The cover image was created by the transcriber and is placed in the public domain.

HAECKEL:
HIS LIFE AND WORK

ERNST HAECKEL.
From the Painting by Franz von Lenbach, 1899.
(Reproduced in “Jugend.”)

HAECKEL:

HIS LIFE AND WORK

BY

WILHELM BÖLSCHE

WITH INTRODUCTION AND SUPPLEMENTARY CHAPTER BY THE TRANSLATOR,

JOSEPH McCABE

WITH THIRTEEN ILLUSTRATIONS

PHILADELPHIA

GEORGE W. JACOBS & CO.

PUBLISHERS

(All rights reserved.)

Contents

CHAPTER I

CHAPTER II

CHAPTER III

CHAPTER IV

CHAPTER V

CHAPTER VI

CHAPTER VII

CHAPTER VIII

List of Illustrations

Introduction

One of the admirable maxims that crystallises the better sense or experience of men reminds us that we must “say nothing but good of the dead.” Unhappily, we have taken the words of our sage fathers in too large a sense. A feeling has grown amongst us that we should “say nothing good except of the dead,” at least as regards those who differ from us. So has many a man gone from the world with little suspicion of the appreciation that might have warmed him in the last chill years; many a man sunk into the grave with the harsh echo of dishonouring words still rumbling in his ears. It may be that our ideas, our truths, would not suffer greatly if we could patiently endeavour to trace the community of humane feeling that lies beneath the wide gulfs that often separate us intellectually from each other.

Professor Ernst Haeckel is one of those combative figures of all time who take misunderstanding as a part of their romantic career. If he had shut himself within the laboratory, as some of his gifted colleagues did, all the world would honour him to-day. His vast range of biological knowledge, almost without parallel in our specialist days, fitted him for great scientific achievements. His superb special contributions to biology—his studies of radiolaria, sponges, medusæ, &c.—give ample evidence of it. As things are, he has, Professor Hertwig says, “written his name in letters of light in the history of science.” He holds four gold medals for scientific research (Cothenius, Swammerdam, Darwin, and Challenger), four doctorates (Berlin, Jena, Edinburgh, and Cambridge), and about eighty diplomas from so many universities and academic bodies. But he was one of those who cannot but look out of the windows of the laboratory. His intense idealism, his sense of what he felt to be wrong and untrue, inflamed by incessant travel and communion with men, drove him into the field of battle. In the din and roar of a great conflict his name has passed on to a million lips and become the varied war-cry of fiercely contending parties. A hundred Haeckels, grotesque in their unlikeness to each other, circulate in our midst to-day.

The present work is a plain study of the personality of Haeckel and the growth of his ideas. The character of Haeckel was forged amid circumstances that have largely passed away from the scientific world of our time. The features, even, of the world he has worked in of recent years in Germany are so different from our own that no Englishman can understand him without sober study of his life. He has often been called “the Darwin of Germany.” The phrase is most misleading. It suggests a comparison that is bound to end in untruth and injustice. In the same year that Haeckel opened his Darwinian campaign in Germany he won the prize for the long jump—a record jump. It is the note of much in his character. He was no quiet recluse, to shrink from opposition and hard names, but a lusty, healthy, impetuous, intrepid youth, even when his hair had worn to grey. A story is told of how, not many years ago, the Grand Duke of Weimar playfully rallied him, in the midst of a brilliant company, on his belief in evolution. To the horror of the guests, he slapped the powerful noble on the shoulder, and told him to come to Jena and see the proofs of it. In his seventy-first year we find him severely censuring his Emperor—the emperor of many fortresses—in a public lecture at Berlin.

How his vigour and his resentment arose as barrier after barrier was raised before him: how his scorn of compromise was engendered and fed: how he accumulated mountains of knowledge in obscure, technical works before he formulated his sharp didactic conclusions: all this is told in the following story. For good or ill he has won an influence in this country, and his story should be read. It is, in itself, one of rare and varied interest, and it is told by one of the most brilliant penmen of modern Germany, his former pupil, now a distinguished biologist, Professor Wilhelm Bölsche.

