Naulette in Belgium, and at Malarnaud
in France, increase our material which is now as abundant as could be
desired. The most recent discovery of all is that of a skull dug up in
August of this year [1908] by Klaatsch and Hauser in the lower grotto
of the Le Moustier in Southern France, but this skull has not yet been
fully described. Thus _Homo primigenius_ must also be regarded as
occupying a position in the gap existing between the highest apes and
the lowest human races, _Pithecanthropus_, standing in the lower part
of it, and _Homo primigenius_ in the higher, near man. In order to
prevent misunderstanding, I should like here to emphasise that in
arranging this structural series--anthropoid apes, _Pithecanthropus_,
_Homo primigenius_, _Homo sapiens_--I have no intention of
establishing it as a direct genealogical series. I shall have
something to say in regard to the genetic relations of these forms,
one to another, when discussing the different theories of descent
current at the present day.[118]

In quite a different domain from that of morphological relationship,
namely in the physiological study of the blood, results have recently
been gained which are of the highest importance to the doctrine of
descent. Uhlenhuth, Nuttall, and others have established the fact that
the blood-serum of a rabbit which has previously had human blood
injected into it, forms a precipitate with human blood. This
biological reaction was tried with a great variety of mammalian
species, and it was found that those far removed from man gave no
precipitate under these conditions. 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