148 BACTERIOLOGY. 
bacillus subtilis require a temperature of 140° C. (dry 
heat) maintained for three hours to insure their de- 
struction. Moist heat at a temperature of 100° C., 
either boiling water or free-flowing steam, destroys 
the spores of known pathogenic bacteria within ten 
minutes; certain non-pathogenic species, however, re- 
sist this temperature for hours. Thus, Globig obtained 
a bacillus from the soil, the spores of which required 
five and a half to six hours’ exposure to streaming 
steam for their destruction. These spores survived 
exposure for three-quarters of an hour in steam under 
pressure at from 109° to 113° C. They were de- 
stroyed, however, by exposure for twenty-five minutes 
in steam at 113° to 116° C. and in two minutes at 
127° C. 
The resistance of spores to moist heat is tested by 
suspending cover-glasses upon which the spores (an- 
thrax) have been dried in little gauze bags in a boiling 
steam sterilizer. The cover-glasses are removed from 
minute to minute and laid upon agar plates, which are 
then placed in the incubator at 37°C. Anthrax spores 
are obtained by carefully removing sporulating streak 
cultures on agar and heating the emulsion prepared 
with a little water to 70° C. for five minutes. 
_ In the practical application of steam for disinfecting 
purposes it must be remembered that while steam under 
pressure is more effective than streaming steam it is 
scarcely necessary to give it the preference, in view of 
the fact that all known pathogenic bacteria and their 
spores are quickly destroyed by the temperature of 
boiling water, and also that ‘‘ superheated’’ steam is 
less effective than moist steam. When confined steam 
in pipes is ‘‘ superheated ”’ it has about the same germi- 