The time seems to have come in England for the publication of some authoritative picture of the great biologist and controversialist. One work of his circulates by the hundred thousand amongst us, and has had a deep and lasting influence on the thoughts of large classes of men. His influence is hardly less in France and Italy, as well as in Germany; his doctrines have, in fact, been translated into fifteen different tongues. The deep, sometimes bitter, controversy that they have engendered must have led to a desire to know more of the man and his making. The attempts that have been made here and there to “construct” him from his ideas and literary manner are, as the reader will see, very far removed from the reality. Behind all the strained inferences from doctrines, behind all the dishonouring epithets, there is a genial, warm, deeply artistic, intensely idealist nature, sung with enthusiasm by poets who have known him. Once, in playful scientific mood, Haeckel tried to explain his own character in his familiar terms of heredity and environment. He came of a line of lawyers, straight, orderly, inexorable men. He had lived and worked in quiet Jena, in the beautiful valley of the Saale. But he did not speak of that larger environment—the field of battle, stretching far away, beyond the calm Thuringian hills, to the ends of Europe. We must place Haeckel’s ardent and high-minded nature in that field, face to face with his opponents, if we would understand him.

For the supplementary chapter I have drawn freely on another biographical sketch by one of Haeckel’s pupils, Dr. Breitenbach, and other sources. For the illustrations I am indebted chiefly to Professor Haeckel himself, and can only offer him in return this grateful effort to lift his inspiring and impressive personality above the dust and cloud of a great controversy.

JOSEPH McCABE.

CHAPTER I
EARLY YOUTH

“I am wholly a child of the nineteenth century, and with its close I would draw the line under my life’s work.” Thus does Professor Haeckel speak of himself. There is a note of gentle resignation in the words, but the time is coming when men will give them a different meaning. Whatever greater achievements may be wrought by a future generation in the service of truth and human welfare, their work will be but a continuation of the truth of our time, as long as humanity breathes. On the intrepid, outstanding figures of the nineteenth century will shine a light that is peculiarly theirs, an illumination that men will dwell on for ever—as we look back, in personal life, on the young days of love. It was a strong love that brought our century to birth.

The soul of humanity has for four centuries been passing through a grim crisis.

Let us imagine ourselves for a moment before the noble painting by Michael Angelo in the Sistine Chapel at Rome. What art! What utter revelation of the power of man’s mind! But, we ask, what material did the genius of humanity choose in those days for the manifestation of its giant power? The last judgment: the Christ descending at the blare of the last trumpet, to reward the faithful and banish the sinner into everlasting pain: the Almighty, breathing His spirit into Adam, or mystically upbuilding Eve from the rib of the man. There was no “symbolic” intention in the picture; the deepest feeling of hundreds—nay, thousands—of years was embodied in it. The artist merely gave an imperishable external form to the most treasured truth of his time.

Yet, slowly and gradually, what a mighty change has come about!

Columbus has sailed over the blue seas, and a new side of the earth lies in the violet haze of the dawn. Copernicus sees the ball of the earth roll round the sun through space, by force of some mysterious law. Kepler dreams of the world-harmony that will replace the ever-acting Deity, and discovers at length an unsuspected regularity in the framework of the heavens. Galileo turns his new optic tube to the stars, and at once the heavens are changed, not only for the calculating, mathematical mind, but even for the eye of sense: there are jagged peaks on the moon, satellites circling about Jupiter, a wilderness of stars lying across the Milky Way, spots on the sun, rings round Saturn. Giordano Bruno shatters the ancient crystalline vault of the firmament; every “fixed star” in the Milky Way is to him a flaming sun, the pulsing heart of a whole world, in which, perchance, human hearts like ours throb and leap on a hundred planets. The red, murderous flames of hate close over Bruno, but they cannot dim the light of the new stars. It is in the eye and the brain of the new men that arise, and will nevermore fade from them.

The seventeenth century, opening amid the last glare of the martyr-fires, quickens with a vague yearning and expectation.

In the eighteenth century the old world breaks up. From the new stars, from the new world, new ideas come. On all sides is the crash and roar of conflict. Dread flames break out in the social, moral, and æsthetic life of men. But the century ends in the birth of a greater artist than Michael Angelo.

