MUTATION 165 



acquisition or loss of unit characters. Darwin's 

 position has been sadly misrepresented by those 

 neo-Darwinians who have insisted that Natural 

 Selection operates only upon variations of the 

 quantitative order. In the Origin of SpecieSj 

 Darwin was arguing for continuity and natural 

 law, and accepted the principle " natura non facit 

 saltum " as in accord with the new view. Con- 

 tinuity in nature was his great argument against 

 creation. " Why," he asks, " should all the parts 

 and organs of many independent beings, each 

 supposed to have been separately created for its 

 special place in nature, be so invariably linked 

 together by gradated steps? " Fifty years ago, 

 we must remember, it was the battle of continu- 

 ity against special creation that was being fought 

 and not the gradual as opposed to the sudden 

 appearance of a unit character. 



Recognizing, then, that the mutation theory, 

 far from being opposed to Darwin's theory of 

 the origin of species, would have been welcomed 

 by him, we pass with more satisfaction, on the 

 occasion of this celebration, to a detailed consid- 

 eration of some of the facts of mutation. 



MUTATIONS IN NATUEE 



The classical case of mutation is that of the 

 evening primrose, named after Lamarck, but 

 henceforth to be no less closely Hnked with the 

 name of his evolutionary successor, De Vries. 



