114 Historical 



through the nose .... The instrument was always left in place for 

 at least fifteen minutes. (P. 31.) 



Fasting, while walking continues, the decrease of the tempera- 

 ture is, according to M. Lortet, almost proportional to the altitude 

 at which one is. This is shown by the following table. 



Lortet: Temperature 



So during the muscular efforts of the ascent, the temperature of 

 the body may drop four or five degrees, when one mounts from 1050 

 to 4810 meters. As soon as one stops for a few minutes, the tempera- 

 ture rises quickly to nearly its normal figure .... 



Since my return to Lyons, I have observed that when one ascends 

 rapidly one of the numerous stairways that lead to Fourvieres or the 

 Croix Rouge, there is regularly a drop in temperature which varies 

 almost always from three to seven tenths of a- degree. (P. 32.) 



It is to this drop in temperature of the body that M. Lortet 

 attributes all the symptoms of mountain sickness. In Chapter III 

 we shall give this theory and the objections it has aroused. 



The same day when MM. Lortet and Marcet suffered so severely 

 during the ascent, M. Ch. Durier 150 followed them, walking, so to 

 speak, in their footsteps. Strangely enough, neither he nor his 

 companions felt any symptoms: 



There were three of us, three companions of very different 

 temperament; one was a lad fifteen years old, the youngest traveller — 

 at least that I know of — ever to ascend Mont Blanc. Well! None of us 

 felt the slightest discomfort, not even breathlessness. (P. 66.) 



Why this difference in impression? M. Durier asks himself. 

 And to this question he gives an answer full of acuteness, of which 

 we shall make use later. 



