RESPIBATION. 243 



Q. Why are PERSONS so PALE who live in 

 CLOSE ROOMS and CITIES ? 



, A. The blood derives its redness 

 from the oxygen of the air inhaled ; but, 

 as the air in close rooms and cities is 

 not fresh, it is deficient in oxygen, and 

 cannot turn the blood to a beautiful 

 bright red. 



Q. Why are PEBSONS who live in the OPEN 

 AIR and in the country, of a RUDDY complexion ? 



A. As the blood derives its bright 

 red colour from the oxygen of the air 

 inhaled, therefore, country-people (who 

 inhale fresh air) are more ruddy than 

 citizens. 



Q. Why is not the air in CITIES so FRESH 

 as that in the COUNTRY ? 



A. Because it is impregnated with 

 the breath of its numerous inhabitants, 

 the odour of its sewers, the smoke of 

 its fires, and many other impurities. 



Q. How does the COMBINATION of OXYGEN 

 with the BLOOD produce animal HEAT ? 



A. The principal element of the 

 blood is carbon, which (combining with 

 the oxygen of the air inhaled) produces 



Y2 



