220 



W. SCHOLZ, W. SCHLOTE AND W. HIRSCHBERGER 



trated into the tissue. This region was completely stained blue with trypan 

 blue injected subcutaneously shortly after the irradiation. 



To clarify these observations, the experimental technique was modified 

 in two diflferent ways: (1) we diminished the x-ray dose to 1,000 r, and 

 (2) we shortened the survival time to 1 hour, using x-ray doses large enough 

 to produce complete tissue necroses. With the first of these methods, the 

 size of the necrotic area decreased, so that with 5,000 r only a small tan- 

 gential zone of the cortex including the first and second layer was affected. 

 These lesions developed within about 8 days. The nerve cells and glia cells 

 lost their cytoplasm, and their nuclei were shrunken. A few polymorpho- 

 nuclear leucocytes were scattered throughout the necrotic tissue. This small 

 necrotic zone was surrounded by a broad region of spongy tissue containing 

 numerous tiny hemorrhages. Within 6 days, an application of 10,000 r 

 produced a larger zone of necrosis extending through the whole cortex 

 (Fig. 11). In these cases the first reactive processes had begun, and several 

 fat granular cells and progressive glial cells were found at the borders of 

 the necrotic tissue, especially near the pia. However, within the center of 

 the necrosis nothing seemed viable. Here again, the zone of hemorrhages 

 was considerably more extensive than the necrotic area. The necrotic zone, 







i^ 



Fig. 11. Large, sharply bordered areas of acute radionecrosis invohing the whole 

 cortex and corpus callosum and containing numerous, partly confluent, diapedetic 

 hemorrhages; 10,000 r with 6 days survival. Azan stain. 



