260 CLINICAL BACTERIOLOGY AND HiEMATOLOGY 



Some writers consider these cells to be growth-cells, but on 

 what grounds I do not know. When they form masses they are 

 always one cell thick, never solid alveoli ; and, more conclusive, 

 when an opportunity is obtained of examining the cells of the 

 growth post-mortem, they are often absolutely diiferent from 

 those found in the exudate during life. 



In yet other cases the endothelial cells are of the ordinary 

 passive type, but a suspicion of the nature of the growth may be 

 obtained from the number of red corpuscles present. 



" Mechanical " Exudates {i.e., those due to cardiac disease, 

 pulmonary congestion, or renal disease). — The deposit from the 

 exudate is usually very scanty, and consists of large flat masses 

 of passive endothelial cells, there being often many cells in 

 one large plate ; their outlines may be indistinct. There is 

 usually nothing else, but there may be a few red corpuscles or 

 leucocytes. 



Pleurisy Secondary to Infarcts. — Endothelial cells mixed 

 with much blood and with many polynuclear leucocytes have 

 been described, but I have no personal experience of the condition. 



Peritoneal Exudates. 



These are very equivocal, and often difficult or impossible to 

 interpret. The ultimate conditions leading to the production of 

 the cells are doubtless the same in the peritoneum as in the pleura, 

 but here the fluid is in close proximity to the intestine, and liable 

 to constant mild infective processes. These call forth a poly- 

 nuclear leucocytosis, Which is very common in ascitic fluid, and 

 devoid of the significance which it has in the pleura. 



Tuberculous Peritonitis may be accompanied by a pure 

 lymphocytosis, the cells becoming extraordinarily abundant, so 

 that the fluid may be turbid, or there may be polynuclears in a 

 practically pure state. I do not think the condition can be diag- 

 nosed unless tubercle bacilli are found. 



Septic Peritonitis. — The cells are all polynuclears except in 

 the early stages, in which a few endothelial cells and red corpuscles 

 may be found. The diagnosis is to be made by the discovery of 

 the organism, which is usually easy. 



Mechanical Ascites (i.e., that due to cirrhosis of the Hver, 

 renal disease, cardiac disease, etc.). — Here endothelial cells, often 

 in masses, are almost always present, and sometimes practically 



