996 Summary and Conclusions 



greater resistance to the sickness presented by travellers after a 

 few preliminary ascents: the expenditure of strength is thus re- 

 duced to its minimum. 



For all these questions, for the influence of fatigue, of cold, etc., 

 we refer to the summary already presented of data that have long 

 been known (pp. 315-328). Now that we know that everything is 

 explained by the diminution of the oxygen of the blood, we under- 

 stand how a useless excess of muscular contractions can more 

 rapidly bring the anoxemia to its asphyxiating degree, and cause 

 the sickness. 



As to bad or insufficient nutrition, it is clear that if the oxidable 

 materials are not furnished in suitable quantity, the difficulties of 

 the organism, in the expanded air, in maintaining the necessary 

 combustions, will be increased by so much. But there is nothing 

 there, except the intensity, which is peculiar to lofty places; the 

 expenditure upon which M. Dufour has justly insisted will take 

 place to the same degree in every ascent, whether it is below 1000 

 meters or above 4000, and yet the subsequent phenomena will be 

 very different. 



As to a more precise analysis of the causes and the value of 

 acclimatization, it seems to me that it will be better placed in the 

 following section, when I speak of the dwellers in high places. 



Prophylaxis. To take precautions against the cold, to eat suit- 

 ably, to reduce muscular efforts to their minimum, to train oneself 

 by preliminary ascents and by a prolonged stay in lofty regions, to 

 spend the night before the main ascent as high as possible, not to 

 hurry on steep slopes, to break the ascent by frequent halts, to eat 

 little and often, such are the general precautions suggested by all 

 we have said. 



The use of oxygen, that sovereign protector against the dangers 

 of rarefied air, here presents much greater difficulties than for 

 balloon ascensions. It is impossible, of course, to carry bags of 

 oxygen containing several cubic meters up a mountain. Only two 

 means present themselves: to enclose in solid receivers the neces- 

 sary provision of oxygen, compressed to several atmospheres; or to 

 prepare the necessary oxygen extemporaneously on the spot, from 

 time to time. 



To study the possibility of the first means, I applied to M. 

 Denayrouze, who put at my disposal an apparatus composed of two 

 cylinders of sheet steel one millimeter thick, capable of enduring a 

 pressure of 40 atmospheres, which one could carry on his back like 

 a tourist's pack: the two cylinders combined being only 36 cm. high 



