CHARACTERS OF SPECIliS AND VARIETIES. 23 



from one another, as having existed in nearly the same form 

 since their iirst creation. 



15. The Naturalist, then, regards as distinct species those 

 races of Plants, the differences between which are evident, and 

 are such as are not likely to have resulted from cultivation or 

 any other external cause, and do not exhibit any tendency to 

 alteration in progress of years. Such, for example, are those 

 between the Apple and Pear among Plants, or the Dog and the 

 Fox among animals. Among all the varieties of the Apple, dif- 

 ferent as they are from one another, there is none which exhibits 

 any close resemblance to the Pear ; and of all the kinds of Pear, 

 there is none which so far loses its distinguishing characters, as 

 to show any great similarity to the Apple. And yet among the 

 varieties of the latter, there are kinds which are more different 

 from each other in size, shape, colour, flavour, &c., than some of 

 these are from the Pear ; but while all these show a marked 

 tendency to change under different circumstances of growth, the 

 internal differences between the Apple and Pear never exhibit 

 any such tendency, but remain constant through all the varieties 

 of each. The same may be said of the Dog and the Fox ; for, 

 though some varieties or breeds of the former seem to differ from 

 each other more than they do from the Fox, yet these differ- 

 ences are liable to disappear altogether when the animals return 

 to a wild state, all merging in a form most nearly resembling 

 that of the Shepherd's dog; whilst the differences between the 

 Fox, and the breeds of Dog most nearly allied to it, are con- 

 stantly manifested. 



1 6. On the other hand, the Naturalist regards as, varieties of 

 the same species, those Plants and Animals, in the various speci- 

 mens of which, however dissimilar they may be, the points of 

 difference exhibit such a tendency to variation, that the one kind 

 passes, as it were, into the other. Thus, the Grayhound and 

 the Bull-Dog would be regarded as springing from originally 

 different stocks, if we did not meet with intermediate forms of 

 the Dog, which blend the peculiar characters of both. And the 

 Primrose, Cowslip, and Polyanthus have been regarded as dis- 

 tinct species, so considerable are their differences in form and 



