MOUTH BREATHING 55 



not to get into the lungs. The nose is provided with small 

 hairs and a moist inner membrane which serve as filters in re- 

 moving solid particles from the air, and in thus purifying it 

 before its entrance into the lungs. 



In the immediate neighborhood of three Philadelphia high 

 schools, having an approximate enrollment of over 8000 pupils, 

 is a huge manufacturing plant which day and night pours forth 

 grimy smoke and soot into the atmosphere which supplies oxy- 

 gen to this vast group of young people. If the vital impor- 

 tance of nose breathing is impressed upon these young people, 

 the harmful effect of the foul air may be greatly lessened, the 

 smoke particles and germs being held back by the nose fil- 

 ters and never reaching the lungs. If, however, this principle 

 of hygiene is not brought to their attention, the dangerous habit 

 of breathing through an open, or a partially open, mouth will 

 continue, and objectionable matter will pass through the mouth 

 and find a lodging place in the lungs. 



There is another very important reason why nose breathing 

 is preferable to mouth breathing. The temperature of the 

 human body is approximately 98 F., and the air which enters 

 the lungs should not be far below this temperature. If air 

 reaches the lungs through the nose, its journey is relatively 

 long and slow, and there is opportunity for it to be warmed 

 before it reaches the lungs. If, on the other hand, air passes 

 to the lungs by way of the mouth, the warming process is brief 

 and insufficient, and the lungs suffer in consequence. Natu- 

 rally, the gravest danger is in winter. 



Cause of mouth breathing. Some people find it difficult 

 to breathe through the nostrils on account of growths, called 

 adenoids. If you have a tendency toward mouth breathing 

 (Fig. 27), let a physician examine your nose and throat. 



Adenoids not only obstruct breathing and weaken the whole 

 system through lack of adequate air, but they also press upon 



