262 



H. HAGER, W. HIRSCHBERGER AND A. BREIT 



treated in the usual fashion, and embedded in methacrylate. Uhrathin 

 sections were examined in a Siemens t)M 100 electron microscope/ 



Results and Discussion 



This preliminary report is concerned only with dosages sufficiently high 

 to produce necrosis. 



Within a few hours after exposure to the radiation the first significant 

 change that could be seen with the electron microscope consisted of swelling 



'"MA 





AP 



'N' 









Fig. 1. Cerebral cortex, 15 hr after exposure to 15,000 r. Swelling of astrocytic 

 processes (AP) in the neuropil and around a capillary (C). N, nerve cells. X 4,250. 



^ The authors gratefully acknowledge the techincal assistance of Miss Luh and Mr. 

 Fellner and the cooperation of Professor Dr. Rollwagen in allowing the use of the 

 electron microscope facilities of the University of Munich. 



