NEUTRON EFFECTS ON ANI]VL\LS 



35 



irradiated rats so that only these data have been graphically summarized 

 in Fig. 3. 



When all of the non-irradiated rats, both female and male, were sacrificed 

 after 247 and 248 days on termination of the experiments, no significant 

 gross or microscopic pathologic changes were observed in any organs. 



Gross Pathology 



Females — 251 doses of 1.8 n: The fur of these animals was in poor con- 

 dition. Atrophy of the lymphoid tissue was general together with enlarged 



Fig. 3. Changes in body weight from the day of the initial neutron dose for rats 

 receiving repeated doses of 1 .<S n. Deaths during the course of the experiment are 

 indicated by arrows. O Control males. # Control females. □ Irradiated males 

 receiving 172 X l.S n. fl Irradiated females receiving 172 X 1 .S n. A Irradiated 

 females receiving 251 X 1.8 n. 



and hemorrhagic ovaries. There were some instances of consolidation of 

 one or both lungs to varying degrees, possibly associated with tumor me- 

 tastases. Congestion and enlargement of the uterus was also frequently 

 noted. Eight of the tweh'e animals showed definite tumors on gross 

 examination as summarized in Table II. 



Females — 172 doses of 1.8 n: The fur of these animals was in poor 

 condition. With the exception of a hemorrhagic condition of the ovaries 

 all organs were grossl}^ normal. The data for the two tumors found in one 

 of these six females have been summarized in Table 1 1 . 



Males — 172 doses of 1.8 n: A poor condition of the fur and some slight 



