20 per cent., whereas mutton contains about 18 per cent., veal, 165, and pork, 10; the flesh is also firmer, more satisfying, and is supposed to be more strengthening than mutton, whereas the latter is more digestible. The flesh of young animals, such as lamb and veal, is less digestible and less nutritious. Pork is comparatively indigestible and contains a large amount of fat.

Flesh contains:-(1) Nitrogenous bodies: myosin, serum-albumin, gelatin (from the interstitial fibrous connective tissue); elastin (from the elastic tissue), as well as hæmoglobin. (2) Fatty matters, including lecithin and cholesterin. (3) Extractive matters, some of which are agreeable to the palate, e.g., osmazome, and others, which are weakly stimulating, e.g., kreatin. Besides, there are sarcolactic and inositic acids, taurin, xanthin, and others. (4) Salts, chiefly of potassium, calcium, and magnesium. (5) Water, the amount of which varies from 15 per cent. in dried bacon to 39 in pork, 51 to 53 in fat beef and mutton, to 72 per cent. in lean beef and mutton. (6) A certain amount of carbo-hydrate material is found in the flesh of some animals, in the form of inosite, dextrin, grape sugar, and (in young animals) glycogen.

TABLE OF PER-CENTAGE COMPOSITION OF BEEF, MUTTON, PORK, AND VEAL.--(LETHEBY.)

Together with the flesh of the above-mentioned animals, that of the deer, hare, rabbit, and birds, constituting venison, game, and poultry, should be added as taking part in the supply of nitrogenous substances, and also fish-salmon, eels, &c., and shell-fish, e.g., lobster, crab, mussels, oysters, shrimps, scollops, cockles, &c.

TABLE OF PER-CENTAGE COMPOSITION OF POULTRY AND FISH.(LETHEBY.)

(Singularly devoid of fat, and is therefore generally eaten with bacon or pork.)

(7:39 consist of non-nitrogenous matter and loss.) (Payen.)

Even now the list of fleshy foods is not complete, as the flesh of nearly all animals has been occasionally eaten, and we may presume that except for difference of flavour, &c., the average composition is nearly the same in every case.

II. Milk. Is intended as the entire food of young animals, and as such contains, when pure, all the elements of a typical diet. (1) Albuminous substances in the form of casein, and serumalbumin. (2) Fats in the cream. (3) Carbohydrates in the form of lactose or milk sugar. (4) Salts, chiefly calcium phosphate; and (5) Water. From it we obtain (a) cheese, which is the casein precipitated with more or less of fat according as the cheese is made of skim milk (skim cheese), of fresh milk with its cream (Cheddar and Cheshire), or of fresh milk plus cream (Stilton and double Gloucester). The precipitated casein is allowed to ripen, by which process some of the albumen is split up, with formation of fat. (8) Cream, consists of the fatty globules incased in casein, and which being of low specific gravity float to the surface. (7) Butter, or the fatty matter deprived of its casein envelope by the process of churning. (8) Butter-milk, or the fluid obtained from cream after butter has been formed; very rich therefore in nitrogen. (e) Whey, or the fluid which remains after the precipitation of casein; it contains sugar, salt, and a small quantity of albumen.

TABLE OF COMPOSITION OF MILK, BUTTER-MILK, Cream, and
CHEESE. (LETHEBY AND PAYEN.)

III. Eggs. The yelk and albumen of eggs are in the same relation as food for the embryoes of oviparous animals that milk

R

is to the young of mammalia, and afford another example of the natural admixture of the various alimentary principles.

TABLE OF THE PER-CENTAGE COMPOSITION OF FOWLS' EGGS.
Nitrogenous substances. Fats.

Salts.

Water.

by vegetarians, as the chief Those chiefly used are peas,

IV. Leguminous fruits are used source of the nitrogen of the food. beans, lentils, &c., they contain a nitrogenous substance called legumin, allied to albumen. They contain about 25.30 per cent. of this nitrogenous body, and twice as much nitrogen as wheat.

B. Foods containing carbohydrate bodies chiefly.

I. Bread, made from the ground grain obtained from various so-called cereals, viz., wheat, rye, maize, barley, rice, oats, &c., is the direct form in which the carbohydrate is supplied in au ordinary diet. Flour, however, besides the starch, contains gluten, a nitrogenous body, and a small amount of fat.

TABLE OF PER-CENTAGE COMPOSITION OF BREAD AND FLOUR.

