436 



SCIENCE 



[N. S. Vol. XLIX. No. 1271 



continued would resiHt in mountain sick- 

 ness. The latter effect especially is one 

 which was the suhject of careful study by 

 an expedition of which I was a member, 

 and which during the summer of 1911 

 spent five weeks at the summit of Pike's 

 Peak, Colorado, altitude, 14,100 feet. Bar. 

 450 mm. "We were there enaibled to make 

 observations upon hundreds of tourists 

 who ascended the Peak, and who were ac- 

 climatized at most to the altitude of Colo- 

 rado Springs or Manitou at the .foot of 

 the mountain. "We saw a number of cases 

 of coUapse — fainting — fi'om oxygen defi- 

 ciency as shown by the striking cyanosis. 



In the majority of cases, however, tour- 

 ists Who spent no more than the regulation 

 half hour at the sumimit of the Peak, and 

 then descended, experienced no acute ill 

 effects. Headache and some degree of 

 nausea were common even among these 

 persons, however — often developing slowly 

 for some hours after their descent. On the 

 other hand, among persons who remained 

 over night, and were thus exposed for 

 several hours to deficiency of oxygen, the 

 classic symptoms of mountain sickness oc- 

 curred ; and few escaped. Their second day 

 at the summit was marked usually by ex- 

 treme discomfort — ^headache, nausea, vom- 

 iting, dizziness and extraordinary instabil- 

 ity of temper — symptoms which were strik- 

 ingly exacerbated by even the smallest use 

 of alcohol. 



Our immediate party passed tlirough 

 these conditions and after two or three 

 days, or in one case nearly a week, re-at- 

 tained practically normal health. A defi- 

 nite functional readjustment had occurred. 

 To illustrate and emphasize the nature of 

 this readjustment I will quote a recent ex- 

 periment'' of my friend the leader of the 

 Pike's Peak expedition. Dr. J. S. Haldaue. 



He has equipped his laboratory at Ox- 



s Personal commiuiieation. 



ford with a small lead-lined chamber in 

 which a man can be hermetically closed. 

 The carbonic acid which he exhales is con- 

 tinually absorbed by alkali, so that no ac- 

 cumulation occurs, while the oxygen is 

 progressively decreased by the breathing 

 of the man himself. Dr. Haldane found 

 that after a day or two in this chamber he 

 had reduced the oxygen to an extent com- 

 parable to Pike's Peak. At the same time 

 there had evidently occurred in himself a 

 gradual process of adjustment, for he felt 

 quite well. At this stage he invited an- 

 other person to come into the chamiber with 

 him, and he had the satisfaction of ob- 

 serving the immediate development of blue- 

 ness and the other symptoms of oxygen 

 collapse in his companion. 



Evidently acclimatization is a very real 

 phenomenon and of the utmost importance 

 to any one exposed to a lowered tension of 



As we observed it in ourselves during our 

 stay on Pike 's Peak acclimatization consists 

 in three chief alterations: (1) increased 

 number of red corpuscles in the blood; (2) 

 some change in the lungs or blood (Hal- 

 dane considers it the secretion of oxygen 

 inward by the pulmonary tissue) which aids 

 the absorption of oxygen, and (3) a low- 

 ering of the C0„ in the alveolar air of the 

 lungs. This lowering of the CO, in the 

 lungs is bound up -with increased volume of 

 breathing. It is the concomitant of a de- 

 creased alkaline reserve in the blood just as 

 in nephritis and diabetes. Acclimatization 

 in this respect consists therefore in the de- 

 velopment of a condition which would now- 

 adays be called acidosis. 



All of these changes are of a quantitative 

 character. Miss FitzGerald'' has supple- 

 mented the results obtained on Pike's Peak 

 by an extensive series of careful observa- 



eFitzGeraia, M. P., Phil. Trans., 1913, B. 203, 

 p. 351, and Proc. Boyal Soc, 1914, B. 88, 248. 



