84 AUTOBIOGRAPHY. 



some time to write even the briefest sketch of it. In 

 June 1842 I first allowed myself the satisfaction of 

 writing a very brief abstract of my theory in pencil in 

 35 pages ; and this was enlarged during the summer of 

 1844 into one of 230 pages, which I had fairly copied 

 out and still possess. 



But at that time I overlooked one problem of great 

 importance ; and it is astonishing to me, except on the 

 principle of Columbus and his egg, how I could have 

 overlooked it and its solution. This problem is the 

 tendency in organic beings descended from the same 

 stock to diverge in character as they become modified. 

 That they have diverged greatly is obvious from the 

 manner in which species of all kinds can be classed 

 under genera, genera under families, families under 

 sub-orders and so forth ; and I can remember the 

 very spot in the road, whilst in my carriage, when to 

 my joy the solution occurred to me ; and this was 

 long after I had come to Down. The solution, as I 

 believe, is that the modified offspring of all dominant 

 and increasing forms tend to become adapted to 

 many and highly diversified places in the economy of 

 nature. 



Early in 1856 Lyell advised me to write out my 

 views pretty fully, and I began at once to do so on a 

 scale three or four times as extensive as that which 

 was afterwards followed in my ' Origin of Species ; ' 

 yet it was only an abstract of the materials which I 

 had collected, and I got through about half the work 

 on this scale. But my plans were overthrown, for 

 early in the summer of 1858 Mr. Wallace, who was 



