262 STRUCTURE OF THE LIVER. 



mixed with circularly-disposed smooth muscular fibres (fig. 195). Capillaries are supplied to 

 the wall, which is lined by a single layer of columnar epithelium. A sub-mucosa occurs only 

 in the largest bile-ducts, and in the gall-bladder. Smooth muscular fibres, arranged in single 



bundles, occur in the largest ducts, and as longitudinal and 



circular layers in the gall-bladder, whose mucous membrane 



is provided with numerous folds and depressions. The 



Circular " _25^$W^^$fc:- epithelium lining the gall-bladder is cylindrical, with a dis- 



fibres. ^^ySb* tinct clear disc, and between these cells are goblet-cells. 



Small branched tubular mucous glands occur in the larger 

 bile-ducts and in the gall-bladder. 



Vasa aberrantia are isolated bile-ducts which occur on 

 Cylindrical ^J]JJi& *^ ie sul 'f ace f the liver, but have no relation to any system 



epithelium. ^JBB@*{ /$S*$maffi of liver-lobules. They occur at the sharp margin of the 



liver, in the region of the inferior vena cava, of the gall- 

 bladder, and of the parts near the portal fissure. It seems 

 that the liver-lobules to which they originally belonged 

 have atrophied and disappeared (ZuckerTcandl and Toldt). 

 Fig. 195. 5. The lymphatics begin as pcrica'pillary tubes around 



Interlobular bile-duct (human), the capillaries within the lobules, emerge from the lobule, 



and run within the wall of the branches of the hepatic and 

 portal veins, and afterwards surround the venous trunks, thus forming the interlobular lym- 

 phatics. These unite to form larger trunks, which leave the liver partly at the portal fissure, 

 partly along with the hepatic veins, and partly at different points on the surface of the organ. 

 There is a narrow superficial meshwork of lymphatics under the peritoneum sub -peritoneal 

 which communicate with the thoracic lymphatics through the triangular ligament and suspen- 

 sorium, while on the under surface they communicate with the lymphatics of the interlobular 

 connective-tissue. 



6. The nerves consist partly of medullated and partly of non-medullated fibres from branches 

 of the sympathetic and left vagus to the hepatic plexus. They accompany the branches of the 

 hepatic artery, and ganglia occur on their branches within the liver. Some of the nerve-fibres 

 are vaso-motor in function, and, according to Pfluger, other nerve-fibres terminate directly in 

 connection with liver-cells. [MacCallum describes an interlobular plexus of non-medullated 

 fibres in man and menobranchus, from which a peri-vascular and intercellular plexus proceeds. 

 From the latter fibrils pass to terminate within the cells near the nucleus.] 



Pathological. The connective-tissue between the lobules may undergo great increase in 

 amount, especially in alcohol- and gin-drinkers, and thus the substance of the lobules may be 

 greatly compressed, owing to the cicatricial contraction of the newly-formed connective-tissue 

 (cirrhosis of the liver). In such interlobular connective-tissue, newly-formed bile-ducts are 

 found. 



Ligature of the ductus choledochus [causes enlargement of the spleen (rabbit), and a 

 diminution in the number of the blood-corpuscles], and, after a time, interstitial inflammation 

 of the liver. In rabbits and guinea-pigs the liver-parenchyma disappears, and its place is 

 taken by newly-formed connective-tissue and bile-ducts (Charcot and Gombault). In all these 

 cases of interstitial inflammation, there is proliferation of the epithelium of the bile-ducts. 



[Regeneration of the Liver. Tizzoni finds that there may be partial regeneration and new 

 formation of liver-lobules in the dog, the process being the same as that which occurs in the 

 embryonic development of the organ, i.e., the growth of solid cylinders of liver-cells, formed by 

 the pre-existing liver-cells, which penetrate into the connective-tissue uniting the edges of the 

 wound. These cells ultimately differentiate into hepatic cells and bile-ducts. Other observers 

 attribute the new formation to outgrowths of the epithelial cells of the bile-cells.] 



174. CHEMICAL COMPOSITION OF THE LIVER-CELLS. (1) Proteids. 



The fresh, soft, parenchyma of the liver is alkaline in reaction; after death, 

 coagulation occurs, the cell-contents appear turbid, the tissue becomes friable, and 

 gradually an acid reaction is developed. This process closely resembles what occurs 

 in muscle, and is due to the coagulation of a myosin-like body, which is soluble 

 during life, but after death undergoes spontaneous coagulation (Plosz). The liver 

 contains other proteids; one coagulating at 45 C, another at 70 C, and one 

 which is slightly soluble in dilute acids and alkalies. The nuclei contain nuclein. 

 The connective-tissue yields gelatin. 



(2) Glycogen or Animal Starch 1*2 to 2*6 per cent. is a true carbohydrate 

 most closely related to inulin, soluble in water, but diffuses with difficulty, and has 

 the formula 6(C 6 H 10 O 5 ) + H 2 0. It is stored up in the liver-cells in amorphous 

 granules around the nuclei (fig. 194, 2), but is not uniformly distributed in all 



