26 ELEMENTS OF HISTOLOGY. [Chap. iv. 



lies the nucleus, and around it is a substance which 

 appears granular, but which is of a fibrillar nature, 

 the fibrillse being arranged in a network, and extend- 



Fig. 18. Network of Lymphatics in the Central -Tendon of the 

 Diaphragm of Rabbit, prepared with nitrate of silver, so as to show 

 the outlines of the Endotheiial Cells forming the wall of the 

 Lymphatics. 



a, Large lymphatic vessels; 6, lymphatic capillaries; c, apparent ends of the 

 capillaries. [Handbook.) 



ing in many places up to the margin of the ground- 

 plate. The nucleus is limited by a membrane, and 

 contains a well-developed reticulum. The nbrillse of 

 the cell substance appear to be connected with the 

 nuclear reticulum. 



31. As regards shape, endothelial cells differ 

 considerably. Those of the pleura, pericardium, 

 peritoneum, and endocardium of man and mammals 



