The application of tissue culture methods has led to but few conclusions of greater clinical interest than the recent demonstration of the altered growth vigor of fixed tissue cells as a result of somatic sensitization to certain bacterial products. The first studies of the in vitro effects of specific bacterial antigens on tissue cultures were made about ten years ago by Rich and Lewis1 of Johns Hopkins University. These investigators found that the addition of human type tuberculins to explants from the spleen of tuberculous guinea-pigs inhibited the growth and caused degeneration in these explants. The same tuberculins had no demonstrable toxic effects on explants from nontuberculous guinea-pigs.
This observation was adequately confirmed about four years later by Aronson2 of the Phipps Institute at the University of Pennsylvania, who studied the allergic toxicity of tuberculins of avian, bovine and human type on explants from bone marrow, spleen and testes