Symptoms of Decompression 693 



B: With 15.3 per cent of oxygen, breathing is continuous and 

 not very difficult. 



C: With 9.8 per cent of oxygen, the air is asphyxiating, and at 

 the end of one or two minutes, fainting fits occur. M. Leblanc, 

 who went in suddenly, almost fainted, and the master miner who 

 accompanied him was seized by vertigo and nausea. 



Now, in observation A, the oxygen tension equals that existing 

 in pure air at 60.4 cm. of pressure; which corresponds to a height of 

 1800 meters. For observation B, the equivalent pressure is 55.3 

 cm., and the altitude 2500 meters. For C, the pressure is 35.4 cm., 

 and the altitude 6000 meters. 



It is absolutely certain that a dweller in the plains, suddenly 

 transferred to heights of 1800 and particularly 2500 meters, and 

 driven immediately to the hard work of miners, would, like them, 

 find the air weak and breathing rather difficult. It is absolutely 

 certain that an aeronaut who was transferred to a height of 6000 

 meters as suddenly as in the observation of M. Leblanc and who, 

 like this chemist, tried to make the effort necessary to climb a 

 slope and empty a flask full of mercury, would also experience 

 decidedly serious symptoms. 



Finally— the last resemblance to which we shall call attention 

 —the strange rapidity with which rigor mortis appears in animals 

 dying in rarefied air is found also in death by asphyxia, when the 

 carbonic acid formed is eliminated by absorbing it with potash. 

 Example: 



Experiment CCL. March 20. At 3 o'clock, a finch is placed under 

 a bell of 3 liters on a tripod which isolates it from a crystallizing pan 

 full of a potash solution. An elbow tube connects this bell with an- 

 other which rests on the water basin, and in which the water will 

 rise proportionately with the absorption of CO., so that the pressure 

 will always remain the same. 



At 4 o'clock, the bird, which was a little uneasy at the beginning, 

 lies down and remains quiet; pants. 



It dies at 6:23; rectal temperature 31°. 



Rigidity begins in the wings at 6:34; it is complete at 6:45. 



Our parallel between the symptoms of decompression and those 

 of asphyxia is therefore complete, and continues even to the least 

 details with remarkable precision. 



In both cases, the whole thing is summarized in this formula: 

 nutritional disturbances due to the introduction into the organism 

 of an insufficient quantity of oxygen in a given time. 



