376 



THE RESPIRATION 



toms are less marked when the barometric pressure is reduced than when 

 the oxygen percentage is simply diminished. 



The Symptoms During Gradual Reduction of the Percentage of Oxy- 

 gen. Measurements have been made of a number of physiological func- 

 tions in a large number of healthy young men who were condidates for 

 the flying corps of the various armies participating in the recent war. 



* -*'- 



7?5H /N UEC/L. P7? M/N. 



180 



160 



140 



TOO 



80 



60 



40 



_. 



4 6 8 10 11 M- 76 18 W 



14 26 3L8 30 



" JB.H 



Fig. 130. The behavior of the respiratory volume, the blood pressure, and the pulse during 

 progressive anoxemia. 



The results are of value in showing to what extent the candidates can be 

 expected to withstand the rarefied air met with at great altitudes. The 

 accompanying chart (Fig. 130) taken from the "Air Service Manual" 

 of the United States Army depicts the results obtained on a perfectly 

 normal individual. The percentage of 2 in the air breathed at vari- 

 ous stages of the test is read on the right edge of the chart by find- 



