144 EVOLUTION 



HUXLEY ON "THE QUINTESSENCE OP 

 DARWINISM." Huxley made this distinc- 

 tion between fact and factors very plain in 

 his essay "On the Reception of the Origin 

 of Species" in Darwin's "Life and Letters." 

 He first states the grounds of his own 

 agnostic position (up to 1858) with respect 

 to the doctrine of evolution as promulgated 

 by Lamarck, Robert Chambers, and even 

 Spencer: "Firstly, that up to that time the 

 evidence in favour of transmutation was 

 wholly insufficient; and, secondly, no sug- 

 gestion respecting the causes of the trans- 

 mutation assumed, which had been made, 

 was in any way adequate to explain the 

 phenomena." 



He goes on to say : 



"The suggestion that new species may 

 result from the selective action of external 

 conditions upon the variations from their 

 specific type which individuals present and 

 which we call "spontaneous" because we 

 are ignorant of their causation is as wholly 

 unknown to the historian of scientific ideas 

 as it was to biological specialists before 1858. 

 But that suggestion is the central idea of the 

 'Origin of Species,' and contains the quin- 

 tessence of Darwinism. . . . That which we 

 were looking for, and could not find, was an 

 hypothesis respecting the origin of known 



