228 Historical 



And yet, it appears from his letter to his brother 40 that the 

 same symptoms attacked him on the summit of Antisana, where, 

 however, analysis showed them the normal proportion of 0.218 of 

 oxygen in the air. 



But when, in 1837, 50 he refers to the details of his account, he 

 no longer speaks of the chemical composition of the air, but only 

 of the lessened quantity of oxygen in the same volume; further- 

 more, he introduces into science a new explanation of the fatigue 

 on mountains, an unsatisfactory explanation, which, however, was 

 long accepted without contradiction: 



According to the present state of eudiometry, the air seems as 

 rich in oxygen in these lofty regions as in the lower regions; but in 

 this rarefied air, since the barometric pressure is less than half what 

 we are ordinarily exposed to on the plains, a smaller quantity of 

 oxygen is received by the blood at each aspiration, and we understand 

 perfectly why a general feeling of weakness would result. This is 

 not the place to inquire why this asthenia, on the mountains as in 

 vertigo, usually causes uneasiness and a desire to vomit, nor is it the 

 place to demonstrate that the issue of blood or bleeding from the lips, 

 the gums, and the eyes, not experienced by everyone at such great 

 heights, can by no means be explained satisfactorily by the progressive 

 removal of a mechanical counterweight which compresses the vascular 

 system. It would be better to examine the probability of the effect of 

 a lessened air pressure upon weariness when the legs are moving in 

 regions where the atmosphere is greatly rarefied; since, according to 

 the memorable discovery of two clever scholars, MM. Guillaume and 

 Edouard Weber, the leg, attached 51 to the body, is supported when it 

 moves, only by the pressure of the atmospheric air. (P. 419.) 



If M. Gay-Lussac, who on September 16, 1804, reached the prodi- 

 gious height of 21,600 feet, which consequently was between that of 

 Chimborazo and Illimani, did not suffer from bleeding, perhaps that 

 should be attributed to the absence of all muscular movement. (P. 

 418.) 



About this time, a French physician, Dr. Junod,"' 2 conceived and 

 carried out the idea, already glimpsed by Gondret, of lowering the 

 pressure artificially in apparatuses large enough to accommodate a 

 man. 



M. Junod had been led to make his experiments by the effects 

 "he felt from the expanded air in the Alps, in the Pyrenees, and 

 on Mount Etna. His apparatus consisted of a copper sphere 1.30 

 meters in diameter, in which a man could sit: 



When a person is placed in the interior of the receiver, and the 

 natural pressure of the air is lessened one-quarter, this is what one 

 observes: 



1. The membrane of the tympanum is distended, which causes a 



