Decreased Pressure 951 



our theory, cannot refrain — though not without remorse — from sac- 

 rificing also to the ancient gods, the false gods: 



The acceleration of respiration and circulation really has as its 

 principal cause the more pressing need of oxygen .... But certain 

 secondary causes also favor this acceleration. Among others, we admit, 

 as a possible aid towards this result, the greater tension of liquids 

 and gases of the blood, an increase in tension which is generally con- 

 sidered to appear in lofty regions, and is due to the diminution of 

 surrounding pressure. It would give the blood greater fluidity, while 

 the diminution of atmospheric pressure would permit the capillaries 

 to dilate, they say, and consequently give the blood freer passage. 

 But has not the influence of the latter cause been somewhat exagger- 

 ated? Should not the intense cold of the regions where air is rarefied 

 amply counterbalance this effect, already doubtful, on the peripheral 

 circulation? The cold, in fact, produces a state of stasis of the blood 

 in the capillaries on which its influence can manifest itself, that is, 

 on those which lowering of pressure might influence. Now, this effect 

 of cold should lessen greatly the action (perhaps still problematical) 

 of atmospheric decompression in this case; and to support our opinion 

 we see in the observations that we have reported that this peripheral 

 circulation is far from being speeded up as much as is said. M. Glaisher 

 complains that his hands grew blue; in another ascent, he was forced 

 to pour brandy over the hands of his companion, Coxwell, which had 

 become black and numb, and we have seen the same thing take place 

 on other occasions. (P. 28.) 



These old hypotheses ought not to stop us now; a word or two 

 will be enough presently to summarize definite disproof. 



■ But we are far from treating with the same scorn the interesting 

 theory developed by M. Dufour. We have seen, in the historical 

 part of this book, that in 1874 this scientist, without yet knowing 

 of our experiments, had expressed the opinion that mountain sick- 

 ness is due to the exhaustion, through exaggerated muscular con- 

 tractions, of the ternary materials of the blood and the tissues, 

 materials necessary for the production of heat and work. The reply 

 to this theory appears of itself and we have expressed it in a few 

 words (page 340). The discussion which took place in the bosom 

 of the Medical Society of Switzerland having informed M. Dufour 

 of the results of my experiments, he somewhat modified his point 

 of view, and finally decided that one must distinguish between 

 "height sickness" and "fatigue sickness," the combination of these 

 two factors producing "mountain sickness." Here are his own 

 words: 5 



A. Height Sickness. The blood loses its oxygen supply according 

 to rules established by M. Bert for some animals. And so, if one can 

 • apply to man the results obtained in animals, at 4200 meters the blood 



