102 



PHYSIOLOGY. 



IN 10,000 VOLUMES. 



Represented by Large Square.) 



PER CENT. 



COMMON FRACTION 



AMOUNT OF CARBON 



DIOXID 



IN 



INSPIRED AIR. EXPIRED AIR! 



4 400 



(Small Square.) (Medium Square) 



.04 4 



1 



2500 



25 



2O 10O 



Fig. 45. Amount of Carbon Dioxid in Inspired and Expired Air. 



The Composition of Inspired and Expired Air. 



Oxygen. Nitrogen. Carbon Dioxid. 

 Inspired air . . . 21 79 .04 



Expired air ... 16 79 4 oo 



While the amount of nitrogen remains about the same, 

 some oxygen has disappeared, and its place is taken by 

 carbon dioxid, while the amount of carbon dioxid has in- 

 creased a hundred-fold 



