Caesium Ions do not Pass the Membrane of the Giant Axon Pickard, W. F. ; Lettvin, J. Y. ; Moore, J. W. ; Takata, M. ; Pooler, J. ; Bernstein, T. Abstract Publication: Proceedings of the National Academy of Science Pub Date: November 1964 DOI: 10.1073/pnas.52.5.1177 Bibcode: 1964PNAS...52.1177P