Theories and Experiments 237 



During exertion, there is a stasis of blood in the capillaries and 

 congestion in the brain, the lungs, and the muscles. When one makes 

 a series of almost uninterrupted efforts, .... when one runs up a 

 stairway, .... vision is dimmed, vertigo occurs, a painful fatigue is 

 felt in the limbs, and muscular strength fails. But if one stops to get 

 his breath before the effects of the cerebral and pulmonary congestion 

 have reached this point, the blood then flows back towards the heart, 

 the face grows pale, and a well denned sensation of fainting is felt; 

 sometimes the syncope occurs even when one has not taken care to 

 place himself immediately in a horizontal position .... 



If now we consider the phenomena observed in the organism at 

 great heights, we find exactly the same course and the same signs. 

 Except that the rarefaction of the air, by making respiration more 

 frequent and the panting more rapid, necessarily hastens the rest of 

 the ordinary effects of exertion .... 



The slight hemorrhages of the gums, the imminence of hemoptysis, 

 and the epistaxis are explained by the congestion, as a result of 

 exertion .... 



As to the distress in the stomach, must we not consider the grad- 

 ual expansion of the intestinal gases under a constantly decreasing 

 pressure of the atmosphere as contributing greatly to this phenomenon 

 and to those which accompany it? ... . And yet we have not observed 

 any increase in the volume of the abdomen. (P. 65-68.) 



We see that M. Lepileur considers that everything is explained 

 by congestions of the muscles and the nervous centers, due to 

 exertion and increased by the panting, about the cause of which 

 he says absolutely nothing. 



It appeared very difficult, after so complete and detailed an 

 observation, to deny the harmful effect of altitude under certain 

 circumstances. And so, following the account of his ascent of the 

 Wetterhorn (3707 meters), on August 31, 1845, A. Vogt 70 protests 

 against denials which are at least unwise; moreover, he tries to 

 explain them, but he is not very successful in this attempt: 



We see (he says) in the narratives of travellers who have climbed 

 lofty mountains strange contradictions; some mention frequent and 

 more or less serious disturbances, others deny them completely. It 

 seems to me that three factors act upon the human organism at great 

 altitudes: 



1) The decrease of weight of the atmosphere and the consequent 

 expansion of the air; 2) the dryness of the air; and 3) the light 

 reflected from the stretches of snow. 



Martins, Barry, Agassiz, Desor, Escher von der Linth, etc., who 

 felt no symptoms, blame the imagination of their predecessors. I can 

 contradict them on one point. During the night which we passed at 

 the Aaresattel, I was astonished at the rapidity of my breathing; my 

 respiratory rate was twice as great as on the plain, although I did not 

 feel the slightest discomfort. 



