44 DARWIN AND NATURAL SELECTION 



for existence taken place, and the climatic and 

 geologic conditions and changes been quite differ- 

 ent from what they have been " (p. 273) ; and, 

 still further in opposition to the neo-Darwinian 

 position, Korschinsky, a Russian, who holds that 

 " the struggle for existence, and the selection that 

 goes hand in hand with it, constitute a factor 

 which limits new forms and hinders further vari- 

 ation, and is, therefore, in no way favourable to 

 the origin of new forms. It is a factor inimical to 

 evolution." (p. 335). 



So much for the two poles of opinion : Weis- 

 mann is quite sure that natural selection can do 

 everything, because, if it cannot, one must believe 

 in a Divine Guide ; Nageli thinks that natural 

 selection can do nothing, and, it may be paren- 

 thetically remarked, has put forward a theory of 

 orthogenesis, which depends upon " a principle 

 of progressive development (Vervollkommungs- 

 prinzip), a something inherent in the organic 

 world which makes each organism in itself a force 

 or factor making towards specialization, adapta- 

 tion, that is, towards progressive evolution " 

 (p. 278) ; whilst Korschinsky, whose theory of 

 evolution is very similar to that just described, 

 will have nothing at all to do with natural selection 

 as a factor in progressive evolution, since he re- 

 gards it as a hindrance instead of an assistance. It 

 would certainly, however, be true to say that by 

 far the greater number of those whose names are 

 included in Kellog's list, given above, hold the 

 middle opinion. Nor would it be going too far, 

 we think, to say that the majority of biologists 



