322 PROFESSOR FRANK J. COLE 



branches. These ducts are readily identified by their more deeply staining shallow 

 epithelium and closely crowded nuclei.* The contrasted liver tubules, of course, open 

 into them. 



The main or posterior section of the posterior hepatic duct, on being followed 

 backwards from its point of exit from the liver, is found to behave in precisely the 

 same way as the smaller anterior section. Whenever the portal vein gives off a 

 large branch, the hepatic duct detaches a corresponding branch, and this immediately 

 breaks up into a large number of small tubules which at once surround the vein. There 

 is, however, one difference between the two sections of the posterior hepatic duct. The 

 posterior one preserves its identity for some distance within the liver — in fact, as long 

 as the portal vein is represented by a conspicuous vessel. But when the latter splits 

 into two, the hepatic duct is thereupon dissolved into numerous small tubules. 



In places the biliary tubules become enlarged, and here contain a substance which 

 looks very like broken-down blood corpuscles. It is possible this may be a pathological 

 manifestation. 



The anterior hepatic duct leaves the anterior lobe of the liver as two large tubes 

 which, however, immediately join. Each is formed by the junction of two ducts — in 

 one case of two relatively small ducts. These then enter the liver in company with 

 the portal vein. Since the greater part of the lobe lies anterior to the exit of the 

 hepatic duct there is not the same occasion, as in the case of the posterior lobe, for the 

 existence of anterior and posterior sections of the duct, and, as a matter of fact, the two 

 tubes mentioned above are concerned mostly with that part of the lobe anterior to the 

 point of exit. A few smaller tubes pass backwards to drain that part of the lobe 

 posterior to the exit place. The factors of the anterior hepatic duct behave, and are 

 related to the anterior branch of the common portal vein, exactly as in the case of the 

 posterior lobe already described. 



The liver is extremely vascular. It contains large, sometimes very large, irregular 

 blood sinuses, only partially filled with blood, which at first sight appear to have no 

 definite walls. As above stated, other blood spaces have an obvious connective-tissue 

 wall. The former are associated with the sub-intestinal and hepatic veins, the latter 

 with the portal vein. In serial sections I have been able to trace a direct continuity 

 between these two types of spaces. 



In a well-injected liver each tubule is seen to be completely surrounded by a 

 vascular space — in fact so much so that the substance of the liver appears to include 

 more blood tissue than liver tubules. None the less, I have found no clear case of a 

 vessel entering a tubule — they remain always outside them. There are no inter- 

 cellular or intra-tubular vessels. 



Injection from the heart {i.e., via the hepatic arteries) or from the portal vein gives 

 the same .result. A coarse vascular network is disclosed which penetrates everywhere 

 between the liver tubules, and constitutes not a capillary system but a reticular sinus. 



* In one case I found only three cells in transverse section. 



