468 



LIVER. 



[CHAP, xxxni. 



they go. The arrangement of the branches of the portal vein 

 round one of the smallest lobules of the pig's liver, with a few of 

 the lobular capillaries injected, is shown in Fig. 221. 



Hepatic Artery. Many branches of the artery pass to the 

 capsule of the liver, in which they ramify abundantly, forming a 

 network having large meshes. These capsular branches and their 

 anastomoses, are readily injected in the liver of the foetus or 

 child. 



The artery gives off numerous branches in the portal canals. 

 The greater number of these are distributed upon the coats of the 

 ducts. The thick walls of the larger ducts are abundantly sup- 

 plied with arterial blood; but the smaller branches of the duct, 

 the coats of which are extremely delicate, pass through the 

 meshes of an arterial network. In the pig this network may 

 be demonstrated .upon the surface of each lobule, Fig. 222, 

 but in the human subject the branches are less numerous, 

 and are seen only in the interlobular fissures; other branches 

 supply the coats of the portal and hepatic veins. The greater 

 quantity of blood, after passing through these small arteries, is 

 collected by venous radicles which empty themselves into the 

 branches of the portal vein. A few very small arterial branches 

 may be traced from the portal aspect of the lobule for a short 

 distance into its interior, where they join the portal hepatic plexus 



Fig. 222. 



a. Part of arterial ring, with branches ramifying upon th*e capsules of the lobules of the pig's liver. 

 b. Arterial network, c. Portion of lobular capillary network injected from the artery and small 

 branches of the latter entering it. After Dr. Beale. 



