22 
POPULAR SCIENCE REVIEW. 
Modern Agents eor Anesthesia. 
The original chemical bodies, nitrous oxide gas and sulphuric 
ether, have, notwithstanding much opposition and many ad- 
vancements of rivals, retained a certain fair position as an- 
aesthetics. Nitrous oxide, indeed, has of late been greatly 
extolled and raised into fervour of favour by the members of 
the Dental profession. Ether has been persistently employed 
in some parts of America and some parts of France, and its 
friends have quite recently claimed for it that it has not been 
the cause of one single death. 
It is right that the members of the public, who, in common 
parlance, know only that sometimes they or theirs may have to be 
put “ under chloroform,” should know these and all other facts 
correctly, and intelligently ; should know what agents are used 
and the relative value of each agent in respect to practicability 
of administration, certainty of action, and freedom from risk. 
I will essay, therefore, to bring these points clearly forward, not 
hurriedly and not with such exceeding brevity as to lose myself 
in obscurity. 
Of the various agents that may fairly come under considera- 
tion, I will confine what has to be said, in the first instance, to 
substances which produce general insensibility, and of these I 
will name none that have not been tried, and for some valid 
reason or other been found wanting in some essential quality. 
Nitrous oxide and sulphuric ether, in their respective ways, 
represent what are considered to be the physical requirements 
of agents for the production of anaesthetic sleep. The idea now 
is well nigh universal, that the agent must either be a gas, as 
nitrous oxide is, or a liquid very easily transformable into 
vapour, as ether is. These, I say, are conceded points, and are 
based on the belief that the best and readiest mode of producing 
the general sleep of insensibility, is letting the narcotic enter 
the system by the channel of the lung ; by presenting to the 
blood as it flows over the lung from the right to the left side of 
the heart, some substance which the blood will absorb and will 
carry direct to the nervous centres in quick and steady stream. 
It is true we can produce the effect we want in another way, by 
another mode of entrance. For example, I have recently found 
it quite possible and easy to put an animal profoundly under 
chloroform, by inserting that substance, in its fluid state, beneath 
the skin with a fine needle, and this method could be applied 
to any soluble narcotic ; but as a general principle, it is not so 
good a method as that of administering by what is called “ in- 
halation.” 
We may put, therefore, in classification all the modern agent 
