the best known. This fruit is imported into England in vast quantities from Malta, the Mediterranean coasts, Lisbon, and the Azores— very fine fruit being brought from the island of St. Michael. The orange can, however, be enjoyed in perfection only when taken perfectly ripe from the tree. The imported fruits are always gathered in an unripe state. The orange-tree yields another essential oil besides that in the fruit—the oil of neroli being obtained from orange-flowers. The tree is evergreen, and its rich, green, glossy leaves, and masses of golden fruit, form a beautiful feature in the landscape of many parts of Italy. An orange of good quality should not lose more than one-fifth its weight by the removal of the peel. The peeled fruit contains about 86 per cent. of water, 8 to 10 per cent. of sugar, and small quantities of citric acid, citrate of potash, albumen, cellulose, &c. We shall have to recur to the subject of the Orange Order when discussing the "flavourers," in the Fourth Part of this book, on Food Adjuncts. The pomegranate (Punka Granatd), the prickly pear (Opuntia vulgaris), the jak fruit of Ceylon (Artocarpus integrifolia), the bread-fruit of the Moluccas and other islands (Artocarpus incisa), the tamarind, the mangosteen, and many other fruits, which we have no space to describe, are of considerable importance in different parts of the world—some of these fruits forming the FILBERTS. 127 excellent pickle; a delicate sweetmeat is prepared by boiling them in sirup. Walnuts contain a sweet oil much used in Southern Europe for food, and, under the name of nut-oil, for painting. The marc of walnut-kernels, or walnut-cake, is a good cattle food. Walnuts in the shell yield one-third their weight (about 36 per cent.) of peeled kernels, which are the crumpled cotyledons, or seed-leaves. These when quite fresh contain— 00 parts. In 1 lb. oz. gr. 44*5 7 53 12-5 2 0 8-9 .. 1 185 31 *6 5 24 o-8 0 56 17 0 119 Water Albumen ..... Mucilage, &c .... oa Cellulose Mineral matter - For 1 part of flesh-formers in walnut-kernels there are about 6% parts of heat-givers, reckoned as starch. One pound of walnuts cannot produce more than 2 oz. of the dry nitrogenous substance of muscle or flesh. Case 63. The Hazel-Nut, the Filbert, and the Cobnut are produced by Corylus avellana, and the cultivated varieties of this native tree. The best hazel-nuts come from Spain, and are known as Barcelona nuts. Cobnuts and filberts are largely grown in Kent. Fine filberts, freshly gathered and ripe, contain rather more than half their weight of edible kernel. This, if analysed before drying, just as it is taken from the shell, gives the following results:— Composition of Filbert Kernels. Water - Albumen, &c- Oil ... Mucilage, starch, Sec. Cellulose Mineral matter 00 parts. In 1 lb. oz. gr. 48-0 7 297 8-4 I 151 28-5 4 245 ii-i 1 340 2-5 0 175 i-5 0 105 For 1 part of flesh-formers there are here about 10 parts of heat-givers, reckoned as starch. 128 GROUND-NUTS—PISTACHIO-NUTS. Cases 6, & 63. Another well-known oily nut is the Sweet Almond, the produce of a small Mediterranean tree (Amygdalus communis), belonging to a section of the Rose Order. The so-called Jordan almonds come from Malaga.* The almond does not ripen pro- perly in this country. The brown coat of the almond kernel is indigestible, and should be removed by pouring boiling water on the kernels and peeling them. Almonds correspond in general character to filbert kernels, but are much drier when imported than when gathered. The bitter almond is produced by a mere variety of the same tree, but it contains a peculiar ferment called emulsin, which is capable of changing a nitrogenous matter, present in the bitter almond and the sweet, into prussic acid, the essential oil of bitter almonds, and glucose. This change occurs when bitter almond meal is mixed with water and gently warmed. Case46. The Ground-Nut, or pea-nut (Arachis hypogaa), though an oily seed, really belongs to the leguminous plants, and has been already described in the section on pulse. In addition to 50 per cent. of oil it contains about the same amount of nitrogenous matter (24V5 per cent.) which usually occurs in beans and peas. Composition of Ground-Nuts (shelled). In 100 parts. In 1 lb. oz. gr. Water 7'5 ... 1 87 Casein, &c. 24/5 ... 3 403 Oil 50-0 ... 8 o Mucilage, &c. ..... 11-7 ... 1 382 Cellulose and lignose .... 4-5 ... o 315 Mineral matter ..... i-8 ... o 126 For i part of flesh-formers in these seeds there are 5 parts of heat-givers, reckoned as starch. Case 63. The Pistachio-Nut (Pistacia vera) is the produce of a small Mediterranean tree. The fruit resembles a small almond, * In Case 61 are shown fifty varieties of almonds cultivated in France. COCO-NUTS. 129 but has a bright green kernel, which owes its colour to chloro- phyll, or leaf-green. The kernels possess a taste not unlike that of the sweet almond; they are much used in French confec- tionery. The following analysis represents the Composition of Pistachio-Kernels. In 100 parts. In 1 lb. oz. gr. Water ...... * 7-4 ... 1 80 Albuminoids - - - • - - 227 ... 3 272 Oil 51-1 ... 8 77 Mucilage, &c. 13-0 ... 2 35 Cellulose 2*5 ... C 17$ Mineral matter ..... 3-3 ... o 231 For 1 part of flesh-formers in pistachio-kernels there are 6 parts of heat-givers, reckoned as starch. One pound of Pistachio-kernels might produce at the utmost 3^ oz. of the dry nitrogenous substance of muscle or flesh. Case 64. The Olive (Olea europaa) contains most of its oil outside the seed, in the green fleshy pericarp, which is sometimes eaten, the whole fruit being preserved in brine. Case 64. The Hickory-Nut is produced by a North American tree (Carya alba), which belongs to the jFuglandacea. It re- sembles a small walnut. Another species of the same genus, C. olivaformis, yields a similar nut, the pecan or picary nut. Case 64. The nut of the Cocos nucifera, commonly called cocoa- nut, but which we shall here term the coco-nut (to distinguish it from cacao), is a very characteristic fruit, rich in oil. Coco-Nut. French, Coco. German, Cocosnuss. Italian, Coccc. (Cocos nuciferaS) The lofty and most useful tree which yields the coco-nut is a palm, now largely cultivated in many tropical islands, and on many tropical coasts. A single tree will bear from 80 to 100 fruits. K 13° DIKA BREAD. The outer husk of the coco-nut affords a strong fibre called "coir," from which mats, brushes, and cordage are made. The shell of the nut is formed into bottles and drinking-cups, and gives, when properly burnt,-a very valuable charcoal. The spirit called "arrack " is distilled from the fermented juice, or "toddy," of the flowering branch of the coco-nut palm, while the milk or liquid part of the kernel is, when fresh, a nourishing and pleasant beverage. The solid white kernel of the coco-nut is rich in oil, which is expressed and used for many purposes. The solid kernel weighs, when fresh, about i lb., and has the following composition :— Case 64. In 100 parts. In 1 lb. oz. gr. Water • • • 46-6 7 200 Albumen, &c. - - 5-5 O 38S Oil .... 35-9 •• 5 32S Sugar, &c - 8-1 I 130 Cellulose - 2-9 O 203 Mineral matter fO O 70 For 1 part of flesh-formers in this kernel there are about 15 parts of heat-givers, reckoned as starch. One pound of coco-nut kernel could form, at the utmost, about 7/% oz. of the dry nitrogenous substance of muscle or flesh. Dika Bread. (Irvingia Barteri.) Case 64. The food known as dika bread is made from the fruit of a tree belonging to the Quassia Order. This tree grows in profusion on the west coast of Africa, from Sierra Leone to the Gaboon: although not related to the mango-tree of India it is called the wild mango. The fruit from which dika bread is made is about the size of a swan,s egg. It contains a large white almond-shaped kernel. 13a MILK AND DAIRY PRODUCE. PART III.-ANIMAL FOODS. In the various parts of animals, and in the products of animal origin which are used as food for man, there are present many kinds of nutrients identical, or practically identical, with those found in vegetables. In both kingdoms albuminoids, oil or fat, and phosphates and potash salts abound. But, on the other hand, neither starch nor cellulose occurs in animal foods, while sugar is generally absent, or else exists in mere traces, with the solitary exception of milk. Yet there are some sub- stances which are distinctive of animal tissues, not occurring at all in plants. Such are the ossein of bones, the cartilagin of cartilages, and the similar nitrogenous compounds of connective tissue and skin. Add to these the haemoglobin of the blood, and some of the rarer and less thoroughly understood con- stituents of the brain and bile, and we have the chief distinctive compounds of animal structures. It will be seen further on that animal foods are usually richer in nitrogenous matters and in fat than vegetable foods; and also, that on the average, they contain a smaller percentage of water, when the comparison is made with materials in the fresh state. § i.—Milk and Dairy Produce. As the natural food of the young of the mammalia, it is found that milk may be regarded as a model food. It furnishes MILK. 133 all the nutrients required by the growing immature animal; and it furnishes these nutrients in due proportion. Cows' milk is nearly opaque under ordinary conditions of light; it has a faint tinge of straw-yellow, which becomes more marked when the animal has abundance of green food. Milk has a soft, slightly sweet taste, it has also a faint animal odour when warm and fresh. When milk is allowed to stand some time the first change which occurs is the rising of the cream, owing to the lower specific gravity of the globules of milk-fat, which at first are scattered uniformly through the milk. These minute globules—easily seen under the microscope—are the main cause of the white opacity of milk; but there are also many still more minute globules of casein, the chief nitrogenous nutrient of milk. The amount of cream which rises depends upon many conditions. The first of these is the richness of the milk in the milk-fat; other conditions are: temperature—a low temperature being favourable to the separation of the cream —a considerable bulk of liquid, a wide vessel, and complete freedom from agitation, are also favourable conditions. The chief losses which milk suffers when skimmed are the removal of most of the fat, and about one-sixth of the casein. The next change which milk suffers on keeping is that of turning sour. This occurs specially in hot weather, and first affects milk which has not been kept in clean vessels and in pure air. The souring of milk, however brought about, is marked by the presence of an acid—lactic acid, which is formed from the peculiar sugar of milk known as lactose. It may be retarded by the addition of a little carbonate of soda, or, as has been recently discovered, by a small quantity of boracic acid. As casein is separated from solutions by lactic acid, as well as by nearly all other acids, milk which has turned ceases to be of uniform appearance and opacity. Curds separate—these curds consist- ing of casein, but entangling also, as the substance becomes insoluble, much of the milk-fat and of the phosphates. This -' 136 CREAM. In Sweden, Norway, and Denmark sheep,s milk is used; in Switzerland, much goats, milk; in Tartary, mares, milk; camels, milk amongst the Arabs, and reindeer,s milk in Lapland. In many of these countries milk, from one source or another, forms a very important part of the food, not only of children, but of adults, and a much greater quantity is consumed than is the case with the labouring classes in the British Isles. There are many parts of the rural districts of England where milk is seldom seen, not being used generally even with tea. It is consumed more extensively in Ireland than in England, in proportion to the population. In Tartary, mares, milk is allowed to ferment, whereby alcohol and carbonic acid gas are formed from some of the sugar present; the casein separates at the same time in curds. Such fermented milk is called koumiss, and is found to be a wholesome and generally nutritious food. It is said to possess even some special value in consumption. An imitation of it is prepared in London from sweetened cows, milk Cream. The cream which rises from cows, milk when the liquid is cooled and at rest, is not constant in amount or composition. If water be added to milk the cream rises more quickly, but is not increased in absolute amount. The cream usually measures 12 per cent., or ranges within 10 and 15 in average Case 65. samples of milk—the milk being placed in tubes half-an-inch in diameter, where it remains twenty hours before the degrees occupied by the cream are read off. Some notion of the average composition of cream may be gathered from the following analysis, but the range of variation is great, the water alone varying between 45 and 65. CONDENSED MILK. 137 Constituents of Cream. In ioo parts. Water 55-0 Casein .......... 6-0 Milk-fat 363 Milk-sugar- ......... 2*5 Mineral matter ......... o*2 Skim Milk. When the cream which has risen on milk is removed, the liquid which remains is poorer in milk-fat and in total solids, but its percentage of milk-sugar is increased. It is a light and digestible food, but the ratio between its flesh-forming and heat- giving nutrients is different from that of fresh milk, the heat-givers being much lower. Its composition will vary much according to the extent to which the cream has risen and been removed. The following is an analysis of skim milk :— Composition of Skim Milk. In 100 parts. Water - 89^0 Casein .......... 4/3 Milk-fat o-4 Milk-sugar- ......... 