A lock hospital was an establishment that specialised in treating sexually transmitted diseases. They operated in Britain and its colonies and territories from the 18th century to the 20th.
Cartoon showing inmates of a lock hospital, 1802. The man at left is undergoing paracentesis (draining of fluid from the abdomen). In the centre, one patient reads handbills for quack medicines. At right, a prosperous and smug apothecary (pharmacist) rides in a coach with footmen; his family motto is Memento mori, "remember you shall die."