252 LAY SERMONS, ESSAYS, AND REVIEWS. [xii. 



upon himself the obvious question, how, then, do plants, which 

 cannot be said to have wants or actions, become modified ? To 

 this he replies, that they are modified by the changes in their 

 nutritive processes, which are effected by changing circum 

 stances; and it does not seem to have occurred to him that 

 such changes might be as well supposed to take place among 

 animals. 



When we have said that Lamarck felt that mere speculation 

 was not the way to arrive at the origin of species, but that it 

 was necessary, in order to the establishment of any sound theory 

 on the subject, to discover by observation or otherwise, some 

 vera causa, competent to give rise to them ; that he affirmed the 

 true order of classification to coincide with the order of their 

 development one from another ; that he insisted on the necessity 

 of allowing sufficient time, very strongly ; and that all the 

 varieties of instinct and reason were traced back by him to the 

 same cause as that which has given rise to species, we have 

 enumerated his chief contributions to the advance of the 

 question. On the other hand, from his ignorance of any power 

 in Nature competent to modify the structure of animals, except 

 the development of parts, or atrophy of them, in consequence of 

 a change of needs, Lamarck was led to attach infinitely greater 

 weight than it deserves to this agency, and the absurdities into 

 which he was led have met with deserved condemnation. Of 

 the struggle for existence, on which, as, we shall see, Mr. Darwin 

 lays such great stress, he had no conception ; indeed, he doubts 

 whether there really are such things as extinct species, unless 

 they be such large animals as may have met their death at the 

 hands of man ; and so little does he dream of there being any 

 other destructive causes at work, that, in discussing the possible 

 existence of fossil shells, he asks, &quot; Pourquoi d ailleurs seroient- 

 ils perdues des que 1 homme n a pu operer leur destruction ? &quot; 

 (Phil. ZooL, vol. i. p. 77.) Of the influence of selection Lamarck 

 has as little notion, and he makes no use of the wonderful 

 phenomena which are exhibited by domesticated animals, and 

 illustrate its powers. The vast influence of Cuvier was employed 