5-5 Mineral matter o-8 Preserved and Condensed Milk. Case 65. Although there are several ways of treating milk so that it may be preserved sweet and wholesome for some time, or reproduced for use very easily and simply, yet there is but one preparation of this kind which is extensively used. This is called condensed milk; but in reality the milk has not only been con- densed by the removal of a large proportion of its original water, but it has received a considerable addition of cane-sugar, to pre- serve it. Thus it happens that this condensed milk, or preserved 138 ADULTERATION OF MILK. milk, cannot take the place of milk as a model food, the proportion of heat-givers to flesh-formers being too high. Preserved milk is generally prepared by evaporating milk, after the addition of cane- sugar, till it acquires a thick consistence. The pale straw-coloured sirup is poured into tins, which are then closed from the air by soldering. During evaporation some of the fatty matter is dissi- pated along with the vapour of water. The milk presents these results on analysis:— Composition of Preserved Milk. In 100 parts. Water 24-0 Casein .......... iS-a Milk-fat 11 "5 Milk-sugar - - 177 Cane-sugar- ......... Tf6 Mineral matter .*---.-.. 2'o For i part of flesh-formers in this preserved milk there are 6 parts of heat-givers, reckoned as starch. Adulteration of Milk. Caie66. The removal of cream and the addition of water are the only ways in which milk is commonly impoverished. The removal of cream shows itself in the thinner and less opaque appearance of the milk; the addition of water produces the same effect. As milk-fat, the chief part of cream, is lighter than water, its partial removal from the milk makes the specific gravity of the remaining milk greater: by the subsequent addition of water the specific gravity may be lowered down to that of the original milk. Thus it is clear that the specific gravity of milk, taken alone, is valueless as a test of its quality. The indications of the "gravity lactometer" should be combined with the use of a set of gra- duated tubes in which to ascertain the number of measures of cream which rise from 100 measures of milk in 24 hours. And it is also advisable to ascertain the opacity of the sample by means of the lactoscope. Chemical analysis, of course, affords a BUTTER. 139 more complete proof of the sophistication of milk. The total solids, and also the solids not fat, should be ascertained. A hundred grains of milk should leave, when carefully dried up, from 12 to 14 grains of solid substance, including milk-fat, casein, milk-sugar, salts, &c.; and the solids other than fat ought to amount to 9 or 10 grains. It has been argued that the removal of cream from, and the addition of water to milk, are not adulterations injurious to health. As, however, these operations lower the feeding value of the milk considerably, and also seriously alter the relation between the heat-givers and flesh-formers of this model food, the above posi- tion cannot be maintained. It must also be borne in mind that there are many children whose daily allowance of milk, supposing it to be of good quality, barely suffices to sustain life: when this milk has been lowered by one-fourth or one-third of its original feeding value, it is not difficult to foretell the results. The statements that chalk, brains, gypsum, &c., are used to thicken milk are almost entirely devoid of foundation. Milk has sometimes been the means of spreading disease, either through its direct contamination with the specific poison of disease during the milking of the cows, or by means of the water used in rinsing the vessels employed, or in diluting the milk. The milk itself is sometimes unwholesome from the outset, owing to the unhealthy condition of the cow. Butter. French, Beurre. German, Butter. Italian, Burro. Although butter consists chiefly of milk-fat, yet it contains by no means inconsiderable quantities of the other constituents of milk. It may be obtained from cream most readily, but also by the direct churning of milk. Butter made from sweet cream has a more pleasant taste and keeps good longer than that made from sour cream: this difference is caused mainly by the presence of much casein or curd in the butter from sour cream. 140 BUTTER. Much butter is now made in factories, in the United States of America, in Sweden, and elsewhere. By scrupulous attention to the purity and healthiness of the milk received, to the absolute cleanliness of the vessels used, and to the temperature and other conditions essential for a successful result, an excellent quality of butter is uniformly produced. The exact temperature, both in the rising of the cream and during the churning process, is always maintained; ice and currents of warm water being used as required. The taint, or unpleasant and peculiar taste which so much butter possesses, can be avoided when all necessary precautions are taken to prevent the access of any kind of odorous vapours to the milk or cream. Nothing is so strongly absorptive of odours or volatile flavours as butter. It absorbs and retains the vapours from cheese, from meat, and especially from every kind of decaying vegetable or animal matter. If improper or strongly-flavoured food has been given to the cows, it is in the butter made from the milk that the taste of that food will be most clearly perceived. The best temperature for churning lies between 570 and 61 0 Fah.: 6o0 is a fair degree of heat. Sometimes cream is heated to a much higher temperature first—say 1800 Fah.—and then cooled down to 6o° Fah. before being churned. Butter thus made keeps well. It is generally considered that 1 lb. of butter can be made from 23 pints of milk. Butter always has some salt added to it: this salt must be quite pure. If it be not free from magnesium compounds, it will give a bitter taste to the butter. Even fresh butter has some salt in it—from j£ to 2 parts in the 100. Salt butter ought not to contain as much as 8 per cent., but more has been found in inferior samples. If butter is to be kept some time or exported, it receives, besides salt (2 to 5 per cent.), a small addition of sugar—not, however, more than 8 oz. to the hundredweight. The purity and goodness of butter can be ascertained by means of the microscope, chemical analysis, and certain special BUTTER. 141 tests of melting points and specific gravity. But these tests cannot be applied except by experienced analysts. Still it is easy to learn a good deal about some of the adulterations practised on butter, by simply melting a portion of it in a glass tube plunged in hot water. After a time the water, the curd or casein, and the true butter or milk-fat, separate into layers. The water remains lowest: on its surface, and mingled with a portion of the melted fat, lies the curd; while the remainder of the fat constitutes a layer resembling oil, and remaining at the top. Now, as there should not be more than 8 to 13 per cent. of water in good butter, the watery layer should not exceed in volume one-eighth of the whole butter. Nor should the casein, or curd, be very conspicuous. Water has, however, been found to the extent of 30 per cent. or more in some samples of butter, while salt often occurs also in great excess. Unfortunately, also, imitations of butter are now made on a large scale, and may be used to adulterate butter without being easily recognised. If they are sold under the names of "butterine" and "oleo-margarine," pur- chasers know that they are not buying butter, though they may be purchasing a wholesome and cheap substitute for it. But these purified fats (bone-fat, horse-fat, &c.) are sometimes imported into England as Brittany or Normandy butter, and are also used for the fraudulent sophistication of genuine butter. The flavour of the true product is given to them by working them up with butter-milk, and it is difficult to recognise their origin. Case 67. We cannot give an exact analysis of fresh butter which shall fully represent its components; but we may take the follow- ing figures as showing the average proportions of its most important constituents when of good quality :— Water - Casein - Milk-fat - Milk-sugar Common salt In 100 parts. IO-0 In 1 lb. oz. gr. I 262 I-O 877 •• O 70 14 14 0-3 0 21 i-0 O 70 CHEESE. 145 popular prejudice still demands a high colour in cheese, as the entire abandonment of the use of annatto is very desirable; its employment introduces impurities into the cheese, and does not improve the flavour in any way. The digestibility of cheese varies with its texture, its age, and its composition. Generally speaking, it cannot be said to be easily attacked by the gastric and intestinal secretions. But a moist, crumbly cheese, fairly rich in fat, is more rapidly and completely digested than the drier and more nitrogenous skim- milk kinds. By various modes of preparation, such as grating and admixture with starchy matters, cheese may be made more useful and available for food. It should be eaten along with bread, rice, or other kinds of food rich in heat-giving nutrients, in which cheese is deficient. It requires some time before persons unaccustomed to eat cheese as a substantive article of the daily diet can derive full advantage from its nutritive properties. The presence of much bone-forming material in cheese is worthy of remark. Some kinds of cheese, especially those which contain most milk-fat, and are not of a very close texture, acquire a strong odour and flavour by keeping. Both the casein and the milk-fat are then partly decomposed, the former yielding ammonia and ammonium sulphide, and the latter giving rise to butyric, caproic, and other acids. The blue mould, or mildew, which makes its appearance in old and very ripe cheeses, such as Stilton, is a vegetable fungoid growth. Cheeses are also liable to the attacks of minute animals. The common cheese-mite is Acarus domesticus; the cheese-fly, Piophilus casei, deposits its eggs in the cheese, where they reach the larval stage, becoming the cheese-maggots known as "jumpers." It is scarcely necessary to state that all these forms of animal and vegetable existence cause a con- siderable consumption of the food-substance of the cheese on which they live, lowering its nutritive value. Usually, however, the decayed cheeses to which these remarks apply are consumed EGGS. *47 The white of a hen,s egg has about the following composition :— Water - . . . b £•§"*• Albumen ----...... 12-0 Fat, sugar, extractives, and membranes • - - - 2-o Mineral matter ft The yolk of a hen,s egg shows a much greater degree of richness than the white. It contains—• In ioo parts. Water - - . . . . - . . . 51-j Casein and albumen - - - - . . . . 15-0 Oil and fat --....... 30-0 Pigment, extractives, &c. - 2-I Mineral matter ..- 1-4 The mineral matter of the contents of hens, eggs, though small in quantity, is rich in quality, consisting, as it does, mainly of phosphates of lime, potash, soda, magnesia, and iron. The mixed whites and yolks of hens, eggs (the shells being excluded) contain— In 100 parts. Water - Albumen and casein Oil and fat - Membranes and extractives Mineral matter 717 14-0 IIX) 2-0 1 *3 In i lb. oz. gr- II 207 2 I05 I 332 O I40 O 91 Eggs are very nutritious articles of food. They contain about as much flesh-forming and heat-giving substances as an equal weight of butchers, meat. For 1 part of flesh-formers present in them there are nearly 2 parts of heat-givers, reckoned as starch. One pound of the mixed yolks and whites can produce at the most a little more than 2 oz. of the dry nitrogenous substance of muscle or flesh. One pound of hard-boiled eggs, if completely oxidized, could set free a force equal to 1,415 tons raised 1 ft. high. The greatest amount of work outside the body which it could enable a man to l 2 i48 BUTCHERS MEAT. perform is 283 tons raised 1 ft. high. The remainder of the stored-up force in this amount of food will be in part unexpended, but much of it will be used in keeping up the heat and internal activity of the body, and in the repair of its tissues. One pound of white of egg can set free force equal to no more than 357 tons raised 1 ft. high, and can enable a man to perform external work equal to only 71 tons raised 1 ft. high, whilst 1 lb. of yolk of egg can set free force equal to 2,051 tons raised 1 ft. high, and could enable a man to perform external work equal to the raising of 410 tons 1 ft. high. The number of eggs imported into Great Britain is enormous. During the first quarter of 1876 it was something like 17^ millions. It has been calculated that 18 eggs would contain an amount of flesh-forming substance and of other nutrients suffi- cient for the various needs of life in an adult man for one day. It would be necessary, in order to provide the same amount of albumen from such a fruit as the pear to consume no less than 70 lb. It would be difficult to find a more striking illustration than this of the concentrated character, so far as nitrogenous or flesh-forming substance is concerned, of the egg. § 3.