1. Contribution from the Department of Food Science, Stocking Hall, Cornell University,
Ithaca, New York 14853, H. H. Wills Physics Laboratory, University of Bristol, BS8 1TL, U.K.,
Department of Biochemistry, University of Bristol, BS8 1TD, U.K., Centre de Recherche sur la
Matière Divisée, 1 bis rue de la Férollerie, 45071 Orléans, France, and School of Pharmacy,
University of Maryland, 20 Penn Street, Baltimore, Maryland 21201