432 



EFFECTS OF RADIUM RADIATIONS ON WHITE MICE 



the mode of application was the same as in Experiment 4. The con- 

 trols of either sex were all fertile. The first litter of young from both 

 radiated and non-radiated female mice was obtained between the 

 60th and 78th day after birth. The radiated males reached sexual 

 maturity at about the same time as the controls. The young born 

 from the radiated mice grew normally and in turn produced normal 



TABLE III. 

 Efed of Radium Radiations upon Longevity of White Mice, 



* Final observation made November 20, 1921. 



young, judging from their general appearance, weight, and repro- 

 ductive power. 



Davey^ has reported some experiments with tribolium confusum 

 in which by small doses of x-rays he was able to prolong the average 

 life of the beetles. He used a very large number of specimens, and 

 the statistical results are quite reliable. From our experiments, how- 

 ever, no definite conclusions can be reached as to the effect of radia- 



