The vaginal ducts pass transversely through the capsule of Glisson, by which they are enve loped in common with the portal vein and hepatic artery, and divide into numerous small branches which assist in forming the vaginal plexus. From the plexus of ducts two kinds of branches are given off, the interlobular, which run along the margins of the interlobular fissures and enter the interlobular spaces to be distributed upon the capsular surfaces of the lobules ; and the lobular, which enter the sub stance of those lobules which form the parietes of the portal canals. In the smaller portal canals the vaginal branches and plexus are situated only on the portal side of the canal, the interlobular branches, on the side nearest the duct, passing directly into the interlobular spaces. " The transverse branches and those which arise immediately from them do not anastomose with each other, but the smaller branches sometimes appear to do so; - I cannot, however," says Kiernan, " from dissection, affirm that they do, for those which appear to anastomose are exceedingly small vessels and meet each other at the spaces, hence it is diffi cult to ascertain whether they really anastomose or enter the spaces together without anasto mosing." tutes the principal part of the substance of the lobule, and seen through the meshes of the portal venous plexus, gives rise to the appear ance of acini or of crecal terminations of ducts. The ultimate terminations of the ducts have not yet been seen; they are imagined by Muller to end in " short pannicle-like tufts closely interwoven together," and he supports his opinion by citing the circumstance of the ducts in the embryo of the fowl and larva of the frog ending in twig-like terminations. Kiernan inclines to the opinion that they termi nate in loops, although he says nothing which could lead us to suppose that he rejects the possibility of their terminations being ccecal. Both authors agree that they end by closed extremities. It is this plexus which constitutes the true glandular portion of the liver.
Muller, in reference to the terminations of the ducts in anastomosing plexuses, states, that the history of the development of the organ is opposed to the belief in the existence of anas tomoses. Certainly, if we are to credit the principle which he himself has established for the development of glands, viz. that " however various the form of the elementary parts, all secreting glands without exception follow the same law of conformation," the same process must take place in all ; and analogy would lead us to infer that a plexiform anastomosis would be the arrangement of the terminal ducts in so complicated a gland as the liver of the adult, whatsoever it may happen to be in the unde veloped organ of the embryo. That there is nothing irrational in this opinion we would turn for proof to another page of his Physiology, where he observes, " in the scorpion, as I have discovered, the tubes (of the testis) anastomose, forming loops." Again, he says, " Lauth has but once seen a seminal canal ending with a free extremity in the human testis. Krause has seen such free ends of the tubuli seminiferi frequently, and confirms the opinion of their terminating in that way as well as by anasto mosis. Lauth attributes the circumstance of
free extremities of the tubes being so seldom seen to their uniting with each other so as to form loops. Ile describes the division and reunion of the tubes to be so frequent that in a small portion which he spread out, and in which there were about forty-nine inches of tube, he found about fifteen anastomoses. It is, however, only towards their extremities that the seminal tubes anastomose thus freely. The discovery of the anastomoses of the seminal tubes is perfectly original." Krause observes the same fact also with regard to the uriniferous ducts. Now I would ask why, if the ducts of the seminal gland and uriniferous gland anastomose so freely, the ducts of the biliary gland should not do the same ? And why, if the anastomoses of the seminal ducts be a dis covery so original, the less easily demonstrable fact of the anastomoses of the biliary ducts, discovered 'by Kiernan, may not be equally original ? I speak from laborious research upon this subject, and surely there cannot be a com parison between the difficulty of unravelling the simple ducts of the testis and the compli cated and minute masses of the biliary ducts, an aggregation so intricate that Muller acknow ledges it " difficult to decide the question." The above facts of the anastomoses of the seminal and uriniferous ducts would, in my mind, were other evidence wanting, be a cir cumstance powerfully aiding my belief in the anastomoses of the biliary ducts; but the sub ject is not without its proofs, and these, as it appears to me, from careful examination, incon testible. " The left lateral ligament," says Kiernan, " may be considered as a rudimental liver, in which this organ presents itself to our examination in its simplest form. From that edge of the liver connected to the ligament, numerous ducts emerge, which ramify between the two layers of peritoneum of which the ligament is composed." " These duct3, the smallest of which are very tortuous in their course, divide, subdivide, and anastomose with each other. They are sometimes exceedingly numerous, two or three of them in such cases being of considerable size; some of them, as Ferrell)" (by whom they were discovered) " says, frequently extend to the diaphragm and ramify on its inferior surface. They sometimes extend only half way up the ligament, where they divide into branches, which forming arches (fig. 41,) return and descend towards the liver, anastomosing or being continuous with other ducts issuing from it. The spaces between the larger or excreting ducts are occupied by plexuses of minute or secreting ducts." " Branches of the portal and hepatic veins, with arteries and absorbents, also ramify in the ligament, which, including between its layers a plexus of secreting and excreting ducts, with bloodvessels ramifying on their parietes, ad mirably displays the structure of the liver." The same appearances are seen in the bands which sometimes arch over the vena cava and longitudinal fissure, when they are sufficiently thin.