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. Roasted young chicken and veal are tender, easily masticated, and easily and rapidly digested in the stomach. This is one reason why the white meats are considered a good diet for the invalid, though veal is usually avoided in cases of dyspepsia, as, if too young, it may cause diarrhea; if too old, it is less digestible than beef. Fat meats remain in the stomach a much longer time than lean meats; thus, gastric digestion of pork, which usually contains much fat, is especially difficult, requiring from three and one-half to four hours (see page 22). Preserved and canned meats should be eaten with the utmost caution, care being taken to know that they are put up by firms which use extreme care in their preparation. Inferior meat is sometimes used in the preparation of these foods. If meats are not fresh and the canning not carefully done, they may become putrid after being put up. _Fish_ and _sea foods_ are, many of them, rich in protein, as noted in Table IV. They should never be used unless absolutely fresh. The idea is prevalent that fish is a brain food. Fish is easily digested and builds brain as well as other tissue, but no more readily than beef does, or any easily digested, absorbed and assimilated food which contains a goodly proportion of protein. _Lobsters_ are difficult of digestion and contain little nutrition, so are not valuable as a food, though they are relished by many on account of their flavor. _Oysters_, raw, are easier to digest than when cooked. Oysters should not be eaten during the spawning season from May to September.