36o 



RESPIRATION 



dangerous effects of the rarefied air in balloon ascents ; and Paul 

 Bert proceeded to test this on himself in a steel chamber which 

 he had procured. The arrangement is shown in Figure 94. In this 

 chamber he not only studied in himself and others the subjective 

 and other effects of low barometric pressure when ordinary air 

 was breathed, but also showed that by breathing oxygen all these 

 effects could be prevented in man, down to very low pressures. 

 Figure 95 is a diagram showing the variations of pressure in one 



76 _ 

 70 . 



i 



60 _ 



so 



40 



30 

 25 _ 



80. 



70. 

 60, 

 50. 



10-20 



30 



^0 



50 



20 



30 



40 



50 



II- iO 



Figure 95. 

 Tracing showing Paul Bert's pulse rate during a decompression experiment 

 in his steel chamber. Upper line = barometric pressure in centimeters. Lower 

 line = pulse rate. At o the breathing of oxygen was begun and continued 

 till the end of the experiment. 



of his experiments, and the striking effect on his pulse when he 

 began the continuous breathing of oxygen. The oxygen abolished 

 at once the various symptoms, of which an account was given in 

 Chapter VI. 



I have frequently verified in steel chambers, and also when air 

 very poor in oxygen was being breathed, Paul Bert's statements 

 as to the effects of oxygen. He noted the sudden increase in ap- 

 parent brightness of light and loudness of sounds, the return of 

 powers of memory and of intellectual powers, etc. As illustrating 

 how even one who is perfectly familiar with the effects on vision 

 of rapid relief of anoxaemia may be deceived by the subjective 



