HALOID ELEMENTS UPON BACTERIA. 177 
taining at least four volumes per cent of this gas in the presence of 
moisture.” 
Chlorine.—The haloid elements are active germicidal agents, 
especially chlorine on account of its affinity for hydrogen, and the 
consequent release of nascent oxygen when it comes in contact with 
microérganisms in a moist condition. And for the same reason this 
agent isa much more active germicide in the presence of moisture 
than in a dry condition. The experiments of Fischer and Proskauer 
showed that when dried anthrax spores were exposed for an hour in 
an atmosphere containing 44.7 per cent of dry chlorine they were not 
destroyed ; but if the spores were previously moistened and were ex- 
posed in a moist atmosphere for the same time, four per cent was 
effective, and when the time was extended to three hours one per 
cent destroyed their vitality. The anthrax bacillus, in the absence of 
spores, was killed by exposure in a moist atmosphere containing 1 
part to 2,500, the time of exposure being twenty-four hours, and the 
same amount was effective for Micrococcus tetragenus ; the strepto- 
coccus of erysipelas and the micrococcus of fowl cholera were killed in 
three hours by 1:2,500, and in twenty-four hours by 1:25,000. The 
bacillus of mouse septiceemia and the tubercle bacillus were killed in 
one hour by 1 : 200. , 
In the writer’s experiments (1880) four children were vaccinated 
with virus from ivory points which had been exposed for six hours in 
an atmosphere containing one-half per cent of chlorine; also with 
four points, from the same lot, not disinfected. Vaccination was un- 
successful in every case with the disinfected points, and successful 
with those not disinfected. Koch found that anthrax spores failed 
to grow after twenty-four hours’ exposure in chlorine water. In 
the experiments of De la Croix to determine the antiseptic power of 
this agent, it was found that when present in unboiled beef infusion 
in the proportion of 1: 15,600 no development of bacteria occurred. 
Miquel gives the antiseptic value of chlorine as 1 : 4,000. 
Chloroform.—Immersion for one hundred days in chloroform 
does not destroy the vitality of anthrax spores (Koch). This agent 
is without effect on the virus of symptomatic anthrax (Arloing, 
Cornevin, and Thomas). Salkowski found that the anthrax bacillus 
in the absence of spores, and the cholera spirillum, were killed by 
being immersed in chloroform water for half an hour. Kirchner 
reports still more favorable results. In his experiments a one-per- 
cent solution killed the cholera spirillum in less than a minute, and 
a one-quarter-per-cent solution in an hour. But the typhoid bacillus 
required at least one-half per cent acting for an hour. 
Iodine.—In the writer’s experiments (1880) iodine in aqueous 
solution with potassium iodide was found to be fatal to Micrococcus 
12 
