LIVER. 



[ 475 ] 



LIVER. 



which are difficultly separable, and an in- 

 ternal epithelial layer. The former is most 

 distinct in the larger branches, being almost 

 absent in the terminal interlobular ducts ; 

 it contains numerous nuclei and nuclear 

 fibres. Kolatschewsky states that the bile- 

 ducts are directly continuous with the 

 cavity of the liver-cells. The epithelium 



Fig. 408. 



Magnified 200 diameters. 



Biliary capillaries from the liver of the rabbit: o, 

 biliary capillaries ; 6, liver-cells ; c, bile-ducts ; d, ca- 

 pillary blood-vessel. 



of the larger ducts is cylindrical, that of 

 the smaller of the pavement kind. In the 

 hepatic ducts, the outer coat contains scat- 

 tered muscular fibre-cells. The ducts also 

 contain small mucus-glands. The secreting 

 cells of the lobules fill up the interspaces 

 between the blood-vessels. They are very 

 transparent, of a rounded or polygonal form, 

 about 1-1000" in diameter, containing one 

 or two nuclei, with a very fine reticulum 

 and a number of granules, and a few small 

 globules of fat (fig. 160, page 238). 



Kupffer describes star-cells existing with- 

 in the liver-cells, after staining with chlo- 

 ride of gold. 



The division of the substance of the liver 

 into lobules is rather apparent than real, 

 being effected by the peculiar arrangement 

 of the vessels, the lobules having no true 

 coat or envelope. 



The connective prolongation of Glisson's 

 capsule which accompanies the vena portse 

 and its branches becomes less and less in 

 quantity as the branches become smaller, 

 and is apparently lost in the interlobular 

 spaces. It is much more abundant in 

 animals, as the pig, than in man, rendering 

 the tabular arrangement much more dis- 

 tinct. But, after washing away the liver- 

 cells with a hair-pencil, from a thin section, 

 a very delicate network, consisting of a 

 homogeneous membrane with minute nu- 



clei, remains, in the meshes of which the 

 liver-cells are placed. 



The branches of the hepatic artery are 

 distributed to the portal vessels, the hepatic 

 ducts, Glisson's capsule with its prolonga- 

 tions, and the peritoneal coat. They are 

 often elegantly tortuous. 



Among the more common morbid states 

 of the liver may be mentioned : that called 

 cirrhosis, in which the connective tissue is 

 excessively developed and mixed with a 

 large number of fibro-plastic corpuscles, 

 producing an atrophied state of the epithe- 

 lial structure; the amyloid degeneration, 

 which commences between the inter- and 

 intra-lobular portions, in the branches of 

 the hepatic artery ; an increase in the 

 amount of fatty matter in the cells (fig. 160, 

 page 238) ; and the presence in these also 

 of granules of cholepyrrine, rarely with 

 crystals of cholesterine and bilifulvine. 



The examination of the arrangement of 

 the blood-vessels is best made in a liver 

 which has been injected with two kinds of 

 injection, as yellow (chromate of lead) and 

 red (vermilion), or red and white (carbonate 

 of lead) the yellow or white being injected 

 into the hepatic vein. As the injection is 

 being proceeded with, the surface of the 

 liver should be examined with a lens to 

 ascertain whether the intralobular veins are 

 well filled, and the injection has reached 

 the capillaries; the red injection should 

 then be thrown into the portal vein until 

 it is filled. The general vascular arrange- 

 ment is best observed in an injection in 

 which the capillaries themselves are not 

 filled, but only the smaller portal and he- 

 patic branches. 



To examine the ducts as to their course 

 and termination, the portal vein should 

 previously be injected. If this be not done, 

 the injection easily bursts through the walls 

 of the terminal ducts, and escapes into the 

 intralobular plexus ; and thus the appear- 

 ance of a plexus of vessels prolonged from 

 the terminal ducts is produced. The fine 

 ferridcyanide cold injection should be used. 



The structure of the hepatic cells is easily 

 seen on scraping the surface of a section of 

 the liver, and placing the portion thus ob- 

 tained between two pieces of glass as usual. 



The minute structure of the liver is best 

 seen in sections of portions which have 

 been hardened in chromic acid or spirit, 

 and stained with logwood. In these, the 

 cut orifices of the biliary capillaries are 

 sometimes seen, between the liver-cells. 



