ne to the bladder, which hath wide conduits or passages, that
give room for the urine and humour whereof gravel is engendered, which
waxes thick, and seats itself, as the manner of it is. In old men it is
the reverse, for they have wide passages of the veins, back and kidneys,
that the urine may pass away, and the earthly humour congeal and sink
down; the colour of the gravel shows the humour whereof the stone comes.

Q. Why is it, if the stone do congeal and wax hard through heat, we use
not contrary things to dissolve it by coldness, but light things, as
parsley, fennel and the like? A. It is thought, to fall out by an
excessive scorching heat, by which the stones do crumble into sand, as
in the manner of earthen vessels, which, when they are overheated or
roasted, turn to sand. And by this means it happens that small stones
are avoided, together with sand, in making water. Sometimes cold drink
thrusts out the stone, the kidneys being stretched and casting it out by
a great effort; thus easing the belly of its burden. Besides, it often
happens that immoderate heat of the kidneys, or of the veins of the back
(through which the stone doth grow) is quenched with coldness.

Q. Why is the curing of an ulcer or bile in the kidneys or bladder very
hard? A. Because the urine being sharp, doth ulcerate the sore. Ulcers
are worse to cure in the bladder than in the kidneys, because urine
stays in the former, but runs away from the latter.

Q. Why do chaff and straw keep water hot, but make snow cold? A. Because
the nature of chaff wants a manifest quantity; seeing, therefore that of
its own nature, it can easily be mingled, and consumed by that which it
is annexed onto, it easily assumes the same nature, and being put into
hot things, it is easily hot, heats again, and keeps hot; and on the
contrary, being made cold by the snow, and making the snow cold it keeps
in its coldness.

Q. Why have we oftentimes a pain in making water? A. Because sharp
choler issuing out, and pricking the bladder of the urine, doth provoke
and stir up the whole body to ease the part offended, and to expel the
humour moderately. This doth happen most of all unto children, because
they have moist excrements by reason of their often drinking.

Q. Why have some medicines of one kind contrary effects, as experience
proves; for mastich doth expel, dissolve and also knit; and vinegar
cools and heats? A. Because there are some small invisible bodies in
the