122 THE WRITING OF THE 'ORIGIN OF SPECIES.' [1858. 



graphical distribution of organic beings. In regard to my 

 Abstract, you must take immensely on trust, each paragraph 

 occupying one or two chapters in my book. You will, 

 perhaps, think it paltry in me, when I ask you not to mention 

 my doctrine ; the reason is, if any one, like the author of the 

 ' Vestiges/ were to hear of them, he might easily work them 

 in, and then I should have to quote from a work perhaps 

 despised by naturalists, and this would greatly injure any 

 chance of my views being received by those alone whose 

 opinions I value. [Here follows a discussion on " large 

 genera varying," which has no direct connection with the 

 remainder of the letter.] 



I. It is wonderful what the principle of Selection by Man, 

 that is the picking out of individuals with any desired quality, 

 and breeding from them, and again picking out, can do. 

 Even breeders have been astonished at their own results. 

 They can act on differences inappreciable to an uneducated 

 eye. Selection has been methodically followed in Europe for 

 only the last half century. But it has occasionally, and even 

 in some degree methodically, been followed in the most 

 ancient times. There must have been also a kind of uncon- 

 scious selection from the most ancient times, namely, in the 

 preservation of the individual animals (without any thought of 

 their offspring) most useful to each race of man in his par- 

 ticular circumstances. The "roguing," as nursery-men call the 

 destroying of varieties, which depart from their type, is a kind 

 of selection. I am convinced that intentional and occasional 

 selection has been the main agent in making our domestic 

 races. But, however this may be, its great power of modifi- 

 cation has been indisputably shown in late times. Selection 

 acts only by the accumulation of very slight or greater 

 variations, caused by external conditions, or by the mere 

 fact that in generation the child is not absolutely similar to 

 its parent. Man, by this power of accumulating variations,, 

 adapts living beings to his wants he may be said to make 



