WHAT EVOLUTION IS 123 



cies comes from another, but how this 

 is accomplished no one apparently 

 can yet explain. As a contributing 

 factor, natural selection doubtless had 

 a hand in this operation, but it is in 

 the rough-hewing of the species, and 

 not in the polishing of the final prod- 

 uct that it is concerned. The polishing, 

 which after all is perhaps the most 

 essential aspect of the process, seems 

 still to be hidden from scientific gaze. 



