Preserved and canned meats should be eaten with the utmost caution, not only because of the inferior meat used in the preparation of these foods, but also from the fact that they may become putrid after being canned.
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 the connective tissue forming the sheath of the muscle and of bundles of muscles, the skin, tendons, and the casein of bone. Gelatines 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 upon cooling.
While the gelatinoids are not muscle, they keep the muscles from being consumed when starches, sugars, and fats are lacking, and, in this sense, may be considered more in the nature of carbohydrates.
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.