Revealing mistake: There is a large painted hanging cloth backdrop of clouds in the mountain scenes near the end of the film. Vertical streaks can be seen in the backdrop that are the pleats in the fabric. These streaks really stand out in the restored versions of the film.
Revealing mistake: When Dr. Waldman gives the monster an injection and the Monster is trying to get the torch out of Henry Frankenstein's hands, if you look closely, Boris Karloff's (the Monster) make-up begins to smoke when he is hit by the torch. (00:37:35)
Answer: By the third film, the original "Baron Frankenstein," played by Frederick Kerr is supposed to have died. Therefore, his son Henry had inherited the title of "Baron Frankenstein," and as part of Germanic aristocratic inheritance this automatically places a "von" between the Christian name and Surname of the holder. This in turn has happened when Henry died and Wolf took up the Baronetcy.
David Mercier