474 
DR. C. HANDFIELD JONES ON THE 
linear, it is seen to be formed by the apposition of numerous epithelial cells in a 
linear series ; these series are not constituted by a single file of cells, but they are to 
a certain extent superposed, so that one cell may be overlapped by one or more adja- 
cent. No enveloping membrane can be discovered containing the lines of cells ; they 
evidently lie free, side by side, in the interstices of the blood capillaries, and are sur- 
rounded and imbedded in a structureless substance of indistinct granular appearance, 
which probably constitutes their “blastema” or formative material. Each lobule is 
separated from the adjacent ones by narrow spaces, the interlobular fissures of Mr. 
Kiernan ; and where three of these unite there is a triangular interval, the interlobular 
space. Now if the margin of an entire lobule be examined, it is found to be invested 
by a delicate membrane, through which the outline of the last epithelial cells of the 
several linear series may be clearly discerned ; this corresponds to the basement mem- 
brane of Mr. Bowman ; and the perfectly defined and smooth margin of a lobule in- 
vested by it, is strongly contrasted with the irregular jagged appearance of a broken 
edge. Traced laterally, this membrane is found to line the side of one lobule, to form 
the floor of the intervening duct, and then to ascend along the side of the opposite 
lobule, thus investing by a continuous surface the opposite sides of two adjacent 
lobules. Again, if we follow it along the margin of the lobule, we may often assure 
ourselves of its existence for one-half or more of the periphery; but it is rarely 
possible to trace it completely round, inasmuch as the plane of the section scarcely 
ever coincides perfectly with that of the duct; I have however in three or four in- 
stances succeeded in doing so ; and in many others, where after tracing it along a 
great part of the circumference it has for a short distance been lost to view, I have 
obtained assurance of the presence of the duct by appearances of the following kinds, 
viz. the lighter colour and evident depression of the interlobular fissure, the exist- 
ence of an opake deposit occupying the course of the duct, and which had been ob- 
served in other ducts whose cavities had been laid open ; or lastly, by a dark line 
extending from one interlobular space to another, which was formed by the concur- 
rence of the radiating linear series of two opposite lobules, which appear to meet and 
terminate above their common duct. But though the real arrangement be as I have 
now described it, yet in by far the greater number of instances the lobules appear 
to be continuous with each other at one or more points, so that although at one 
level the outline of the lobule be well-defined by the zone of the portal vessel and the 
accompanying duct, yet in all others there is a continuity of tissue, both of the 
capillary and of the epithelial element ; this view, which differs from that of Mr. 
Kiernan, seems to be admitted at present by most observers*. 
It might be objected to the above description, wdiich regards the lobules as em- 
braced by interlobular ducts on every side, that those lobules which form the walls 
of portal canals must be without ducts on the side looking toward the canal, since 
' * I have since ascertained that the livers of different animals vary in this respect ; the lobules of the organ in 
the Pig are separated by fissures exactly in the manner Mr. Kiernan describes. 
