The bolder elements met in congresses, and encouraged each other in the pursuit of their ideal. But it at once became clear in their public discussions that some of their purely scientific discoveries were dangerous and heretical in such a period of reaction. This or that had hitherto been buried innocently in scientific monographs, quite unknown to the crowd, and the author might be a royal councillor, receive decorations, and almost be an elder of the Church. Suddenly, by means of these assemblies, the sinfulness of all this lore about snails or insects or vertebrates was brought to light and put before the profane public, and there was much anger. The whole of scientific research was full of secret plots, heresies, and bombs—against God.
There was a most appalling illustration of this in the Scientific Congress, held in September, 1863. Nothing is more amusing to-day than to run through the yellow and almost unknown papers of the Congress. They are illuminating to some extent. An idea that belongs to humanity is openly brought into the debate for the first time. Ages lie behind this hour. We must grant all that savours of human comedy, of triviality even, in such an assembly, but after all we must see in it the swell and clash of great waves. Haeckel spoke for the first time on Darwin’s theory, at a spot from which the waves were bound to spread through the whole scientific culture of the land. Virchow, afterwards his bitter opponent, supported him. All the deepest questions and consequences of Darwinism were mooted with the first vibrant accents. It was a great and unforgettable hour.
The first speaker at the Congress on the Sunday evening, September 19, 1863, was Haeckel. We must remember the charm that attached to his person even outwardly, the direct charm that did not need any allusion to his growing repute in zoology. It was the charm that had been felt by the simple folk of uncultured Italy, who had never heard even the name of the science. Darwin was never a handsome man from the æsthetic point of view. When he wanted to sail with FitzRoy, it was a very near question whether the splenetic captain would not reject him because he did not like his nose. His forehead had so striking a curve that Lombroso, the expert, could put him down as having “the idiot-physiognomy” in his Genius and Insanity. At the time when he wrote the Origin of Species he had not the patriarchal beard that is inseparable from his image in our minds; he was bald, and his chin clean shaved. The prematurely bent form of the invalid could never have had much effect in such a place, no matter what respect was felt for him. Haeckel, young and handsome, was an embodiment of the mens sana in corpore sano. He rose above the grey heads of science, as the type of the young, fresh, brilliant generation. It was an opponent at this Congress, who sharply attacked the new ideas, that spoke of the “colleague in the freshness of youth” who had brought forward the subject. He brought with him the highest thing that a new idea can associate with: the breath of a new generation, of a youth that greets all new ideas with a smiling courage. Behind this was the thought of Darwin himself, a wave that swept away all dams.
The speech was as clear as crystal, and is still useful as an introduction to the Darwinian question. He at once strikes the greatest and the dominant note. Darwin means a new philosophy. All organisms descend from a few primitive forms, possibly from one; and man is one of these organisms. What Darwin had merely hinted in his concluding passage, what the aged Bronn had excluded altogether from his translation as too dangerous, was now set forth emphatically in the very beginning of his speech. “As regards man himself, if we are consistent we must recognise his immediate ancestors in ape-like mammals; earlier still in kangaroo-like marsupials; beyond these, in the secondary period, in lizard-like reptiles; and finally, at a yet earlier stage, the primary period, in lowly organised fishes.”
There is something monumental in this passage, as in the previous confession of Darwinism in the Monograph on the Radiolaria. Others may have come to similar conclusions at the time on reading Darwin’s work. Here we have the profession made at the psychological moment, a trumpet-blast that sent its thrilling alarm from the threshold of a new age, for friend or foe to hear. The speech gives a slightly exaggerated account of the struggle that already existed. All was in confusion. Science was breaking up into two camps. On the one side evolution and progress, on the other the creation and immutability of species. Already there are distinguished leaders of science in favour of evolution. It is time to discuss the matter in full publicity—and the thing is done.
There was, let me say parenthetically, on the Continent at least no question at that time of this clear division, or even of a serious agitation. It was partly this speech, together with Haeckel’s next work, that was to bring it about. To the highest authorities the subject seemed to be below the level of discussion. We must recall a passage that the Professor of Zoology at Göttingen, Keferstein, had written a year before in the Göttinger Gelehrte Anzeiger. “It gives great satisfaction to the earnest scientific worker,” we read, “to see a man like Agassiz, with an authority based on the finest zoological works, reject unreservedly a theory [Darwin’s] that would discredit the whole work of classifiers for a century, and to see that the views built up by several generations and the general consent of humanity hold a stronger position than the views of a single individual, however eloquently they may be stated.” There is no idea in this of two regular camps of scientists. Humanity is adduced as the one party; against it stands the anarchist, trying to blow up the work of centuries, Darwin. But that gave no concern to the young orator; he saw a whole decade of success in the first attack.
He rolled off geology. Cuvier’s theory of catastrophes, Linné’s belief in the immutability of species—all a purely theological cosmogony. The “philosophical theory of evolution” rises behind it like a Mene Tekel Pharshim.
All living things, including those of past geological epochs, form one great genealogical tree. The word, the new leading word for zoology and botany, comes out with a flash. What is the system that has been awaited so long? It is the genealogical tree of life on our planet. Its roots lie deep in the remote past. “The thousands of green leaves on the tree that clothe the younger and fresher twigs, and differ in their height and breadth from the trunk, correspond to the living species of animals and plants; these are the more advanced, the further they are removed from the primeval stem. The withered and faded leaves, that we see on the older and dead twigs, represent the many extinct species that dwelt on the earth in earlier geological ages, and come closer to the primeval simple stem-form, the more remote they are from us.”
This was the great new idea for science to work upon. Paleontology, the science of past life, found at last a common task with botany and zoology. Haeckel’s own programme for decades was unfolded. This phrase, too, was a birth-hour. In all the struggle that has followed as to the “how” of evolution this figure of the tree with the verdant branches as the new field of zoological and botanical work, and the withered branches for the paleontologist, has never been abandoned. A symbol from the living world itself, the branching tree, had at last taken a decisive place in the science and the classification of living things. With splendid clearness the speech then enumerates the Darwinian principles: variation, heredity, the struggle for life, selection, and adaptation. A vast duration is claimed for the geological epochs in the sense of Lyell; and it is pointed out that there is a progressive advance of forms throughout these periods. Special stress is laid on the ever-advancing, ever-uplifting element in evolution. Man is again introduced into the subject. He has “evolved” from the brutality of the animal. Language itself has been naturally “developed.” (What a shrewd perspective in such a brief phrase! How the philologists would stare!) So the “law of advance” traverses the whole field of culture. A fiery passage follows: “Reaction in political, social, moral, and scientific life, such as the selfish efforts of priests and despots have brought about at every period of history,” cannot permanently hinder this advance. The “advance” is “a law of nature,” and “neither the weapons of the tyrant nor the anathemas of the priest can ever suppress it.” We hear again the older Sethe thundering his intrepid reply: “You will have to shoot the law first.”
At the close he glances briefly at the difficulties the theory presents. We must regard even the first beginnings of life as the outcome of “evolution.” Naturally. Darwin’s God has no use for this prophet. But how shall we conceive it? Was the thing that first developed from the inorganic “a simple cell, such a being as those that now exist in such numbers as independent beings on the ambiguous frontier of the animal and vegetal worlds?” Or was it a particle of plasm merely, “like certain amœboid organisms that do not seem to have attained yet the organisation of a cell”? Again the simple question contained a whole programme.