CHAPTER VI. The “general Morphology”

THE “GENERAL MORPHOLOGY”

The speech at the Scientific Congress in 1863 was the first open confession that Haeckel felt bound to make. But the real work for the new ideas began on his return to Jena. Nothing was further from Haeckel’s thoughts at that time than the idea of becoming merely the populariser of Darwinism in Germany. He has often been spoken of since in lay circles as such. It is entirely wrong. He had the courage to recognise his debt whenever he contracted one; and certainly Darwin supplied the groundwork of his colour-scheme. But he was much too independent and individual in his nature not to take the axe in his own hand at once and begin to hew away himself.

Darwin had strengthened his book with a large amount of the best material that zoology and botany could supply. But there was something else to be done: a theoretical treatment of a general character with cleverly grouped illustrations from the facts already provided by two sciences, and to reconstruct these sciences from their foundations on the basis of the new theory. At that time Haeckel was doing an incredible amount of work, with body and mind. He had an iron constitution. In the year of the Stettin speech he won a laurel crown at the Leipsic athletic festival for the long jump, with a leap of twenty feet. His physical strength seemed so inexhaustible that his host, Engelmann, put a pair of heavy iron dumb-bells in his bed, in case he should want to take exercise during the night. He had a proportionate strength of mind. Everything seemed to promise very well for the next few years, so that he could devote his whole health and strength to the great task of his life. His teaching did not give him very much trouble in a small university like Jena, that was only just beginning to have a scientific name. The happiness of his home life, with a highly gifted woman who shared all his ideas with the freshness of youth, began to chain the restless wanderer with pleasant bonds to his place. He, of course, expected to have his sea-holiday in the old way for the study of his little marine treasures, but otherwise he remained quietly in the valley of the Saale. The warmth of genial and most stimulating friendships gathered about his life. With his comfortable material position he set to work on his great task under the best auspices.

He would have had at the start material enough to work upon without Darwin. From Müller’s time he still had another special class of material, similar to the radiolaria, the medusæ.

The ship cuts through the ocean. It rises like a lofty fortress from the illimitable blue plain, with the white clouds on the far horizon. No land has been in sight for days. Yesterday a poor wind-borne butterfly rested on the deck. To-day it is gone, and all is sea. Then they suddenly appear silently in the blue mirror: mysterious discs, red as the anemones on a Roman meadow in spring, golden as the autumn leaves on a dark pond in the park, then blue, like a lighter blue floating on the general azure. They are the medusæ. At one time the ship sails through a whole swarm of them—thousands, hundreds of thousands, millions, a veritable milky way of coloured stars. On the next day they have all gone. No inhabitant of the ocean seems to be so close to it as this creature. The whole animal is only a shade more substantial than the water. You take it out, and try to catch hold of it. It stings your hand like a nettle: that is its one weapon. But it is already destroyed, melted away, a formless nothing. You put it on a piece of blotting-paper, and it dries up into the spectral outline of a shadow, a tiny “fat-spot,” summary of its whole existence.

Yet this soap-bubble of the water is a real animal. Its transparent body is shaped like a bell, and moves through the water by regular contraction and expansion, like the lung in breathing. Where the clapper of the bell should be, we find a stomach, with a mouth for eating, hanging down from the curved upper part. At the edge of the curved surface are many long fibrils that close on the approaching prey and paralyse it by their sting. Then it thrusts it into its mouth and swallows the object into the stomach. The medusa is, of course, a very lowly creature, but it is much more advanced in organisation than the tiny radiolarian. The radiolarian consists of a single cell. The medusa is a cell-state, a community of countless cells with a division of labour amongst them. Some of the cells form the wall of the bell, some the stinging threads, some the devouring and digesting stomach. In this the medusa comes nearer to man than the radiolarian. Some of the cells see to the reproduction of the medusa. Ova and spermatozoa are detached from the cell-community of the medusa’s body, blend together, and thus form the germ of a new medusa. In most cases the process is curious enough. From the germ-cell we get at first, not a real medusa, but a polyp that attaches itself to the ground, a little creature that may be remotely compared to the pretty water-lilies that meet the eye in an aquarium. Then the polyp produces something like a plant that grows buds, the real medusæ; it may produce these out of its substance as buds, and they then float away like detached flowers, or (in other species) it may gradually change itself into a chain of medusæ, of which the uppermost is detached first, then the next, and so on.

Since this peculiar method of reproduction became known, in the thirties or forties, the medusæ were regarded as amongst the most interesting objects in the whole of zoology. They offered an extremely difficult task to the investigator who would care to take up the study of them.

When Haeckel was with Johannes Müller in Heligoland in 1854 he made acquaintance with them for the first time. His artistic eye was caught with their beauty, as it was afterwards with the radiolaria. “Never shall I forget,” he says, “the delight with which, as a student of twenty years I gazed on the first Tiara and Irene [species of medusæ], and the first Chrysaora and Cyanea, and endeavoured to reproduce their beautiful forms and colours.” His predilection for the medusæ never disappeared. At Nice in 1856 he met them again in the Mediterranean. Gegenbaur’s Sketch of a Classification of the Medusæ provided his studies with a starting-point, just as Müller’s writings did afterwards for the radiolaria. At Naples and Messina he completed his mastery of them. When he had done with the radiolaria for the time after publishing the great monograph of 1862, the next task that loomed up on his horizon was the need for a “monograph on the medusæ.” It would be a long time, however, before he could complete the work in any fulness. A work of Agassiz that purported to do it, but, in his opinion, only confused the subject—he disliked both the Agassizs, father and son, and the father became one of his bitterest opponents on the Darwinian question—gave him a negative impulse to the study. He thought it would be best to deal with one family of the medusæ after another in separate monographs, as time permitted. The first of these essays appeared in 1864 and 1865, and dealt with what are known as the “snouted-medusæ” (geryonidæ). The first volume of the complete work was not published until fourteen years afterwards. If Haeckel had decided to work as a specialist he would have had material enough here to occupy him fully throughout the whole of the sixties, and even longer. The keen student of the radiolaria would be succeeded by the equally keen student of the medusæ. More folio volumes would have accumulated, with beautiful plates, such as only the technical student of zoology ever takes out of the library. His name, like that of his friend Gegenbaur almost, would never have reached the crowd.

It was the influence of Darwin that prevented this. His attention was turned in another direction, and we begin to realise the full greatness of his power when we remember that he nevertheless continued with unfailing quality to publish such detailed studies as those on the medusæ.

Darwinian ideas were fermenting intensely in his mind at that time. The most audacious practical and theoretical problems arose from the fundamental theory, and forced themselves on him at every moment. A great deal was sketched in outline in the Stettin speech, but the serious scientific work would have to be begun on his return to Jena, in his view. First, he thought, two features of Darwin’s system must be given a completely new and original complexion. Firstly, the bottom of the tree, where life begins. Secondly, the crown of all terrestrial evolution: the manner in which man is connected with the tree. It was his philosophic vein that settled both points, the philosophy of unity that sought to replace God by natural development, both below and above, in regard to the primitive cell and in regard to man. But the way in which he set about it was very far removed from all conventional philosophy. The whole rigour of his professional zoology found expression in it. And that was really the novelty of it. The same conclusions might have been drawn by any dozen ordinary philosophers, once they got on the right track. Even they could see that, if two and two are four, one and one are two, and three times three nine. Haeckel went very differently, and much more profoundly, to work.

ERNST HAECKEL, 1890. From a relief-portrait modelled by Kopf, of Rome. ]

As an old pupil of Virchow’s he applies the cell-theory to Darwinism—in the lower stage. The first living things, the roots of the great tree of life, consisted of a single cell. The logic of the cell-theory itself went as far as this. But is the individual cell the simplest of all living forms? Here there was a long-standing controversy as to definitions. At first the cell was regarded literally as a kind of chamber, like the cell in the honeycomb. Then it was found that the jelly-like, mobile matter within the cell-chamber was the essential element, the vehicle of life. Finally, it was possible to conceive this slimy substance without any firm membrane, without a chamber. Inside it, however, there was always (it was then thought) a thick and hard substance, the nucleus. If that was the fundamental and only really essential form, the Darwinian primitive and initial type of all terrestrial life must have been a similar drop of living matter with a solid central nucleus, a nucleated individual cell.

How could we pass from this primitive cell to the “inorganic,” the “lifeless,” the “dead,” the ordinary matter of stone, metal, and crystal? Haeckel believed that it was possible to make a step in that direction—not theoretically and philosophically, but practically—by showing that there were still living things on the earth that did not come up to the definition of a true cell, things that had not yet a nucleus in their soft gelatinous body. He discovered a number of tiny creatures that had a homogeneous particle of living matter for body, and showed no trace of a nucleus. The nucleus seemed to be the first beginning of an organ. It was altogether wanting in them.

To these most primitive of all living things he gave the name of monera, or the absolutely “simple.”

In these investigations it is very difficult to determine whether one of these tiny drops of plasm has a more or less transparent nucleus or not. It has often been affirmed in later years that these monera of Haeckel’s did not correspond to their description as living things without a nucleus, or creatures that were below the level of the true cell. It is, at all events, certain that there are to-day large numbers of the unicellular beings known as the bacteria in which no nucleus has yet been discovered by the most sceptical Thomas with the most powerful microscopes and best technical appliances of our time. It is the same with the chromacea (chroococci, oscillaria, nostoc-algæ), very lowly primitive plants whose whole body consists of a globule or granule of living plasm. However, here again the question is no longer of the first importance, now that evolution is entirely and generally accepted. At the time we are discussing the method chosen was all-important. Haeckel drew no conclusions without a solid basis. He believed he could give ocular proof of the existence of beings that were below the level of the cell. It was clear, at all events, that research in this department was only in its beginning, and could pour out wonder after wonder before the world recovered from its first fright over Darwinism.

Then there was the other end of the system—man. Here again it was not merely a question of concluding on philosophic grounds that man must have descended from the lower animals. Huxley had dealt in England with the question of man and the ape on the strict lines of zoology. He came to the important conclusion that man differs less zoologically from the highest apes, the gorilla and chimpanzee, than they do from the lowest apes. He proved his point by a technical study of skulls and brains, not from abstract philosophical principles. It could be demonstrated in the museum or zoological institute to any student with some knowledge of anatomy as easily as the existence and position of any particular bone in the skeleton. Haeckel went even further.

He constructed a genealogical tree stretching far below the apes. Next to them came the lemurs. The lemur, the ghostly nocturnal inhabitant of Madagascar, came from the Australian marsupial (kangaroo, &c.). The marsupial came from the duck-bill; the duck-bill from the lizard; the lizard from the salamander; the salamander from the dipneust or mud-fish; this from the sturgeon or the shark, and the shark from the lamprey. Below the lamprey, at the lowest limit of the vertebrate kingdom, was the amphioxus (or lancelet). This must have come from the worm—it was not at all clear how, at that time. And so the series ran on down to the unicellular protozoa, the amœbæ and the monera.

The construction of this tree would have been impossible for one who had not already done gigantic work. The whole of the new system of animals and plants, conceived in the form of a genealogical tree, had first to be sketched in outline. Then the narrower thread that led up to man, the Ariadne-thread of God-Nature, would gradually come to light.

