184 



MANUAL OF HISTOLOGY. 



sulce of the liver. Their form is irregularly polyhedral, and 

 they usually measure about 4x1 mm. At their bases they 

 are attached to short twigs of the hepatic vein, which have a 

 thickness of from 0.08 0.06 mm., and traverse the lobules in 

 the axes of their long diameters. As the hepatic vein ascends 

 through the lobule, it gives off innumerable capillary branches, 

 almost at right angles to its course. The latter pursue their 

 way to the periphery of the lobule, and hence have a radial 

 direction. These capillaries further subdivide within the lob- 

 ules, and are united to each other by transverse branches, 

 forming a network with small meshes. At the periphery the 



capillaries join the rami- 

 fications of the portal 

 vein. The latter divides 

 within the liver into nu- 

 merous branches, which 

 again subdivide at the 

 surfaces of the lobules. 

 Their ultimate ramifica- 

 tions form the boundary 

 lines between adjoining 

 hepatic lobules, and it- 

 is for this reason that 

 they have been called 

 interlobular veins. 1 For 

 a similar reason the 

 branches of the hepatic vein, which traverse the centres of 

 the lobules, have been called intralobular ' or central veins 2 

 (Fig. 80). 



The interlobular veins are contained within interlobular or 

 intermediate (Hering) canals ; these are easily demonstrable in 

 the hog's liver. In this animal the adjoining edges of three 

 or four hepatic lobules combine to form a canal which con- 

 tains the interlobular vessels. The latter are surrounded by 

 connective tissue, which is continuous with that of the septa 

 between the lobules. In the human liver there is a similar 

 arrangement, but in it the septa of connective tissue do not 

 completely separate the lobules, and, excepting at the inter- 



PIG. 80. Injected liver of rabbit, showing branches to 

 portal vein, capillaries, and the hepatic veins in the centres of 

 two lobules. Frey. 



'Kiernan: Philosoph. Trans., 1833. 



2 Vena3 Centrales, Krugenberg, Miiller's Archiv, 1843. 



