~ Sir Humphry Davy. WS 
been proposed, founded on the deadly effects of this gas on small an- 
mals, that here was at length discovered the principle of the plague 
itself !* 
The sufferings which our young philosopher voluntarily inflicted on 
himself, in prosecuting these researches on the respiration of the 
gases, remind us of Spallanzani’s experiments upon the gastric 
juice; while the dangers he encountered carry our minds back to 
Pelletier, who lost his life in the audacious attempt to breathe oxy- 
muriatic acid gas. It was deemed necessary to compare the ef- 
fects of nitrous oxide with those of common stimulants, both to as- 
certain its relation to them, and its tendency either to increase or to 
diminish their effects upon the system. With this view he submitted 
himself to excessive intoxication, so extreme as to produce distressing 
and alarming symptoms.} T° ascertain the effects of an atmosphere 
containing large portions of the same gas, he enclosed himself in a 
box, and at three successive intervals for an hour and a quarter (dur- 
ing which ‘time he remained in the box) had sixty quarts of the 
gas thrown into the box, finally constituting a large proportion of 
the air within. When the last twenty quarts were thrown in, his 
emotions became similar to those usually experienced by a mod- 
erate dose of the pure gas; but not satisfied with this, immediately 
after coming out of his cage, he began to respire twenty quarts 
unmingled nitrous oxide. As this was probably the most effectual 
trial ever made of this wonderful agent, the consequences are worth 
remarking, as detailed in the expressive terms of the adventurous ex- 
perimenter. “A thrilling (he observes) extending from the chest to 
the extremities, was almost immediately produced. I felt a sense of 
tangible extension highly pleasurable in every limb; my visible im- 
pressions were dazzling and apparently magnified ; I heard, atin. 
ly, every sound in the room, and was perfectly aware of my situation. 
By degrees, as the pleasurable sensations imereased, I lost all con- 
nection with external things; trains of vivid visible images copy 
passed through my mind, and were connected. with wot a such @ 
manner, as to produce perceptions perfectly novel. I existed in a 
world of newly connected and newly modified ideas. I theorised 5 
T imagined that I made discoveries. When I was awakened from 
this semi-delirious trance by Dr. Kinglake, who took the bag from 
my mouth, indignation and pride were the first feelings produced by 
* Researches, p. 453. 1 Ib. 481. 
