In the beginning of April, 1905, I received from Berlin a very unexpected invitation to deliver a popular scientific lecture at the Academy of Music in that city. I at first declined this flattering invitation, with thanks, sending them a copy of a printed declaration, dated 17th July, 1901, which I had made frequent use of, to the effect that "I could not deliver any more public lectures, on account of the state of my health, my advanced age, and the many labours that were still incumbent on me."

I was persuaded to make one departure from this fixed resolution, firstly, by the pressing entreaties of many intimate friends at Berlin. They represented to me how important it was to give an account myself to the educated Berlin public of the chief evolutionary conclusions I had advocated for forty years. They pointed out emphatically that the increasing reaction in higher circles, the growing audacity of intolerant orthodoxy, the preponderance of Ultramontanism, and the dangers that this involved for freedom of thought in Germany, for the university and the school, made it imperative to take vigorous action. It happened that I had just been following the interesting efforts that the Church has lately made to enter into a peaceful compromise with its deadly enemy, Monistic science. It has decided to accept to a certain extent, and to accommodate to its creed (in a distorted and mutilated form) the doctrine of evolution, which it has vehemently opposed for thirty years. This remarkable change of front on the part of the Church militant seemed to me so interesting and important, and at the same time so misleading and mischievous, that I chose it as the subject of a popular lecture, and accepted the invitation to Berlin.

After a few days, when I had written my discourse, I was advised from Berlin that the applications for admission were so numerous that the lecture must either be repeated or divided into two. I chose the latter course, as the material was very abundant. In compliance with an urgent request, I repeated the two lectures (17th and 18th April); and as demands for fresh lectures continued to reach me, I was persuaded to add a "farewell lecture" (on 19th April), in which I dealt with a number of important questions that had not been adequately treated.

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.