244 Historical 



There is a very important element in mountain climates; it is a 

 lessened atmospheric pressure and consequently an air which is less 

 dense, as well as a decrease in the quantity of oxygen which is 

 necessary to maintain life by means of respiration. To these last two 

 circumstances are due in great part the phenomena observed on lofty 

 mountains, and to these two I wish to call the attention of my readers 

 for a few moments. 



If we question physics, we shall see that the total weight of the 

 atmosphere represents as many times one hundred three kilograms 

 as there are square decimeters on the surface of our body, so that, 

 depending upon the height of different persons, the total weight sus- 

 tained by our organs will vary between fifteen and twenty thousand 

 kilograms. If then we leave a country more or less near sea level for 

 a higher elevation, our bodies will sustain a pressure which will 

 diminish in proportion to the increase in altitude. We can understand 

 what a shock it must be to our organs when the enormous weight 

 to which they are usually subjected is diminished by a sixth, a quar- 

 ter, and even a third, as is noted on the Righi, the Saint Bernard, or 

 the summit of Mont Blanc. And if we add to this decrease in pressure 

 the no less important change which takes place in the density of the 

 air, and consequently in the quantity of oxygen, we shall not find it 

 difficult to explain the various disturbances which occur in the respi- 

 ration, the circulation, the locomotion, and the digestive processes 

 of those who climb the lofty peaks of our Alps, or dwell there for a 

 time. 



In the appearance of the symptoms of which we are speaking, 

 what part is played by a low pressure, and what part by an insufficient 

 quantity of oxygen? That question is hard to answer, since both 

 respiration and circulation should be equally modified under these 

 two influences and should react on the muscular strength; on the 

 other hand, now that recent researches have shown that the head of 

 the femur is kept in the cotyloid cavity by means of the atmospheric 

 pressure, it is clear that a decrease in the weight of the air should 

 make movements more difficult; so that we reach the conclusion that 

 the phenomena produced in living bodies, transported to great heights, 

 are the result of the two meteorological conditions of which we have 

 just spoken: a decreased pressure and a smaller quantity of oxygen. 

 (P. 273.) 



But shortly after this, M. Giraud-Teulon, a French physician 

 who was very competent in matters relating to physics, completely 

 exposed the fundamental error upon which M. Lombard, along 

 with so many others, was relying. 



Long before this, Valentin, 71 ' calculating the amount of the 

 changes in the weight of the atmosphere on the surface of the 

 human body at different heights above sea level, and admitting 

 that organic matters are compressible to the same degree as water, 

 had shown that: 



