DRY PLEURISY IN THE HORSE AND OX. 



Definition. This is a form of pleurisy in which the exudate 

 coagulates at once on the inflamed surface, and no appreciable 

 amount of liquid is thrown out. For this reason probably, the 

 infection does not extend widely and it is manifested by clear, 

 glistening, white patches varying in size from one to six inches 

 in diameter, and usually firm and resistant. In its lactescent 

 color it is in marked contrast with the rosy red of the adjacent 

 serosa. Occurring mainly in old animals, it implicates by prefer- 

 ence the outer side of the lung in the region of the heart or near 

 its upper border, and often establishes an adhesion between this 

 and the ribs, the diaphragm, or in cattle between lobe and lobe. 

 In some cases the membranes are shreddy as if they had been torn 

 from their adhesions. If recent these membranes are granular 

 or fibrillated ; if of older standing they have become firm, fibroid 

 and tough. They may bind the lung closely and immovably to 

 the ribs ; or they may be loose, mobile, and allow the free move- 

 ment of the one on the other. 



Causes. Many cases appear to be the result of a constitutional 

 condition, like rheumatism, occurring at points where external 

 injuries could have little effect (under the muscular shoulder or 

 back) . Yet Cadeac draws attention to cases in which fistulous 

 withers have been attended, as shown post mortem, by inflamma- 

 ,-tion and the formation of false membranes on the pleura just 

 beneath. Chronic pneumonia occurring in old animals seems to 

 be especially subject to the complication of dry pleurisy. Again, 

 tumors in the lung and comparatively inactive pulmonary tuber, 

 culosis, are subject to this pleuritic complication. Yet dry pleu- 

 risy appears at times to come from the same general causes as 

 sero-fibrinous pleurisy, acting perhaps on a system with a special 

 insusceptibility, 



Symptoms. These are in the nature of things obscure. The 

 disease is usually circumscribed in area, and limited to points 

 where the movements of the lung are most restricted, and the 

 surface most deeply covered by the bones and thick muscular 

 masses of the shoulder or back, so that in some cases, in the ab- 

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