A Diuretic Foment.
Take roots of Smalage 4 ounces; roots of Fennel, Linseed, each 2 ounces; Herbs Pellitory of the Wall, Mallows, Arsmart, Camomile flowers, each 2 handfuls; boil in Water 3 quarts to 2 quarts; in the strain'd dissolve crude Salt Armoniac ( or if you cannot get it, Salt Prunel) half an ounce; common Soap 2 ounces, mix.
Its used with laudable Success, in the cruellest Fits of Stone in the Bladder, accompanied with most lamentable torture and suppression of Urine. But it doth not operate (as vulgarly believ'd) because it consists of Ingredients that are properly Diuretic, and endow'd with a Specific gift of expelling, but partly , because it relaxes and recreates (by its soft Foment and kindly Warmth) the Muscles of the Abdomen and Bladder, which the pain and afflux of Humors, had rendered tense and rigid; and partly because (by mildly pricking them up as it 'twere, and stimulating) it provokes then to fall on a fresh upon their usual Business of Constriction.
Thomas Fuller
Pharmacopeia Extemporanea 1710