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duce a spark to run the risk of the explosion which would almost surely 
follow. The writer has personally experienced the formation of such 
a spark when turning off a light, and it very frequently occurs when 
turning it on. The danger from gas and are lights is too apparent 
to need more than mention. It would be a matter of courtesy as well 
as a measure of safety to inform occupants of adjoining rooms of the 
nature of the work being done and the need for care in regard to fire 
should the fumes find entrance to their establishments. An additional 
safeguard would be to station a watchman on the premises till the 
treatment is ended. The danger to the operator making the exposure 
is but slight if he knows the nature and effects of the gas. As soonas 
he finds that he is being overcome and getting dizzy, he should at once 
get out into the open air. 
EFFECTS OF THE GAS UPON THE OPERATOR. 
The first appreciable effect is upon the sense of smell. At first the 
fumes have an extremely disagreeable odor; but the odor soon seems 
to gradually disappear, and in this treatment the men strongly doubted 
that they were using the same substance with which they began. This 
deadening of the smell continues until it iscomplete. The other senses 
seem to become benumbed simultaneously, so that the operator does 
not feel or realize that any change is taking place in him. But the 
heart beat becomes more and more rapid as the supplv of oxygen in 
the lungs diminishes. The power of thought is very much weakened 
and the work is continued in a mechanical sort of way. Hearing and 
sight are also weakened; in fact, consciousness itself is being gradually 
lost. But before this weakening process has gone far enough to be 
really dangerous or injurious the operator feels rather ‘‘ queer” in the 
head, with more or less dizziness. There is no pain or disagreeable 
sensation, no desire to escape out of it, and no sense of suffocation. 
But when a person reaches this condition it is high time to get out 
into the open air, where the ill effects will soon disappear. Should the 
operator persist in remaining longer in the room after this condition 
is reached there would be danger of a fall; and if no one happened to be 
near, his presence might not be missed and suffocation would soon 
follow. Even if he should get out safely the after effects would be 
more serious and a severe headache, at least, result. It should be 
clearly understood, however, that the action of the gas is somewhat 
poisoning as well as suffocating. These observations concerning the 
effects of the gas upon the men are gathered from personal expe- 
rience and the statements of others engaged in making the treatment 
herein reported. 
Owing to the effect of the gas upon the action of the heart, the 
writer believes that it would be wise to caution persons having any 
4670—No. 30—01——6 
