Boris Karloff's character's name in the film is spelled John Ellman in close-ups of teletype and newspaper material in it, but it is misspelled John Elman in its credits.
When they lower the glass box over the "dead" John Ellman before he is resurrected, his right eye blinks.
When the two crooks shoot at John Ellman, they fire seven rounds from a revolver that shoots only six rounds.
Nancy calls Dr. Beaumont on the telephone to tell him that John Ellman has been shot, but she does not tell him where she is. Nevertheless, Dr. Beaumont shows up moments later in the graveyard and finds her there.