Decreased Pressure 1005 



low levels, is harmful, and tonics, on the contrary, are really 

 beneficial. 



First among these tonics we should place respiration of an air 

 slightly superoxygenated or an air compressed so as to restore 

 normal tension. I am convinced that establishments like those of 

 Junod, or Pravaz, or Tabarie would render great services at Mexico, 

 La Paz, Cuzco, and Cerro de Pasco, especially to new-comers and 

 invalids. 



But I shall stop now without drawing any conclusion. It has 

 been enough to show in what physiological conditions the dwellers 

 in high places must be, and how they can accustom themselves to 

 these serious disturbances. As to the reality and the soundness of 

 this acclimatization in individuals, from generation to generation, 

 and the apparent immunity of certain human races or animal 

 species, these are questions whose importance I understand fully, 

 but which devolve upon the hygienist or the naturalist, and whose 

 solution, besides, cannot be found in laboratory experiments. It is 

 upon experimental ground, which is familiar to me and on which 

 I am sure of my steps, that I shall obstinately remain. 



4. Animal and Plant Life at High Elevations. 



The native or imported animals which inhabit the lofty regions 

 of the Cordilleras and the Himalayas present the same problem as 

 the human beings of whom we have just spoken. With both men 

 and animals, the native born, species or races, have infinitely more 

 resistance than those who came to compete with them. The Indian 

 yaks, the American llamas can serve as beasts of burden without 

 suffering where mules and horses often die from the decompression. 



Birds can rise still higher than mammals, the condor particu- 

 larly, which mounts in flight to 7000 meters, and soars for hours at 

 the heights at which the motionless aeronaut begins to feel serious 

 discomforts, and which the brothers Schlagintweit reached on the 

 mountain sides only at the cost of keen suffering due to the rarefied 

 air. Now in my decompression bells, birds showed themselves more 

 susceptible than mammals, and the birds of prey on which we 

 experimented were sick almost as soon as the sparrows. How can 

 we account for this double contradiction in incontestable data? 



We have seen that the proposed explanations could not satisfy 

 us, and I confess that I have no other to propose. To attempt one I 

 should first need to master experimental data which are absolutely 

 unknown to me. First, I should have to try in closed vessels the 

 effects of decompression on condors, not menagerie birds, perhaps 



