28 



ELEMENTS OF HISTOLOGY. [Chap. iv. 



i.e., scaly but in some places they are polyhedral, 

 or even short columnar. Such cells occur isolated or 

 in small groups, or covering large and small patches, 

 nodular, villous, or cord-like structures of the pleura 



Fig. 20. Part of Peritoneal Surface of the Central Tendon of Diaphragm 

 of .Rabbit, prepared with Nitrate of Silver. 



s, Stomata ; Z, lymph-channels ; t, tendon bundles. The surface is covered with 

 endotheiium. The stomata are surrounded by germinating endothelial cells. 

 (Handbook.) 



and omentum, on the synovial membranes, tunica 

 vaginalis testis, &c. They are especially observable 

 in considerable numbers in the pleura and omentum 

 (Fig. 19) of all normal subjects (human, ape, dog, cat, 

 and rodent animals); their number and frequency of 

 occurrence are increased in pathological conditions 

 (chronic inflammations, tuberculosis, cancer, &c.). 



These endothelial cells are the germinating endo- 

 thelial cells, and they can be shown to be in an 



