Doctor from Seven Dials

In 1840s London, Dr. Thomas Bolton (Boris Karloff) develops an opium-based anesthetic to relieve the suffering of surgery patients, fighting for its use and testing it on himself as a guinea pig, but becomes addicted to his chemical experiments. To secure chemicals for his work and addiction he falls in with a den of murderers who use his signature to sell cadavers to the local hospital, his efforts blocked by a ruthless killer (Christopher Lee).