Professor Morton was Johnston Professor of Biochemistry in the University of Liverpool, 1994–66. He served on the Council of the Royal Society, 1959–61, and on the Council of the Royal Institute of Chemistry, 1955–61. He was the first Chairman of the British National Committee for Chemical Education and of the Food Additives and Contaminants Committee. He has also served on many committees dealing with vitamins, bread and flour, nutrition and biological research generally. In recent years he has been active on committees of the Natural Environment Research Council.This lecture was given to a varied audience of staff and students at the University College of Aberystwyth on 25th February 1970. The Executive Editor is pleased to be able to publish this interesting and thought-provoking discourse on a problem of ever-growing importance.