At some point in her early puppyhood, Tilda got hold of an ice cube, and thought it was pretty great. We gave her one whenever we opened the freezer, and now she comes running whenever she hears us open the door. I toss the cube in the air and she leaps for it with the same glee and abandon shown by cartoon dogs who have stolen a length of sausage links from the butcher. Then she takes it into the living room and leaves it to melt on the carpet.