io6 PRACTICAL HISTOLOGY. 



on the peritoneal surface of the centrum tendineum of the 

 guinea-pig and rabbit, in the chronic peritonitis induced by 

 tubercle-inoculation. (Klein.} 



Stomata essentially similar to these may be demon- 

 strated by the above process in other situations, such as 

 the pleura and the surface of the centrum tendineum. 

 Their existence was first made known by Recklinghausen 

 in the latter situation. 



170. Lymphatics of Diaphragm. Examine a pre- 

 paration made as follows : 



Kill a rabbit a young one is to be preferred and remove the 

 anterior wall of the chest. Ligature the inferior vena cava near its 

 cardiac end ; separate the pleurae from the diaphragm, and remove the 

 heart and lungs. Remove the investing serous epithelium by pencilling 

 the upper surface of the diaphragm with a camel-hair brush dipped in 

 the serum found in the chest. Wash the pencilled surface with dis- 

 tilled water ; pour over it a half per cent nitrate of silver solution ; 

 allow to remain for three or four minutes, and then wash thoroughly 

 with distilled water. The diaphragm with its osseous and cartilaginous 

 attachments is then cut out and placed in a vessel with distilled water, 

 until the silvered surface becomes of a brownish colour. The centrum 

 tendineum may then be cut into pieces and mounted in glycerine. The 

 lymphatics near the under surface of the diaphragm may be demon- 

 strated in a similar manner. 



(L.) The lymphatics form an anastomosing system of 

 irregular channels of various sizes. The silvered outlines 

 of their epithelial wall are evident. Alternate dilatations 

 and constrictions are often seen on the smaller vessels. 

 The appearance resembles a series of Florence flasks set 

 one above another. There are no valves at the swellings, 

 such as are found in large lymphatics. 



(H.) In the smallest lymphatics the epithelial outlines 

 are more sinuous than in the larger vessels, and in the 

 latter the outlines of the cells are more or less parallel with 

 the long axis of the vessel. In favourable specimens, the 

 smallest lymphatics may be seen opening into connective 

 tissue spaces, as described by Recklinghausen. This mode 

 of origin may be beautifully seen in the superficial lymph- 

 atics of the intestinal villi ( 193). 



The smallest lymphatics consist entirely of a simple 



