human blood- serum. If allowed to rest, the precipitated substance gravitates to the bottom of the tube. I have now tested upwards of 230 bloods obtained from animals of all classes of vertebrates with such anti-serum for human blood, and have, with the single exception of monkey bloods, obtained negative results throughout. Similarly, if rabbits are treated with the blood of the horse, dog, ox, sheep, &c., anti-sera are formed which produce precipitations only in the bloods of the animals whose blood was used for treatment, or, to a lesser extent, in the bloods of nearly allied animals.
The importance of the test from a medico-legal standpoint has been fully realised, and we can safely look forward to the test being put to practical use in the detection of crime. Whilst Uhlenhuth has proved that dried blood-stains can be used for the test, a solution of the dried blood being made for the purpose, I have shown that human blood which had putrefied for two months is capable of giving a reaction with its homologous anti-serum. I have, moreover, shown that human blood can be detected in a mixture of five or six different bloods brought into solution so that each blood is present but in the quantity of 1 : 500 or 1 : 600.
As stated above, the only bloods which gave a reaction similar to that of human bloods have been the bloods of different species of monkeys. Since nay papers appeared I have had occasion to test eighteen kinds of monkey bloods. The reaction obtained with monkey blood only differs from that obtained with that of the human subject in degree. Monkey blood gives a feebler reaction than human blood with the anti-serum for human blood.
Accepting the classification of the Primates given by Flower and Lydekker,* we find that they are classified into two groups, the Lemuroidea (Lemurs) and Anthropoidea (Man and the Apes). As stated by the authors named, the view that the Lemurs belong to the Primates is largely traditional ; they think they should, perhaps, be grouped in a distinct order. There are facts for and against this. Taking the Anthropoidea, we find them divided into the five families, Hapalidae, Cebidse (New World Apes), Cercopithecidse, Simiidse (Old World Apes), and Hominidse (Man). According to Darwin, the Old World apes are more closely related in many respects to the Hominidse than are the New World apes. And it is a striking fact, brought out by the tests I have made, that the New World monkeys give a less marked reaction with the anti-serum for human blood than do the Old World monkeys. On the other hand, the test gave a negative result when applied to the blood of two species of lemur (L. xanthomystax, L. ntfifrons).
The eighteen monkey bloods tested were as follows : Hapalidae (Hapale pygmcea, Midas cedipus), Cebidae (Mycetes seniculus, Uacaria
- ' Mammals, Living and Extinct,' 1891.
