TENDON OF THE DIAPHRAGM. 175 



Preparations 4 and 5, The central tendon 

 of the diaphragm with its serous coverings. 



The thoracic and ahdominal surfaces of the dia- 

 phragm present importantdifferences in the arrange- 

 ment of the numerous lymphatic vessels which are 

 distributed upon them. To see both properly it will 

 be necessary to sacrifice two animals. It is best to 

 use rabbits, since their central tendon is larger in 

 proportion than that of most otber mammals. 



For the preparation of either side both thoracic 

 and abdominal cavities must be freely opened, the 

 ventral attachment of the diaphragm being left in- 

 tact, so that that muscle remains stretched out. A 

 double ligature is to be put on the inferior vena cava 

 in the thorax, and the vessel cut between the two 

 threads; this is to prevent the blood in the vessel 

 from getting over the membrane. The pericardium 

 is now cut away from the upper surface of the dia- 

 phragm, and the suspensory ligament of the liver 

 from the lower. The surface which it is wished to 

 silver is then brushed pretty firmly with a camel- 

 hair pencil wetted with distilled water, after which 

 a few drops of nitrate of silver solution are allowed 

 to flow over it, or are applied with the brush. After 

 five minutes' contact the silver solution is washed 

 off by a stream of distilled water, and the central 

 tendon, including also some of the muscular fibres 

 which converge to it, is carefully removed, pinned 

 out upon a loaded cork or cake of wax, with the 

 silvered surface uppermost, and exposed to the sun- 

 light either in water or weak spirit. When dis- 

 tinctly browned it is removed from the window, 

 and pieces from different parts are cut out and 

 mounted in glycerine. 



In addition to these preparations which exhibit 

 more especially the lymphatics and cell-spaces of 

 the serous membrane, and, on the abdominal side, 

 the lymphatic clefts between the tendon bundles it 

 is useful to make another silvered preparation, un- 

 brushed, of the peritoneal suiface, a third animal 



