l selection has played in the history
of man, want scientific precision." ("Descent of Man", page 924.) I
need here only point out that it is impossible to explain the graduated
stages of skin-colour by sexual selection, since it would have produced
races sharply defined by their colour and not united to other races
by transition stages, and this, it is well known, is not the case.
Moreover, the fact established by me ("Die Hautfarbe des Menschen",
"Mitteilungen der Anthropologischen Gesellschaft in Wien", Vol. XXXIV.
pages 331-352.), that in all races the ventral side of the trunk is
paler than the dorsal side, and the inner surface of the extremities
paler than the outer side, cannot be explained by sexual selection in
the Darwinian sense.

With this I conclude my brief survey of the rich contents of Darwin's
book. I may be permitted to conclude by quoting the magnificent final
words of "The Descent of Man": "We must, however, acknowledge, as it
seems to me, that man, with all his noble qualities, with sympathy which
feels for the most debased, with benevolence which extends not only
to other men but to the humblest living creature, with his god-like
intellect which has penetrated into the movements and constitution of
the solar system--with all these exalted powers--Man still bears in his
bodily frame the indelible stamp of his lowly origin." (Ibid. page 947.)

What has been the fate of Darwin's doctrines since his great
achievement? How have they been received and followed up by the
scientific and lay world? And what do the successors of the mighty hero
and genius think now in regard to the origin of the human race?

At the present time we are incomparably more favourably placed than
Darwin was for answering this question of all questions. We have at our
command an incomparably greater wealth of material than he had at his
disposal. And we are more fortunate than he in this respect, that we
now know transition-forms which help to fill up the gap, still great,
between the lowest human races and the highest apes. Let us consider
for a little the more essential additions to our knowledge since the
publication of "The Descent of Man".

Since that time our knowledge of animal embryos has increased
enormously. While Darwin was obliged to content himself with comparing
a human embryo with that of a dog, there are now available the youngest
embryos of monkeys of all possible groups (Orang, Gibbon, Semnopithecus,
Macacus