The proportion of albuminoids, gelatinoids, and extractives in meat vary with different meats and with different cuts of the same meat.

The albuminoids of meat include the meat tissue, or the muscle cells. These constitute by far the greater part of the meat.

The gelatinoids are derived from the connective tissue forming the sheath of the muscle and of bundles of muscles, the skin, tendons, and the casing of bone. Gelatins are made from these and, if pure and prepared in a cleanly manner, they are wholesome.

Gelatin is distinguishable in rich meat soups, which jelly when cool.

The gelatinoids alone have not a large nutritive value; they serve to spare the albumin from being used, though they cannot replace albumin in the diet. They also, to some extent, keep the muscles from being consumed when starches, sugars, and fats are lacking.

The extractives are found most abundantly in the flesh of animals and birds noted for their muscular activity, as in game. Some of them exert a stimulant action on the nervous system and others are appetizers, giving to cooked meats, broths, etc., their pleasing flavor. In case of anemia, in which it is necessary to build red blood corpuscles, the blood of beef, the thought of which is usually repellent, may be made very palatable if it is heated sufficiently to bring out the flavor of the extractives, and then seasoned.

Unless the beef extracts on the market contain the blood tissue, in addition to the extractives, they are not particularly nourishing and are only valuable in soups, etc., as appetizers.

Soups for nourishment should be made by cooking the bones, connective tissue, and a part of the meat. Bones and connective tissue alone make an appetizing soup, but it contains little nutriment.

One reason why meat soups should constitute the first course at dinner is because the extractives stimulate the appetite and start the flow of gastric juices. Bouillons contain no nourishment, but they may be used as stimulant restoratives to the muscles, or as a basis for vegetables, rice, or barley to give them flavor.

Roasted flesh seems to be more completely digested than boiled meat; raw meat is more easily digested than cooked; rare meat is more easily digested than that thoroughly cooked.