I spoke to Lupin about Potter's recent insomnia, and he agreed to speak with him.(Note to self: Added chaparral and suffered a great joy in watching Lupin grimace. He appears to be suffering no ill effects from the new ingredient, so I will keep an eye on him through the next full moon before considering another addition.)
As a result, Potter stopped walking the halls for several days--but to my disgust, he has begun once again. Last night, I asked what he was searching for.
He didn't answer.
I didn't bother asking again.