86 VARIATIONS, DUE TO REVERSION. 



conditions, vary in different manners, whilst closely 

 allied organisms under dissimilar conditions, often 

 vary in nearly the same manner. We see this in 

 the same modification frequently reappearing at long 

 intervals of time in the same variety, and likewise 

 in the several striking cases given of analogous or 

 parallel varieties. Although some of these latter cases 

 are simply due to reversion, others cannot thus be 

 accounted for." 



The only reason he can advance, for urging that 

 some positive variations "cannot thus be accounted 

 for," is, that he does not know of any individuals of 

 the species under nature, in which the characters 

 which arise, are to be seen. It is clear that, if de- 

 generation has been so rife under nature, then, this 

 objection cannot obtain. 



On page 307 (Vol. ii, Animals and Plants, &c), he 

 says: 



" Bud-variation, which we fully discussed in a former 

 chapter, shows us that variability may be quite inde- 

 pendent of seminal reproduction, and likewise a rever- 

 sion to long-lost ancestral characters." 



In this former chapter, to which he alludes, he says* 

 (p. 449, Vol. i, Animals and Plants, &c): 



" Nor can we account, in all cases, for the appear- 

 ance, through bud-variation, of new characters, by the 

 principle of reversion to long-lost characters." 



Darwin's inability to account, by reversion, for some 



■>f the variations, is due to his idea that varietal types 



xi thus to be explained. It is not the types, which 



1 be explained by reversion; but those positive 



