62 YAMAZAKI, BENNETT AND CLEMENTE 



TABLE I 



Weight of Head-Irradiatkd Rats at 3 Months of Age 



No. of animals Range (gm) Average weight (gm) 

 Male 



of eye patholo<iy niiiiht have been found in animals radiated under 4 days 

 of as^e had they been able to survive for longer periods. 



Animals radiated during the first 5 days of life tended to weigh less than 

 controls (Table I). Mortality was also greatest in the animals irradiated 

 during this immediate neonatal period, and, with one exception, all deaths 

 under 3 months of age occurred in this group. The average survival periods 

 of the animals that died under 3 months of age were 0.9 months for the 

 1.000 r animals, and 2.3 and 2.4 months for the 300 and 500 r animals, 



TABLE II 

 Mortality in Head-Irradiated Rats 



Radiation dose Age at the time of irradiation 



(r) Under 4 days 5-6 days 7-15 days 



125 0/3 — — 



300 3/9 — 0/2 



500 5/13^' 5/17 0/3 



1,000 9/11" 1/2 2/14 



One anesthetic death. 

 ' Two anesthetic deaths. 



