2 ANATOMY OF THE LYMPHATIC SYSTEM. 



of Recklinghausen ; and 3. The free communication between the 

 lymphatic vessels and the serous cavity by means of stomata. 



The following description refers to the minute structure of the 

 omentum, the centrum tendineum of the diaphragm and the pleura 

 mediastini. In dealing with these membranes we shall be able, 

 besides other important facts, to instruct ourselves about the three 

 questions above mentioned. 



In this Section I. we shall treat separately (1) of the endothelium 

 of the free surface, (2) of the cellular elements of the ground-sub- 

 stance, (3) of the lymphatic vessels, their distribution and relation 

 to the tissue and the surface, as well as their development, and (4) 

 of the blood-vessels. 



