88 AUTOBIOGRAPHY. 



of the book was its moderate size ; and this I owe to 

 the appearance of Mr. Wallace's essay ; had I pub- 

 lished on the scale in which I began to write in 1856, 

 the book would have been four or five times as large 

 as the ' Origin,' and very few would have had the 

 patience to read it. 



I gained much by my delay in publishing from 

 about 1839, when the theory was clearly conceived, to 

 1859 ; and I lost nothing by it, for I cared very little 

 whether men attributed most originality to me or 

 Wallace ; and his essay no doubt aided in the reception 

 of the theory. I was forestalled in only one important 

 point, which my vanity has always made me regret, 

 namely, the explanation by means of the Glacial 

 period of the presence of the same species of plants 

 and of some few animals on distant mountain summits 

 and in the arctic regions. This view pleased me so 

 much that I wrote it out in extenso, and I believe that 

 it was read by Hooker some years before E. Forbes 

 published his celebrated memoir* on the subject. In 

 the very few points in which we differed, I still think 

 that I was in the right. I have never, of course, 

 alluded in print to my having independently worked 

 out this view. 



Hardly any point gave me so much satisfaction 

 when I was at work on the ' Origin/ as the explana- 

 tion of the wide difference in many classes between 

 the embryo and the adult animal, and of the close 

 resemblance of the embryos within the same class. 

 No notice of this point was taken, as far as I re- 



* ' Geolog. Survey Mem./ 1846. 



