318 



THE -AMERICAN NATURALIST 



[Vol. LIII 



delian reawakening. If his birds, judging by their feather 

 performance, are lacking a certain germ factor he is well 

 aware that he can by no possible means originate the 

 factor nor hope to produce it in any way ; he must pro- 

 cure it from some other farmer whose birds display it, 

 and then he may expect to secure it in combination in his 

 own strain. 



Ill 



''Selection only acts as a mechanical sorter of existing 

 diversities in the germ plasm and not as a cause of altera- 

 tion in it." 



The term selection" is employed by the ostrich 

 breeder in South Africa with all that freedom which Pearl 

 finds among the plant and animal breeders in America, 

 but he is never under any delusion that it signifies more 

 than is implied in the simple meaning of the word. He 

 has retained its plain ever^^day significance and the major- 

 ity have never heard of Darwin and ' ' The Origin of 

 Species by Means of Natural Selection," nor of the ex- 

 tended meaning which students of evolution are inclined 

 to give the term, as in the phrase, "The Selection Prob- 

 lem." To the ostrich farmer "breeding from selection" 

 simply means that for his breeding sets he picks out birds 

 having the s])0(*ial iilumago characters he desires to see in 

 tlicir proiit'iiy. or wliicli lie expects to get from the com- 

 biiiatinii of tlic cock and tlic lien. Selection is merely used 

 in contract with iiidiseriniinate breeding, as#where any 

 cock and hen may be camped off without regard to their 

 plumage value, or in contrast to breeding on the veld 

 where any cock may mate with any hen. He selects partly 

 on the basis of somatic performance and partly on proved 

 germinal production; many birds which themselves give 

 indifferent plumage are yet employed as breeders from 

 being known to produce superior chicks. 



From his life-long cxiXM ionce in selective breeding the 

 ostrich farmer clearly ura-p- that all he is doing is to sort 

 out birds from amonn- lil- (lock with certain characters 



