In the hepatic structure of the mouse there were three different geometrical areas: the perivascular area of the portal stem, which continued to the preterminal portal branch, of the preterminal vein and of the terminal portal twig, which were considered to be the real functional unit and extended into the neighbouring hepatic lobules.

Mitochondria of the hepatic cells were contained in the perivascular portion adjacent to the portal vessels and were deposited less toward the peripheral portion of the portal vessels.

The pericentral area of the central vein in the hepatic lobule or the structural unit, and the perivascular area of the sublobular vein corresponded to the peripheral zone of the actual functional unit described above.