Contributions to the theory of natural selection. A series of essays ... By Alfred Russel Wallace ...

Viii PREFACE.
IX, —THE DEVELOPMENT OF HUMAN RACES UNDER
THE LAW OF NATURAL SELECTION.
First published in the "Anthropological Review,"
May, 1864. Now reprinted with a few important alterations and additions. I had intended to have considerably extended this essay, but on attempting it I found
that I should probably weaken the effect without adding much to the argument. I have therefore preferred
to leave it as it was first written, with the exception
of a few ill-considered passages which never fully expressed my meaning. As it now stands, I believe it
contains the enunciation of an important truth.
X.-THE LIMITS OF NATURAL SELECTION AS APPLIED
TO MBAN.
This is the further development of a few sentences
at the end of an article on " Geological Time and the
Origin of Species," which appeared in the "Quarterly
Review," for April, 1869. I have here ventured to
touch on a class of problems which are usually considered to be beyond the boundaries of science, but
which, I believe, will one day be brought within her
domain.
For the convenience of those who are acquainted
with any of my essays in their original form, I subjoin references to the more important additions and
alterations now made to them.