Both ends of the system, the lower one in the monera, the upper one in man, were first thoroughly treated by him in 1865, and in part somewhat later. His exhaustive Monograph on the Monera was not published until 1868. Man’s genealogical tree was privately circulated at Jena in two essays in October and November 1865. They were published in the Virchow-Holtzendorff collection in 1868 (“The Origin and Genealogical Tree of the Human Race”). But in both cases the substance of the work, as an accumulation of facts, is much older. And this work was, of course, only possible in connection with a number of further conclusions: in regard to spontaneous generation, life and death, the crystal and the cell, the mathematical form of organisms, the nature and limits of individuality, the method of research, the new natural philosophy, God, and so on.

It was an enormous programme, with a Paradisaic freshness. Everything was new and great; and all came from one brain. There was only one man with whom he discussed his ideas as they formed, Carl Gegenbaur, who has undoubtedly had a great, if unconscious, influence on them. Haeckel’s grateful recognition of Gegenbaur’s help in later years was endless and touching. “Thou it was,” he writes to him a little later, “that led me to begin my academic teaching at our beloved Jena six years ago, at the Thuringian university in the heart of Germany, that has, like a beating heart, sent out its living waves of freedom and alertness of mind over Germany for three hundred years. At this nursery of German philosophy and science, under the protection of a free State whose princely rulers ever gave a refuge to free speech and have linked their names for ever with the reform movement, the golden age of German poetry, I was able to work in association with thee. Here we built up our common structure of science in the happiest division of labour, teaching and learning cordially from each other, in the very rooms in which Goethe began his studies of ‘the morphology of organisms’ a half-century before, and partly with the same scientific means, the germs of comparative and philosophic science that he had scattered. We have shared with each other as brothers the happiness and the sorrow that came in the hard struggle for life, and our scientific efforts have been so intimately blended and so mutually helpful, through our daily working and talking together, that it would have been impossible for either of us to determine the particular share of each in our spiritual communism. I can only say in a general way that the little my restless and impulsive youth could offer thee here and there is out of all proportion to the enormous amount I have received from thee, eight years my senior, a more experienced and mature man.”

Goethe stood behind the friends as the quiet genius loci, giving his blessing to all who worked in his spirit on the old spot. Nor was the place itself without influence. “Much,” Haeckel writes, “may have been even the outcome of the common uplifting enjoyment of nature that was afforded us by the artistic lines of the Jena hills, as they brought before us once more at sunset the magic of the Calabrian mountains by the colour-harmony of their purple and gold banks of cloud and their violet shadows.”

“What are the hopes, what are the plans, that man, the creature of a day, builds up?”

The words were written by a poet, in his fatal illness, at the spot where the two strong spirits now worked. In the midst of all his hopes and plans Haeckel was struck by a Niobe-shaft. On February 16th, 1864, just on his thirtieth birthday, his wife, only in her twenty-ninth year, in the full force of mind and of love, succumbed to blood-poisoning.

I turn to the thick volume of Haeckel’s Monograph on the Medusæ. Part I.: “System of the Medusæ:” with an atlas of forty beautiful plates: published by Gustav Fischer, of Jena, in 1879. Few people except zoologists with a technical interest in it have ever opened this voluminous work—why should they? It is a heavy work, with dry diagnoses. The author seems to be far away from all general questions, if ever he was, in the utter stillness of his study. This pure accumulation of matter for truth’s sake does not reach the ear of the world. It lays up material for remote days, before which the individual fades away; it is merely catalogued material of the most technical character. Yet, as I turn over the pages, I seem to see a little image from time to time that is almost like the rose-red or golden-brown medusæ in the sterile, illimitable ocean. In truth neither ocean nor book is sterile; but they are grey and broad. And just as the swimming medusa gladdens me in the one, so a little personal trait of the author does in the other. It is in the choice of the Latin names. A little crown is woven that unites æsthetics and science. I find splendid names, invented by the Professor, on all sides. But I notice that his heart was in these things. He has discovered new species of medusæ, and must christen them. As he turns over his Latin or Greek lexicon a ray of humanity steals into the most severe scientific soul at such moments. I read that a disco-medusa is called the Nausicaa phæacum: “I observed the Nausicaa phæacum in April, 1877, at Corfu, on the shore of Phæaca, in the heart of the Nausicaa.” A cyaneid is given the fine name of the Melusina formosa. It is noted, with great regret, that “so fine and classic a name for a medusa” as Oceania must be struck out on scientific grounds. Amongst descriptions of species in a severe scientific tongue that unnerves the timid reader, amongst gonods, styles, perradial bundles of tentacles, and ocellar bulbs, we find, apropos of the medusa, Lizzia Elisabethæ: “As Forbes dedicated the pretty genus Lizzia blondina to a ‘blond Elizabeth,’ I do the same, and wish to honour, not only St. Elizabeth of Thuringia, but also the ‘blond Elizabeth’ of Immermann and my own dear daughter Elizabeth.”

Then, in the middle of the large volume, we find the following passage on page 189. A medusa is given the name of Mitrocoma Annæ. The name was given at Villefranche, near Nice, in April, 1864 This medusa had “a fairy-like appearance” to its discoverer; its tentacles hung down “like a mass of blond hair!” A note to the name tells us that it was given “in memory of my dear, never-to-be-forgotten wife, Anna Sethe. If it is given to me to do something during my earthly pilgrimage for science and humanity, I owe it for the most part to the blessed influence of my gifted wife, who was torn from me by a premature end in 1864.” In the Art-forms in Nature, Haeckel’s work of 1899, we find a medusa Desmonema Annasethe similarly—after thirty-five years—apostrophised: “The specific name of this pretty disco-medusa, one of the most beautiful and interesting of all the medusaæ, immortalises the memory of Anna Sethe, the gifted and refined wife (born 1835, died 1864) to whom the author of this work owes the happiest years of his life.”

If one would fathom the depths of human emotion one must reflect what these words, in such a context, contain; it is the last gentle vibration of a most deep inner experience breaking out into this prosaic, scientific material. A medusa is a trivial, possibly a funny thing, to the layman. The man of science looks deeper into it, and sees a wonderful revelation of nature; the eye of Goethe’s God shines on him from it. But when he has devoted years to the most careful study of it, it assumes also a naïve individual interest for him, as the companion of his solitary hours of observation in the heart of nature, far from all the whirl and bustle of the world. Only the deepest and most intimate feelings break out in such moments. And here they have left their monument—in a Latin name that science will go on coldly entering in its catalogues for ages to come. It seems to me that this simple fact tells us more of the character of this true-hearted man, in whom nothing human was lacking, than long narratives could.

* * * * *

When the aged Sethe saw the break-up in 1806 of the State of Prussia, in the invulnerability of which he had believed as a gospel, he sought refuge in the comfort of work. “I succeeded in benumbing my mind: I experienced in myself that hard work is a soothing balsam, co-operating with our tardy healing force.” The grandson, wounded in a more terrible way and cut to the very heart, tried the same remedy.

Thirty years afterwards, when crowns were prepared and speeches delivered in honour of Haeckel’s sixtieth birthday, when the whole of Jena fêted him as their own, and the veil fell from his marble bust in the Zoological Institute, to which seven hundred of the best known names in German and foreign science had contributed, the hero of it all went back to that dark hour. “I thought at the time that I could not survive the blow, thought my life was closed, and purposed to bring together all the new ideas that Darwin’s theory of evolution had evoked in me in a last great work. That was the origin, amid bitter struggles, of the Generelle Morphologie. It was written and printed in less than a year. I lived the life of a hermit, gave myself barely three or four hours sleep a day, and worked all day and half the night. My habits were so ascetic that I really wonder I am alive and well before you to-day.”

In his hour of collapse Haeckel sat down and wrote “the book of his life.” There were only two alternatives for a book written in such circumstances. It would be either very bad or very good. When a young man in his thirties throws himself into a great effort of this kind and writes a work that he conceives as a testament—a work in which he will speak for the last time, but will say everything—it is a desperate test of all that he has done in his three decades of life and is about to give to the world. In this case the test succeeded beyond all expectation.

The General Morphology of Organisms was published in 1866, with the sub-title: “General elements of the science of organic forms, mechanically grounded on the theory of descent as reformed by Charles Darwin.” It consists of two thick volumes of small print, containing more than 1,200 pages. The preface is dated September 14, 1866. It is now one of the most important works in the whole mental output of the second half of the nineteenth century. In respect of method of scientific research it is a landmark by which we may characterise and appraise the whole half-century. For general biological classification it inaugurates a new epoch, as had been done fifty years before by Cuvier, and again fifty years earlier by Linné. What it did for zoology in the narrow sense was thirty years afterwards summed up in one phrase by a writer of acknowledged competence, Richard Hertwig: “Few works have done as much towards raising the intellectual level of zoology.” Among Haeckel’s own achievements, great and varied as they are, this work occupies the highest place. Setting aside certain special pieces of research, and regarding him mainly as a man of great ideas, we find his whole programme in this work. The History of Creation, that has taken his name far and wide over the globe beyond the frontiers of zoology, is only an extract from this work. He put his heart in it. The others are only the improved blood-vessels of his system of ideas, partly duplications, partly simplifications. I do not say this either in blind admiration or in criticism, but as the expression of a plain fact. Posterity will turn to this work when, either in hostility or in sympathy, it wishes to appreciate Haeckel.

Footnote 2:

This work of Professor Haeckel’s has not been translated into English. [Trans.]

Footnote 3:

Professor Huxley described the General Morphology as “one of the greatest scientific works ever published.” [Trans.]

His contemporaries did not accept the work without difficulty. It came out without noise, exerted a tremendous influence in a quiet way, and at last disappeared altogether from the bookshops. It is still attacked, but has never been refuted. At libraries one finds, as I know from experience, that it is always “out,” and therefore must be read continually. It is found occasionally at second-hand booksellers; an antiquarian price running to five pounds and more is put on it, after forty years’ active production on the part of its author. At present you could count on your fingers the German works that have this distinction of being highly priced and out of print. One such is Vischer’s Æsthetics, and another is the first edition of Gottfried Keller’s Green Henry. Keller had threatened any one who ever attempted to republish this first edition (afterwards modified but not improved by him) that their hand would not rest quietly in the grave. But the price of the work went up amongst antiquarians. I feel, in speaking of Haeckel’s General Morphology, that I am describing a book which has become so rare that one must treat it as something new, a codex that is only accessible to a few. It is certainly not known to the general reader.

Let me endeavour in a few words to give a general idea of the chief contents of the work.

All the intellectual forces that had had any influence upon Haeckel now concentrated for a supreme achievement. First of these was Goethe, who supplied the title, “Morphology.” In its simplest signification morphology is merely “the science of forms.” If I take houses, furniture, statues, fishes, flowers, crystals, &c., and only regard and describe their forms, I am a morphologist in the literal sense of the word. But when Goethe invented the term he sought to give it a more restricted application, writing in the style of earlier days, but clearly enough, at Jena in 1807. We have, he says, natural objects before us, especially living objects. We try to penetrate the secrets of their nature and their action. We are not merely observers, but philosophers. It is from this point of view that we approach the subject. It appears to us that the best way to proceed is to separate the various parts. Such a procedure seems calculated to take us very far. Chemistry and anatomy are instances of this analytic kind of research, and both are greatly esteemed and successful. But this method has its limitations. “We can easily break up the living thing into its elements, but we cannot put these together again and restore them to life. We cannot do this in the case of many inorganic, to say nothing of organic, bodies.” What are we to do? “Hence,” Goethe continues, “even scientific men have at all times had an impulse to recognise living things as such, to grasp connectedly their external visible and tangible parts, and take these as indications of the inner life, and thus in a sense to compass the whole in one glance.” “Hence we find at the threshold of art and knowledge and science a number of attempts to establish and elaborate a science that we may call morphology.”

