Without thinking, we work the muscles to draw up the ribs about eighteen times every minute, because all parts of the body are calling for oxygen. The harder we work the oftener we breathe because the muscles need more oxygen to make them go.
Why we should breathe through the Nose.—Most persons find it easy to breathe through the nose. In some, however, the passages in the nose are too small to carry the air without effort. On this account they let the mouth hang open and breathe through it.
Fig. 58 —Face cut through the middle to show how the adenoids stop the air from passing through the nose. Arrows show the course which the air should take.
The air should pass only through the nose because it is lined with hairs and tiny waving threads which catch the dust. In this way germs and dirt are prevented from getting into the throat and lungs, and in winter the cold air is warmed.
Why Some Children cannot breathe through the Nose.—When one has a cold, the lining of the nose becomes swollen and gives out a white substance called mucus. The swelling of the lining and the mucus fill up the passages. The nose should be kept clean by using a handkerchief and blowing out the mucus into it. Never put the finger into the nose. Disease germs often get on the fingers from things touched.
Children who have the habit of breathing through the mouth should be examined by a physician. He will, in most cases, find soft spongy growths called adenoids in the back part of the nose. They should always be removed as soon as possible. They may cause disease or deafness and may even injure the mind.
