The _extractives_ consist of a substance within the lean meat, known as creatin. This creatin is not a food; it is an appetizer, and gives to cooked meats, broths, etc., their pleasing flavor. In case of anaemia where it is necessary to build up red blood corpuscles, it is desirable to have the patient take the blood of beef, the thought of which is usually repellant, but it may be made very palatable if it is heated sufficiently to bring out the extractives, or flavor, 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. One reason why meat soups constitute the first course at dinner is because the extractives stimulate the appetite and start the flow of gastric juices. Bouillons contain no nourishment, because the proteins have been coagulated by the vigorous boiling, but they may be used as a basis for vegetables, rice, or barley to give them flavor. The best method is to make one’s own soup from the connective tissues (gelatinoids) and meat tissue. * * * * * [Sidenote: Eggs] Eggs consist chiefly of two nutrients,—protein, and fat (ten per cent), combined with water, phosphorous, and ash. Eggs are a wholesome source of protein and are, therefore, classed as nitrogenous foods. The fat and the iron are in the yolk, which is about one-third fat. The yolk also contains phosphorous and some ash. The white is practically free from fat but contains sulphur, phosphorous and a very little ash. The white and the yolk contain almost equal quantities of protein. The white of the egg is said to be pure albumen; the chief ash constituent is common salt. The total phosphorous in the white of the egg is equivalent to about two per cent phosphoric acid and the total phosphorous in the yolk is equivalent to one per cent. The dark stain made by eggs on silver is due to the sulphur contained in them. The iron in the egg is valuable to assist in building red corpuscles. The large part of the egg, as other proteins, is changed, mostly in the stomach, into peptone, absorbed as peptone and then changed back again into protein after absorption. That not digested in the stomach is changed in the intestine, as is the case with other proteins. Eggs are, no doubt, excellent articles of food for nutrition and for tissue building. They contain more water than cheese, but are more concentrated than milk or oysters. They have practically the same relative value in the diet as meat, and make a very good substitute for meat. Egg yolk in abundance is often prescribed where it is necessary to supply a very nutritious and easily assimilated diet.