ARRANGExMENT OF THE BILIARY DUCTS. 
385 
smaller canals, but they often change the side upon which they lie. Usually, one 
branch of the duct and artery accompanies the portal vein, but not unfrequently there 
are two or more branches of these vessels around the vein. 
Anastomosis of the ducts near the trunk from which they come oJf'.—T\\Q anasto- 
mosis between the larger ducts and of the larger branches of the interlobular ducts 
with each other in the human liver is pretty numerous, but they are confined to the 
trunks near their origin. In some animals the branches resulting from the division 
of the small ducts communicate with each other at a distance from the parent trunk at 
the margin of the lobule. These communications may be very few in number, or so 
numerous as to form a network upon the surface of the lobule. 
The anastomoses of different interlobular ducts with each other round the lobules, 
according to my observations, are very rare ; and out of numerous injections, I have 
been able to satisfy myself of its actual occurrence only in one instance. 
Kiernan observed, that if the left hepatic duct were injected with size or mercury, 
the injection returned by the right duct. It seems not improbable that this may 
have resulted from the numerous communications between these ducts in the trans- 
verse fissure of the liver, rather than from the union of interlobular branches. Not 
only do the right and left hepatic ducts anastomose by the intervention of small 
tortuous branches in the transverse fissure of the human liver, as E. H. Weber many 
years ago demonstrated, but the branches which come off from these trunks are con- 
nected by smaller ones which arise not far from the point at which they are given 
off. Many of my preparations show a most complete and intimate network at a short 
distance from the parent trunks in the transverse fissure, and to a less extent in the 
portal canals. This curious and beautiful network is shown in Plate XIII. figs. 2, 
3 & 5. The smallest of these branches seem to have no fibrous coat, and in the larger 
ones this is much thinner than in the ordinary ducts. In the portal canals these 
anastomosing branches connected with the ducts are much less numerous, and some 
of the small communicating branches lie in the thick coats of the ducts, Plate XIII. 
fig. 6 a. 
In the foetus the communications are less numerous and the branches less tortuous, 
but they are to be shown more readily than in the adult, in consequence of their 
being surrounded by a much less quantity of areolar tissue. In the dog and in the 
calf I have seen similar communications (Plate XIV. fig. 13 a), but they are less 
numerous than in the human subject. 
In the instances above referred to, an irregular network of ducts, more or less 
extensive, is to be demonstrated near the trunks, but the arrangement is not constant 
in all animals, nor, so far as I can ascertain, are these communications numerous 
enough to entitle them to the name of interlobular plexus or network. I have not 
been able to demonstrate such a network, although I am not prepared to say that it 
is absent, in the pig, seal, rabbit, horse, cat and monkey. If these communications 
exist in these animals, they can only be present in a limited extent. 
