as Dr. Janos Rukh
as Dr. Felix Benet
as Ronald Drake
as Diana Rukh
as Mother Rukh
as Lady Arabella Stevens
as Sir Francis Stevens
as Monsieur Noyer
as Professor Meiklejohn
as Chief of the Surete
as Mme. LeGrand (uncredited)
as Papa LaCosta (uncredited)
as Briggs (uncredited)
as Celeste (uncredited)
as Gendarme (uncredited)