Diseases of the Respiratory System 153 



When the head passages are not filled with mucus the ap- 

 plication of the oil to the nostrils and argyrol to the eyes 

 without the previous steps is very beneficial. 



Prog72osis. — ■ A great majorit}' of the birds recover in a few 

 days if the cause is immediately removed. If the cause con- 

 tinues to act they may become worse and die, or the disease 

 may become chronic and persist for a long time. 



Bronchitis, Croup 



This disease may follow catarrh as a direct extension 

 of the inflammatory processes in the membrane of the 

 nasal cavities and throat to the mucous membrane of bron- 

 chial tubes. 



Diagnosis. — The symptoms of bronchitis are the symptoms 

 of a hard cold (severe catarrh) with rapid breathing and 

 cough. It may be distinguished from a cold by the peculiar 

 sounds made in breathing. In the early stages of the disease 

 this is a whistling sound made by the passage of the air 

 over the dry, thickened membrane. As the disease advances 

 mucus collects in the tubes and the breathing is accompanied 

 by a rattling or bubbling sound. Under favorable conditions 

 the symptoms do not usually pass beyond this stage but soon 

 disappear. In very severe cases the birds become very sleepy 

 and refuse to eat. The wings droop. The feathers are 

 roughened and breathing becomes more and more difficult, 

 until finally the bird dies. The less severe forms of the dis- 

 ease may become chronic, while the symptoms of rattling 

 breath and coughing up mucus may persist for a long time. 

 In this form of the disease the birds appear well except for the 

 above symptoms. 



Etiology. — When it follows a hard cold, bronchitis may be 

 caused by an extension of the inflammation of the mucosa of 

 the throat to the mucosa of the bronchial tubes. It may also 



