Black Friday is a peculiar mixture of gangster film and Dr Jekyll and Mr Hyde (wherein a brain transplant serves in place of a personality-transforming potion). Alas, Kurt Siodmak never makes it clear what is going on if Boris Karloff simply transplanted Red Cannons brain into the professors body, why is there such a problem getting Ridgess professor to recall Cannons memories? Why for that matter does Cannons brain possess the professors memories at all if the professors original brain has been removed? In the latter half of the film, the brain transplant aspect drops out almost altogether (the same structural problem that Donovans Brain also had) and the film becomes a routine mobster melodrama about a gangster eliminating his old gang and finding the loot.
On the plus side, Black Friday is slightly better directed than most other B movie mad scientist efforts of the era, with director Arthur Lubin, who also made the Claude Rains Phantom of the Opera (1943), making occasionally effective use of shadow contrast. There is one particularly good shot where we see the transformation between professor and gangster, where Stanley Ridges puts his head in his hands as the mousy professor and then suddenly brings his face up as a tough guy. (It is rather amusing to note that the transformation of personalities between professor and gangster also manages to somehow correct the professors eyesight, with he no longer needing glasses, and causes his hair to become slicked back every time). In fact, it is a better delineation of personality change than the one that occurred in the Spencer Tracy Dr Jekyll and Mr Hyde (1941) around the same time.
Screenwriter Curt Siodmak was a German native who had worked as a novelist and began writing scripts in Germany with the science-fiction film F.P.1 Does Not Answer (1932). Siodmak and his brother Robert fled to the US with the rise of the Nazis. Robert Siodmak later became a director known for film noir thrillers such as The Spiral Staircase (1946), Son of Dracula (1943), and The Crimson Pirate (1952). Curt Siodmaks genre scripts include Trans-Atlantic Tunnel (1935), The Ape (1940), The Invisible Man Returns (1940), The Invisible Woman (1940), The Wolf Man (1941), Invisible Agent (1942), Frankenstein Meets the Wolf Man (1943), I Walked with a Zombie (1943), Son of Dracula (1943), The Climax (1944), House of Frankenstein (1944), The Beast with Five Fingers (1946), Tarzans Magic Fountain (1949), Riders to the Stars (1954), Creature with the Atom Brain (1955) and Earth Vs the Flying Saucers (1956). He also directed/wrote several films with Bride of the Gorilla (1951), The Magnetic Monster (1953), Curucu, Beast of the Amazon (1956) and Love Slaves of the Amazon (1957). Siodmak also wrote the classic novel Donovans Brain (1942) about a millionaires disembodied brain that ends up mentally controlling the scientist that removed it, which has been thrice filmed as The Lady and the Monster (1944), Donovans Brain (1953) and Vengeance/The Brain (1962). Siodmaks lesser known follow-up Hausers Memory (1968) about transplanted memories was also filmed as the tv movie Hausers Memory (1970).
Arthur Lubin was a prolific director who made some 70s films between the 1930s and 1950s. His other films of genre note include:- the Abbott and Costello film Hold That Ghost (1941); the Claude Rains Phantom of the Opera (1943); Ali Baba and the Forty Thieves (1944); the fantasy Night in Paradise (1946); the talking mule film Francis (1950) and sequels Francis Goes to the Races (1951), Francis Goes to West Point (1952), Francis Covers the Big Town (1953), Francis Joins the WACS (1954), Francis in the Navy (1955) and Francis in the Haunted House (1956); the comedy It Grows on Trees (1952) about trees that grow money; The Thief of Bagdad (1961); and The Incredible Mr Limpet (1964) about a man who turns into a porpoise.
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