384 STKUCTUKE AND PATHOLOGY 



mouths to their blind or anastomosing extremities. In the 

 liver the arrangement is different, although in principle the 

 same. Tracing the structure of the ducts from the transverse 

 fissure up along the portal passages, where they accompany 

 the vena portse and hepatic artery on to the compressed spaces 

 between the lobules, and where they form a network, they 

 consist of a fine membrane, having vessels on its external, 

 compressed particles (epithelia) on its internal surface. At 

 the outer surface of the lobules, the fine membrane of these 

 ducts does not seem to enter the lobules ; only the portal 

 vessels, and the secreting particles, the latter being grouped 

 around the former, so as to leave passages continuous with 

 the plexus of ducts on the external surface of the lobule, con- 

 verging, and at the same time communicating, with one 

 another from that surface to the centre of the lobule. If, then, 

 we suppose the portal vessels, which pass in at the outer part 

 of the lobule, the hepatic vein, which passes out at the base, 

 and the intermediate capillary plexus to be removed, we shall 

 have remaining in a lobule only a mass of flattened particles 

 so arranged as to exhibit two sets of passages one occupied 

 by the vessels of the lobule, and communicating on the one 

 hand with the portal, and on the other with the hepatic vessels. 

 The other set of passages within the lobules are continuous 

 with the hepatic ducts, and are the ducts of the lobule itself. 

 The difference, then, between an extra and an intra-lobular duct 

 is that the former possesses a fine membrane between its 

 vessels and secreting particles ; the latter presents no such 

 membrane, the particles being so arranged as to be in the 

 immediate neighbourhood of bloodvessels, and to leave free 

 intercellular passages outwards for their secretion. 



The lymphatics of the liver I am inclined to believe, for 

 reasons which I cannot enter upon at present, to take their 

 origin in the intercellular spaces of the lobule, to acquire 

 distinct walls in the compressed portal spaces between the 



