2G6 DISEASES OF THE PLEURA. 



These changes occur in every form of pleuritis, whether effusion 

 take place in the pleural cavity or not, whether the latter be profuse 

 or scanty, contain much or little fibrin, or many or few pus-corpuscles. 

 It is to this source alone that pseudo-membranes and adhesions of the 

 pleura owe their origin. 



The most common forms of pleurisy are 



1. That in which no symptoms occur, excepting those just de- 

 scribed, and to which we may give the name of pleuritis sicca, dry 

 pleurisy, or pleurisy with purely nutritive exudation. It is true, that 

 we but rarely have opportunity to make anatomical examination of a 

 dry pleurisy in its earliest stage. However, whenever this has been 

 possible (Foerster), no free exudation has been found to exist, the out- 

 growths from the pleura just described forming the sole abnormity. 

 Besides this, however, very extensive adhesions of the pleura are often 

 found, which have formed almost without giving rise to any symptoms, 

 and this fact would indicate that they must occur without exudation, 

 for we find that very small exudations are accompanied by very great 

 pain. 



2. Pleurisy with scanty \ but very jibrinous, exudation. Such a 

 pleurisy we almost always see accompanying croupous pneumonia or 

 complicating chronic affections of the lungs. It may also occur as an 

 independent disease. Here the inflamed pleura, having undergone the 

 alterations above described, soon becomes coated by an extremely deli- 

 cate membranous coagulum of fibrin, which causes it to appear more 

 opaque, so that we cannot discern the injection, or ecchymosis of the 

 pleura itself, until we have scraped off the fibrin with the scalpel-handle. 

 In other cases, this very fibriiious effusion is somewhat more profuse, 

 and we may then observe upon the pleura a white deposit, half a line 

 or more in thickness, somewhat soft, and very much like a croup mem- 

 brane. Of course, the exudation in these cases was originally liquid, 

 and only coagulates at a later period; nevertheless, we are often unable 

 to find any liquid effusion besides the coagulated one in the cavity of 

 the pleura. When this form of pleuritis recovers, the fibrinous de- 

 posit, after undergoing fatty degeneration and liquefaction, is absorbed, 

 the outgrowths of the opposing surfaces of the pleura are brought into 

 contact, and adhesions generally ensue. 



3. Pleurisy with abundant sero-fibrinous exudation. The altera- 

 tions in the tissues of the pleura are usually very extensive in this 

 form of the disease, both upon the pulmonary and costal surfaces ; but, 

 in addition to this, an effusion of serum takes place in the pleural sac, 

 amounting, not unfrequently, to two or three, and, indeed, even to ten 

 pounds or more. This exudation consists of two components a yel- 

 lowish-green serum, and a quantity of coagulated fibrinous masses. 



