BY DR. KLEIN. 123 



CHAPTER VIII. 



LYMPHATIC SYSTEM. 



SECTION I. LYMPHATIC VESSELS. 



THE lymphatic vessels may be studied either by coloring 

 with nitrate of silver or by injection. As those of the serous 

 membranes are most readily demonstrated, it will be con- 

 venient to refer to them first. 



Lymphatics of the Centrum Tendineum of the 

 Diaphragm. The pleural cavity of a rabbit or guinea-pig, 

 which has just been killed, is exposed by removing the sternum, 

 care being taken to avoid opening any large bloodvessels. 

 The pleura having then been divided along the edge of the 

 costal part of the diaphragm, the cava ascendens is ligatured 

 close to the atrium, and divided between the ligature and the 

 heart. The heart and lungs are then removed from the 

 thoracic cavity. The pleural side of the centrum tendineum is 

 then carefully brushed with a camel-hair pencil, moistened with 

 serum, after which a small quantit}' of half per cent, solution 

 of nitrate of silver is poured on the diaphragm, while the 

 animal is held vertically, with its head uppermost. After five 

 minutes or so, the silver solution is poured away and replaced 

 by water, which should be changed several times. The centrum 

 tendineum may then be cut out and prepared in glycerin. Ac- 

 cording to another plan, the diaphragm is cut out immediately 

 after it has been brushed, and immersed in solution of nitrate 

 of silver. With this view the abdominal cavity is opened; the 

 ligamentum suspensorium is divided, and a ligature placed 

 round the vena portae. This vein, having been divided, the 

 whole diaphragm is cut out with the liver. In such a prepara- 

 tion clear channels are seen in the yellowish-brown ground- 

 substance, which are of various size, and of two kinds, and 

 exhibit endothelial markings. In the one kind viz., in the 

 larger vessels the endothelial elements are spindle-shaped ; 

 in the other i. e., the capillaries they are more or less sin- 

 uous. The walls of all these vessels consist exclusively of 

 endothelium. 



Before describing the arrangement of the lymphatics in the 

 centrum tendineum, it is desirable to give an account of the 

 structure of that organ. It consists of three parts, viz., pleura, 

 peritoneum, and tendon ; each serous membrane being made 



