Brilliant results have attended the efforts of the Portuguese to combat sleeping sickness in the island of Principe, where the annual mortality from the disease amounted to 83 per thousand of the population, and the local industry (cocoa) was threatened with extinction. In addition to jungle clearing, drainage, blood examinations and segregation of infected, and destruction of possible animal reservoirs of the trypanosome, coolies, dressed in white and carrying on their backs a dark cloth smeared with bird-lime, were sent into the jungle, and every night the flies caught were removed and counted. In three years 470,000 glossinæ were caught. As a consequence of this combination of sanitary measures the fly and the sleeping sickness were exterminated. Of course it was only the complete 'isolation and the limited size of the island that made such a result possible.
Koch, from observations in Uganda, suggested that trypanosomiasis may be communicated by the male during coitus. The phenomena of dourine and recent animal experiments support the idea, although the experiments referred to indicate that the risk is not great.
A. complete scientific prophylaxis can be indicated with certainty only when we have full knowledge (1) of the habits of the tse-tse flies and of the reasons for their restriction to very limited and apparently capriciously distributed areas; (2) as to what vertebrates under natural conditions are normally hosts of T, gambiense. Experiment has shown that the glossina will bite any vertebrate, and that it can infect a large variety of mammals with the trypanosome. If this be the case in the laboratory it is reasonable to suppose that it is the case in nature also. Therefore, in the endemic regions of trypanosomiasis, the vertebrate fauna has to be reckoned with as a source and reservoir of infection.
In Uganda and elsewhere, principally with a view of preserving the hitherto uninfected from trypanosome infection, Government removed the entire population of the Sesse Islands and neighbouring
