A drachm of Peruvian bark, twenty grains of calcined Magnesia, and four
ounces of distilled water being rubbed together during fifteen minutes,
the filtered infusion resembled in appearance the simple tincture
of bark, and had an intensely bitter taste, but was not strongly
impregnated with the peculiar aroma of the bark.
Thus then we have an easy and very elegant method of preparing
aqueous tinctures from the gum resins, and administering them in a
more convenient form and in larger doses than could be done when
dissolved in a spirituous menstruum; and much more agreeably than in
the half-dissolved state to which they are reduced by the aid of egg
or gum arabic. The Magnesia does not impart any thing to them, whereas
the lime will seldom be so saturated with air but that some part of
it will remain soluble in the water: and as they may be given diluted
to whatever degree the prescriber chuses, considerable advantages may
be expected therefrom, it being probable that they will be better
enabled to pervade the very small vessels; and the heating properties
of the balsams be more effectually obviated than by any other mode of
preparation.
Indeed, tinctures prepared by the above method, are not calculated for
officinal compositions, but for extemporaneous prescription; as most of
them, except camphor, deposite a sediment when they have been kept a
week or two.