STRUCTURE OF THE LOBULES OF THE LIVER. 7 



meshes, is best displayed in those sections which have been 

 made through the whole length of the intralobular vein. In 

 such instances the lobules resemble a leaf, the midrib of which 

 is formed by the hepatic vein. The trunk of the intralobular 

 veins gives off capillaries on each side, which pursue a parallel 

 course, communicating at short distances by means of trans- 

 verse branches, like the lateral veins of a leaf, whilst the intra- 

 lobular vein breaks up at its extremity into a group of radially 

 directed capillaries ; when the section is carried at right angles 

 to the intralobular vein, this appears as a circular space from 

 which the capillaries radiate outwards in all directions. It is 

 only rarely, however, that we can follow one individual capil- 

 lary through the whole of its course, because they are not 

 given off at exactly right angles to the central trunk, but 

 more or less obliquely. In a similar manner the meshes of 

 the capillary plexus appear shorter than natural, because the 

 section is not quite parallel to their plane. When the section 

 has been carried in a direction parallel to, but not through, the 

 long axis of the intralobular vein, a considerable number of 

 radial capillaries will always be transversely divided, and their 

 sections appear in or near the middle of the section of the lobule, 

 whilst more externally they are more and more obliquely 

 divided, until near the periphery they assume quite an irregular 

 arrangement. 



From a comparison of these simplest forms of section an 

 interpretation may be given of the more intricate appearances 

 presented where the section has been made at an oblique angle 

 to the axis of the intralobular vein, whether the latter has 

 been divided or not. In every section of the liver presenting 

 a considerable surface, examples may be met with in which 

 the lobules have been divided in the most various directions, 

 because their axes really lie at all angles to one another. It must 

 follow as a consequence of these arrangements, that the cases 

 where the radiating capillary meshes are seen in their whole 

 extent on one plane must be relatively rare, and it is easy 

 therefore to fall into error respecting the arrangement of the 

 capillaries. 



Moreover the arrangement of the hepatic cells, since this is 

 determined by that of the capillaries, varies considerably with 



