predigested in order to render it more easily digestible for individuals suffering from gastro-intestinal disorders. This process is readily accomplished by adding an active preparation of pepsin to acidulated milk, and allowing the fermentation to proceed under the influence of heat at the body-temperature by immersion in hot water. During this fermentation the casein is partly or completely converted into albumoses. If the process is allowed to continue too long, the milk becomes bitter. For this reason it is ordinarily removed from the hot water after a few minutes, and is placed upon ice, which prevents further fermentation. In order to predigest milk in alkaline solution pancreatin is substituted for pepsin; pancreatization of milk has now largely replaced peptonization. In order to effect pancreatization of milk Fairchild's peptonizing tubes are ordinarily employed. These tubes contain five grains of pancreatic extract and fifteen grains of sodium bicarbonate. Each tube contains sufficient powder to digest one pint of milk. Another easy method of partially pancreatizing milk is by the use of Fairchild's peptogenic milk powder. First dissolve the powder in the water by rubbing and stirring with a spoon, then add the milk and cream; mix well; heat in a saucepan, with constant stirring until blood-warm-not too hot to be agreeably borne by the mouth; keep at about this temperature for ten minutes; then bring quickly to boiling-point; pour at once into clean bottle, shake thoroughly, cork tightly, and place directly on ice or in a very cold place.

Where the taste of pancreatized milk proves objectionable, the addition of carbonated waters, or of small quantities of coffee, may render it more palatable.

The digestibility of milk may be increased by the addition of hot or cold water, carbonated waters, such as Vichy or Apollinaris, lime-water, oatmeal or barley-water, or farinaceous foods, such as arrow-root or flour; occasionally small quantities of salt or sodium bicarbonate are helpful.

Kumiss, Kefir, and Matzoon.-Kumiss is a fermented drink prepared by both lactic acid and alcoholic fermentation. For many centuries it has been made from mares' milk by the natives living near the shores of the Caspian Sea. The milk is obtained from a special breed of mares, the animals being fed very carefully. The milk is mixed with a kumiss ferment, the lactic acid ferment converting some of the sugar into lactic acid, while another part of the sugar is converted into alcohol and carbonic acid; a small quantity of casein is digested. The milk

is constantly agitated, and the fermentation allowed to proceed for a period of twenty-four hours or more.

Kumiss is an acid, effervescing drink, and contains a very small proportion of alcohol. It is very easily digested, being much more digestible than milk. The casein is so finely divided that lumps cannot be formed in the stomach, and it is easily acted upon by the gastric secretion. In the United States it has been prepared from cows' milk, to which the ferment has been added.

Kumiss Cure. In certain parts of Russia this form of cure is not uncommon. It consists in drinking small quantities of kumiss and gradually increasing them until large quantities are taken. Kumiss cures have been prescribed in chronic gastro-intestinal catarrhs and chronic catarrhs of the respiratory

tract.

Kefir resembles kumiss, and is often used as a substitute for it. It was originally made in the Caucasus from cows' milk fermented with Saccharomyces mycoderma, lactic acid fermentation going on at the same time. Alcohol, lactic acid, and albumins are formed as a result of the fermentative processes. The casein is partly digested. Tablets of the kefir ferment have been prepared by Jurock, and are sold under the name of kefilac tablets. They render the home manufacture of kefir an easy matter. (See Recipes.)

Matzoon. In this form of milk lactic acid is produced by fermentation with a ferment obtained from Syria. It is thicker than kumiss and does not contain alcohol.

Kumiss, kefir, and matzoon are agreeable forms of milk foods, are easily digestible, and are especially useful in those cases in which milk cannot be taken or is not well borne. The following table is taken from Hutchinson and gives the composition of kumiss, kefir, etc. :

EGGS.

Eggs, like milk, form a complete food—that is, they contain a proportion of each of the fundamental food elements necessary for the preservation of life. Eggs and milk are the only complete food-products furnished by the animal kingdom.

The eggs of the hen are consumed in largest numbers, but those of the duck, turkey, guinea-hen, and of some wild fowl are also eaten. The eggs of domestic fowls vary in size and appearance, but their composition is about the same.

The shell of a hen's egg constitutes 11 parts, the white 57 parts, and the yolk 32 parts of the entire weight of the egg. The following table, taken from Langworthy,' shows the composition of hens' eggs, cooked and raw; of white-shelled and of brown-shelled eggs; and of the yolk and white of the egg of the duck, goose, turkey, and guinea-fowl :

As may be seen from the foregoing table, the egg contains mainly protein and fats, in addition to water and mineral The white and the yolk differ in composition, the

matter.

