HYBRIDISM 249 



attempts to express all kinds of resemblance between 

 all species. 



First crosses between forms known to be varieties, or 

 sufficiently alike to be considered as varieties, and their 

 mongrel offspring, are very generally, but not quite 

 universally, fertile. Nor is this nearly general and 

 perfect fertility surprising, when we remember how 

 liable we are to argue in a circle with respect to varieties 

 in a state of nature ; and when we remember that the 

 greater number of varieties have been produced under 

 domestication by the selection of mere external differ- 

 ences, and not of differences in the reproductive system. 

 In all other respects, excluding fertility, there is a close 

 general resemblance between hybrids and mongrels. 

 Finally, then, the facts briefly given in this chapter do 

 not seem to me opposed to, but even rather to support 

 the view, that there is no fundamental distinction 

 between species and varieties. 