Various articles of course besides bread are made from flour, .., sago, macaroni, biscuits, &c.

II. Vegetables, especially potatoes.

sugar.

They contain starch and

III. Fruits contain sugar, and organic acids, tartaric, malic, citric, and others.

C. Substances supplying fatty bodies principally. The chief are butter, lard (pig's fat), suet (beef and mutton fat).

D. Substances supplying the salts of the food. Nearly all the foregoing substances in A, B, and C, contain a greater or less amount of the salts required in food, but green

vegetables and fruit supply certain salts, without which the normal health of the body cannot be maintained.

E. Liquid foods.

Water is consumed alone, or together with certain other substances used to flavour it, e.g., tea, coffee, &c. Tea in moderation

is a stimulant, and contains an aromatic oil to which it owes its peculiar aroma, an astringent of the nature of tannin, and an alkaloid, theine. The composition of coffee is very nearly similar to that of tea. Cocoa, in addition to similar substances contained in tea and coffee, contains fat, albuminous matter, and starch, and must be looked upon more as a food.

Beer, in various forms, is an infusion of malt (barley which has sprouted, and in which its starch is converted in great part into sugar), boiled with hops and allowed to ferment. Beer contains from 12 to 8.8 per cent. of alcohol.

Cider and Perry, the fermented juice of the apple and pear.

Wine, the fermented juice of the grape, contains from 6 or 7 (Rhine wines, and white and red Bordeaux) to 24—25 (ports and sherries) per cent. of alcohol.

Spirits, obtained from the distillation of fermented liquors. They contain upwards of 40-70 per cent. of absolute alcohol.

Effects of cooking upon Food.

In general terms this may be said to make food more easily digestible; this usually implies two alterations,-food is made more agreeable to the palate and also more pleasing to the eye. Cooking consists in exposing the food to various degrees of heat, either to the direct heat of the fire, as in roasting, or to the indirect heat of the fire, as in broiling, baking, or frying, or to hot water, as in boiling or stewing. The effect of heat upon (a) flesh is to coagulate the albumen and colouring matter, to solidify fibrin, and to gelatinize tendons and fibrous connective tissue. Previous beating or bruising (as with steaks and chops), or keeping (as in the case of game), renders the meat more tender. Prolonged exposure to heat also developes on the surface certain empyreumatic bodies, which are agreeable both to the taste and smell. By placing meat in hot water, the external coating of albumen is coagulated, and very little, if any, of the constituents of the meat are lost afterwards if boiling be prolonged; but if the constituents of the meat are to be extracted, it should be exposed

to prolonged simmering at a much lower temperature, and the "broth" will then contain the gelatin and extractive matters of the meat, as well as a certain amount of albumen. The addition

of salt will help to extract myosin.

The effect of boiling upon (b) an egg is to coagulate the albumen, and this helps to render the article of food more suitable for adult dietary. Upon (e) milk, the effect of heat is to produce a scum composed of albumen and a little casein (the greater part of the casein being uncoagulated) with some fat. Upon (d) vegetables, the cooking produces the necessary effect of rendering them softer, so that they can be more readily broken up in the mouth; it also causes the starch grains to swell up and burst, and so aids the digestive fluids in penetrating into their substance. The albuminous matters are coagulated, and the gummy, saccharine and saline matters are removed. The conversion of flour into dough is effected by mixing it with water, and adding a little salt and a certain amount of yeast. Yeast consists of the cells of an organised ferment (Torula cerevisia), and it is by the growth of this plant, which lives upon the sugar produced from the starch of the flour, that a quantity of carbonic acid gas and alcohol is formed. By means of the former the dough rises. Another method of making dough consists in mixing the flour with water containing a large quantity of carbonic acid gas in solution.

By the action of heat during baking (d) the dough continues to expand, and the gluten being coagulated, the bread sets as a permanently vesiculated mass.

I. Effects of an insufficient diet.

Hunger and Thirst.-The sensation of hunger is manifested in consequence of deficiency of food supplied to the system. The mind refers the sensation to the stomach; yet since the sensation is relieved by the introduction of food either into the stomach itself, or into the blood through other channels than the stomach, it would appear not to depend on the state of the stomach alone. This view is confirmed by the fact, that the division of both pneumogastric nerves, which are the principal channels by which the brain is cognisant of the condition of the stomach, does not appear to allay the sensations of hunger. But that the stomach has some share in this sensation is proved by the relief afforded, though only temporarily, by the introduction of even non-alimen