7* VARIATIONS, DUE TO REVERSION. 



new characters, and the reappearance of long-lost 

 characters evoked through the act of crossing." 



Darwin in Chap, xxivth, of his Animals and Plants, 

 &c, reviews all of the conditions of development, viz., 

 food, exercise, climate, crossing, &c, which divers 

 authors have ignorantly regarded as the causes of 

 variability ; and he says (p. 303, Vol. ii) : 



" But we must, I think, take a broader view, and 

 conclude that organic beings, when subjected during 

 several generations to any change whatever in their 

 conditions, ' tend (!) to vary ; the kind of variation, 

 which ensues, depending in a far higher degree on the 

 nature or constitution (!) of the being, than on the 

 nature of the changed conditions." 



On the preceding page, he says : 



" The subject (2. e., of " the causes of the almost 

 universal variability of our domesticated productions") 

 " is an obscure one ; but it may be useful to probe our 

 ignorance." 



With him, the obscurity arises from this : That he 

 finds it " impossible* to distinguish between the reap- 

 pearance of ancient characters, and the first appearance 

 of "new characters," because, the characters which 

 arise are all " ancient characters." 



He says that variation may be accounted for, 



" By the more or less complete recovery, through 

 reversion, of ancestral characters on either side ; but 

 we thus only push the difficulty further back in time, 

 for what made the parents, or their progenitors differ- 

 ent?" 



If the explanation by means of Reversion, only 

 pushes the difficulty further back in time, why does 