Goethe, on the morn of the nineteenth century, paints a new Sixtine Chapel in his poetry. But he no longer depicts the old ideas. He speaks of God-Nature. To him God is the eternal force of the All. His thoughts turn no longer on Creation and the Last Judgment. An eternal evolution is the source of his inspiration. He regards the whole universe as a single, immeasurable revelation of spirit. But this spirit is the rhythmic outflow of infinite developments. It becomes Milky Way and sun and planet, blue lotus-flowers and gay butterfly. At last it takes the form of man, and reads the stars as an open book. In Homer and Goethe it directs the style and the pen; in Michael Angelo and Raphael it guides the pencil and the brush.

All this unfolds in Goethe, as in a vision with yet half-opened eyes.

Then the nineteenth century begins. Nature is its salvation, the salvation of its most practical, most real need. It must struggle for its existence, like any other century, but it has new and improved weapons for the struggle. All the earlier ages were but poor blunderers. The lightning flashed on the naked savage, and he fell on his knees and prayed, powerless as he was. In the eighteenth century it dawned on men’s minds that this might be some force of nature. The nineteenth century sets its foot on the neck of the demon of this force, presses him into its service, plays with him. Its thoughts and words flash along the lightning current, as if along new nerve-tracks, that begin to circle the globe. Man becomes lord of the earth, from the uppermost azure down into the dark, cold abysses of the ocean, from the icy pole to the burning tropical desert. And at length man turns his thoughts upon himself.

Man, his arm resting on the splendid instruments of modern research, raises his hand to his brow, and turns philosopher. He becomes at once more bold and more modest than ever.

What Goethe had seen in vision rises before him now in sharp, almost hard outline from his own real life-work. He has succeeded in bringing nature and its forces to his feet, because it was flesh of his flesh and blood of his blood. He is its child. A thousand tongues proclaim the truth to him, a naïve, almost simple, revelation of reality. He digs in the earth, and ancient bones and skulls tell him vaguely of the past. Such once was he, devoid of civilisation, at the verge of the animal world. He searches his frame through and through for further light. There is the brain, where the thoughts crowd together. There is the cell, that builds up the whole body, the cell that so closely resembles the lowest of all living things, not yet distinct enough to be either animal or plant. Here are the forms that he successively assumes in his mother’s body, before he is born—forms that can hardly be distinguished from those of the animal at the same stage of development. From almost divine heights he has sunk down to the beast, to the primitive cell—nay, deeper still, to the elementary, force-impelled matter of the universe.

But this early picture dissolves at once in an ennobling and inspiring truth. Nature becomes man. In this he presses once more to the heart of the most-high. Nature is God. Goethe sang of God-Nature. The new God pulses in every wave of man’s blood. In Michael Angelo’s picture God breathes his spirit into Adam. The new Adam of the nineteenth century is God’s spirit, in body and soul, from the very first, for he is Nature. He needs no more. When he looks up to the shining stars, he looks into the eyes of God and his own. He has come down from those stars like the bright dew in which they are now mirrored. He belongs to them, but they also are in him. All-Nature: and he is a part of Nature. All-development: and he is a phase of the development.

That is the great philosophical dream of the nineteenth-century worker. His hand is black with labour, but his spirit is full of light, the light of the stars and of the world.

No one can understand the greatness of a man like Ernst Haeckel who has not learned this melody. Nature is not a flat surface: it is an ocean. When Columbus crossed the seas in his three frail barques long ago to seek a new world in the distant haze, he little dreamed that the gray waters buried other new worlds a thousand yards beneath his keel—worlds of the deep-sea, into which our age has slowly dipped with its dredges. So we in turn may run our eye over the blue surface of nature, and think of its mysterious gold-lands and spice-islands, without suspicion of all that outspreads beneath our keel. Yet that glorious day on which Columbus found “his land” is an inspiration to us, his remote grandchildren. The life we are going to examine will bring before us such a morning of discovery. Columbus went in quest of Zipangu (as he called Japan), and he found America. Not one of us, however gifted he be, can be quite sure that, in leading humanity, he is not sailing into another such heroic error. Let us say that at once to all, friends and opponents. America or Zipangu—let it be so. Perhaps any man might have found Zipangu, while only the genius could reach America.