Perhaps Goethe’s meaning can be realised best if one takes a great work of art—say, the Venus of Milo—and imagines how these different kinds of knowledge would deal with it. Purely analytic anatomy would dissolve the superb artistic form into a rubbish-heap of bits of marble. Chemistry would still further break up these bits of marble into the chemical elements of which every block of marble is ultimately composed. The “form” would disappear altogether. But in this case the form means—the Venus of Milo. We see at once that we need another branch of science and investigation besides anatomy and chemistry: we need a morphology, or science of the complete form in which the block of marble is moulded into the Venus of Milo. In the case of our work of art, morphology would be identical with æsthetics, or at least with a branch of it. There can be no doubt that the first and most imperative need for the establishment of a special science of morphology arises from artistic and æsthetic feelings. It is not without significance that it was founded by the poet Goethe, and elaborated with such great success in the nineteenth century by the born artist Haeckel. However, that does not prevent the analogy of the Venus of Milo, which happens to be a creation of human art, being applied equally to every individualised form in nature, to every crystal, plant, and animal. Goethe himself immediately transferred his morphology into the province of botany with such vigour that the term is still regarded, in its narrower sense, as a technical botanical expression. It extends, however, to the whole world in so far as its contents come before us in “forms.” When Haeckel adopted the term he deliberately restricted it, in harmony with the general definition, by calling his work the “Morphology of Organisms,” or the science of the forms of animals and plants.

But there was one danger in the conception of a morphology of animals and plants, namely, the danger of taking it to mean a purely external description: so many thousand species of plants, soberly described, labelled, and numbered, a huge cabinet of stuffed skins, a herbarium of hay. A whole scientific school had really taken it in this sense since Goethe’s time; much as if one were to think æsthetics consisted simply in forming an illustrated catalogue of all the art-treasures in the world, a realistic catalogue in which the marble statues from the Parthenon and the Moses of Michael Angelo would simply be given as number so-and-so in class so-and-so.

Haeckel was preserved from this school by his more immediate masters, as well as by Goethe himself; firstly by Johannes Müller, then by the botanist Schleiden, finally by the influence of Gegenbaur. There was at the time enough, and more than enough, of this external museum-morphology. It was far from Haeckel’s intention to produce a new compendium, in several volumes, of this kind of science of plants and animals. His morphology was to be “general,” to have a broader range, be a programme. As Richard Hertwig said very happily at a later date, he saw his science, not as it then was, but as it ought to be, in his opinion.

The science of forms was to be in the fullest sense a “philosophy of forms.” “Zoological philosophy” was the name given by the hapless Lamarck, in France a century ago, to a work that appeared in the year that Darwin was born, and anticipated his most advanced thoughts. Haeckel, also, gave a new “philosophy of zoology and botany.” The title embodies the magic formula that gave him courage to take up resolutely once more the proscribed word, that seemed to have been scalded and spoiled for ever in the witches’ cauldron of “natural philosophy”; it spoke of the “theory of descent as reformed by Charles Darwin.” Two sub-titles divided the work into two sections from the start. The first part was, the critical elements of the mechanical science of the developed forms of organisms (animal and plant); the second part was, the same elements of the mechanical science of the developing forms of organisms.

In these titles we see the decisive advance beyond Johannes Müller. As Goethe had already declared, morphology as such can be formed into a real and profound science. It will then not confine itself pedantically to a registration of forms. It will compare them with each other, and seek the hidden law in the straggling phenomena. It will mark out broad lines that will enable the human mind to grasp its objects in all their fulness. Johannes Müller had only been able to confirm that in the narrower sphere of biology. This was the nerve that gave vitality to zoology and botany, and made them a province of the mind in the higher sense. But the question now was: which laws were detected, and in which category of thought were they to be found? Müller had the theory, but was weak on the practical side. There were the “forms” of animals and plants. What was it that really connected them? What was the reality that corresponded to the philosophic craving of the intelligence? Müller’s next school, the generation immediately preceding Haeckel, that of Du Bois-Reymond, Virchow, and many others, had apparently indicated the solution. They had replaced Müller’s vague general conception of the laws of morphology and life, which was undermined by older influences, by a single great demand. We want to grasp nature as a unity. At one point in nature we have reached deep and apparently fundamental factors—in physics and chemistry and their plain natural laws or forces. Now let us try, starting from the idea of unity and from the plainest of all philosophical principles, that of proceeding from the known to the unknown, to reduce the forms and phenomena of life to these natural laws of chemistry and physics. Let us find out whether the whole form-world of the animals and plants—in other words, the whole province of morphology in the narrower sense—can be traced to the same natural laws that we have in chemical and physical phenomena. The globe is the object of chemistry and physics. Shall these few green or other-coloured things that lie at the limit of the air, water, and rocks, a small minority in nature, the things we call animals and plants, alone in the whole world be exempt from the action of these laws? It is immaterial that Müller’s best pupils, Du Bois in his later years and Virchow at an early date, departed more or less from this consistent position of theirs into philosophic and other sidepaths. The younger generation, to which Haeckel belongs, that only came into direct touch with Müller in his last years, heard no other gospel. What further advance was to be made? In chemistry and physics they had before them the deep stratum that yielded good mechanical laws. The first stage of physiology after Müller, as we find it, for instance, under Du Bois-Reymond, yielded some good indications for the organic. But was the whole of morphology to be remodelled? Was the vast labyrinth of the thousands and thousands of animal and plant forms in the museum to be reduced to mechanical laws, corresponding to those of physics and chemistry, and be explained by them?

Darwin brought salvation. Now that he had appeared, Haeckel felt that he could begin to work. The hour and the man were come.

Darwin made it possible for him to raise morphology to a penetrative science, equal to physics and chemistry, and so to make a step towards the unity of our knowledge of a unified world. Hitherto the morphology of the animals and plants had been in confusion. God, imagined in the form of a higher man, had deliberately created the organic forms, the palm, the moss, the turtle, and the man. He had constructed them on a definite plan, as a man makes machines. Now, it appeared, the deeper stratum was peeping out even here. Laws that had built the heavens and the earth reached, by way of the Darwinian theories of selection and adaptation, to the moss and palm, the turtle and man.

It was Haeckel’s peculiar distinction to take up this path as the right one. It was then altogether new; to-day, even in the eyes of an opponent, it has at least the solid and consistent support of a considerable party. In later years, apart from open deserters from the free and uncompromising pursuit of truth like Virchow, a school of zoologists and botanists has been formed that will not recognise in Darwinism a reduction of vital phenomena to the simple chemico-physical laws of the rest of nature. They look upon it partly as inaccurate in its allegations of fact, partly as a nebulous confusion, if not, as I have already said, as a false mysticism or metaphysic. In the opinion of these critics, whose own confused ideas very often leave little to be desired in point of nebulosity, and who frequently try to drive out the devil by means of the devil’s grandmother (a matter we cannot go into here), Haeckel had made a great mistake in thinking that Darwinism would solve the Du Bois-Virchow problem of reducing all living things to the laws of lifeless matter. Even these, however, must candidly acknowledge that in doing so he was the victim of his consistent and honourable inquiry. At all events he must logically have seen the correct line at that time as it is recognised to-day by this anti-Darwinian but professedly mechanical school. His individual error can only have been that he was deceived as to the true course of the line, and so clung to Darwinism. However, we have said enough on this point.

Haeckel himself, at the time he was producing his greatest work, saw in Darwin the absolute “open Sesame” to all the doors of philosophic morphology. With this Sesame came an entirely new impulse, namely, to write the natural history of the animal and plant form. It was just the same as when æsthetics perceives a new world, a world that alone is worthy of it, the moment it passes from the making of a mere catalogue of the world’s art-treasures to the knowledge of even one single law of artistic creation, in virtue of which one single work of art has been actually built up.

It is impossible to begin with more general considerations than this book does. The method of scientific research generally is explained in order to give an idea of the new Darwinian morphology. With a calmness that must have made most of the contemporary zoologists and botanists shiver, the discredited idea of natural philosophy is restored from the lumber-room. “All true science is philosophy, and all true philosophy is science. And in this sense all true science is natural philosophy.”

The various periods in the development of morphology are coolly schematised. These epochs are characterised by the vicissitudes of the struggle between the simple description of forms in the animal and plant worlds and the philosophic exposition of the laws that lie behind these forms. In the eighteenth century, under Linné, there is a period of purely external description and classification. It is succeeded in the first third of the nineteenth century by a triumph of the philosophic treatment of animal and plant forms. This increases with Goethe and Lamarck, and grows into the older (and now generally abused) imaginative natural philosophy. Then there is a general reaction; with Cuvier comes the least philosophical of methods, though at the time it is a real advance. While Linné only gave an external description of forms and catalogued them, Cuvier’s epoch penetrated to the inner structure, the inner world of forms, and thus rendered great service. The last and greatest workers of the period, Müller, Schleiden, &c., give the signal for a reaction in the hour of its chief triumph. Haeckel now follows this up as “the element of fact in their ideas.” With Darwin he inaugurates the fourth epoch, the triumph of natural philosophy for the second time. But it is now far deeper and clearer; it embodies all the good that preceded, all that Cuvier and his followers have done, without the irresolution of earlier days. Now that we have studied the living form in its innermost structure, as was never done before, in the earliest stages of embryonic development in the ovum and womb, in the past geological periods of the earth’s history, we will think over this form, think with all the means at our command, reason, synthesis—even imagination, when it is necessary to press on to the great final conclusion, a new synthesis of the defective positive data. What does Johannes Müller say? “Imagination is an indispensable servant; it is by means of it we make the combinations that lead to important discoveries. The man of science needs, in harmonious co-operation, the discriminating force of the analytic intelligence and the generalising force of the synthetic imagination.” That is spoken from the depths of Haeckel’s heart, and he drives it home.

Nothing is more amusing than to find Haeckel’s later opponents saying, apropos of any particular question, that his statement springs from his “imagination,” as if it were something wholly unscientific that the naturalist must shun like the pest; or again, that Haeckel here or there falls a victim to the deadly enemy of all scientific research, natural philosophy. It is pointed out to him as a great discovery which he must approach in a proper penitential spirit—to him who has discussed these matters so unequivocally in his first theoretical work.

