998 Summary and Conclusions 



convinced that if Dr. Stoliczka could have breathed oxygen from 

 time to time, he would not have perished thus in two days. 



Whatever the difficulties of practical realization, it is certain 

 that, by the respiration of super-oxygenated air, the summit of 

 Mount Everest, the loftiest mountain of the globe (8840 meters), 

 is no longer theoretically inaccessible to man, since I myself with- 

 out impediment have reached the pressure of 248 millimeters, which 

 corresponds exactly with that of this prodigious height. Now at 

 this level Glaisher fell inanimate in the bottom of his basket, and 

 Croce-Spinelli and Sivel died 200 meters lower. 



3. Dwellers in High Places. 



We have seen in the first part of this book that human habita- 

 tions are found at the level of 4500 meters in South America and 

 the Himalayas; on the summit of Pichincha (4860 meters) hum- 

 ming-birds are numerous; the lapwing "seems at home" at 5500 

 meters on the high plateaux of Little Thibet. These are extreme 

 limits. Lower, between 2000 and 3000 meters, millions of men live 

 grouped in cities and nations, in conditions where dwellers on the 

 seashore almost always feel painful, sometimes unendurable, effects, 

 when they are suddenly transported there. Finally, on hills of 

 about 1000 meters, not only are there large populations, but the 

 dwellers on the seashore usually feel — at least for a time — more 

 active, more nimble, and stronger there than in their native haunts. 



Let us examine successively these different points. 



Slight heights. — We place their upper limit at about 2000 meters. 

 The impression which they produce upon the traveller who comes 

 to stay there for several weeks or months is, as we have just said, 

 generally favorable. Let us refer to what we said of the aeronaut 

 carried by his balloon to a corresponding level; the same observa- 

 tions will apply to our traveller. There should be first a tendency 

 to a decrease of the blood oxygen, a decrease for which the accelera- 

 tion of the respiration and the circulation will probably provide 

 sufficient compensation. These accelerations are real, as the obser- 

 vations of M. Jaccoud (p. 297) and M. Vacher (p. 960-1) prove. The 

 respiration even becomes more ample, "so as to set to work certain 

 indolent regions of the lungs which ordinarily take only a very 

 small part in the inspirational expansion; these regions are the 

 upper parts of the organs." According to Dr. Armieux (p. 298-9) , 

 the result is a considerable increase of the thoracic capacity, whose 

 circumference gains an average of 2 to 3 centimeters. Now this 

 increased amplitude of respiratory movements is of great impor- 