—Butchers, Meat. The variations in composition between different joints from the same animal are considerable. Add to this the fact that there are numerous additional differences, due to peculiarities of individual animals, to race, to age, and to the modes and materials of feeding, and we shall find it easy to account for the great discrepancies between different analyses of the same kind of meat. The variations in the amount of fat are the most conspicuous, and influence, of course, the proportions of other meat-components greatly. A piece of meat may con- BUTCHERS MEAT. 149 tain but 5 per cent. of fat, when it will be found to possess 70 per cent., or perhaps 75 per cent. of water. But should 50 per cent. of fat be present (a fat mutton or pork chop may contain more) then the water may not be higher than 38—the rule being, the more fat the less water. If, then, nitrogenous or flesh-forming material be wanted, the leanest meat will furnish this, along with a considerably greater proportion of saline or mineral matter than is found in fat meat. Where heat-givers and force-producers are in demand, as in cold countries, and during fairly hard work, then the fatter meats and bacon are at once more suitable and more economical. There are some signs by which the good quality of butchers' meat may be generally judged. Amongst these, in the case of mutton and beef, we may name a rich, bright, and uniform colour, and a firmness of texture, quite free from flabbiness, though moderately soft and elastic. Damp and clammy meat' with a tendency to exude moisture is generally unwholesome. Very young meat, from animals forced to a large size in a very short time, is neither agreeable in taste, nor easily digested. The rapid rearing and fattening of animals, though profitable to the farmer, produces a poor and inferior quality of meat. The flesh, or true muscular fibre, is not properly developed, while the connective and other gelatinous tissues are present in super- abundant proportion. Meat is tender, if properly cooked, before the rigor mortis has set in, but it must be kept some days after that rigidity of the muscles has occurred if it be required to possess this valuable quality. Still, it is better for meat to be somewhat tough rather than unwholesome owing to the commencement of putre- faction, which so readily occurs in hot weather. A word should be said here concerning measly and braxy meat.* The former condition, when well marked, is easily * For a model of a piece of measly pork, see Case 71. 150 BUTCHERS MEAT. detected by the eye. It is caused by the presence of parasitic animals—species of Trichina and Cysticercus. It is believed that these embryonic forms of animals, in part belonging to the genus Tenia (tapeworms, &c.), are destroyed by the heat of boiling or roasting meat. Care should be taken to avoid imperfectly cooked pork, or ham, or sausages; as well as any vegetables, as salad plants, which have not been thoroughly washed Flesh- meat which is measly is also peculiarly liable to decomposition, and becomes objectionable on that score. The same may be said of braxy meat—the flesh of unhealthy or diseased animals which have been slaughtered in order to anticipate their imminent death, and the consequent total loss of their flesh as human food. Moreover, braxy meat may contain the specific poisons of various diseases, as well as the medicinal agents administered to the sick animal. The various processes of cooking meat influence its com- position and digestibility differently. Roasting before an open fire is far preferable to baking. If meat be boiled, it should be plunged in boiling water for a few minutes, and then such an amount of cold water added as will suffice to lower the heat of the water to about 1700 Fah., which temperature should not be much exceeded during the whole time of cooking. Meat loses considerably both in digestibility and flavour when twice cooked. Salt meat is less nutritious and wholesome than fresh, except in the case of bacon and ham. The liquor in which mutton has been boiled contains valuable mineral and organic matters which ought not to be wasted. The liquor in which salted beef has been boiled is not available for food, except to a small extent, owing to the immense quantity of common salt which it contains. This salt in excess has an indirect injurious action on the human system, as explained on p. 24. The chemistry of those changes which occur during the processes of cooking cannot be dwelt upon here. But those changes are mainly the following: the removal of much water in the form of vapour and as gravy, the latter containing MUTTON. 151 the soluble organic and inorganic matters of the joint. Much gelatin, too, is found in the gravy, this substance being produced from those tissues of the meat which are not true muscular fibre, and which are rendered soluble by a moist heat. Much fat is melted out of the adipose tissue, and certain slightly carbonised matters, or dark-coloured substances, are formed out of the carbonaceous and nitrogenous constituents of the meat. To these dark-coloured materials, which are but little understood, the aroma, or flavour and odour, of a roasted joint are greatly due. They may be compared to the similar products found in the crust of bread, and in baked pastry and puddings. The general tendency of the process of roasting meat is to render it more soluble, digestible, and nutritious. We now come to the question of the composition of the different kinds of meat in general use as food. Our information on this subject being still imperfect, it will probably be best to give somewhat minute details about a single kind of butchers, meat which we have lately submitted to special examination, and then to present a more general view of the composition of the other kinds of flesh-meat. Case 69. A mutton-chop shall be the subject of our illustration. It contained, when quite fresh, a proportion of bone amounting to 8 per cent.—perhaps a rather lower proportion than usual. When submitted to careful analysis, it gave the following results when the flesh and fat were taken together in the fresh state for analysis :— Water • Albumen Fibrin (true muscle) Ossein-Hke substances Fat ... Organic extractives - Mineral matters Other substances In 100 parts. 44-1 In 1 lb. oz. gr. 7 24 17 O 119 5-9 0 413 0 84 I-2 42-0 i-8 6 315 0 126 2-3 0 70 0 161 '5* MUTTON. The bone of this mutton-chop was analysed, and gave the following results :— In 1oo parts. In 1 lb. Water oz. gr. 32-2 5 W Ossein ..... - - 187 2 434 Fat 9-0 1 193 Phosphate of lime ... 34-1 5 200 Carbonate of lime,' &c - 6-0 0 420 A recently-published analysis of a mutton-chop described as "lean" showed very different results to those we have given above. "The more lean, the more water ;" and consequently the number representing the percentage of water was 75'5 ; the fat was set down as 8-6; the albuminoids as 10-5 ; the ossein-like substances as ro; and the mineral matter as 3-5. To show the influence of cooking upon a mutton-chop, we may cite two analyses, in one of which (a) the gravy and dripping were carefully preserved and analysed with the lean cooked meat of the chop; while in the other case (£) they were excluded: In 100 parts. Water .... a ... 51-6 b 54'0 Nitrogenous matter 27-6 36-6 Fat IS'4 9-4 Mineral matter ... 3-0 I "2 Other substances 1'2 The useful lessons to be drawn from the above analyses will be best studied by a reference to the composition and properties of the several nutrients, as described in the First Part of the present Handbook; it would require too much space to enlarge upon these matters here. Cases 69 & 70. Before giving some analyses of other kinds of meat, it would be well to remind our readers of what was said on p. 148 about the great variation in composition which different animals and parts of animals present. Thus, the following figures must not MEAT AS A FORCE-PRODUCER. i53 be looked upon as representing a series of standards. They have been drawn up from the numerous analyses* (of the carcasses of various animals) which have been carried out by Messrs. Lawes and Gilbert. We quote them from the former "Inventory of the Food Collection." The Composition of i lb. of Beef. Mutton. Pork. Veal. Lamb. Water - 80. oz. gr. . 7 16 . oz. gr. . 6 69 . oz. gr. .IO O . oz. gr. ■ 8 44 oz. gr. Albuminoids - 1 122 . . O 385 . • 0 315 . . I 199 . ■ 0 360 Ossein-like substances 1 62 . .. I 52 . - 0385 . . I 82 . 0 400 Fat - - - 4 340 . . 6 176 . .80. . 2 28l . ■ 5 263 Mineral matter - 0 350 . . 0 245 . . 0 105 . . O 312 . . 0 244 According to Frankland, 1 lb. of the lean of beef, if digested and oxidized in the body, might produce an amount of force equal to 885 tons raised 1 ft. high. The greatest amount of external work which it could enable a man to perform is 177 tons raised 1 ft. high. One pound of lean mutton-chop can produce at the utmost rather less than 2 oz. of the dry nitrogenous substance of muscle or flesh, that is, assuming the analysis by Mene given on p. 152 to* be a fair representation of this article of food. The following further data relate to other meats, &c., as force- producers, the higher figures representing the total amount of force capable of being set free by the digestion and oxidation within the body of those animal foods, and the lower numbers representing the force available for external work—both in tons raised 1 ft. high, or "foot-tons :"— 1 lb. of beef fat I lb. of lean of veal - I lb. of boiled ham - Foot-tons. 5,626 ... 1,125 726 ... 145 1,041 ... 208 * A series of photographs of French breeds of oxen, sheep, and pigs will be found in the Collection; also a series of stuffed and mounted heads of some of the chief breeds of British oxen. A head of the eland, a large kind of antelope, is also shown. This African animal has been successfully bred in England. Its flesh is tender and of excellent flavour. i54 TRIPE AND SWEETBREAD. This seems the proper place to introduce a word or two con- cerning some of the internal parts of animals (or viscera) which are consumed as food. These often require careful cleansing and thorough cooking, and are more likely to be diseased than the muscular flesh. In most cases they are of very close texture, and they do not always contain the same kinds of nutritive nitrogenous matters as are present in ordinary meat. Calves' Liver, according to Payen,s analysis, contains the following proportions of its constituents :— In 100 parts. Water ....... 72-3 Nitrogenous matter 20-1 Fat, &c. 6-1 Mineral matter - - . - - 1-J Here the ratio of flesh-formers to heat-givers, reckoned as starch, is as 1 to 7-ioths—a proportion which shows the pro- priety of the use of fatty or starchy food with liver, as illustrated in the familiar dish of "liver and bacon." Case 70. Tripe is the cleansed paunch or first portion of the ruminant stomach of the ox. The exact nutritive character of tripe is not known. It generally contains much fat. A sample as sold by the butcher, but freed from the lumps of fat present, showed the following composition :— Water Nitrogenous matter Fat - Mineral matter - These numbers show a high percentage of water and a low percentage of mineral matter, due to the cleansing and boiling in water which tripe undergoes before it is sold. Sweet-bread should be the thymus gland of the ox: the pancreas goes under the same name. Among other viscera or in- In ioo parts. In 1 lb. oz. gr. 12 2l6 I 262 79-5 ... IO-O ... IO-O ... I 262 0-5 ... 0 35 POULTRY AND GAME. 155 ternal organs of animals which are eaten are the heart and the kidneys. Both of these organs are of very dense and firm tex- ture and cannot be regarded as of easy digestibility. They are highly nitrogenous articles of food, but the heart generally contains some fat. Case 71. Reference has already been made to the composition of bone. Blood, especially pigs, blood, is sometimes used as food in the form of black-pudding. It requires a considerable admixture of starchy and oily matter to afford a complete nourishment: it contains about 78 per cent. of water, the remainder being chiefly nitrogenous matter with some mineral salts. Case 71. Bullocks, tongues, horses, tongues, rein-deer tongues, and sheeps, tongues are commonly used as food, and are nutritious and digestible. Some of these kinds are dried and imported in that condition: these require long soaking in cold water before being cooked. § 4.—Poultry and Game. One of the chief characteristics of the flesh of fowls, notably those which are wild, is the almost entire absence of fat. When much fat is present the flavour of the meat is often less delicate, and its digestibility, especially when roasted, decidedly difficult. It does not seem that game, even when "high," and therefore to some extent decomposed, is really unwholesome when properly cooked. A very large number of birds furnish food to man, in of^rds^Yal different quarters of the globe. The flesh of those 72°to 77?e Cases birds which feed on grain or other vegetable pro- ducts is less strongly flavoured than that of carnivorous birds. A mere list of names of the most important kinds of poultry and game would not be very useful, in the absence of details con- cerning their relative values as food, and the chemical composition REPTILES. 157 Edible Birds, Nests. Case 77. Edible birds, nests may certainly rank amongst the curiosities of food. They are considered great delicacies in China, where they form part of all ceremonious feasts, being dissolved in soups. They reach China from the Southern Archi- pelago, chiefly from Java, Borneo, Celebes, and the Sulu Islands. It has been estimated that no less than 8,400,000 of these nests are annually imported into Canton. The finest and whitest kind sells for as much as £$ or £6 the lb., but it requires about fifty nests to make up one pound. In reality these singular structures are rather the brackets upon which the birds afterwards build their nests than the nests themselves. The bird—a kind of swift known as the salangan (CoHocalia escuknta\—builds both in marine and inland caverns, first forming, mainly with its saliva, a number- of loops, which it subsequently works up into the shell-shaped support for its nest. The nest itself is made of grass, leaves, and seaweed, but the edible bracket or support consists almost exclusively of the salivary secretion of the bird. It is a mistake to suppose it to be made of seaweed, which the salangan neither eats as food nor uses in the building of these brackets, though the nests are often made of it . The salangan builds and breeds four times in the year. The brackets are removed three times, the best being obtained in July and August.