various Altitudes, in connexion with the act of Ascending. 333 



noted was very high, considering that there could be at that 

 time no food in the stomach, and the ascent had been uninter- 

 rupted for the previous three hours. This was perhaps due to 

 a reaction, the temperature having fallen very low (34°'5) during 

 the ascent. 



Result II. — That the temperature of the body during the act 

 of ascending has invariably a tendency to fall, but that the degree 

 of cooling depends mainly on a condition of fasting, or want of 

 food, at the time. A rapid and steep ascent on an empty stomach, 

 when the body is out of breath and perspiring freely, appears to 

 be attended with the greatest reduction of heat. 



In twelve observations made while walking up hill the tempe- 

 rature of the body varied from 34°*5 to 36°- 5, the range being 

 thus 2°0. The greatest fall of temperature observed on four oc- 

 casions was as follows :— 



At 4000 metres .... 34*5, fasting. 



„ 2080 „ 34-5 and 35°, fasting. 



„ 3362 „ 34-5, fasting. 



About 2100 „ 35-0, fastin 



©■ 



The influence of walking up hill on the temperature of the 

 body was well marked in the two following experiments : — 



I walked up from Chamounix to Planpraz (Brevent) soon after 

 an excellent breakfast and during digestion. When halfway up 

 (at the "Chalet des Chablettes"), and after walking up hill for 

 an hour, my digestion was hardly over, and I was free from the 

 slightest sensation of fatigue ; my temperature under the tongue, 

 while ascending, was then much the same as before leaving 

 Chamounix, being first 36°"5, and a few minutes after 37°. I 

 then continued my way up to Planpraz, an hour's walk above 

 the previous station. Being in a hurry to attain this spot, I took 

 short cuts, climbing the face of the mountain, which was rather 

 steep, and I reached Planpraz much out of breath and perspiring 

 freely; the last few minutes before arriving, while walking, my 

 temperature was 34 0, 5, and shortly afterwards 35°, say 1° lower 

 than on reaching the " Chablettes." It was very obvious that 

 my morning meal was then no longer able to make up for the 

 loss of heat from the climbing which it had done an hour before ; 

 I had been moreover walking faster up a steeper hill than at 

 first. 



In the second experiment, in order to make sure that during 

 the act of climbing the process of cooling (to which the body 

 was subjected) was really due to muscular exercise and not 

 to a change of altitude, I took a mule at Courmayeur for a part 

 of the distance to the " Pavilion du Mont Frety," an altitude of 



