other body,
for many other fluid bodies will do the same thing) which breaking out of
the lesser, were collected into very large bubbles, and so might make their
way out of the Sponge, and in their passage might leave a round cavity; and
if it were large, might carry up with it the adjacent bubbles, which may be
perceiv'd at the outside of the Sponge, if it be first throughly wetted,
and sufferr'd to plump itself into its natural form, or be then wrung dry,
and suffer'd to expand it self again, which it will freely do whil'st
moist: for when it has thus plump'd it self into its natural shape and
dimensions, 'tis obvious enough that the mouths of the larger holes have a
kind of lip or rising round about them, but the other smaller pores have
little or none. It may further be found, that each of these great pores has
many other small pores below, that are united unto it, and help to
constitute it, almost like so many rivulets or small streams that
contribute to the maintenance of a large River. Nor from this _Hypothesis_
would it have been difficult to explicate, how those little branches of
_Coral_, smal _Stones_, _shells_, and the like, come to be included by
these frothy bodies: But this inded was but a conjecture; and upon a more
accurate enquiry into the form of it with the _Microscope_, it seems not to
be the true origine of them; for whereas Sponges have onely three arms
which join together at each knot, if they had been generated from bubbles
they must have had four.

But that they are Animal Substances, the _Chymical_ examination of them
seems to manifest, they affording a volatil Salt and spirit, like
_Harts-Horn_, as does also their great strength and toughness, and their
smell when burn'd in the Fire or a Candle, which has a kind of fleshy sent,
not much unlike to hair. And having since examin'd several Authors
concerning them, among others; I find this account given by _Bellonius_, in
the XI. _Chap._ of his 2d Book, _De Aquatilibus_. _Spongiae recentes_, says
he, _a siccis longe diversae, scopulis aquae marinae ad duos vel tres
cubitos, nonnunquam quatuor tantum digitos immersis, ut fungi arboribus
adhaerent, sordido quodam succo aut mucosa potius sanie refertae, usque
adeo foetida, ut vel eminus nauseam excitet, continetur autem iis cavernis,
quas inanes in siccis & lotis Spongiis cernimus: Putris pulmonis modo
nigrae conspiciuntur, verum quae in sublimi aquae nascuntur multo magis
opaca nigredine suffusae su