82 The Microscopic Structure ere tre 
proceed from this plexus, some of which join small hepatic ducts, 
and others the plexus formed by the ducts of the hepatic glands. 
The extensive plexus of lymphatics in the “capsule of the hepatic 
veins” take their origin from the “biliary tubules” surrounding 
the intra-lobular hepatic ves; they also communicate freely with 
the ducts of the hepatic glands. In the capsule on the surface of 
the liver, the finer lymphatics, after having arisen from the “ biliary 
tubules,” anastomose with each other, and then joi the network of 
large meshes already described. 
The finest lymphatic vessels present that nodose appearance so 
peculiar to this system of vessels, of the larger ones. ‘The nodosi- 
ties, of course, are caused by constrictions in the walls of the vessels ; 
they correspond to the place where the valves, with which these 
vessels are provided, are situated. These valves, in the finer lym- 
phatics, can easily be seen under the microscope. 
The existing communication between the lymphatics and hepatic 
ducts will be further discussed hereafter. 
System of Plexus, formed by the Ducts of the Hepatic Glands. 
The different localities in which this singular system of small 
glands with the plexus, formed by their ducts, is found in the 
human liver have already been mentioned; it only remains to 
describe the peculiar character of its component elements, and the 
relation of the latter to the ducts, lymphatics, and blood-vessels. 
The small glands, attached to those ducts, which form the plexuses, 
vary considerably in size and form. Many of them join the plexus 
of ducts in the form of a simple follicle, while others—perhaps the 
majority—first combine with each other to form a small racemose 
gland, before joining the plexus (Fig. 3). The diameter of the 
follicles ranges from yo'5p to to{oo of an inch. Their duct or neck 
is very fine, usually 3955 of an inch in diameter, but sometimes it 
is almost as wide as the little gland itself; occasionally the latter 
has the mere form of a pouch or dilatation. Many of these follicles 
are sessile, especially the smaller; and often are only so large as 
to be lined by five or six epithelial cells. Sometimes the duct of 
the follicle assumes the form of a pedicle before joining the plexus ; 
in such cases the vessel of the plexus which they join is usually 
very fine and the follicles are then set far apart. The small race- 
mose glands, formed by the union of a number of follicles, also differ 
among themselves ; especially in the size of theirmain duct, through 
which they are connected with the ducts of the plexus. Usually 
the size of this corresponds with the number of follicles of which 
the racemose gland is composed; but in many of them the main 
duct is comparatively wide, and the follicles are almost sessile upon 
it, or join it by very short ducts. 
