THE LYMPHATIC VESSELS OF THE SEROUS MEMBRANES. 43 



the diaphragm, we find in most cases a complete injection of the 

 lymphatics. In healthy guinea-pigs the injection is hardly ever so 

 complete as in rabbits. 



From Eecklinghausen it is well known that the very abundant 

 lymphatics of the centrum tendineum are distinguishable into lym- 

 phatic trunks and lymphatic capillaries, the former being provided 

 with valves and lined by spindle-shaped endothelium, the latter by 

 their variable lumen, the numerous excavations, their want of valves, 

 and their sinuous endothelium. Recklinghausen states that some of 

 the lymphatic capillaries of the pleural serosa terminate blindly, like 

 a horn curved inwards, and that they dissolve themselves at these 

 places in the lymph- canalicular system. Ludwig and Schweigger- 

 Seidel have further shown that the lymphatics of the pleural serosa 

 of the centrum tendineum of the rabbit stand in communication with 

 lymphatic vessels, which run between the tendon-bundles; these 

 being arranged in an abdominal radiating and a pleural circular 

 layer, the lymphatics which run between them have, consequently, 

 a radiating and circular course, and the former are called by L. and 

 S.S. superficial, the latter, deep lymphatic channels. My researches 

 teach me the following as regards the distribution of the lymphatics 

 in the rabbit : the lymphatics of the centrum tendineum are for each 

 half arranged in two systems, an anterior and posterior. The vessels 

 of the anterior system are distributed upon the outer and anterior 

 (that is larger) portion of the anterior quadrant, and upon the outer 

 (that is smaller) portion of the posterior quadrant. Those of the 

 posterior system are distributed upon the inner posterior (that is 

 smaller) portion of the anterior and upon the inner (that is larger) 

 portion of the posterior quadrant. (The relative number of lymphatics 

 is greater in the posterior quadrant than in the anterior). The 

 efferent trunks of the anterior system course along the pars costalis 

 of the diaphragm, and unite on the posterior surface of the xiphoid 

 cartilage on each side, usually to one or two large vessels, which run 

 along with the mammary vessels towards the sternal gland. On their 

 way they join with those lymphatics that come from the intercostal 

 spaces. It may be mentioned that the sternal gland is found gene- 



