X-IRRADIATED CNS OF THE SYRIAN HAMSTER 



267 



Fig. 7. Cerebral cortex, 73 hr after exposure to 45,000 r. Beginning necrosis with 

 dissociation of the components of neuropil and disruption of some of their membranes. 

 Nerve cell (N) shows widening of the endoplasmic reticulum and swelling of mito- 

 chondria. Ex, exudate. X 4.000. 



as the one shown here, contain a nucleus which morpholooically is still essen- 

 tially normal, while the cytoplasm shows changes of questionable significance, 

 including widening of endoplasmic reticulum and mitochondrial swelling. 

 There is good preservation of RNA granules. 



In Fig. 8 one can see a still more severe stage of tissue destruction. Here, 

 a small artery is in a state of relatively good preser\ation. despite extensi\e 

 necrosis of the surrounding tissue. The outer margin of the perivascular space 

 is no longer intact. Perivascular macrophages and leucocytes are seen in 

 contact with the necrotic neuropil. The dark round bodies are probably 

 ingested fragments of erythrocytes. 



Figure 9 illustrates total dissociation of tissue components so that only cell 



