304 



ABSOEPTIO^. 



These accompany the deeper veins in their course. They receive the lymph from the 

 superficial vessels. 



No valvular arrangement is found in the smallest lymphatics ; but the vessels coming 

 from the primitive plexuses, as well as the large vessels, contain valves in immense num- 

 bers. These valves, being so closely set in the vessels, give to them, when filled with 

 injection, a peculiar and characteristic beaded appearance. 



FIG. ^.Superficial lym- 

 phatics of the skin of the 

 palmar surface of the 

 finger. (Sappey.) 



FIG. 84. Deep lymphatics of the skin 

 of the finger. (Sappey.) 



1, 1, deep net-work of cutaneous lymphat- 

 ics; 2, 2, 2, 2, lymphatic trunks con- 

 nected with this net- work. 



FIG. 85 Same finger, lat- 

 eral view, showing lym- 

 phatic trunks connected 

 with the superficial net- 

 work. (Sappey.) 



The course of the lymphatics is generally tolerably direct. As they pass toward the 

 great trunks by which they communicate with the venous system, they present a peculiar 

 anastomosis with the adjacent vessels, called anastomosis by bifurcation; that is, as a 

 vessel passes along with other vessels nearly parallel with it, it bifurcates, and the two 

 branches pass into the nearest vessels on either side. These anastomoses are quite fre- 

 quent, and they generally occur between vessels of equal size. In their course, the ves- 

 sels pass through the lymphatic glands, which will be described farther on. 



A notable peculiarity in the lymphatic vessels is that they vary very little in size, 

 being nearly as large at the extremities as they are near the trunk. In their course, they 

 are always much smaller than the veins and do not progressively enlarge as they pass on 

 to the great lymphatic trunks. The largest-sized vessels as they pass from the skin are 

 from -^5- to -% of an inch in diameter, and the larger vessels, in their course, have a diameter 

 of from -^ to ^ of an inch. As in the case of the smallest lymphatics in the primitive plexus, 

 the elasticity of the walls of the vessels renders their caliber greatly dependent upon the 

 pressure of fluid in their interior. Many anatomists have noticed that vessels, which are 



