or the same gas as is produced during the combustion of carbon or coke in a limited supply of oxygen.
These researches led me to study the action of this gas in its pure form, and to the discovery of many curious facts relating to it. Among other things, I noticed that, like oxygen, it made the venous blood of a bright-red color, and that warm-blooded animals exposed to it for a long period of narcotion are rendered temporarily diabetic.
I did not, on the whole, think it commendably safe as an anæsthetic for man, but I fixed upon it at once as one of the best and cheapest of lethal agents for the painless destruction of life in the lower creation. It is the principal agent for this purpose which I have used since the date named above, 1854.
Carbonic oxide is a gas, and, if quite pure, is so odorless and produces so little irritation that, when present in the air, it is apt to be breathed unconsciously until the effects of it are felt. Those who by accident have been narcotized by it, and have recovered from the effects, have expressed that they had no recollection of anything whatever, that they passed into sleep in the ordinary way of sleeping, and knew no more.
Chloroform.—I was naturally led to chloroform, by reason of its common use as an anæsthetic. There is no anæsthetic more certain in its action, and none more certain to kill if it be administered in a determinate manner. Administered even with skill, so as not to kill, it proves accidentally fatal about once in twenty-five hundred times, and, so soon as air is charged with over five per cent of its vapor, it is not breathed without danger. Death from it is very determinate when it occurs, and seems to be entirely painless. The vapor of chloroform does not burn; on the contrary, it extinguishes flame. If we plunge a lighted taper into a jar through which the vapor of chloroform has been diffused, the light is at once extinguished. When we use it for narcotism, we merely diffuse the fluid into the state of vapor, and make provision for the vapor to be absorbed by the lungs of those subjected to it. It produces little irritation when breathed.
Bisulphide of Carbon.—The bisulphide of carbon is a very rapidly acting anæsthetic. It produces narcotism, in fact, almost as quickly as carbonic oxide, and with less muscular commotion. The vapor of it burns in air if a light be brought near to it; but, when its vapor is mixed with that of chloroform, this danger is avoided. It is bought as chloroform is, in the fluid state, and can be obtained, therefore, from the chemist directly, ready for use, by diffusion of its vapor. It has one immense advantage, that of being excessively cheap; and it has one great disadvantage, that of being excessively unpleasant in regard to its odor, unless it be most carefully purified by repeated distillations. Combined with chloroform, with which it mixes freely, the peculiar odor is largely reduced, and, by pouring the mixture over chloride of lime, is almost entirely removed. For this reason, together
