AND FUNCTION OF THE LIVER. 
19 
It is perfectly clear that in neither of these cases it interferes in the least with the 
healthy discharge of the function, and we may learn therefore that excess alone of oil in 
any part does not constitute “ fatty degeneration.” The epithelial particles of the gall- 
bladder in these cases are loaded with oily molecules ; they easily break up, and give 
exit to it very soon after death. No such oily accumulation occurs, at least necessarily, 
in the parenchymal cells; a further confirmation of the opinion above stated, that 
these cells are not, quoad position, a continuation of the epithelium of the ducts. 
In some Human livers I have recently observed the ultimate ducts in a very satis- 
factory manner, and believe, on the whole, that the mode I am about to mention is 
the best for obtaining a view of their course and relations. A very thin section of 
the liver must be made at one or two lines depth from the surface ; this is to be treated 
with acetic acid, and moderately compressed ; if the liver be tolerably free from oily 
matter it will now become much more transparent, and on careful examination of the 
portal canals, spaces and fissures, some ducts will be found, and their course may be 
traced. It is manifest that in this way of proceeding the ducts are examined in situ ; 
and if the observer have previously acquainted himself with their appearance by dis- 
secting them out as they lie in the Glissonian sheaths, he will have no difficulty in 
recognizing them and following them, though he may have much difficulty in con- 
vincing himself of their actual mode of termination. Their termination by distinctly 
closed extremities I have certainly observed, as well as the slight amount of ramifica- 
tion they present, and the little intimate relation they appear to hold to the walls of 
parenchyma between which they run. In many fissures not a trace of them can be 
seen ; and in those where they exist it is manifestly impossible that they can come into 
relation with any more than a very small portion of the parenchyma. How then, if 
all the cells secrete bile, could this make its way into the ducts ? The ducts as they 
run in the fissures and canals are in the closest relation to the portal vein branch, 
and surrounded by the terminal plexus of the hepatic artery ; so delicate, so truly 
homogeneous is the tunic of the vein, that it seems to me scarce possible but that the 
ducts in the smallest portal canal and fissures should be bathed in plasma exuding 
from it ; from the plexus of slender capillaries, in which the hepatic arterioles termi- 
nate, they must also receive part of their supply ; and lastly, when the secretion of the 
marginal cells of the lobules is abundant, or when the liver, as in fish, is a mass of 
oil, they must be bathed in this fluid. 
In considering what is probably the function of the parenchyma, i. e. of the chief 
mass of the liver, vve may with advantage enumerate seriatim, the chief points which 
may be regarded as pretty well ascertained respecting it. (1.) It consists, at least in 
Mammalia, of cells, which as long as they retain their active power exhibit nuclei; 
these nuclei are imbedded in a soft homogeneous granulous substance which very 
commonly contains oil-drops, and sometimes biliary molecules, or is tinted with 
bilious fluid ; an envelope much more distinct than in most other glandular cells 
surrounds the whole particle, and seems to denote a certain amount of permanency 
D 2 
