“If, hypothetically, a student came to me in the immediate aftermath of an accident, I could provide them with a potion that would prevent fetal implantation or induce a menstrual period. Either one would cause about thirty minutes of heavy bleeding followed by a bit of fatigue. If, hypothetically, a student came to me in the less-immediate aftermath of an accident—say, perhaps, anything earlier than nine weeks in—I could give her a pair of potions. She’d take the first one right away, and then spend the next three days bleeding and drinking the second one.”