298 A Study of the Structural Unit of the Liver 
would flow through it at once without further filtration through the 
interlobular connective tissue spaces. The course the cinnabar granules 
take also speaks against a direct channel between the perilobular lymph 
spaces and the interlobular lymph channels. A few of the granules enter 
the perilobular lymph spaces, but none of them reach the main lymph 
channels. All of my specimens without exception force me to the conclu- 
sion that there are no direct channels connecting the perivascular and 
perilobular lymph spaces with the lymphatics proper other than the ordi- 
nary spaces between the connective-tissue fibrils of the capsule of Glisson. 
These spaces, however, are relatively large, permitting of a rapid trans- 
fusion through them. 
Injections with a hypodermic syringe into the walls of the smaller 
portal veins naturally fill the surrounding lymphatic vessels, and when 
no valves are in the way the injected fluid passes to the origin of the ves- 
sels, or lacunze, which are located in the center of the portal units. From 
here the fluid passes through the main connective-tissue spaces into the 
perilobular and perivascular lymph spaces, and frequently from them 
into the blood capillaries. When the injection of the lymphatics is made 
through the bile ducts I have always found that there is an extravasation 
at the center of the portal unit, although the bile capillaries are often 
injected to the nodal points. The extravasation does not take place from 
the bile capillaries, but only from the duct as it communicates with the 
capillaries as well as from the larger bile ducts. Such extravasations 
naturally are then taken up by the lymphatics and carried from the liver. 
If after ligature of the bile duct the bile enters the perivascular lymph 
space within the lobule it may still be carried to the lymphatics, as the 
direction of the current of lymph is constantly from the blood capillaries 
to the lymphatics. 
That the blood capillaries of the hyer communicate more freely with 
the lymphatics than do the bile ducts is proved by injecting the bile duct 
and the portal vein with fluids of different color under the same pressure 
at the same time. In all the experiments I made the fiuid injected into 
the vein appeared in the lymphatics first. In many instances beautiful 
injections of the lymphatics were obtained from the vein while the fluid 
injected into the bile duct did not extravasate at all, showing at least 
that the veins communicate with the lymphatics much more freely than 
do the bile ducts. 
It is seen from the above description that the lymphatics of the liver 
do not drain all portions of the liver lobule, but only those portions that 
are formed by the centers of the portal units. There are no lymphatics at 
