Preface Information about the distribution of chemical elements in animals and plants is scattered throughout a wide range of periodicals and is continually growing in volume. The present book aims to survey the field while it is still small enough for an overall view. The aim has been a critical and not an encyclopaedic coverage, and a real effort has been made to cut down references to original papers when these are listed in recent reviews. Such a treatment inevitably lacks completeness, and the author here extends his apologies to all those whose papers are not referred to in the text. Despite the wealth of published work, much remains to be learned in this field. Until recent years, the elementary composition of common organisms was established only for about a third of the periodic table, and even today data are scanty for more than half the elements and for many important phyla. Advances are also needed in our quantitative knowledge of elementary cycles, such as the nitrogen cycle, and in the techniques of chemical purification and analysis needed to establish biological essentiality. Relatively little is known about the uptake and function of many essential elements, as is shown by the isolation of proteins containing traces of metals whose functions are still obscure. The recent contamination of the planet with radioactive fission products has focused attention on the behaviour of many rare or neglected elements in the Biosphere, and has shown up our ignorance of the distribution of natural radioactivity. Concern has also been expressed about the pollution of air and water with toxic elements, which can often be directly linked with human disease. This book is therefore aimed at post-graduate workers on academic problems concerning trace elements. It should be of especial interest to chemists and biochemists, as well as to biologists, ecologists and health physicists. It is a pleasure to thank numerous colleagues for discussions on individual points and, in particular, Drs. E. J. Hewitt, J. E. Thomas and A. Wild who read and criticized parts of the manuscript. Reading July 1966 H. J. M. Bowen

Bowen J.M.

Trace elements in biochemistry