* Reptiles. Case 79. In this country the reptiles used as food are few in number. Their flesh is regarded as a luxury. It is, however, wholesome and digestible. The green turtle of the West Indies, and of some parts of the South American coast, is the best known * Specimens of these nest-brackets, cleaned and in their natural state, and of the salangan swift, are shown in Case 77. 158 FISH. and most highly appreciated of the reptiles used as food. These animals sometimes weigh as much as 700 lb. They are imported alive into this country. Their flesh is the basis of turtle-soup. Sun-dried turtle, cut into convenient pieces for culinary purposes, are now received in this country from the West Indies and other places. They are an excellent substitute for live turtle. The land tortoise, which is common on the Medi- terranean coasts, is eaten by the inhabitants of Italy and the Levant. A small fresh-water turtle, the terapin, is eaten in America, and is imported into this country. A large frog (Sana esculenta) is eaten in many parts of Europe. The hind legs are selected as the best part to be consumed. Various other reptiles are eaten in different countries—the iguana in Guayaquil, the tegu or tequixin in Brazil, the axolotl in Mexico, and the green lizard in Rome. § 5.—Fish, &g. Cases 80 to 87. The kinds of fish commonly available for food in England are numerous. The muscular flesh of the same fish differs in different parts of the animal and in different seasons of the year. Those fish which are least oily and fat are the most wholesome; but their highly nitrogenous character demands the abundant use of starchy foods, in order that a due propor- tion of heat-givers may be consumed along with the flesh- formers they contain. A dry, woolly, or tough texture in the muscular fibre of fish is an indication of indigestibility. Thorough cleansing and thorough cooking of fish is essential to its wholesomeness. Lemon juice is one of the best sauces that can be used with fish: some of the compound sauces in vogue are of very doubtful composition and purity. The least oily fish are whiting. They are the most easily digested, especially when boiled. Flounders, soles, plaice, and several other kinds, are nearly equally available for the invalid. Eels, FISH. 159 salmon, herrings, and even mackerel, are far more oily and less digestible.* The published chemical analyses of fish are very discordant. This arises in great part from the condition of the fish varying at different times of the season. An analysis of a mackerel in good condition gave— Water Nitrogenous matter .... Oil or fat Common salt Phosphates, potash - salts, and other mineral matter .... 3-1 ... o 217 In the nitrogenous matter named above is included a sub- stance known as creatine; it abounds in skate and cod. Cases 80 & 81. We quote (under all necessary reserve) the following figures from the former " Inventory of the Food Collection" :— In 100 parts. In 1 lb. 687 oz. gr. 10 434 13-5 2 70 125 2 O 2'2 O 154 Composition of i LB. OF Salmon. oz. gr. Water- - 12 143 . Mackerel. Sole. oz. gr. oz. gr. Conger-eel. Pike. Herring. oz. gr. oz. gr. oz. gr. .. 10 374 ... 13 374 . .. II 208 .. . 12 28l . .. 12 406 Nitrogenous, matters - f 4J • •• 3 387 - 1 35° • ■• 3 233 •• • 3 23 . I 270 Fat - - 0 301 .. ,. i 56 ... 0 14 . .. 0 57 ... 0 136 . .. O 350 .. .. O 84 •• . O 42 . . O 91 ., I 60 • 0 145 Mineral matter 0 387 .. * Mounted specimens of the common sorts of fish brought to the London markets are shown in Case 82. A painted plaster-cast of a full-grown salmon, a mounted specimen of a male salmon (Case 82a), and a set of earthenware troughs, to illustrate the method of artificially hatching out the ova of salmon and other fish, are exhibited. Specimens of dried fish of various kinds may be seen in Cases 83 to 87. Amongst these is a collection of edible fishes from Victoria, Australia ; and many sorts of dried fish, &c, from the French colonies of St. Pierre, Tahiti, and Cochin-China. These latter specimens include capelins, herrings, cods' tongues, shrimps, prawns, trepangs, &c. Specimens of the Bummeloh fish of the Chinese Seas and Indian Ocean are also shown. These fish, known in Bengal as "Bombay ducks," are of delicate flavour when fresh, but by drying and salting acquire a very strong smell and taste. Diagrams presenting a tabular view of the families and orders of fishes are shown in the collection. *~ i6o OYSTERS. According -to Frankland,s experiments, the following figures represent the force, expressed in foot-tons, which could be liberated by the digestion and oxidation in the body of i lb. of whiting and mackerel: Whiting Mackerel Total work. 49I External work ... 98 1,000 200 The consumption of fish in London is very large; the chief market is Billingsgate. Fish are preserved for subsequent use in several ways—by drying, by smoking, by salting, and by the use of oil. The removal of moisture or the exclusion of air is the chief condition of success. Most kinds of dried and salted fish are rendered more palatable and wholesome by being soaked for some hours in cold water. The fish which are most easily preserved are those of firm texture, or of moderate size, and particularly those which are naturally rich in oil or fat. Herrings, anchovies, pilchards or sardines, and salmon, are familiar examples. The dried bummeloh fish, known in India as "Bombay ducks," are highly esteemed. Caviare, the roe of the sturgeon, is generally con- For specimens . of dried fish, &c, sumed in a decomposed state, and then cannot be considered wholesome. Fresh caviare is a very different article, and does not demand an acquired taste for its appreciation. Case 88. Oysters and other molluscs may be briefly noticed here. Oysters are most digestible when eaten raw, much of the nitro- genous matter they contain being rendered tough and insoluble by heating. Oysters are often improved in flavour and whole- someness by being kept for a day in a shallow dish with some weak brine, a little oatmeal being given to them. Oysters con- tain about 14 per cent. of flesh-formers and 80 of water. Mussels are more frequently found in an unwholesome condition than oysters. BACON AND PRESERVED MEATS. 161 On the continent of Europe there is one kind of snail which is often eaten as food. It is common in some parts of southern France, and is also found rather abundantly in many of the southern parts of England. It is called the Roman or apple snail (Helix pomatia). When properly cleansed and properly cooked it is a nutritious article of food. It can be collected only for a short period during the summer, but then is found in large numbers in some districts in Gloucestershire, Kent, and Surrey. It occurs abundantly on the site of many Roman stations in England, and is believed to have been introduced by the Romans. Cases 89 to 91. Lobsters and crabs are not very easy of digestion. The latter should be cleansed with the greatest care before being eaten. These Crustacea are very coarse feeders, and it is probably for this reason that they so frequently disagree even with healthy persons. Other Crustacea commonly eaten in Great Britain are the fresh-water cray-fish, the shrimp, and the prawn.* § 6.—Bacon and Preserved Meats. By salting, or by the exclusion of air, many animal products used as food may be preserved for a long time free from decom- position. It is not to be supposed that no changes in com- position occur, but the decay to which meat of all kinds is so prone does not take place. In most cases the digestibility of the meat is not improved but rather diminished, at all events by salting, though this is probably not equally true of " tinning," and is not the case when the process of freezing is employed. We will first describe the salting process, as applied to pork, giving this instance as an illustrative example; afterwards we will notice other methods of preserving meat. * Specimens of many different crabs, lobsters, and other Crustacea, aTe shown in Cases 89 to 92. COMPOSITION OF BACON. 163 injury to which bacon is subject arises from the attacks of a small fly, the larvae of which are known as jumpers. For domestic use pork may be cured as follows :—Stir some salt with hot water till no more of the substance is dissolved: this forms the brine or pickling liquor. Then mix, for a pig of mode- rate size, one pound of brown sugar and half-a-pound of nitre; rub this mixture well into the meat, which is then to be put into the pickle, remaining there two days. After this take it out and rub the pieces with salt alone. Return it to the pickle. It will be ready for use, after drying and smoking, in six or eight weeks. It is scarcely necessary to say that bacon varies greatly in compo- sition. It always contains less water and more mineral matter than the pork from which it has been prepared, while the fat in it is more digestible. Highly smoked and dried bacon sometimes retains but 12 or 14 per cent. of moisture; but a fair sample of streaky bacon, such as would be selected for the breakfast table, would be nearly represented, both as to moisture and its other chief constituents, by the following numbers: Case 93. In 1oo parts. In i lb. 02. gt Water 22-3 ... 3 24S Nitrogenous matter 8'1 ... 1 130 Fat 65-2 ... 10 189 Salt 3-8 ... o 256 Phosphates, &c o-6 ... o 42 For one part of flesh-formers in the bacon examined there are nearly 20 parts of heat-givers, reckoned as starch, the 65'2 per cent. of fat being equivalent to nearly 160 parts of starch: and it must be further noted that the whole of the 8-i per cent. of nitrogenous matter shown in the analysis cannot be reckoned as true albuminoids or flesh-forming nutrients, but, being in part, related to gelatin, is of less value. On this account we must reckon the amount of dry muscular substance producible from 1 lb. of bacon as under 1 oz. The unsalted trimmings and offal of a bacon factory are m 2 164 PRESERVED MEATS. utilised in the form of sausages, the minced materials being mixed with bread, fat, and condiments, and then preserved in the previously prepared small intestine of the pig. The surplus fat is melted, strained, and poured into cleaned pig-bladders; it is known as lard Considerable quantities, both of bacon and of lard, are imported into this country from British colonies and from foreign countries. In 1875 the imports of bacon and hams amounted to 131,495 tons; the imports of lard to 26,967 tons; and the imports of salted pork to 11,639 tons- During the first three months of 1876 the imports of bacon and hams showed an increased value of ,£400,000 over the corresponding period of 1875' Preserved Meats. Case 94 and 95. There are several plans of preserving meat and animal food products generally. Simple drying is one of the most effective of these, but the flavour and other qualities of the meat are not improved thereby in most instances ; still this plan is available for some substances, and has long been in use. Drying in wood-smoke has the further advantage of preserving the sub- stance, to some extent, from further change even should it become moist. This effect is due to the creasote or carbolic acid which is present in the smoke. It has even been found that a piece of fresh meat which has been dipped in a watery solution of carbolic acid will dry up without becoming offensive in odour or taste. Salt, sugar, and many substances of a saline nature may be used to preserve meat from decomposition. They act by re- ducing the proportion of water present, and by preventing the development of those lower forms of vegetable and animal life which accompany and aid, if they do not originate, decay. But the most important methods of preserving animal products depend upon the exclusion of the air. This result may be achieved in TINNED MEATS. 165 several ways, which do not appear at first sight to have much in common. In all of them, however, the objects in view are the removal of the air originally present in the food, and the preven- tion of any subsequent entrance of air. To accomplish these ends numerous plans have been devised. For the air may be excluded or removed by a high temperature or by a low one, or by the introduction of a substance like oil or fat, which mechani- cally excludes the air. Of the later method, sardines and pilchards preserved in oil, and then closed or hermetically sealed in tin cases, afford an illustration. Of the former method, the Australian meats are good examples. The meat, freed from bone, is placed in the tins, which are usually surrounded by a boiling solution of chloride of calcium, capable of being heated several degrees above the boiling point of water. The air in the meat is expelled by the heat, and finally by the rush of steam. When, by experience, this expulsion of air is judged to be com- plete, the tins are quickly soldered up and will then keep sound a great length of time. It should be stated that the tins often receive an addition of gravy, or, rather, of jelly, with a little salt, and occasionally some condiment or spice. Other processes for preserving meat have not proved equally available. Such pro- cesses are briefly noted here. The joints to be preserved have been coated with collodion, with solid paraffin, or with a mixture of gelatin and treacle, or gelatin and glycerin. Solutions of the sulphites of lime, magnesia, or soda, which absorb oxygen readily, have been employed. The sulphite of lime in powder, sometimes sold as a "meat preserver," has been successfully used for preventing meat from becoming tainted in hot weather, and in removing any taint which may have been acquired. Powdered charcoal, if freshly burnt, has the same properties. But the pre- viously described method of enclosing meat in sealed vessels— generally of tinned iron, but sometimes of glass—is undoubtedly the most generally applicable of all meat-preserving processes. The same method is used, also, for the