12 THE DARWINIAN HYPOTHESIS r 



the attempt to gratify such desires will result in an 

 appropriate modification of the organs exerted. 

 Make a man a blacksmith, and his brachial muscles 

 will develop in accordance with the demands made 

 upon them, and in like manner, says Lamarck, 

 &quot; the efforts of some short-necked bird to catch 

 fish without wetting himself have, with time and 

 perseverance, given rise to all our herons and 

 long-necked waders.&quot; 



The Lamarckian hypothesis has long since been 

 justly condemned, and it is the established prac 

 tice for every tyro to raise his heel against the 

 carcase of the dead lion. But it is rarely either 

 wise or instructive to treat even the errors of a 

 really great man with mere ridicule, and in the 

 present case the logical form of the doctrine stands 

 on a very different footing from its substance. 



If species have really arisen by the operation 

 of natural conditions, we ought to be able to find 

 those conditions now at work ; we ought to be 

 able to discover in nature some power adequate 

 to modify any given kind of animal or plant in 

 such a manner as to give rise to another kind, 

 which would be admitted by naturalists as a 

 distinct species. Lamarck imagined that he had 

 discovered this vera causa in the admitted facts 

 that some organs may be modified by exercise ; 

 and that modifications, once produced, are capable 

 of hereditary transmission. It does not seem to 

 have occurred to him to inquire whether there is 



