The International Life Sciences Institute (ILSI) was creat ed to promote cooperative efforts toward solving critical health and safety questions involving foods, drugs, cosmet ics, chemicals, and other aspects of the environment. The officers and trustees believe that questions regarding health and safety are best resolved when government and industry rely on scientific investigations, analyses, and reviews by independent experts. Further, the scientific aspects of an issue should be examined and discussed on an international basis, separate from the political concerns of individual companies. The Institute is pleased to sponsor this set of monographs on pathology of laboratory animals. This project will help to improve the scientific application of the techniques of pathology to the evaluation of substances in our environ ment. The worldwide distribution of the authors, editors, and editorial board encourages the expectation that inter national communication and cooperation will also be strengthened. Alex Malaspina President International Life Sciences Institute Preface This book on the endocrine system is Volume I of a set of reference books on pathology of laboratory animals, prepared by the Interna tional Life Sciences Institute in response to recommendations from its Committee on Pathology and Toxicology. One aim is to provide infor mation which will be useful to pathologists, especially those involved in studies on the safety of foods, drugs, chemicals, and other sub stances in the environment."

The International Life Sciences Institute (ILSI) was creat ed to promote cooperative efforts toward solving critical health and safety questions involving foods, drugs, cosmet ics, chemicals, and other aspects of the environment. The Officers and Trustees believe that questions regarding health and safety are best resolved when government and industry rely on scientific investigations, analyses, and re views by independent experts. Further, the scientific aspects of an issue should be examined and discussed on an international basis, separate from the political concerns of individual companies. ILSI is pleased to sponsor this set of monographs on the pathology of laboratory animals. This project will be use ful in improving the scientific basis for the application of pathologic techniques to health and safety evaluation of substances in our environment. The world wide distribu tion of the authors, editors, and Editorial Board who are creating these monographs strengthens the expectation that international communication and cooperation will al so be strengthened."

Laboratory Animal Medicine has made enor We deeply appreciate the efforts of each of the mous strides in the 47 years since R. Jaffe published authors and co-authors of the 23 chapters in this his "Anatomy and Pathology of Spontaneous Dis two volume work. In some instances the reader will eases of Small Laboratory Animals" in 1931. So note what appears to be repetition in certain chap ters. This repetition was allowed to stand in some much new information had accumulated that in a cases because different approaches seemed useful, new edition in 1958, Jaffe, aided by Cohrs and Meessen, needed the assistance of 46 colleagues to although efforts were made to delete most of the do the subject justice. Like its predecessor, this two redundancy which inevitably arises in a venture of volume comprehensive treatise on "Pathologie der this kind. We will be grateful if our colleagues point out errors and send us specific and general Laboratoriumstiere" was written in German and criticism of this work to allow corrections in the thus not readily available to the widening circle of event of reprinting or a next edition. veterinarians and pathologists who now are inter One objective has been to assemble current in ested in laboratory animals. Aside from the need to have a comprehensive formation in the pathologic aspects of diseases of review of laboratory animal pathology in English, laboratory animals."