Lambert Hillyer Director Boris Karloff Dr. Janos Rukh Actor Bela Lugosi Dr. Felix Benet Actor Frances Drake Diane Rukh Actor Frank Lawton Ronald Drake Actor Violet Kemble Cooper Mother Rukh Actor Walter Kingsford Sir Francis Stevens Actor Beulah Bondi Lady Arabella Stevens Actor Frank Reicher Professor Meiklejohn Actor Paul Weigel Monsieur Noyer Actor Georges Renavent Chief of the Surete Actor John Colton Screenwriter Edmund Grainger Producer Fred S. Meyer Executive Producer Franz Waxman Original Music George Robinson Cinematographer Bernard W. Burton Film Editing Albert D'Agostino Art Director Brymer Costume Design