310 Historical 



any discomfort except that resulting from a somewhat accelerated 

 respiration, and a little more heaviness in the limbs .... 



From these experiments M. Virlet d'Aoust has drawn the conclu- 

 sion that the so-called mountain sickness is merely great fatigue re- 

 sulting principally from heaviness due to the decrease of the layer of 

 air which surrounds the traveller and which supports him in the lower 

 regions .... 



M. d'Abbadie asked the author whether a distress manifested by 

 dizziness and vomiting did not appear on lofty peaks. M. Virlet d'Aoust 

 stated that he felt nothing of the sort nor did his travelling com- 

 panions. M. de Puydt said that he had crossed the highest peaks of 

 the Andes, from the equator to the sixth degree, north latitude; that 

 he had reached altitudes of 4800 meters and that he had never felt 

 any of these fatigues; and yet he had travelled more than 450 leagues 

 in the Andes. M. l'abbe Durand supported this opinion, recalling the 

 official ascent of the great volcanoes ordered by the government of 

 Ecuador. Finally, M. Maunoir said that the effect of ascents, even in 

 the mountains, must vary with the health conditions and the constitu- 

 tion of the traveller. (P. 401.) 



M. Virlet d'Aoust 130 returned to this subject in the session of 

 July 7; he still followed the same strange method: 



M. Virlet dAoust, resuming the subject studied in a former 

 session, that is, the effect of the rarefaction of the air in the higher 

 regions of the atmosphere, reported an ascent of the volcano of 

 Arequipa or Misti, the altitude of which is 5650 meters, during which 

 the travellers were not at all inconvenienced (Reference to the Bulle- 

 tin). (P. 107.) 



The Explorateur of July 15, 1875, is much more explicit: 1,1 



Mountain sickness. In support of what he had previously said, on 

 the occasion of his ascents of Popocatepetl and Ixtaccihuatl, in refer- 

 ence to the so-called mountain sickness, M. Virlet d'Aoust reported 

 another ascent, that of the volcano Misti, more often designated by 

 the name of the volcano of Arequipa, in Peru, which led to the same 

 conclusions. Dr. J. T. Coates, of the United States, who made the 

 ascent, left Arequipa September 22, and camped for the night at the 

 foot of the mountain, situated 30 miles northeast of this city. The 

 next day very early, accompanied by three guides and furnished with 

 two aneroid barometers, he undertook the ascent. The little caravan 

 could travel on horseback at first; but after an hour, since the grade 

 became too steep and the difficulties kept increasing as they advanced, 

 they had to continue on foot. 



After ten hours of difficult walking, at half-past six in the even- 

 ing,, they finally reached the summit of the volcano, without having 

 experienced hemorrhages, or difficulties in breathing, or nausea, or 

 headaches, or any other of those painful sensations which, it is 

 claimed, should be felt by persons who venture in the mountains to 

 altitudes of more than 3000 meters .... 



Finally, M. Virlet d'Aoust thought he should mention another still 



