*. This needs some sorting out.
*. In the first place, this isn’t a sequel to Doctor X. It doesn’t have any of the same characters, though it does have a couple of the same character types, like the mad scientist and the wisecracking reporter. It doesn’t make use of “synthetic flesh” (opting insted for “synthetic blood”). It doesn’t follow up any of the events of the earlier film.
*. In Doctor X it’s not clear who the title is referring to: Doctor Xavier (never referred to as Doctor X), or just a generic suspect in the murder plot. In this movie there is a completely different Doctor Xavier (Humphrey Bogart’s character, whose first name is Maurice in the film but Marshall in the credits). Bogart’s Doctor Xavier is identified as Quesne (rhymes with “Cain,” get it?), and since he clearly isn’t Lionel Atwil’s Doctor Xavier, the title must be referring to Bogart’s “return” from the dead.
*. Bogart’s Dr. Xavier was executed for conducting an experiment to see how long he could starve a child before it died. Which, leaving aside any ethical questions, doesn’t sound like a very brilliant experiment. Nevertheless, Doctor Flegg thinks he was a genius and that his execution made him a “martyr to science.”
*. For all his grotesque appearance and evil history, Bogart makes Quesne somewhat sympathetic. Like Frankenstein’s monster, he didn’t ask to be brought back to life, and he seems at times genuinely down about what he has to do to stay alive. Note his pained expression in the window as he listens to Flegg give him up. How can you not feel sorry for him?
*. Originally it was planned as a sequel: in Technicolor, directed by Michael Curtiz again, and starring Boris Karloff and Bela Lugosi (as Quesne and Flegg respectively). Then it was downgraded, considerably.
*. Today we have a system of four blood types (A, B, AB, and O). In 1939 was there a system of four blood types that were just given numbers? I haven’t been able to find out. Were the producers here just making this part up?
*. When asked on the commentary if he researched any of the scientific details for the film, director Vincent Sherman laughs and says the prop man who dressed the lab set took care of that.
*. Sherman was 99 when he did the commentary, but sounds decades younger. He refers to the film as a “cornball” story that was made “for kids.”
*. Medical vampires are always a little more unnerving than the fanged variety. Having teeth in your neck is one thing, but a needle in your arm and some tubing draining your blood away is something else. And this is a trope with a long history in horror films. The mad doctor in Dreyer’s Vampyr, for example, has his own creepy transfusion kit.
*. That’s an awfully obliging cab driver Quesne has for the final chase. Is he a confederate? It’s not clear, but then the whole ending seems awkwardly jammed on.
*. This is a very minor, and very clunky, B-picture from Warner Brothers. Its only interest today is in Bogart’s one-off appearance in a horror film. It’s not a film that’s necessary to see once, and you’ll probably not want to see it again.