When thus deprived of his virile functions the animal ceases, in effect, to exist as one of a species, but maintains an essentially individual life, in which the assimilable nutriment which he absorbs, instead of being in part appropriated to the office of reproduction of his kind, is all devoted to his own individual conservation. In animals not used for draught purposes, or in other labor, when the food received is nearly always in excess of the amount required for the support of the organism, the result follows that the surplus of nutritive substances (found sometimes in great abundance) becomes stored in the connective tissue and intermuscular structure, and that in this way the flesh assumes superior and more nutritious qualities than that of the unaltered animal, while, at the same time, it loses the strong and peculiar odor frequently communicated to it by the presence of the testicular apparatus and secretion in the entire animal. This property of modification of function is probably still better illustrated in the effect of the operation upon cows, where we shall find not only the power of accumulation of fat increased by castration, but, above all, the milky secretion improved both in quality and quantity, and also in the duration of the flow. AGE. The question, “at what age can an entire animal be altered?” admits of a simple answer, to wit, “as soon as the testicles can be easily reached--as soon as they appear outside of the abdominal cavity, and are found in the inguinal canal.” But although it can be performed at that epoch, or deferred to any period of after life, it must be remembered that it is easier and less dangerous in young than in older animals, and that with the former it is a simple operation, producing, ordinarily, no noticeable alteration in the other functions, and but rarely followed by accidents. A period between eighteen months and two years is generally preferred for horses, though, according to some authors, even a much earlier date may be chosen, some English veterinarians being accustomed to operate at as early a date as ten days from birth. It is immaterial, however, at what precise time the operation may be performed, since it is a conceded point that the earlier it is done the better. SEASON.