the Pathology of Laboratory Animals are designed to facilitate communication among those involved in the safety testing of foods, drugs, and chemicals. The complete set will cover all organ systems and is intended for use by pathologists, toxicologists, and others concerned with evaluating toxicity and carcinogen­ icity studies. The international nature of the project - as reflected in the composition of the editorial board and the diversity of the authors and editors - strengthens our ex­ pectations that understanding and cooperation will be im­ proved worldwide through the series. Alex Malaspina President International Life Sciences Institute Preface This book, on the eye and ear, is the tenth volume of a set prepared under the sponsorship of the International Life Sciences Institute (ILSI).