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CHAPTER III. 



THE LYMPHATIC VESSELS OF THE SEROUS MEMBRANES. 



a. Lymphatics of the Omentum and the Pleura Mediastini. 



IN the rabbit's omentum the lymphatics are easily demonstrated. 

 Following the above-mentioned method, it is necessary only to pencil 

 in situ the surface of the fresh omentum and then to stain it in silver. 

 Different portions -of the omentum are differently circumstanced as 

 regards lymphatics. In the neighbourhood of the greater curvature 

 of the stomach, and in the portion of omentum covering its pyloric 

 end, there occurs a rich network of lymphatics : they are related to 

 the large blood-vessels in such a way that a group of the latter has 

 a lymphatic running along both sides and communicating with one 

 another by transverse and oblique lateral branches. The lymphatics 

 are also distributed independently of large blood-vessels, chiefly 

 between and around the lymphatic patches which, as mentioned above, 

 are met with in great abundance in this part (the pylorus and greater 

 curvature). Concerning their structure, there is little to add to what 

 is already known. They are wide vessels, the walls of which consist 

 only of one layer of endothelial plates ; the latter, in the large lym- 

 phatics accompanying the blood-vessels, being of a short spindle 

 shape, almost sinuous. These possess also valves and sacculated dila- 

 tations corresponding to them, and are to be considered as the main 

 lymphatic trunks. 



The other class, running apart in the tissue, are not different in 

 calibre, and have also a sinuous endothelium; but they are either 

 without valves or have them only in a very few places, while they are 

 provided with sinus-like dilatations springing from their sides. These 

 are to be considered as the lymphatic capillaries. 



