52 



NEUTRON EFFECTS ON ANIMALS 



Fig. 3. Comparison of the development, during the first four hours after planting, 

 of cultures obtained from irradiated and unirradiated samples of E. coli. Counts 

 made at 15 min. intervals. Subculture maintained at 28°C. 



Fig. \. The development of cultures from samples irradiated during active multi- 

 plication, compared with similar unirradiated sample. 



planted only a few hours before exposure. The organisms were thus in the 

 logarithmic phase of development during bombardment. They remained 

 so when transferred to fresh medium, so that no lag phase was found. 



