Jack London once said that he would "rather be ashes than dust." The distinction between the two might be difficult to make by naked eye, but a scanning electron microscope could reveal a world of difference. So says John Weisel, a University of Pennsylvania cellular and structural biologist who has spent decades divining the mechanics of the very small, particularly the biophysics of blood clotting But he, like London, has heard the call of the wild. And it's taken him places miles from power lines, let alone electron microscopes. It's what drew him to spend several weeks of his sabbatical on the remote Isle Royale in Lake Superior.