itions. But as in other cases among mammals all nearly related forms
yield an almost equally marked precipitate, so the serum of a rabbit
treated with human blood and then added to the blood of an anthropoid
ape gives ALMOST as marked a precipitate as in human blood; the reaction
to the blood of the lower Eastern monkeys is weaker, that to the Western
monkeys weaker still; indeed in this last case there is only a slight
clouding after a considerable time and no actual precipitate. The blood
of the Lemuridae (Nuttall) gives no reaction or an extremely weak one,
that of the other mammals none whatever. We have in this not only a
proof of the literal blood-relationship between man and apes, but the
degree of relationship with the different main groups of apes can be
determined beyond possibility of mistake.

Finally, it must be briefly mentioned that in regard to remains of human
handicraft also, the material at our disposal has greatly increased of
late years, that, as a result of this, the opinions of archaeologists
have undergone many changes, and that, in particular, their views in
regard to the age of the human race have been greatly influenced. There
is a tendency at the present time to refer the origin of man back to
Tertiary times. It is true that no remains of Tertiary man have been
found, but flints have been discovered which, according to the opinion
of most investigators, bear traces either of use, or of very primitive
workmanship. Since Rutot's time, following Mortillet's example,
investigators have called these "eoliths," and they have been traced
back by Verworn to the Miocene of the Auvergne, and by Rutot even to the
upper Oligocene. Although these eoliths are even nowadays the subject of
many different views, the preoccupation with them has kept the problem
of the age of the human race continually before us.

Geology, too, has made great progress since the days of Darwin and
Lyell, and has endeavoured with satisfactory results to arrange the
human remains of the Diluvial period in chronological order (Penck). I
do not intend to enter upon the question of the primitive home of the
human race; since the space at my disposal will not allow of my
touching even very briefly upon all the departments of science which are
concerned in the problem of the descent of man. How Darwin would have
rejoiced over each of the discoveries here briefly outlined! What use
he would have made of the new and precious material, wh