Profs. Percy Frankland and Marshall Ward. 



2-0 ao 40 3O EO 40 4-0 ao 40 5-0 20 40 60 20 40 7-0 20 40 



On August 3 spores were sown in broth + 1 per cent, gelatine, at 

 10 A.M., and exposed as follows. Each of two cultures had a black- 

 ened matchbox cover pierced with a hole, so as to diminish radiation 



