Why has Reverend Parris sent for a doctor as the play begins?

Reverend Parris's daughter, Betty, will not wake up. He sends for the doctor because he wants to find out what's wrong with her; he is hoping she is just ill. He also sends for Reverend Hale because the community is talking of witchcraft, and he wants to disprove it. Ironically, the arrival of Hale begins the witch hunt in earnest.