Francisco Goya Los Caprichose Plate 33 (To the Count Palantine) (1797) Etching.
"In all of the sciences their are charlatans who already know everything without having learned anything and yet have a remedy for every ill. One should not believe in what they say, and the intelligent person does not trust them. An educated person is moderate in his promises and keeps them – the Count Palantine does not keep any promises at all."
Marcellus Laroon The Cully Flaug’d (1680s) Engraving
Kinky fun in the art world.
http://www.bpi1700.org.uk/research/printOfTheMonth/december2007.html#fn01 - more information on this engraving and others like it.
Credit to my friend Anadilu for finding this. :)