Bruise a sufficient quantity of isinglass, and let it soak for
twenty-four hours in a little warm water; expose it to heat over the
fire, to dissipate the greater part of the water, and supply its
place by colourless brandy, which will mix the gelatine of the glue.
Strain the whole through a piece of open linen: on cooling, it will
form a trembling jelly.
Now extend a piece of black silk on a wooden frame, and fix it in
that position by means of tacks, or pack-thread. Then, with a brush
made of badger’s hair, apply the glue, after it has been exposed
to a gentle heat, to render it liquid. When this stratum is dry,
which will soon be the case, apply a second, and then a third, if
necessary, to give the plaster a certain thickness; as soon as the
whole is dry, cover it with two or three strata of a strong tincture
of balsam of Tolu.
This is the real English court plaster: it is pliable, and never
breaks, characters which distinguish it from so many other
preparations sold under the same name.
_Application._
This plaster is generally used to cover slight abrasions and
excoriations of the skin. When used for small cuts, from sharp
instruments, bring the lips of the wound together, and lay over it
a piece of goldbeater’s skin; then fix this by means of a piece of
court plaster. The wound will generally heal without further trouble.