See New Scientist, 26th June, pp. 32-35 (and place your order for a tricorder) Have a good weekend ;-) Paul Dr Paul M. Kirk Biosystematist CABI Bioscience Bakeham Lane Egham Surrey TW20 9TY UK tel. (+44) (0)1491 829023, fax (+44) (0)1491 829100, email p.kirk at cabi.org www.cabi-bioscience.org