Now, in a ripe Feather (as one may call it) it
seems difficult to conceive how the _Succus nutritius_ should be convey'd
to this pith; for it cannot, I think, be well imagin'd to pass through the
substance of the quill, since, having examin'd it with the greatest
diligence I was able, I could not find the least appearance of pores; but
he that shall well examine an unripe or pinn'd Feather, will plainly enough
perceive the Vessel for the conveyance of it to be the thin filmy pith (as
'tis call'd) which passes through the middle of the quill.
As for the make and contexture of the Down it self, it is indeed very rare
and admirable, and such as I can hardly believe, that the like is to be
discover'd in any other body in the world; for there is hardly a large
Feather in the wing of a Bird, but contains neer a million of distinct
parts, and every one of them shap'd in a most regular & admirable form,
adapted to a particular Design: For examining a middle ciz'd Goose-quill, I
easily enough found with my naked eye, that the main stem of it contain'd
about 300. longer and more Downy branchings upon one side, and as many on
the other of more stiff but somewhat shorter branchings. Many of these long
and downy branchings, examining with an ordinary _Microscope_, I found
divers of them to contain neer 1200. small leaves (as I may call them, such
as EF of the first Figure of the 22.
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