476 
DR. C. HANDFIELD JONES ON THE 
support of the contrary view, the suggestion of Mr. Bowman appears to me most 
probable, that the injection urged along the ducts had made its way into the inter- 
stices of the capillaries, and thus given rise to the appearance of a plexus ; and in a 
subsequent part of this paper it will be shown that a condition of the lobules tem- 
porarily exists, in which such an occurrence might easily be conceived to take place. 
Supposing it then conceded that the above account is correct, we may next inquire 
in what manner the structure described subserves the process of secretion as carried 
on in this organ. Now one peculiar circumstance at once arrests our attention, viz. 
that whereas in most other glands the epithelial cells are situated on the free surface 
of the basement membrane, and therefore in the cavity of the duct, they are here 
found on its deep or attached surface ; in explanation of this it may be remarked, as 
Mr. Bowman observes, that the epithelial cells are, in point of function, the real con- 
tinuations of the ducts, and the remarkable linear arrangement which so generally 
prevails, appears to me to suggest the idea that the rows of cells represent an inter- 
mediate stage of the development of primary duct tubules, the cells being apposed to 
each other, as in the formation of an ultimate nerve tube or muscular fibre. That the 
epithelium is the essential agent in the process of secretion, is now I think acknow- 
ledged by the great majority of those who have examined the subject. Mr. Goodsir, 
in his lately published work, has brought together a great number of examples, chiefly 
from the lower animals, in which it is distinctly shown that secretions of various 
kinds are formed during the growth of nucleated cells ; and similar particles, especially 
under certain morbid conditions, may, in the very organ we are now examining, even 
in the human subject, be proved to fulfill the same office. Now where the epithelial 
cells are found on the free surface of the basement membrane, it is easy to conceive 
that the materials assimilated during their growth, are by the dehiscence of the cell, 
or its being cast off during the formation of fresh cells, set free in the cavity of the 
duct ; but in the case of the liver the arrangement is very different, the greater pro- 
portion by far of the secreting cells being remote from any free surface on which 
their contained products might be poured out: the question then presents itself, in 
what manner does the secreted material of the cells find its way into the cavity of 
the surrounding duct? I will now detail the observations I have made which bear 
on this point. 
The ductus communis choledochus of a rabbit was tied, death ensued in about twenty 
hours, apparently from gradual sinking, no traces of inflammation being visible ; the 
gall-bladder was found tolerably full of healthy bile, the liver healthy, with the ex- 
ception of some masses of morbid deposit which I have elsewhere described*; these 
were however quite local. On examining thin sections near the surface, where a good 
view of the lobules and their intervening ducts was obtained, it was manifest, in 
almost every instance, that accumulation of bile had taken place in the centre of the 
lobules, as indicated by a yellow zone of some width surrounding the intralobular 
* Medical Gazette, October 24. 
