as Sherlock Holmes

as Dr. John Watson

as Lydia Marlowe

as Professor James Moriarty

as Sir George Fenwick

as Inspector Gregson

as Maude Fenwick

as Dr. Onslow

as Dr. Simnell

as Corporal Williams

as Crandon

as Mrs. Hudson

as Waring the Mesmerist (uncredited)

as Shoelace Vendor Henchman (uncredited)

as Carter the Hypnotized Subject (uncredited)

as Bar Patron (seen in mirror) (uncredited)

as 4th Victim (uncredited)

as Commissioner of the CID (uncredited)

as Fenwick's Butler Norris (uncredited)

as Short-Tempered Officer Closing Window (uncredited)

as Member of Mesmer Club (uncredited)

as Pembrook House Waiter (uncredited)