Rouben Mamoulian's Dr. Jekyll & Mr. Hyde, Starring Fredric March

The film was based on the story of Dr. Jekyll, a famous young doctor, who experiments upon himself and, by drinking a potion, becomes an evil embodiment of himself. After a time, he realizes that his evil self, Mr. Hyde, returns automatically without the aid of the drug. After murdering a man, Dr. Jekyll fights to remain the good doctor, rather than the evil Mr. Hyde, and ends by killing himself with poison.