126 THE WONDERFUL HOUSE THAT JACK HAS 



a room sixteen feet long, twenty feet wide, and nine 

 feet high make the atmosphere impure in an hour, 

 provided there is no ventilation. Two persons sleep- 

 ing in a closed bedroom ten feet long, ten feet wide, 

 and eight feet high, make the air unfit for respiration 

 in less than two hours. During this short period 

 several ounces of watery vapor containing noxious 

 waste particles of matter have been given off from the 

 lungs and skin. If a third person should come from 

 pure atmosphere into such a room, the odor would 

 be. almost unbearable. The sleepers' noses, however, 

 having become accustomed to it gradually, do not 

 warn them of the dangerous and disgusting air they 

 are breathing. 



We know people are often in close rooms several 

 hours at a time without meeting any quickly fatal 

 results. What, then, is the harm ? Impure air dulls 

 the senses, and also makes one physically restless and 

 uneasy. Often when pupils are stupid and inattentive 

 in school, the air, not the lack of brains or desire to 

 learn, is to blame. There is no better aid to successful 

 teaching or preaching than plenty of pure, fresh air. 

 Wise, indeed, are the teachers and preachers who 

 realize this fact. When the normal supply of oxygen 

 is reduced in the air we breathe, too much carbonic 

 acid gas and waste tissue are retained in the blood ; 

 and on this account all the organs and functions of 

 the body are impaired, for the time being at least. 

 When the use of such air is frequent, the vigor and 



