INSPIRED AND EXPIRED AIR. 



'121 



because not well known, highly putrescible, often called by 

 the general name of " organic waste matter." 



Let us compare the inspired and expired air in its compo- 

 sition. 



//V.10OOO 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 



1 

 2500 



4 



1 

 25 



2 2O 



Fig. 47. Amount of Carbon Dioxid in Inspired and Expired Air. 



100 



Inspired air contains in one hundred parts, as compared 

 with expired air : 



Oxygen. Nitrogen. Carbon Dioxid. 

 Inspired air . . . 21 79 .04 



Expired air . . . 16 79 4.00 



