160 PRACTICE OF EQUINE MEDICINE. 



Subacute, or pleurisy with effusion, also called sero-fibrinous, 

 in an inflammatory process with a large amount of serum. This 

 is the form most frequently seen in the horse. 



Suppurative pleurisy, or empycema, is where pus-cells are 

 formed. 



Interstitial, or adhesive pleurisy, or chronic pleurisy, is where 

 new connective-tissue formations take place. 



What is the aetiology? 



Pleurisy is not infrequently met with in the young green 

 horses, in the dealers' stables. The dealers probably lose more 

 from pleurisy than any other disease — that is, as complications 

 from other diseases. 



Pleurisy is one of the most fatal diseases affecting the equine 

 race. 



It arises from traumatic injuries, a wound penetrating the 

 muscles in the intercostal spaces, or it may be secondary to other 

 diseases, as pneumonia, when it is called pleuro-pneumonia, or 

 pneumonia complicated with pleurisy. 



It may accompany blood diseases, as glanders, or it is often 

 epizootic where influenza is prevailing in some of its forms. 



It may also be caused by foreign bodies in the pleural sac, 

 blood, pus, or air in the sac, or, again, necrosis of the ribs or ver- 

 tebrae. 



Inflammation of these structures, with a secondary pleurisy 

 in some cases. 



Changes in the atmosphere often aid to cause pleurisy. It is 

 more generally a secondary disease; the animal may be suffering 

 with a laryngitis, and you think he will get well; but the fever 

 keeps high, and after a time subacute pleurisy is developed. 



Nowadays it is said to be caused by micro-organisms. 



What is the pathological anatomy of pleurisy ? 



The course of an inflammation of a serous membrane is — 

 hyperemia, followed by exudation of lymph, the effusion of fluid, 

 its absorption, and the adhesion of the membrane. For study, 

 pleurisy may be divided into three stages. 



The first stage, or dry stage, or stage of engorgement or con- 

 gestion. There is an irregular redness of the membrane, with little 

 specks of exudation, called coagulable lymph ; this can be produced 

 by an injection of oxalic acid. At first the membrane is dry, red- 



