The noble gift of effective oratory has been denied me by Nature. Though I have taught for eighty-eight terms at the little University of Jena, I have never been able to overcome a certain nervousness about appearing in public, and have never acquired the art of expressing my thoughts in burning language and with appropriate gesture. For these and other reasons, I have rarely consented to take part in scientific and other congresses; the few speeches that I have delivered on such occasions, and are issued in collected form, were drawn from me by my deep interest in the great struggle for the triumph of truth. However, in the three Berlin lectures--my _last_ public addresses--I had no design of winning my hearers to my opinions by means of oratory. It was rather my intention to put before them, in connected form, the great groups of biological facts, by which they could, on impartial consideration, convince themselves of the truth and importance of the theory of evolution. Readers who are interested in the evolution-controversy, as I here describe it, will find in my earlier works (_The History of Creation_, _The Evolution of Man_, _The Riddle of the Universe_, and _The Wonders of Life_) a thorough treatment of the views I have summarily presented. I do not belong to the amiable group of "men of compromise," but am in the habit of giving candid and straightforward expression to the convictions which a half-century of serious and laborious study has led me to form. If I seem to be a tactless and inconsiderate "fighter," I pray you to remember that "conflict is the father of all things," and that the victory of pure reason over current superstition will not be achieved without a tremendous struggle. But I regard _ideas_ only in my struggles: to the _persons_ of my opponents I am indifferent, bitterly as they have attacked and slandered my own person. Although I have lived in Berlin for many years as student and teacher, and have always been in communication with scientific circles there, I have only once before delivered a public lecture in that city. That was on "The Division of Labour in Nature and Human Life" (17th December, 1868). I was, therefore, somewhat gratified to be able to speak there again (and for the last time), after thirty-six years, especially as it was in the very spot, the hall of the Academy of Music, in which I had heard the leaders of the Berlin University speak fifty years ago. It is with great pleasure that I express my cordial thanks to those who invited me to deliver these lectures, and who did so much to make my stay in the capital pleasant; and also to my many hearers for their amiable and sympathetic attention. ERNST HAECKEL. JENA, _9th May, 1905_. CHAPTER I THE CONTROVERSY ABOUT CREATION EVOLUTION AND DOGMA EXPLANATION OF PLATE I GENEALOGICAL TREE OF THE VERTEBRATES