X-Ray Sensitivity 



101 



for both sulphydryl compounds is about 0-02 M. Other 

 experiments have shown that addition of increasing concen- 

 trations of cysteine to the optimum concentration of BAL 

 failed to increase the survival; whereas below the optimum 

 concentration of either compound, the compounds are com- 



BAL(0.04M) 



10— 



s 



^- 

 < 



u 



z 

 > 

 > 



K 



iO-1, 



,-■£, 



_-»■• 



— r- 



30 



T- 

 60 



OOSE(kr) 



— I— 

 90 



Fig. 3. Survival of E. coli in standard buffer and . 04 M BAL. 

 Burnett, Stapleton, Morse and Hollaender (1951), in press. 



pletely additive in their protective capacity. The greater 

 survival at optimum concentration for BAL might be 

 explained by the fact that the parent compound of BAL, 

 propanol, is also somewhat protective or that BAL contains 

 two sulphydryl groups (Burnett, Stapleton, Morse, and 

 Hollaender, 1951). 



