302 M. Humboldt on txco AtteinJ)ts to ascend Chimborazo, 



of the Stomach," as painful symptoms of the mountam-skkticss, 

 which in these respects is analogous to sea-sickness. On the 

 volcano of Pichincha I once felt, without experiencing haemor- 

 rhage, so violent^an affection of the stomach, accompanied by 

 giddiness, that I was found senseless on the ground, just as I 

 left my companions on a wall of rock above the defile of Verde- 

 Cucha, in order to perform some electrical experiments on a per- 

 fectly open space. The height was inconsiderable, below 13,800 

 feet. But on the Antisana, at the considerable elevation of 

 17,220 feet, our young travelling companion, Don Carlos Mon- 

 tufar, bled freely from the lips. All of these phenomena vary 

 according to age, constitution, the tenderness of the skin, the 

 preceding exertions of the muscular powers ; yet for single indivi- 

 duals they are a kind of measure of the atmospheric tenuity, and 

 of the absolute elevation reached. According to my observations 

 in the Cordilleras, these symptoms manifest themselves in white 

 people, with a mercurial column between 14 inches, — and 15 

 inches 10 lines. It is known that the estimates regarding 

 heio-hts, which aeronauts maintain that they have reached, gene- 

 rally deserve but little credit, and if a more certain and extremely 

 accurate observer, M. Gay Lussac, who, on the I6lh of Sep- 

 tember 1804-, reached the vast height of 21,600 feet (thus between 

 the heioht of Chimborazo and Illimani), experienced no haemor- 

 rha^e, this is perhaps to be ascribed to the absence of muscular 

 exertion. According to the present condition of eudiometry, 

 the air of those lofty regions appear to contain in proportion as 

 much oxygen as that of lower heights ; but since in that attenu- 

 ated air— .the barometric pressure only one-half of that to which 

 we are o-enerally exposed — the blood in each act of respiration 

 takes up a smaller quantity of oxygen, it is certainly conceivable 

 that a general feeling of weakness should take place. Why this 

 asthenic as in fainting, should excite nausea and a tendency 

 to vomiting, it is not our purpose to determine ; as little is it 

 here to be proved, that the oozing of blood (the haemorrhage 

 from the lips, gums, and eyes), which also has not been expe- 

 rienced by all, at such great heights, — can by no means be sa- 

 tisfactorily explained by the absence of a " mechanical counter- 

 pressure'" on the vascular system ; our attention should rather 

 v,e engaged in examining the probability of the influence of a 



