132 



PHYSIOLOGY 



CHAP. 



(Fig. 47). Whether these vacuoles leading into the network of 

 the bile canaliculi, and first observed by Pfliiger and by Kupffer, 

 and confirmed by others, are permanent structures, or whether 

 they are only formed at the moment of secretion, or produced 

 artificially by the staining fluids injected through the bile ducts 

 (which may fairly be excluded seeing that nothing of the sort has 

 been met with in other injected tissues), is unknown. 



The peculiar structure of the hepatic parenchyma is determined 

 by the arrangement of its blood-vessels, which (with the lymphoid 

 connective tissue connected with Glisson's Capsule) constitutes 

 the scaffolding or framework of the hepatic cells. Unlike all 

 other organs, the afferent vessels of the liver consist not only of an 





Fio. 47. Section of liver from adult animals, with injected bile capillaries. (Kupffer.) A, bile 

 canaliculi of rabbit's liver, artificially injected from hepatic ducts with Berlin blue solution. 

 They give off minute projections like a pin's head, which penetrate into the protoplasm of 

 the liver cells. B, the same from frog's liver, after natural injection with sulphindigotate 

 of soda. Here the projections form a network of fine fibrils inside the hepatic cells, with 

 terminal dilatations. 



artery the hepatic artery, but also of a vein the portal vein, 

 which is formed by the union of the efferent veins from the 

 stomach, intestine, pancreas, and spleen ; these form a venous 

 trunk with exceptionally robust and muscular walls, and a much 

 larger calibre than the hepatic artery. The efferent vessels are : 

 the hepatic veins, with thin walls, which arise in the portal 

 capillaries, run towards the posterior surface of the liver, and open 

 into the inferior vena cava ; and the lymphatics, which are large 

 and numerous in the liver, originating in the lymph sinuses round 

 the portal capillaries, and which accompany and to a large extent 

 enclose the branches of the blood-vessels, and leave by the portal 

 fissure with the portal vein, the hepatic artery, and the 'bile or 

 hepatic duct. This last leads by the cystic duct to the gall- 

 bladder, and the junction of the two ducts (hepatic and cystic) 

 form the common bile duct or ductus choledochus, which pours 



