LOBULAR STRUCTURE OF THE LIVER. 3 



occupy the interspaces of the lobules, and never penetrate into 

 their interior, they are termed interlobular veins. And in- 

 asmuch as all the interlobular passages of the liver of the Pig 

 contain interlobular veins, these last collectively represent the 

 contour of the lobules ; and further, as the ultimate branches 

 of the interlobular veins are distributed in the septa, these map 

 out the surfaces of the polyhedric 1 lobules, and every lobule lies 

 in a framework of portal vessels, which, however, nowhere 

 anastomoses with the vessels of the adjoining lobule. Both 

 those minute portal branches that lie between the adjacent 

 angles of the lobules and those situated in the septa ulti- 



O A 



mately send numerous capillary branches into the interior of 

 the lobules with which they are in contact, and these form a 

 plexus traversing the entire mass of the lobules, and ultimately 

 discharge their blood into the intralobular veins. 



In the liver of Man the smaller branches of the portal vein 

 also lie in corresponding canals between the angles of the 

 lobuli, invested by connective tissue, though this does not form 

 complete septa between the lobules, but sends only a few fibres 

 between their adjoining surfaces. At the periphery of every 

 such surface the two lobules therefore and this indeed only 

 partially are separated by a little connective tissue, whilst the 

 remainder of the periphery, and the whole of the central por- 

 tion of the applied surfaces, are only theoretically present, 

 because here the substance of the two lobules is uninter- 

 ruptedly continuous. The short terminal branches of the 

 interlobular veins lying in the interlobular spaces penetrate 

 these incomplete septa of connective tissue, and it thus results 

 that the angles and surfaces of the lobules in the liver of 

 Man are similarly defined to those of the Pig by the ultimate 

 ramifications of the portal vein which converge towards 

 the lobuli from different quarters, without however forming 

 any anastomosis at their periphery. From these terminal 

 branches of the portal vein the capillary system of the lobules 

 is then formed just as in the liver of the Pig, with this excep- 

 tion only, that the capillary networks of two adjoining lobules 

 are directly continuous with each other. 



If now in accordance with the above description we repre- 

 sent the hepatic veins as an extensively ramified tree, on the 



B 3 



