The same observers have ascertained that the large game of the country is a reservoir of the parasite. In view of this, Yorke has advocated as an experimental sanitary measure the extermination of this interesting fauna. Seeing that this terrible disease is spreading, and that it has already crossed the Zambesi, that the range of G. morsitans extends as far south as Zululand, that this species of glossina is not so circumscribed topically as G. palpalis, and that it is believed to be in great measure dependent on these animals, the destruction or driving back of the large game in morsitans countries seems to be the only measure likely to avert what might otherwise prove to be an immense calamity.
Later experiments by Bruce and his, co-workers have shown that T. brucei, when injected into rats, exhibits the same proportion of posterior-nucleated forms as T. rhodesiense. From this and other facts these observers suggest that T. rhodesiense is none other than T. brucei, that 37 per cent, of the wild game in the fly-country harbour pathogenic trypanosomes, and that the waterbuck, hartebeest, reedbuck, and duikerbuck are a source of danger to man.
Taute, who has recently carried out much research work 011 this important subject in Portuguese Nyasaland, does not agree in all respects with the views of Kinghorn, Yorke, and Bruce. He points out that the trypanosomes in naturally infected game or domestic animals can be regarded as a potential cause of sleeping sickness only if they are actually shown to be pathogenic to man; and he maintains that the wild game and domestic animals do not play any part in the spread of sleeping sickness, at all events in the sense of Kinghorn and Yorke. Merely to infect laboratory animals with a trypanosome morphologically identified with T. rhodesiense does not prove that this trypanosome is T. rhodesiense, or that the district from which the trypanosome came is a sleeping-sickness area. He says that in East Nyasaland T. brucei can be distinguished from the trypanosome of sleeping sickness only and solely by the fact of its non-pathogenicity to man. Taute supports
