epared to appreciate the struggle for existence which
everywhere goes on from long-continued observation of the habits of
animals and plants, it at once struck me that under these circumstances
favourable variations would tend to be preserved and unfavourable ones
to be destroyed. The result of this would be the formation of a new
species. Here then I had at last got a theory by which to work; but I
was so anxious to avoid prejudice that I determined not for 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 on 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. This 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 then in the Malay
Archipelago, sent me an essay "On the tendency of varieties to depart
indefinitely from the original type;" and this essay contained exactly
the same theory as mine.[3] Mr. Wallace expressed the wish that if I
thought well of his essay I should send it to Lyell for perusal.

The circumstances under which I consented at the request of Lyell and
Hooker to allow of an abstract from my MS., together with a letter to
Asa Gray, dated Septe