112 DARWINIAFA. 



win's opponents, who argue the immutability of species 

 from the ibises and cats preserved by the ancient 

 Egyptians being just like those of the present day, 

 could triumphantly add a few hundred thousand years 

 more to the length of the experiment and to the 

 force of their argument. 



As the facts stand, it appears that, while some ter- 

 tiary forms are essentially undistinguishable from ex- 

 isting ones, others are the same with a difference, 

 which is judged not to be specific or aboriginal ; and 

 yet others show somewhat greater differences, such as 

 are scientifically expressed by calling them marked 

 varieties, or else doubtful species; while others, dif- 

 fering a little more, are confidently termed distinct, 

 but nearly-related species. Now, is not all this a 

 question of degree, of mere gradation of difference ? 

 And is it at all likely that these several gradations 

 came to be established in two totally different ways — 

 some of them (though naturalists can't agree which) 

 through natural variation, or other secondary cause, 

 and some by original creation, without secondary 

 cause ? We have seen that the judicious Pictet an- 

 swers such questions as Darwin would have him do, 

 in affirming that, in all probability, the nearly-related 

 species of two successive faunas were materially con- 

 nected, and that contemporaneous species, similarly 

 resembling each other, were not all created so, but 

 have become so. This is equivalent to saying that 

 species (using the term as all naturalists do, and must 

 continue to employ the word) have only a relative, 

 not an absolute fixity ; that differences fully equiva- 

 lent to what are held to be specific may arise in the 



