The Flesh of Animals.—During the period between the birth and maturity of animals their flesh undergoes very considerable changes. For instance, when the animal is young, the fluids in the tissues of the muscles contain a large proportion of albumin and gelatin. This albumin, which is also the chief component of the white of eggs, and is the essential constituent of protoplasm, the physical basis of life, possesses the peculiarity of coagulating or hardening at a certain temperature (160° F., the cooking point of meat) like the white of a boiled egg, and becomes no longer soluble or capable of being dissolved in water. As animals grow older gelatin gradually decreases in proportion to the fibrin (an organic compound substance which constitutes the solid matter that is deposited when blood coagulates) and to the other constituents of the flesh. The reason, therefore, why veal, lamb and young pork are white when cooked is that the large quantity of albumin contained in the fibres hardens, or becomes coagulated. The chief characteristic of young meat is the great proportion of gelatin contained in those parts that afterwards become hard or bony.
The quality of the flesh of animals is influenced considerably by the nature of the food on which they have been fed, for the food supplies the material which produces the flesh. If the food is not suitable and good, the meat will necessarily be inferior. The flesh of animals fed on farinaceous produce, as corn, pulse, etc., is firm, well-flavoured and also economical in the cooking; the flesh of those fed on juicy and pulpy substances, as roots, possesses these qualities in a somewhat less degree; but the flesh of those whose food contains fixed oil, as linseed, is greasy, high-coloured and gross in the fat, and if such food has been used in large quantities, will have a rank flavour.
Health of Animals.—It is indispensable to the good quality of meat that the animal should be perfectly healthy when slaughtered. However slight the disease in an animal may be, inferiority in the quality of its flesh as food is certain to follow. In many cases, indeed, the flesh of diseased animals has a tendency to very rapid putrefaction, and becomes not only unwholesome, but absolutely poisonous to those who eat it.
The Treatment of the Animal before it is Slaughtered is another circumstance which greatly affects the quality of meat, and has an important influence on its value and wholesomeness. This will be readily understood if we consider the laws in accordance with which the life of an animal is supported and maintained. These are the digestion of its food and the assimilation of that food into its substance. Nature in effecting this process, first reduces the food in the stomach to a state of pulp, under the name of chyme, which passes into the intestines and is there divided into two principles, each distinct from the other. One, a milk-white—fluid the nutritive portion—is absorbed by the innumerable vessels which open upon the mucous membrane, or inner