BREEDING 



123 



that have resulted unfavorably, that we should look not to 

 the kinship of blood but the kinship of defect" for the diffi- 

 culty. Thus we may also say of the successes of line breeding 

 that they are attributable "not to the kinship of blood but 

 the kinship of superiority. . . . Success or failure with 

 in-breeding is clearly dependent upon selection." When 

 vigor and hatching power are the first basis of selection, less 

 will be heard of the evils of line breeding. 



Fig. 59 



Trap nests. (Courtesy of Kansas Experiment Station.) 



The following extract from a personal letter to the author 

 from Mr. D. W. Young, of Monroe, New York, one of the 

 very foremost breeders of fancy Single Comb White Leghorns 

 in America, serves as an excellent illustration of the possi- 

 bilities of intelligent inbreeding. 



"I really cannot tell how many birds my father first 

 brought over from Italy in 1853. I should judge from ten 

 to fifteen. However, in 1883 I started niy present lines 

 with one male and one female and now have seventeen 

 different lines. I can remember as far back as 1876 and can 

 make an affidavit that we have never had any new blood in 

 that time. * * * 



