22 



The tests for nitrites on the 9tli day were negative, on the 

 fifteenth day there was a faint pink tinge with the napthylamine and 

 sulphanilic acid test. Control tubes kept under the same conditions 

 gave no indication of nitrites. 



Indol production. See Dunham's solution. 



DevelopTnent of odors. The strongest and most offensive odor 

 developed on onions, both raw and cooked. There were objectionable 

 odors from cultures on cabbage, cauliflower, horss radish, rape and 

 turnips. 



The odor on white carrot was pungent. Milk cultures when 

 heated give an odor of fresh curd. 



Production of hydrogen sulphide. Strips of filter paper moistened 

 with lead acetate were suspended over bouillon and potato cultures. 

 In both cases the paper turned black indicating the production of 

 hydrogen sulphide. 



Production of acid. Acid was produced in all sugar media, in 

 milk, in Dunham's solution, and in bouillon. 



Production of alkali. Ammonia was produced in potato cultures 

 in considerable amount, it could be detected by the smell, as well as 

 more exactly by Nessler's reagent. Cultures on several other vege- 

 tables (turnips, carrots, beets) also gave the Nessler reaction. 



Relation of growth to acid and alkali. Various quantities of 

 normal soduim hydrate and normal hyrochloric acid were added to 

 neutral broth. The following results were from 4S-hour old cultures 

 kept at 28" C. 



Neutral broth. Turbid and considerable sediment. 

 Alkaline bro^h + lOc.c. of normal NaOH per litre: Same as neutral tubes 



(( CC t( (( ( 



9A u « ti tt 



30 " " Turbid and slight sediment. 



40 " " Very slight turbidity. 



50 " " Quite clear, no growth. 



Acid broth + 10 c.c. of normal HCl per litre : Turbidity greater than 



in control. 



20 " " Same as neutral tubes. 



80 " " Slight turbidity. 



50 " " Very slight growth. 



