BREEDING, the process of organic pro creation. In this article the physiology of the matter is not to be considered, however, but only the methods and results as applied to the reproduction of domesticated animals and plants on varietal lines in accordance with human requirements or fancy— that is, selective breed ing. When men first began to keep flocks and heids and pet-animals, which were subjugated rather than domesticated as yet, reproduction was no doubt left wholly to nature, as still is the case on the vast cattle ranches of South Africa, Argentina and in America. But very early in the history of pastoral life (which, doubtless, was the first rise above savagery) selective influences must have begun to operate, especially in the case of those animals which are most closely associated with their owners, and therefore most constantly under observa tion and control. Not only from the earliest times of Egyptian and Oriental record, but long previous, as shown by sub-fossil remains, distinct varieties of dogs, horses, camels and cattle had been produced from their original wild stocks. This might have come about in part naturally as a result of migration of bands to novel climates and food, to inbreeding and to other influences entailed by even a semi domesticated condition; yet, no doubt, a rough sort of selective breeding began with the earliest domestication of live stock, poultry, etc. Favorites would be preserved when, in times of stress, others were killed for food. Owners fancying bigness, or speed, or a special color or some other quality in certain of their animals would try to get more of that particular kind. In both cases the saving of these better ones would, when they came to breed, strengthen the collection until a noticeable strain had been evolved without any definite intention or action by the owner.
It is probable, moreover, that observation and reasoning — in neither of which faculties was the primitive herdsman deficient within the limits of his experience — would soon suggest to him some advantageous choice of mates among his animals; and there is no question that selective breeding was understood in a practical way at the dawn of history. It is most strik ingly manifested in the care taken in ancient as in modern times in southwestern Asia, and in northern Africa, to keep pure and perfect the standard breeds of horses and camels. Little
progress was made in Europe in this direction, for various reasons, previous to or during the Middle Ages, and no one with influence made any study of the principles that underlie that proverb of contented credulity —°Like begets like.° Men were accustomed to choose as progenitors the best specimens available of the type they preferred, and were thankful when they got satisfactory progeny. The first at tempt at scientific treatment of the matter was that of Robert Bakewell in England, who, about the middle of the 18th century, studied and formulated the peculiarities of certain breeds of cattle, and showed how a male and a female excelling alike in the one or more selected characteristics must be used if the offspring were to progress along that desired line. Thus was begun the now familiar practice of sys tematically °breeding for points"— that is for the standard characteristics by which a breed (that is, an artificial variety) of any animal is distinguished. Such a breed, when finally at tained, continues to perpetuate its distinctive form, or, as they say, °breeds true,° by virtue of the laws of heredity. These laws cannot be discoursed of here, but a few words of explanation may be permitted. While it is true in general that °like begets like,° it is not so in all particulars. No two young are pre cisely like their parents, or exact duplicates of one another. Individual variations appear in size, color, proportions and temperament. Some differences are rarely noticeable, for some phys ical features are apparently too fundamental to suffer any perceivable alteration — teeth or eyes (except as to color) for example; other more superficial and plastic features frequently show diversities. The art of the breeder, who desires an improvement in a certain kind of domestic animal, either for increased usefulness, or for some fanciful end, is to recognize and profit by emphasizing some one of the plastic features, and to cultivate it at the expense of other fea tures. To do this he selects a pair that show a little more than others the desired quality. Some of their offspring are likely to exhibit this quality better than others of the litter, and these are mated. So progressive generations go on advancing the desired feature and eliminating undesirable ones. See HEREDITY; MENDEL'S LAW.