23 



Effect of sunlight. Cover glass preparation made from 24-hour 

 old bouillon culture and exposed to direct sunlight gave the following 

 results : — 



] + . f + 



15 minutes r 30 minutes \ 



f + ' f + 

 45 ' \ 1 hour j 



1.15 hours I _ 1.30 hours | _ 



1.45 " i 2 



Living on some cover glasses but dead on others ; + living ; 



— dead. 



Agar plates inoculated with 1 oese of a fresh bouillon culture and 

 exposed to direct sunlight gave the following results : 



Control plates not exposed J ,200-2,000 colonies per plate. 



("centre, 2-5 colonies per plate. 



Plates exposed 15 minutes '\ , ^.^^ .^„ ,, 

 ^ ( edge, 220-400 



(centre, 0-10 



ledge, 130-200 " 



(centre, 0-1 



[edge, 10-60 



[centre, 



'■ ^ ^^"' ledge, 10-60 



1.30 hours 



The plates were exposed in the afternoon between 2 and 4 p.m. 

 in the month of October. Temperature of the plates, 30' C. Lati- 

 tude, 43% 30." 



Resistance of the organism to desiccation. For determining the 

 resistence to dessication cover glass preparations were made from a 24- 

 hour old bouillon culture and exposed to the light in a room for 

 various periods of time. Under these conditions the bacillus was 

 killed after two days exposure. 



Growth in Fermentation Tithes. The foundation medium was 

 composed of 1 per cent, peptone, .25 per cent. Nahrstoff Heyden, and 

 5 per cent, salt, with the reaction carefully neutralised to phenolphta- 