1 Farmers' Bulletin No. 128, United States Department of Agriculture.

Ash.

Fuel

value per pound.

white containing less protein and water than the yolk, and scarcely any fat and ash, whereas the yolk contains considerable fat and ash. The white is said to be pure protein; it is composed mainly of four albumins and a slight amount of carbohydrate. The albumins are ovalbumin, conalbumin, ovomucin, and ovomucoid, the ovalbumin being the main constituent. The yolk of the egg is very complex in composition, and contains 15 per cent. of protein (vitellin), 20 per cent. of palmitin, olein, and stearin (the fatty elements), and 0.5 per cent. of coloring-matter, besides lecithin, nuclein, salts of iron, calcium, potassium, and magnesium; the total phosphorus equivalent in the yolk is slightly over 1 per cent., while that of the white is but 0.03 per cent. The shell of the hen's egg has no food-value; it consists mainly of mineral matter containing 94 per cent. of calcium carbonate.

1

The flavor of the egg is dependent in large measure upon the food eaten by the laying hen. Fresh eggs have the finest flavor. Langworthy gives the following methods for testing the freshness of eggs: "Candling,' as it is called, is one of the methods most commonly followed. The eggs are held up in a suitable device against a light. The fresh egg appears unclouded and almost translucent; if incubation has begun, a dark spot is visible, which increases in size according to the length of time incubation has continued. A rotten egg appears dark colored. The age of eggs may be approximately judged by taking advantage of the fact that as they grow old their density decreases through evaporation of moisture." According to Siebel, a new-laid egg placed in a vessel of brine made in the proportion of two ounces of salt to one pint of water will at once sink to the bottom. An egg one day old will sink below the surface, but not to the bottom, while one three days old will swim about just immersed in the liquid. If more than three days old, the egg will float on the surface, the amount of shell exposed increasing with age. If the egg is two weeks old, only a little of the shell will dip in the liquid. Penzoldt gives the following table showing the digestibility of eggs:

2

2 soft-boiled eggs leave the stomach in 13 hours.

2 raw eggs leave the stomach in 24 hours.

2 poached eggs and 5 grams of butter leave the stomach in 24 hours.

2 hard-boiled eggs leave the stomach in 3 hours.

2-egg omelet leaves the stomach in 3 hours.

1 Farmers' Bulletin No. 128.

2 Hutchison, Food and Dietetics, p. 152.

The fact that raw eggs remain in the stomach longer than soft-boiled eggs is due to the fact that they are so bland that they excite neither the motor nor the secretory function; if thoroughly masticated, hard-boiled eggs are as digestible as soft-boiled ones. With some persons eggs in any form are indigestible, and produce unpleasant eructations, nausea, and headache.

Raw eggs are best taken directly from the shell, or they may be combined with milk broths or with coffee. In various diseases accompanied by loss of flesh and strength raw eggs in large numbers are prescribed, as many as 24 eggs being given in twenty-four hours.1

Egg-albumin is best absorbed when eaten raw and properly diluted. Its palatability may be increased by flavoring it with sherry wine, orange, lemon, or grape juice, or by serving it in cream, cocoa, or coffee.

Egg-nog is prepared from milk and eggs, flavored with some alcoholic drink, and sweetened with sugar.

When allowed to remain in the air, eggs decompose from the entrance of germs through their shell. Decomposition may be prevented in various ways, such as by coating them with oil or varnish, packing them in sawdust, or placing them in cold storage or in certain solutions, such as salicylic acid and glycerin.

MEATS AND THE MEAT PREPARATIONS.

Meat forms the fleshy or muscular parts of the body. It is one of the most important articles of food, and is the chief source of man's protein supply. Meat may be eaten raw or cooked. Raw meat, when well ground, is very easily digested.

Meat is composed of muscle-fibers held together by connective-tissue bands; between the muscle-fibers are bits of fat. As ordinarily seen, meat contains muscle tissue, connective tissues, blood-vessels, nerves, and lymphatics, together with a varying amount of fat. The more fat there is in meat, the less water and nitrogenous matter does it contain, and vice versa. Cooking has the effect of rendering the connective tissues soluble, thereby causing a separation of the muscular fibers, allowing the digestive secretion to mingle more thoroughly with them. Cooking also enhances the flavor and appearance of the

1 Ely, "Fable of Egg," New York Med. Jour., November 14, 1903.