Warm Plaster.
Take of gum plaster, one ounce; blistering plaster, two drachms. Melt them together over a gentle fire.
This plaster is useful in the sciatica and other fixed pains of the rheumatic kind: it ought, however, to be worn for some time, and to be renewed at least once a-week. If this is found to blister the part, which is sometimes the case, it must be made with a smaller proportion of the blistering plaster.
William Buchan
Domestic Medicine 2nd edition 1785