DISEASES OF THE BRONCHI. 143 



specific fevers and under various other conditions depending 

 upon malliygienic conditions. 



Varieties. — Acute Bronchitis may be grouped under the 

 following varieties : (1) primary or idiopathic bronchitis, 

 which may involve the larger air-tubes or may extend to 

 their ultimate ramifications; (2) secondary bronchitis, or 

 bronchitis co-existing with specific fevers and other diseases 

 depending on an unhealthy condition of the system.; (3) 

 mechanical bronchitis, or bronchitis depending on noxious 

 vapours, fluids, or solids, irritating the lining membrane of 

 the tubes. 



1. Symptoms of Acute Bronchitis of the Large and 

 Small Tubes. — Acute bronchitis is usually ushered in with 

 chilliness, malaise, and febrile symptoms, though in many 

 cases these may be trivial. 



When fuWy developed, besides the symptoms of ordinary 

 catarrh, there is a frequent hard and sonorous cough, which 

 becomes softer as exudation into the bronchi increases in 

 the progress of the disease. The appetite is impaired and 

 the horse is dull and dejected. The pulse is increased and 

 is rather soft ; the respirations are much accelerated, being 

 relatively much higher than the number of pulse-beats. In 

 many severe cases indeed they are as numerous as the pulse, 

 and may even exceed it in number. 



Physical Signs. — Generally there is no alteration in per- 

 cussion in bronchitis, though there may be dulness over 

 portions of the chest where the lung is collapsed, owing to 

 obstruction to the passage of air in inspiration by inspis- 

 sated mucus, and also when pneumonia or other complica- 

 tions are present. In some instances of acute bronchitis 

 attended with much secretion, the percussion note is more 

 resonant than usual, owing to distension of the lung-tissue 

 with air. This condition sometimes proceeds to actual 

 emphysema. The breathing-sounds are coarse and noisy. 



