84 OBGANIC EVOLUTION CONSIDERED 



With regard to cross-sterility, Darwin says: "After 

 mature reflection it seems to me that this could not. 

 have been effected through 'natural selection, for it 

 could have been of no direct advantage to an in- 

 dividual animal to breed badly with another individ- 

 ual of a different variety, and thus to leave few off- 

 spring; consequently such individuals could not have 

 been preserved or selected."* 



Again, he says: "That the sterility of first crosses, 

 and indirectly of hybrids, is simply incidental on un- 

 known differences in the reproductive systems of the 

 parent species. "f 



Mr. Spencer has written a series of articles entitled 

 "The Inadequacy of Natural Selection." As to arti- 

 ficial and natural selection he says: " They are anal- 

 ogous only within certain narrow limits, and in the 

 great majority of cases, natural selection is utterly 

 incapable of doing that which artificial selection 

 does. "J 



He quotes from Mr. Darwin: "Any particular 

 variation would soon be lost by crossing, reversion 

 and the accidental destruction of the varying individ- 

 uals, unless carefully preserved by man,"§ 



Mr. Spencer claims that " the inheritance of ac- 

 quired characters " is a necessary supplement to nat- 

 ural selection. Referring to his " Principles of Biol- 

 ogy," he says: "It was contended that the relative 

 powers of co-operative parts cannot be adjusted solely 

 by survival of the fittest, and especially where the 

 parts are numerous and the co-operation complex." 



After arguing this proposition at length, he says: 

 " Close contemplation of the facts impresses me 

 more strongly than ever with the two alternatives — 



* Origin of Species, p. 247. + Ibid, pp. 248-9. 



% Popular Science Monthly for April, May and June, 1893. 

 § Animals and Plants under Domestication, Vol. II., p. 292. 



