264 



Chapter XVII 



85 / and 93 % saturation, an important difference in the satu- 

 ration attainable. But probably the rise in the limiting percentage 

 saturation is less important than the effect on the rate at which 

 oxygen is taken up. Since this rate is directly proportional to the 

 pressure of the oxygen, the oxygen is taken up nearly half as fast 

 again in the lung of the acclimatised person. 



There are two points in the above argument which have been 

 passed over rather lightly because the argument itself only demanded 

 the mere mention of them. Yet they are both of considerable interest 

 on their own account. They are the following : firstly, why did I be- 

 come acclimatised at once on Monte Rosa when I did not change at 

 Teneriffe? and secondly, why did Douglas acclimatise at Teneriffe 

 when I did not do so? The fundamental principle is that the 

 acclimatisation is due to oxygen want. In order that you should 

 acclimatise satisfactorily you must do so gradually, and therefore 

 court oxygen want from the beginning of the ascent, then the acid 

 gradually finds its way into the blood and the CO., gradually finds its 

 way out. The most satisfactory way of doing this is to walk up the 

 mountain. The difference between my ascent of Monte Rosa and 

 that of the Peak was that the former was made on foot, the latter on 

 a mule. As regards the acidosis when I reached Col d'Olen there 

 was no doubt. Some of my blood was taken directly I arrived there ; 

 it was analysed by Mathison and contained the equivalent of 0*42 / 

 lactic acid. The following figures, obtained with Roberts' blood and 

 my own, illustrate this point. 



Equivalents of lactic acid in blood. 



At each effort of climbing then there was an acidosis which 

 only partially disappeared in the ordinary life of the place. An 

 interesting point was the fact which we discovered on coming down 

 to Col d'Olen from the Margherita hut, that the acidosis which 

 had been induced by going up there remained some time and 

 materially strengthened our position owing to the lowering of the 