preservation of nearly 166 AUSTRALIAN MEATS. every kind of moist vegetable and animal products used as food, but prone to decay under ordinary conditions. The tinned Australian meats are gradually becoming more appreciated in England. They are moderate in price, agreeable in flavour, and perfectly wholesome. They generally have one defect, it is true, that of having been over-cooked. But during the last year or two several improvements have been devised in the process of tinning meats, by which the considerable heat and length of time necessary to secure complete expulsion of the air, before the tins in which the meat is contained can be sealed up by soldering, have been reduced. It has been found that a little sulphite of soda enclosed in the tins may be used to absorb the last traces of oxygen—that constituent of the air which causes decay. And even gases, such as carbonic acid, carbonic oxide, and sulphurous acid have been introduced into the vessels containing preserved foods, for the same purpose. Then, too, methods of injecting antiseptic gases or solutions into the carcasses of animals used for food have been experimented with. Further progress will doubtless be made during the next few years in these directions; much, for instance, may be expected from the application of cold and of condensed gases in the preservation of provisions. We also regard the processes of drying and smoking as worthy of more extended use in connection with the preservation of butchers' meat. From Australia we already receive smoked and dried legs of mutton of excellent quality. Cases 94 and 95. The importation of tinned Australian meats has assumed very considerable proportions since its origination ten years ago. During the last few years the annual value of these Australian tinned meats has often exceeded ^500,000 sterling. It may be well to state that the prejudice against these tinned meats has been partly of the usual unreasonable sort, which revolts against all novelties in food; and has partly arisen from ignorance as to suitable modes of cooking these meats 168 USES OF FOOD-ADJUNCTS. PART IV.-OF FOOD-ADJUNCTS. It is impossible to draw a sharp line of distinction, between true nutrients and food-adjuncts. There is scarcely a single article of food which does not possess some constituents which give it flavour, perfume, or colour, but which yet cannot be considered as doing any actual work in the body. But these adjuncts, in the forms of flavouring and colouring matters, &c., make our food agreeable, stimulate a flagging appetite, aid indirectly in the digestion of the nutrients, and help to render palatable food which would otherwise be wasted. More than this: some of the food-adjuncts actually furnish—along with thei* characteristic flavouring, stimulating, or narcotic constituents—real nutrients. Cocoa and beer are examples in point. And it has been thought that the active principles of certain food-adjuncts have some power of economising the true nutrients by arresting the rapid changes of tissue, &c., which go on in the body. In general terms we may affirm, that if injurious or even dangerous con- sequences may follow upon the excessive use of the true nutrients of the body, much more will this be the case with the food- adjuncts. The order in which we shall consider the several groups of food-adjuncts has been already indicated (p. 9). The first group contains alcohol as its most characteristic ingredient. ALCOHOLIC LIQUORS. 169 § 1.—Beer, Wine, and Spirits. The food-adjunct which is present in all fermented liquors, and in the different kinds of distilled spirits prepared therefrom, is a liquid known as alcohol and as spirits of wine. This liquid burns readily when a flame is applied to it, but it is very doubtful whether it is ever completely burnt or oxydised in the human body. Contrary to the general impression, it now appears that alcohol in any form lowers the temperature of the body. To many constitutions it is decidedly injurious, even when consumed in very moderate quantities and in the weakest or most dilute liquors. Its use throughout the day is nearly always fraught with danger. It is probable that it is best taken, not as a stimulant before work, but as a restorative after work, and as an accompaniment to the substantial meal of the day. Much, too, depends upon the form in which the alcohol is taken. Light wines, perfectly natural and not fortified with spirit, and pure beer or ale, are probably the most desirable liquors for general use. The worst kinds are distilled spirits, not only because of their strength, but because of the absence of those other con- stituents which modify the effect of alcohol in other beverages. But there is another bad quality in most spirits—that is the presence of a liquid called fusel oil. The exact physiological action on the human organism of fusel oil is not ascertained, but there is good reason to believe this liquid (in reality itself a kind of alcohol) to be more active than ordinary alcohol. We shall recur to this subject in the paragraph on distilled spirits. Here, however, a few further words about ordinary alcohol may not be out of place. The term "absolute alcohol" is used to designate pure spirits of wine wholly unmixed with water. It is chemically pure alcohol, the hydrate of ethyl, a liquid boiling at 1730 Fah., and having the specific gravity 794 (water being 1000). Proof spirit is a mixture containing A9% per cent. of its weight of absolute alcohol: its specific gravity is 920. 170. MALT AND MALTING. Beer. French, Biere. German, Bier. Italian, Birra. Case 96. The most commonly used of all fermented liquors in England is beer, under which term we include ale and porter. These liquors are prepared from malted grain by simple fer- mentation, without concentration, dilution, or distillation of the fermented liquor. The three materials employed in the manufacture of beer are malt, hops, and water. The malt is made of sprouted or germinated grain, usually barley or rye. To prepare malt the grain is first placed in the "cistern," where it remains 50 hours, absorbing a large quantity of water and swelling considerably. It is then shifted into what is called the "couch," where, according to excise regulations, it remains 20 hours, and where the duty is taken by gauge. After this it is removed to the "floors," where the process of growth soon makes itself evident by the appearance of the slender rootlet of the seed. Barley in this stage of its conversion into malt is shown in specimen 3; while 4 shows the grain when it is six days old, the sprout, or acrospire, as it is called, being now much longer. The next specimen (No. 5) is of the grain when 10 days old, and No. 6 shows the grain when the sprouting has gone on to the full extent desired. Most maltsters and brewers dry the grain when it is from 10 to 12 days old, but occasionally 14 days elapse before the process of malting is considered sufficiently complete. These variations depend partly upon the quality of grain em- ployed, partly upon the temperature during malting, and partly upon the special purpose for which the malt is intended. When the germinated grain is considered sufficiently grown, further sprouting is stopped by drying it in the malt-kiln. The heat used causes other changes, and is different according to the kind of beer for which the malt is to be used. Some idea of the tem- peratures may be gathered from this list:—No. 7, pale malt, for the palest ales, at about i000 Fah. No. 8, amber malt, for other ales, at about 1200 Fah. No. 9, brown malt, for porter, at about BREWING. *73 isinglass dissolved in tartaric acid, in sour beer, or in weak sulphuric acid. There are many other fining materials which may be used. The finished beer holds in solution a large number of sub- stances, but the quantities of these substances present are not large—this fermented liquor always containing between 80 and 90 per cent. of water. The following is a list of the chief com- pounds known to occur in beer:— 1. Alcohol, or spirits of wine, from 8 to 3 per cent 2. Dextrin, about 4-5 per cent. 3. Albuminoids, about 0-5 per cent. 4. Sugar, about 0'5 per cent. 5. Acetic, Lactic, and Succinic Acids, about o'3 per cent. 6. Carbonic Acid Gas, about 0-15 per cent 7. Mineral Matter, about 0'3 per cent. In the following analyses only some of the above constituents are separately entered, the items 2, 3, and 4 above being, for instance, set down as "extractive matter," a term which includes also several substances not named above (glycerine, caramel, hop-extract, &c.). An imperial pint of the beers named contains— Beers. Water. Alcohol. Acetic acid. Extractive matter. Mineral matter. oz. gr. 18 342 18 412 18 409 oz. gr. gr. 22 16 oz. gr. gr- 22 18 10 3° London Stout London Porter Pale Ale Strong Ale - 1 74 1 .10 1 25 1 12 17 21 1 3 0 372 17 399 2 18 2 42 A few words may not be out of place here as to the intro- duction of other materials (besides those already named) into beer. But it should be at once stated that many tf the substances f~ 174 WINE. supposed to be used for the purpose of adulterating beer and malt liquors are rarely so employed, and that some of these substances have never been so used. Thus, the rumour that strychnine (from the seeds of Strychnos nux-vomicd) had been exten- sively used to give bitterness to beer was entirely devoid of foun- dation. There is also reason to think that the employment of "Cocculus Indicus "—the fruits of Anamirta Cocculus—in brewing has been very limited and exceptional: other bitter vegetable products have however been detected in some samples of ale. Caramel, or burnt sugar, liquorice, and salts of iron have been found in porter. A very common adulteration is salt—the object of this addition being not so much to develop the flavour and preserve the liquor, as to produce a craving for more drink in the frequenters of the beer-shop. Much artificial sugar (glucose) is also used in brewing, for the purpose of strengthening the wort. The use of gypsum, of which we have before spoken, can hardly be regarded as an adulteration. Beer which is sour or hard, or that which is thick and muddy, is not wholesome. The decided sourness of some beers is due to the alteration of a good deal of the spirit, which by ex- posure to air acquires oxygen, becoming changed into vinegar or acetic acid. The cloudiness of beer is often due to a second fermentation. Wink. French, Vin. German, Wan. Italian, Vino. When the sugary juice of any fruit is left to itself for a time, at a moderately warm temperature, the change known as fermen- tation occurs. This fermentation is generally brought about by the growth of a low form of vegetable life, an organised ferment. It consists of a splitting up of the sugar present in the liquid (or at least of a large part of it) into alcohol, which remains in the liquid, and carbonic acid gas, which escapes more or less com- pletely. CONSTITUENTS' OF WINE. 175 Case 96. Although the fermented juice of all fruits may be regarded as wine, yet the term is generally limited to the al- coholic liquor prepared from the grape. But we have in England at least two familiar native wines—perry, or pear wine, and cider, or apple wine. Other so-called British wines are usually made-up or compound liquors, into which a large quantity of cane or beet sugar has been introduced. They cannot be regarded as true wines, nor are they generally wholesome. By a reference to the analysis of grapes (p. 118) it will be seen that the chief ingredient in their juice is glucose, a kind of sugar. There is also some albuminoid matter and a little tartaric acid, chiefly in combination with potash; other minor ingredients also exist in grape-juice. The seeds of the grape contain the astringent substance, tannin, with some bitter principles, while in the skins not only does colouring matter exist, but also some flavouring matters and tannin. From these facts it will be clearly seen that very different qualities of wine may be made from the same quality of grape, according to the method of operating upon the fruit. The colour, the bouquet or volatile flavour, the astringency, &c., of a wine may thus be varied according to the admission or exclusion of the characteristic ingredients of the skins and stones of the grapes. Case 97. The main difference between grape juice and grape wine is the substitution of the sugar in the former by the alcohol which is characteristic of the latter. But other changes occur in the fermentation and ripening of wines. Much of the acid tartrate of potash is deposited from the liquid on being kept, this deposit being called argol. Argol consists chiefly of the above-named tartrate, but with it a little colouring matter and some tartrate of lime are always found. In the stronger but natural white wines small floating crystals of cream of tartar often occur; they are nearly pure acid tartrate of potash. A small quantity of free acetic acid is found in wines. When they become sour it is this acid to which the sourness is due; it is formed by the oxidation of some FOREIGN AND ENGLISH WINES. 