A preliminary note on the separation and infectivity of tissue forms of Trypanosoma brucei

Infective forms of T. brucei present in the liver and spleen of infected mice can pass through filters of pore size 0.8–1 μ diameter. However, the infective forms present in the blood of these same mice can pass through filters of pore size 3 μ or larger. Tissue forms were found in the spleen and liver of mice inoculated with infective tissue filtrates 72 hours after inoculation, while blood forms were present 24 hours after inoculation. However, if blood forms were inoculated into mice, tissue forms were present in spleen and liver in about 24 hours.