106 
ON CHLOROFORM. 
youth, who was recommended to him to conduct his chemical pro- 
cesses, and who with great boldness investigated the physiological 
properties of various gases by trying experiments on himself. 
From these experiments resulted the discovery of the curious pro- 
perties of nitrous oxide gas. These were giddiness, a delightful 
sense of thrilling in the chest and limbs, acuteness of hearing, 
brilliancy of all surrounding objects, and an unconquerable propen- 
sity to muscular exertion or laughter; these were of short duration, 
and were not followed by the depression and nausea consequent 
on the use of spirits or opium. The effects, however, were not 
uniform, some persons having been affected with weakness, ten- 
dency to faint, loss of voice', and insensibility. In fact, its effects 
vary, not only from differences of constitution in various indivi- 
duals, but also according to the quantity inspired ; and, as in the 
case of the substances immediately to be noticed, insensibility and 
unconsciousness always result if it be taken in sufficient quantity. 
It has been long known, though perhaps not very generally, 
that the vapour of ether possesses similar properties to nitrous ox- 
ide. At what time this was first observed I am not aware ; but 
the earliest notice I have found of it is in “The Quarterly Journal 
of Science” for 1818: — 
“ When the vapour of ether mixed with common air is inhaled, 
it produces effects very similar to those occasioned by nitrous oxide. 
A convenient mode of ascertaining the effect is obtained by intro- 
ducing a tube into the upper part of a bottle containing ether and 
breathing through it : a stimulating effect is at first perceived at 
the epiglottis, but soon becomes very much diminished ; a sensation 
of fulness is then generally felt in the head, and a succession of 
effects similar to those produced by nitrous oxide. By lowering 
the tube into the bottle, more of the ether is inhaled at each inspi- 
ration, the effect takes place more rapidly, and the sensations are 
more perfect in their resemblance to those of the gas. 
“ In trying the effects of the ethereal vapour on persons who are 
peculiarly affected by nitrous oxide, the similarity of sensation 
produced was very unexpectedly found to have taken place. One 
person, who always feels a depression of spirits on inhaling the 
gas, had sensations of a similar kind produced by inhaling the 
vapour. 
“It is necessary to use caution in making experiments of this 
kind. By the imprudent inspiration of ether, a gentleman was 
thrown into a -very lethargic state, which continued, with occa- 
sional periods of intermission, for more than thirty hours, and a 
great depression of spirits. For many days the pulse was so much 
lowered that considerable fears were entertained for his life.” 
These facts may be noticed as a remarkable instance of how 
