30 
Coi^oRADo Experiment Station 
2.5 and 3 hours, respectively, twO' cover-glasses were removed and 
dropped into tubes of sterile broth which were then inoculated at 
28° C. Growth resulted from all exposures up to and including 
2 hours, but none took place with the 2.5 and 3-ho'ur slips. The 
experiments were made at Fort Collins, Colo., January 21, 1916, 
beginning at 10:55, ending at 1.55, p. m. 
Thinly sown agar plates, with one-half of the bottom covered 
with black paper were exposed to bright sunshine, bottom up, on 
a bed of crushed ice for 15 minutes. Exposure made February 
24, 1916, 2 :o5 to 2 :20, p. m. After exposure, the plates were held 
at 20° C. for four days and the colonies that developed counted. 
An average count of five plates showed that 33.2% of the organisms 
were killed by an exposure of fifteen minutes under the conditions 
of the experiment. The detailed results are given in Table V. 
TABLE V 
Effect of Sunlight 
No. 'colonies on 
exposed half of 
petri-dish 
No. colonies on 
covered half of 
petri-dish 
Gain of covered 
over exposed 
Percent killed 
by sunlight 
21 
30 
9 
30 
22 
38 
16 
42 
28 
46 
• 18 
39 
24 
32 
8 
25 
25 
36 
11 
30 
15. relation to oxygen. —The organism is an obligative 
aerobe. Duplicate inoculations upon agar slants and thickly sown 
agar plates were placed in Novy jars, and a stream of hydrogen 
was allowed to flow thru themi for two hours, after which they 
were sealed. After fifteen days no growth had taken place on 
either slants or plates. When returned to the air, abundant growth 
followed on both, after 48 hours, showing that the organisms had 
not been killed, but merely prevented from developing because of 
lack of air. 
Parallel stroke inoculations on agar plates were covered at 
intervals with flamed cover-glasses so as to exclude all air. No 
growth whatever occurred beneath the glasses, while abundant 
growth took place where the air was not excluded. 
Further evidence of the aerobic nature of the organism is to be 
had in its failure to develop in the closed arm of the fermentation 
tubes. 
16. ferments. —A proteolytic enzyme, probably pepsin, and 
lab ferment are produced. Neither diastase nor invertase is 
formed. 
17. CRYSTALS. —No Crystals have been observed. 
