994 Summary and Conclusions 



If, in fact, the consumption of oxygen was the same in both 

 cases, the heat of the muscle should be less when there is work 

 produced; now, Heidenhain has shown that on the contrary it in- 

 creases, which demands a greater consumption of oxygen. We are 

 therefore justified in believing that the elevation of the weight of 

 the body in the act of ascent increases still more the amount of 

 oxygen taken from the venous blood by the muscles contracting and 

 consequently increases the distress of the organism. 



This explains the well-known fact that in lofty regions, while 

 walking on a level is easily endured, the ascent of the smallest 

 hills brings on serious disturbances. 



What we have just said of the mountain traveller, and what we 

 said before of the aeronaut, permits us to handle the question of 

 the chilling of the body during the act of ascent. The theory of 

 Lortet and Marcet states that, in conditions of decompression where 

 the temperature remains constant in a state of repose, it drops 

 when the ascent, which requires enormous mechanical labor, pro- 

 duces it at the expense of the heat developed by the organic oxida- 

 tions. I shall say first that in my opinion there is no transforma- 

 tion of heat into mechanical force in the organism; everything 

 seems to me to show that when forces of tension are set free under 

 the form of vital force in consequence of oxidative processes, heat, 

 electricity, and work are produced at the same time, in proportions 

 which vary of course, but whose variations are initial and do not 

 depend on subsequent transformations. We must then ask our- 

 selves whether it may be, not that heat is transformed into me- 

 chanical energy, but that the forces of tension, as they develop, 

 give out less heat in order to meet the requirements of mechanical 

 labor. When the question is put in this way, we must confess 

 that up to now the observations which bear out this theory can be 

 challenged, since the buccal thermometer cannot give accurate 

 results while walking is continued. M. Forel, in a recent work, and 

 M. Calberla, who took the rectal temperature, have always ob- 

 served an increase of temperature during the act of ascent. And 

 yet, I am persuaded that in higher regions, the statement of M. 

 Lortet would be verified. In our experiments we have seen mo- 

 tionless animals grow cold as a result of the diminution of pressure; 

 I am persuaded that if, at that moment, we had exacted of their 

 exhausted organism a production of mechanical work, their tem- 

 perature would have dropped still more, because, having already 

 passed the limit of equilibrium and having shown themselves 

 unable to oxidize their organism sufficiently to keep it in the ranks 



