DISEASES OF THE LUNGS. 161 



In the second stage the respiratory murmur is replaced by 

 the very characteristic tubular or hroncliial breathing. In 

 some instances there is a total absence of breathing sounds 

 in this stage, and the fine crepitations are not heard. 



In the third stage of an ordinary attack ending in resolu- 

 tion, the bronchial breathing gradually gives place to crepi- 

 tation of a moist coarse character, termed redux, or secondary 

 crepitation, and this gradually passes into the ordinary 

 bronchitic rales. 



Pleural friction may be heard in addition to the sounds 

 due to the pneumonia, when this disease is complicated with 

 inflammation of the pleural membranes. 



Acute pneumonia, especially when associated with bron- 

 chitis, is said to be sometimes complicated with laminitis, 

 or inflammation of the vascular structures of the feet. 



When pulmonary inflammation occurs as a secondary 

 affection, especially when associated with some specific 

 fever, or when the animal has been subjected to malhygienic 

 and debilitating conditions, the attack is very apt to assume 

 the adynamic or asthenic type, and is more likely to end in 

 breaking down of the pulmonary tissues than in resolution. 



Under such circumstances the pulmonary inflammation is 

 more of the catarrhal or lobular type, which is chiefly 

 characterized by filling of the alveoli with cells derived from 

 the epithelium lining them, and by the fact that exudation 

 and emigration play a much less prominent part in the 

 process than they do in croupous pneumonia. Catarrhal 

 pneumonia terminates by gradual defervescence of the 

 febrile symptoms, or lysis, as it is termed. 



Prognosis. — Is favourable in most instances. Pneumonia 

 may prove fatal from the intensity of the fever in the early 

 stages, and also during the stage of hepatization, from 

 suffocation occurring as the result of the pathological 

 changes. In double pneumonia, or inflammation of both 



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