A^m,77- 



2mm 



I'lG. 7C. Rat brain (H. & E. X 6.8) 24 days after the same duse and aperture as 

 used in the monkeys in Figs. 7A and 7B. Without magnification or with the help of 

 low magnification, it can be seen that in the cortex there is a decrease in the staining 

 quality of the ground substance with some capillary dilatation. No changes were 

 recognized in the white matter (corpus callosum). 



Fig. 7D. Higher power magnification (X 26) of the area of the cortex showing 

 changes. Microscopic examination of the brains of rats from the same group autopsied 

 at 20 days or less after irradiation showed no recognizable morphologic changes. 



378 



