Christian de Duve, at the Catholic University of Louvain, identifies in 1955 — together with Pressman, Gianetto, Wattiaux, and Appelmans — a new cell organelle while studying enzyme distribution in rat liver tissue fractions: a membrane-bound particle containing hydrolytic enzymes active at acidic pH, functioning as the cell's digestive "stomach". He names it the 'lysosome'. Years later, at the Ciba Foundation Symposium on Lysosomes (London, February 12-14, 1963), de Duve coins in a single session the terms 'autophagy', 'endocytosis', and 'exocytosis', and persuades Novikoff to rename his 'cytolysomes' as 'autophagic vacuoles'. He receives the Nobel Prize in Physiology or Medicine in 1974, shared with Albert Claude and George E. Palade, for their discoveries concerning the structural and functional organization of the cell.