Respiration 347 



Deep breathing should be practiced daily. This habit may be 

 promoted by exercise in various forms, such as brisk walking, 

 work, and games of different kinds. Persons working in an 

 atmosphere where dust prevails are likely to have the tissue 

 of the lungs injured, thus making them more liable to disease. 

 Soot and smoke are irritating to the throat as well as to the 

 lungs. 



Diseases of the Respiratory System. Colds and catarrh 

 are two of the most common diseases that attack the air tracts. 

 A cold is an inflammation, usually due to the presence of bacteria, 

 or tiny germs. It may occur in the nose cavity or in the throat. 

 If it attacks the larynx, it affects the vocal chords and causes 

 hoarseness. If it affects the tonsils, it produces tonsilitis. If it 

 extends to the bronchial tubes, it causes bronchitis, and when it 

 attacks the air sacs of the lungs, it produces pneumonia, a very 

 dangerous disease. 



Catarrh is also an inflammation of the mucous membranes of 

 the throat and nose and may extend to the inner ear, causing 

 deafness, or to other parts of the body, causing various disorders. 



Another disease that affects the respiratory system is tuber- 

 culosis, which may be prevented by proper attention to diet, method 

 of breathing, food, exercise, and rest. Diphtheria, still another 

 disease that" affects the throat and nose, is due to a specific form 

 of bacteria that has the power to produce a dangerous toxin, or 

 poison. In recent years this disease has been more or less con- 

 trolled by the injection into the blood of an antitoxin, a substance 

 that counteracts the poison. Whooping cough also affects certain 

 parts of the respiratory system. 



Ventilation. To ensure the proper ventilation of a room, 

 there should be a constant supply of fresh air, heated to a suitable 

 temperature, properly moistened, and an outlet to carry away foul 

 air. The supply of fresh air must be sufficient to replace the 

 oxygen taken up by the occupants of the room in respiration, and 

 to absorb and remove the carbon dioxide they give off. Recent 

 experiments indicate that under ordinary conditions, even when 

 ventilation is poor, the air will not become so unwholesome as has 

 heretofore been supposed, provided it is kept in motion and due 



