132 
DR. C. H. JONES ON THE STRUCTURE 
opake mass still indicated the situation of the original offset from the intestine ; the 
gall-bladder was quite visible to the naked eye, full of green bile, which was made, I 
think, by pressure to flow into the intestine. The pancreatic mass had now sepa- 
rated into two portions, skirting the contiguous margins of the duodenal loop ; a 
rudiment also of its duct had begun to be developed ; it appeared as a solid cylin- 
drical tract of nuclei, continuous with, a canal which entered the intestine together 
with the ducts from the liver. By the end of this day two pancreatic ducts were 
distinctly developed, one joining the hepatic just before its termination, the other 
entering the intestine together with the hepatic and cystic. I endeavoured to 
trace the further development of the hepatic duct with its branches in the substance 
of the liver, but without much success ; it appeared to me however that they were 
first formed as solid tracts of nuclei, bearing some resemblance to the terminal ducts 
in the mature condition. The parenchyma of the liver now contained numerous par- 
ticles of bright yellow or green bile ; bile also filled the gall-bladder, and had flowed 
into the intestine. 
The observations now related, warrant I think, the following conclusions : — 
I. That the liver exists at one time as a parenchymatous mass, independent of any 
offset from the alimentary canal. 
II. That though the first indications of the hepatic duct proceed from the intes- 
tine, yet these disappear, and are replaced by a separate and independent formation, 
which gradually developes itself further, both downwards tojoin the intestinal canal, 
and in the substance of the liver itself. 
III. Biliary matter is formed in the hepatic parenchyma before its communication 
with the duodenum is freely established. 
The following propositions may serve as a resume of the principal conclusions to 
which we have been led during our survey of the various forms of hepatic structure. 
The liver in all vertebrate animals may be regarded as consisting of a secreting 
parenchyma and excretory ducts. 
The size of the excretory apparatus bears only a small proportion to that of the 
secretory. 
These two portions of the liver are not continuous with each other, but disposed 
simply in a relation of juxtaposition. 
The action of the liver seems to consist in the transmission of the bile as it is 
formed from cell to cell, till it arrives in the neighbourhood of the excretory ducts 
by which it is absorbed. This action is probably slow, and very liable to be inter- 
fered with, contrasting remarkably with that of the kidney, where a particular appa- 
ratus is added to ensure completeness and rapidity of action. 
The secretion of the hepatic cells is very liable to be retained within the gland, 
either in the cells or in a free state. 
This circumstance, as well as its structural peculiarities, seem to point out the liver 
as approximating to the class of ductless glands. 