As a fact, these methodological chapters in the first volume are as clear as crystal. The titles will seem strange to the man who thinks he can do without any philosophical instruction in zoology and botany, and wants to hear only of cells, tissues, stalks, leaves, bones, scales, and so on, in a general morphology. One chapter has the heading: “Empiricism and Philosophy (Experience and Knowledge).” Another heading runs: “Analysis and Synthesis.” Then there are: “Induction and Deduction,” “Dogmatism and Criticism,” “Teleology and Causality (Vitalism and Mechanism),” “Dualism and Monism.” The last three antithetic headings are united under a general title as “Critique of Scientific Methods that are Mutually Exclusive.” Such a title illumines the whole situation like a flash of lightning. Many years afterwards Haeckel himself said of his General Morphology that it was a comprehensive and difficult work that had found few readers. At least the whole of this first and most difficult part of the book must be defended against the criticism of its parent. If it is far from adequately appreciated to-day, especially by professional philosophers, that is certainly not due to its style, which is a model of clearness in the eyes of any one with the least philosophical culture. The real evil was that people did not look to it for instruction from the philosophical side. The title, “Morphology of Organisms,” had a technical sound. The empty space between professional philosophy and professional zoology is wide enough to-day, but it was far wider thirty-four years ago. Books like Büchner’s superficial and popular Force and Matter, or Haeckel’s own later work, the History of Creation, that can only be regarded as a brief and incomplete popular extract in comparison with the General Morphology, with all its peculiar literary charm, stole into the philosophy of the time like foxes with burning straw tied to their tails. Professional philosophers have written whole libraries on them. The matter recalls a fundamental defect in academic philosophy: it has little or no sympathy with real scientific work; in fact, it studiously avoids such sympathy in the consciousness of its own weakness. Hence it has, like every other layman with general interests, to wait for attempts to popularise scientific work before it can know what is going on in the serious camp. The man who wants to-day to criticise the mechanical conception of nature should first make himself acquainted with these chapters of the Morphology. How many know the mere title of the work? How many even of those who evince great hostility whenever Haeckel’s name is mentioned?

The book contains much more than the methodological introduction. This only takes up the first hundred pages, but it contains the whole programme. We start off, therefore, under full sail for a new epoch of thought, for natural philosophy; but we must keep an alert mind. The deeper task, that Darwin only gave the means of accomplishing, was to reduce all living things, animal or vegetal, to the inorganic. The laws of life must be merely certain complications of the simple laws that are encountered directly in chemistry and physics, and rule throughout nature. It must be one of the first aims of a general philosophic morphology to open out a path in this direction.

The living and what is called the “dead” must be compared. Linné’s three rigid kingdoms—animal, plant, and mineral—needed definitions in harmony with the new ideas. Haeckel himself had discovered the “monera,” the living particles of plasm that did not seem to have reached the stage of the true cell. Here, clearly, was the lowest level of the living. At the same time we reach the most complex specimen of the inorganic from the morphological point of view—that is to say, the most interesting in its individual form—the crystal. The differences begin to give way. What marvellously similar functions! From the dead mother-water is built up, purely by chemico-physical laws, the beautiful structure of the crystal. From the lowest living particle of plasm without any special organs, as we see in the radiolaria, are formed the beautiful siliceous frames that Haeckel had collected in such quantities at Messina. Is it more than a hair’s breadth to pass from one to the other? The deeper we go in the study of living things, the slighter become the differences that separate them from “dead matter.” On the other hand, the higher we go in the structure of crystals, the more striking is the resemblance to the living thing. Two chains of thought seem to be started. What we call “dead” is really alive: what we call living is really subject to the same laws as the “dead.” The solution is found in complete Monism. Living and dead are not antithetic. Nature is one; though we see it in different stages of development. We call one of them the crystal, another the cell, or the moneron, or the protozoon; another the plant, another the animal. Historically it all hangs together. The same laws hold sway throughout. In framing my arbitrary definitions I can say either that the dead is living, or that the living does not differ essentially from the dead. In the chain of living things man comes from the primitive cell, the moneron. This in its turn has developed from something earlier—“naturally” developed. The very idea of life forces us to seek the predecessors of the monera. Hence we speak of “spontaneous generation,” as what was dead according to our ordinary use of language has begun to live. In point of fact it is merely development of a unified whole. There is no gap, no leap, no act that is not natural. The dead and the living never were really antithetic.

The insistent statement that not only does the living approach the inorganic, but the inorganic approaches the living, is quite “Haeckelian.” The study of the “life” of crystals is one of the best parts of the book. Later generations will appreciate it. We are much too narrow to-day when we merely reflect that life, even the life of man, can be traced by evolution down to what we call dead matter. We forget that this “matter” is already high, since it potentially contains life, and even man, the crown of life. Many people imagine that the derivation of man from “dead matter” is equal to turning a king into a beggar. They do not reflect that, on the other hand, a beggar is turned into a king. When I say that life arose one day out of the inorganic, or that a crystal was turned into a cell, my statement really involves the complementary truth that the inorganic potentially contains life in itself. Otherwise we have the old miracle over again of something being produced out of nothing, in spite of our spontaneous generation. Haeckel has always been clear on this point. His later studies of the soul of the atom and the plastidule only carry out the absolutely logical treatment of the question that we find in these chapters of the first volume of the Morphology.

Incidentally the question is raised whether the plant or the animal was evolved first. Animal and plant are, of course, not rigidly distinct from each other. They are only the two great branches of the Darwinian evolution of living forms, and are united at the bottom, however much they diverge above. Gegenbaur had represented this years before (1860) in a figure that Haeckel quotes in his Monograph on the Radiolaria in 1862. The whole kingdom of living things must be conceived “as a connected series, within which we find two lines diverging from a common centre and representing a gradual differentiation and development of organisation.” The terminal points of these lines (the highest plant and the highest animal) are very different from each other, but the difference gradually disappears as we go back towards the common centre, and the lowest stages in each kingdom can hardly be distinguished from each other. For these lowest stages Haeckel now carries out a plan that very quickly forced itself on him.

He forms them into a new kingdom of life. To the animal and plant kingdoms he adds the primitive realm of the beings that showed unequivocal signs of the possession of life, yet were neither animals nor plants. He gives them the name of “Protists.” To botany and zoology is now added protistology.

The name “protists” (from protiston, the very first) is familiar to every one in biology to-day. If protistology has not yet been securely established as a special branch of science, that is due to the circumstance that a strict limit cannot be determined on either the plant or the animal side, so that the botanist encroaches on the province at one point and the zoologist at another. But when we remember that Haeckel’s protists include the well-known bacilli, on which whole libraries are accumulating to-day, it is clear that the province must be definitely marked off at some date in the near future, whether one accepts Darwinism or no.

These important innovations in technical biology show very clearly how sound and fruitful the new “natural philosophy” was. We have to go back to the untenable and utterly impracticable systems of Hegel, Schelling, and Steffen, which were immediately rejected as the trifling of dilettanti, or even to much that the admirable Oken did on the scientific side, if we would measure the whole distance between what people understood in the sixties by “natural philosophy” and the real reformed philosophy that Haeckel gave to the world. This becomes clearer at every step we take in his work.

The first book has determined the method that leads to morphology, the science of forms. The second has ranged the organic forms—protists, plants, and animals—over against the inorganic or “dead” forms, as far as this is possible from the new evolutionary point of view. We feel that the third book will pass on to Darwin, and explain the world of organic forms by the Darwinian laws of evolution. Then the programme would be carried out in its main features.

But Haeckel writes two whole books before he comes to this, and they are, perhaps, the most characteristic in the work. He only “adopted” the theory of evolution in the sense that he applied it far more thoroughly than Darwin to practical problems. In these two books he is entirely himself. They are, at the same time, the most difficult in the work. Even to-day they place him on a lofty and lonely height apart from the great and strenuous controversy over Darwinism. I believe that the time will yet come that will fully appreciate these books. Through them Haeckel will play a part in philosophy of which we have at present no prevision.

There is a word that is inseparable from the word “form”—individuality. Morphology, which does not analyse, but studies the form-unities as a whole in the sense of Goethe’s definition, comes from the nature of things to deal with the individual. In our artistic illustration the Venus of Milo, as a form-unity, is an æsthetic individuality. When its form is destroyed, its individuality perishes.

Let us apply this to any one of the higher plants or animals. Take a turtle, for instance. A definite individual embodies the definite form to which I give the name. This form as such is entirely lost if I cut up the turtle until it is unrecognisable. The limit of morphological study seems to be, just as in the case of the Venus of Milo, the integrity of the individual turtle. Yet in the living turtle we find an enormous difference.

If I grind the Venus of Milo into dust, I am at once in a totally different world with this dust. I am amongst the raw material of nature, untouched by æsthetic influence. From this calcareous powder I can, in reality or imagination, pass on to the world of crystals, molecules, and atoms. In that case I shall have done with æsthetic morphology. I come to the morphology of the inorganic, a very different branch. What do we find in the case of the living turtle?

It is true that I can break up the turtle into simple chemical substances. In that case I make the same transition; I abandon organic morphology, and pass, with the same salto mortale as in the case of the Venus of Milo, to the lower science of inorganic morphology.

But when I examine the structure of the living individual turtle before me I notice a special feature. Let us suppose that I break up the Venus of Milo only to a certain degree; or, with less vandalism, I do not break it up, but light up its inner structure to some extent by a sort of Röntgen-ray apparatus. And suppose I found that this one æsthetic individuality is made up of millions of much smaller and æsthetically finer and more unified images. I do not mean of millions of repetitions of the large Venus in miniature, but of real and unmistakable little works of art, each of which, regarded separately and without any injury to its narrower individuality, might be just as excellent a subject for æsthetic examination as the whole Venus.

This is, of course, nonsense as regards the Venus of Milo. There is nothing of the kind in it. I have given the paradoxical supposition merely for the purpose of showing what we really find in the case of the turtle.

When the organic individual turtle is closely studied it breaks up first into so many simpler organic individuals, which undoubtedly belong as such to the province of organic morphology. They are the cells. The theory of Schleiden, Schwann, and Virchow here comes into direct touch with morphology. Every higher animal or plant has its own individuality; and within this individuality there is a conglomerate, a community, or a state, of individuals of a lower order, that have their own life and their corresponding individual life-form. Man himself, the highest of animals, is a cell-state. So Virchow taught. Each one of us is an individual, and as such an object of morphology. The cell, each single cell in each of us, is also an individual, and as such is equally an object of morphology. Hence it is the task of the morphology of organisms, not only to describe these higher individualities as such, but also to look on them as glass-houses, as it were, with so many shelves, divisions, and smaller houses within of a lower rank. These internal arrangements have to be described, piece by piece, with the same fidelity.

This will probably suffice to convey a general idea of the subject. Clearly, the great work that ought to form the general part of morphology at this point was the precise determination of all these various layers of individuality that are found in the animals, plants, and protists, and, as we rise upward, enter into more and more complex relations to each other.

The difference between, say, a turtle or a man and the cell which combines in its millions to form them is not the only one. Between them we seemed to find individualised, or almost individualised, links. Think of the idea of an organ. What is my heart? It is made of a number of cell-individuals, like my whole frame. But these cells form a sort of intermediate individuality in me. We may go further. What is a segment of a worm? What is an arm of a star-fish? They have so much independence that they can continue to live, rapidly producing new cells and forming a new worm or star-fish of the higher individual type, if they are cut off. The arrangement is still more difficult in the case of the plant. Where in their case shall we find the stages of individuality that correspond to the animal-human? The cells are distinct in both cases. The individual plant-cell corresponds to the individual animal-cell. But what is there in the plant that corresponds to me, as the animal-human multicellular individual? Does the oak-tree, for instance? Certainly, the oak is an individual. But it seems that it is the single sprout of it that corresponds to what I am. What is the relation of the tree to this sprout?

Here our ideas grow dim and confused. We human individuals unite to form certain higher communities. The word “social” reminds us of the fact: then we have the nation, the race, humanity. At least the earlier of these stages certainly perform various combined functions, and are understood to form, or wish to form, new individuals. We speak of the social organism, the body of the people, the soul of the people, and so on.

