522 



DOROTHEA STARBUCK MILLER 

 TABLE IV 



Incidence of Audiogenic Seizures in C57-backcross Generation" Mice 

 UNDER Different Environmental Radiation Levels 



1956-57 (back- 

 ground r) 

 Room G 



120 



First trial 

 seizures (%) 



8.3 



7.5 



Four trial 

 seizures (%) 



21.7 



18.3 



1957 (5-10 X back- 243 

 ground r) 

 Room R 



21.4 



15.6 



25.5 



19.8 



1957 (shielded by 

 lead) 

 Room R 



105 



11.4 



9.4 



13.3 



10.4 



F^ generation derived from DRA/1 by C57BL6. 



TABLE V 



First Trial Incidence of Audiogenic Seizures in Mice of Backcross 

 Generation (Fi X C57BL6) under Various Environmental Conditions" 



" Key: Regular type, backcross in Room G; Italic type, backcross in Room R; Boldface, backcross 

 irradiated at Argonne. 



