Sir Kenelm Digby (1603–55), diplomat and natural philosopher, claimed a “powder of sympathy” could cure wounds at a distance — and his treatise sold well enough to run to twenty-nine editions in five languages. This Public Domain Review essay (text by Hunter Dukes) uses the 1669 edition to explore the early-modern line where sympathetic magic shaded into mechanistic science.

The origin story is likely contrived, but wonderful:

  • In 1624 the writer James Howell tried to break up a duel and was cut to the bone on both hands; King James’ surgeons proved useless
  • Digby soaked Howell’s bloodied garter in a basin of vitriol (ferrous sulfate) — the patient felt cool relief, and his palms burned when Digby later dried the garter by the fire
  • Re-submerged, the wounds healed; Digby said he learned the powder from a Carmelite friar in Florence who had conveniently retired to Persia, leaving Digby the only European who knew its value

The mechanism was “the remembrance of bodies”:

  • Things connected or similar — sharing origin, weight, density, or figure — could act on each other at a distance; hence carrying a toad during plague, since the venomous creature absorbs “the poison of a plague sore”
  • It was a version of the “weapons salve”: heal the wound by applying salve to the offending blade, not the victim
  • Per scholar Elizabeth Hedrick, Digby’s importance is that he explained occult phenomena “in more or less mechanistic terms” — atoms and corpuscles, with no recourse to demons and spirits

The best part is the satire it inspired. An anonymous 1688 pamphlet proposed keeping wounded dogs aboard ships with blood-soaked rags back in London: dip the rags in sympathetic powder each day at noon, and a ship’s longitude could be read from the sudden calm of maimed hounds. Parliament’s Longitude Act of 1714 — born of centuries of shipwrecks and imperial losses — offered a real prize for the problem.

A reminder that the boundary between magic and mechanism was never clean: Digby’s posthumous recipe book, The Closet of the Eminently Learned Sir Kenelme Digbie Kt. Opened (1669), printed the powder’s recipe beside instructions for Hotchpot and Humble Pyes.