148 
Journal of Agricultural Research 
Vol. XXV, No. 3 
and there was no visible growth in the closed arm. With dextrose the 
line of demarcation was only slightly above the inner part of the U. No 
gas formed in the closed arm in any case. 
ACID PRODUCTION 
In addition to the fermentation tubes used for determining gas produc¬ 
tion, three 100 cc. Erlenmeyer flasks were prepared in triplicate for each 
of the sugar solutions. Fifty cc. of the peptone-sugar solution was added 
under aseptic conditions to each flask. The media were then uniformly 
inoculated and incubated at 25 0 C. The acidity was determined by both 
Fuller’s scale and hydrogen-ion concentration methods after different 
periods of incubation. Twenty cc. of the solution was removed with a 
sterilized pipette from each flask for the determinations. Of these 
cultures acid was produced only in those containing dextrose and saccha¬ 
rose. The other cultures became slightly more alkaline as indicated in 
Table I. 
Table I .—Production of acid from sugars and glycerine 
Carbon compounds used in 
experiment. 
Control. 
Reaction after different periods of incubation. 
10 days. 
30 days. 
Fuller’s 
scale. 
Ph. 
Fuller’s 
scale. 
Ph. 
Fuller’s 
scale. 
Ph. 
Dextrose. 
+ 12 
8.0 
+ 14 
7. 6 
+48 
4. 4 
Saccharose. 
+ 13 
8.2 
+ 22 
6.4 
+45 
4-6 
Mannit. 
+ 12 
8. 0 
+ IO 
8. 2 
+ 16 
8.6 
Maltose. 
+ 12 
8. 2 
4 -ix 
8 6 
Lactose. 
I O 
+ 13 
8.2 
+ 12 
8.4 
1 x * 
+10 
9. 2 
Glycerine. 
+ 13 
8.2 
+ 11 
8.6 
+11 
8.6 
NITRATE BROTH 
In fermentation tubes nitrate broth gave heavy clouding in the open 
end and none in the closed end; no gas was formed. A positive test for 
ammonia was obtained with Nessler’s reagent at the end of 2 and 3 
weeks. Trommsdorf’s reagent gave a negative test for nitrites. There¬ 
fore nitrate was reduced completely to ammonia. 
digestion of casein 
Clear casein agar plates were inoculated with the type organism. 
After 3 days a test with 1 per cent hydrochloric acid indicated that the 
casein was digested around the colonies. After 2 weeks the whole plate 
was clear, indicating rapid digestion. 
vitality on culture media 
Cultures kept in the ice box may be kept alive indefinitely on nutrient 
agar by transferring every month. The organism may be recovered from 
2 to 3 months old cultures on potato or nutrient agar by transferring to 
nutrient broth. At laboratory temperature potato and nutrient agar 
cultures lose their viability after 2 or 3 months. 
