Xlll 



Lamarck. But in the eyes of the naturalist of the "Beagle" (and, 

 probably, in those of most sober thinkers), the advocates of trans- 

 mutation had done the doctrine they expounded more harm than 

 good. 



Darwin's opinion of the scientific value of the ' Zoonomia ' has 

 already been mentioned. His verdict on Lamarck is given in the 

 following passage of a letter to Lyell (March, 1863) : — 



" Lastly, you refer repeatedly to my view as a modification of 

 Lamarck's doctrine of development and progression. If this is your 

 deliberate opinion there is nothing to be said, but it does not seem so 

 to me. Plato, Buff on, my grandfather, before Lamarck and others, 

 propounded the obvious view that if species were not created separately 

 they must have descended from other species, and I can see nothing 

 else in common between the ' Origin ' and Lamarck. I believe this 

 way of putting the case is very injurious to its acceptance, as it 

 implies necessary progression, and closely connects Wallace's and my 

 views with what I consider, after two deliberate readings, as a wretched 

 book, and one from which (I well remember to my surprise) I gained 

 nothing." 



" But," adds Darwin with a little touch of banter, " I know you 

 rank it higher, which is curious, as it did not in the least shake your 

 belief." (Ill, p. 14; see also p. 16, "to me it was an absolutely 

 useless book.") 



Unable to find any satisfactory theory of the process of descent with 

 modification in the works of his predecessors, Darwin proceeded to lay 

 the foundations of his own views independently ; and he naturally 

 turned, in the first place, to the only certainly known examples of 

 descent with modification, namely, those which are presented by 

 domestic animals and cultivated plants. He devoted himself to the 

 study of these cases with a thoroughness to which none of his prede- 

 cessors even remotely approximated; and he very soon had his reward 

 in the discovery " that selection was the keystone of man's success in 

 making useful races of animals and plants." (I, p. 83.) 



This was the first step in Darwin's progress, though its immediate 

 result was to bring him face to face with a great difficulty. " But how 

 selection could be applied to organisms living in a state of nature 

 remained for some time a mystery to me." (I, p. 83.) 



The key to this mystery was furnished by the accidental perusal of 

 the famous essay of Malthus ' On Population ' in the autumn of 1838. 

 The necessary result of unrestricted multiplication is competition for 

 the means of existence. The success of one competitor involves the 

 failure of the rest, that is, their extinction ; and this " selection " is 

 dependent on the better adaptation of the successful competitor to 

 the conditions of the competition. Variation occurs under natural, no 

 less than under artificial, conditions. Unrestricted multiplication 



