1870— 1882] NATURAL SELECTION 387 



If I think continuously on some half-dozen structures of Letter 299 

 which we can at present see no use, I can persuade myself 

 that Natural Selection is of quite subordinate importance. 

 On the other hand, when I reflect on the innumerable struc- 

 tures, especially in plants, which twenty years ago would have 

 been called simply " morphological " and useless, and which 

 are now known to be highly important, I can persuade myself 

 that every structure may have been developed through 

 Natural Selection. It is really curious how many out of a 

 list of structures which Bronn enumerated, as not possibly due 

 to Natural Selection because of no functional importance, can 

 now be shown to be highly important. Lobed leaves was, I 

 believe, one case, and only two or three days ago Frank 

 showed me how they act in a manner quite sufficiently im- 

 portant to account for the lobing of any large leaf. I am 

 particularly delighted at what you say about domestic dogs, 

 jackals, and wolves, because from mere indirect evidence I 

 arrived in Varieties of Domestic Animals at exactly the same 

 conclusion x with respect to the domestic dogs of Europe and 

 North America. See how important in another way this 

 conclusion is ; for no one can doubt that large and small dogs 

 are perfectly fertile together, and produce fertile mongrels ; 

 and how well this supports the Pallasian doctrine 2 that domes- 

 tication eliminates the sterility almost universal between forms 

 slowly developed in a state of nature. 



I humbly beg your pardon for bothering you with so long 

 a note ; but it is your own fault. 



Plants are splendid for making one believe in Natural 

 Selection, as will and consciousness are excluded. I have 

 lately been experimenting on such a curious structure for 

 bursting open the seed-coats : I declare one might as well 

 say that a pair of scissors or nutcrackers had been developed 

 through external conditions as the structure in question. 3 



1 Mr. Darwin's view was that domestic dogs descend from more than 

 one wild species. 



2 See Letter 80. 



3 The peg or heel in Cucurbila : see Power of Movement in Plants 

 p. 102. 



