_Take Spanish flies eight ounces finely powdered, common drawing
plaister one pound, melt the plaister and sprinkle the powdered Spanish
flies till all is well incorporated, then make it into rolls according
to art._
This is intended for rising blisters. In regard to the use of this, I
have only to observe, that it should be made use of only, when the
greatest necessity requires it; that is, in bringing on a crisis of a
fever, which I shall point out in its proper place. At present I shall
only speak of its application. Whatever place is intended to be
blistered, either the neck, between the shoulders, or the calf of the
leg, let the place first be cleaned with a little vinegar, and rubb’d
till it becomes red, then let the blistering plaister, the bigness of
the palm of the hand, pretty thickly spread, (best upon leather) be laid
on the part, and remain there for about twelve hours, and be tied on,
that it may not shift: at that time the blister will rise; let it be cut
to let the water out, (but care should be taken not to pull off the
skin, as is frequently practiced) dress it with _Turner’s Cerate_,
spread upon a thin rag, (or what is still better, dry lint) and let that
dressing be shifted once every twelve hours, till all is healed up.