58 BOOK OF NATURE LAID OPEN. 



where they are suffered to mix together, the de- 

 scendants of an animal of one of these varieties is 

 very different from that of the parent race. This 

 fact having been remarked, has given rise to an opi- 

 nion, that there has been originally but one pair of 

 animals of each species, and that all the varieties we 

 now discover of the same species, have been pro- 

 duced by accidental circumstances only, such as a 

 variation of climate, of food, or of some other ex- 

 traneous peculiarity ; and that, of course, one va- 

 riety may. be transmuted into another without any 

 intermixture of blood, purely by a change of cir- 

 cumstances only. This doctrine being once ad- 

 mitted, the inferences which necessarily result from 

 it, have proved highly detrimental to the practice 

 of individuals in their attempts to improve the breed 

 of domestic animals ; as it tends, in as far as that 

 doctrine is believed, to turn the attention of men 

 from fixed and certain principles, which admit of no 

 variation, to others that are vague and erroneous, 

 which tend only to puzzle and confound the mind, 

 and leave it in perpetual darkness and uncertainty. 



The boldest asserter of the doctrine, that all the 

 varieties of every species of animal are derived from 

 one common stock, is the celebrated Buffon, who, 

 instead of searching for proofs to support his hypo- 

 thesis, contents himself with mere assertions, uttered 

 with as much confidence as if the matter had been 

 before proved beyond a possibility of doubt; and 

 he takes as the subject for his illustration the dog 

 kind, though the varieties of this species are more 



