in the case of other animals. When I had explained this pregnant fact
and its significance in my History of Creation, it was described in
many of the theological journals as a dishonest invention of my own.
The fact that the embryos of man and the dog are, at a certain stage
of their development, almost indistinguishable was also denied. When
we examine the human embryo in the third or fourth week of its
development, we find it to be quite different in shape and structure
from the full-grown human being, but almost identical with that of the
ape, the dog, the rabbit, and other mammals, at the same stage of
ontogeny. We find a bean-shaped body of very simple construction, with
a tail below and a pair of fins at the sides, something like those of
a fish, but very different from the limbs of man and the mammals.
Nearly the whole front half of the body is taken up by a shapeless
head without face, at the sides of which we find gill-clefts and
arches as in the fish. At this stage of its development the human
embryo does not differ in any essential detail from that of the ape,
dog, horse, ox, etc., at a corresponding period. This important fact
can easily be verified at any moment by a comparison of the embryos of
man, the dog, rabbit, etc. Nevertheless, the theologians and dualist
philosophers pronounced it to be a materialistic invention; even
scientists, to whom the facts should be known, have sought to deny
them.

There could not be a clearer proof of the profound importance of these
embryological facts in favour of the monistic philosophy than is
afforded by these efforts of its opponents to get rid of them by
silence or denial. The truth is that these facts are most inconvenient
for them, and are quite irreconcilable with their views. We must be
all the more pressing on our side to put them in their proper light. I
fully agree with Huxley when he says, in his "Man's Place in Nature":