The film contains a couple of clever in-jokes for Holmes aficionados in the form of references to famous unrecorded cases for the Great Detective: at one point Watson begins to recite the tale of The Giant Rat of Sumatra (mentioned in Conan Doyle's "The Adventure of the Sussex Vampire"); whilst the action takes place aboard the S.S. Friesland (from Conan Doyle's "The Adventure of the Norwood Builder", and alluded to as "a Dutch-American liner" in his Professor Challenger book "The Lost World", though here it has links to Malmö in Sweden). The film also borrows some characters and events from "The Adventure of the Red Circle."
This is one of a few Sherlock Holmes movies where the set for Baker Street wasn't used.
The twelfth of fourteen films based on Arthur Conan Doyle's fictional consulting detective Sherlock Holmes starring Basil Rathbone as Sherlock Holmes and Nigel Bruce as Doctor Watson.
Mrs. Hudson doesn't make an appearance in this film.
This is the only Holmes film that you see Holmes wearing pyjamas.