DARWIN'S CLAIM TO DESCENT. 197 



flower to the other, it is equally preposterous to 

 account for the structure of this parasite, with its rela- 

 tions to several distinct organic beings, by the effects 

 of the external conditions, or of habit, or of the voli- 

 tion of the plant itself." 



Doubtless it would be preposterous to refer the 

 structure of either woodpecker or mistletoe to the 

 single agency of any one of these three causes; but 

 neither Lamarck nor any other writer on evolution 

 has, so far as I know, even contemplated this; the 

 early evolutionists supposed organic modification to de- 

 pend on the action and interaction of all three, and I 

 venture to think that this will ere long be considered 

 as, to say the least of it, not more preposterous than 

 the assigning of the largely preponderating share in 

 the production of such highly and variously correlated 

 organisms as the mistletoe and woodpecker mainly 

 to luck pure and simple, as is done by Mr. Charles 

 Darwin's theory. 



It will be observed that in the paragraph last 

 quoted from, Mr. Darwin, more suo, is careful not to 

 commit himself. All he has said is, that it would be 

 preposterous to do something the preposterousness of 

 which cannot be reasonably disputed ; the impression, 

 however, is none the less effectually conveyed, that 

 some one of the three assigned agencies, taken singly, 

 was the only cause of modification ever yet proposed, 

 if, indeed, any writer had even gone so far as this. We 

 knew we did not know much about the matter our- 

 selves, and that Mr. Darwin was a naturalist of long 

 and high standing ; we naturally, therefore, credited 



