For weeks, I've watched a little girl with lopsided pigtails come to ballet class. She wears a tiny white leotard and tights that sag on her small, 4 year old frame. Before each class, she says a tearful goodbye to her mother at the door and makes her way to the wooden barre. Although distraught at the separation, she remains absolutely obedient to the instructions of the teacher. Through weepy eyes, she skips across the floor, all while clutching a wadded up tissue in her fist. When her eyes become too misty, she dabs them while marching in rhythm to the music of The Nutcracker. Occasionally, an audible sob emerges, but she never strays from performing each exercise perfectly. Last week, the familiar scene unfolded with a slight change. Instead of a kiss goodbye, her mother stepped into the classroom holding a brightly colored dog.  "Now, where should we put Stuffy?" her mother asked. "Right here by the piano, so he can watch over you?" The little girl silent...