If I went for snark more often in my reviews, I might say that "The Black Sleep" will put *you* into a black sleep. But, in truth, it's not *that* bad. It's just somewhat disappointing, given the gathering of some of the shining lights of the horror genre. This is really more of a period drama (with precious little period recreation - this is mostly shot in interiors) with touches of horror. Its first three quarters are somewhat dull, and talky, and most unfortunate of all, NOT very atmospheric.
The story mostly centers around the activities of a deranged doctor, Sir Joel Cadman (Basil Rathbone) who saves a former student, Gordon Ramsey (!) (Herbert Rudley) from the hangman. This he does with the assistance of a drug, the "Black Sleep" of the title, that can make people appear to be dead. Sir Joel intends to have Ramsey assist him in his radical research into the human brain. Ramsey meets such characters as Daphne (Phyllis Stanley), Sir Joels' loyal nurse, two mutes (Lon Chaney Jr. and Bela Lugosi), and the very fetching young Laurie Monroe (Patricia Blair), while an annoying, talkative gypsy named Odo (Akim Tamiroff) provides Sir Joel with unwilling test subjects.
"The Black Sleep" is saved, to a degree, by its final quarter, which is good fun, as more characters come crawling out of the woodwork. Among them is a hirsute John Carradine. Don't be fooled; despite his prominent billing, his is little more than a cameo role. The same goes for the hulking Swedish wrestler Tor Johnson, who doesn't show up for a long time. The reasonably likable Rudley does a decent job of carrying the story. He's a good man who claims to be innocent of a murder charge, and there's no reason to doubt him. He's also the moral centre, scoffing at the insanity perpetrated by Sir Joel. Mr. Rathbone is marvelous; his performance does ultimately transcend the material. But performers like Carradine, Lugosi, and Chaney end up rather under utilized.
Directed without much style by Reginald Le Borg ("Weird Woman", "Diary of a Madman"), but the score by the talented Les Baxter is definitely worth a listen.
Six out of 10.