INFLUENCE OF ILLUMINATING GAS ON BACTERIA AND FUNGI 23 
Bacillus ruhidus. — The concentrations in which B. ruhidus was 
tested were 0.4 percent, 4-5 percent, 85 percent, and 100 percent, 
uncorrected values. There were no cultures with analyzed gas for 
verification. In the first three percentages the cultures were on 
autoclaved potato, in the last on agar. It grew in all, and when 
growing on the potato produced the characteristic orange-yellow 
pigment freely. 
Sarcina lutea. — This organism was tested in 4 percent, 20 percent, 
40 percent, 60 percent, 85 percent, and 100 percent ethylene, un- 
corrected values; and the results were checked with the percentages 
mentioned at the beginning of this section. The lowest concentration 
at which inhibition occurred was 40 percent, but good growth occurred 
in all. The color of the culture was never much affected. 
Oidium lactis. — This organism grew well in all the gas concentra- 
tions used, the cultures being scarcely distinguishable up to 60 percent 
from those in air. At greater concentrations slight inhibitive effects 
were noted. 
Cryptococcus Ludwigi. — This yeast grew well in all of the tests 
although the development was checked and the color paler in the 
higher concentrations. The lowest percentage at which retardation 
was unmistakable was 40 percent. At 80 percent the growth was 
quite slow at first and the color nearly lacking. In a few days, how- 
ever, the development became greater and the color darker, although 
not equaling that in the air until the return of the culture to the air. 
Penicillium stoloniferum. — This species was tested in 4 percent, 
85 percent, and 100 percent, uncorrected values, of ethylene, and 
the results were verified with analyzed gas as indicated above. The 
organism grew well in all concentrations but was slightly checked at 
40 percent and increasingly so as the concentration increased. 
Bacterium stewarti. — This species was tested in 50 percent and 85 
percent, uncorrected values, of ethylene and the results verified with 
analyzed gas as reported above. It grew well in all concentrations 
used. In the early stages of the exposures there was inhibition at as 
low a percentage as 60 percent or perhaps at 40 percent but, by the 
third or fourth day the effect had disappeared in all. 
The following species were tested, two trials each, in only 50 
percent and 85 percent, uncorrected values, of ethylene. There was 
no confirmatory test with the analyzed gas. 
Bacillus carotovorus. — The development of B. carotovonis while 
