Franklin P. Mall 307 
In the adult liver the artery communicates with the lobule throughout 
the extent of the vessels of the sixth order; the connection between bile 
ducts and bile capillaries is probably even more extensive. No bile capil- 
laries arise from bile ducts of the fourth order, the liver tissues in their 
immediate neighborhood being drained by the plexus of the fifth and 
7 
x 
at 
Fie. 73. Bile ducts of a pig, 10 cm. long, injected with India ink. x 60; II, 
portal branches of the second order; III, portal branches of the third order. 
From a specimen made by Mr. Eben Hill. 
sixth orders. So in the center of the portal unit the branch of the portal 
vein ramifies, while along a portion of its axis the artery and duct spread ° 
out. The unit is bounded on its periphery by a number of intralobular 
veins and nodal points, as shown in Fig. 1. 
In the development of the liver the shifting of the peripheral plexus 
23 ; 
