would tend to be preserved, and unfavourable ones
to be destroyed. The result of this would be the formation of new
species. Here then I had at last got a theory by which to work."

{12} _Life and Letters_, i. p. 83.

It is surprising that Malthus should have been needed to give him the
clue, when in the Note Book of 1837 there should occur--however
obscurely expressed--the following forecast{13} of the importance of the
survival of the fittest. "With respect to extinction, we can easily see
that a variety of the ostrich (Petise{14}), may not be well adapted, and
thus perish out; or on the other hand, like Orpheus{15}, being
favourable, many might be produced. This requires the principle that the
permanent variations produced by confined breeding and changing
circumstances are continued and produce<d> according to the adaptation of
such circumstances, and therefore that death of species is a consequence
(contrary to what would appear in America) of non-adaptation of
circumstances."

{13} _Life and Letters_, ii. p. 8.

{14} Avestruz Petise, _i.e. Rhea Darwini_.

{15} A bird.

I can hardly doubt, that with his knowledge of the interdependence of
organisms and the tyranny of conditions, his experience would have
crystallized out into "a theory by which to work" even without the aid
of Malthus.

In my father's Autobiography{16} he writes, "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{17}, which I had fairly copied out and still
possess." These two Essays, of 1842 and 1844, are now printed under the
title _The Foundations of the Origin of Species_.

{16} _Life and Letters_, i. p. 84.

{17} It contains as a fact 231 pp. It is a strongly bound folio,
interleaved with blank pages, as though for notes and additions.
His own MS. from which it was copied contains 189 pp.

It will be noted that in the above passage he does not mention the MS.
of 1842 as being in existence, and when I was at work on _Life and
Letters_ I had not seen it. It only came to light after my mother's
death in 1896 when the house at Down was vacated. The MS. was hidden in
a cupboard under the stairs which was not used for papers of any value,
but rather as an overflow for matter which he did not wish to destroy.

The statement in the Autobiography that the MS.