We see that still more clearly in the case of the animals about us. Individuals, that correspond to our conception of an individual man, combine and form stocks and colonies, with division of labour. We find this in the medusæ, corals, anemones, tunicates, and vermalians. One of these animal stocks, to which our human social combinations only correspond in a much wider sense, gives us a stage that is represented by the tree in the plant-world. Infinite perspectives open out, and also infinite complications. Infinite problems spring up for morphology to deal with; it must make its way through the labyrinth of these complicated types of individualisation.

The matter is still more intricate if I begin at the bottom of the biological series and proceed upwards. I, man, am an individual of a certain stage in my own collective activity. It is true that I am made up of millions of cell-individuals, but when we look at the whole these are merely elementary units. But take a being from the protist-world that is too lowly to be either animal or plant. In respect of its whole activity it is an individual just as much as I am, and therefore in this regard at the same stage as I. At the same time it consists of a single cell. The distinction in me between unit and whole does not exist in it. Its unit is the whole. It would seem a Sisyphean task to reduce all this to a system.

Yet that is just what Haeckel has done.

With crystalline clearness he separates and reunites and arranges everything, from the primitive organic individual, that is not yet a true cell—the monera he had himself discovered—upward. Organic morphology begins with them as its first object, the first complete individuality, the first “form.” All that lies below it is beyond the province of morphology. The last conceivable organic individuality is, perhaps, the atom; and that is not the concern of morphology. We start from the organic. Above the pre-cellular individuals and the true cells the next form-unities are the organs. Above the organs, after a few subtle intermediate stages, are the “persons.” Thus a new word is given to what we have hitherto conventionally called an “individual,” when we wanted to denote a turtle, a bird, a man, or an higher animal as a whole. To this corresponds in the plant the sprout. The stage above the “person” is the “stock.” We might also call it the social individual; in the plant-world it is the tree, in the coral the coral-stock, in the human case the social combination of a number of men for common action.

We are reminded of Virchow’s speech, and how “consciousness” was dragged into the debate on the cell-state. What psychological perspectives are opened out by this doctrine of individuality! Each form-unity, each single individuality in the series, with a soul! Souls combining for common action, and forming higher psychic unities! There is no detail in Haeckel’s whole life-work in which he speaks more boldly and freely and philosophically than he does here. His lucid treatment raises to a higher stage a philosophic question that has occupied thinkers for ages.

That is the third book. The fourth takes up a different subject. Let us adopt in organic morphology this wonderful theory of individuality, the theory of stages within the form. Then let us turn to consider impartially the vast multitude of living forms. How can we now arrange this infinite confusion by merely looking at it? Artificial classification has attempted it a hundred times, and always without success. On this side there is only one way to proceed—the mathematical.

I study them with strictly mathematical figures. I determine their axes, and the mathematical aspects of their forms. Possibly that will give a practical result; the only kind of artificial system that can be accommodated with the Darwinian theory, and perhaps render it assistance by the sharpness of its lines. Does it answer? Take a crystal, a specimen from inorganic morphology. The description of it is susceptible of a strictly mathematical form. Now take a star-fish, a worm, a human being. We find that even these organic structures have a mysterious relation at bottom to certain mathematical, stereometric forms. We might almost say, to certain forms of human thought. Everything in the organic world is in a state of flux. But through the whole moving stream we can trace the outline of one stable element, something like a mathematical idea. A sort of Platonism of the living forms vaguely takes shape.

Haeckel speaks of lines, axes, circles, radii, and all kinds of rhythmic structures. It does seem that the countless individual forms of living things fit into a scheme of a limited number of mathematical forms. Strictly speaking this is not a real morphology of living things. We only find these clear and rigid forms schematically in the wild profusion of forms of the protists, plants, and animals. They are only a reminiscence of the laws of the purely inorganic, which the eye of the observer just detects as the lowest stratum. Hence Haeckel calls this section the “promorphology” of organisms.

It is true that this section, which essays to compress all living things into a very simple scheme, is the hardest to read in the whole work. A number of strange and difficult words have to be invented for this stereometric scheme to which he would reduce the animal and plant forms. Haeckel himself declared, twenty years afterwards (in the second part of the Monograph on the Radiolaria), that this stereometry of organic forms had found little favour in biology “especially on account of the difficult and complicated nomenclature.” But he had complete confidence as to the substance of it, even after so great a lapse of time.

In point of fact we have here, it seems to me, a gigantic preparatory work, not so much for the strict purpose of classification, as for a real philosophy of botany and zoology that will be founded some day. This recurrence of sharp stereometric structures, not only in the crystal, but also, if less clearly, in the biological world, will one day prove an important source of knowledge, in a sense that is not even clear in Haeckel himself.

We are already entering upon a period that has a glimpse of the truth that the deepest power of Beethoven’s music, or Goethe’s poetry, or Raphael’s painting, or Michael Angelo’s sculpture is a mysterious revelation of the most subtle mathematical relations and effects—produced without conscious perception of these relations, though a human mind is at work in them. In spite of all our “consciousness,” the obscure intuitive power at work in these human artistic achievements differs very little from the curious force with which a radiolarian builds up its little house in the deep-sea or a caseworm fits on its fine, rhythmic, snail-like coat. In both we have the same profound, crystal-like constructive power that brought forth the wings of the butterfly, the feathers of the bird, the bodily frame of all the animals and plants, that harmonises so well with strict mathematical forms. In Beethoven and Raphael it is not more conscious or unconscious, not clearer or vaguer, not more mystical or more natural, than in the poorest worm or the microscopically small radiolarian. The æsthetics of the twentieth century will take up these ideas.

* * * * *

HAECKEL’S VILLA AT JENA. ]

It is a great work. How few there are in the whole of the nineteenth century that show the wealth of ideas we find in the first volume alone. And this is only one volume. We have as yet said nothing of the idea that is of the greatest consequence in connection with Haeckel’s own development. He was a Darwinian from 1862 onwards. After 1866 and the publication of the General Morphology we find him dominated in all his work by one single idea from the Darwinian group. He brought this idea so effectively to the front, improved and developed it so assiduously, and applied it in so many ways, that it has come to be regarded as his own most characteristic work. It is inseparable from his name. Whatever the future may be, wherever Haeckel’s name is uttered people will add the phrase that was made peculiarly his after 1866, that colours and pervades all his works—technical, popular, polemical, or philosophical—as much as the word “Monism.” It is the phrase: the biogenetic law.

Footnote 4:

The reader may be interested to know that Haeckel gives a popular summary of his early work on individuality and on the mathematical types of organisms in a more recent work. This has been translated into English with the title The Wonders of Life. The two chapters that deal with these questions are omitted from the abridged cheap edition. [Trans.]

Here and there even in the first volume of the Morphology a note is struck that the reader cannot clearly understand. It increases in the second volume until it dominates the whole book.

The phrase is known far and wide to-day. This is partly due to Haeckel’s own insistence on it, but perhaps still more to the real value of the idea itself. It crops up in a hundred different fields—psychology, ethics, philosophy, even in art and æsthetics. I have been able to trace it even into modern mysticism. For the moment I will only point out that it has been attacked and misstated with real fanaticism, in spite of the splendid and perfectly clear account of it that Haeckel has given.

The proper place to read of it is, as I said, the second volume of the Morphology. This volume has to give an account of the evolution of organic forms. What is given rather casually, almost Socratically, in Darwin is now developed into a number of strict laws. This method of expounding more or less hypothetical, new, and insecure ideas in the form of laws has since been frequently attacked. Some have been led by it to take the ideas as so many dogmas, and even to learn the laws by heart as if they were texts in Scripture. Others have then laid the blame of this dogmatic interpretation on Haeckel himself. It is quite true that there was the possibility of a misunderstanding. People do not always think for themselves, and the statement of a proposition in the form of a law may prove a pitfall for them. The blind learning of them by heart is always mischievous. On the other hand, it might be urged that the statement of the ideas in this bald way affords the best opportunity for a thorough and rational criticism of them, precisely because they give such pregnant expression to the writer’s meaning. I do not find that order and strict logical definitions have ever done any harm of themselves, whatever it is that is put in order and defined. On the contrary. People must confuse order sometimes with real dogmatism. Of this there is not a word in the whole book, while at an important juncture the reader is actually warned to be on his guard against undue pressure. “In this,” we read in the twentieth chapter, “we do not wish to draw up a body of laws of organic morphology, but to give hints and suggestions for drawing them up. A science that is yet only in its cradle, like the morphology of organisms, will have many important changes to undergo before it can venture to claim for its general propositions the rank of absolute and unexceptionable natural laws.”

However that may be, it was in this provisional definition of laws that the famous biogenetic law first took shape, and with it a spirit entered into Darwinism in the narrower sense that was never again detached from its master, Haeckel.

Let us once more take a simple illustration from facts. Take a green aquatic frog and a fish, say a pike.

Both of them have a solid vertebral column in their frames, and therefore both must be classed amongst the vertebrates. But within the limits of this group they differ very considerably from each other. The frog has four well-developed legs, its body terminates in a tail, and it breathes by means of lungs, like a bird, a dog, or a human being. The fish has fins, it swims in the water by means of these fins and its long rudder-like tail, and it breathes the air contained in the water by means of gills. When we arrange the vertebrates in a series, with man at their head, it is perfectly clear that the frog stands higher than the fish in regard to its whole structure. It is lower than the lizard, the bird, or the mammal, but at the same time it is a little nearer to these three than the fish is. That was recognised long ago by Linné, who assigned them a corresponding rank. The fishes are the lowest group of the vertebrates; the frogs belong to the group immediately above them. Now let us see how one of these frogs is developed to-day. The frogs are oviparous (egg-laying) animals. The mother frog lays her eggs in the water, and in the ordinary course of nature a new little frog develops from each of these eggs. But the object that develops from them is altogether different from the adult frog.

This object is the familiar tadpole. At first it has no legs, but it has a long oar-like tail, with which it can make its way briskly in the water. It breathes in the water by means of gills just like a fish. It is only when the tadpole grows four legs, loses its tail, closes up the gills at its throat, and begins to breathe by the mouth and lungs instead, that it becomes a real frog. There can be no doubt whatever that the tadpole is very much more like the fish in all the most important particulars than the frog. Between the frog-egg and the frog itself we have a stage of development in each individual case of which we might almost say that the young frog has first to turn into a fish before it can become a frog.

How are we to explain this?

At first people supposed something like the following: All beings in nature are admirably adapted to their environment and their life-conditions. Whatever be the explanation of it, it is a simple fact. Now, the frog lays its eggs in the water. The young ones develop from these eggs, and find themselves in the water. The most practical adaptation for them is to swim about by means of a tail and breathe by means of gills like the fish. They do not reach land until later, and they creep on to it and have an equipment of the opposite character, with legs and lungs.

But this explanation throws no light on the question why the frog lays its eggs in the water. However, there might be some utility or other, some need for protection, for instance, in that. Let us take a few other cases.

There are several species of tree-frogs, and toads, and closely related amphibia like the salamanders, that do not lay their eggs in the water. Some of them bury them in folds of their own external skin, others (such as the Alpine salamander) retain them within the mother’s body, as the mammals do. The young animals develop there from the eggs. Even there, however, where there is no question of aquatic life, the young frogs, toads, and salamanders first assume the fish-form. The young frogs and toads have fin-like tails, and all of them have gills. There seems to be some internal law of development that forces the frog and its relatives to pass through the fish-stage in their individual evolution even when there is no trace whatever of any external utility.

Now let us examine the matter as Darwinians and believers in evolution.

