v MR. DARWIN'S CRITICS 181 



lent example of this class of difficulties is to be 

 found in Mr. Mivart's chapter on " Independent 

 Similarities of Structure." Mr. Mivart says that 

 these cannot be explained by an " absolute and 

 pure Darwinian," but " that an innate power and 

 evolutionary law, aided by the corrective action 

 of natural selection, should have furnished like 

 needs with like aids, is not at all improbable " 

 (p. 82). 



I do not exactly know what Mr. Mivart means 

 by an " absolute and pure Darwinian ; " indeed 

 Mr. Mivart makes that creature hold so many 

 singular opinions that I doubt if I can ever have 

 seen one alive. But I find nothing in his 

 statement of the view which he imagines to be 

 originated by himself, which is really inconsistent 

 with what I understand to be Mr. Darwin's views. 



I apprehend that the foundation of the theory 

 of natural selection is the fact that living bodies 

 tend incessantly to vary. This variation is neither 

 indefinite, nor fortuitous, nor does it take place in 

 all directions, in the strict sense of these words. 



Accurately speaking, it is not indefinite, nor 

 does it take place in all directions, because it is 

 limited by the general characters of the type to 

 which the organism exhibiting the variation 

 belongs. A whale does not tend to vary in the 

 direction of producing feathers, nor a bird in the 

 direction of developing whalebone. In popular 

 language there is no harm in saying that the 



