Dec. io, 1913 
Disease of Sugar-Beet and Nasturtium Leaves 
201 
TEST FOR AMMONIA 
The organism produces ammonia. Beef-bouillon cultures (2 to 8 
weeks old) were tested with Nessler’s solution. Strips of filter paper 
were moistened with the solution and suspended in the tubes to be 
tested. The cultures were then heated in a water bath. A brownish 
red color appeared on the filter paper and in the drops of distillate which 
collected on the sides of the tube. This coloration indicated the pres¬ 
ence of ammonia in the cultures. A second test for ammonia was 
made by placing 25 c. c. of the Nessler’s solution in large-sized tubes. 
Ordinary test tubes of beef bouillon inoculated with the bacterium were 
put into these larger tubes. The inner tubes were left open and the 
outer tubes closed with cotton plugs. After five days a brownish pre¬ 
cipitate had formed in the Nessler's solution, forming a ring on the glass 
tubes at the surface of the liquid. Check tubes used in both tests did 
not show this precipitation. 
TOLERATION OF ACIDS 
Toleration of acids by the bacterium was tested in different percentages 
of tartaric, oxalic, and hydrochloric acid made up in beef bouillon. 
The organism was transferred from bouillon to acid cultures ranging 
from 0.1 per cent to 0.3 per cent solutions. Clouding occurred in 1 day 
in the tartaric acid in a 0.2 per cent solution, but there was no clouding 
in 10 days in a 0.3 per cent solution. In a 0.1 per cent solution oxalic 
add there was slight clouding in 1 day, moderate clouding in 2 days, 
and strong clouding in 3 days, but no clouding in a 0.2 per cent solu¬ 
tion. In the 0.1 per cent solution of hydrochloric acid, growth was 
slow in appearing; the solution became turbid in 1 to 2 weeks, and a 
greenish color was produced in the medium. No growth occurred in 
0.125 per cent solution of hydrochloric acid during 10 days. A final 
test for acid toleration was made in beef bouillon containing hydro¬ 
chloric and tartaric acids (titrating on Fuller's scale from +19 to +35). 
Results of this test showed heavy clouding in 5 days in + 30 beef solu¬ 
tion of both hydrochloric and tartaric acids, while no trace of clouding 
appeared in the + 35 acid bouillons during 4 weeks. 
Toleration of Sodium Hydroxid. —The toleration of sodium hydroxid 
by the bacterium is moderate. Transfers from a 7-day beef-bouillon 
culture clouded —15 beef bouillon in 1 to 2 days, —18 in 10 days, and 
occasionally a slight growth occurred in ---20 after 2 weeks, but there 
was no clouding in — 25 beef bouillon during a period of 4 weeks. 
Optimum Reaction for Growth in Bouillon. —The optimum reac¬ 
tion for growth in beef bouillon is between +15 and +30; the organism 
grows nearly as well at +25 as at +15, and the medium becomes fluores¬ 
cent as in +15. 
