PART III-—ANIMAL BREEDING 
CHAPTER XXVII 
THE GENERAL ASPECTS OF ANIMAL BREEDING 
From a scientific standpoint it would be practically useless in this 
treatment of genetics in relation to animal breeding to develop exten- 
sively the historical features of the subject; because they cannot be re- 
lated effectively and satisfactorily to a growing knowledge and application 
of the principles of variation and heredity, and because of the peculiar 
nature of many of the problems of animal breeding. Accordingly this 
chapter will be devoted for the most part to a discussion of the importance 
and possibilities of the breeding industry, and of the opportunity for 
service which genetics has therein. 
The History of Animal Breeding——The domestication of animals 
occurred very early in the history of man; so early that accurate historical 
documents do not carry us back within sight of the time when man first 
began to take wild animals under his care. The history of most of our 
domesticated animals, in fact, is very incomplete, and in many cases we 
can only conjecture as to the wild species which were probably subjected 
to domestication, or from the hybridization of which our tame breeds 
have had their origin. This difficulty of determining precisely what 
wild species have been utilized by prehistoric man, or in finding among 
wild species any which are obviously closely related to those under do- 
mestication, is in itself proof conclusive that improvement in herds of live- 
stock, kept at first perhaps in a state of semidomestication only, must 
have been coincident with the beginnings of domestication. Through 
long centuries of slow progress the level of excellence in early tribal herds 
had gradually been raised, partly by the action of factors unknown to 
and undirected by primitive herdsmen, partly under his conscious 
direction. As a result man has established numerous races more defi- 
nitely suited by far to his particular purposes than were their wild 
ancestors which roamed the plains or inhabited the forests. Conse- 
quently even at the dawn of history, domesticated animals had already 
been developed to a high state of excellence, when measured by their 
adaptability to particular local conditions of life and their suitability 
for the purposes for which they had been bred. 
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