ASPHYXIA. 493 



removed, will gradually consume oxygen, until, when death 

 occurs, the proportion is reduced to from 3 to 5 parts per 

 100. 1 When the carbonic acid is allowed to remain, the 

 increased density of the atmosphere interferes with the dif- 

 fusion between the gases of the blood and the air, and death 

 supervenes with greater rapidity. 



The influence on animals of emanations from the lungs 

 and general surface, from which the carbonic acid and watery 

 vapor have been removed, has been shown by Dr. Hammond 

 to be very decided and rapid. He confined a mouse in a 

 large glass jar, so arranged as to admit fresh air as the at- 

 mosphere became rarefied by respiration, causing the carbonic 

 acid to be absorbed by sponges saturated with baryta-water, 

 and the watery vapor by pieces of chloride of calcium. The 

 animal died in forty-five minutes ; when, by passing the gas- 

 eous contents of the jar through baryta-water, it was shown 

 to contain no carbonic acid, and the presence of organic 

 matter in large quantity was demonstrated. 2 



In crowded assemblages, the slight diminution of 

 oxygen, the elevation of temperature, increase in moisture, 

 and particularly the presence of organic emanations, com 

 bine to produce unpleasant sensations. The terrible ef- 

 fects of this carried to an extreme were exemplified in the 

 confinement of the 146 English prisoners, for eight hours 

 only, in the "Black Hole" of Calcutta; a chamber eigh- 

 teen feet square, with only two small windows, and those 

 obstructed by a verandah. Out of this number, 96 died in 

 six hours, and 123 at the end of the eight hours. Many of 



1 BERNARD, Lemons sur les Effets des Substances Toxiques et Hedicamcntemcs, 

 Paris, 1857, p. 116. 



3 Op. cit., p. 1*70. "For the detection of organic matter in the atmosphere, 

 the permanganate of potassa affords a very sensitive reagent. A solution of this 

 substance in water loses its brilliant red color, and the salt undergoes decompo- 

 sition, when air containing organic matter is passed through it. By the extent to 

 which the loss of color reaches we are enabled to form an approximative idea of 

 the amount of such matter present in the air. The solution is placed in Liebig's 

 bulbs, and the air is drawn through it by means of an aspirator." P. 172. 



