796 



CMAXGE OF COMPOSITION OF ALVEOLAR AIR, 



bag. If the rate at which the alveolar tension of carbon dioxide 

 rises, and that at which the alveolar tension of oxygen falls, be 

 the same, when the contents of the lungs are breathed in this way 

 as when the breath is held, the changes in the tensions of the gases 

 will be about 3% less in the former case than in the latter. 

 The figures given in the following Table, however, show that, on 

 the contrar\', the changes in the tensions of the gases are con- 

 siderably greater in the former case. 



Table ii. — Composition of alveolar air after hreafliiii;/ into and out of 

 dosed hay for narious periods. 



