248 



Further Observations on the Changes in the Breathing and the 

 Blood at Various High Altitudes. 

 By Mabel Purefoy EitzGerald. 

 (Communicated by J. S. Haldane, F.R.S. Received June 2, — Read June 25, 1914.) 



In a previous investigation carried out in connection with the Anglo- 

 American Pike's Peak Expedition (1911), the changes in the breathing and 

 the blood at high altitudes were recorded at atmospheric pressures ranging 

 from 625 to 458 mm. of mercury. Lack of time prevented further 

 observations being made, and in the graphic representation of the gases of 

 the alveolar air and of the percentage of haemoglobin in the blood 

 subsequently published,* the supposed values for atmospheric pressures 

 ranging from 625 to 760 mm. of mercury were indicated by a broken line. 



To complete the records, experiments were made by me in North Carolina, 

 U.S.A., during the months of July, August, and September of 1913. Three 

 localities were chosen in the Southern Appalachian chain, approximately 

 between 35° and 35° 6' N. latitude, and 82° 5' and 83° 25' W. longitude: 

 Highlands (altitude 3850 feet), the highest village east of the Rocky 

 Mountains, situated in the Blue Ridge Mountains ; Waynesville (altitude 

 2645 feet) in the Balsam Mountains, and Asheville (altitude 2210 feet) 

 situated in the valley of the French Broad River, with the Blue Ridge 

 Mountains lying to the south and east, and the foot-hills of the Unaka 

 Mountains to the west and north. 



Experiments were made with 43 residents. Care was again taken to 

 exclude the unhealthy, and those who, on account of recent change of 

 abode, might be unacclimatised. Observations were also made on myself 

 at each locality visited. 



The research is based upon 206 C0 3 determinations and 52 hamioglobin 

 percentage determinations. The subjects were adult men and women, of 

 from 18 to 70 years of age. The number of subjects corresponding to 

 each decade, or part thereof, were as follows : — 



Age. Number. 



Between 15 and 19 years 8 



„ 20 „ 29 „ 15 



30 „ 39 „ 14 



40 „ 49 „ 1 



» 50 „ 59 ,, 2 



. „ 60 „ 69 „ 4 



* ' Phil. Trans.,' B, vol. 203, pp. 351-371. 



