At this juncture each year, INC. revamps its Index, plugging in a lineup distilled from the INC. 100 list of the fastest-growing public companies in America. For readers who suspect that switching to young bodies gives INC. a distinct advantage, we point to the chart. The fresh blood bumbled badly after the transition, despite three-figure revenue gains over five years. Continuing to be shaken by bad earnings in big companies, investors jettisoned unfamiliar situations by the hundreds, throwing out INC.'s new babies with the wash. Not that the brood wasn't soiled by earnings troubles of its own. To recover standing now will take a rally in speculative issues the likes of which Wall Street has yet to witness. Still, stranger things have happened.