268 A Study of the Structural Unit of the Liver 
pig the portal unit would have been accepted, for in general either set of 
lobules is only occasionally well outlined and thus marked in some mam- 
mals. In the human liver, as in the dog’s, there are more terminal portal 
twigs than hepatic and this together with other structures which accom- 
pany the portal vein, makes it easy for practical purposes to call the he- 
patic unit the lobule. However, it is just as easy, if not easier, to con- 
sider the portal unit the lobule if one is so inclined. 
From the standpoint of pathology, it is easy to construct a description 
of the liver based upon a portal lobule. Especially marked are these 
lobules in venous hyperemia, in pigmentation and in cirrhosis in which 
Fic. 31. Dorsal view of the same. Gd, gall bladder; wv, umbilical vein; 
S, Spigelian lobe; vc, vena cava inferior. 
there is a marked regeneration arising from the bile ducts. Sabourin” 
has used these arguments successfully in favor of the portal lobule as the 
histological unit of the liver. However, his results are also not new, as 
may be seen by glancing over the historical note accompanying this paper. 
But his point is sound and shows that the liver histology may be con- 
structed around the terminal portal veins as well, if not better, than 
around the terminal hepatic veins. His extensive monograph is illus- 
trated with several hundred diagrams, many of which are fanciful, for 
they are defective in one respect. If a series of circles are crowded to- 
gether to form hexagons and each of the angles is then used as a center 
* Sabourin, Recherches, etc., de la Glande Biliaire. Paris, 1888. 
