290 



A. C. UPTON, M. A. KASTENBAUM, AND J. W. CONKLIN 



the mortaKty of specific diseases. For example, for thymic lymphoma (Fig. 

 9), mortality rate reached a peak dm-ing the first year of life in the irradiated 

 mice, contrasting with that in non-irradiated controls. For myeloid leukaemia 

 (Fig. 10), the trend was similar but less pronounced and a bimodal distribution 







10 



15 20 



Age (months) 

 Fig. 9. Age-specific mortality rate of RF male mice dying with thymic lymphoma, as 



influenced by X-irradiation early in Ufe (arrow denotes age at exposure) 



O Non-irradiated control (51/882 mice); A 100-200 rads (104/897 mice); 

 (378/1905 mice). 



300 rads 



005 



15 20 



Age (months) 



35 



Fig. 10. Age-specific mortality rate of RF male mice djong with myeloid leukaemia, as 

 influenced by X-irradiation early in life (arrow denotes age at exposure). 



O Non-irradiated control (34/882 mice); A 100-200 rads (184/897 mice); • 300 rads 

 (533/1905 mice). 



