SECT. 4.
Hence it follows, that these milky Ducts are destitute of Valves, otherwise the Mercury and the injected Liquors would have been obstructed in their Passage. It is indeed observable, that these Canals are in some Places streighter and narrower than in others, so as to give some kind of Obstacle to the Injection; this is not to be imputed to Valves, but to some kind of Hardness peculiar to the Substance of the Glands, by which the milky Vessels are compressed. From hence appears the immediate Inosculation of the milky Ducts, with the small Ramifications of the Arteries, of which these Glands are composed; so that the arterial Blood propels and deposits its chylous and serous Particles by gentle Pressure and Impulse in the milky Ducts, without other Mechanism than bare Straining and Secretion. For the further and more exact Description of these Ducts, see Nuck’s Adenographia.