There are reasons on every hand for believing that the frogs and salamanders, which now stand higher in classification than the fishes, were developed from the fishes in earlier ages in the course of progressive evolution. Once upon a time they were fishes. If that is so, the curious phenomenon we have been considering really means that each young frog resembles its fish-ancestors. In each case to-day the frog’s egg first produces the earlier or ancestral stage, the fish. It then develops rapidly into a frog. In other words, the individual development recapitulates an important chapter of the earlier history of the whole race of frogs. Putting this in the form of a law, it runs: each new individual must, in its development, pass rapidly through the form of its parents’ ancestors before it assumes the parent form itself. If a new individual frog is to be developed, and if the ancestors of the whole frog-stem were fishes, the first thing to develop from the frog’s egg will be a fish, and it will only later assume the form of a frog.

That is a simple and pictorial outline of what we mean when we speak of “the biogenetic law.” We need, of course, much more than the one frog-fish fact before we can erect it into a law. But we have only to look round us, and we find similar phenomena as common as pebbles.

Let us bear in mind that evolution proceeded from certain amphibia to the lizards, and from these to the birds and mammals. That is a long journey, but we have no alternative. If the amphibia (such as the frog and the salamander) descend from the fishes, all the higher classes up to man himself must also have done so. Hence the law must have transmitted even to ourselves this ancestral form of the gill-breathing fish.

What a mad idea, many will say; that man should at one time be a tadpole like the frog! And yet—there’s no help in prayer, as Falstaff said—even the human germ or embryo passes through a stage in the womb at which it shows the outline of gills on the throat just like a fish. It is the same with the dog, the horse, the kangaroo, the duck-mole, the bird, the crocodile, the turtle, the lizard; they all have the same structure. Nor is this an isolated fact. From the fish was evolved the amphibian; from this came the lizard; from the lizard, on Darwinian principles, the bird. The lizard has solid teeth in its mouth; the bird has no teeth in its beak. That is to say, it has none to-day; but it had when it was a lizard. Here, then, we have an intermediate stage between the fish and the bird. We must expect that the bird-embryo in the egg will show some trace of it. As a matter of fact it does so. When we examine young parrots in the egg we find that they have teeth in their mouths before the bill is formed. When the fact was first discovered, the real intermediate form between the lizard and the bird was not known. It was afterwards discovered at Solenhofen in a fossil impression from the Jurassic period. This was the archeopteryx, which had feathers like a real bird, and yet had teeth in its mouth like the lizard when it lived on earth. The instance is instructive in two ways. In the first place it shows that we were quite justified in drawing our conclusions as to the past from the bird’s embryonic form, even if the true transitional form between the lizard and the bird were never discovered at all. In the second place, we see in the young bird in the egg the reproduction of two consecutive ancestral stages: one in the fish-gills, the other in the lizard-like teeth. Once the law is admitted, there can be nothing strange in this. If one ancestral stage, that of the fish, is reproduced in the young animal belonging to a higher group, why not several?—why not all of them? No doubt the ancestral series of the higher forms is of enormous length. What an immense number of stages there must have been before the fish! And then we have still the amphibian, the lizard, and the bird or mammal, up to man.

Why should not the law run: the whole ancestral series must be reproduced in the development of each individual organism? We are now in a position to see the whole bearing of Haeckel’s idea, and at the same time to appreciate his careful restrictions of it.

First, let us see a little of the history of the matter. In the first third of the nineteenth century a number of pre-Darwinian ideas of evolution flitted about like ghosts in natural philosophy, as I have already said. The evolutionary ideas of Goethe and Lamarck are well known to-day. Another thinker of great influence was Lorentz Oken, who established the custom of holding scientific congresses. Oken had been constantly occupied with embryology, the science of the development of the individual organism. He was at all events acquainted with all that was known at the time on the subject. I open an old volume, wretchedly printed on blotting-paper, of Oken’s General Natural History for all Readers (1833), and turn to a passage in the fourth volume (the first to be issued) on page 470.

We read that the caterpillar of the butterfly resembles the animal form at a stage of development that lies below the insect—the worm. Oken says: “There is no doubt that we have here a striking resemblance, and one that justifies us in thinking that the development in the ovum is merely a repetition of the story of the creation of the animal groups.” Oken was quite aware that the chick in the egg had gill-slits like the fish. He bases his idea on that fact. He was very close indeed to the theory that Haeckel has so wonderfully elaborated. However, he was greeted with laughter. His theory was treated as an absurdity from 1833 to 1866. It cannot be denied that he was himself partly to blame for this. Oken made two serious mistakes. On both points Haeckel is perfectly clear and sound. Moreover, the theory of natural evolution that made it possible for us to speak of “ancestors” was still a Cinderella in the days of Oken. No sooner was it rehabilitated than the principle of the old theory of embryonic forms returned once more.

Darwin himself at once appealed to it, but it was reserved for Haeckel to develop its full importance. He corrected it in two particulars. Oken and his admirers had made an unfortunate mistake. They believed in a genealogical tree of all living things, but they conceived it on the lines of the old classification. Linné had enumerated in succession: mammals, birds, amphibia, fishes, insects, and worms. He put them in one straight line, which is certainly the best arrangement for general purposes. But when Oken came with the idea of natural evolution, he at once took this series as the outline of a genealogical tree. The mammals descended from the birds; the fishes from the insects; and so on. If that were really the case, the highest animals would be expected to reproduce all the animal and plant stages in the course of their embryonic development, on the lines of the theory. The human being would have to be, successively, not only a lizard and a fish, but even a bird, a beetle, a crab, and so on. This was by no means borne out by the facts, and so the theory seemed to be discredited.

Now let us glance at Haeckel’s genealogical tables. We find eight of them, artistically drawn, at the end of the second volume. The “genealogical tree” is given in the form of a branching tree, or as a huge forest-like growth of stems some of which only meet in the ultimate roots. There is no trace in Haeckel’s designs of the sort of Eiffel-Tower arrangement that the Linnean system involved. At the bottom we find the protists, the most primitive forms of life. From this point two parallel stems diverge, that of the animals and that of the plants; they never touch each other after this point, and so cannot be expected to be reproduced in the embryonic forms. Then the animal stem is split up almost at the root into at least five independent branches, each of which pursues its separate line of development. One culminates in the insects, above the worms and the crustacea. A totally independent stem issues in the vertebrates, and this in turn breaks into many different branches. Beyond the lizards, for instance, we find the development of the mammals and birds, which run on as separate and parallel lines. It was mere nonsense to expect a mammal in its embryonic development to assume the form of a bird, or a crab, or a beetle, or a mussel, or a medusa, even if the biogenetic law were established ten times over.

The second mistake made by Oken was to declare that, whatever it cost, the law must be observed everywhere. He examined the butterfly. It passed through two curious embryonic stages: first the caterpillar, then the pupa. The caterpillar corresponded to the worm; that might be plausibly contended. But the pupa also must stand for something. Between the worm and the insect in classification was the crustacean. It had a hard shell: so had the pupa. Consequently, the pupa is a reproduction of the crustacea-stage. Such were the bold chess-moves of the older theorist.

Haeckel first established that there was such a thing as the biogenetic law. There is a fundamental norm, which is made clear to us in embryology and can at the same time (remember the instance of the lizard-like teeth in the bird-embryo) give us most wonderful suggestions as to the line of ancestral development. But it has certain limitations, as we will now show.

The adaptations in the sense of the Darwinian laws have affected the animal’s embryonic life more and more, the higher the tree of life grew. The long recapitulation of the ancestral stages often came into conflict with the young individual’s need for protection. The result was that the biogenetic law found itself restricted by the Darwinian laws of adaptation. The too lengthy succession of ancestral portraits was abbreviated and compressed. Whole stages of embryonic or larval development were interpolated that had nothing to do with these ancestral portraits, but were destined for the protection of the fœtus. The butterfly-pupa is really an instructive instance of this description. It does not reproduce a crab-stage, nor has there been any stage in the ancestry of the butterfly when they lived throughout life in pupa-houses. The pupa is simply a later adaptation in the development of the butterfly, a protective stage in which it accomplishes the transition from the caterpillar-form in much the same way as the young bird develops under the protection of the hard egg-shell. Thus only a faint and shadowy trace has been left of the real ancestral forms, though this trace is an extremely instructive one. But we must not expect the impossible from it. In this way our naked and crude biogenetic law assumes a more finished and scientific form: the embryonic development of the individual is a condensed, abbreviated, and to some extent modified epitome of the evolutionary history of its ancestors. That is more modest, but it is a correct expression of the facts. The essential point of the older idea was not in itself wrong; all that was done was to explain the gaps, and leaps, and contradictions in it.

Now that Oken’s share in the theory has been properly appreciated, we may notice another little historical detail. In the period immediately after his time these ideas were ridiculed by men of science, great and small, but they were not exactly “done to death.” Agassiz, the most pronounced creationist and dualist of all the nineteenth-century zoologists, expounded them occasionally as a curious instance of the divine action. In fact, he looked upon the whole of zoology as a mystic cabinet of curiosities—the more curious the better. Thus he came to play with this idea and confirm it, but merely took it at first as a fine figure of speech. Agassiz is a tragical form. He survived Darwin, much in the same way that many an elegant mot-de-salon on the rights of man survived the French Revolution. Suddenly the whole structure of his ideas seemed to fall about him. Where he had played with roses, he now found torches. He reeled like a smitten man, and cried out against the horrid monsters that brought him pain and bitterness. His anxiety began with Darwin, even as regarded the question of the embryo. But there was another, a man far away in South America, that increased it—Fritz Müller.

Born in 1822, one of the finest pioneers in zoological work, Fritz Müller had wished to become a higher teacher, but had abandoned his plan on account of the oath that had to be taken by every servant of the State. In 1849 he wrote to the Ministry requesting that he might be allowed to dispense with the formula “So help me God, through Jesus Christ.” Meeting with a refusal, he went to South America, and began a solitary life as a student in the primitive forest, and sought to accumulate valuable zoological material. Darwin called him “the king of observers.” In 1864 he published an essay of ninety-four pages with the title For Darwin. He revived and improved the old idea of Oken’s and made fresh contributions to the natural history of the crustacea that were literally stupefying. We may say that the point that he believed he had established, in virtue of the law, in regard to the genealogical tree of the crustacea, was afterwards, with apparent justice, called into question, even by supporters of the law such as Arnold Lang. That, however, did not diminish the extent of his influence at the time. Haeckel has generously acknowledged how strongly he felt that influence himself. Nevertheless all that has been said about Haeckel’s priority in fully applying and shaping the law, and in its final formulation, is perfectly correct.

When Haeckel had massed his material he had first to create the necessary terms for arranging it distinctly. In the language of the old legend, he called the day day, and the night. To the story of ancestral development, or the evolution of the stem, he gave the name of phylogeny, or stem-history (phylon = stem). The word circulates very widely to-day. The story of the development of the individual until it reaches maturity was then called ontogeny (on = being), which coincides generally with embryology (though it may also include the growth of the child). The law then ran: Ontogeny is an abbreviated and frequently disarranged epitome of phylogeny. Special attention was drawn to the qualifications “abbreviated” and “disarranged.”

Here again two fresh names were invented. In so far as the embryonic development is a true recapitulation of the stem-history, it is called palingenesis, or repetition of the ancestral traits. When the development is altered by new adaptations it is called cenogenesis, “foreign” or “disturbing” development.

