Every morning, after his owners leave for work, Rusty the terrier makes a four-block commute of his own. He carries a ball. He will not be distracted, not by sleepy-eyed cats, heading home from their nightly forays, and not by fresh rabbit tracks visible in the dewy grass. No one will call out to him, for he has bitten, or tried to bite, nearly everyone in the neighborhood.

I am 5. My annual two summer weeks at my grandmother's house in rural North Carolina has stretched to eight weeks because I've been working my way through the standard childhood illnesses, mumps, measles and chickenpox.Each morning, I refuse to dress in the clothes my grandmother chooses for me and must stay in my room until I do. My grandmother sews the clothes, the bottoms some sort of shorts and skirt combination, with matching tops in various pastel plaids, closed by four huge buttons, suitable for little girls. I want to wear my jean shorts and T-shirts.The initial refusal periods lasted for hours. Later, maybe 15 minutes or so out of principle. None of the neighborhood kids will see me anyway. They're not allowed to visit since they'll likely get whatever I have.Of course I have another playmate who doesn't have those fears and visits every day. It's Rusty the terrier. Each morning, he scratches at the door of my grandmother's house and spends the day with me. We often play fetch with the ball, a game he loves.Eventually I work my way through recovery from mumps, measles and chickenpox. My parents come to visit and take me back to Pennsylvania.The morning after I leave, Rusty scratches on the door and my grandmother opens it. He checks every room in the house, and then goes back to the door and scratches to be let outside.He walks away, she always said, when she told the story year after year, as if he's lost his best friend in the world.She sees that he's dropped his ball by the door and calls out to him, rolls the ball down the walkway to him.Rusty stands and watches it until it stops rolling, then starts walking again. He never comes back.In the years to come, my grandmother tells the story of Rusty in a way that makes all the grown-ups laugh.She adds phrases like, "All he needed was a hobo stick with a bandanna tied on it," and then, with perfect timing, just as the laughter is dying down, "He never even tried to bite anybody again."But the story of Rusty always fills me with regret. Of courseI had no way to explain to a little terrier mix that I had to leave.I wish he could have known that I missed him, and that 50-plus years later I remember him still.I wish he could somehow know that because of him, always, I would have a place in my life for a dog.