Doctor Butler's Preservative against the Plague

Take Wood Sorrel, and pick it from the stalk, and pound it very well in a stone Mortar; then take to every pound of beaten Sorrel a pound of Sugar finely beaten, and two ounces of Mithridate, beat them very well together, and put them in pots for your use; take every morning before and after the Infection for some time together of this Conserve, as much as a Walnut.

The Queens Cabinet Opened: Or, The Pearle of Practice. Accurate, Physical and Chirurgical Receipts, Nathaniel Brooke