Published online by Cambridge University Press: 15 May 2009
1. The effect of virulent bovine tubercle bacilli on rabbit tissue in vitro was studied.
2. When normal spleen cultures were infected in vitro the cells actively phago- cyted the bacilli. At first the phagocytes tolerated the organisms, and in the course of their wanderings spread the infection throughout the tissue. Some infected cells even underwent mitotic division.
3. Eventually the infected cells broke down, and the freed bacilli continued to grow in the tissue. Fourteen days after infection, outgrowth had usually ceased and the explants were almost completely replaced by bacilli.
4. Actively growing spleen cultures were unable to suppress even a slight infection with virulent bovine bacilli.
5. No tubercles were formed in the cultures.
6. There were no indications ofan exotoxic action of the bacilli on the cells in tissue culture, an densely infiltrated explants were often surrounded by a large zone ofoutgrowth.