Theories and Experiments 245 



For one atmosphere of added pressure, the decrease of volume 

 would be about 0.2 of a cubic inch, that is, 1/22522 of the total volume 

 of the body. 



We see then that the volume of a man who was on the summit 

 of Mont Blanc and let himself slide down would contract only seven 

 one-hundred-thousandths. (Vol. I, p. 84.) 



However, this clear demonstration of the lack of importance of 

 changes in pressure considered from the mechanical point of view 

 had not kept a very eminent author, Heusinger, 80 from repeating 

 with many details the explanation carelessly approved by so many 

 travellers: 



The pressure of the atmosphere upon the body diminishes .... At 

 sea level, it has been calculated that an adult man would sustain a 

 pressure equal to 33,893 pounds; if he ascends to the height of Mont 

 Blanc, the pressure will be only 19,334 pounds .... The bones will 

 no longer be held in their articulations with the same strength, the 

 muscles will have to exert greater force, fatigue therefore will be 

 greater, .... the blood will be held with less force in the vessels, it 

 will have a tendency to transude and to form hemorrhages where 

 the walls are thin enough, and the blood will accumulate in the less 

 contractible organs, where the capillary vessels can be expanded more 

 easily, for example, in the mucous membrances, the lungs, and the 

 brain; there will be congestion in these organs; the heart, which has 

 fewer obstacles to overcome, will contract more often and the pulse 

 will become more frequent. (Vol. I, p. 252.) 



We must note that to this erroneous cause a number of others 

 are added, which are more or less justified, according to the 

 vagaries of the eclectic method. First come evaporation due to 

 decreased pressure and dryness, lower temperature, the action of 

 the rays of the sun, which is stronger and "penetrates the body 

 more deeply, and irritates the eyes, the brain, and the spinal cord", 

 then electricity, "probably stronger and less often negative", and 

 finally the lessened quantity of oxygen in the rarefied air, which 

 "counterbalances the frequency of the respiration and the circu- 

 lation". 



To return to the mechanical explanation, it was absolutely 

 demolished by the work of M. Giraud-Teulon, and we are surprised 

 that after such a thorough refutation, it has appeared again in 

 books and even in the academies. 



M. Giraud-Teulon S1 first lays down two principles which have 

 been too much forgotten by physicians and physiologists, before 

 and after him: 



