Leper ward. Engraving of the main leprosy ward of a 16th century hospital. The ward is clean, light and the patients each have their own beds. The physicians on the ward are cleansing sores. The man at centre is carrying a bowl with a razor blade in it; bleeding the patients was an attempt to treat the disease. Leprosy is caused by the bacillus Mycobacterium leprae and affects the nervous system, skin and mucous membranes. The loss of feeling it causes allows secondary infections to set in and disfigure the sufferer. Illustration of the ward at Valetta in 1586; this was run by the Knights of Saint John of Jerusalem, also known as the Hospitallers.