IMPURE AIR 



183 



number of prisoners were crowded into a dungeon with 

 but one window, all of the men, except those few who 

 were able to crowd close to the window, were found 

 dead in the morning. The effects of bad air are further 

 shown by the wonderful improvement in health and 

 strength which a change to out-of-door life in the pure 

 air makes among those who have been confined in close 

 rooms. Even when consumption has obtained a foot- 

 hold, the fresh air life not only stops the progress of 

 the disease but even cures it. 



Odor a test of impurity. Careful studies have 

 shown that whenever the air of an occupied room has 

 .a close or offensive odor to a person coming into the 

 room from the outside air, it is unwholesome and even 

 poisonous to those breathing it, however unconscious 

 they may be of it. Indeed, the worst danger of bad air 

 lies in the fact that its effects are so general in char- 

 acter and accumulate so slowly from day to day that its 

 victims do not know why they are weak, pale and gen- 

 erally miserable. 



Amount of fresh air required. Many chemical 

 tests have been made of the air of crowded rooms, 

 halls and shops, in which the occupants were sleepy, list- 

 less and given to headaches. The air has invariably 

 been found to be offensive to a person entering from 

 the outside air and to contain large amounts of carbon 

 dioxide from the breath. The presence of 2 parts of 



TEST BY ODOR OF AIR OF AN OCCUPIED ROOM 



