IN-BREEDING 219 



any other system or method of breeding. The particular 

 beneficial result most commonly claimed is that in-breed- 

 ing is the quickest method of fixing and perpetuating a 

 desirable character. Closely related animals are most 

 likely to possess the character sought, and mating animals 

 having the qualities which the breeder particularly desires 

 to perpetuate in the breed is the most natural method 

 of accomplishing his purpose. In-breeding tends to in- 

 tensify the good qualities which the breeder is striving 

 to make dominant. It does not cause new and desirable 

 characters to appear, but is merely a method of making 

 the greatest possible use of such characters. 



Thus in-bred animals are strongly prepotent. They 

 possess to an unusual degree the power of fixing their 

 qualities upon their offspring. This is manifestly the 

 most important characteristic in a highly improved breed- 

 ing animal. Next to the possession of the highly improved 

 characters which make the domestic animals useful to 

 man, their ability to transmit those qualities is most 

 important. In-breeding is one certain means of develop- 

 ing the prepotency of animals. 



It is a fundamental principle of breeding that the 

 smaller the number of qualities selected for improvement 

 by the breeder, the more rapid and certain will be his 

 progress in the improvement of the breed. In- 

 breeding tends to reduce the number of characters, sim- 

 plify the breeding operations, and thus makes more 

 certain the continued reappearance of the valuable 

 characters in succeeding generations. 



205. Bad results from in-breeding. In recounting 

 the well-known benefits which follow intelligent in-breed- 

 ing, it is not intended to convey the impression that 

 in-breeding results only in success. The biological pro- 



