ously written two condensed sketches, and to his having
finally made an abstract of a much larger manuscript, which itself was
an abstract. By this winnowing process he had been enabled to select the
more striking facts and conclusions. As to the current assertion that
the "Origin" succeeded because the subject was in the air, or because
men's minds were prepared for it, Darwin was disposed to doubt whether
this was strictly true. In previous years he had occasionally sounded
not a few naturalists, and had never come across a single one who seemed
to doubt about the permanence of species. Probably men's minds were
prepared in this sense, that innumerable well-verified facts were stored
away in the memories of naturalists, ready to take their proper places
as soon as any theory which would account for them should be strongly
supported. Darwin himself thought that he gained much by a delay in
publishing, from about 1839, when the "Darwinian" theory was clearly
conceived, to 1859; and that he lost nothing, because he cared very
little whether men attributed most originality to him or to Wallace.

Darwin's "Variation of Animals and Plants under Domestication" was begun
in 1860, but was not published till 1868. The book was a big one, and
cost him four years and two months' hard labor. It gives in the first
volume all his personal observations, and an immense number of facts,
collected from various sources, about domestic productions, animal and
vegetable. In the second volume the causes and laws of variation,
inheritance, etc., are discussed. Towards the end of the work is
propounded the hypothesis of Pangenesis, which has been generally
rejected, and which the author himself looked upon as unverified,
although by it a remarkable number of isolated facts could be connected
together and rendered intelligible.

The "Descent of Man" was published in February, 1871. Touching this
work, Darwin has told us that, as soon as he had become (in 1837 or
1838) convinced that species were mutable productions, he could not
avoid the belief that man must come under the same law. Accordingly, he
collected notes on the subject for his own satisfaction, and not for a
long time with any intention of publishing. In the "Origin of Species,"
the derivation of any particular species is never discussed; but in
order that no honorable man should accuse him of concealing his views,
Darwin had thought it best to add that by that work, "light would be