Under this influence the herd will deterior- 

 ate, although the individuals of the inferior 

 herd are no worse than their own actual par- 

 ents. Such a process is called race-degener- 

 ation, and it is the only race-degeneration 

 known in the history of cattle or men. The 

 scrawny, lean, infertile herd is the natural 

 offspring of the same type of parents. On 

 the other hand, if we sell or destroy the 

 rough, lean, or feeble calves, we shall have 

 a herd descended from the best. It is said 

 that when the short-horned Durham cat- 

 tle first attracted attention in England, the 

 long-horns which preceded them, inferior 

 for beef or milk, vanished " as if smitten 

 by a pestilence." The fact was that, being 

 less valuable, their owners chose to destroy 

 them rather than the finer Durhams. Thus 

 the new stock came from the better Dur- 

 ham parentage. If conditions should ever 

 be reversed and the Durhams were chosen 

 for destruction, then the long-horns might 

 again appear, swelling in numbers as if by 

 magic, unless all traces of the breed had in 

 the meantime been annihilated. 

 In selective breeding with any domesti- 



The 



Human 



Harvest 



[43] 



