198 NORBERT SCHUMMELFEDER 





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Fig. 6. At L!U hours alter irradiation with lU.OOU r, showing the honiogenization type 

 of nerve cell necrosis. X 700. Hematoxylin-eosin. 



the irradiated field and was sharply demarcated from the nonirradiated part 

 of the cerebellum. The molecidar layer showed granidar and clumped areas 

 of disintegration. Only some of the nerve and glial cells were preserved. 

 Most of them contained pyknotic nuclei and showed all stages of disinte- 

 gration or lysis. Within the necrotic granular layer enlarged by edema, the 

 preserved nuclei were pyknotic, and between them nuclear debris was 

 frequently found. Hemorrhages and extravasations of plasma proteins were 

 remarkable neither within the necrotic granidar layer nor within the white 

 matter. The nuclei of the glial cells in the white matter of the more super- 

 ficial part of the cerebellar folia (nearest the radiation source) were pyk- 

 notic, and in deeper parts of the cerebellum they were swollen. Some blood 

 vessels in the necrotic area were preserved, but dilated. Frequently, they 

 were surroimded by a hollow space, the ground membrane had often under- 

 gone hyaline thickening (hyalinosis) , and there was swelling of endo- 

 thelial and adventitial cells. 



Within the irradiated field the Purkinje cells had, in part, disappeared. 

 Most of the preserved Purkinje cells showed homogenization. They con- 

 tained pyknotic nuclei and exhibited a strong cytoplasmic eosinophilia. 

 Many were in all stages of disintegration, including cell shadows. 



At 90 hours after irradiation^ necrosis was completely established in all 



