ae eee of the Human Liver. 87 
microscopic examination? It certainly ought to be the same as in 
the former case. Another explanation, however, might be offered 
to explain the phenomenon; as, for instance, the possibility of a 
rupture of the finer branches of the hepatic duct and of the capil- 
laries of the blood-vessels, which would afford an opportunity to the 
coloured material to pass from one set of vessels into the other. 
Although inclined to deny the probability, I admit the possibility 
of such an occurrence in one or even in a few instances. ‘This 
explanation of the phenomenon, however unsatisfactory as it already 
is in itself, loses every appearance of probability when we meet by 
a subsequent examination with the most regular capillary network, 
of the same colour as the material which was injected into the he- 
patic duct, and without exception, in scores of instances ; or, in other 
words, in every experiment performed. With such facts before us, 
we can no longer doubt the continuity of such capillary network 
with the finest branches of the hepatic duct, into which the coloured 
material was injected. Again, if we observe the continuity of the 
network with the finest branches of the hepatic duct, as represented 
in Fig. 1, ¢ and f, the evidences are still stronger, for certainly no 
anatomist who is familiar with the diameters and characters of the 
branches of the hepatic duct and those of the blood-vessels would 
ever confound the former with the latter. 
There are still other proofs, strong enough to convince even the 
most sceptical or rather prejudiced mind; for instance: A liver is 
taken, and its vessels and ducts carefully injected—in the manner as 
will be described in one part of this treatise—with different colours ; 
for example, Prussian blue into the hepatic duct, yellow into the 
hepatic artery, red into the portal vein, and white into the hepatic 
veins. If now, by examining fine sections of such a specimen of 
liver we recognize the different individual vessels by their peculiar 
characters as well as by their respective colours, injected into their 
parent trunks, and also by the relative position they occupy towards 
each other, and then directly trace the finest branches of each to 
a network of capillaries of its own colour, what further proofs can 
be expected of the correctness of my statements? In such a case 
the branches of the hepatic duct, which were injected with the 
Prussian blue, are observed to terminate in a blue network of capil- 
laries, while those of the hepatic artery and portal vem are seen to 
terminate in another of yellow and red, one or the other of which 
usually predominates. 
Frequently we find either one or the other network more or less 
injected. The cause of this is very obvious. If, for example, the 
capillaries of the blood-vessels are filled with the injecting material 
sooner than those of the hepatic duct, the former, being already dis- 
tended, press upon the latter—with which they interlace,—and thus 
prevent the entrance of the material which was injected into the 