It has been objected by small-minded critics that Haeckel forces nature to mar its own work. The real meaning is quite clear if we bear in mind the blunder of Oken. In this case “disturbed development” is merely an expression of the fact that the laws we invent are ideal forms, and not always convenient realities. We learn by heart that the earth is a globe, and its orbit is an ellipse. Neither of the two propositions is strictly accurate; no mathematical figure even has objective reality. By the sheer attraction of the water of the ocean to the continents the earth has an irregularity of shape that it is barely possible to express in words. To call the path of the earth round the sun, constantly altering as it does, and still further complicated by the sun’s own movement, a real ellipse is the greatest nonsense conceivable.

In this sense every natural law is subject to disturbances, though these in turn are the outcome of natural laws. If we do not cavil over the name, we find that the idea it stands for is of the greatest consequence for any further use of the biogenetic law. Unless it is borne in mind, the law, especially in the hands of the inexpert, falls into hopeless confusion. We read so often that the ancestral history is identical with the embryonic development. The one is a recapitulation of the other. This supposed law is then applied in psychology, æsthetics, and many other directions. If it succeeds, there is jubilation. If it does not succeed (as it does not in a thousand cases), the whole blame is thrown on Haeckel. People discover that “the biogenetic law breaks down here,” and they throw over Darwinism altogether.

The second volume of the Morphology is the standing palladium against all this nonsense. It marks off the real readers and followers of Haeckel from the superficial talkers who run after him because he is famous, and will leave him unscrupulously for any other celebrity of the hour.

The book must be read. Even in this second volume an incredible amount of matter is compressed. An introduction, consisting of a hundred and sixty pages of small type, gives us an idea of the new system. This is the first scheme of a real “natural classification” of living things. From this we pass to special morphology. But this fearless sketch of the specialised genealogical tree, according to the new ideas, puts general morphology in its true light. We are made to feel that it is not all mere theory. To-morrow—nay, to-day—the whole practice of zoology and botany will have to be remodelled on the new principles. Off with the roof of the ark! The whole museum must be cleared out. We want new divisions, new labels. The old controversy between the Nominalists and the Realists seemed to have come to life once more. How students had played with the word “affinity” as a symbol. The lemurs were “related” to the apes, and to other groups of mammals. The star-fishes were related to the sea-urchins, to the encrinites. The word had, in fact, led to a certain amount of arrangement; the stuffed or dried or preserved specimens in the museum were placed side by side. Suddenly the whole thing became a reality. The things that were “related” to each other had really been connected historically in earlier ages. The lemurs were the progenitors of the apes. Behind them were a series of other mammals. Star-fishes, sea-urchins, and encrinites, formed a definite branch of the great tree, and were historically connected; not symbolically, but in a real extinct common ancestor.

It was a vast work. A single man had at first the whole kingdom in his hands, had to reject the old lines of demarcation and create new ones. There was a certain advantage at the time. Since Cuvier’s time an immense quantity of new discoveries had accumulated for the construction of a system of living things. Müller, Siebold, Leuckart, Vogt, and many others, had done a great deal of preparatory work. All this was of great assistance to the man who now came forward with courage and a talent for organisation. Nevertheless it needed real genius, together with almost boundless knowledge, to accomplish the task. We must remember how reactionary (even apart from the question of evolution) was the systematic work of distinguished and assuredly learned zoologists like Giebel at that time; they worked on in a humdrum way as if the more advanced students did not exist. How different it has all become since Haeckel’s thorough reform of classification! We are astounded to-day at the skill with which he drew lines in his very first sketch that were so near to the permanent truth. I need only point to the new scheme of the classification of the vertebrates. A good deal of his work was, of course, bound to be defective, because the facts were not yet known; for instance, in fixing the point at which the vertebrates may have evolved from the invertebrates. It was not until a year later that the discovery of the embryonic development of the ascidia by Kowalewsky threw light on this. Again, there was the solution of the problem of the ultimate root-connection of the great parallel animal stems. In this matter Haeckel himself brought illumination by his gastræa-theory.

On the whole this systematic introduction to the second volume would have sufficed of itself to secure for Haeckel a prominent position in the history of zoology and botany. He himself was chiefly proud of the fact that it was the first natural-philosophical system on the new lines to meet the rigorous demands of academic science, and indeed to revolutionise academic science. This enhances his complete triumph in the last two books of the volume. First man is introduced, with absolute clearness and decisiveness, into the system of evolved natural beings, as crown of the animal world, but subject to the same laws as the animal: a vertebrate, a mammal, whose nearest relatives are the anthropoid apes. Thus at last the “system of nature” was complete. It embodied the unity of nature. It formed the framework of facts for a unified natural philosophy, Monism. The monon, the “one,” embracing all things, that included nature in itself and itself in nature, became the last scientific definition of what people called “God.”

Thus the volume, which had begun the system of nature with the monera, closes with a chapter on the Monistic God—“the God in nature.” The conception of God in human fashion is rejected. Man is merely a vertebrate, a mammal, adapted in his whole structure to our little planet. A supreme Being to whom we ascribe omnipresence could not possibly be confined within the narrow limits of this vertebrate and mammal organisation. When we try to do so we fall into unshapely conceptions that are wholly unworthy of the most exalted of all words, ideas, and beings. It is in this connection that Haeckel uses for the first time the phrase “gaseous vertebrate,” that has so often been quoted and attacked since. He means to say that we are driven to such debasing and senseless definitions if we do not recognise in God the essence of the whole system of things; if we form our idea of him arbitrarily on any particular property of things within the system. We must beware—as he expressly says—of such confused and unworthy comparisons.

“Our philosophy,” Haeckel continues, “knows only one God, and this Almighty God dominates the whole of nature without exception. We see his activity in all phenomena without exception. The whole of the inorganic world is subject to him just as much as the organic. If a body falls fifteen feet in the first second in empty space, if three atoms of oxygen unite with one atom of sulphur to form sulphuric acid, if the angle that is formed by the contiguous surfaces of a column of rock-crystal is always 120 degrees, these phenomena are just as truly the direct action of God as the flowering of the plant, the movement of the animal, or the thought of man. We all exist ‘by the grace of God,’ the stone as well as the water, the radiolarian as well as the pine, the gorilla as well as the Emperor of China. No other conception of God except this that sees his spirit and force in all natural phenomena is worthy of his all-enfolding greatness; only when we trace all forces and all movements, all the forms and properties of matter, to God, as the sustainer of all things, do we reach the human idea and reverence for him that really corresponds to his infinite greatness. In him we live, and move, and have our being. Thus does natural philosophy become a theology. The cult of nature passes into that service of God of which Goethe says: ‘Assuredly there is no nobler reverence for God than that springs up in our heart from conversation with nature.’ God is almighty: he is the sole sustainer and cause of all things. In other words, God is the universal law of causality. God is absolutely perfect; he cannot act in any other than a perfectly good manner; he cannot therefore act arbitrarily or freely—God is necessity. God is the sum of all force, and therefore of all matter. Every conception of God that separates him from matter, and opposes to him a sum of forces that are not of a divine nature, leads to amphitheism (or ditheism) and on to polytheism. In showing the unity of the whole of nature, Monism points out that only one God exists, and that this God reveals himself in all the phenomena of nature. In grounding all the phenomena of organic or inorganic nature on the universal law of causality, and exhibiting them as the outcome of ‘efficient causes,’ Monism proves that God is the necessary cause of all things and the law itself. In recognising none but divine forces in nature, in proclaiming all natural laws to be divine, Monism rises to the greatest and most lofty conception of which man, the most perfect of all things, is capable, the conception of the unity of God and nature.”

The book closes with these words and a quotation from Goethe. It had opened with a quotation from Goethe. Goethe runs through the whole of the two energetic volumes like an old and venerable anthem. The stalwart fighter not only traces his whole Monistic philosophy to Goethe: not only owes to him the very idea of morphology. In front of the second and more strictly Darwinistic volume he has a dedication “to the founders of the theory of evolution,” and between Darwin and Lamarck we find the name of Goethe. It was Haeckel’s firm conviction that Goethe not only believed in the unity of God and nature, but literally in the natural evolution of the various species of animals and plants from each other. In this conviction, which claims Goethe explicitly for Darwin, he has never been shaken, although his own friends and convinced evolutionists (Oscar Schmidt, for instance) have often opposed him on the point.

Much has been written since the days of the General Morphology both for and against this Goethe-Darwin theory, but I cannot see that we have got much further with it. I still find that a candid study of some of Goethe’s smaller writings, such as the History of my Botanical Studies, the criticism of D’Alton’s Sloths and Pachyderms (which is very important), and several others, compels us to think that Goethe really believed, in a strikingly Darwinian way, in a slow transformation and evolution of animal and plant species in virtue of purely natural laws; and that he always laid great stress on this idea of his as an original notion, far in advance of the professional science of his time. We not only have several clear passages, but the whole point of his argument really rests on this idea. Hence, apart altogether from the pedantry that tries to make a cabalistic mystery out of Goethe’s works, and always reads B for A and C for B, it does seem that there was truth in Haeckel’s first view of the matter, in spite of all the ink that has been shed over it and the vast amount of word-splitting exegesis. Darwinism has, in a certain sense, its German side, even apart from all that Haeckel has done for it.

* * * * *

This was the book, then, that the deeply afflicted author wrung from himself as his “testament.” It was written and printed with unprecedented speed. When the first copies were issued, the author had a feeling that he had nearly “done for himself.” He could not sleep. The state of his nerves gave great concern to his friends, who were watching him most anxiously. With a stolid fatalism, as if nothing mattered now, he yielded to their pressing advice, and decided to travel for a time. Far away on the blue Atlantic, at the gate to all the glories of the tropics, there is an island, Teneriffe, that was counted one of “the isles of the blest” in the old Roman days. A huge volcano rises from it, and on its flanks we find all the zones of the geography of plants, as in a model collection. Humboldt has given us a splendid description of it, as the first station of his voyage to the tropics. “The man who has some feeling for the beauty of Nature,” he says, “will find a more powerful restorative than climate on this lovely island. No place in the world seems to me better calculated to banish sorrow and restore peace to an embittered soul.” Haeckel went there.

It was not an expensive journey, but it came as a fresh greeting from Nature. It was a new ocean after the long studies on the Mediterranean. What might it not afford in the way of medusæ and other zoological prizes when the general beauty of the landscape, that had enchanted Humboldt, had been fully enjoyed. With a mingling of his overflowing passion for Nature, and the gloomy fatalism that told him this would be his “last voyage” after his “last book,” he asked permission to leave Jena in the autumn of 1866, when the printing of the Morphology was completed, and set out. It was no more to be his last voyage than the Morphology to be his last testament. Although still subdued with resignation in his inner life, he came home in the spring of 1867 with a new elasticity of body and mind, restored by the influence of the palms and bananas and spurge, and braced for the great struggle of his life that was now to begin in earnest.

The voyage had really two aims. To see the volcano above a palm-clad coast, with the Atlantic Ocean bringing its medusæ; and to work for Darwin.

A personal connection between the two had already been formed as a matter of course. Darwin, almost confined for years to his isolated home at Down owing to his constant ill-health, had received a copy of the Radiolaria, and the correspondence had begun. The work had as yet met with little encouragement from the ranks of exact scientists. It cannot have been a matter of indifference to Darwin personally that so distinguished a work, a real model of professional research, had come over to him. Proofs of the Morphology were sent over to Down before the book was ready for publication. Darwin read German with difficulty, but in this case he was stimulated to make an unusual effort. At last Haeckel himself made his appearance at the master’s home. It seemed as though he had to visit him in person to receive his blessing. It was, at all events, a happy moment in the history of Darwinism when the two men first met whose names will be inseparable in literature.