When Gustav Freytag, who had a most happy quality for writing memoirs, was composing his admirable Pictures from the Past of Germany, he sought in each period some prominent man of plain and downright character, yet who had something typical of his age in his sentiments, as if the time-spirit spoke through him. In this quest he twice (in the fourth volume, for the period from the close of the eighteenth century to the Wars of Freedom) lit upon earlier members of Haeckel’s family. The first was Haeckel’s grandfather on the mother’s side, Christoph Sethe; the second was his father, Councillor Haeckel.

This simple fact shows the stuff of Haeckel’s race. The older Sethe was an important man in his time. He left to his children manuscript memoirs of his eventful life, which have, unfortunately, been only sparsely used by Freytag, though the whole deserved to be regarded as a source of history. The general facts in relation to him were collected by Hermann Hüffer, who was not merely interested in the jurist because he was one himself, but was brought into touch with him as a result of his brilliant study of Heine. Sethe’s eldest son, Christian, the uncle of Ernst Haeckel, is the well-known friend of Heine’s youth to whom the poet dedicated the “Fresco-sonnets” in his Book of Songs and wrote the finest of his early letters. This Christian Sethe (he died on May 31, 1857, being then Provincial Director of Revenue at Stettin), was a lawyer, like his father, and the father himself came of a legal family. Haeckel’s own father, moreover, the husband of one of Christian’s sisters, was a State Councillor at the time of his death, and his elder brother was a Provincial Councillor. Thus Haeckel’s genealogical tree spreads into the legal profession in a curiously complex way.

We naturally reflect for a moment if we could fancy Haeckel himself as a lawyer. It is hardly possible. He would at least have been a very rebellious member of the profession, and have been sadly lacking in respect for the venerable traditions and powdered wigs of the court—assuming, of course (which a mere layman has no right to question), that there ought still to be such traditions and costumes in the profession. In his vigorous Riddle of the Universe he has, from his scientific point of view, brought strictures against the legal profession that leave nothing to be desired in the way of candour, when we recollect the long tradition of his family. In its lingering in the rear of the progress of the times the whole science of law seemed to him to be a “riddle of the universe.” The jurist is apt to be respected as an embodiment of our highest culture. In reality that is not the case. The distinctive object of his concern, man and his soul, is only superficially studied in the preparation for the law, and so we still find amongst jurists the most extraordinary views as to the freedom of the will, responsibility, and so on. “Most of our legal students pay no attention to anthropology, psychology, and evolution, the first requisites for a correct appreciation of human nature. They ‘have no time’ for it. It is unfortunately all absorbed in a profound study of beer and wine and the ‘noble art’ of fencing; and the rest of their valuable time is taken up in learning some hundreds of paragraphs from the books of law, the knowledge of which is supposed to qualify the jurist to fill any position whatever in the State.”

The student of psychology, however, cannot fail to see that the disposition that led so many members of Haeckel’s family into the legal profession was also developed in himself to some extent. There is perhaps no other scientist of his time with such an imperious craving for clearness, for clean lines and systematic arrangement. At least in the whole of the Darwinian period no other has made so great an effort to convert the scattered flight of phenomena in the realm of life into the even course of so many fixed “laws.” In many of his writings this tendency to formulate laws is so pronounced that the layman instinctively has an impression of dogmatism on the part of the author. This has been grossly misunderstood, and made to play an important part in the controversial work of his opponents. The truth is that this sharp outlook and pronounced tendency to formulate clear and unambiguous “laws” in the animal and plant worlds is a matter of temperament as much as of judgment. It is very possible that we have here an hereditary trait, an innate aversion for disorder and confusion—for a thoughtless rushing ahead without clear ideas and plan. The trait was the more important and helpful as a man of Haeckel’s type was sure to be one of the most active revolutionaries in his science, even apart from Darwinian ideas. It would be difficult to find another reformer in any great province of thought who, immediately after effecting a complete overthrow of the older ideas, has hastened so quickly to build up the new, to devise a nomenclature and a classification down to the smallest details, and hand on at once to his successors a splendid order once more. Zoology, which seemed to crumble into chaos after Darwin’s victory and the collapse of the old framework, came out of Haeckel’s hands, after barely two years’ work, in the shape of a new and graceful Darwinistic structure—not, indeed, perfect and finally completed, but entirely habitable for the young generation. They could add new stones as they thought fit, or pierce new windows, and so on; but at all events the chaos was terminated at a critical moment by this iron man of order. I will only add, to complete the picture, that one of the three doctorates that Haeckel holds to-day is that of law (an honorary degree), in addition to his qualifications in philosophy and medicine. He now only lacks the theological degree, but I fear that he will neither take the trouble to secure it nor have it conferred on him as an honorary distinction for his merit in that department.

