164 EVOLUTION, OLD AND NEW. 



" dans chaque famille, ou si Ion vent, dans chacun des 

 genres" We are told in the next paragraph, that if we 

 choose to look at the matter in this light, well in that 

 case we ought to see not only the ass and the horse, 

 but the zebra too, as members of the same family; 

 "the number of their points of resemblance being 

 infinitely greater than those in respect of which they 

 differ." * Thus, at the close of his work on the qua- 

 drupeds, he thinks it well, as at the commencement 

 seventeen years earlier, to emphasize in his own quiet 

 way his perception that the principles on which he has 

 been insisting should be carried much farther than he 

 has chosen to carry them. 



His conclusion is, that "after comparing all the 

 animals and bringing them each under their proper 

 genus, we shall find the two hundred species we have 

 already described to be reducible into a sufficiently 

 small number of families or main stocks from which it 

 is not impossible that all the others may be derived." t 



The chapter closes thus : 



" To account for the origin of these animals " (cer- 

 tain of those peculiar to America), " we must go back 

 to the time when the two continents were not yet 

 separated, and call to mind the earliest geological 

 changes. At the same time, we must consider the two 

 hundred existing species of quadrupeds as reduced to 

 thirty-eight families. And though this is not at all the 

 state of Nature as she is in our time, and as she has 

 been represented in this volume, and though, in fact, it 

 is a condition which we can only arrive at by induction, 

 * See p. 80 of this volume. f Tom. xiv. p. 358, 1766. 



