John A. Davis mailed a Christmas card to his brother in December 1942. Nearly 55 years later it showed up at a post office in Tinley Park, Illinois. Davis had long ago figured the card, sent from Jackson, Miss., to Maryville, Tenn., got lost. The long-lost card raised eyebrows at the Tinley Park post office, and Davis' family learned about it through a newspaper account. The supervisor had sent the card on to Maryville but got it back when Davis contacted him. "There is a lot of nostalgia in this thing. I'm sorry that my brother died a couple years ago. He would have gotten a kick out of it," Davis, a retired Chicago area businessman, said. Davis is wondering about the mysterious ways of the Postal Service, as well as where the card was for more than 50 years. The envelope's lone postmark …