Chapter IV 

 SUMMARY AND CRITICISMS 



The time has come to summarize the long series of observa- 

 tions, experiments, and theories, the details of which we have 

 just related. After placing before the eyes of the reader nearly 

 all that has been written about the effect of decreased atmospheric 

 pressure, by the laborious but certain method of word for word 

 quotations, we should now simplify his task by condensing all 

 these varied assertions, often redundant and sometimes contradic- 

 tory. 



We must, moreover, subject to careful examination the expla- 

 nations suggested, opposed, or eclectically collected by travellers, 

 physicians, physiologists, and physicists, who have considered in 

 its various aspects this question, which is apparently so complex, 

 but really so simple, as we shall show. In this part of my task I 

 shall, of course, set aside the arguments drawn from my own 

 experiments. It is by ideas previously known that I hope to prove 

 that at the time when I began my researches, there existed in 

 science no theory — I do not say demonstrated, for that is evident — 

 which could sustain thorough criticism. Even the truth, when it 

 was found, was mingled with so many errors or was so unfurn- 

 ished with proofs that it could not force its clear evidence upon 

 rebellious minds. Now anyone is right only when he can prove 

 to everyone that he is right: "To keep on answering," Voltaire 

 said, "is to prove that no answer has been given." 



The present chapter is naturally divided into three parts: the 

 conditions under which mountain sickness appears, the summary 

 of the symptoms which constitute it, the careful examination of 

 the theories suggested to explain it. 



1. Conditions Under Which Mountain Sickness Appears. 



The most general fact emerging from our study is that when 



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