The third Boris Karloff "mad doctor" film is an interesting if surprisingly rather dull affair; the star is always worth watching, however, and his role here certainly offers him plenty to sink his teeth into: he starts the film as an old man about to be hanged for a mercy killing, is then rejuvenated through a serum he develops while in prison (the kindly warden having consented to Karloff continuing his experiments there until the time of his execution comes) and finally turns into a strangler (the unfortunate side-effect of the drug which contained the blood cells of a murderer)!
Though the supporting cast features several familiar faces, they're all somewhat underused: Evelyn Keyes and Bruce Bennett are certainly among the higher-prolife actors to fill the 'romantic interest' roles in this type of film, but they're just about the most thankless I've ever seen (especially Bennett who has barely 5 minutes of screen time)! Edward van Sloan's presence was especially welcome (having memorably faced-off with Karloff twice before) but, again, his prison doctor here is nowhere near as juicy as his iconic roles in Dracula (1931), FRANKENSTEIN (1931), THE MUMMY (1932) and DRACULA'S DAUGHTER (1936)! Pedro de Cordoba, on the other hand, is quite poignant as Karloff's pianist friend whose career is fading due to his advancing age; of course, Boris is willing to help him out in this regard, but his new-found and uncontrollable murderous instincts prevail! A measure of amusement is also gleaned from noticing the recurring presence of such actors as Roger Pryor, Don Beddoe and Charles Trowbridge in roles which were pretty much reprises of ones they had played in the earlier Columbia Karloffs!
On the debit side, the low budget especially shows here in the film's rather dismal sets - the other three of Karloff's serious horror efforts for Columbia made good use of the star's gadget-filled house (THE MAN THEY COULD NOT HANG [1939]), frozen underground lab (THE MAN WITH NINE LIVES [1940]) and Karloff's imposing cliff-top mansion (THE DEVIL COMMANDS [1941]); besides, the rather clinical experiments become repetitive and the film talky, which is further exacerbated by the regrettable fact that throughout there are few action/horror highlights per se.
As far as the film's DVD presentation goes, I found it to be disappointingly lackluster: while the print itself is adequate, there are no scene selections for any of the films in this set (which also proves to be the case with Universal's Karloff collection and the "Inner Sanctum" Set!) nor, for that matter, proper menu screens - have the studios become stingy or what?!
