3rd edition. — Longmans Green & Co., 1964. — 690 p.
This third edition has been revised to bring it up to date. This has been made possible by the information I have obtained from articles written by experts on important developments in their field of research. Since the volume of research published on topics dealt with (and not dealt with) in this book make it impossible to include all new work, I have therefore had to choose, but any deficiencies in my choice are, I hope, partly compensated by the reading references given at the end of each chapter.