Summary and Discussion 341 



authors say, thanks to the inner tension of the fluids of the body 

 which counteract it; but if it diminishes, immediately this tension, 

 which nothing now checks, will urge the fluids to the periphery, 

 will fill the skin with blood, will swell it, will congest it, and by 

 rupturing the blood vessels will cause hemorrhages: it will be the 

 same as if the body were plunged into an immense cupping-glass. 

 Now this is what happens when one rises in the air: at an eleva- 

 tion of 3300 meters, 5000 kilograms will have been removed; at 

 5500 meters, half of the total weight, that is, 9000 kilograms. Why 

 should one be surprised at the serious disturbances which occur 

 then? 



This is the theory approved by the large majority of those who 

 have considered the question, particularly, 'we must say, travellers 

 and physicians. We find it suggested for the first time in a few 

 words by Bouguer (page 209) . Haller develops it at length (page 

 210) ; it is true that, recalling a strange idea of Cigna (page 206) , 

 he declared that there is a great difference between "air rarified 

 by the removal of a part of it and that which is lighter because 

 of the elevation. . . In the latter, although it has lost half its weight, 

 respiration takes place without difficulty." That is no stranger, 

 at any rate, than to see Bourrit maintain that at an equal elevation, 

 "the air of the Alps is rarer than that of the Cordilleras" page 

 213) . De Saussure accepted completely the theory of the "relaxing 

 of the vessels produced by the decrease of the compressing force 

 of the air" (page 215) . It was this illustrious physicist who ex- 

 pressed it most clearly. It was also accepted by Fodere (page 217), 

 Halle and Nysten (page 217), Gondret (page 220), Dr. Gerard 

 (page 222), Hipp. Cloquet (page 223), Burdach (page 225), Rey 

 (page 231), Brachet (page 235), Lombard (page 243), Heusinger 

 (page 245) , Foley (page 270) , Scoutetten (page 276) ; we mention 

 only the chief advocates. 



We see that this theory has the support of the most eminent 

 names. It is really painful to have to reject it by a sort of pre- 

 liminary question, as absolutely contrary to the laws of elementary 

 physics. But long before me, MM. Giraud-Teulon (page 246) and 

 Gavarret (page 279) had called upon the principle of the incom- 

 pressibility of liquids to combat this error. Valentin (page 244) had 

 even calculated that the removal of a half-atmosphere would 

 increase the volume of the body only about three hundred-thou- 

 sandths. It is quite evident that all pressures or decompressions 

 balance each other, immediately counteract each other, when they 

 are applied to the whole body, since it is composed entirely of 



