_Nuck_ hath sometime ago demonstrated, that these conglomerate
Glands are a Bundle of small Vessels; that their excretory Ducts are
Continuations of the arterial Ramifications, and that these Glands owe
their Origin to the smallest Branches of the Arteries: These Arteries,
which enter the glandular Substance of the Breasts, are imperceptible
to the naked Eye, and discoverable only by injecting a very fine
Tincture (which _Nuck_ tells us is known to very few Anatomists) into
the Artery; this may be so far propelled, as to render the milky
Ducts conspicuous. For the better Discovery of this Matter, _Nuck_
instituted another Experiment equally curious and useful; having
met a Nipple full of excretory Ducts, he pressed it, and the Breast
adjoining, so as to empty all its Contents, and having pitched upon one
of the widest Ducts, he injected _Mercury_ so artificially, that he
immediately observed the milky Ducts spread like Branchings of Trees;
some Part of the _Mercury_ was carried so far as to enter the Arteries,
whence the milky Vessels were continued.