Werewolf of London (1935)

Wilfred Glendon is a wealthy and world-renowned English botanist who journeys to Tibet in search of the extremely rare selenotropic plant known as mariphasa lupine lumina. While there, he is attacked and bitten by a creature later revealed to be a werewolf, although he succeeds in acquiring a specimen of the mariphasa. Once back home in London he is approached by a fellow botanist, Dr. Yogami, who claims to have met him in Tibet while also seeking the mariphasa. Yogami warns Glendon that the bite of a werewolf would cause him to become a werewolf as well, adding that the mariphasa is a temporary antidote for the disease.

Glendon does not believe the mysterious Yogami. That is, not until he begins to experience the first pangs of lycanthropy, first when his hand grows fur beneath the rays of his moon lamp (which he is using in an effort to entice the mariphasa to bloom), and later that night during the first full moon. The first time, Glendon is able to use a blossom from the mariphasa to stop his transformation. His wife Lisa is away at her aunt Ettie’s party with her friend, former childhood sweetheart Paul Ames, allowing the swiftly transforming Glendon to make his way unhindered to his at-home laboratory, in the hopes of acquiring the mariphasa’s flowers to quell his lycanthropy a second time.