Carrow broke the boy's arm. Judging by the bruising, I'd say he smashed it across the edge of his desk. It's healing now, of course, and was whole enough that the boy insisted on carrying out his regular tasks for me this morning.

I despair of it, Minerva. Carrow knows he can batter the boy with impunity--in fact, I'd wager he allows himself grosser violence--because he knows that I will heal the boy again, so he needn't even factor in the inconvenience of losing the boy's service to his injuries. I am simply a wheel in Carrow's machinery of torture. And yet, I can hardly refuse my role: to leave the boy suffering when I have the opportunity and means to heal him is not an option. Imagine if I were to send him away as broken as he arrived? Carrow would likely kill him for having become useless--to punish me for abdicating from his scheme.