DEATH RATE AFTER IONIZING RADIATION 



287 



whether mice with, or without, neoplastic disease were excluded from con- 

 sideration (Figs. 5-8). Inflections in the curves suggested heterogeneity in 

 the various animal popidations, which became more apparent on inspection of 



100 



10 15 20 25 



Age (months) 



Fig. 3. Age-specific mortality rate of RF male mice, as influenced by X-irradiation early 

 in life (arrow denoted age at exposure). 



O Non-irradiated control (882 mice); A 100-200 rads (897 mice); • SOOrads (1905 mice). 



o 



D 



150 300 450 600 

 Age (days) 



750 



900 



1050 



Fig. 4. Age-specific mortality rate of RF female mice as influenced by X-rays, TEM, or 

 HN2 administered early in life (arrow denotes age at treatment). See Methods for doses. 

 O Untreated control (130 mice); • HN2 (160 mice); A TEM (157 mice); D X-ray (259 mice). 



