46 ANATOMY OF THE LYMPHATIC SYSTEM. 





 deep straight lymphatic capillaries and the superficial ones represent, 



as we have seen, only one category of vessels, we are justified in saying 

 that this category of lymphatic capillaries discharges itself in two 

 directions : one freely in the thoracic duct, and a second less freely 

 towards the sternal gland. In a following chapter we shall see 

 that the straight lymphatic capillaries, the deep ones as well as the 

 superficial ones, stand in free communication with the peritoneal cavity, 

 by means of vertical lymphatic canals "(stomata of the authors) ; 

 consequently, we have to substitute for the diagram of L. and S.S. 

 representing the lymphatics as a single pump, a diagram of a pump 

 with two cylinders, the one cylinder corresponding to the pleural 

 vessels of the anterior system, the other to those of the posterior 

 system, while the pipe connecting the two cylinders is represented 

 by the straight capillaries, and the piston tube by the vertical 

 lymphatic canals. It must be borne in mind, however, that the two 

 cylinders act simultaneously. 



The superficial straight lymphatic capillaries are not. the only 

 capillaries that are to be met with on the abdominal surface of the 

 centrum tendineum of the diaphragm of rabbits and guinea-pigs. 

 Near the median line of the anterior quadrants, and near the large 

 blood-vessels that pass through the diaphragm, there exist lymphatic 

 capillaries of a winding course, and provided with numerous dilatation- 

 sinuses. They stand in communication with the straight lymphatic 

 capillaries. 



In some places two neighbouring superficial straight capillaries 

 anastomose with each other by means of a transverse branch provided 

 with sinuses, which belong to the peritoneal serosa. 



After what has been said about the relation of the lymphatic 

 capillaries to the lymph-canalicular system in the omentum, there 

 remains very little to be said as regards that in the centrum ten- 

 dineum. We may mention that the continuity of the endothelium 

 of the pleural lymphatic capillaries with the branched cells of the 

 lymph-canalicular system of the pleural serosa can be demonstrated 

 very easily in the centrum tendineum of rabbits and guinea-pigs. 

 We refer the reader simply to the Figs. 14, 16, and 17, on Plate IV. 



