THE BEAT GOES ON

CHICAGO—Muddy Waters holds up a massive, pleated hand, waving it through the air 'til the late morning light falls on its fleshy furrows. The hand is folded with age; mottled like a harpooned whale, with callouses and a long, razor thin scar that extends up along a meaty finger (one of the reasons Waters has gradually phased out his slide guitar theatrics).