414 STERILITY OF HYBRIDS. 



their hybrids, is not a special endowment, but is inci- 

 dental on modifications slowly impressed, by unknown 

 means, on the reproductive systems of the parent 

 forms." 



There are three answers to be made to this view, 

 that the sterility of hybrids "is not a special endow- 

 ment, but is incidental on modifications, slowly im- 

 pressed, by unknown means, on the reproductive 

 systems of the parent forms." 



(i.) It is a barren assumption. Not the faintest in- 

 timation, or conjecture, does he give of the manner in 

 which this sterility might have been acquired. The 

 phrase, " unknown means " (a twin brother of " innate 

 tendency," of "nature and constitution of the being," 

 of "a great law of nature," and of that legion of other 

 metaphysical entities which serve him in good stead, 

 whenever he is in a dilemma), proves conclusively, 

 that he had as little idea of what he meant, when he 

 propounded his "view," as his readers may derive 

 from his proposition. _ 



(2.) There is not a scintilla of evidence, in his 

 works, which, upon the most liberal construction, can 

 be tortured into proof, that the sterility of hybrids was 

 ever acquired by modifications slowly impressed. 



(3.) There are modifications, which have been im- 

 pressed, and are still being impressed, by known means, 

 however, on the reproductive systems of the varieties 

 which he terms "incipient species," or "species in the 

 process of formation;" but, these modifications, so far 

 from accounting for the sterility of hybrids, consist- 

 ently with his hypothesis, demonstrate most clearly, 



