The "glass heart" machine used to revive John Ellman in the film was said to be "nearly a prefect replica" of an actual perfusion pump - a device designed to keep organs alive outside an organism's body - which had been built by Charles Lindbergh when the legendary pilot and engineer was working with a Nobel-winning scientist at New York's Rockefeller Institute research labs in the mid-1930s.
It has been stated in later years by film historians that director Michael Curtiz made this film as quickly as possible so he could proceed to make other, more important films.
The accident scene in the film was shot in Griffith Park.
Filming began on November 23, 1935 (Boris Karloff's 48th birthday) and lasted 18 days, finishing on December 23, 1935.
Boris Karloff's character in this film was originally conceived as being named "Dopey" Ellman and was originally both a drug addict and an alcoholic.