CHALK-Stones, in medicine, signify the concretions
of calcareous matter in the hands and feet of people
violently afflicted with the gout. Lewenhoeck has
been at the pains of examining these by the micro-
scope. He divides them into three parts. The first
is composed of various small parcels of matter looking
like white grains of sand; this is harder and drier,
and also whiter, than the rest. When examined with
large magnifiers, these are found to be composed of
oblong particles laid closely and evenly together:
though the whole small stones are opaque, these com-
ponent parts of them are pellucid, and resemble pic-
ces of horse-hair cut short, only that they are some-
what pointed at both ends. These are so extremely
thin, that Mr Lewenhoeck computes that 1000 of
them placed together would not amount to the size of
one hair of our heads. The whole stones in this harder
part of the chalk are not composed of these particles,
but there are confusedly thrown in among them some
broken parts of other substances, and in a few places
some globules of blood and small remains of other
juices. The second kind of chalky matter is less hard
and less white than the former, and is composed of
fragments or irregular parts of those oblong bodies
which compose the first or hardest kind, and these are
mixed among tough and clear matter, interspersed
with the small broken globules of blood discoverable
in the former, but in much greater quantity. The
third kind appears red to the naked eye; and, when
examined with glasses, is found to be a more tough
and clammy white matter, in which a great number
of globules of blood are interspersed; these give it the
red appearance it has.