BLOOD-VESSELS OF THE LOBULES. 871 



the vein, which are here very thin, giving a tesselated appearance, each little 

 polygonal space representing the base of a lobule, and having in its centre a 

 small spot, which is the mouth of the intralobular vein. When divide! in 

 the direction of a sublobular vein, the attached lobules present a foliated 

 appearance, for that part of their surface which is not in contact with the 

 vein is itself slightly lobulated. Cut in a transverse direction, the lobules 

 present a polyhedral form. 



The hepatic substance, as exhibited in the arrangement of each lobule, 

 consists of masses of cells and a copious vascular network, closely inter- 

 woven, with the intervention of little other tissue. For the sake of con- 

 venience, the vascular structure of the liver may be considered first. 



Blood-vessels. The hepatic veins commence in the centre of each lobule 

 by the union of its capillary vessels into a single independent intralobular 



Fig. COS. CAPILLARY NETWORK OP THE LOBULES OP THE RABBIT'S LIVER (from 



Kolliker). ^ 



The figure is taken from a very successful injection of the hepatic veins made by 

 Harting : it shows nearly the whole of two lobules, and parts of three others : p, portal 

 branches running in the interlobular spaces ; h, hepatic veins penetrating and radiating 

 from the centre of the lobules. 



vein, as already stated. These minute intralobular veins open at once into 

 the sides of the adjacent sublobular veins. The sublobular veins are of 

 various sizes, and anastomose together. Uniting into larger and larger 

 vessels, they end at length in hepatic venous trunks, which receive no 

 intralobular veins. Lastly, these venous trunks, converging towards the 

 posterior border of the liver, and receiving in their course other small sub- 

 lobular veins, terminate in the vena cava inferior, as already described. In 

 this course the hepatic veins and their successive ramifications are unac- 

 companied by any other vessel. Their coats are extremely thin j the sub- 

 lobular branches adhere immediately to the lobules, and even the larger 

 trunks have but a very slight areolar investment connecting them to the 

 substance of the liver. Hence the divided ends of these veins are seen upon 

 a section of the liver as simple open orifices, the thin wall of the vein being 

 surrounded closely by the solid substance of the gland. 



The vena portse and hepatic artery, which, together with the biliary ducts, 



