Hieronymus Bosch. The Stone Operation. 1475-1480. Oil on panel. Museo del Prado, Madrid, Spain.

The Stone Operation. There was an old Dutch saying for a person of odd behavior that he had 'a stone in the head'. Trading on credulity of simple people, charlatans would offer to extract stones. They always found patients among those with headaches. The 'surgeon' would then tie his patient safely to a bench, make a small cut and under cries, moans and groans of the victim produce a pebble or two covered with blood. These 'surgeons' were a popular object of satire in the 17th century.