io6 



NORMAL HISTOLOGY. 



possibly originate, and into which they finally pour their contents. They 

 arise from capillaries, have walls closely resembling in structure those of the 



Valve 



Lymph-vessel 



Lymph- 

 space 



Deeply stained 

 ground- 

 substance 



FIG. 141. Portion of central tendon of rabbit's diaphragm, treated with silver nitrate ; lymphatic vessels 

 are shown as light irregular tracts ; lymph-spaces are seen within stained ground-substance. X 120. 



veins, and are provided with many valves. 



On the other hand, the lym- 

 phatics form a system 

 which is closed, except 

 where the two chief trunks 

 open into the subclavian 

 veins, the capillaries be- 

 ginning as blind channels. 

 The most striking feature 

 of the lymph-paths, how- 

 ever, is the presence along 

 the vessels of more or 

 less conspicuous masses 

 of lymphoid tissue, the 

 lymph-nodes, often mis- 

 called lymphatic ' 'glands' ' 

 ( lympho-glandulae ) . 



Lymph-Spaces. 

 These spaces exist practi- 

 cally in all structures of 

 the body, for the most 

 part, however, as the in- 

 terfascicular clefts within 

 connective tissue. The 

 lymph-spaces are filled by a clear watery fluid, the tissue-juices, and are 

 imperfectly lined by flattened connective tissue cells. The spaces present 



FIG. 142. Perivascular lymph-spaces surrounding retinal blood- 

 vessels. X 225. 



