DESCRIPTION OF PLATE X. 



Fig. I. — Primary pleurisy, probably due to true rheumatism. 

 Wet preparation stained with methylene blue. The large 

 cells are "active" endothelial cells, many of which are 

 crowded with large retractile granules. Notice the different 

 degrees with which these cells have taken the stain. There 

 are also some polynuclears, lymphocytes, and red blood- 

 corpuscles. 



Fig. 2. — From a case of passive pleural effusion due to cardiac 

 disease. (The appearances in that due to renal disease are 

 identical.) Flat " passive " endothelial cells often grouped 

 into large plates, some much larger than those shown. A 

 few lymphocytes and red blood-corpuscles (the latter possibly 

 from the puncture). Film stained with carbol thionin. 



Fig. 3. — Cells from a case of ascites due to malignant disease 

 of the ovary. Huge endothelial cells, showing large clear 

 vacuoles. There are numerous red corpuscles, one of which 

 has been ingested by an endothelial cell. Carbol thionin 

 (On same scale as Plate IX.) 



