ARRANGEMENT OF THE BILIARY DUCTS. 
381 
tubular raembrane contracts upon its contents. The tubes therefore become much 
narrower, and, except in the highly refracting nature of the contents, the altered 
cell-containing network closely resembles that of the capillaries. 
In a properly prepared liver, it is often possible to show the cell-containing net- 
work in one section and the capillary network in another. When the vessels are 
distended with clear size, the meshes of the cell-containing network are seen ; but if 
a section be well washed and placed in glycerine, the sharp well-defined outlines of 
the capillary vessels are brought into view. In such a section from which the cells 
have been removed, I have seen in some places, just at the thin edge of the specimen, 
stretched across the space between two capillary vessels, the exceedingly delicate 
basement membrane of the tube in which the cells lie, recognizable rather from the 
small quantity of debris and granular matter which adheres to it, than from any 
positive characters distinguishable in the membrane itself. This appearance can 
only be seen under the influence of a very dull light. 
The network is capable of being distended to a considerable extent in every part 
of the lobule without rupture. Often the injection accumulates to such an extent as 
completely to obscure the cells, and in consequence of the pressure thus caused, the 
vessels are rendered invisible. Even in such specimens the appearance cannot be 
mistaken for extravasation or vascular injection. In tubes which are only partially 
injected, the injection often accumulates a little on each side, gradually shading off 
as it were towards the centre, while towards the adjacent capillary vessel it forms a 
distinct, well-defined and dark line. 
The cells which escape into the surrounding fluid from an injected specimen have 
portions of injection adhering to them, or are deeply stained with it. 
A portion of the cell-containing network of the human subject injected is shown 
in Plate XV. fig. 19. The cells represented in the drawing are much altered from 
the mode of preparing the specimen. Their position, however, is shown. In the pig, 
portions of the cell-containing network, in different states, are represented in Plate 
XV. figs. 23, 24, 26, 28. In the seal, in Plate XIV. figs. 15 & 16. In the rabbit, in 
fig. 11 c. In the dog, in Plate XV. fig. 18. In the human foetus, in Plate XV. 
fig. 17, and in Plate XIV. fig. 12. 
If a section be made through the hepatic tissue exactly at right angles to a small 
branch of the intralobular vein, the cells are seen to form rows which radiate from 
the centre towards the circumference of the lobule, as has been noticed by Muller, 
Valentin, Bowman, Theile, Gerlach and others. In sections made in many other 
directions this radiated arrangement is not to be shown. The drawing in Plate I. 
fig. 1 (not published) is an exact copy of a section of horse’s liver, and is the most beau- 
tiful specimen of this arrangement which I have seen. The rows increase in number 
as they pass from the centre. They are connected at irregular intervals by oblique or 
transverse branches, often much narrower than a cell, and containing only nuclei and 
granular matter. These communicating branches are best seen in injected specimens. 
3 e 
MDCCCLVI. 
