'Eyw rpwvry OiWTO EV Tli E(}'rllup JOHN, J, 23 A SURVEY OF THE PRINCIPAL WORKS on histological technique that have th appeared since the end of the 19 century shows such a diversity of concept and directive ideas, in spite of the fundamental unity of subject, that the choice of the underlying orientation was perhaps the most difficult problem facing me when MM. Masson & Cie, requested me to write this book. A classification of these works based on their particular orientation and carrying the excess inherent in all that is schematic would lead to the definition of three types of books. Some...