177 natural strength, while the average of all Spanish wines does not show much over 28 per cent. of proof spirit—rather less than 14 per cent. of absolute alcohol. Case 97. The following table shows the quantities of alcohol, of fixed acids—calculated as tartaric acid—of acetic acid, of sugar, of ethers, and of mineral matter or ash, contained in fair average samples of eight different kinds of wines commonly consumed in Europe. One imperial pint of each of the following wines contains about— Name of Wine. Alcohol (absolute). Tartaric and other fixed acids. Acetic acid. Sugar. Ethers. Mineral matter. oz. gr. gr. gr- oz. gr. gr- gr- Hock I 219 39 18 none 4 16 Claret I 306 3i 18 0 9 6 18 Champagne I 343 20 IO 1 120 5 20 Burgundy - 2 18 24 17 0 10 6 18 Carlowitz - 2 35 36 19 none 5 16 Sherry 3 147 24 12 0 236 4 38 Madeira 3 218 26 18 0 175 5 33 Port - -" - 3 218 23 12 0 359 6 20 The different wines made in this country from rhubarb stalks, gooseberries, currants, cowslips, elderberries, oranges, &c., con- tain oxalic, malic, and other acids, besides the tartaric acid which is the chief acid of the grape. Now these acids are not thrown out of the liquor after fermentation, as is the case to a great extent with the wine from grapes. Thus sugar has to be added to mask the acidity of these liquors, and in consequence they are not so wholesome as the natural imported wines. But it must not be supposed that grapes are entirely free from all acids save tartaric, or that the analyses above given represent every constituent of the wines we have included in the table.* * Specimens of grapes, &c, will be found in Case 58. A model vineyard is labelled 101. Samples of British wines are shown in Case 98. N I78 DISTILLED SPIRITS. The ethers of wine previously alluded to include a number of compounds not yet completely analysed or understood. Some of them, however, have been examined pretty fully, and even exactly imitated by chemical means. CEnanthate, butyrate, and acetate of ethyl are the names given to some of the best known of these ethers. These ethers enter into the composition of the artificial "oil of cognac" and various flavouring essences. Cider, the fermented juice of apples, contains from 2% to 4^ per cent. of absolute alcohol, together with some malic acid, gum, mineral matter, &c. The quantity of sugar present varies with the less or more complete fermentation of the apple-juice. Perry, made from pears, closely resembles cider in flavour and composition. Distilled Spirits. When any kind of fermented liquor is warmed, the vapour which first comes off contains much of the spirit or alcohol present. If the vapour be collected and cooled it assumes the form of a liquid, which originally received the name of spirits of wine. The operation is known as distillation, and the product is called distilled spirits. As the heat is continued the distilled liquid becomes weaker and weaker, containing more water and less alcohol. The cause of the differences in flavour between distilled spirits from different sources lies not in the alcohol, but in the traces of ethers or essential oils which accompany this alcohol—which are volatile, like alcohol, and which are easily dissolved by it. The flavours of distilled spirits originate in the substances which by their fermentation have given rise to the alcoholic liquors which have been distilled. But it is usual, in many cases, to add flavouring matters of many kinds to distilled spirits. Indeed, from the same batch of spirits obtained by the distillation of a fermented solution of grape sugar or malt sugar, either gin, or whisky, or brandy may be prepared. The spirit i82 LIQUEURS. flavouring material of rum is butyric ether, but this spirit some- times receives in addition the flavour of the pineapple. Case 99. Besides gin, brandy, whisky, and rum, there are many kinds of spirits from sources other than those already named, and possessed of different flavours, artificial or natural. Amongst these we may name the following, premising that all the products are obtained by the distillation of a fermented solution of sugar—that sugar being naturally present in the original fruit, root, &c., or else produced by a change of starch into sugar. Distilled spirits are obtained from oranges, cashew-nuts, apricots, Jerusalem artichokes, sugar-millet, potatoes, flowering branch and sap of many palms (arrack), cider, cider lees, maize, honey, refuse of starch manufacture, &c. &c. A Japanese spirit, called "saki," is distilled from rice. The peculiar and often disagreeable odour and taste of dis- tilled spirits may be removed by careful and repeated distillation, and by very thorough filtration through animal charcoal. Some chemical substances are also found to be useful in aiding the separation of the fusel oil and other substances upon which the odour and flavour of different distilled spirits depend.* Liqueurs. Case 99. When a considerable quantity of sugar is added to a flavoured spirit, a cordial or liqueur is the product. The flavour- ing materials used ih liqueurs are named in the next section of the present part of this volume: they are very numerous, and include natural products, as fruits, seeds, bark, and roots, as well as the essential oils and separated aromatic principles of these parts of plants. Orange bitters contain the essential oil of orange- peel and the bitter substance which accompanies it . Noyau is, * In Case 100 there are numerous specimens of distilled spirits or alcohol from new or unusual sources. They have been rendered potable by filtration through charcoal, &c. CONSUMPTION OF ALCOHOL. 183 flavoured with the essential oil of bitter almonds, which is iden- tical with that distilled from peach kernels, laurel leaves, &c. Chartreuse contains a peculiar kind of turpentine, with the essen- tial oil of angelica. The names of other liqueurs sufficiently indicate the nature of the flavouring substances to which their taste and some other qualities are due. Absinthe is wormwood, and gives its name to a bitter liqueur much consumed in France. Tea, coffee, cocoa, and vanilla are also employed in the pre- paration of liqueurs or flavoured spirits. Some notion of the amount of spirits annually consumed in Great Britain may be gained from the following figures, which represent the total Customs and Excise duties on spirits paid in the year ending 31st March, 1876 :— England • ^13,206,64? Scotland- ....... 4,04.1,419 Ireland .....--- 3,328,752 Total - £20,576,612 The total value of these distilled spirits amounted 10^43,067,022. If to this figure we add ^72,785,921 as the cost of the malt liquor consumed in one year, ^13,112,029 for the foreign wines, and ^1,000,000 for other alcoholic liquors, we arrive at a grand total of ^130,000,000 or more as the annual value of the alco- holic beverages made in or imported into the United Kingdom. It is estimated that the above annual quantity of distilled spirits contains 21,000,000 gallons of absolute alcohol, the total quan- tity in all the beverages being at least 80,000,000 gallons. The number of gallons of spirits paying duty in the year 1875 was as follows:— Gallons. British spirits ....... 30,106,107 Colonial spirits ...... 5,361,486 Foreign spirits - • - - - - 6,421,164 Total - 41,886,757 184 MUSTARD. The duty payable on imported spirits is ioj. $d. per gallon. Most of the rum imported came from British Guiana and the British West Indies. From France 3,250,000 gallons of brandy were received, and from Holland a small quantity of Geneva. § 2.—Condiments, Spices, and Flavourers. The taste of many vegetable products is so definite and so strong that they cannot be used as substantive articles of diet These fruits and seeds, &c., are, however, very useful as means of imparting agreeable flavours to the simpler food materials, which thus become not only more palatable but more wholesome. Still, the condiments, spices, and flavourers must be used with moderation, or their action on the processes of digestion and assimilation may become injurious. The chief active and efficient ingredients of this group of food-adjuncts are volatile—that is, they may generally be dissi- pated by a moderate heat. Most of them are known as essential oils, but some are solid crystalline bodies or resinous matters. We shall here first describe the chief condiments, then the spices, and afterwards the group to which the name of flavourers has been given. Mustard. French, Moutarde. German, Senf. Italian, Mostarda. Case 102. Black Mustard is the seed of Brassica nigra, a plant found wild in most parts of Europe. It is cultivated in Elsass, Bohemia, Italy, Holland, and England. It flourishes in the rich alluvial soils of Lincolnshire and Yorkshire. It was in common use in the Middle Ages as a condiment. Black mustard seeds are but one-fifth the size of white mustard seeds: they contain one-third of their weight of a bland fixed oil, while the pungent essential oil is not produced till the ground seeds are wetted. This pungent oil contains both nitrogen and sulphur. The best flour of mustard contains nothing but black and white mustard seeds: PEPPER. 185 some manufacturers, however, produce an inferior material con- taining flour, turmeric, and capsicum. The seeds of another kind of mustard (Brassica juncea) are largely substituted for the true black mustard; no less than 790 tons of this kind having been imported from British India into the United Kingdom in 1872. White Mustard, the seeds of Brassica alba, does not yield a pungent oil. Its cultivation is extending in England, as in Essex and Cambridgeshire. Pepper. French, Poivre. German, Pfeffer. Italian, Pepe. Cass 102. Pepper consists of the fruits (twenty to thirty of which grow on one flower-stalk) of Piper nigrum, a perennial climbing' plant, a native of Travancore and Malabar, but introduced into Sumatra, Java, Siam, West Indies, &c. Pepper owes its pungency to about 2 per cent. of an essential oil: it contains also 2^ per cent. of piperin. White Pepper is prepared from the above-named fruits when ripe by removing the dark pericarp or covering; it thus becomes less pungent. Long Pepper consists of the unripe spike or fruit produced by two other species of Piper, namely: P. longum, a native of Malabar; and P. officinarum, a native of the Indian Archipelago. Cayenne Pepper is prepared from the pods of one or more kinds of Capsicum. The small pods are called chillies, and are produced by C. fastigiatum, a plant which is wild in South India, and cultivated in tropical Africa and America. Chillies have been termed Spanish pepper, red pepper, and pod pepper. Another species of capsicum (C. annuum) yields the larger pods, generally called "capsicums" (the poivrons of the French); of these several varieties exist. This plant was grown in England by Gerarde in 1597: our supplies are derived chiefly from Zanzibar, Natal, &c. The capsicum belongs to the Solanacea, the Order which includes the potato, the tomato, and tobacco. 186 FENNEL. Horse-radish. French, Raifort. German, Meer Rettig. Italian, Rafano. Horse-radish is the root of a common European perennial plant (Cochlearia Armoracid); it has been used as a condiment in England from the 17 th century. It yields a pungent essential oil, which seems to be the same as that from black mustard. The poisonous roots of aconite, Aconitum Napellus, sometimes called monk's-hood or wolf s-bane, have been mistaken for those of horse-radish.* Parsley. French, Percil. German, Peirosilie. Italian, Prezzamolo. , Parsley is Apium Petroselinum, a native umbellifer of Sardinia; the leaves of which are used not only as a garnish, but are eaten. fresh or dried as a flavourer. Mint. French, Menthe. German, Miinze. Italian, Menta. Mint or Spearmint is Mentha viridis, a pleasant aromatic labiate herb, used in seasoning and for boiling with green peas. Thyme. French, Thym. German, Thimian. Italian, Timo. Thyme is Thymus vulgaris, a small labiate shrub of South Europe, not a native of England. Its odour and taste are due to an essential oil known in trade as origanum oil. Wild English thyme (Th. Serpyllum) is a different plant. Fennel is an umbelliferous plant, Fxniculum vulgare, found wild in the countries bordering on the Mediterranean: it has a perennial root stalk, while the Indian plant is an annual. The fruits of fennel (commonly called seeds), as well as the leaves, contain a peculiar aromatic essential oil, which is also found in * Compare the specimens of the roots of these two plants as shown in the collection. CONDIMENTS. 