218 THE DOG IN DISEASE. 



not easily detected. Various injuries, as fracture of the 

 ribs, also induce it. 



Pathology. — Dryness of the membrane, followed by 

 increased secretion of an altered material, either perma- 

 nently fluid or with a tendency to coagulate — "plastic 

 lymph." The fluid may or may not be absorbed, and the 

 semi-solid matter disappear or become organized and cause 

 adhesions, limiting the action of the lungs, which is one 

 of the gravest results ; or the fluid produced may be puru- 

 lent — also a very serious state of things. 



Prognosis. — As a simple disease and not a complica- 

 tion, with but little effusion, and in the absence of pus, 

 the prognosis is good j otherwise uncertain. 



Diagnosis. — The differential diagnosis is between 

 bronchitis and pneumonia, chiefly the latter. 



The pain, the shallow, quick, catchy breathing, the 

 anxious expression, possibly tenderness on percussion, and 

 especially the " friction sound " heard on auscultation, with 

 absence of dullness at the same time, make the diagnosis 

 pretty certain. 



The temperature is not usually as high as in pneu- 

 monia. 



Of course, in the latter disease we get at the outset 

 more or less dullness and altered respiratory sounds, which, 

 as the disease progresses, become more pronounced, till 

 there is positive " wooden dullness " on percussion, with 

 the total absence of respiratory sounds over that region, 

 and intensified sounds with "blowing" or "bronchial" 

 breathing elsewhere on the affected side. 



The difficulty in diagnosis is only in the earliest stage, 

 before the physical signs of pneumonia are well estab- 



