f Species" is so far from prominent
and so incidental that it was excusable to assume that Darwin had not
touched upon the descent of man in this work. It was solely the desire
to have his mass of evidence sufficiently complete, solely Darwin's
great characteristic of never publishing till he had carefully weighed
all aspects of his subject for years, solely, in short, his most
fastidious scientific conscience that restrained him from challenging
the world in 1859 with a book in which the theory of the descent of man
was fully set forth. Three years, frequently interrupted by ill-health,
were needed for the actual writing of the book ("Life and Letters", Vol.
I. page 94.): the first edition, which appeared in 1871, was followed in
1874 by a much improved second edition, the preparation of which he very
reluctantly undertook. (Ibid. Vol. III. page 175.)

This, briefly, is the history of the work, which, with the "Origin of
Species", marks an epoch in the history of biological sciences--the work
with which the cautious, peace-loving investigator ventured forth from
his contemplative life into the arena of strife and unrest, and
laid himself open to all the annoyances that deep-rooted belief and
prejudice, and the prevailing tendency of scientific thought at the time
could devise.

Darwin did not take this step lightly. Of great interest in this
connection is a letter written to Wallace on Dec. 22, 1857 (Ibid. Vol.
II. page 109.), in which he says "You ask whether I shall discuss
'man.' I think I shall avoid the whole subject, as so surrounded
with prejudices; though I fully admit that it is the highest and most
interesting problem for the naturalist." But his conscientiousness
compelled him to state briefly his opinion on the subject in the "Origin
of Species" in 1859. Nevertheless he did not escape reproaches for
having been so reticent. This is unmistakably apparent from a letter to
Fritz Muller dated February 22 (1869?), in which he says: "I am thinking
of writing a little essay on the Origin of Mankind, as I have been
taunted with concealing my opinions." (Ibid. Vol. III. page 112.)

It might be thought that Darwin behaved thus hesitatingly, and was so
slow in deciding on the full publication of his collected material in
regard to the descent of man, because he had religious difficulties to
overcome.

But this was not the case, as we can see from his admirable confession
of faith, the publication of which we owe t