CANCER OF THE PLEURA. 295 



*ung, spleen, liver, and meninges. As we have already seen, the pa- 

 tient succumbs to the intensity of the fever in this malady, before the 

 tubercles undergo further metamorphosis. Miliary tuberculosis of the 

 pleura gives rise to no peculiar local symptoms. 



IL Tubercular granulations develop with far greater frequence in 

 the young false membranes which grow from the pleura after repeated 

 relapses of pleurisy. We have seen that rupture of small blood-ves- 

 sels is liable to occur during the inflammation which the new vegeta- 

 tions (profusely supplied as they are with large and delicately-walled 

 capillaries) have to undergo in a relapse of pleurisy. This accounts for 

 the haemorrhagic character of the exudation, which accompanies tuber- 

 culosis of pseudomembranes. It appears in the form of numerous nodu- 

 lar prominences, of about the size of a hemp-seed, which at first are 

 white, afterward acquiring a yellow color. It is this tuberculosis of 

 pseudomembrane which is best adapted for the study of the origin and 

 metamorphosis of tubercle ( Virchow). The symptoms of this form of 

 tuberculosis of the pleura are indistinguishable from those of a pleurisy 

 with hsemorrhagif exudation. 



CHAPTER V. 



CANCER OF THE PLEURA. 



CANCER of the pleura never occurs primarily, and only is met with 

 in advanced general cancerous infection, and where cancer has arisen 

 in other organs, and particularly in those adjacent to it. It most fre- 

 quently complicates cancer of the mamma, of the mediastinum, and 

 of the lungs, and arises with especial frequence after extirpation of 

 cancer of the breast. The pleura is then either perforated from with- 

 out, by cancerous deposits of the vicinity which sprout inward, in the 

 form of bulbous swellings, or else independent cancerous nodules 

 spring up upon the pleura, attaining the size of a fist, and presenting 

 a lardy, marrowy appearance, and a nodulated or more or less level 

 surface. Cancers of the pleura are full of cells, have very little con- 

 nective tissue, und belong to the class of medullary sarcoma. 



When the cancerous degeneration is somewhat extensive, a liquid 

 collects in the cavity of the pleura, which, as it were, stands midway 

 between inflammatory and dropsical exudation. It contains fibrin in- 

 deed, jut as we find it in other serous sacs, which have become the 

 seat of cancerous disease, but it does not coagulate until a late period ; 

 that is to say, we find no fibrinous deposit in the effusion, but, upon al- 

 lowing the liquid to stand after evacuation, it gradually precipitates 

 coagulating masses, often continuing so to do for days. (Hydrops lym- 

 ph aticus, Virchow) (Hydrops fibrinous of Vbgel.) 



