Dr. Pretorius: We shall drink to our partnership. Do you like gin? It is my only weakness.
Mary Shelley: It's a perfect night for mystery and horror. The air itself is filled with monsters.
The Monster: We belong dead!
Dr. Pretorius: To a new world of gods and monsters!
The Monster: Alone: bad. Friend: good!
Editing after previews resulted in the loss of a subplot in which Karl imitates the Monster's murderous modus operandi to eliminate his miserly aunt and uncle and direct the blame away from himself.
The "body count" in the original cut was 21. This was trimmed to 10 after pressure from the censors.
When the castle is self-destructing, the Doctor can be seen against the far wall. Yet he is next seen outside in the arms of his beloved, watching the explosions. There were two endings originally: the first had Doctor Frankenstein dying within the castle and this was filmed. But the producers judged this a bit harsh and wanted a happy ending, so they shot the extra footage (too expensive to re-film the explosions).
Shot in 46 days at a cost of approximately $400,000. Boris Karloff sweated off 20 pounds labouring in the hot costume and make-up.
Not long before filming began, Colin Clive broke a leg in a horse riding accident. Consequently, most of Dr. Frankenstein's scenes were shot with him sitting.
DVD Easter Eggs: (Hidden So You Don't See Anything You Don't Want To See)