PROLONGATION OF LIFE DUE TO X-RAYS 



449 



A. PROLONGATION OF LIFE DUE TO SMALL DAILY DOSES OF 



X-RAYS 



Six groups of approximately 950 individuals each were taken. 



These were known as groups IV, IW, IX, lY, IZ, JA. 



Group IV was the control. 



MAM 



Group IW was given 6| at 50 KV. - 25 MA. daily. 



25" 



MAM 

 Group IX was given 12^ =^^^^ at 50 KV. - 25 MA. daily. 



MAM 

 Group lY was given 25 ^^^^^ at 50 KV. - 25 MA. daily. 



Group IZ was given 50 

 Group J A was given 100 



252 

 MAM 



252 

 MAM 



252 



at 50 KV. - 25 MA. daily. 

 at 50 KV. - 25 MA. daily. 



After 159 days the beetles were practically all dead. The 

 data on the death rates were then collected and plotted as shown 

 in figure 1 . These graphs furnish ample proof that it is possible 

 to reduce the death rate of Tribolium confusum by small daily 

 doses of x-rays. 



Table 1 gives readings from these graphs to the nearest whole 

 number. 



TABLE 1 



