To document the plague of littered cigarette butts that I write about in the October 29 issue, I grabbed a camera and walked a several-block perimeter around the headquarters of the American Chemical Society in downtown Washington, DC. It's a lovely and clean-appearing urban area, that is, until you train your eyes toward the streets and sidewalks. I was in search of cigarette butts and I found them everywhere�along the street curbs, on sidewalks, in the textured tops of iron manhole covers, in the rectangular slots of metal street gratings, in buildings' window wells, in sewage portals, atop tinder-dry mulch beds, sometimes even in the ashtrays and butt receptacles that many facility managers have placed at the buildings' entry ways. In recent years, the tobacco industry has been producing more than 5 trillion cigarettes, serving some 1.1. billion smokers. No one knows how many of the resulting butts end up as litter, but one 45-minute stroll around a small part of one downtown area suggests that the number is best written out in exponential notation.