74 The Microscopic Structure _—_[yonthls Microsecpicn 
from their parent trunks of the portal vein, unlike the arteries, they 
remain not at the internal surface of the capsule to subdivide and 
form anastomoses, but penetrate at once into the tissue of the 
capsule. Here, from their subdivisions, an extensive venous plexus 
is formed, from which, ultimately, all those smaller branches arise 
that accompany the arterial branches above described. 
The hepatic ducts, resulting from the various subdivisions of the 
main trunk—always corresponding with those of the portal vein 
and hepatic artery—give origin to a number of small branches, the 
largest of which accompany the inter-lobular veins and arteries, 
while the smaller ones proceed directly to the parenchyma. All 
branches of the hepatic ducts—with the exception of those which 
enter the parenchyma, commonly called “lobular,” and also the 
finer “ inter-lobular ”—are joined by numerous fine communicating 
branches from that plexus formed by the ducts of the hepatic glands. 
The nerves within the capsule of the portal vessels are numer- 
ous: they form a complicated plexus, principally around the artery. 
The diameter of the finest branches, I observed, was 55 of an 
inch ; accompanying an artery of s}5 of an inch; they still formed 
a plexus. The investigation of the termination of the nerves would 
necessarily involve a great deal of time. Not being able to devote 
my attention to the subject for the present, I am obliged to postpone 
this part to a future period. 
The plexus formed by the ducts of the hepatic glands in the 
capsule of the portal vessels is very extensive. It communicates— 
as already noticed—by numerous branches with the hepatic ducts, 
and it is also joined by many branches of the plexus of lymphatic 
vessels. 
The lymphatic vessels within this capsule form a plexus which 
communicates by small branches with the small hepatic ducts and 
the plexus of the glands; the rest joing each other, enlarge as 
they proceed until they take their exit from the liver. 
2. Within the Capsule of the Hepatic Veins.—The branches of 
the hepatic artery which proceed to the capsule of the hepatic veins 
divide and anastomose freely with each other; their diameter is 
about from ;}5 to 74, of an inch. The anastomoses thus formed 
give origin to smaller branches of about 3}; of an inch diameter, 
which, by anastomosing with the former, render the meshes of the 
network considerably smaller and more complicated. Finally, still 
smaller branches arise from this network, a number of which are 
seen to terminate in the capillaries of the adjacent parenchyma, 
while the rest proceed to the fibrous coat of the hepatic veins within 
which they form a plexus with large meshes. 
The portal vein sends a few short branches from which smaller 
ones arise, which, in their distribution, correspond to those of the 
artery. 
