468 THE CAUSES OF THE XI 



strong and muscular ; such organic modification is 

 a result of this particular action and exercise. 

 Lamarck thought that by a very simple supposi- 

 tion based on this truth he could explain the origin 

 of the various animal species : he said, for ex- 

 ample, that the short-legged birds which live on 

 fish had been converted into the long-legged 

 waders by desiring to get the fish without wetting 

 their feathers, and so stretching their legs more 

 and more through successive generations. If 

 Lamarck could have shown experimentally that 

 even races of animals could be produced in this 

 way, there might have been some ground for his 

 speculations. But he could show nothing of the 

 kind, and his hypothesis has pretty well dropped 

 into oblivion, as it deserved to do. I said in an 

 earlier lecture that there are hypotheses and hy- 

 potheses, and when people tell you that Mr. Dar- 

 win's strongly-based hypothesis is nothing but a 

 mere modification of Lamarck's, you will know 

 what to think of their capacity for forming a 

 judgment on this subject. 



But you must recollect that when I say I think 

 it is either Mr. Darwin's hypothesis or nothing ; 

 that either we must take his view, or look upon 

 the whole of organic nature as an enigma, the 

 meaning of which is wholly hidden from us ; you 

 must understand that I mean that I accept it 

 provisionally, in exactly the same way as 1 accept 

 any other hypothesis. Men of science do not 



