Boris Karloff
Dr. Janos Rukh
Acting
Bela Lugosi
Dr. Felix Benet
Acting
Frank Lawton
Ronald Drake
Acting
Frances Drake
Diana Rukh
Acting
Violet Kemble Cooper
Mother Rukh
Acting
Beulah Bondi
Lady Arabella Stevens
Acting
Walter Kingsford
Sir Francis Stevens
Acting
Paul Weigel
Monsieur Noyer
Acting
Frank Reicher
Professor Meiklejohn
Acting
Georges Renavent
Chief of the Surete
Acting
May Beatty
Mme. LeGrand (uncredited)
Acting
Paul McAllister
Papa LaCosta (uncredited)
Acting
Nydia Westman
Briggs (uncredited)
Acting
Ynez Seabury
Celeste (uncredited)
Acting
Robert Graves
Gendarme (uncredited)
Acting