Accompanying - of all things - a treatise on the tapeworm, we find:
"Dionis' edition of Sir Kenelm Digby's account of the "Powder of Sympathy", an alchemical preparation purported to cure at a distance. Made from dried green vitriol, this was a variant of the well-known Paracelsian 'weapon salve' which cured wounds by being applied, not to the patient, but to the offending weapon. It is a measure of the endurance of belief in this cure that Dionis entered into a contemporary dispute concerning its use and provides a recipe for it. Pp. 65-266 here are occupied by Dionis's introduction and by Digby's text, first published in 1658."