RESPIRATORY SYSTEM 353 



son is large, and a good deal of air enters through the 

 cracks around the windows and the doors. But even 

 so, out-of-door air is far superior to the air in houses. 

 Unfortunately in most dwellings little provision has 

 been made for proper ventilation. Most of us depend 

 entirely upon open windows. If one window is opened 

 at the bottom to let fresh air in, and another at the 

 top to admit of the escape of the warm foul air, this 

 method works pretty well. It does, however, often 

 produce drafts, and as a rule cools the air too much. 

 Fresh air does not necessarily mean cold air. 



In tenement buildings, public halls, and work shops 

 much more attention should be given to ventilation. 

 Certainly each of us has had the experience of being 

 made very uncomfortable because of poor air. Air 

 itself will not circulate very rapidly. Consequently 

 in large buildings it is necessary to have it forced into 

 the rooms by large fans in the basements. It is best 

 to have fresh air brought in from the out-of-doors, have 

 it Avashed to remove the dust, then heated, moisture 

 added, and fanned around to the rooms. It is well to 

 have this warm air enter at the top of the room. 

 Then as it cools and becomes foul it settles to the lower 

 part of the room from which it should be removed. 



Diseases of the respiratory organs. There are many 

 diseases which attack one or more parts of the organs 

 used in breathing. Many of these are the so-called 

 "impure" air diseases, while others have a different 

 origin. 



