8 
carpet on the floor, but to obtain the effect of the gas upon spores, cul- 
tures of anthrax containing spores were exposed under the same condi- 
tions. The percentage of gas was 1.6 per cent. One hundred and fifty 
cubic centimeters of water were introduced into the room, after the 
combustion of sulphur, in the form of steam. Time, eighteen hours. 
The results were that anthrax exposed under all conditions showed a 
growth. The other organisms were uniformly killed, while all controls 
showed normal growth. 
Experiment No. 4. 
Percentage of gas 4. 25 per cent ; time, sixteen hours. Cultures, 
anthrax, cholera, colon bacillus, diphtheria, typhoid, icteroides, and 
plague, were exposed in envelopes upon the shelf, and floor of the room, 
under carpet, and enveloped under four layers of blanket. Of those 
exposed on the shelf all were killed. Of those exposed under the car- 
pet anthrax grew while the others were uniformly killed. Of those 
enveloped in the blanket anthrax, tyj)hoid and icteroides grew; cholera, 
colon, diphtheria, and plague, were killed. Controls to this experi- 
ment grew uniformly. 
In the experiments involviog the use of a small percentage of gas 
spore-bearing organisms, as anthrax, were not employed, the design 
being to observe the effect of low percentages of the gas upon organisms 
interesting from a quarantine or epidemic point of view. The results 
would seem to indicate that provided a proper quantity of moisture be 
present, even these low percentages are efficient against ordinary patho* 
genic organisms. 
Numerous experiments have been made with various percentages of 
the gas to fulfill the third indication laid down for these experiments, 
namely, to demonstrate the minimum exposure to minimum percentage. 
The results of these experiments have been uniformly to show that, 
while low percentages of the gas have been uniformly efficient as a dis- 
infectiag agent, it has been found impossible to produce germicidal 
effects within any very short period. The times tried have been, respec- 
tively; two hours, four hours, six hours, eight hours, twelve hours, 
fourteen hours, and sixteen hours. Sixteen hours, as has been shown 
above, have given good results with comparatively low percentages of gas, 
but uniform germicidal effects have not been obtained under this time. 
This would seem to indicate that a certain time is necessarv to allow the 
K/ 
gas to penetrate and remain in contact with the organisms which it is 
designed to destroy, but, above all, the experiments have demonstrated 
that it is possible to employ the gas as a germicidal agent in" much 
lower percentages and for considerably shorter term of exposure than is 
now required by the regulations of the Treasury Department of the 
United States. Four and one-quarter per cent has been the maximum 
quantity of gas used ; twenty-four hours the longest time. While the 
time may have been shortened materially by the employment of this 
