“How do we seize the past? Can we ever do so? When I was a medical student some pranksters at the end-of-the-term dance released into the hall a piglet which had been smeared with grease. It squirmed between legs, evaded capture, squealed a lot. People fell over trying to grasp it, and were made to look ridiculous in the process. The past often seems to behave like that piglet.”