RAREFIED ATMOSPHERE. 305 



there to maintain human life at all for more than a 

 very short period of time. * At even half that height 

 above the sea (say 14,500 feet) however, any form of 

 exertion becomes exceedingly laborious, and the sen- 

 sation of " want of breath" proves quite distressing 

 after very slight exercise ; indeed it is doubtful if human 

 beings could reside at such an altitude, for a perman- 

 ency, as at these heights, on the table-lands and passes 

 of the Andes, as we have before observed, there is 

 a regular disease, to which all dwellers on the plains 

 are subject, known in Spanish as " Puna," which in 

 its severer forms not unfrequently proves fatal, y We 

 have ourselves suffered severely from it. It is the 

 result of exertion undergone in highly rarefied atmo- 

 sphere, which is always felt with peculiar intensity 

 among persons lately arrived from the low-lands. Its 

 effects however diminish, though they never disappear, 

 after such persons have resided for some time at great 

 altitudes. 



The lungs on such occasions appear to be incapable 

 of filling themselves properly with air, and the efforts 

 made to catch breath after exertion become exceedingly 

 laboured, and produce a sensation akin to that of 

 suffocation : while the working of the heart itself when 

 climbing up steep slopes, at great altitudes, may fre- 

 quently be actually heard its action is also accelerated 

 to a high degree, and a great strain is placed upon it. 



* See account of the deaths of Messrs. Croci-Spinelli and Sivel, 

 suffocated in a balloon, April 15, 1875, at an elevation of from 26,000 

 to 28,000 feet by want of air (London Times of April 19, 1875; con- 

 tains complete details, given on p. 7). 



f See observations on a Mountain Sickness " in the Himalayas, in 

 the Himalayan Journals of Sir J. D. Hooker, 1854, Vol. ii., p. 150; 

 also on "Puna," in his Travels among the Great Andes, by Edward 

 Whymper, 1892, pp. 382 to 384, same at pp. 367 to 370. 



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