OF 



THE ^ESPIR:^TORY O^GsU^TS. 



:&CVTE PZEVSilSY. 



Eacli lung Is invested, upon Its external surface, Ijy an exceedingly del- 

 icate membrane, the pleura, wMcli incloses the organ as far as its root, 

 and is then returned upon the inner surface of the chest. The inner siu-- 

 &ce of the pleura is smooth, polished, and moistened by a fluid -which 

 favors the easy play of the surfaces, as the lungs alternately expand and 

 collapse in movements of respiration. 



In inflammation of this membrane or pleurisy, this lubricating fluid dis- 

 appears, and the surEaces become roughened, hot, swollen, and painful as 

 they come in contact and rub together with every inspiration. This con- 

 dition rarely exists longer than twenty-four hours, and oftener a much 

 shorter time ; then follows an effusion into the affected side, the space 

 being in some instances only partially filled, and iu others the amount of 

 fluid is of sufficient quantity to flU the cavity of the pleura, compressing 

 the lung into a small, solid mass. In certain cases of acute pleurisy which 

 pursue a favorable course, absorption of the liciuid commences a few days 

 after the accumulation has reached the maximum. Should the quantity 

 remain stationary, or the diminution take place very slowly, after the 

 elapse of two or three weeks, the disease becomes chronic. 



Pleurisy is an unilateral disease, that is, it affects the pleura of one side 

 only. While it may be associated with pneumonia (plenro pneumonia), it 

 does not tend to the development of that disease. 



Causalion. — Acute pleurisy may be produced by contusions, especially 

 if accompanied with fracture of the ribs, and penetrating wounds. It is 

 remarkable, however, that severe injuries of the chest often occur without 

 giving rise to this disease. Cold resulting from exposure. Is the more fre. 

 quent source of pleurisy. It may, however, be spontaneous, that is pro- 

 ceed from an unknown internal cause. 



Symptomt. — The attack is usually sudden. In a certain proportion of 

 cases, however, some pain or soreness exists one, two, or three days before 

 the development of acute inflammation. It is sometimes ushered in with 

 a chill, as shown by shivering. Pain in the affected side attends the onset 



