no BOMBAY DUCKS 



us not be mistaken. I do not deny the adequacy of 

 natural selection to produce new species. Undoubtedly, 

 numberless species have arisen as the result of the 

 weeding out of the unfit ; but it seems to me that 

 natural selection alone is unable to explain organic 

 evolution. It is undoubtedly a factor in the origin of 

 species and probably the most important factor, but it 

 appears to be but one of many factors, several of which 

 have yet to be discovered. 



