ii DARWIN'S HYPOTHESIS. 149 



Now, Mr. Darwin's hypothesis is not, so far as 

 I am aware, inconsistent with any known biological 

 fact; on the contrary, if admitted, the facts of De- 

 velopment, of Comparative Anatomy, of Geo- 

 graphical Distribution, and of Palaeontology, be- 

 come connected together, and exhibit a meaning 

 such as they never possessed before; and I, for 

 one, am fully convinced, that if not precisely 

 true, that hypothesis is as near an approxima- 

 tion to the truth as, for example, the Copernican 

 hypothesis was to the true theory of the planetary 

 motions. 



But, for all this, our acceptance of the Dar- 

 winian hypothesis must be provisional so long as 

 one link in the chain of evidence is wanting; and 

 so long as all the animals and plants certainly pro- 

 duced by selective breeding from a common stock 

 are fertile, and their progeny are fertile with one 

 another, that link will be wanting. For, so long, 

 selective breeding will not be proved to be com- 

 petent to do all that is required of it to produce 

 natural species. 



I have put this conclusion as strongly as 

 possible before the reader, because the last posi- 

 tion in which I wish to find myself is that of an 

 advocate for Mr. Darwin's, or any other views; if 

 by an advocate is meant one whose business it is 

 to smooth over real difficulties, and to persuade 

 where he cannot convince. 



In justice to Mr. Darwin, however, it must be 



