AND FUNCTION OF THE LIVER. 
3 
this agent, when added directly to a portion of parenchyma, produced no marked 
effect on the cells, rendering them only somewhat more granular, but coagulated a 
considerable quantity of the free interposed material. 
Having described these two results, which, though quite capable, as I conceive, of 
being otherwise interpreted, appear to support the opinion of there being a lobular 
biliary plexus, either containing and enclosing the cells in its passages, or interposing 
its tubes between them, I now proceed to detail those observations which I have 
recently made, and which after candid consideration do still confirm me in the 
opinions I formerly expressed, and also throw some light on the mode in which the 
efferent mechanism may be conceived to perform its function. 
The class of Fishes I have found, as before, most easy of examination, and most 
productive of results, and I would ask inquirers into the subject to direct their 
attention carefully to these examples. My later dissections have confirmed entirely 
the description given in my last paper; they show the ducts running a long course 
with comparatively little branching through the parenchyma, encrusted by it on 
every side, and terminating without forming any such connection with it as to 
envelope and surround it. Often the ultimate branches appear as tracts of finely 
granulous or amorphous matter, in which, when it is broken up, delicate nuclei are 
discerned : this is perhaps the most common condition, but there are two others which 
I have most unquestionably observed, and which quoad the physiological action of the 
parts are of great interest. In one of these, the least common, the nuclei are not 
obscured by the granulous matter, but are distinctly visible, as I figured them in my 
last paper from the liver of the Perch ; they seem to constitute the chief part of the 
wall of the ductule, and lie close together in a scanty amount of granulous basis 
substance. This condition, unusual in Fishes, is ordinary in Mammalia ; of its im- 
port we shall subsequently attempt to give some interpretation. In the other condi- 
tion, the ducts, not only the terminal, but even the smaller trunks, are Jilled with a 
pellucid opaline material, in which are imbedded vesicles containing a fluid of the 
same aspect ; often the vesicles are exceedingly numerous, and seem to replace the 
opaline material ; it may indeed be said that the two exist in inverse ratio, and that the 
one is developed from the other. It seems most probable that the fluid in the interior 
of the vesicles is bile, and that by their dissolution it is set free in the efferent passage. 
A very frequent appearance is, that in the interior of ducts the outlines of vesicles 
are discerned more or less distinctly in various parts amid translucent free material. 
The size of the vesicles varies a good deal, from 3-^^rd of an inch to T(fo”oth of an 
inch ; they seem of exceeding delicacy, but resist sufficiently to alter each other’s 
shape by mutual pressure, and to float about in the water for a short time after they 
have escaped from the duct. I have called them vesicles, as they do not commonly 
appear to contain nuclei ; but in one instance I found that nuclei did exist in their 
interior, so that they may sometimes no doubt attain the rank of cells. 
An important point to be noticed with regard to the ultimate and penultimate 
ducts is, that they appear to be Jilled with their epithelium ; the central passage must 
B 2 
