IN the News and Views section of Nature of May 18, 1968 (ref. 1), attention is directed to a recent paper by Pape, Multani, Stitt and Saltman2, in which a new model for ferritin synthesis is proposed. The authors suggested that ferritin formation occurs by way of aggregation of apoferritin subunits around a preformed polynuclear iron micelle and that their mechanism accounts for the apparent induction of ferritin synthesis by iron. While welcoming this new hypothesis, we would like to indicate that results obtained by several other groups of workers support the alternative view that apoferritin molecules are formed first and that these then accumulate iron in their interior to give ferritin.