Corvina reads the binding note out loud from the back of the book, in a flat voice, the way a doctor reads a diagnosis.

CorvinaInk is taken from skin that has been made to flush. Not cut. Not bled. Made to flush, which is a delicate way of saying what it means.

MalfoidIt means this room has been used for exactly this before and somebody wrote the instruction down so it could be done again.

CorvinaYes. And every head of this school has known it since 1770 and none of them ever had to do it.