House of Dark Shadows

At Collinwood Estate, a gothic mansion on a hill overlooking the small costal Maine town of Collingsport, the troublesome Collins family handyman Willie Loomis (John Karlen), seeking to steal a fortune in family jewels, opens a hidden coffin in the Collins family crypt, releasing 175-year-old vampire Barnabas Collins (Jonathan Frid) from his 150-year confinement. Barnabas makes Willie his slave as his eyes and ears during the daylight hours. Barbabas' first victim is Daphne, the housekeeper, as she is preparing to leave for the night.The following night, Barnabas presents himself to the modern day Collins family whom include Roger (Louis Edmonds), his older sister Elizabeth (Joan Bennett), her teenage daughter Carolyn (Nancy Barrett), and their 12-year-old son David (David Henesy) as a "cousin from England." Barnabas moves into the "Old House" on the Collins estate, where the "first" Barnabas had lived. To thank his gracious hosts, Barnabas throws an elaborate costume ball.At the party, Barnabas becomes attracted to the family governess Maggie Evans (Kathryn Leigh Scott), who looks just like his long-lost love, Josette DuPree. When Carolyn, who has become one of the vampire's victims, threatens to reveal his secret out of jealousy, Barnabas kills her. Carolyn rises from the grave as one of the undead, and seeks out her former lover, Todd Jennings (Don Briscoe). Professor T. Eliot Stokes (Thayer David) uses the young man as bait for Carolyn, who is eventually trapped and staked by Stokes, aided by the Collinsport police.Meanwhile, a doctor, Julia Hoffman (Grayson Hall), has studied blood samples from the victims and begins to conclude that vampirism is real and that it may be a curable disease. She has accidentally discovered, while using a compact mirror, that Barnabas is the vampire (he naturally casts no reflection). She makes a pact with Barnabas and develops a serum to cure him of his blood lust.The cure works for a while, and Barnabas's courtship of Maggie proceeds. For a few weeks, Barbabas is able to walk in daylight for limited periods and does not feed on blood. He gets Maggie's boyfriend, artist Jeff Clark (Rodger Davis), out of the way by arranging a showing of the young man's paintings in nearby Boston. However, Julia, who has fallen in love with Barnabas, discovers his dalliance with Maggie. Insanely jealous, Julia gives Barnabas an overdose of the serum, with the result that he ages to his true 175 years. Barnabas angrily kills Julia, and restores his youth by biting Maggie. He flees with the young woman. Stokes and Roger Collins quickly research the family history of Barnabas in 1797, and Stokes is convinced that Barnabas intends to take Maggie as his bride.The search extends to St. Eustace, an island off the shore of Maine. Jeff discovers that both Stokes and Roger Collins have become vampires, and he has to destroy them both; Stokes with the silver bullets intended for Barnabas, and an arrow through the heart for Roger.Jeff tracks the vampire to an abandoned monastery, where Barnabas is planning to make Maggie his bride. Jeff attempts to shoot Barnabas with a crossbow, but Willie, who is also infatuated with Maggie, rushes over to the altar to stop Barnabas. The arrow that Jeff aims at the obsessed vampire hits Willie in the back. Barnabas pulls the crossbow bolt from Willie's back, then Barnabas takes Jeff under his hypnotic control, simultaneously dropping the crossbow bolt to the floor, next to Willie. As Barnabas is about to vampirize Maggie, Willie revives and plunges the wooden bolt into Barnabas's back; the vampire spins to see Willie, and in a rage, strangles the dying Loomis.Wounded, Barnabas' hypnotic control is broken, which allows Jeff to finish off Barnabas with the stake, which bursts through the vampire's chest, finally bringing an end to the undead existence of Barnabas Collins. With Barnabas dead, Maggie is no longer in a trance, and recognizes Jeff, who carries her in his arms, both briefly observing the bodies of Barnabas and Willie, before leaving the monastery.After the end credits roll, the seemingly dead Barnabas turns into a large bat and flies away, but this death-defying feat (since he was killed in the traditional manner only minutes before) goes unexplained.

Question: What does the doctor, Julia Hoffman, feel that she can cure?
Answer: Blood lust