X-RAY INDUCED CNS CHANGES 49 



severe at 5,000 r. Some petechial hemorrhages were seen. The animals that 

 underwent 4.000 r exposure showed a more severe reaction. Apparently 

 there was a consistent increase in connective tissue, presumably peri\ascular, 

 from mild to se\ere within the hypothalamus from 1.820 to 5.000 r (Figs. 9, 

 10. and 11 j. 



Discussion 



There were no remarkable or otherwise consistently observable neurologic 

 deficits in animal activity during the 228 days following irradation. If any 

 such alteration could be detected by observation alone, one might describe 

 malaise. 



The animals" physical appearances were altered by cataracts and varying 

 degrees of hair loss about the head. There was complete epilation of hair 

 immediately surrounding the eyes in a circumscribing area approximately 

 3 mm wide. In most instances the hair o\er the remaining portion of the 

 rat's body lost its usual healthy sheen and became ruffled. Some of the 

 animals had inflamed margins of the eyes which might be described as 

 blepharitis. 



Analysis of weights indicated that beginning with group B at 2,000 r le\ el 

 there was a decline in animal body weight. This was in the approximate 

 magnitude of I2''r of control animal weight at the time of sacrifice 

 228 days after initial exposure. Additional cumulative exposure to x-ray 

 revealed a similar weight loss in the animals at sacrifice. The per cent of 

 difference between the remaining groups of control and experimental animal 

 weights became increasingly greater with increasing dosage. The greatest 

 factor of difTerence was at the 5.000 r level where a loss of 29'^r was noted. 

 However, the percentage weight differences indicated were taken only from 

 weight differences at the time of sacrifice for the group as an a\"erage. In 



Fig. 2. Cerebellar granule cell pyknosis and hyperchromatic staining reaction 228 

 days following 5,000 r. NissI: X 320. 



Fig. 3. Cerebellar granule cells demonstrating normal staining reaction. Nissl; 

 X 320. 



Fig. 4. Cerebral corte.x focal area of pyknotic and hyperchromatic stained neurons 

 228 days following 5,000 r. Nissl; X 130. 



Fig. 5. Cerebral cortex cellular gliosis and thickened pial-glial membrane with 

 some cellular and fibrous infiltration of subarachnoid space 228 days following 5.000 r. 

 Hematoxylin and eosin ; X 130. 



Fig. 6. Cerebral cortical infarct. Small with slight encapsulation of necrotic area 

 228 days following 1.820 r. Verhoeff; X 320. 



Fig. 7. Ependymal cells and area of subependymal cell pyknosis and hyperchromatic 

 staining reaction 228 days following 5,000 r. Nissl; X 320. 



