Sir K. Digby (1603-1665), English courtier and diplomat, was a highly reputed natural philosopher but also regarded as an eccentric partly because of his interests in the occult. One of his pursuits was the concept of the powder of sympathy, a form of sympathetic medicine consisting vitriol "whereby a remedy was applied to the weapon that had caused a wound with the aim of healing the injury it had made. Weapon salve was a preparation, again applied to the weapon, but based on material from the wounded patient rather than on any remedy for the wound"  Fascinating exploration of the theories of sympathies and occult medical practice.
 
Digby, K. - Theatrum sympatheticum, in quo sympathiae actiones variae, singulares & admirandae tàm macro-quàm microcosmicae exhibentur, & mechanicè, physicè, mathematicè, chimicè & medicè, occasione pulveris sympathetici, ita quidem elucidantur, utillarum agendi vis & modus, sine qualitatum occultarum, animaeve mundi, aut spiritus astralis magnive magnalis, vel aliorum commentariorum subsidio ad oculum pateat. Opusculum lectu jucundum & utilissimum; Digbaei, Papinii, Helmontii, aliorumque recentiorum scriptorum prolata exhibens & trutinans, atque ipsius pulveris sympathetici germanam & optimam descriptionem simul exponens. Editio altera, priori emendatior. Amsterdam, Thomae Fontani, 1661. 6 Bl., 259 S.  12mo  18-cent. Hleather.   (spine slightly damaged, inside fine)