Fig. 5. A radiation ulcer in a rat with a papilloma at its edge 978 days after exposure to 

 11,000 rads given in 20 seconds at 1-0 Me V. Haematoxylin-Eosin. X 25. 





Fig. 6. A carcinoma at the edge of a radiation ulcer (on right) in a rat 494 days after 2 

 doses of 2,300 rads each given at an interval of two months, at 1-0 MeV. Haematoxyhn-Eosin. 



x2o. 



