It was somewhat surprising to me, and not a little interesting, to find
that the ducts have a decidedly richer blood supply than the gland
substance proper, the meshes of the capillaries covering the ducts very
closely indeed.
I will also call attention to the fact that, along the terminal portions
of the ducts, no arteries or veins can be seen; and what is still more
important, no free nerve-fibres can be discovered. Following the ducts
outwards, as these attain larger dimensions, and especially where they
give off side branches, we find arteries and veins accompanying them,
and there will also be found along-side of them fine nerve-branches. So
much is certain, that in that region, where arteries and veins are not
to be seen, there are also no separate nerve twigs, and that here the
union or coalescence of nerve and tissue which the nerves are to
influence must have taken place. If one considers the fine meshes of the
capillary network enveloping the ducts, and keeps in mind the abundance
of nuclei belonging to the capillary, the membrana propria and the duct
cells proper, he can imagine how difficult it must be to follow the
course of the nerves through and among all these structures. That it has
been impossible for me to separate capillary and membrana propria, has
been mentioned.