280 Chapter XVIII 



for instance, both had a value for K at 40 mm. CO 2 , which was about 

 '000212, mine was '000292. Neither of these suffered in the least 

 from mountain sickness ; I did, though it never actually amounted to 

 vomiting. In the case of Douglas' and my blood, these values for K 

 represented our actual curves. It appeared that Douglas' more 

 gradual dissociation curve meant a more gradual degree of adapta- 

 tion. I did not begin to adapt till my alveolar oxygen pressure was 

 10 mm. below that of Douglas, mine being about 50 mm. of oxygen 

 and his being 60 mm. 



At that pressure the percentage saturation in each of our bloods 

 was roughly the same, but I was in a very much worse position than 

 Douglas 



(1) Because a trifling further drop in the oxygen pressure in the 

 blood meant a large drop in percentage saturation in my case and a 

 small one in Douglas' case. 



(2) Because 60 mm. oxygen as compared to 50 meant that, other 

 things being equal, oxygen could be taken up more rapidly in the 

 ratio of 6/5. 



(3) Such a trifling drop in the oxygen pressure to which the 

 actual blood was exposed might be due simply to an increase in the 

 pressure gradient between the outside and the inside of the lung 

 epithelium. An increase of this sort would be the direct result of 

 a little exercise. 



Zuntz' case was a little different from that of Douglas. It is true 

 that with the same CO 2 pressure their bloods gave the same dissocia- 

 tion curves, but in point of fact Zuntz had a less alveolar C0 2 pressure 

 and his dissociation curve at this pressure was more like mine than it 

 was like Douglas'. But the lower CO 2 pressure gave him the advantage 

 over me, for it meant of course a higher oxygen pressure. 



Between the dates of the Teneriffe and Monte Rosa expeditions 

 two mountaineers of eminence were kind enough to give me blood 

 for analysis, these were Oscar Eckenstein, who claims to have lived 

 at an altitude of 20,000 feet longer than any other man, and 

 Longstaffe, the Himalayan explorer. The fact that the blood of these 

 two persons, when exposed to the standard C0 2 pressure, gave the 

 lower values for K than any other human blood that I have analysed, 

 was an interesting confirmation of my theory. 



It became a matter of some little interest to me at Pisa to specu- 

 late as to which of the members of the Monte Rosa party would 

 stand the high altitude best. The five persons fell into three groups. 



