336 FROM THE GREEKS TO DARWIN 



scripts. He had also, as a matter of greatest in- 

 terest to us in the development of his views, 

 swung entirely away from any sympathy with 

 the theories of Buffon and Lamarck, and had 

 reached the extreme position as to the powers of 

 natural selection which he continued to hold for 

 some years. Several passages show this :^ 



External conditions (to which naturalists so often 

 appeal) do by themselves very little. How much they 

 do, is the point of all others on which I feel myself 

 very weak. I judge from the facts of variation under 

 domestication, and I may yet get more light. . . . 

 The formation of a strong variety or species I look at 

 as almost wholly due to the selection of what may be 

 incorrectly called chance variations or variability. 



Of the powers of natural selection he wrote 

 to Lyell in 1859: "Grant a simple Archetypal 

 creature, like the Mud-fish or Lepidosiren, with 

 the five senses and some vestige of mind, and 

 I believe natural selection will account for the 

 production of every vertebrate animal." But he 

 was more cautious in publication, for in the first 

 edition of the Origin of Species, which appeared 

 in the same year, he said: "I am convinced that 

 Natural Selection has been the main but not ex- 

 clusive means of modification." 



The contrast between Darwin's selection the- 



^Letter to Hooker, Nov. 23, 1856. 



