DESTRUCTION OF BACTERIA BY CHEMICALS. 159 
exposed for ninety-six hours in a disinfecting chamber 
to the action of SO, in the proportion of from 4 to 6 
per cent. by volume were not destroyed. In the ab- 
sence of spores, however, the anthrax bacillus in a 
moist condition, attached to silk threads, was found 
by Sternberg to be destroyed in thirty minutes in an 
atmosphere containing 1 volume per cent. As the re- 
sult of a large number of experiments with SO, as a 
disinfectant it has been determined that an ‘‘ exposure 
for eight hours to an atmosphere containing at least 
4 volumes per cent. of this gas in the presence of moist- 
ure’’ will destroy most if not all of the pathogenic 
bacteria in the absence of spores. 
Peroxide of Hydrogen (H,O,) is an energetic disin- 
fectant, and in 2 per cent. solution (about 40 per cent. 
of the ordinary commercial article) will kill the spores 
of anthrax in from two to three hours. A 20 per cent. 
solution of a good commercial hydrogen peroxide solu- 
tion will quickly destroy the pyogenic cocci and other 
spore-free bacteria. It combines with organic matter, 
becoming inert. It is prompt in its action and not 
poisonous, but apt to deteriorate if not properly 
kept. 
Chlorine is a powerful gaseous germicide, owing its 
activity to its affinity for hydrogen and the consequent 
release of nascent oxygen when it comes in contact with 
micro-organisms in a moist condition. It is, there- 
fore, a much more active germicide in the presence of 
moisture than in a dry condition. Thus, Fischer and 
Proskauer found that dried anthrax spores exposed for 
an hour in an atmosphere containing 44.7 per cent. of 
dry chlorine were not destroyed; but if the spores were 
previously moistened and were exposed in a moist 
