Chapter I 

 DECREASED PRESSURE 



Subchapter I 



OBSERVATIONS, THEORIES, AND RECENT 

 DISCUSSIONS 



The principal results of the experiments reported in the second 

 part of this book, and the theory drawn from them in regard to the 

 influence of high elevations were submitted to the judgment of the 

 public several years ago. 1 The idea that symptoms produced by a 

 sojourn in rarefied air, particularly mountain sickness, are caused 

 solely by the lessening of the oxygen tension in the air, and are in 

 fact only a form of asphyxia, has aroused much criticism, generally 

 not very instructive, which it would be tedious to reproduce here. 



Among those who took it upon themselves to oppose my conclu- 

 sions, some seem not to have an exact knowledge of them, and 

 particularly not to have read the experiments on which they are 

 based. For instance, M. Bouchut 2 wrote the following lines in 1875: 



One might question whether it is really the diminution of the 

 oxygen of the blood that causes mountain sickness, and not rather 

 a carbonhemia due to the accumulation of carbonic acid in the blood, 

 which dulls the organs and disturbs their functions; but that makes 

 no difference in the fact itself, which is incontestable. In my opinion, 

 and according to my experiments, the nervous phenomena of asphyxia 

 are all due to the dulling action of the carbonic acid retained in the 

 blood. In fact, I have demonstrated that all animals that die asphyx- 

 iated for want of oxygen have previously a more or less pronounced 

 anesthesia, and I am surprised that aeronauts have not announced 

 this fact, since it is so easy to verify it on a mammal placed beneath 

 the receiver of an air pump. 



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