44 ROBERT H. BROWNSON 



a \2^c decrease in body weisjht by the 228th day after initial exposure. 

 These animals all demonstrated thinnina or diffuse loss of hair about the 

 head with complete epilation around the eyes. All had \vell-de\eloped 

 bilateral, posterior subcapsular cataracts. One animal developed a tumor of 

 the head, a low grade carcinoma of the skin. 



Group C animals (Table I and Fig. 12) received a total of 3,000 r during 

 3 weeks and were sacrificed 165 days after the initial exposure. The average 

 decline in body weight over this time indicated approximately a 17 ^c loss. 

 These animals all demonstrated a rather severe diffuse loss of hair about 

 the head with complete epilation aroimd both eyes. 



Group D animals (Table I and Fig. 12) accumulated a total dosage of 

 4,000 r during 4 weeks. Three of the animals were sacrificed after 158 days 

 and demonstrated an approximate 20*"^ weight loss. 7\vo of the animals 

 died after 44 days and demonstrated a loss of 319f of body weight. All 

 animals showed diffuse loss of hair over the head with complete epilation 

 around the eyes. 



Group G animals (Table I) accumulated 5,000 r during 5 weeks. Two 

 animals were sacrificed after 116 days and demonstrated approximately a 

 29% loss of body weight. All animals demonstrated severe, diffuse loss of 

 hair over the head region with complete epilation around the eyes. 



The animals indicated thus far. in experimental groups A, B, C, D, and 

 G along with their controls, ha\'e been utilized in behavioral studies during 

 the first 5 weeks following radiation. The weight loss demonstrated by these 

 animals, including controls, during this testing procedure was in part due 

 to forced food deprivation. The calculations for weight loss were based on 

 per cent of difference between controls and experimentals which allows for 

 the standard weight reduction due to a decrease in rations. 



Certain animals died or were sacrificed as they became moribund, espe- 

 cially in the 4,000 and 5,000 r dose range. Apparently this high mortality 

 rate in these groups after total head irradiation is more inxolved than ap- 

 parent. One additional group of animals, group F, recei\ed the same treat- 

 ment as did group G, with the exception that these animals were not utilized 

 in behavior studies and did not imdergo food deprivation. None of the 

 animals in this group expired or appeared moribund before the date of 

 sacrifice 228 days after initial exposure. All animals in this group had 

 well-developed bilateral posterior subcapsular cataracts and the usual epi- 

 lation. 



All groups of animals with the exception of group F underwent a pre- 

 liminary analysis of behavioral characteristics in operant conditioning 

 equipment. Results from a preliminary analysis of animal behavior indicated 

 that, from the first day of exposine to x-irradiation, all groups of animals 

 through and including the 4,000 r group demonstrated some decrease in 



