— 303 — 



the gas says : " The air of an apartment may be char-, 

 ged with a sufficient quantity of this gas to have an ex- 

 tremi'iy disagreable otlour, without being injurious to 

 those who breathe it. But if the gas is more abundant, 

 it produces an inflammation of the tranrhes and lungs 

 difficult to cure, and when respired in still greater pro- 

 portion it causes instantaneous death. Thenard states 

 that birds perish in air which does not contain more 

 than lilSOOth of this volume, and that a dog lost its 

 life whm the air contained IjSth per cent. 



As the air of towns even when in the most sanitary 

 condition, rarely, if ever has so strong an odour as that 

 mentioned by Berzelius ; and as I have already proved 

 by experiment, that by far the greater part of the bad 

 odour arising from putrescent animal and vegetable 

 matters depends, not, on the sulphuretted hydrogen, but 

 on volatile organic matter carried up Avith ammonia 

 and other gases ; it is suffi'^iently evident that but a 

 small portion of the malificent effects of the putrid 

 emanations can be referred to sulphuretted hydrogen. 



Again some writers have spoken of excess of carbon- 

 ic acid gas in the atmosphere resulting from the ex- 

 trication of this gas from putrefying substances, as a 

 cause of disease. TViis opinion is liable to still stronger 

 objections, than that of sulphuretted hydrogen ; fur in 

 the first place carbonic acid is a natural constituent of 

 the atmosphere, which, in its natural condition con- 

 tains almost l|1000lh of its volume, and it is we'l as- 

 certained that although a positive poison it may be 

 respired without danger Avhen sufficiently diluted with 

 atmospheric air. Lequin, for example, found that air 

 containing l[13th of its vo'ume of carbonic acid pro- 

 duced when respired scarcely any perceptible effect ; 

 when containing lilOth it caused oppresrion of the 

 chest and irritation of lungs ; but when augmented to 

 l[yth or li4th it produced asphyxia. In like manner 

 Girtouner and Beddoes caused consumptive patients to 

 breathe air containing one-thirteenth of its volume of 

 this gas as a remedial measure. The small additional 

 quai.tily of carbonic acid to the atmosphere cannot, 

 therefore be viewed as an important cause of disease. 

 The same remarks are applicable to carbouetted apd 



