X-RAY INDUCED CNS CHANGES 43 



sacrificed after receivins; a total cumulative dosaoe of x-irradiation as 

 follows: Group A, 1,820 r; Group B, 2,000 r: Group C:. 3,000 r; Group D, 

 4,000 r; Group G. 5,000 r; and Group F, 5.000 r. 



All animals, control and experimental, were anesthetized with sodium 

 nembutal and surs;ically prepared for perfusion \ia the left \entricle ot the 

 heart. Perfusion pressure was maintained at approximately 90 mm of Ha;. 

 Initially, the major portion of the circulatint; blood volume was removed 

 by washina: the cardiovascular system with physiologic saline. A small in- 

 cision in the right atrium provided a means ot exit for the perfused fluids 

 and blood. Subsequently, with the heart still pidsatins;, the fixatives were 

 perfused. Three animals received saline-acacia formalin, while the fourth 

 animal received acetic acid-alcohol formalin. The partially fixed brain was 

 then rapidly removed and cut by coronal sections into three parts: a frontal, 

 midcoronal, and occipital plus brain stem and cerebellum. Each of the sec- 

 tioned brains was then immersed in its respective fixative, formalin and 

 acetic acid-alcohol formalin alona, with the control for each fi.xative. 



Following the usual histologic techniques, specimens fixed in acetic acid- 

 alcohol lormalin were processed for histochemical analysis utilizing the 

 periodic acid-Schiff" reaction (PAS) for olycogen. Specimens that were 

 fixed in formalin-acacia were stained with toluidine blue for Nissl material 

 and glia, azocarmine and VerhoefTs procedure for connective tissue and 

 interstitial cell reaction, WeiTs method for general identity of structures 

 and axon pathways, Swank-Davenport modification of Marchi method for 

 degeneration of myelin, and Bodian's method for nerve fibers and nerve 

 endings. 



Results 



Following each exposure to x-irradiation the animals showed behavioral 

 changes which were unremarkable and somewhat variable. The animals in 

 general exhibited confusion, sluggishness, or malaise, as expressed by with- 

 drawal to the back of the cage. Generally, during the 24 to 72 hours follow- 

 ing exposure, most animals appeared to recover from a postirradiation 

 malaise. 



Group A animals (Table I and Fig. 12) survived 228 days after receiving 

 a single exposure of 1,820 r and exhibited little or nothing in the way of 

 physical changes. There occurred some slight weight loss during the first 

 week which appeared to return to normal by the third week. One animal 

 developed a head tumor, a benign involvement of the salivaiy glands, well 

 encapsulated with a caseous center (sclerosing angioma). 



Group B animals (Table I and Fig. 12) received two successive exposures 

 of x-ray totaling 2.000 r. The animals in this group averaged approximatelv 



