Ornate blue gilt earthenware jar made by Alcock at Burslem, Stoke-on-Trent, Staffordshire. Part of a set of three leech jars. The practice of bleeding, or bloodletting, was intended to drain 'poisons' or excess blood from the body in order to restore the balance of the humours. Bleeding was a popular therapy in the Middle Ages, and continued to be practised as late as the 19th century.
© Science Museum / Science & Society Picture Library