be intended, "to variations in no way connected with use and
disuse," as not being assignable to any known cause of general
application, and referable as far as we are concerned to accident
only; so that he gives the natural survival of the luckiest, which
is indeed his distinctive feature, if it deserve to be called a
feature at all, greater prominence than ever. Nevertheless there is
no change in his concluding paragraph, which still remains an
embodiment of the views of Erasmus Darwin and Lamarck.

The other passage is on p. 421 of the edition of 1876. It stands:-
"I have now recapitulated the facts and considerations which have
thoroughly" (why "thoroughly"?) "convinced me that species have been
modified during a long course of descent. This has been effected
chiefly through the natural selection of numerous, successive,
slight, favourable variations; aided in an important manner by the
inherited effects of the use and disuse of parts; and in an
unimportant manner, that is, in relation to adaptive structures,
whether past or present, by the direct action of external
conditions, and by variations which seem to us in our ignorance to
arise spontaneously. It appears that I formerly underrated the
frequency and value of these latter forms of variation as leading to
permanent modifications of structure independently of natural
selection."

Here, again, it is not use and disuse which Mr. Darwin declares
himself to have undervalued, but spontaneous variations. The
sentence just given is one of the most confusing I ever read even in
the works of Mr Darwin. It is the essence of his theory that the
"numerous successive, slight, favourable variations," above referred
to, should be fortuitous, accidental, spontaneous; it is evident,