.388 
DR. LIONEL BEALE ON THE 
These facts appear to me to militate strongly against the notion of these ducts 
being modified and anastomosing mucous glands, as Theile supposes. From their 
arrangement it seems not improbable that they are really altered secreting tubes, and 
at one time formed a part of the secreting structure of the liver. As the portal vein 
increases in size at the termination of intra-uterine life, it is not unreasonable to 
suppose that some of the hepatic tissue close to it vrould be removed to some extent, 
to make room for the enlarged vein; in such a case, many of the vessels would 
degenerate into fibrous tissue, and the branched and anastomosing vasa aberrantia 
would represent all that remains of the hepatic tubular network. 
In the very thin edge of a horse’s liver which was composed principally of fibrous 
tissue, I have been able to trace the gradual alteration of the ducts and the ultimate 
complete disappearance of secreting cells. 
Spread out, as it were, upon the surface of the portal vein in the rabbit, there is a 
very thin layer of hepatic tissue, and I have been enabled to trace the different 
stages between the vasa aberrantia and the cell-containing network, most distinctly, 
in a specimen in which the ducts were injected, and the vein distended with 
plain size. 
Function of the glands and vasa aberrantia . — To the sacculi of the ducts, the office 
of secreting the mucus in the bile has been assigned, but cavities opening into a 
tube by a narrow neck, not the inch in diameter, seem ill-adapted for 
pouring out a viscid tenacious mucus ; neither is it easy to suppose how this mucus, 
secreted at certain points, would become thoroughly mixed with the mass of the 
bile as it flowed through the ducts. If these cavities were filled with mucus, one 
would hardly expect that injection would enter them so readily as it does. The 
complicated and highly tortuous vasa aberrantia possess no characters which would 
lead to the inference of their being mucous glands. 
Again, the bile of the rabbit, in which animal these glands are very few in number, 
and only found upon the largest ducts, affords as bulky a precipitate of mucus upon 
the addition of alcohol as that of the pig, in which these glands are so numerous and 
so distinct. 
It seems highly probable that these little cavities, as they are found in the adult 
liver, are to be looked upon as reservoirs for containing bile, whilst it becomes inspis- 
sated and probably undergoes other changes. The numerous vessels and lymphatics 
which surround them, and the similarity of arrangement of those around the vasa 
aberrantia, and of the vessels of the gall-bladder, still further strengthen this view 
of their office. I have not yet minutely investigated the arrangement of the glands 
of the ducts in many different animals, nor have I been able to ascertain if ducts, 
corresponding to the vasa aberrantia, are usually present. I have preparations 
showing them in the pig, in the rabbit, and in the monkey. 
