Fig. 21. Sections of tumor; X 220. A mouse bearing twelve day old sarcoma 180 re- 

 ceived 100 units ol' B. typhosus "agar washings" filtrate intravenously. A, histologic 

 appearance of tumor four hoius after injection. Note severe hemorrhage. Many viable 

 cells are present. B. histologic appearance twenty-four hours after injection. Note 

 extensive necrosis and hemorrhage. (Shwart/man. iggO/^) 



