AND DEVELOPMENT OF THE LIVER. 
131 
tinal cavity. The liver consists almost wholly of nuclei and diffused oily and granular 
matter, without perfect cells ; the hepatic vein is very large and distinct, and arises 
from a regular network of capillaries in the substance of the organ ; no trace of 
hepatic duct has yet made its appearance ; the primitive offset from the intestine is 
still further removed from the parenchymatous mass. The prolongations of the 
vitelline duct (anterior and posterior) have now thick walls, and their cavities are 
beginning to be formed ; they are almost shut off from the vitelline sac, the duct ap- 
pearing only as a yellow streak. 
Near the end of the eighth day there was no remarkable change in the pancreatic 
mass contained in the duodenal loop ; it manifestly had no connection by ducts with 
the intestine, but was truly a parenchyma. Close to the liver on the right of the 
pancreas there were seen two tubes ; the left one of these could be traced down for a 
considerable way, but was lost shortly before it arrived at the lower part of the pan- 
creas ; it consisted of a distinct but very fine homogeneous tunic enclosing delicate 
cells which formed a kind of epithelium. The other tube was distinct only near the 
liver, where it expanded into a pyriform sac (the gall-bladder), the cavity of which 
was distinct, lined by cells and invested by an homogeneous tunic ; from this dilata- 
tion the rudiment of the cystic duct extended only a very little way towards the intes- 
tinal cavity. Near the termination of the ascending portion of the duodenal loop, 
at the part where the remains of the original offset were still perceptible, the wall of 
the intestine was deficient, and there existed a semitransparent space leading to the 
opake contents in the interior ; but this was soon lost, and did not extend upwards to 
the ducts near the liver. At the beginning of the ninth day the gall-bladder was 
completely formed, and presented a very distinct cavity ; its duct ran down and com- 
municated with the intestine ; in the upper part of its course it was extremely 
distinct, being provided with an homogeneous tunic, and containing an abundant 
epithelium ; towards its lower part its structure is less distinct, but its course was 
clearly indicated by a transparent space, continuous with its canal, and extending 
through the intestinal wall. The hepatic duct lay by its side ; it also was more deve- 
loped above than below, and indeed could not be followed quite into the intestine 
though its future course was quite clear ; at its upper part it ran up to the liver, and 
seemed just to penetrate it, but how it terminated in this direction could not be de- 
termined ; its diameter was nearly uniform throughout, about s^th of an inch. 
Both cystic and hepatic ducts were clearly seen to join the intestine at the part 
where the primitive offset from the anterior prolongation of the vitelline duct existed ; 
this was still represented by an accumulation of opake oily matter at the spot, but 
there was no bulging of the intestinal wall. The liver consisted of nuclei, granular 
and oily matter, and perfect cells ; throughout its parenchyma there were many bright 
yellow particles of bile. 
By the first hour of the tenth day, the ducts of the gall-bladder and liver were 
perfectly formed, and communicated with the intestine at the exact spot where an 
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