BREATHING IN MAN 



151 



1. It looks hideous to other people; no one likes the 

 appearance of a mouth-breather (see Fig. 49). 



2. It sounds bad at night. That is, the mouth-breather is 

 likely to become a snorer. Snoring is the sound produced by 

 the vibration of the soft palate when a current of air strikes 

 it on the way out through the mouth. You don't snore when 

 you are awake ; but when you are asleep the muscles of the 

 mouth and palate relax, and the air sets the palate in motion. 



182. Obstructions in nasal 

 passages. When children are 

 seen to breathe through their 

 mouths, and difficulty is found 

 in making them breathe through 

 their noses, they should be ex- 

 amined by a physician, as it is 

 likely that there is some ob- 

 struction in the nasal passages. 

 The most common obstruction 

 is an outgrowth of the lining 

 in the back part of the nostrils ; 

 such growths are called ade- 

 noid growths, and when present 

 should be removed (see Fig. 

 50). Their presence is a handi- 

 cap to the child, since it inter- 

 feres with proper breathing 



and, sometimes, with the circulation of the blood in the head. 

 It is true that if they are not cut out, they are likely in time 

 to disappear, being gradually absorbed. But by the time they 

 are absorbed, the harm will have been done, for the growth and 

 mental development of the child will have become permanently 

 retarded by just so much. 



183. Deep breathing. A second factor in breathing is that 

 of depth. In ordinary breathing a man at rest takes into his 

 lungs and throws out again with each breath about 30 cubic 



Fig. 50. Adenoid growths 



In the passage between the nostrils and 

 the pharynx (/) shapeless masses of tissue 

 {a) sometimes grow out, obstructing the 

 movement of air from the nose and lead- 

 ing to mouth-breathing. /, the larynx, or 

 voice box 



