An itinerant surgeon extracting stones from a man's head; symbolising the expulsion of 'folly' (insanity) Line engraving by L. van Leyden, 1524.

The images of a surgeon (often itinerant) making an incision in a patient's head in order to extract 'stones' (implying madness in the individual) do not represent an actual operation, but are allegorical scenes refering to the subduction of 'folly' (madness) from the body. See further: W. Schupbach, A new look at The cure of folly, Medical history, 1978, vol. 22, pp. 267-281