Franklin P. Mall. 271 
32 is made from a celloidin corrosion specimen of both the portal and 
hepatic systems. The “spiral valve ” of the hepatic vein, which is always 
present in the dog and the cat, is well shown in such specimens. From 
the study of granular injections of the hepatic vein with cinnabar, ultra- 
marine blue, chrome yellow and baryta, it is found that the capillaries 
arise from veins which are about .17 mm. in diameter. This arbitrary 
point, Fig. 32, S, marks the beginning of the sublobular vein, although 
numerous capillaries still arise from it. After its walls become markedly 
thickened capillaries no longer arise from the sublobular vein, but in 
their place smal] veins arise which supply portions of a lobule and there- 
Fig. 36. Photograph of a corrosion preparation of the portal and hepatic 
trees. X 2. At the X two of the terminal hepatic veins anastomose. The 
“special valve’ may also be seen. 
fore cannot be considered central veins. In my study I have called the 
hepatic veins in the neighborhood of .09 mm. in diameter intralobular 
veins, and those .17 mm. or a little larger sublobular veins. In Table VI 
they have been classed respectively under the sixth and fifth orders. 
The form of the hepatic lobule can be well outlined by washing vessels 
of the liver first with saline solution, then with alcohol, after which cin- 
nabar and lamp-black celloidin are injected respectively into the portal 
and hepatic veins. With considerable pressure the capillaries are injected 
more or less with red or with black. Figure 33 is from a specimen of this 
kind with red in the hepatic vein and black in the portal vein. In this 
specimen the lobule was but partly injected with red celloidin and in the 
corrosion but the center of the lobule is shown. ‘To the extent in which 
