Experimental studies on the infection of Trypanosomes. : III The treatment of Trypanosomes infection and the avqired resistance of the recovered mice.

1) The mice infected with the surra trypanosomes can he cured by the subcutaneous injection of antimony metal colloid (A.M.C.) (Table 1) . The minimum' effective dosis is 0.25cc of ten per cent solution of 1%A.M.C. (Sb 0.00025gram) for mice infected with Tryoanosoma evansi and is 0.2cc of ten per cent solution of 1%A.M.C. ( SbO.0002gram) for mice infected with Trypanosoma gambiense. 2) The minimum effective dosis for rats infected with Trypanosorna evansi is, Ice of ten cent solution of 1%A.M.C. (Sb 0.001gram) (Table 2.) 3) Antimony metal colloid has no prophylactic effect on the surra trypanosome infe-ction. 4) The mice infected with Trypanosoma evansi or Trypanosoma gambiense and treated with A.M.C. were refractory to re infection with the homologous strain, and unable to be infected in four days after the treatment. But the refractoriness of resistance to re-infection decreased day by day and disappeared in twenty eight days after the treatment.