Putting these into several liquors, I found _oyl of Vitriol_, _Spirit of
Urine_, and several other _Saline menstruums_ to dissolve them; and the
first of these in less than a minute without _Ebullition_, Water, and
several other liquors, had no sudden operation upon them. This I mention,
because those liquors that dissolve them, first make them very white, not
_vitiating_, but rather rectifying their Figure, and thereby make them
afford a very pretty object for the _Microscope_.

How great an advantage it would be to such as are troubled with the Stone,
to find some _menstruum_ might dissolve them without hurting the Bladder,
is easily imagin'd, since some _injections_ made of such bodies might
likewise dissolve the stone, which seems much of the same nature.

It may therefore, perhaps, be worthy some Physicians enquiry, whether there
may not be something mixt with the Urine in which the Gravel or Stone lies,
which may again make it dissolve it, the first of which seems by it's
regular Figures to have been sometimes _Crystalliz'd_ out of it. For
whether this _Crystallization_ be made in the manner as _Alum_, _Peter_,
&c. are _crystallized_ out of a cooling liquor, in which, by boyling they
have been dissolv'd; or whether it be made in the manner of _Tartarum
Vitriolatum_, that is, by the _Coalition_ of an _acid_ and a _Sulphureous_
substance, it seems not impossible, but that the liquor it lies in, may be
again made a _dissolvent_ of it. But leaving these inquiries to Physicians
or Chymists, to whom it does more properly belong, I shall proceed.

* * * * *


Observ. XIII. _Of the small _Diamants_, or _Sparks_ in _Flints_._