interest in studying the origin of the human body, with which he is
daily occupied. But I must not give here this special description of
the embryonic processes such as it has hitherto been given, as most of
my readers have not studied anatomy, and are not likely to be
entrusted with the care of the adult organism. I must content myself
with giving some parts of the subject only in general outline, and
must not enter upon all the marvellous, but very intricate and not
easily described, details that are found in the story of the
development of the human frame. To understand these fully a knowledge
of anatomy is needed. I will endeavour to be as plain as possible in
dealing with this branch of science. Indeed, a sufficient general idea
of the course of the embryonic development of man can be obtained
without going too closely into the anatomic details. I trust we may be
able to arouse the same interest in this delicate field of inquiry as
has been excited already in other branches of science; though we shall
meet more obstacles here than elsewhere.

The story of the evolution of man, as it has hitherto been expounded
to medical students, has usually been confined to embryology--more
correctly, ontogeny--or the science of the development of the
individual human organism. But this is really only the first part of
our task, the first half of the story of the evolution of man in that
wider sense in which we understand it here. We must add as the second
half--as another and not less important and interesting branch of the
science of the evolution of the human stem--phylogeny: this may be
described as the science of the evolution of the various animal forms
from which the human organism has been developed in the course of
countless ages. Everybody now knows of the great scientific activity
that was occasioned by the publication of Darwin's Origin of Species
in 1859. The chief direct consequence of this publication was to