This was in October, 1866; Darwin had sent his carriage to bring Haeckel from the station. A sunny autumn morning smiled on the homely and beautiful English landscape with its bright woods and golden broom and red erica and evergreen oaks. Haeckel has described their first meeting. “When the carriage drew up before Darwin’s house, with its ivy and its shadowy elms, the great scientist stepped out of the shade of the creeper-covered porch to meet me. He had a tall and venerable appearance, with the broad shoulders of an Atlas that bore a world of thought: a Jove-like forehead, as we see in Goethe, with a lofty and broad vault, deeply furrowed by the plough of intellectual work. The tender and friendly eyes were overshadowed by the great roof of the prominent brows. The gentle mouth was framed in a long, silvery white beard. The noble expression of the whole face, the easy and soft voice, the slow and careful pronunciation, the natural and simple tenor of his conversation, took my heart by storm in the first hour that we talked together, just as his great work had taken my intelligence by storm at the first reading. I seemed to have before me a venerable sage of ancient Greece, a Socrates or an Aristotle.”

They were delighted to meet each other, for they were like natures, in their best qualities. Darwin had more passion in him than he ever expressed, and behind all Haeckel’s impetuosity there was the naïve and yielding temper of the child. He poured out his anger against the stubborn and bewigged professors who still held out against the luminous truth of the theory of evolution. Darwin put his hand on his shoulder, smiled, and said they were rather to be pitied than blamed, and that they could not keep back permanently the stream of truth. At heart, however, he was delighted with his fiery pupil. They were to fight their battle shoulder to shoulder for seventeen years. During all those years there was never the slightest disturbance of their friendship. Darwin knew well what an auxiliary he had in Haeckel. It is true that he wrote him a wonderful letter occasionally, in which he used the right of a senior to warn Haeckel not to deal so violently with his opponents. Violence only had the effect of making onlookers side with the party you attacked. We must be careful not to be too hasty in setting things up as positive truths, as we see every day people starting from the same premises and coming to opposite conclusions. But he was generally at one with Haeckel, and had the good spirit to acknowledge it openly. When Haeckel’s History of Creation raised up the most extreme parties, and started the cry that a distinction must be drawn at once between Darwin’s real scientific ideas and Haeckel’s desperate excursions into natural philosophy, Darwin said, in the Descent of Man, which he had begun much earlier, but did not publish for some time, that he would never have written his book if he had then known Haeckel’s History of Creation. Haeckel had anticipated so much that he wished to say. And when Virchow attacked Haeckel in 1877, Darwin spoke very severely of the opponents who would make the eternal freedom to teach the truth dependent on the accidental conditions of a modern State. Haeckel visited him twice at Down. On February 12, 1882, he sent Darwin his congratulations on his seventy-third birthday from the summit of Adam’s Peak in Ceylon. This was his last greeting. Darwin died two months afterwards. There was a touch of romance in this last communication of the two great warriors. On the summit of the mountain, almost as sharp as a needle, and 2,500 yards above the Indian Ocean, a tiny temple of Buddha hangs like a stork’s nest suspended by chains. Buddha is believed to have left his footprints on the rocks here. The Mohammedan tradition, however, says it was done by Adam as he stood on one foot and bemoaned the loss of Paradise. In front of this holy trace, a depression in the rock about a foot long, Haeckel made a speech to his travelling companions, and they broke the neck of a bottle of Rhine wine to Darwin’s health. It is no little stretch of humanity’s pilgrimage, from Adam to Buddha and on to Darwin.

ERNST HAECKEL AND HIS ASSISTANT MIKLUCHO-MACLAY AT LANZAROTE, IN THE CANARIES, 1867. ]

In October, 1866, Haeckel had a companion in a teacher from Bonn, Richard Greeff (afterwards professor of zoology at Marburg). They took ship from London to Lisbon, where they were long detained for quarantine, though the annoyance was somewhat relieved by the discovery of an interesting medusa in the brackish water of the Tagus. They then went to Madeira and Teneriffe, not right into the tropics, but where they might get a breath of it, as it were. Two of Haeckel’s pupils, who both became well known afterwards, Miklucho-Maclay and Fol, were with them. Greeff has given a full account of the journey in a whole volume (published at Bonn, 1868), and Haeckel has written of it in two articles, one of which (in the fifth volume of the Zeitschrift der Gesellschaft für Erdkunde, Berlin, 1870) is a perfect masterpiece of narrative and description of scenery. After a long search they chose as the best station for studying marine animals, especially the medusæ, the little island of Lanzarote, instead of one of the chief islands. Here they fished and drew, in the manner taught by Johannes Müller, for three months, from December, 1866, to February, 1867. It is not exactly an ideal place. “Imagine yourself dumped down on the moor!” Haeckel said afterwards in his description of it. A piece of arid land that looked like a strip of the Sahara in the middle of the ocean. There is hardly any water, and the vegetation is correspondingly meagre. Across the middle of the island stretches a chain of volcanic craters, and old lava-fields run down from them as far as the coast. Everything of zoological interest in the place was to be found in the sea. There they found abundance. As in Messina, certain local currents drove the rich animal plancton together until there were literally rivers or streets of tiny animals. One had only to dip in one’s nets and glasses, and bring up whole shoals with every drop of water.

Haeckel had come chiefly to study the medusæ. But this led him on much further to a great zoological problem. In his General Morphology he had expounded his brilliant ideas on the subject of individuality, and now he encountered in the flesh one of the greatest marvels of animal individuality. He had shown how the higher individual is always made up of a community, a kind of state, of lower individuals. In the simplest instance there are the cells. Each of them is an individual. Millions of these individuals, banded together with division of labour for great collective operations, make up the human frame, and therefore the human “individual.” In the same way others form a beetle, a snail, or a single medusa. Sometimes, however, these higher individuals enter in turn into social combinations to form still higher communities. Human beings form social commonwealths, with division of labour among the individuals. Bees and ants form their communities in the same way. But in the latter cases the texture of the community seems to be much looser than in the preceding one. It is not so easy for the imagination to grasp a human commonwealth or a colony of bees as a real “over-individual.” It is, therefore, extremely instructive to find that at least one animal community of this kind is of so firm a texture that even on the most superficial examination it is recognised at once as an individual. This is found in one of the groups of the medusæ, the siphonophores, or social medusæ.

A number of single medusæ, each of which corresponds to what we regard as the individual man, combine and form a new body, a social individual. As citizens of this new state they have introduced the most rigid division of labour. One medusa does nothing but eat, and it thus provides nourishment for the rest, as they are all joined in one body. Another accomplishes the swimming movement; another has been converted entirely into a reproductive organ. In a word, the whole has become a “unity” once more, equipped with its various organs like any large body. Sometimes thousands of separate medusæ enter into the structure of one of these wonders of the deep. And as each of the medusæ is generally a very pretty, flower-like creature, the social groups with their charming colours look like floating garlands of flowers made of transparent and tinted crystal. Their beauty would soon fix Haeckel’s attention, but their bearing on his theory of individuality would give them an even greater value. For several years he had searched most attentively in the animal world for these “over-individuals” of the highest class. In the morphology he had had to be content with an old illustration of something of the kind, the star-fish. It was supposed to be a combination of vermalians. In this case the hypothesis has broken down, though there was a good deal to be said for it at first, and it was abandoned by him afterwards. But now, when he saw enormous numbers of siphonophores in the animal streams at Lanzarote, he entered upon a decisive study of the meaning of these real “social animals.” A social medusa has so great an appearance of unity that those who discovered it first did not believe it was a community, but a very complicated individual medusa. Vogt (1847) and Leuckart (1851) had denied this, and declared it to be a social group. But the controversy was still going on, as there was much difference of opinion as to the meaning of “social” and “state.” Haeckel now succeeded at Lanzarote in tracing for the first time the development of one of these siphonophores from the ovum. He was able to show that from the ovum only a single simple medusa is developed. This, then, becomes the parent of the community; it produces the rest of the members, not by a new sexual generation, but by budding out from itself, until the whole garland of connected individuals is ready to constitute the new over-individual, or the community. These luminous investigations were published three years afterwards (1869) in a work that was crowned by the Utrecht Society of Art and Science (The Embryology of the Siphonophoræ, with fourteen plates, published at Utrecht). But Haeckel returned time after time in later years to this group of animals with such great philosophic and zoological interest. When he had put before him in the eighties the whole of the siphonophores brought home by the splendid Challenger expedition, he combined the material with the results of his own studies in a fine work, which was included (in English) in the publications of the Challenger series at London, as the 28th volume of the Zoology of the Challenger, 1888. The voluminous work is illustrated with fifty masterly plates, some of them coloured, by Haeckel himself. The most important part of the text was also published in German at Jena, with the title, System of the Siphonophoræ. There is a good popular account of the siphonophore question in his lecture on “The Division of Labour in Nature and in Human Life” (1869). A few of these beautiful forms are also given on coloured plates in his illustrated work, Art-forms in Nature. Every thoughtful man ought, whatever his position is as regards Haeckel’s ideas, to glance at this material that he has so vigorously and clearly presented.

While he was conducting this research into the embryonic development of the siphonophores, Haeckel made certain experiments on phenomena that have lately been made the subject of a special “experimental mechanical embryology” by some of his pupils, particularly Professor Roux, of Halle. He cut up siphonophore ova into several pieces at the commencement of their development, and saw an incomplete social medusa develop from each fragment.

A SIPHONOPHORE (Disconalia gastroblasta.) ]

Thus the journey, like the earlier one to Messina, brought the indefatigable student into touch once more with a “philosophical animal.” This alone would have made it well worth the trouble. How many more of the kind the future might still have in reserve for him! In the quiet months at Puerto del Arrecise, on Lanzarote, he was gradually restored to his spiritual balance. Nature had taken much from him, but she offered him an inexhaustible return. His elasticity and vigour of frame had been restored before he left Teneriffe. In a twenty-two hours’ tour, only interrupted by two hours’ sleep, he had climbed to the highest summit of the Peak, in such an unfavourable season (in the November snow) that the native guides would not go any further in the end; all those who were with him except one stopped short a little way from the top. The short rest at the summit (4,128 yards above the sea-level, on the icy edge of the crater) was greatly enjoyed by him. He could see over a distance of 5,700 square miles, as much as one-fourth of the whole of Spain. “The extraordinary range and height of the horizon gives one a vague idea of the infinity of space. The deep unbroken silence and the consciousness that we have left all animal and vegetal life far behind, produce a profound feeling of solitude. One feels oneself, with a certain pride, master of the situation that has been secured with so much trouble and risk. But the next moment one feels what we really are—momentary waves in the infinite ocean of life, transitory combinations of a comparatively small number of organic cells, which, in the last resort, owe their origin and significance to the peculiar chemical properties of carbon. How small and mean at such moments do we find the little play of human passions that unfolds itself far below in the haunts of civilisation! How great and exalted in comparison does free Nature seem, as it unrolls before us, in one vast picture, the whole majesty and splendour of its creative power!” Thus he himself describes the moment. Something of that feeling of exalted solitude entered into his life. He stood firm and undazed—come what might.

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