INFLAMMATION OF THE PLEURA. 267 



Part of the latter floats in the serum in the form of flakes and lumps, 

 another part traverses the serum in the form of a loose net-work, while 

 a third portion is precipitated upon the pleura, upon which it lies in 

 the form of a membrane. The longer the effusion remains, so much 

 the stronger and more rigid do the masses become, until they finally 

 grow fibrous, without, however, taking on any organization. Both 

 in the serum and in the fibrinous deposit we find a few pus-corpuscles, 

 so that the transition from this form of pleurisy to the next, in which 

 pus-corpuscles are far more abundant, is quite gradual. The greater 

 the quantity of pus, so much the more turbid is the serum, and the 

 more yellow the deposit. The proportion between the serum and the 

 fibrin varies, although here, too, we are not warranted in regarding 

 fibrinous exudation as the consequence of a hyperinosis (augmentation 

 of fibrin in the blood). Indeed, according to the old-fashioned theory, 

 it is far more probable that a pleurisy, in which a great amount of 

 fibrin is secreted in the pleura, also causes the increased quantity of 

 fibrin in the blood. The exudation often seems to receive accessions, 

 and to increase by fits and starts. As these after-flows do not come 

 immediately from the vessels of the pleura, but from the thin-walled 

 vessels of the young connective tissue, we often find an admixture of 

 blood in the serous effusion of chronic pleuritis, in consequence of rup- 

 ture of the delicate capillary walls, thus forming pleurisy with haemor- 

 rhagic exudation. We constantly find agglutinations of the opposing 

 surfaces by fibrinous exudation, as well as commencing adhesions, sur- 

 rounding the effusion, whereby the latter is often incapsulated. This 

 is a condition of great importance in the symptomatology of the 

 disease. 



According to the lucid and concise account of Rokitanslvy, the 

 changes which take place in the thorax and its contents, in consequence 

 of extensive effusion, are as follows: "The thorax is dilated in a 

 manner more or less apparent, the intercostal spaces are widened and 

 prominent, the diaphragm is forced down into the abdomen, the medi- 

 astinum and heart are displaced to the other side, or, when the effusion 

 is symmetrical, lie in the middle of the chest. The lung itself is com- 

 pressed to a degree corresponding to the amount of the effusion, and, 

 unless old adhesions offer resistance, it is constantly pushed upward 

 and inward against the mediastinum and back-bone. We find it re- 

 duced to the fourth, sixth, and even to the eighth part of its normal 

 volume, and flattened into a cake, its color is pale reddish or bluish 

 gray, or lead color, and its consistence is leathery, tough, and void of 

 blood and air, and in a state of atrophy at the edges and surface. It 

 is coated externally by the coagulum of fibrin, which extends from the 

 costal to the pulmonary pleura. In partial pleuritis, the displacement 



