CHRONIC PLEURISY. 



Animals liable. Causes, irritation through effusion and exudate acting on 

 susceptible pleura, or by other disease products in lung or pleura. Unhy- 

 gienic surroundings and management predisposes. Frequent chills in cold 

 water. Symptoms, unthriftiness, easily blown, fatigued, or sweated, cough, 

 paroxysmal under exertion, pallor of mucous membranes becoming congest- 

 ed on slight exertion, difficult breathing when recumbent, percussion and 

 auscultation signs of pleurisy and hydrothorax. Lesions, great liquid effu- 

 sion, clotting on exposure, with much albumen and cell-forms. False 

 membranes partially organized. Treatment, tonic, diuretic, derivative, 

 diet nourishing, counterirritants, paracentesis. 



In all domestic animals acute pleurisy may merge into the 

 chronic form, the irritation being maintained by the presence of 

 the residuum liquid and the false membranes and adhesions which 

 interfere with the free dilatation of the chest. The pleura too, 

 having been once inflamed, retains an increased susceptibility to 

 such disturbing conditions. In other cases the affection is sympto- 

 matic of other chronic affections, as tuberculosis, glanders, and 

 neoplasms of various kinds. It has been seen especially in old, 

 weak and debilitated subjects, kept in confined, impure stables or 

 habitually exposed to undue cold and damp. Hence dairy cows 

 in unhygienic conditions, and hunting dogs, which plunge in wa- 

 ter when heated, are among the mo.st frequent victims. 



Symptoms are often obscure. The affected horse may be bright 

 and lively, .showing little respiratory disturbance unless under 

 exertion. Yet there is a general appearance of unthriftiness, with 

 erect, dry hair, hidebound, and a small, dry cough. Under work 

 there is hurried breathing, early exhaustion, ready perspiration, 

 and aggravation of the cough which then occurs in paroxysms. 

 Auscultation and percussion give characteristic signs according as 

 there may or may not be false membranes or effusion at particu- 

 lar points. It is usually bilateral in horses, unilateral in other 

 animals. 



In cows in addition to the corresponding symptoms, there is 

 pallor of the mucous membranes when at rest, quickly transform- 

 ed into congestion under exercise, suppre.ssion of the milk, and 

 weak heart beats unless when excited. In the advanced condi- 



267 



