Sir Humphry Davy. 223 



been proposed, founded on the deadly effects of this gas on small an- 

 imals, that here was at length discovered tlw^principle of the plague 

 'itself l"" 



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. f To 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 of 

 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, distinct- 

 ly, every sound in the room, and was perfectly aware of my situation. 

 By degrees, as the pleasurable sensations increased, I lost all con- 

 nection with external things ; trains of vivid visible images rapidly 

 passed through my mind, and were connected with words in such a 

 manner, as to produce perceptions perfectly novel. I existed in a 

 world of newly connected and newly modified ideas. I theorised ; 

 I 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. t lb. 481. 



