CHAPTER III. 

 DISEASES OF THE BRONCHI. 



CATARRHAL BRONCHITIS. 



Definition. — By the term bronchitis an inflammation of the 

 larger bronchi is understood (macrobronchitis) . Bronchio- 

 htis (microbronchitis) is used to express an inflammation of 

 the capiflary bronchi (bronchitis capillaris) . 



Occurrence. — ^Bronchitis occurs either as a primary or 

 secondary disease. It is very common among all domesti- 

 cated animals particularly during the spring and fall when 

 it may become enzootic among horses and cattle. It may 

 occur alone but is usually associated with tracheitis and 

 laryngitis (catarrh of the air passages), or on the other hand 

 may attend pneumonia (bronchopneumonia) . 



Forms. — Several difl^erent forms of catarrhal bronchitis 

 are recognized. When the exudate is fluid and abundant, 

 moist bronchitis or blenorrhea of the bronchi is spoken of. 

 If the exudate is rather limited and not so fluid a dry bron- 

 chitis exists. A fetid bronchitis develops from a bacterial 

 decomposition of the exudate. From the standpoint of 

 course, catarrhal bronchitis may be either acute or chronic, 

 and from the causes a verminous and a mycotic bronchitis 

 may be distinguished. 



Etiology. — ^The causes are usually refrigeration (changeable 

 weather), inhalation of mechanical and chemical irritants 

 (dust, smoke, chemical fumes), aspiration of fluids such as 

 liquid medicines unskilfully administered, blood, pus or 

 solid matter such as food which gains access to the windpipe 

 especially when the pharynx is paralyzed. Certain animal 

 parasites (strongylus) and bacteria are also causes. 



Secondary bronchitis occurs with most of the infectious 

 diseases affecting the respiratory tract (influenza, strangles, 

 tuberculosis, hog-cholera) , 



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