232 SUSCEPTIBILITY TO MOUNTAIN SICKNESS 



in the liver it diminishes. Nucleated red cells may appear in the 

 blood. Muntz kept rabbits on the summit of the Pic du Midi, 

 at 2877 m., for seven years. Others he kept in the plain. On 

 comparing the blood he found : 



The increase in the amount of haemoglobin is obviously a 

 reaction on the part of the organism, which strives to compensate 

 for the low 2 pressure. 



It is interesting to note that diving birds which stay a 

 minute or two under water have double as much blood as 

 ordinary birds (Bohr). 



SUSCEPTIBILITY TO MOUNTAIN SICKNESS 



From the previous pages it should have become evident that 

 the susceptibility of certain individuals to mountain sickness, and 

 the immunity of others, depends on the depth of the pulmonary 

 ventilation and vigour of the circulation, and on the absorptive 

 power of the blood, which may vary with both the quality and 

 quantity of the haemoglobin. All these factors may be modified 

 by training. To climb to great altitudes in an untrained con- 

 dition is to court disaster. 



THE THERAPEUTIC VALUE OF MOUNTAIN Am 



The beneficial action of mountain climate lies in its purity 

 from dust and bacteria, in the bracing cold and intense insolation, 

 in the strengthening of heart and respiratory mechanism, in the 

 increased respiratory metabolism, and increased formation of 

 haemoglobin. It is not by any means proved that the two last 

 factors are due to high altitudes. Probably sea or country air 

 with exhilarating surroundings will induce the same changes in 

 town-dwellers. 



