453 



sulphate of ammonia. In all such cases, as in undue 

 exposure to the disengaged gases of vinous fermentation 

 and charcoal fires in other countries, not only is there an 

 unnatural atmosphere generated, but equivalent volumes of 

 vital air are withdrawn, and an admixture of 35 per cent, of 

 carbonic acid is destructive of life to small quadrupeds in 

 about ten minutes. Experiments, indeed, sufficiently attest 

 the poisonous properties of this gas when applied merely to 

 the skin by immersion in it, the ordinary atmospheric access 

 to the lungs being continued. In its pure state, like the 

 irritant gases, it cannot even be inhaled, and suffocation from 

 choke damp is more difficult of removal by timely resort to 

 appropriate measures than when produced by either hydrogen 

 or azote. Did persons but consider that each adult deterio- 

 rates by his respiration about 800 cubic inches of air per 

 minute, or 180 gallons of it per hour, and each argand gas 

 burner still more, regard would surely be had to some of the 

 simple modes of ventilation adapted to crowded apartments 

 and public buildings beyond the mere fire-place flues. Equally 

 destitute of smell, the carbonic oxide, though perhaps less 

 directly sedative when inhaled with a necessary admixture of 

 atmospheric air, will shortly excite some mucous irritation, 

 weight in the head, dinmess of sight, and giddiness ^ partly 

 from its direct narcotic impression, but mainly, I apprehend, 

 from its inability to decarbonize the blood. 



On the consideration of the other gases, which are chiefly 

 of a corrosive character, we need not just now enter, since, 

 with the exception of ammonia and sulphurous acid, they 

 are not much found free in nature, and have indeed them- 

 selves from time to time been suggested as possessing the 

 powers of disinfection. In common with those already 

 mentioned, they are unable to aerate the blood; but some 

 of them exercise, likewise, even when largely diluted with 

 atmospheric air, an irritant action upon the mucous surfaces. 



