The Dr X of the title is Doctor Xavier, a name used by Marvel some thirty years later for the leader of the mutants known as the X-Men. This Dr Xavier leads a different bunch of outcasts – unhinged scientists, one of whom, the police are pretty sure, is a serial killer and cannibal. There is much use of early psychoanalytical tropes including Xavier’s theory that “strong mental repressions phobias, hidden in the darkest corners of the subconscious mind can be brought to the surface and made to register through certain reactions of the heart.” This idea, which was to become the polygraph or “lie detector” machine, was popularised later in the decade by William Moulton Marston, the creator of Wonder Woman, who published a book called The lie detector test in 1938. Maybe it was just the zeitgeist.

Anyway, the film is populated by kooky scientists, as well as Doctor X’s daughter, played by Faye Wray the year before she rose to great heights in King Kong, and a lovably slapstick journalist, Lee Taylor, who is working on the story of the serial murderer known as the “Moon Killer”, so called because the murders always happen on the full moon, a device widely used in fiction (and fact) as there is a widespread belief that the full moon causes people to become “lunatics” – a theory employed to the full in this story. Taylor sneaks into the morgue disguised as a corpse (there is a lot of dark humour in the film, with Taylor conversing with various dead bodies and even skeletons). He hears Xavier telling the police that the latest victim’s deltoid muscle is missing: the police observe that it was torn out. Dr X corrects them: “Gentlemen, it wasn’t torn. This is cannibalism!” The police are then permitted to tour the research centre in which the dedicated crazies in their various labs offer crazy anecdotes: one gratuitously has a heart in a jar, which has been kept alive for three years by electrolysis, and another has spent years in Africa researching cannibalism. In each lab, the police are convinced they have found the killer, but the stories get worse – two of the scientists were shipwrecked off Tahiti in a boat with another man, and, although they claimed he had died and they had thrown him overboard, it was suspected that they had, in fact, eaten him.

Dr X believes that one of his scientists was, in the past driven by “dire necessity” into cannibalism. “The memory of that act was hammered like a nail into the mind of that man”. Although he could conceal his madness from others, perhaps even from himself, Dr X can use his radio sensitivity machine to reveal the truth. The police allow Dr X to run his own tests with his prototype lie detector, but of course nothing goes smoothly, and the apparent perp (according to the machine) turns up dead. Later, when they look closer at the body, they find that it has been… Well, they don’t want to put it into words, and certainly not while Faye Wray is around. The real killer is busy making synthetic flesh, but not to eat (he is apparently into natural, whole foods). He needs flesh from humans, originally supplied by willing savages, for his experiments in creating faux flesh. “What difference did it make if a few people had to die?” he asks – a question oft repeated by the patients who are being mentored by Dr Hannibal Lecter in the TV series Hannibal. Now he’ll be able to “make a crippled world whole again”, a novel take on eugenics – build new people instead of breeding them.

Does that even count as cannibalism? Well, he is using human flesh, much as the medical cannibals of early modern Europe loved to do. He has learned his trade from cannibals, who, even in 1932, were assumed to make up the entire population of Africa. He has imported savagery from the Dark Continent to our peaceful, law-abiding shores, and isn’t that what we fear most?