330 Historical 



composed our little caravan rose by 4 to 8; it was counted, of 

 course, after a long rest. Lieutenant Wood only by chance noticed 

 the extraordinary rapidity of his pulse, so that he thought he was 

 feverish (page 143) . 



When the difference in level is very great, the acceleration 

 becomes considerable. Moreover it is, as de Saussure said (page 

 85) , in proportion to the intensity of the distress experienced. The 

 extraordinary rates of 130 and 140 are not very rare on lofty moun- 

 tains: "My heart", says Mistress Hervey, "was going a railroad 

 pace" (page 149) . Parrot tried to establish a sort of ratio, which 

 might have served as a measure of the height, between his pulse 

 rate and the altitude reached (page 122). The table published by 

 Lortet (page 114) is very interesting in this regard; but such a 

 regularity is far from being general. At great heights, the acceler- 

 ation of the pulse becomes unendurable; it is accompanied by 

 buzzing in the ears, throbbing in the carotids and temples, and 

 more or less violent palpitations which become terrifying. This 

 acceleration does not seem to be controlled by the use of digi- 

 talis (page 151). 



This modification is not transitory; it continues through the 

 whole sojourn in lofty places. It is regrettable that exact obser- 

 vations on this point are extremely rare. So I think I should quote 

 here those which were recently published by M. Mermod. 



M. Mermod" counted his own pulse rate repeatedly at the 

 three stopping places of Erlangen (323 meters), Lausanne (614 

 meters), and Sainte-Croix (1090 meters); the sojourn in each ot 

 these places lasted several months. These observations were made 

 with meticulous care, and all necessary precautions were taken so 

 that the causes of error might be less than the variations, evi- 

 dently very slight, which the circulation might show under equally 

 slight differences in altitude. The average of 900 observations 

 made at Erlangen was 62.76 heart beats, that of 577 observations 

 made at Lausanne was 66.68, and that of 333 observations at Sainte- 

 Croix 68.87. The increase of the number with the altitude was 

 noted at all hours of the day. 



M. Jaccoud (see page 297) also observed on the Engadine a per- 

 sistent acceleration of his own pulse rate. 



I should, however, mention on the opposite side the observ- 

 ations of Dr. Armieux (page 299) , who found an average decrease 

 of 3.85 heart beats from Toulouse (200 meters) at Bareges (1270 

 meters) . 



The frequency does not show the only modification in the pulse. 

 Its strength is greatly diminished, it becomes irregular, very 



