Fludd's system of health. 17th century engraving depicting the healthy man (centre) surrounded by archangels within the fortress of the body. Plagues are sent from demonic figures from the four corners of the world: from the north comes melancholy, from the east comes disease of the phlegm, from the south comes sanguine diseases and from the west choleric. The man is further empowered to defend against disease by the power of the divine (top). This engraving comes from Medicina Catholica by Robert Fludd, printed at Frankfurt in 1629.