HYGIENE IN RELATION TO BREATHING 173 



b. It is better for work, since a person can accomplish more 



in a given time when breathing outdoor air than when 

 breathing indoor air. 



c. It is better for health, even to sleep out of doors. 

 Nose-breathing is in every way better than mouth-breathing. 



a. Where mouth-breathing is due to adenoids, these growths 



should be removed. 



b. Where mouth-breathing is due to bad habits, these habits 



should be corrected. 

 Deep breathing is better than shallow breathing. 



a. Where shallow breathing is due to improper clothing, the 



clothing should be changed. 



b. Where shallow breathing is due to habit, correct habits 



should be acquired through exercise, outdoor games, 

 work, etc. 



Dust is a source of danger to the health of the body and to 

 the lungs in particular. 



a. Mechanical dust, soot, and smoke (including tobacco smoke) 



coat the lining of the air sacs and reduce the breathing 

 surface. 



b. Hard dust may scratch the lining of the air sacs and thus 



increase exposure to infection. 

 Dust carrying microbes is a direct source of danger. 

 Chemical dust and fumes may poison the blood. 



5. A person suffocated or drowned is not to be given up for dead 



before every possible effort to resuscitate him has been made 

 in vain. 



6. Ventilation is necessary not only to keep down the proportion 



of CO 2 and to keep up the proportion of oxygen in the air, 

 but also to (a) regulate the moisture, (b) regulate the tem- 

 perature, (c) keep the air moving, (d) remove disagreeable 

 odors, (e) remove gases and fumes, (/") remove dust. 



7. Alcohol, by congesting the capillaries, decreases the breathing 



efficiency of the lining of the air sacs. 



