86 Historical 



who were ill, I am sure that my pulse rate would have dropped 

 several beats. (Vol. Ill, p. 85.) 



The following year, he went with his son to stay on the col du 

 Geant (3360 meters) from July 3 to July 19, 1788; this trip, which 

 filled the guides with terror, was undertaken with the purpose of 

 attempting experiments which, on Mont Blanc, "the shortness of 

 the time and the discomfort caused by the rarity of the air pre- 

 vented me from carrying out." (Vol. IV, p. 217.) One whole 

 very interesting chapter is devoted to Observations Relating to 

 Physiology: 



§2105. It was interesting to note what effect upon our bodies 

 would be caused by a prolonged stay in an air as rarified as that 

 which we were breathing on the Col du Geant. It must be recalled 

 that the average height of the barometer was, during our stay, about 

 19 inches, that is, 9 inches lower than at sea level, and that therefore 

 the density of the air there was nearly one third less. 



M. Odier, a doctor in medicine, very eager for the progress of his 

 profession, had given me some questions which were to serve as text 

 for my observations. 



§2106. To determine precisely the degree of animal heat. During 

 the morning of July 17, at a moment when I was very calm, and 

 without having made any violent movement, I placed under my 

 tongue a small mercury thermometer keeping my mouth closed, and 

 at the same time I observed this thermometer with a magnifying 

 glass. It was at 29 Vz, and registered the same degree under the same 

 circumstances on the plain. 



To count the number of inspirations and expirations which a man 

 in repose and not forewarned makes in a minute, and also the rela- 

 tion of this number to that of the pulse rate. Under the same circum- 

 stances as those of the preceding paragraph, at first I found 75 heart 

 beats for each inspiration and as many for each expiration. But 

 another time, taking a larger number, which for that very reason 

 deserves greater confidence, I found that I made 10 inspirations and 

 expirations in 35 seconds, which amounts to 17 per minute, and that 

 my pulse rate was also 79 per minute. 



§2107. To try to inspire deeply enough to stop the pulse in the 

 left wrist, supposing that the same individual can do so on the plain. 



July 19, when I arose, seated on my pallet, I succeeded in stop- 

 ping the pulse of the left wrist, prolonging the inspiration for ten 

 seconds; immediately I repeated the test, and the pulse stopped at 

 the fifteenth second; the third time, at the thirty-fifth second the 

 pulse was still resisting when I was forced to catch my breath. When 

 I made the same test standing, I could not stop my pulse; but it is 

 true that I could prolong the inspiration only for 32 seconds. Therefore 

 this test appears, at least for me, not susceptible of regular com- 

 parison. 



§2108. To count the pulse in a perfectly vertical position; if the 



