ANATOMY OF THE LACTEAL AND LYMPHATIC VESSELS. 283 



that silver nitrate stains the solid parts of tissues and the borders of the en- 

 dothelial cells, and that non-nucleated areas which do not present any stain- 

 ing are necessarily open. In preparations of the lymphatics, the solution of 

 silver is seen staining the tissues and the borders of the cells lining the ves- 

 sels ; but there are areas between these cells where no staining is observed 

 and in which no nuclei are brought out by staining with carmine. 



Lymphatic Glands. In the course of the lymphatic vessels, are small, 

 lenticular bodies, called lymphatic glands. The number of these is very 

 great, although it is estimated with difficulty, from the fact that many of 

 them are very small and are 

 consequently liable to escape 

 observation. It may be stated 

 as an approximation that there 

 are six or seven hundred lym- 

 phatic glands in the body. 

 Their size and form are also 

 very variable within the lim- 

 its of health. They generally 

 are flattened and lenticular, 

 some as large as a bean and 

 others as small as a small pea 

 or even a pin's-head. They 

 are arranged in two sets ; one 

 superficial and corresponding 

 with the superficial lymphatic 

 vessels, and a deep set, corre- 

 sponding with the deep ves- 

 sels. The superficial glands 

 are most abundant in the 

 folds at the flexures of the 

 great joints and about the 

 great vessels of the head and 

 neck. The deep-seated glands 

 are most abundant around the 

 vessels coming from the great 

 glandular viscera. A distinct 

 set of large glands is found 



connected with the lymphatic vessels between the folds of the mesentery. 

 These are known as the mesenteric glands. All of the lymphatic vessels pass 

 through glands before they empty into the great lymphatic trunks, and most 

 of them pass through several glands in their course. 



The perfect, healthy glands are of a grayish-white or reddish color, of 

 about the consistence of the liver, presenting a hilum where the larger blood- 

 vessels enter and the efferent vessels emerge, and are covered, except at the 

 hilum, with a delicate membrane composed of inelastic fibres, a few elastic 

 fibres and non-striated muscular fibres. Their exterior is somewhat tuber- 



FIG. ^.Lymphatics and lymphatic glands (Sappey). 

 1, upper extremity of the thoracic duct, passing behind the 

 internal jugular vein ; 2, opening of the thoracic duct 

 into the internal jugular and left subclavian vein. The 

 lymphatic glands are seen in the course of the vessels. 



