500 Bulletin 167 



tubes, sterilized by flowing steam on eacb of three consecutive 

 days, and inoculated in the usual way. At the end of 8 days gas 

 production in the closed arm was as follows: Maltose 22%, 

 dextrose 15%, sucrose 12/0, lactose $'-/> , and mannit 14%. The 

 composition of the gas was similar to that previously described. 

 Gas production in maple sap and in starch jelly containing modi- 

 fied Uschinsky solution has been mentioned under cultural char- 

 acters. 



Ammonia production was determined in 100 cc. portions of 

 nutrient broth in 500 cc. flasks inoculated with 1 cc. portions of 

 young cultures and incubated at room temperatures, 20 to 23 ° C. 

 Determinations were made at the end of 5, 10 and 12 days. For 

 this purpose an excess of heavy magnesium oxid and 100 cc. of 

 distilled water were added. The flask was connected with a 

 Liebig condenser and distilled, the distillate being received in a 

 flask containing a measured quantity of N/20 hydrochloric acid. 

 The excess of acid was titrated against cochineal as an indicator 

 and the ammonia production calculated. An equal volume of the 

 same broth which had been kept under identical conditions was 

 analyzed for ammonia at the same time. The results are recorded 

 in the following table: 



TABLE 46. AMMONIA PRODUCED IN NUTRIENT BROTH 





cc. N/20HC1 cc. N/20NH 



neutralized produced 



Age Inoculated Control per 100 cc. broth 



5 days, 11.80 — 2.00 = 9.80 



10 days, 36.20 — 4.20 = 32.00 



12 days, 33.15 — 4.75 = 28.40 



12 days, 28.25 — 4.25 = 24.00 



Nitrate reduction. — Nitrate broth was prepared according to 

 the following formula: One liter distilled water, 3 grams 

 Liebig' s extract of beef, 10 grams chemically pure potassium 

 nitrate. The reaction was adjusted to zero with sodium hy- 

 droxid. The organism made vigorous growth upon this medium 

 as exhibited by the prompt clouding and production of sediment. 

 There was a marked tendency towards clearing in the upper 



