GENERAL PRINCIPLES OF BREEDING. 21 



to changed conditions and of climatic influ- 

 ences, to which I have just referred. And yet 

 there is as great a divergence from a uniform 

 type in the human race as in any of the lower 

 orders of animals that are recognized as belong- 

 ing to a single species. 



In the practical business of breeding domes- 

 tic animals it is important that due promi- 

 nence be given to the operation of the laws to 

 which I have alluded, for it follows that a race 

 or breed most perfectly adapted to a certain 

 locality, a certain mode of life, conditions of 

 climate, and character of subsistence, may, in 

 time, when transported to a distant clime, or 

 even when subjected to changed conditions 

 of life in the same locality, lose all its distin- 

 guishing characteristics and become practi- 

 cally worthless. On the other hand, a race 

 of but little value in its native state may be so 

 modified by a change in climatic conditions, 

 or by the character, quality and quantity of 

 the aliment furnished, as to become of the 

 highest value to the breeder; and these modi- 

 fications, although frequently so slow as to be 

 almost imperceptible in a single generation, 

 are accelerated by the power of inheritance 

 under a continuation of the conditions which 

 inaugurated them. A high or low temperature, 

 and abundant or scanty nutrition, will, as be- 

 fore stated, affect physical development either 



