INFLUENCE OF ILLUMINATING GAS ON BACTERIA AND FUNGI 
13 
restored to the air. In pure gas no development occurred during the 
exposure. In one case no development followed a 3-day exposure 
within 18 days after removal, and in another a 6-day exposure was 
followed by no development within 22 days, while in a third a very 
slight development began 5 days after the close of an 8-day exposure. 
Sarcina lutea. — This proved to be one of the more susceptible 
organisms studied. It was, however, grown in 5 percent, 10 percent, 
25 percent, 50 percent, 75 percent, and 85 percent of illuminating gas. 
There was ordinarily no checking of the development in the 5 percent 
concentration, but the growth gradually became less in all higher 
concentrations used. In all tests the air cultures reached their full 
development first, followed in succession by the others; but only rarely 
in 50 percent and above did the maximum in gas equal the maximum 
in air. The organism was carried continuously through 5 transfers 
in 5 percent, 10 percent, and 25 percent gas, 3 transfers in 50 percent, 
and 10 transfers in 75 percent. It was found impossible to secure 
unmistakable development in pure gas although there were a few 
cases of possible very slight development. 
Oidium lactis. — 0. lactis showed about average resistance to the 
effects of the gas. It was grown in all concentrations of illuminating 
gas employed, but its behavior in the stronger concentrations was 
rather erratic. Usually the growth under such conditions was very 
slight; and sometimes it started from only a few isolated points 
along the streak, as if the treatment had partially sterilized the slant; 
but at other times it would approach the maximum reached by a 
culture in /air if left long enough. It was grown continuously for 5 
transfers in 5 percent, 10 percent, and 25 percent gas, 3 transfers in 
50 percent, ii transfers in 75 percent, and 5 transfers in 85 percent 
and ICQ percent. At times the character of the colony development 
in large percentages of gas differed from that in low percentages or 
in air, but here again the reaction was not uniform. In some tests 
the mycelium was more appressed and water-soaked in appearance in 
a high gas atmosphere and in others it was more upright and tufted 
or white velvety in appearance. 
Cryptococcus Ltidwigi. — This organism did not show any particu- 
larly remarkable characteristics in connection with these studies. 
Normally the colony is deep pink in color and is composed of quite a 
considerable mass of material. In gases the toxic effects are evidenced 
by a retarded or incomplete development of the colony and by a 
