Darwinians against Darwin. 103 



racial varieties. If species are only the modifica- 

 tions of organic types produced by nat- 

 ural selection, how have they come to be f species.* 

 mutually sterile, when even greater mod- 

 ifications of such types, produced under our very 

 eyes by artificial selection, do so generally continue 

 fertile? There seems to be only one answer, that 

 the said natural species were never produced by 

 natural selection. 



114. In the second place, you suppose that uni- 

 form conditions of existence may have acted for 

 long periods of time on the physiological 2 Time aud 

 system of certain varieties, so as to make other 

 them mutually sterile, and thus create Accidents - 

 our present species. Such a supposition will not 

 stand. This sterility, to be of any use in the theory, 

 would have to arise at once when the variety or 

 race was just beginning to develop; it would have 

 had to protect the variety from intercrossing with 

 the original form, which otherwise would swamp it 

 forthwith. So we are to make the gratuitous sup- 

 position, that sterility arose all at once, at the pre- 

 cise moment it was wanted, and just by chance. 

 If you will insist upon supposing again (hypothesis 

 upon hypothesis, which is true Darwinism!) that 

 uniform conditions of life happened to act upon a 

 sufficient number of individuals, during the same 

 interminable periods of time and ever in the same 

 way; and effectually guarded the new develop- 

 ment, and happened to prevent intercourse with the 



