XVIIl] LYMPHATIC SYSTEM 145 



Superficial to the tendon bundles the epithelium of the 

 peritoneum consisting of flat polygonal cells; these are larger 

 over the tendinous bundles than over the intervening spaces. 

 Stomata similar to those of 2 may be seen, situated over 

 and communicating with the inter-tendinous spaces. Pseudo- 

 stomata, irregular patches of staining substance at the junctions 

 of the cells, are frequent. 



4. In a guinea-pig or rabbit, brush firmly the pleural surface 

 of the diaphragm with a camel-hair brush to remove the surface 

 epithelium and treat with nitrate of silver. Mount with the 

 pleural surface uppermost. Note 



The small lymphatic vessels, running a little above the 

 tendinous bundles and lined with somewhat irregular spindle- 

 shaped epithelium. In places the curved outline of a valve may 

 be seen. 



The superficial lymphatic capillaries with their characteristic 

 sinuous epithelium continuous with the lymphatic capillaries of 

 the inter-tendinous spaces. 



The origin of the lymphatics. This is best seen in specimens 

 deeply stained with nitrate of silver, so as to produce the so- 

 called negative image. Note the clear branched spaces, whose 

 sinuous outline resembles that of an epithelium cell of a lymphatic 

 capillary. The clear spaces, cavities containing unstained con- 

 nective-tissue corpuscles, stand out in strong contrast with the 

 surrounding stained matrix. It may be seen that these spaces 

 here and there apparently form the beginning of a lymphatic 

 capillary. 



5. Sections of a small lymphatic gland, including 

 the hilus (one of the upper cervical glands of cat or 

 dog ; ammonium bichromate 2 to 5 p.c. ; cut frozen). 

 Stain with hsematoxylin and eosin and mount in 

 balsam. 



a. Observe under a low power 

 The connective-tissue of the capsule surrounding 

 the gland and sending in 



L. 10 



