In act 1, scene 1 of Arthur Miller's play about the Salem witch trials, The Crucible, Reverend Samuel Parris, Salem's minister for the past three years, says that he's sent for Rev. John Hale, a respected clergyman and reputed expert on witchcraft from the nearby village of Beverly. Reverend Parris sent for Reverend Hale to disprove that witchcraft—what Reverend Parris calls "unnatural causes"—had anything to do with his daughter's inability to wake up, for which the local doctor, Doctor Griggs, says there's no medical explanation.
In calling for Reverend Hale to come to Salem, Reverend Parris is concerned not only for his daughter's condition but for his own standing in the community. Reverend Parris is not particularly well-liked, and he's afraid that the people of Salem might use Betty's condition against him, particularly if it's found that Betty's inability to wake up is due to "unnatural causes."
Reverend Hale arrives later in the scene, and he interviews a number of Salem's townspeople, including Reverend Parris's seventeen-year-old niece, Abigail Williams, who confirms Reverend Parris's worst fear, which Reverend Hale supports rather than dispels.
It was Reverend Parris himself who brought Abigail to Reverend Hale's attention by mentioning that he saw "my niece and ten or twelve other girls, dancing in the forest last night." In order to avoid punishment for her dancing in the woods, Abigail casts suspicion of witchcraft and devil worship on Tituba, Reverend Parris's forty-year-old house slave from Barbados.
Abigail's "proof" of Tituba's witchcraft is that Tituba made Abigail drink blood, which Tituba confirmed was chicken blood after Mrs. Putnam interjected that the blood might be the blood of her dead children.
Reverend Hale asks Tituba if she's sent her spirit out on Betty, which prompts Abigail to claim, "She sends her spirit on me in church" and makes her laugh during prayers. Reverend Parris confirms that Abigail often laughs during prayers, which essentially "proves" Abigail's accusation.
Abigail raises the seriousness of her accusations against Tituba by claiming, "She comes to me every night to go and drink blood" and saying that "she's always making me dream corruptions." Abigail says that when she sleeps she hears Tituba laughing and "singing her Barbados songs," which is sufficient "proof" for Reverend Hale to command Tituba to wake Betty from her stupor.
Having set the wheels of suspicion against Tituba in motion, Abigail simply waits for her next opportunity to cast suspicion on others and away from herself. It's not long before Tituba tries to save herself by accusing others of witchcraft, to which Abigail adds her voice and increases the level of hysteria, which results in the fragmentation of the Salem community and the death of innocent Salem townspeople.