of atoxyl, there is later likely to be a recrudescence; and it was for this reason that two chemists at Liverpool, Professor Benjamin Moore and Dr. Nierenstein, conducted still further research for a better remedy. These men found that although atoxyl killed most of the organisms, a resistant form was able to withstand the action of the drug. A second remedy was then given during this resistant stage, and success seemed assured. The disease may continue for many years, however, so it is too early to know how effective the double remedy is in man.
It is interesting to observe that as in malaria the complete lifecycle of the parasite was first followed in bird malaria; so in sleeping
sickness what is apparently the complete cycle has been worked out in trypanosome infection of the frog. It was observed by Dutton in the Congo that the frog trypanosome undergoes another cycle of development outside the frog; and the recent experiments of Kleine in German East Africa seem to point to another cycle of development of the trypanosome of man in the tsetse fly. Thus the study of infections in lower animals may be of the greatest assistance in solving the problems of disease in man.
The other of these two diseases of Central Africa is tick fever. This infection was first described by Dr. Livingstone, the famous explorer, who found the disease in Portuguese South Africa, and attributed it to the bite of a tick. The discovery that spirochætes could be found in the blood of every patient ill with tick fever was first published by P. H. Ross and Milne, though there has been some doubt whether their work antedated that of Dutton. However, Dutton was
