Theories and Experiments 293 



The editor of the Bulletin summarizes the discussions which 

 arose about the etiology of mountain sickness among the members 

 of the Swiss Alpine Club in this odd sentence: 



The principal factors are need of food, the intensity and rapidity 

 of the work, and the mental characteristics. We cannot remove com- 

 pletely from the list of causes the rarefaction of the air and intoxica- 

 tion by carbonic acid. The question, which has a certain interest, 

 therefore still offers some unknown quantities to be found. (P. 140.) 



Moreover, the following passage, taken from the celebrated 

 physicist and daring mountain climber Tyndall, also gives inter- 

 esting information on this subject: 



It is not a good idea to begin these ascents without having eaten 

 and it is not good to eat heartily. One must eat a little here and 

 there, as the need appears. But left to itself, the stomach inevitably 

 falls ill, and the energy of the system is rapidly exhausted. If the 

 illness brings on distaste for food, vomiting may ensue and the stomach 

 be conquered. A little food is enough to restore it. The strongest 

 guides and the sturdiest porters are sometimes reduced to this ex- 

 tremity. "Sie mussen sich zwingen". The guides attribute these ca- 

 prices of the stomach to the great elevation of the air. Perhaps that 

 is one of the causes, but I am inclined to think that something is 

 likewise due to movement,— the continuous action of the muscles on 

 the diaphragm. The conditions under which the journey is made and 

 those which have preceded it also deserve much attention. One sleeps 

 little or not at all; the morning meal is taken at an unusual hour; 

 and if the start is to be made from a cave or a hut instead of a hotel 

 bed, there is a serious aggravation of bad conditions. It cannot be the 

 slight difference in height between Mont Blanc and Monte Rosa that 

 makes the effects of their ascents so different. It is because, for the 

 first, one makes his coffee of the melted snow of the Grands-Mulets, 

 and has a bare plank for his bed; whereas for the other, he enjoys 

 the inn of the Riffel, very comfortable in comparison. Milk and a 

 crust of bread are all I need to sustain my strength and ward off 

 mountain sickness. (P. 304.) 



These very wise remarks have been made by many travellers. 

 The degree of fatigue preceding the ascent is an element the im- 

 portance of which is well known today. The same thing is true 

 of the habit of walking and of living in the mountains. The fol- 

 lowing observations of M. Durier 132 in this regard deserve our 

 approval. We have told earlier how, by a strange coincidence, 

 M. Durier and his companions, who suffered no ill effects from the 

 decompression, ascended Mont Blanc just behind MM. Lortet and 

 Marcet, whose symptoms we have given. M. Durier explains this 

 difference in the following words: 



In general, the physiologists who have studied the effects of moun- 

 tain sickness upon themselves tear themselves from work in their labo- 



