div class=ts-pagebuttonPage 1button div class=ts-image amp-img class=ts-thumb alt=Page 1: Sir John Gaddum FRS src=https:reader037vdocumentssitereader037viewer20221004215750682e1a28ab0f07aef9d4html5thumbnails1jpg width=142 height=106 layout=responsive amp-img divp© 1965 Nature Publishing Grouppdiv