306 A Study of the Structural Unit of the Liver 
rectly into the stomach from which it flowed over into the intestine and 
backed up into the bile duct. Within the liver it filled the main trunks 
which correspond with those of the portal vein and then filled a capillary 
network around portal branches of the first order. An illustration of 
this specimen is given in Fig. 73. This figure shows that the vessels 
Gao: 
Hires vale. Mies 2% 
Figs. 68, 69, 70, 71 and. 72. Golgi specimens showing the terminal portal 
twigs with their surrounding bile ducts and capillaries in longitudinal sec- 
tion in fetal pigs 8, 16, 19, 21 cm. long, and in the adult pig. Xx 53. After 
Hendrickson. 
pictured in Figs. 65-67 are probably of the:second order, while that in 
Fig. 64 is of the first order and, therefore, represents a main trunk. 
The bile duct-system can be injected with greater ease in older em- 
bryos, for in embryos over 15 em. long the injection may be made di- 
rectly through the gall bladder. It is unnecessary to give all intermedi- 
ate stages, for Fig. 74, which is from an embryo 20 em. long, helps to 
tell the whole story. With it may be compared Figs. 68-71, for one 
gives the main trunks and the terminal plexus and the other gives the 
terminal plexus and the bile capillaries. 
