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Fig. 22. Sections of tumor. Mouse bearing twelve day old sarcoma i8o received loo 

 units of B. typhosus "agar washings" filtrate intravenously. A (X 220) , histologic ap- 

 pearance of tumor forty-eight hours after injection. Note wide zone of necrosis de- 

 marcating residual tumor. B (X 50) , histologic appearance eight days after injec- 

 tion. Note small residual mass of timior undergoing necrosis and regression. 

 (Shwartzman, 1936b.) 



