THE ACTIVE FORCES OF LIVING ORGANISMS 55 



by one-quarter, at 5,500 metres by one-half, and at 

 9,500 metres by three-quarters.* For every 1,000 

 feet of ascent the barometric pressure falls, roughly 

 speaking, 1 inch, although in reality the fall is 

 slightly greater at low levels than at high ones. 



The general effects of ascending suddenly to a Mountain 



. sickness. 



height at which mountain sickness supervenes in its 

 acute form are loss of bodily strength, helplessness, 

 a feeling of sickness, vomiting, a bluish coloration 

 of the skin, tingling of the ears, disturbed vision, 

 breathlessness, palpitation, and fainting. t It is 

 related that when cats are taken up into the moun- 

 tains above a certain height they succumb after 

 violent epileptic attacks. On human beings, how- 

 ever, the effects of high altitudes are very variable. 

 The monks living at the monastery on Mount 

 St. Bernard, which is 8,117 feet above the sea, 

 become asthmatic ; on the other hand, Potosi,t in 

 America, is 3,960 metres above sea-level, and at one 

 time had a population of 160,000 ; whilst Quito, 

 Bogota, and Micuipampa are all above a height of 

 8,500 feet. On the Ibi Gamin, in Thibet, the brothers 

 Schlaginweit attained a height of 22,230 feet without 

 any other ill-effect than great fatigue. § 



There are few problems even in physiology which 

 present greater difficulties than that of the effects of a 

 rise in altitude, the discussion of which has yielded 



* Plammarion, ' L'Atmosphfere,' p. 72. 



f Mosso, loc. cit., p. 229. 



X Ibid., p. 189. § Ibid., p. 230. 



