"One day I blew my nose and half my brains came out."Los Angeles, 1976. David Bowie is holed up in his Bel-Air mansion, drifting into drug-induced paranoia and confusion. Obsessed with black magic and the Holy Grail, he's built an altar in the living room and keeps his fingernail clippings in the fridge. There are occasional trips out to visit his friend Iggy Pop in a mental institution. His latest album is the cocaine-fuelled Station To Station (Bowie: "I know it was recorded in LA because I read it was"), which welds R and B rhythms to lyrics that mix the occult with a yearning for Europe, a