The Sethes and Haeckels of the earlier generation were not merely zealous jurists, but also characteristic figures of Napoleonic and post-Napoleonic Prussia. Christoph Sethe, the patriarch of the maternal line, was Privy Councillor of the Prussian Government at Cleve at the beginning of the last decade of the eighteenth century, though he was then young. When the French occupied the country he accompanied the Government to Münster, in 1802, which had become a Prussian town. But the stalwart German was pursued even there by the detested Napoleonists. He was sent to Düsseldorf as General Procurator in 1808, and came into dangerous conflict with the French authorities shortly before the Emperor’s fall. The mobilisation of the troops for the campaign of 1812 had led to a disturbance amongst the workers. Sethe’s sense of patriotism and justice was affronted by the arbitrary proceedings of the French. He was summoned to give an account at Paris, the chief object being to retain him—the most powerful official in the Rhine district and not a very safe man—as a hostage during the crisis. It was at Paris that he made the finest phrase of his life. Roederer, the minister, tried to intimidate him with the threat that the Emperor might have a dangerous man like him shot at any moment. “You will have to shoot the law first,” replied Sethe. We are often reminded of this saying in the biography of Sethe’s grandson. If Haeckel had been burned at the stake like Giordano Bruno, he would have thought of nothing but the “law”—the law of truth and freedom that they would burn with him.

Christoph Sethe continued to play an important part in the service of Prussia, to which, of course, he returned, together with the Rhinelands, after Napoleon’s fall. He was destined to live through the terrible reaction under Frederic William the Third, and the fiery outburst under his successor. After the early death of his wife their youngest daughter, Bertha, managed his house and large family.

She lived until her death (April 1, 1904) in her quiet, unpretentious home in one of the large empty streets behind the Tiergarten at Berlin, reaching the age of ninety-two, but never losing her freshness of mind and memory. In my many happy talks with the aged lady the succeeding periods seemed to melt together. The small, old furniture and the ancient, ever-ticking clock made me forget, in dreamy twilight hours, that the red glare in the sky above the houses beyond, that faintly lit up the old-time room, was the reflection from the twentieth century of the electric flames that flashed on the great modern city. On the table lay the latest part of Haeckel’s (her nephew) fine illustrated work for artistically minded scientists and scientifically minded artists—the Art-forms in Nature. The dear old lady spoke with pride of her knowledge of the “radiolaria,” the mysterious unicellular ocean-dwellers, described in Haeckel’s splendid monograph, the flinty shells of which are amongst the finest artistic treasures of nature. She called them the “dear radiolaria” with all the tenderness of the emotional man of science who had felt a sort of psychic relation, a living affinity, to the tiny microscopic strangers he had been the first to arrange and describe in their thousands. Smiling, with quiet pride, she told me how her nephew visited her, when he came to Berlin; how, with the unassuming ways of this sound stock, he chose to sleep in the clothes-drying loft; how he invited his friends to come and hear of his voyages and work, bringing thirty of them to share a single dish of herring-salad in his naïve way, and how, as they continued to pour in, he made seats for them of boards and tubs, and fed them with his wonderful genius for anecdote so that none went away fasting. She dwelt with entire satisfaction on the last, the “zoological” phase, of the Haeckel-Sethe house. Yet it all blended softly with the old and the past of nearly a century ago. Over the patriarchal furniture hung the oil painting of Christoph Sethe, with the large Roman nose that runs through the family down to Ernst Haeckel himself, and gives the chief feature to his otherwise soft profile. Under a glass shade, in the old fashion of our grandfathers that we perhaps do not sufficiently appreciate, was a fine bust of Schleiermacher. He was a friend of the Sethes. Bertha Sethe was confirmed by him. He died four days before Ernst Haeckel was born, on February 12, 1834. The sister came from the grave to attend the mother of the new-born child. A little fact of that character seems to pour out a broad stream of light. The religious sense was strong in the Sethes, but it was not of the rigid conventional character. It came from the depths of human destinies, of individual experience. In those depths it is always found associated with that other fundamental quality of human experience and inner life—a zeal for the truth. Schleiermacher, the Good, had endeavoured within the limits of his time (if not of our time) to erect a new and firmer Christendom. Darwinism might very well have adjusted itself to this new Christendom, that needed no record of miracles from disputed historical works to support it, but sought the holiest ideal prophetically in the symbolic conception and the development of the true, the good, and the beautiful. Had Schleiermacher read the Natural History of Creation, or later theologians shared his temper, one wonders how much exaggeration and bitterness might have been spared on either side. But religion was not prepared to dissociate itself from “the Church,” and with the Church there could be no compromise. Thus one’s thoughts travelled from the radiolaria in Haeckel’s latest publication and the old bust of Schleiermacher, which was protected by its glass shade, in this home of old-world piety, from the wicked flies of the twentieth century.

