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THE 



>T [Vol. XLIII 



Accordingly Darwin has been charged with a radicalism 

 which he never professed and champions of a supposed 

 Darwinism have felt called upon to do battle against 

 theories which he never distinctly repudiated or which 

 he might even have accepted if he had known of them. 

 Thus, Professor Poulton, in his recently published 

 "Essays on Evolution/' attacks with great severity, un- 

 der the name of " Batesonians, " believers in the validity 

 of mutation as a factor in the process of evolution, 

 although, as he admits, "mutation was of course well 

 known to Darwin." 3 Now, I think we are justified in 

 saying that if mutation was "known" to Darwin, it must 

 have been, and still is, a veritable fact; and, if evolution 

 is a universal law of nature it can not, in that case, ex- 

 clude mutation. We, therefore, who believe in general 

 evolution are compelled to decide for ourselves whether 

 mutation has taken place and is now occurring; and we 

 who are really Darwinians— that is to say, we who believe 

 that Darwin set forth correctly the essential steps in the 

 evolutionary process — are interested in knowing whether 

 he actually recognized the fact of "discontinuous varia- 

 tion" or mutation, and, if so, how he fitted it into or 

 reconciled it with his system. 



The essential factors in organic evolution, from the 

 Darwinian point of view, are: (1) Variation, (2) inherit- 

 ance, (3) over-reproduction, (4) competition, (5) adapta- 

 tion, (G) selection and survival. The general explanation 

 of these factors is as follows : 



1. All organisms vary continually and in every part 

 of their structures -that is to say, no two individuals arc 

 exactly alike in any particular. 



•1. Xevertheless, characters anatomical, physiological 

 and psychological are in general transmitted to descend- 

 ants ; in other words, progeny essentially resemble their 



