Kala-Azar in the Grey Monkey of the Sudan

parasites were visible in the spleen smears (monkey Ei was success- fully infected from the same case during life).

Monkey C was inoculated with a spleen emulsion from monkey B, but was not infected by the 108th day, when it was chloroformed. Probably, as Nicolle has pointed out, the parasite tends to lose its virulence when inoculated from monkey to monkey, and this might account for the non-infection in this case, though the positive results obtained in monkeys L and N show that infection can be conveyed from monkey to monkey. In the case of monkeys L and N, however, the inoculation was made from a splenic puncture during life, and in the case of monkey C a post-mortem splenic emulsion was used.

Monkey O died 42 days after inoculation. There was no apparent cause of death, and no Leishman bodies were found.

Monkey K, which was inoculated subcutaneously, and which is

still alive, shows definite enlargement of the spleen, but one liver puncture and two spleen punctures have so far given negative results.

The Presence of Parasites in the Peripheral Blood of Infected Monkeys.—Parasites are present in the peripheral blood of infected monkeys, but are difficult to find. In two infected monkeys, still alive, we have searched carefully for parasites in the peripheral blood. In one monkey we found in the fifth slide three parasites inside a large mononuclear cell; in another monkey, out of seven slides examined, we found one parasite inside a polynuclear cell.

Captain Archibald, R.A.M.C., has also successfully infected the red monkey of the Sudan (Cercopithecus ruber) with the disease.

We have tried inoculating dogs, but so far have failed to infect that animal as, with one exception, all the animals died soon after inoculation. We have also not yet met with spontaneous Leish- maniosis in the dog.

In the Sudan form of kala-azar the parasite is present in the peripheral blood in over 20 per cent of the infected people. The parasite morphologically resembles that of Indian kala-azar and infantile kala-azar; growth into flagellate forms has been obtained in 10 per cent. citrate, on Novy and MacNeal’s medium, and on Nicolle’s modification of that medium. Full details of these inves- tigations will appear in the reports of the Wellcome Tropical Research Laboratories at Khartoum.

CONCLUSIONS.

(1) The ordinary grey monkey of the Sudan, Cercopithecus sabeus, can be infected with kala-azar.