Bae eee of the Human Liver. 89 
examining small fragments of injected liver under water by strong 
reflected light. The objective used for this purpose must be of a 
low power, and of the best quality. 
If a fragment is taken in which the network of biliary tubules 
is injected with blue, and that of the blood-vessels—from the hepatic 
veins—with white, the capillaries of both can be seen as they cross 
each other. Close study is required for this examination, and due 
allowance has to be made for the transparency of the colours. 
Moreover, the character of the networks and the diameters of the 
interspaces between their capillaries—in places where only one or 
the other is injected—should be critically observed, in order to 
compare them with those in other places where both are injected. 
T can highly recommend the dissection and examination of small 
injected fragments under water; the most satisfactory results are 
obtained from it. 
The conclusions which I have drawn, in regard to the network 
of “biliary tubules” in the parenchyma of the liver, are not the 
results of mere accidental observations on a few specimens. On 
the contrary, | have examined many hundreds, nay, many thou- 
sands of thin transparent sections, and also small fragments of 
injected liver. The great rapidity with which I can produce sec- 
tions of great thmness and large size by means of my apparatus 
enabled me to do so. If well-injected portions of the liver are ex- 
amined in the manner I have indicated, my statements will be found 
correct in every instance. 
In the fresh uninjected specimens, the commencement of the 
ultimate branches of the hepatic duct in a capillary network can also 
be demonstrated ; this is, however, attended with more difficulties 
than the demonstration by injection. It is done by the aid of the 
microscopic dissector as follows:—A portion of fresh liver is put 
under water, and a very fine probe introduced into a small branch 
of the hepatic duct; the latter is then carefully traced to its finer 
ramifications—under a magnifying power of 3 to 4 diameters—by 
separating it from the surrounding parenchyma. When it cannot 
be pursued any further without the risk of tearing it, it 1s separated 
from the whole with a very small portion of that parenchyma to 
which it adheres. The fragment is now placed on a glass slide, 
provided with a little spring, which, by pressing upon the duct, 
prevents the fragment trom being: displaced. Well covered with 
water, it is placed on the dissecting stage, and under a magnifying 
lens of {ths diameter, dissected by means of fine curved needles. 
The object in view is to trace the duct to its finest branches as far 
as the low magnifying power will allow; and this is accomplished 
by a mere loosening of the tissues, in order to liberate the cells 
from the capillary vessels without tearing the latter. The fragment 
should be washed several times. Being thus far dissected under a 
