derived mainly from the ramifications of those nerves that belong to 
the portal system, and to a much smaller extent from branches that 
follow the hepatic arteries and the biliary ducts. 
The distribution of the nerves following the portal veins takes 
place in a two-fold manner. (1) Nerves accompany all branches of 
the inter-lobular portal system, usually in the form of a few scattered 
nerve fibres following the course of the vessel; though nearer to the 
transverse fissure large bundles may be seen (fig. 2), with as many 
as a dozen or more filaments to the bundle. On both smaller and 
larger inter-lobular portal veins (fig. 11), there are here and there 
short branches given off, that shortly end upon the outer wall of 
the vessel, either in single knob-endings, or collections of endings 
of some-what peculiar form (fig. 11), also, and more rarely, in com- 
mon with all the inter-lobular nerves, fibres come off from the 
main stems and penetrate between the liver cells for considerable 
distances, branching and anastomosing as they go. Figure 8 is from 
a plexus arising from a central portal vein, fig. 9 from a fibre that 
originally arose from an inter-lobular nerve, and after a very long 
course as a single fibre, split up and formed the picture as drawn. 
The fibres following the central portal vein are equally distinct 
as those accompanying the inter-lobular ones; they often surround a 
cross section of the vein with numerous filaments, and distinct knob- 
endings upon and in the immediate vicinity of the sheaths of the vein, 
are frequently to be met with; and from these portal nerves and 
their branchings, come apparently the largest supply to the glandular 
structures. A nerve filament may leave the parent stem adjacent to 
the vein, and wander off singly and indefinitely through the tissues 
of the lobule, terminating usually with a knob-ending; or it may split 
up between the liver cells and form a complete plexus, upon and 
around them, following the lines of the biliary canaliculi in large part, 
but not exclusively; and showing here and there terminal endings, 
commonly in single knob shapes, or more rarely arborizations. A few 
forked endings have been met with, half surrounding cross sections 
of the portal capillaries within the lobules, but in such a position as 
to render it doubtful whether they are directly upon the capillary 
wall, or between it and the liver cells. However, the function of the 
knob-endings upon the larger portal vessels cannot for a moment be 
questioned, which is solely to act upon its unstriped muscular fibres 
and produce contractions and relaxations of the vessels. 
The second division, the nerves distributed to the arterial rami- 
fications, vary little from the ordinary type of vascular nerves in other 
