3-057-432 - Heritage Art/Heritage Images

Circular zodiacal lunar scheme, 1486. Illustration from a surgeon's manual showing an adjustable horoscope-dial to set the position of the Sun. The medieval practice of astrological medicine decreed that the dominant influence on the balance of the four humours came from the heavens, and activities such as bleeding must not be undertaken unless the planets were in favourable positions. This dial would have calculated whether it was safe to carry out medical procedures according to the position of the planets. Additions made before 1768. From the Guild Book of the Barber Surgeons.