ASPHYXIA 



137 



by breathing in a confined space. There are here several points that 

 present themselves for consideration. The effect of respiration on the 

 air is to take away a certain proportion of oxygen and to add certain 

 matters regarded as deleterious. The emanation which commonly has 

 been considered as having the most decided influence on the system is 

 carbon dioxide ; but this has been much overestimated. In death from 

 charcoal-fumes, carbon monoxide is the poisonous agent. Regnault and 

 Reiset exposed dogs and rabbits for many hours to an atmosphere con- 

 taining twenty-three per cent of carbon dioxide artificially introduced, 

 and between thirty and forty per cent of oxygen, without ill effects. 

 They took care, however, to keep up a free supply of oxygen. 



These experiments are at variance with results obtained by others ; 

 but Regnault and Reiset explained this difference by the supposition 

 that the gases in other observations were impure, containing chlorin or 

 carbon monoxide. This view is sustained by the experiments of Bernard 

 with carbon monoxide. In animals killed by this gas, the blood, both 

 venous and arterial, is of a bright red color, which is due to the fixation 

 of the gas by the blood-corpuscles. In this way, the red corpuscles are 

 paralyzed and the animal dies from asphyxia. 



In breathing in a confined space, the distress and the fatal results 

 are produced, in all probability, more by animal emanations and a defi- 

 ciency of oxygen than by carbon dioxide. When the latter gas is 

 removed as fast as it is produced, the effects of diminution in the pro- 

 portion of oxygen are soon very marked, and they progressively increase 

 until death occurs. The influence of emanations from the lungs and 

 general surface is considerable ; and this fact, which almost all have 

 experienced more or less, has been illustrated in instances of large num- 

 bers of persons confined without proper change of air. 



In crowded assemblages, the slight diminution of oxygen, the eleva- 

 tion of temperature, increase in moisture, and particularly the presence 

 of organic emanations combine to produce unpleasant sensations. The 

 effects of this carried to an extreme degree were exemplified in the 

 confinement of the one hundred and forty-six English prisoners, for 

 eight hours only, in the " Black Hole of Calcutta," a chamber eighteen 

 feet (5.486 meters) square, with only two small windows, and these 

 obstructed by a veranda. Out of this number, ninety-six died in six 

 hours, and one hundred and twenty-three, at the end of the eight hours. 

 Many of those who immediately survived died afterward of putrid 

 fever (Annual Register, 1758). The incident of the "Black Hole of 

 Calcutta " has frequently been repeated on emigrant and slave ships, 

 by confining great numbers in the hold of the vessel, where they were 

 entirely shut off from the fresh air. 



