Monthly Miro of the Human Liver. 91 
tubules” of the adjacent parenchyma; they may be recognized by 
their characteristic constrictions and by their faintly blue colour. 
The latter fact is easily explained when we consider that the greater 
part of the Prussian blue, with which the injecting matter is coloured, 
is retained in the hepatic ducts and in the network of “biliary tu- 
bules;” when the material reaches the lymphatics the amount of 
colour is so small as to render them only faintly blue. 
In thin sections of injected human liver we frequently meet 
with longitudinal sections of intra-lobular hepatic veins, in which 
the greater part of the vessel—and with it the colour with which 
it was filled—is removed. In such instances the finer lymphatic 
branches, running parallel with the vein, can often be seen, as they 
arise from the bilary tubules. 
Sometimes, in minute dissections of the smaller branches of the 
portal vessels and the duct, fine lymphatics are seen, as they come 
from the parenchyma to accompany the vessels and ducts. 
The most satisfactory observations I made to determine the 
origin of the lymphatics in the network of biliary tubules was in 
the liver of the sheep. The results of these experiments were so 
conclusive that they removed all doubt from my mind in regard to 
this subject. They were as follows:—An uninjured liver of the 
sheep was taken, and a small canula, with an orifice of about 2; of 
an inch in diameter, inserted into the hepatic duct. Being placed 
into the basin of my injecting apparatus, the canula was connected 
with the latter, and everything else prepared and adjusted in order 
to inject it in the manner as described in that section of this memoir 
which treats on the subject of “minute injections,” with the descrip- 
tion of the apparatus. By exhausting the air from the interior of 
the basin, it 1s also exhausted from the interior of the hepatic ducts ; 
at the same time, its: pressure is removed from around the organ, 
and also from the cut ends of the large lymphatic vessels, which 
emerge from the liver alongside of the portal vessels, and those 
coming from those lymphatic glands near the vena porta. As soon 
as the communication between the interior of the hepatic ducts and 
the interior of the basin was cut off, and that with the injecting 
liquid—coloured with Prussian blue— established by a slight turn 
of the intervening. stop-cock—the liquid in the glass tube com- 
menced to descend very slowly by its own weight and the pressure 
of the atmosphere. Soon after, the patches appeared at the surface 
of the liver, indicating the arrival of the blue injecting material in 
the “biliary tubules” of those places; but at the same time, it also 
issued from the open mouths of the large lymphatic vessels. When 
the vacuum in the basin was destroyed by the re-admittance of the 
atmosphere, the pressure of the latter upon these open lymphatics 
arrested the flow of the coloured liquid from their cut ends, and 
also its descent in the glass cylinder; this, however, was re-esta- 
VOL. IV. H 
