Frederick Ridley was born in Birmingham, where his father was a schoolteacher. Having graduated BSc at Birmingham in 1922 he took the MB, BS in 1925 and the FRCS in 1928. As a young man he worked with Fleming on lysozyme, and his basic work on purification helped in the subsequent development of pen

Hyla Bristow Stallard, always known as Henry to his many friends, was born in Leeds on 28 April 1901. He went to a preparatory school in Cheltenham and then to Sherborne where in addition to success at his work he also began to show the athletic prowess which so distinguished his later career at Cam