"The professoressa is a bit tired," an adviser to Rita Levi-Montalcini warned me as I prepared to interview Italy's Nobel prize-winning Life Senator on the eve of her 100th birthday. "Don't wear her out." I arrive to find the professoressa, as she is universally known, in the dress shop below her office in Rome, in an elegant black dress buttoned to the neck and a gold brooch of her own design, white hair immaculately coiffed, examining the rails of clothes with close and lively attention.