William A. R. Thomson

Preface This book is based upon a series of talks given by experts in the External Services of the British Broadcasting Corporation, to whom I am indebted for permission to make use of them. Little of the originál talks survive, however, apart from the title of the book. This is largely due to the...

preface to the twenty-fourth edition In preparing this new edition, many sections have been revised or rewritten and many new ones have been added. Among the sections that have been entirely rewritten are those on chronic alcoholism, detergents, influenza, leprosy, mental defectiveness, mental...