SECRETORY APPARATUS OF THE LIVER. 
477 
vein; no other change from the usual appearance was observed. Now this case pre- 
sents, I think, the earliest effect of interruption to the flow of the secretion, and the 
appearance noticed seems to point out the exact point where the secreting process 
has its first origin, viz. in the commencement of the rows of cells surrounding the 
central axis of the lobule ; here, though in so remote a situation, bile is formed, 
and from hence it is doubtless transmitted. 
In many livers I have observed a remarkable difference between the condition of 
the peripheral cells adjoining the duct and those situated more centrally, while those 
in the interior appeared of their usual pale or light yellow colour ; the terminal zone 
was of a much darker and more opake aspect ; and often, where the cavity of the duct 
in the fissure was not exposed, its course was manifestly indicated by this dark tract, 
extending from one interlobular space to another; on more particular examination 
this dark aspect was found to depend on the presence of very numerous oil-globules 
in the cells which intercepted the light. Now as we find one or two minute oil-globules 
in almost every cell, the conclusion seems quite legitimate, that where these are found 
greatly multiplied, the cell which has produced them must be in a much more 
advanced state than those which contain but a few. In a human liver which ap- 
peared perfectly healthy I made an observation of similar import ; the section had 
laid open the cavity of a duct for some distance, the margin of which on each side 
presented a perfect fringe of cells containing bile, while for a short space further on 
the course of the unopened duct was indicated by a yellow tract of cells extending 
above it, whose deep biliary tinge contrasted strongly with the pale tint of the sur- 
rounding substance ; in several other ducts of the same liver a similar condition was 
observed. These observations render it nearly certain that the secreting process 
reaches its termination at the margin of the lobule, and I shall now endeavour to 
show in what manner the secretion is discharged into the cavity of the duct. The 
appearance which the margin of a lobule presents when the process of secretion has 
been proceeding actively, differs much from that which is observed when the lobule, 
so to speak, is quiescent; in the latter case, as I have described it, the margin is 
well-defined, and bounded by a distinct basement membrane, while the terminal cells 
of the linear series contain few and minute oil-globules, and do not appear to pro- 
ject outwards in any degree ; in the other case the margin of the lobule has an opake 
cloudy appearance from the multitude of oil-globules ; several cells are seen project- 
ing into the cavity of the duct, giving the wall occasionally a tuberculated appear- 
ance ; these cells contain oil-globules, and their wall is sometimes so extremely 
delicate as to be barely perceptible, even under a high power. Very many oil- 
globules are also seen, which lie evenly in contact with the sides and floor of the 
duct ; it is difficult to determine whether these have escaped from their cells or not ; 
it seems probable, however, that they are for the most part free, having recently been 
liberated by the solution of their cell-wall. The margin of a lobule in the condition 
now described presents no trace of basement membrane, the cells themselves form 
