THE AIR AND LIFE. 533 



acid and taken from another animal of the same species. It also pro- 

 duces insensibility when locally applied to the skin, n form of anaes- 

 thesia that has been long known and frequently utilized. Indeed, 

 Pliny tells us, in his Natural History, that marble and vinegar benumb 

 the parts to which they are applied, so that these may be cut or cau~ 

 terized without causing pain. In this case the anaesthetizing agent is 

 the carbcmic acid set free by the action of the acetic acid of the vinegar 

 on the carboiuite of lime. 



When carbonic acid acts ui>on the entire organism, instead of on a 

 portion of it, as when inhaled into the lungs, it brings about a general 

 anaesthesia which has been investigated by several scientists. One of 

 these, M. Ozanam, was so well pleased with the result that he did not 

 hesitate to recommend that carbonic acid be used for an anaesthetic 

 instead of ether or chlorolbini. So far as we know his advice has not 

 beenfollowed and it isunlikely that surgeons will ever avail themselves 

 of so dangerous an agent. Yet a number of cases are known where men 

 were thoroughly infected with carbonic acid without suffering death. 

 In all such cases, there has been complete anaesthesia, before which, 

 as reported by some of the i^atients, they passed through a most enchant- 

 ing stage, when they fancied themselves in the midst of enrapturing 

 music and refulgent light. But this stage is soon followed by absolute 

 loss of consciousness, and if the poisonous agent continues to i)ervade 

 the blood or fails to separate from it, everlasting sleep is the result. 

 Accidental deaths caused by carbonic acid are not rare, and have 

 been noted wherever alcoholic fermentation runs its course as in brew- 

 eries and wine vaults, and where there is a natural or artificial emis- 

 sion of carbonic acid gas as in caves or in close or poorly ventilated 

 rooms crowded with men or animals. The air in public halls becomes 

 rapidly vitiated. As much as 10 ]>arts of carbonic acid per thousand 

 have been found in theaters, in schoolrooms, and in lecture-halls, and 

 in a crowded stable on the Al})s tlic proportion was as great as lil parts 

 of carbonic acid in 1 000 i)arts df air. Atmospheres of this description 

 are poisonous, as has been proved. Thus, during the war in India, 14G 

 prisoners were confined in a small room at 8 o'clock in the evening. 

 At 1* in the morning only 50 were living, and at <laybreak there 

 remained only 23, and these were inadyingcondition. In likenumner, 

 out of 300 prisoners locked in a poorly ventilated cellar after the battle of 

 Austerlitz 200 were suffocated by carbonic acid after a few hours. A 

 similar accident happened at the celebrated assizes of Oxford, when the 

 judges and a portion of the audience were suffocated through the same 

 agency. It may be that in those cases the infiuenceof another poison, 

 which in the opinion of M. Brown Sequard, is exhaled from tlie lungs, 

 was superadded to that of the carbonic acid; but it nuist be c(mceded 

 that the existence of such a poison is by no means certain although 

 it seems i^robable. To return to cases of suffocation b}^ carbonic 

 acid, we may mention those in which men and animals are killed by 

 gas that, after flowing from natural springs, accumulates in neighbor- 



