Columbia's 'Mad Scientist' quintet was supervised by line producer Wallace MacDonald, the initial three all scripted by Karl Brown and directed by Nick Grinde, the template set from the start, Boris Karloff a dedicated researcher whose experiments often skirt into illegality, hoping to achieve something positive for mankind even if it means sacrificing a few lives (the actor's previous Columbia SON OF SHOCK titles included "Behind the Mask" and "The Black Room"). 1939's "The Man They Could Not Hang" actually kicks off exactly that way, an artificial heart made of glass designed to pump blood through tubes in an attempt to revive the actual human heart and restore life to a body that has been scientifically put to death to more easily perform surgery without the pressure of a race against time (commonly known today as open heart surgery, the film gets it right). His assistant Lang (Byron Foulger) is present along with a willing test subject (Stanley Brown) eager to do a great benefit for humanity, his complete trust in Karloff's Dr. Henryk Savaard undone by an unthinking fiancée (Ann Doran), her subsequent summoning of the police assuring the young man's demise. Pleas for one hour to save the boy's life fall upon deaf ears, a trumped up trial only a pretense for disbelieving medical authorities to put a stop to Savaard's incredible theories, the title incorrect for they DO actually hang him ("Before I Hang" should have sported this title, this one redubbed "After I Hang!"). Lang claims the corpse and revives Savaard, after which six of his jurors mysteriously suffer suicide by hanging, reporter 'Scoop' Foley (Robert Wilcox) joining the remaining jurors at the supposedly deserted Savaard home to learn the truth. Secure in the knowledge that no one would ever suspect a man legally dead, the now insane medico is determined to gain revenge on the short sighted authorities who denied him justice ("they killed the man I was"). The law of diminishing returns works against the four follow ups, and it's tough to imagine Karloff topping his performance here, from sympathetic entreaties for techniques to preserve life to embittered angel of death, a devoted dispenser of retribution. Interestingly, his Warners debut in "The Walking Dead" found him an innocent man electrocuted for a murder he didn't commit, restored to life by Edmund Gwenn, only his resurrection is a spiritual one, his enemies driven to destroy themselves through their own guilt.