Mrs. Darling first heard of Peter when she was tidying up her children's minds. It is the nightly custom of every good mother after her children are asleep to rummage in their minds and put things straight for next morning, repacking into their proper places the many articles that have wandered during the day. If you could keep awake (but of course you can't) you would see your own mother doing this, and you would find it very interesting to watch her. It is quite like tidying up drawers. You would see her on her knees, I expect, lingering humorously over some of your contents, wondering where on earth you had picked this thing up, making discoveries sweet and not so sweet, pressing this to her cheek as if it were as nice as a kitten, and hurriedly stowing that out of sight.