28 
Colorado Experiment Station 
and ill 12 days in +25. Beyond these points no growth took place, 
from which we may conclude that the limits of growth are from 
—9 on the alkaline side to +25 on the acid. 
After 72 hours there was a marked difference in the degree 
of turbidity in the different tubes. From +5 to -j-ii the growth 
was best; from +13 to +19 there was a gradual decrease, and 
beyond +19 there was an abrupt falling off. Going in the other 
direction, there was a heavy growth in +3, but not as good as in 
+ 5; in +i the turbidity was not as decided as in +3, and beyond 
this there was an abrupt drop. 
From this, it appears that conditons for growth became very 
restricted beyond +19 on the one side and beyond +i on the 
other, and altho growth was not entirely inhibited until +27 was 
reached in the one direction and —11 in the other, the optimum 
reaction seems to lie between +5 and +11, probably about +8. 
10. vitality on culture media.^ —Long. By transplant¬ 
ing the culture once every two weeks on nutrient agar, no diffi¬ 
culty has been experienced in keeping it alive and active for ten 
months. 
11. TEMPERATURE RELATIONS. —^Tlie thermal death point lies 
between 49° C. and 50° C. Ten c.c. portions of nutrient broth in 
thin-walled test tubes of uniform diameter (16 mm.) were in¬ 
oculated with one loop of a 24-hour broth culture, and after allow¬ 
ing three to five minutes for thoro diffusion, four tubes for each 
temperature considered were plunged into water of the desired 
temperature up to the plugs. They were left there for exactly ten 
minutes and then immediately cooled in cold water. The water 
in the bath where the determinations were made was kept in con¬ 
stant motion, thus insuring a uniformi temperature, by a horizontal 
paddle operated by a water motor. The effect upon growth was 
determined for each degree of temperature from 45° C. to 55° C. 
Good growth took place in all tubes heated up to and including 
49° C., but none occurred beyond that. 
Optimum temperature.—The best growth was obtained be¬ 
tween 27° and 28° C. No growth takes place at 37^2° G.; good 
growth occurs at 20°, but it is not as abundant as at 28°. 
At 7° C., sufficient growth results in 48 hours to define the 
line of inoculation on an agar streak, while in two weeks the 
growth is about the same as a 24-hour culture at 20° C., i. e. 
moderate. 
12. EEEECT oE DRYING. —The organism is rather resistant to 
drying. Flamed cover-glasses were spread thinly with a suspen¬ 
sion of a 24-hour agar culture in distilled water and allowed to 
dry in the air. They were afterwards placed in sterile, covered 
petri-dishes, and every 24 hours for a period of 22 days, two of 
