THE STRUCTURE OF THE LIVER. 



309 



polygonal mesh about each liver-cell (Fig. 117, 3 ). The ducts almost always lie 

 midway between the surfaces of two adjacent liver-cells (Fig. 116, II, a) as true 

 intercellular passages or secretory spaces. When the cells fall apart in the process 

 of maceration, they retain only semicircular depressions. The finest ducts of the 

 bile-capillaries have been observed to penetrate the interior of the liver-cells and 

 to communicate here with roun 



-s 



to communicate here with round, secretory vacuoles containing bile (Fig 117 7) 



along the edges of the rows of liver-cells, while the 



As the blood-capillaries run e rows o ver-ces, we te 



biliary ducts run along the surfaces of the cells, both systems of ducts are always 

 at a definite distance from one another (Fig. 118). " 



In human beings individual bile-ducts sometimes run also along the edges of 

 the cells, so that they must then act as intercellular ducts of 3 or 4 cells This 

 arrangement is said to predominate in the embryonal liver. In addition to in- 

 jection, the capillaries can be made visible by staining by Golgi's method 



V.i 



V. 



FIG. 116. I. Diagrammatic Representation of an Hepatic Lobule: V. i., V. i, interlobular veins; V. c, central vein; 

 c, capillary between the two; V. s, sublobular vein; V. v, vascular vein; A A, branches of the hepatic artery, 

 approaching the capsule of Glisson and the larger blood-vessels at r r, and forming the vascular vein further 

 on, entering the capillaries of the interlobular veins at i i; g, branches of the bile-duct, dividing at x x between 

 the liver-cells; d d, situation of liver-cells in the capillary network. II. Isolated liver-cells, at c lying upon 

 a capillary blood-vessel and forming a fine bile-duct at a. 



Within the peripheral, cortical portion of the lobule the ducts, without walls, 

 increase in size by anastomosis of neighboring ducts. They then leave the acinus, 

 in order, from this point, uniting between the lobules (Fig. 116, g) with adja- 

 cent ducts, to form larger bile-ducts, with numerous anastomoses. These, in com- 

 pany with the branches of the hepatic artery and the portal vein, finally leave 

 the transverse fissure of the liver as a collecting duct, the hepatic duct. The finer 

 interlobular bile-ducts possess a structureless membrana propria with low epithe- 

 lium. The larger (Fig. 119) exhibit a double membrane constituted of connective 

 tissue and elastic fibers, the internal layer being c-sjuvially supplied with blood- 

 capillaries and bearing a single layer of cylindrical epithelium. Only in tin- largest 

 branches, and in the gall-bladder, does this internal layer Kv<>me an independent 

 mucous membrane, with submucosa. Unstriped muscle-fibers are found in isolated 