187 anise-seeds. Chopped fennel leaves are used in the melted butter eaten with mackerel: the fruits give flavour to certain cordials. Marjoram (Origanum vulgare), Sweet Marjoram (O. Ma- jorand), Sweet Basil (Ocymum basilicum), and Sage (Salvia officinalis), are all labiate plants, and are known as pot-herbs. Their aromatic leaves are used either fresh or dried for seasoning food. Cumin is an umbelliferous plant (Cuminum Cyminuni) which has been known from very early times. Its fruits contain an essential oil of very strong odour and taste: they are used in the preparation of some spirits and cordials, and form a constituent of curry-powder. Dutch cheese is sometimes flavoured with cumin. Turmeric is the root-stock of Curcuma longa. It is used as a yellow dye as well as a condiment: it is one of the chief ingre- dients of curry-powder. Our supplies come mainly from Bengal and Pegu—the Cochin turmeric is from another species of Cur- cuma. The odour of turmeric is due to an essential oil, present to the extent of 1 per cent. Curcumin is the yellow colouring matter. Chervil (Anthriscus Cerefolium) is an umbelliferous plant, the young leaves of which are used in France for flavouring soups and salads. Dill is an umbelliferous plant (Anethum graveolens) resembling fennel. Its fruits are aromatic, but it is little used for culinary purposes in Europe. Anise, or Pimpinella Anisum, is a native of Asia Minor, Egypt, &c.: it is cultivated in many parts of South Europe. The fruits contain about 2 per cent. of an essential oil, which is used in flavouring cordials. Capers are the flower-buds, and sometimes the unripe fruits of Capparis spinosa, a wall plant of South Europe. Our supplies are chiefly from Italy and France. Capers are prepared and pre- served by pickling them in vinegar. A common substitute for 188 GINGER. them is found in the unripe fruits of the garden nasturtium (Tropaolum majus): other substitutes are also in use on the Continent. Garlic is a native of Southern Europe and is closely related to the onion, but has a much stronger taste. Its bulb consists of ten or twelve parts called "cloves." It is Allium sativum. It is used in sauces. Shallot, or Eschalote (Allium ascolonicum), is a native of Palestine. Its cloves are milder than those of onions: it is used in pickles, salads, and seasoning, and to flavour vinegar. Chives (Allium Schanoprasuni) are a native of Britain. They form a favourite addition to soups in Scotland. Tarragon is Artemisia Dracunculus, one of the Composites. It is closely related to the well-known aromatic plants, common wormwood and southernwood; but, unlike them, its leaves are undivided. It is a native of Siberia, but is cultivated to some extent in France as an ingredient in salads and pickles, and for flavouring vinegar. Savory is of two kinds: summer savory is Satureja hortensis, a most aromatic annual plant, a native of Southern Europe; the other is an evergreen, S. montana. They are used for sauces and seasoning, and admit of being dried. Spices. Spices are usually added to articles of food containing sugar, while condiments are eaten with meat, and generally with any foods which contain common salt. But it is impossible to draw any very distinct line between condiments and spices. Amongst the latter we may include— Case 103. Ginger is the rhizome or root-stock of Zingiber officinale, a reed-like plant now grown in most hot countries: it has been long known and esteemed. Most of our ginger comes from the East and West Indies, and has been scraped. Its odour is due to an essential oil, its hot taste to a peculiar resin. i9o OIL OF LEMON. Caraway, or Carum Carvi, is a biennial umbelliferous plant something like a carrot. It is cultivated to some extent in Kent and Sussex; much is imported from Holland. An acre yields from four to eight hundredweight of the fruits. They contain an essential oil, and are used to flavour cakes, confectionery, biscuits, and cordials. Peppermint is a labiate plant (Mentha Piperita). It is grown in Surrey and Cambridgeshire, and is common, as a wild plant, in many parts of England. The whole plant, especially just before flowering, is rich in an essential oil of aromatic and even burning taste, which is used to flavour sweetmeats and cordials. Coriander (Coriandrum sativum) is an umbelliferous plant of the south of Europe, and is cultivated largely in France. The fruits of this plant contain a small quantity of essential oil: they are used in flavouring cordials. Angelica (Archangelica officinalis) is an umbelliferous plant common in most parts of Europe. Its roots, though of somewhat medicinal taste, are used as food in Norway and Lapland; the stems, boiled in sirup, yield a pleasant sweetmeat; the fruits are used in flavouring some cordials, as Chartreuse. Flavourers. Some artificial and some natural products of strong taste and smell are included in this group of flavourers. In many instances flavourers are prepared by the distillation of seeds, fruits, &c., when the fragrant essential oil comes over and is condensed. Such essential oils dissolved in spirit of wine constitute the extracts or flavouring essences so much used in cookery. But the compound ethers, many of which may be prepared artificially, are now used for similar purposes. The following flavourers are in common use :— Case 103.. i. Essential Oil of Lemon, and of other fruits of the ^enus Citrus, as the orange and the citron. These oils occur in e rind of the fruits, whence they may be removed not only by stillation but by pressure. The fresh peel of these fruits is used VANILLA. 191 for flavouring, but it may be preserved by careful drying. It is also eaten after having been boiled in sirup as candied peel, and in several other forms. Case 104. 2. Oil of Bitter Almonds is obtained—by means of maceration in water, and subsequent distillation—from the bitter almond, a variety of Amygdalus communis. The same essential oil may be got from peach and plum kernels and from laurel leaves. The crude oil, as obtained by distillation, always contains prussic acid in considerable quantity. This most poisonous substance ought always to be removed from the bitter-almond flavouring used in cookery. No preparation of bitter almonds, no essence of " ratafia" or peach-kernels, should be employed in the kitchen unless it is guaranteed to be free from prussic acid. Cakes, custards, and blancmange are flavoured with oil of bitter almonds. The odour and taste of this oil are approached in two artificial products—nitrobenzol and benzonitril. Nitrobenzol, which is incorrectly termed artificial oil of bitter almonds, and sometimes essence of mirbane, is obtained by acting upon benzol (a liquid constituent of coal-tar) with nitric acid. It is poisonous, and has a much less agreeable odour and taste than the true oil. Benzo- nitril is obtained by the distillation of hippuric acid, a substance contained in the urine of horses and oxen. Case 104. 3. Vanilla.—The flavourer known under this name consists of the fruits of an orchid belonging to the genus Vanilla. The most highly-prized sort is obtained from V. planifolia, a plant indigenous to hot regions of Eastern Mexico. It was brought to Europe by the Spaniards.* Other species of vanilla are also used, but are thought to be of inferior quality. The pods of the various kinds of vanilla owe their rich and agreeable aroma to the presence of a white crystalline substance called vanillin. This substance is now made artificially from another natural product— coniferin, which is contained in the sapwood of pines. The * Specimens of vanilla from the French colonies of Reunion (introduced there in 1817), Guadaloupe, and Guiana, are placed in Case 104. i92 SAFFRON. artificial vanillin is not a mere imitation of the natural substance, but is absolutely identical with it . Vanilla is used to flavour cocoa, chocolate, ices, biscuits, creams, and even coffee and tea. Case 104. 4. Artificial Fruit Essences.—Although there are few- cases in which the exact nature of the delicate flavours of fruit has been ascertained, yet there can be little doubt that the dis- covery has been made in some instances. Even were this not so, still there are now known many artificial products, chiefly the so-called compound ethers, which resemble very closely indeed in taste and smell the natural flavours of certain fruits. One of the most extensively used of all these is the acetate of amyl, a com- pound ether which may be regarded as derived from vinegar and potato oil by the removal of the elements of water. The so-called essence of Jargonelle pears is a spirituous solution of the acetate of amyl: it is employed in flavouring confectionery, especially pear-drops. , Unfortunately it is used too freely, and is seldom sufficiently pure for this purpose. Other compound ethers impart the flavour of other fruits to articles of confectionery, liqueurs, and foods. Apple oil is chiefly valerate of amyl, pineapple oil is butyrate of ethyl and butyrate of propyl, and grape or cognac oil is a mixture of several compound artificial ethers. Many other flavourers of similar character have been artificially prepared: they are much used by the makers of cheap confectionery. There are some natural products used as spices, condiments, or flavourers, which we have not described; indeed, a volume would be required for the adequate treatment of this subject, for the details connected with these products are very numerous. Take one example. Saffron has long been used for colouring and flavouring confectionery, fancy biscuits, &c. The plant which yields it, the Crocus sativus, was grown in the reign of Edward III. The part used consists of the stigmas only of the flower, and the colouring substance they contain is so intense that one grain of the commercial saffron will colour yellow ten gallons of water. Our supplies of saffron now come chiefly from Spain and France, VINEGAR AND ACIDS. 193 but the plant was once largely grown in England between Saffron Walden and Cambridge. To give similar details as to other flavourers would obviously occupy an amount of space much greater than the importance of the subject warrants: we cannot therefore further dwell upon these numerous minor flavourers. But we may name in passing that sauces should be included here, for they usually contain mixtures of several condiments dissolved in weak vinegar and other liquids, and that there are some materials of animal origin used in part for the same purposes. Case 94. Of these latter the extract of meat invented by Liebig is the most important. It contains nitrogenous matters, such as creatine, with large quantities of potash salts—in fact, all the constituents of flesh which can be dissolved by hot water. Still, it is a stimulant and flavourer chiefly, and cannot be regarded as a substantive food. § 3.—Vinegar, Pickles, and Acids. Case 108. There are several acids in most vegetable products. They exist partly in the form of salts, and partly in the free state. The most common and most important vegetable acids are these four: Citric Acid, Tartaric Acid, Malic Acid, and Oxalic Acid. To these must be added a fifth acid, the Acetic; which, however, is mainly produced artificially by the change or oxida- tion of alcohol or even of sugar, but which occurs also to a small extent in some fruits, especially when they are over-ripe or decaying. All the acids probably act in the processes of digestion and nutrition in much the same way. They exert a solvent action upon many of the nutrients, but their own nutritive power is very small, for they cannot be consumed in sufficient quantity to give 0 VINEGAR. 195 or chillies. Four kinds or varieties of vinegar are commonly used in Europe. These are—1, Malt Vinegar; 2, Wine Vinegar; 3, Wood Vinegar; 4, Vinegar from starch, sugar, &c. The acid in all of these products is identical, but there are evident dif- ferences in flavour and odour between the different sorts. It is usual, however, by the addition of colouring matter and flavouring essences, to render the detection of the sources of the inferior vinegars very difficult. All the varieties of vinegar, save that obtained by means of the destructive distillation of wood, are formed by the oxidation of alcohol. This compound, however formed, whether by the direct fermentation of sugar or from starchy materials, may be readily oxidized, gaining one additional proportion of oxygen and losing two proportions of hydrogen. The oxidation of weak alcohol into acetic acid may be accom- plished by simple exposure of the liquid to warm air, but the change is usually accompanied and greatly aided by the presence of a vegetable organism such as yeast and the so-called vinegar- plant. Good vinegar contains 5 per cent. of real or glacial acetic acid. Sulphuric acid is sometimes found in it to a larger extent than allowed by law, which is 1 part in 1,000. A solution of chloride of barium produces a more or less dense white precipitate only in vinegar containing sulphuric acid. Case 108. Vinegar is extensively used not only as a condiment in sauces and salads, but for the preparation of a great variety of pickles. The vegetables thus preserved in vinegar include the greater number of those which' we have described in the second part of this volume. Among them we may name unripe walnuts, onions, cauliflowers, gherkins, French beans, red cabbage, capsi- cums, samphire, mushrooms, and small unripe maize-cobs. Care should be taken that pickles are free from copper, a poisonous metal which sometimes finds its way into the vinegar through the solvent action of that acid upon the vessels used in preparing pickles. r o 2 196 TEA. § 4.—Tea, Coffee, and Cocoa. The group of food-adjuncts which we are now about to study is distinguished from all the preceding groups by the presence of a peculiar class of active principles called alkaloids. These con- tain the element nitrogen, which is absent from nearly all the essential oils, from all the kinds of alcohol, and from all the acids which occur in articles of food. Many of these alkaloids act powerfully on the nervous system, generally as sedatives and narcotics. Some of them are not only medicinal, but, even in small doses, actually poisonous. But the action of tea, coffee, and of many other food-adjuncts which owe their properties mainly to the presence of certain alkaloids, is often greatly modified by the other constituents of these food-adjuncts. Tea, for instance, •contains a fragrant essential oil which is stimulating; while the presence of tannin, an astringent substance, further modifies the general result produced by the theine contained in an infusion of tea.