128 LYMPHATIC SYSTEM. 



ments of the lymphatic endothelium. The canalicular cells are 

 also in communication with the flat cells which form the layer 

 immediately covered by the serous endothelium. 



The anatomical relation of the caualiculi and tymph cells on 

 the abdominal side are the same as in the pleura. To demon- 

 strate them, the abdominal surface of the centrum tendineum 

 is prepared in the same way as last described. In the neigh- 

 borhood of the large vessels, the existence of a similar layer of 

 flat elements lying underneath the serous endothelium, resem- 

 bling in character those already described in the pleura, can be 

 demonstrated. The canaliculi and lymphatic cells of the pro- 

 prici have also the same relation to each other and to the super- 

 ficial network of lymphatic capillaries as in the pleura. Finally, 

 it is to be mentioned that in the tissue which occupies the 

 fascicular channels which contain no lymphatics, the same 

 character can be observed. Here the continuity of the lym- 

 phatic cells with the similar cells of the tendon-tissue, which, 

 as we have seen, are oblong branched placoids, and apply 

 themselves to the surfaces of the primitive bundles of fibrils, 

 can be demonstrated. 



Pseudo-Stomata. In examining carefully the pleura! sur- 

 face of a diaphragm which has been treated with nitrate of 

 silver, without pencilling, it is seen that there are here and 

 there spaces between the endothelial elements which are occu- 

 pied by bodies of a more or less branched contour. These are 

 usually darker in color than the endothelium of the surface, 

 and often exhibit distinct nuclei. If the preparation has been 

 partly pencilled, it is often possible to observe, at the junction 

 of the pencilled and unpencilled part, that the bodies in ques- 

 tion are of the same kind with the flat branched cells which 

 are covered by the endothelium ; and it can be also made out 

 that even where they are covered, the cells of this layer send 

 up projections between the endothelial cells which reach the 

 surface. These projecting cells may be called pscudo-stomata. 

 The intimate relation which exists between the sub-endothelial 

 cells and those of the propria, and between these last and those 

 which line the lymphatic vessels, has been already referred to. 

 That these cells are also concerned in absorption is indicated 

 by the fact that, in chronic inflammation, and other conditions 

 in which absorption from the serous surface is more than usually 

 active, these pseudo-stomata and the canaliculi are the seat of 

 germination and that if coloring matter in a state of fine 

 division has been previously introduced into the peritoneum, 

 they are found to contain it. 



Lymphatic System of the Omentum and Mesen- 

 tery. To demonstrate the lymphatic structures of the omen- 

 turn, the peritoneal cavity is opened in a rabbit just killed. The' 

 large and small intestines having been pushed aside to the 



