SELECTION AND MANAGEMENT 97 



fleece, are steadily weeded out. Under nature's 

 system the males of all animals of the deer and 

 sheep families roam far during the breeding season, 

 yet it is likely that incestuous breeding is very 

 common. 



The effect of incestuous breeding is not well 

 understood and there are men who deny its dangers. 

 There seems, however, to be abundant evidence that 

 it develops an accumulation of weaknesses of con- 



BLACK-FACED RAMS. 



stitution, it makes the progeny delicate and lessens 

 its size and vitality. 



Furthermore, it often seems to lead to partial or 

 total sterility. Not to go deeply into this debatable 

 subject we will say that inbreeding is probably abso- 

 lutely necessary in the creation of breeds and in the 

 further development and fixing of types, but that it 

 should be attempted only by the skilled breeder, the 

 man sure that he has a type worth fixing. The man 



