Summary and Discussion 347 



that there must be an excess of gas stored up, and consequently 

 distress, just as much in ascending from Chamounix (1050 meters) 

 to the Pierre-Pointue (2040 meters) as in ascending from the 

 Grand-Plateau (3930 meters) to the summit of Mont Blanc (4810 

 meters) ; yet that has never been observed. Furthermore, even 

 at sea level, a iask which is sufficiently energetic and prolonged 

 should bring on the same result, and that is not the case. The 

 necessary element, altitude, is not considered at all in this ex- 

 planation. 



As to the fact advanced, it in itself is far from proved. There 

 is no proof that the carbonic acid, the formation of which is in- 

 creased during the labor of ascent, can really be stored up in the 

 blood. According to M. Gavarret himself, when a man lifts him- 

 self vertically 2000 meters, he forms 65 liters of carbonic acid, 

 above the 22 liters which he produced per hour in his normal re- 

 quirements. It will take him at least six hours to cover these 2000 

 meters. (MM. Lortet and Marcet took 8 hours to go from Cha- 

 mounix (1050 meters) to the Grands-Mulets (3050 meters). We 

 must then add 65 liters to the 132 liters formed during this time; 

 in other words, the quantity of carbonic acid produced will have 

 been increased by one third. Now it is very probable that the pul- 

 monary excretion will have been sufficient to expel this small 

 gaseous excess; the arterial blood, the nutritive blood, the impair- 

 ing of which is so dangerous, is therefore probably not overladen 

 with toxic gas. On the other hand, we know, from the experi- 

 ments of M. CI. Bernard, that one can safely inject into the ve- 

 nous system of an animal enormous quantities of carbonic acid, 

 without producing symptoms, because of the rapidity and the en- 

 ergy of the pulmonary exhalation. And so nothing proves that 

 there is an excess of carbonic acid in the arterial blood; nothing 

 proves that this excess, if it exists, is capable in its actual propor- 

 tions of causing symptoms; at any rate, these symptoms should 

 appear at any altitude whatsover, and consequently have no con- 

 nection with mountain sickness. 



Theory of de Saussure and Martins. De Saussure noted, as we 

 have reported (page 216), that, on the summit of Mont Blanc, 

 "since the air had hardly more than half of its usual density, com- 

 pensation had to be made for the lack of density by the frequency 

 of inspirations. . . . That," he said later, "is the cause of the fatigue 

 which one experiences at these great heights. For, while the 

 respiration is accelerating, so also is the circulation." The former 

 view, however, was incomplete, or, rather, incompletely expressed. 



