OLD AND NEW THEORIES COMPARED. 337 



must bear in mind that when I made this analysis of 

 the ' Philosophic Zoologique ' in 1832, 1 was altogether 

 opposed to the doctrine that the animals and plants 

 now living were the lineal descendants of distinct 

 species, only known to us in a fossil state, and .... 

 so far from exaggerating, I did not do justice to the 

 arguments originally adduced by Lamarck and G-eoffroy 

 St. Eilaire, especially those founded on the occurrence 

 of rudimentary organs. There is therefore no room 

 for suspicion that my account of the Lamarckian 

 hypothesis, written by me thirty-five years ago, derived 

 any colouring from my own views tending to bring it 

 more into harmony with the theory since propounded 

 by Darwin." * So little difference did Sir Charles Lyell 

 discover between the views of Lamarck and those of his 

 successors. 



With the identity, however, of the main proposition 

 which both Lamarck and Mr. Darwin alike endeavour to 

 establish, the points of agreement between the two writers 

 come to an end. Lamarck's great aim was to discover the 

 cause of those variations whose accumulation results in 

 specific, and finally in generic, differences. Not con- 

 tent with establishing the fact of descent with modifica- 

 tion, he, like his predecessors, wishes to explain how it 

 was that the fact came about. He finds its explanation 

 in changed surroundings that is to say, in changed 

 conditions of existence as the indirect cause, and in 

 the varying needs arising from these changed condi- 

 tions as the direct cause. 



According to Lamarck, there is a broad principle 

 * Vol. ii. chap, xxxiv., ed. 1872. 



Z 



