142 - Historical 



this acting first in me upon the digestive tract, caused a disturbance 

 in the digestion, of which the headaches were evidently the conse- 

 quence. (P. 259.) 



The following observations corroborate the first explanation 

 given by Jacquemont: 



August 11, 1830, I reached the altitude of 5486 meters on the pass 

 of Gantong; at the summit, I felt absolutely no difficulty in breathing, 

 as long as I remained motionless, carried by my horse, but when I 

 tried to walk on an almost level road, fatigue and panting appeared 

 promptly. And yet I saw my servants, to reach the summit of the 

 pass, walk several hundred steps on very moderate slopes of snow, 

 without stopping to get their breath; only one was sick. (P. 288.) .... 



August 16, at the pass of Kioubrong (5581 meters), the same 

 immunity; I ascended there rapidly over a very gentle slope, and 

 walked quickly for more than an hour, without feeling any special 

 lassitude caused by the elevation, no pains of the head or ears, no 

 tendency to sleepiness, in a word, nothing particular, perhaps, but 

 a slight panting; and in fact, after a few minutes rest, my pulse rate 

 was 82. (P. 297.) 



The limit of perpetual snow in this region of the Himalayas 

 is hardly below 6000 meters, according to Jacquemont. 



Finally, Jacquemont wished to fix clearly the conditions of the 

 problem by a personal experience: 



I had ridden on horseback to Kioubrongghauti, and since the 

 experiment which I had made there of walking rapidly for an hour 

 in a place with an altitude of 5600 meters, after reaching it without 

 any fatigue, left me without doubt as to the cause of the strange 

 symptoms experienced by travellers who ascend to the summit of 

 Mont Blanc, I wished to climb the pass of Gantong on foot, to see 

 whether the walk, which was prolonged but prolonged moderately for 

 only five hours and very slowly, with numerous intervals of rest, on 

 slopes which are really very steep, but whose vertical height did not 

 exceed 1000 meters, would reduce me to the state of exhaustion descri- 

 bed by M. Gerard as the immediate consequence of the slightest 

 movement, as soon as one reaches the absolute elevation of 4572 

 meters. That was just the level of my starting point. 



Stimulated at the beginning of my walk by the morning chill, 

 sustained beside by the freshness of the wind, preoccupied by interest 

 in the objects which I saw at every step, often stopped by them, and 

 taking care after walking three hours to eat a light lunch to ward 

 off any feeling of hunger, which, I have found, always produces in 

 me in lofty places an extreme weakness and headaches, I arrived 

 without weariness, and almost without perceiving it, at the summit 

 of the pass of Gantong, at an elevation of 5576 meters. (P. 302.) 



But if Victor Jacquemont was almost free from any acute 

 symptom, and did not see any appearing in his travelling com- 



