Art and Science 



let in the thin end of the wedge, as Mr. 

 Darwin did when he said that use and disuse 

 did a good deal towards modification. Buffon, 

 in his first volume on the lower animals, 1 

 dwells on the impossibility of stopping the 

 breach once made by admission of variation 

 at all. " If the point," he writes, " were once 

 gained, that among animals and vegetables 

 there had been, I do not say several species, 

 but even a single one, which had been pro- 

 duced in the course of direct descent from 

 another species ; if, for example, it could be 

 once shown that the ass was but a degenera- 

 tion from the horse then there is no farther 

 limit to be set to the power of Nature, and 

 we should not be wrong in supposing that 

 with sufficient time she could have evolved 

 all other organised forms from one primordial 

 type." So with use and disuse and trans- 

 mission of acquired characteristics generally 

 once show that a single structure or instinct 

 is due to habit in preceding generations, and 

 we can impose no limit on the results achiev- 

 able by accumulation in this respect, nor 



1 Tom. iv. p. 383. Ed. 1753. 

 303 



