panacea or medicine which cures the leprous metals of their corruption and transmutes them into gold is the philosopher’s stone or elixir. The Golden Tract said of the Stone: ‘it is a subtle spirit which tinges bodies, and cleanses them of their leaprous infirmities’
This passage establishes the leper as the central alchemical metaphor for corrupt matter requiring the philosopher’s stone’s purifying and transmuting action, with Naaman the leper as the governing biblical proof-text.
, A Dictionary of Alchemical Imagery, 1998thesis