* We will first examine into the chemistry of the ordinary beverages—tea, coffee, cocoa, &c., which closely resemble one another in the peculiarity of their active alkaloids; afterwards a few notes on tobacco and opium shall be given. Tea. French, TM. German, Thee. Italian, Ti. (Thea sinensis!) Cases 109 to 113. The plant which yields the tea of commerce is a native of Bengal: it is a shrub nearly allied to the camellia. It has been long grown in China, and may indeed be indigenous to parts of that empire. Our supplies come mainly from China, but a good deal of tea is grown in British India and in Japan. * A fine specimen of theine may be seen in the collection. PARAGUAY TEA. 201 The chief forms of prepared cocoa are— Case n6. Soluble Cocoa. Mixtures of ground cocoa, with starch, &c., are called soluble cocoa. With boiling water a thick mucilage is produced, in which the finely-ground cocoa remains suspended—it does not dissolve. Chocolate is cocoa ground up with sugar and flavoured with vanilla, sometimes with-bitter almonds as well, or with cinnamon and other spices; it generally contains some starch or flour. Flake and Rock Cocoa are made from the whole seed, nib and husk being ground together to a paste. Pressed Cocoa (such as Van Houten,s) is prepared from cocoa- nibs—a small proportion of the cocoa-butter having been pre- viously expressed so as to leave about 33 per cent. Mate, or Paraguay Tea. (Ilex Paraguayensis.) Case 113. In Paraguay, North Corrientes, Chaco, and South Brazil, the leaves of a small tree are used just in the same way that tea is employed in China, India, and Japan. The infusion of these leaves contains tannin, an aromatic oil, and some theine. Indeed, it is a singular and most instructive fact that the chief characteristic constituent of tea, coffee, mate-, guarana-bread, and the African kola nuts, is identical—the alkaloid theine or caffeine. Even cocoa contains a very nearly-related substance—theobro- mine. Naturally, all these plants have come into general use amongst the inhabitants of the countries where they flourish; and now it is ascertained that their chief physiological properties depend upon the presence of a substance which is identical in five of them, and closely allied in the sixth. Mate* is prepared by drying, and then gently roasting the leaves, still attached to their stems and branches: the whole tree being often cut down for this purpose. When the drying and 202 GUARANA-BREAD. roasting have rendered the leaf brittle, and developed the aromatic oil which gives the peculiar flavour and odour to mate*, then the branches are removed to large rough mortars, which are merely pits dug in the ground, where it is beaten and bruised till the leaves are reduced to fragments. The mate, after sorting, is next placed in fresh bullock-skins, well rammed, and placed in the sun to dry. The composition of mate is somewhat variable. Several sorts are known in the South American markets: caa-cuys, the head of the leaf; caa-miri, the leaf torn from its mid-rib and veins with- out roasting; and caa-guaza, or yerva de palos of the Spaniards, which contains the whole leaf with leaf-stalks and small branches roasted. In consequence of these different qualities, and the crude mode of preparation in general use, it is found that the quantity of mineral matter in mate* is twice as great in some samples as in others. The average amount of tannin may be set down as 16 per cent., while the theine is present to the extent of about i *3 per cent. Mate* does not yield a wholesome beverage fit for habitual use. It acts upon the nervous system mainly, but it affects the digestive tract also, and often injuriously. The habitual use of hot, strong infusions of matd is very prejudicial to the general health, although the occasional employment of this food-adjunct after great fatigue is refreshing and restorative. But confirmed mate'-drinkers, like opium-eaters, prefer to give up their food rather than their daily allowance of mate*. Mate* is prepared for drinking by pouring boiling water upon a teaspoonful of the powdered leaves in a cup or calabash, adding a little sugar, and sucking up the infusion through a small tube or "bombilla." Guarana-bread is another substitute for tea. It is used extensively in Brazil and other parts of South America. It is prepared from the seeds of a small climbing plant (Paullinia sorUlis). The seeds are roasted, ground, mixed with a little TOBACCO. 205 for more than three centuries. Sir Walter Raleigh much promoted its use in England. In the year 1872 nearly 20,400 tons of unmanufactured tobacco were imported into this country, half of this quantity being from the United States of America. The duty paid on the tobacco for home consumption amounted to ^6,694,000 in the above-named year. It appears that there are several species of plants which yield the tobacco of commerce, although they are all included in the genus Nicotiana. The most abundant sort is furnished by N. Taiacum; N. rustica is said to yield the East Indian tobacco, as well as Latakia and Turkish; while N. persica is the tobacco of Shiraz. Other species are N. quadrivalvis, N. multivalvis, and N. repanda. But the distinctions between these plants, and the several sorts of prepared tobaccos which they are assumed to furnish, are not yet accurately known. Case 117. The composition of dried tobacco leaves varies greatly with the conditions of their growth, as well as with the sort of plant grown. The mineral matter is considerable (13 to 28 per cent.) and includes much nitre, the presence of which gives to the dry leaf its peculiar property of slowly smouldering away with slight deflagrations, like amadou or tinder. The most important principle or constituent of tobacco is, however, the nicotine, a nitrogenous substance of the group of the alkaloids. This nicotine has a very powerful action upon the nervous system, being a narcotic, like the morphine, narcotine, &c, found in opium. Some of the more delicate tobaccos of Havannah contain less than 2 per cent. of nicotine; the stronger tobaccos, as Virginian shag, contain 6 per cent. As much as 10 per cent. has been found in some samples grown in Europe. When the tobacco is burnt in the operation of smoking, the nicotine is in great part destroyed, other volatile alkaloids (picoline, &c.) being produced from it. These are contained in the smoke, are liquid, like nicotine, and are also poisonous. The average amount of water in commercial tobacco is 13 per cent. OPIUM. 207 as a sedative and anodyne, alleviating pains, and producing a quiet sleep. When smoked, as in China and many other parts of the world, it is generally consumed with tobacco or some other leaf in a pipe.* Indeed, many of the Chinese tobaccos contain opium. It produces a peculiar soothing effect, but the habitual use of opium is most hurtful to mind as well as body. After all it is doubtful whether opium should find a place in a food-collection. The same observation applies also to hemp. * Chinese opium, opium-pipes, and prepared tobaccos are shown in Case 139 (see National Foods). 208 FOOD-EQUIVALENTS. PART V.-OF DIET AND DIETARIES. The work and offices performed by human food have been already discussed in the First Part of this hand-book. What we propose to describe in the few pages which remain at our dis- posal is the nature of various actual dietaries. But we will first look at the relative values of different constituents and articles of food before we pass on to consider how these food-materials are actually employed in the daily rations of individuals, of groups of persons engaged in similar occupations, and of nations. § i.—Food-equivalents. As several different kinds of compound nutrients are necessary to sustain life and activity, to calculate the amount of carbon and the amount of nitrogen, &c., in a day,s ration will not alone suffice to show the dietetic value of that ration. We must first of all be sure that the carbon and the nitrogen are present in such forms as are practically available for nutrition. This being the case, we may assume that about 75 per cent. of the fat present in a dietary is carbon; 42 per cent. of the other heat-givers, and S3 per cent. of the flesh-formers, also consisting of the same element. If we take the hydrogen of all these nutrients into 210 FOOD AS A FORCE-PRODUCER. The necessary nitrogen for one day would be furnished by— 1. Gloucester cheese 2. Ripe dry peas ... 3. Scotch oatmeal 4. Eggs, mixed yolks and whites 5. Lean of beef ... 6. Wheaten flour ... 7. Bacon .... 8. Cleaned rice ... 9. Wheaten bread ... 10. 11. lb. o I 1 2 2 2 3 3 3 Cows' milk -.-.....6 Potatoes ........24 12. White turnips 54 15 3 10 o 1 8 4 7 13 S o 4 A glance at the preceding table will show that no one article of food taken alone can furnish the exact quantities, both of nitrogen and of carbon requisite for the day,s nourishment; cows' milk, however, occupies nearly the same position in both sections of the table. Potatoes, on the other hand, are so deficient in available nitrogen that nearly four times the weight of these tubers necessary to furnish the requisite quantity of carbon must be eaten in order that the former element may be taken in sufficient amount. To bring out the full meaning of the preceding table it should be studied in connection with the two tables which we now proceed to give. The quantities of different articles of food requisite for a day,s ration, so far as the important elements, nitrogen and carbon, are respectively concerned, having been now discussed, we may proceed to consider the relative amounts of work producible from 1 lb. of different important articles of food. The following table contains the results furnished by some of Dr. Frankland,s experiments:— Name of food. Tons raised 1 ft. high. Name of food. Tons raised 1 ft. high. Beef fat - . - 5.649 .Oatmeal - - 2.439 Butter - - 4.507 Arrowroot starch - 2,427 Cheshire cheese- - • 2,704 Wheaten flour - - 2.383 214 PUBLIC DIETARIES. 7. The Royal Engineers, when occupied in the South Ken- sington Museum, were found to eat an amount of food contain- ing 4^ oz. of flesh-formers, and 13 oz. of carbon daily. When the sailor or soldier retires from active work he naturally requires less amounts of flesh-forming and heat-giving nutrients in his food. It is found, however, that the carbon actually consumed is but little lower under these circumstances. Paupers in workhouses, of whom but little labour is expected, require less flesh-formers and carbon than active soldiers and sailors and artisans. Boys 10 years of age, at school, receive about half the flesh-formers required by active men, and about three-fourths the quantity of carbon. Ladies in luxurious repose consume about the same amount as young schoolboys. It must always be remembered that flesh-formers can be, and constantly are, used in the human body as force-producers; but, on the other hand, the heat-givers or force-producers (starch, sugar, and fat) cannot be applied to the formation of flesh. The dietaries of some of the classes of persons named in this paragraph are illustrated below: Case 127. 8. Greenwich pensioners receive 3^ oz. of flesh- formers and 10 oz. of carbon in their daily rations. 9. The Chelsea pensioners have 4 oz. of flesh-formers and 9j£ oz. of carbon. 10. The old men of Gillespie's Hospital, Edinburgh, have 3 oz. of flesh-formers and 10 oz. of carbon daily. 11. Paupers in our workhouses receive, on the average, 2j{. oz. of flesh-formers and 8% oz. of carbon only. 12. The boys of Christ's Hospital in London receive 2*4 oz. of flesh-formers and 7 oz. of carbon daily. It will be instructive to give the details of a few other dietaries in a somewhat different and more extended form. In the table which follows, we show the amounts of flesh-formers and of the two chief groups of heat-givers in eight dietaries of widely dif- ferent characters. No great degree of accuracy is attainable in NATIONAL FOODS. 217 nutrients has to be eaten in order to provide the requisite quantity of flesh-formers. But we may often trace several elements at work in the construction of national dietaries. Besides the local peculiarities of the vegetable and animal foods which are most abundant and attainable, we have the influence of those instinctive appetites for particular articles of food, which certainly exist however difficult of explanation they may be. Religious or super- stitious usages are also most important factors in the result in many instances, although they will not always serve to explain the abstention from certain perfectly wholesome and nutritious foods, or the consumption of absolutely noxious or useless materials like clay. But this aspect of the subject before us, though interesting as a study, could not be discussed without entering into very voluminous details as to the curiosities of food. We may, how- ever, give a few illustrative examples of national foods, citing those which are in common use in India, China, Japan, and Siam. Cases 130 to 152. Indian Foods. These include cereal grains, pulse, salep, arrowroot, fungi, oils, sugar, coffee, condiments, spices, and narcotics. Cases 133 to 139. Chinese Foods. These include wines and spirits, oils, confectionery, preserved fruits and vegetables, dried fruits and grains, bamboo shoots preserved, cinnamon and cassia buds, tobacco, teas and flowers for scenting them, brick-tea, gelatinous substances, condiments and spices • nor must we omit pipes for tobacco and opium smoking, chopsticks, &c. Amongst these products may be noted soy and an oil prepared from the soy bean; tea-seed oil; cakes not unlike some of those made by European confectioners; various preserved fruits and vegetables in sealed canisters—for in the art of thus preserving such perishable pro- ducts, the Chinese have long been skilful. The Chinese preserve some of their fruits, roots, flowers, &c., in brine or salt; some in treacle, and some in sugar. Arrowroot is largely made from the root of a water-lily in China, in the Tae-hoo lake districts. Amongst ANCIENT FOODS. 219 Continent, in the debris of bones discovered during recent years in many caves once inhabited by man, and in the lake-dwellings of Switzerland, Savoy, and Denmark. In these last instances the Case 146. evidence of the use of many fruits and grains has been furnished by the perfect preservation of these substances. Fish- hooks have also been found, together with other proofs of the use of animal foods. One of the most productive of all the Swiss lakes is that of Pfaffikon, in the canton of Zurich. Here remains of many kinds of food were disinterred from the peat of the lake- dwellings of Robenhausen. These lake-dwellings were built on piles, covered above with planking. In the case of some of these structures, no evidence of the use of metals by their builders has been detected; they belong to a stone age, locally anterior to those of bronze and iron. The food remains of these very early inhabitants of Europe are of high interest