ve pages; and this was
enlarged during the summer of 1844 into one of two hundred thirty 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
on; and I can remember the very spot in the road, while riding in my
carriage, that, 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 fully, and I began
at once to do so on a scale three or four times as extensive as that
which was afterward 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 Alfred Russel 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. 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 manuscript, together with a
letter to Asa Gray, dated September 5, 1857, to be published at the same
time with Wallace's essay, are given in the _Journal of the Proceedings
of the Linnean Society_, 1858. I was at first very unwilling to consent,
as I thought Mr. Wallace might consider my doing so unjustifiable, for I
did not then know how generous and noble was his disposition. Neither
the extract from my manuscript nor the letter to Gray had been intended
for publication, and they were badly written. Mr. Wallace's essay, on
the other hand, was admirably expressed and quite clear. Nevertheless,
our joint productions excited very little attention, and