THE COMPOSITION OF EXPIRED AIR. 403 



to 14.08, or an average for eight experiments of 13.24 per cent of the 

 air, while the oxygen had diminished to from 3.25 to 5.61, or an average 

 of 4.G7 per cent of the air. The symptoms observed were those pro- 

 duced by insufficiency of oxygen, and there was no evidence that death 

 was due to organic matters in the air. The duration of life in the ani- 

 mals confined was from three to six hours, being much longer than that 

 reported by Hammond, using a slightly smaller vessel, viz, less than 

 one hour, and corresponds to the results reported by Sanfelice (33), 

 who found that the animals lived from six to seven hours. When the 

 experiment was so modified that all the carbonic acid was removed 

 from the air breathed by the animal, the animal did not die in seven 

 hours, although the percentage of oxygen had been reduced to 18.35. 

 These experiments, therefore, furnish no evidence of the existence of 

 an organic poison in the expired air, but the method of absorbing 

 carbonic acid by an alkali is said by Brown-Sequard and d'Arsonval 

 (16) to change the organic poison which they claim to be present, and 

 hence these experiments are not conclusive on this point. 



A series of experiments was also made upon mice and sparrows to 

 determine the time required to produce death by asphyxia when the 

 animal is confined in a jar of known capacity, when no provision is 

 made for removing carbonic acid and moisture, or for supplying fresh 

 air, and also to determine the proportions of carbonic acid and of oxy- 

 gen existing in the inclosed air at the time of death. In connection 

 with these experiments, it was also sought to determine the influence 

 which high or low temperatures of the air would have on the result. 



A mouse weighing 21 grams, placed in ajar of 1,000 c. c. capacity at 

 a temperature of 30° C, lived four hours; in a jar of 2,000 c. c. capacity 

 a similar mouse lived seven and a half hours; in one case when the 

 room temperature was 25.5° C, in another case when the room temper- 

 ature was 5° 0. In the first case, death occurred when the amount of 

 carbonic acid was 12 and that of the oxygen 8.6 per cent of the mix- 

 ture; in the second case, the proportions were 13.2 per cent of carbonic 

 acid and 6.4 per cent of oxygen; and in the third case, 10 per cent of 

 carbonic acid and 9.2 per cent of oxygen. There are considerable dif- 

 ferences in susceptibility to the effects of an impure atmosphere in 

 individual mice, but when a mouse is placed in a closed jar containing 

 ordinary atmospheric air, the time required to produce death is usually 

 that required to produce the proportions of carbonic acid and of oxy- 

 gen indicated above, and, hence, is in proportion to the size of the jar. 

 A mouse should live about twice as long in ajar of 2,000 c. c. as in one 

 of 1,000 c. c, other conditions as to temperature, etc., being the same, 

 and commencing with ordinary atmospheric air. 



The duration of life in the experiments with atmospheric air in closed 

 vessels, making due allowance for variations in the air volume, coin- 

 cides quite closely with the duration of life in the Hammond experi- 

 ment. The air analyses at death of the animals in the two forms of 



