observes on its distribution that "it seems probable that as our knowledge of Africa extends, this disease will be found endemic here and there throughout the basins of the Senegal, the Niger, the Congo, and their affluents. We have no information of its existence in the districts drained by the Nile and the Zambesi, nor anywhere on the eastern side of the continent." As far as my own knowledge goes the centres of this disease are the Senegal and the Congo. I never saw a case in the Oil Rivers, nor could I hear of any, though I made every inquiry; the cases I heard of from Lagos and the Oil Rivers were among people who had been down as labourers, &c., to the Congo. What is the reason of this I do not know, but certainly the people of the lower Congo are much given to all kinds of diseases, far more so than those inhabiting the dense forest regions of Congo Français, or the much-abused mangrove swamps of the Niger Delta.
Dr. Manson says, "The sleeping sickness has been attributed to such things as sunstroke, beriberi, malaria, poison, peculiar foods, such as raw bitter manioc, and diseased grain; it is evident, however, that none of these things explains all the facts." In regard to this I may say I have often heard it ascribed to the manioc when in Kakongo, the idea being that when manioc was soaked in water surcharged with the poisonous extract, it had a bad effect. Certainly in Kakongo this was frequently the case in many districts where water was comparatively scarce. The pools used for soaking the root in stank, and the prepared root stank, in the peculiar way it can, something like sour paste, with a dash of acetic acid, and thereby the villages stank and the market-places ditto, in a way that could be of no use to any one except a person anxious to find
