THE LIVER AND BILIAKY APPARATUS. 187 



connective tissue which surrounds the latter. The hepatic arte- 

 ry also gives off nutrient branches which supply its own walls, 

 and small twigs, which, piercing the substance of the liver be- 

 tween the lobules, supply the branches of the hepatic vein. 

 The ultimate branches of the artery are contained within the 

 interlobular canals, and break up into capillaries at the peri- 

 phery of the lobules, which they traverse for a short distance 

 to form a distinct network. There is no communication between 

 the intralobular capillaries of the hepatic artery and those of 

 the portal vein. The former seem destined to supply the ad- 

 jacent vessels, and probably the small amount of iutralobular 

 connective tissue to be spoken of hereafter. 



It has been thought by some (Chroaszewski, Bindfleisch, and others) that the 

 capillaries of the hepatic artery end midway between the interlobular and cen- 

 tral veins, within the lobule. Beale and Kiernan have noticed that an arterial 

 branch here and there enters a lobule ; while Theile, Davis, and others describe 

 a capillary network about the periphery of the lobules. 



Finally, branches of 0.05 to 0.1 mm. in diameter are dis- 

 tributed to the capsule of the liver, where they break up into 

 capillaries, radiating in all directions and anastomosing with 

 each other to form "a large-meshed network, which communi- 

 cates with the capillaries of the phrenic, mammary, and supra- 

 renal arteries. This plexus empties into small twigs, the so- 

 called inner roots of the portal vein. 



The capillaries of the liver may be injected either through 

 the hepatic or portal vein, or both, as before stated. For in- 

 jecting the hepatic artery the author prefers his cold solution 

 of carmine-glycerine. 1 The gland to be injected must be as 

 fresh as possible. If, for example, a dog be selected for this 

 purpose, the abdomen should be opened and the animal allowed 

 to bleed to death by section of the vena cava. Now introduce 

 into the hepatic artery the canula of a syringe tilled with the 

 carmine-glycerine, secure it in place and inject. Harden the 

 organ in alcohol, cut sections, and mount in balsam. The liver 

 will not be uniformly injected, and only those portions can be 

 utilized in which the injected mass seems to be widely diffused. 



If, in addition to the artery, the hepatic vein be injected 

 with a blue colored mass, beautiful results may be obtained. 

 Sections in which the lobules are cut transversely show the 



1 See chapter on the Kidney. 



