STRUCTURE OF THE LIVER. 255 



rangement is well seen in Fig. 86, which represents a trans- 

 verse section of a lobule. The smaller branches of the portal 

 vein being closely surrounded by the lobules, give off directly 



FIG. 86. 



Cross-section of a lobule of the human liver, in which the capillary network be- 

 tween the portal and hepatic veins has been fully injected (from Sappey) 60 j. 

 Section of the iw/ralobular vein; 2, its smaller branches collecting blood from the 

 capillary network ; 3, tnterlobular branches of the vena portse with their smaller 

 ramifications passing inwards towards the capillary network in the substance of 

 the lobule. 



veins (see Fig. 85) ; but here and there, especially 

 where the hepatic artery and duct intervene, branches called 

 vaginal first arise, and breaking up in the sheath are subse- 

 quently distributed like the others around the lobules and be- 

 come mferlobular. The larger trunks of the portal vein being 

 more separated from the lobules by a thicker sheath of Glisson's 

 capsule, give off vaginal branches alone, which, however, after 

 breaking up in the sheath, are distributed like the others be- 

 tween the lobules, and become iwferlobular veins. 



The small mralobular veins discharge their contents into 

 veins called sitMobular (Fig. 88), while these again, by their 

 union, form the main branches of the hepatic vein, which leaves 

 the posterior border of the liver to end by two or three prin- 

 cipal trunks in the inferior vena cava, just before its passage 

 through the diaphragm. The s-u61obular and hepatic veins, 

 unlike the portal vein and its companions, have little or no 

 areolar tissue around them, and their coats being very thin, 