An elder sister of Bertha Sethe and daughter of the old Christoph Sethe had married the much older lawyer, Karl Haeckel, in the twenties. The first-fruit of this marriage was Ernst Haeckel’s elder brother, the Provincial Councillor Haeckel who died a few years ago, a high-minded and sensitive man. He remained throughout life faithful to the strict traditional forms of religious experience, in spite of all his admiration for his gifted zoological brother.

The second and last child did not appear until ten years later. Ernst Haeckel was born on the 16th of February, 1834, shortly after the death of Schleiermacher, as I have explained. Most of what I know of his earliest years was told me by his venerable aunt Bertha.

His father died long ago, in 1871. Gustav Freytag has pointed out how eagerly he drank in the morning air of the dawning freedom before 1813. For many years he was at a later date a very close friend of Gneisenau. He was an earnest, conscientious, upright man, with no particular artistic arabesques to his life, and at the same time no errors. The victories of 1870 lit up the red sunset of his days. He was one of those happy folk who thought that all was accomplished in the great achievements of those days, and had little suspicion of what was still to come. The mother survived him for many years. Her son’s Indian Travels was dedicated to her on her eighty-fourth birthday, November 22, 1882. The dedication ran: “Thou it was who from early childhood fostered in me a sense for the infinite beauties of nature: thou hast ever watched my changeful career with all the ceaseless care and thought that we compress in the one phrase—a mother’s love.”

Ernst Haeckel was born at Potsdam, but in the same year the father was transferred to Merseburg, where the child was brought up. It was not his destiny to be a child of Berlin. Saxony remained essentially his home in many respects. We can always see in him something of this home that looks down on its children from its great green hills. The cold lines of the streets of the metropolis and the melancholy of the Brandenburg pine-forests cannot be traced in him. In later years Berlin assumed more and more in his thoughts the shape of an antipodal city. His works are full of the sharpest strictures on Berlin science. It was at an earlier date the city of Ehrenberg and Reichert, whom he did not love; later it was associated with Du Bois-Reymond and Virchow, who gradually became his bitterest opponents. But he detested it generally as the home of Privy Councillors, of science in the Procrustean bed of official supervision. When he compared what he himself had done at Jena with the slenderest possible appliances, and what, in his judgment, had been done by the heads of the Berlin schools in their princely institutes, he would humorously—though it has been taken very seriously—lay down the “natural law” that the magnitude of the scientific achievement is in inverse proportion to the size of the scientific institute. The official people at Berlin did not fail to make a biting retort to these Radical strictures—that in 1881, when he wanted to go to Ceylon, he was formally refused assistance by the Berlin Academy from the travelling-fee (then at liberty) attached to the Humboldt foundation. He made the journey without their assistance, and had the splendid revenge of giving us, in the description of this very voyage, the most brilliant account of the tropics that has appeared in Germany since the time of Humboldt. It was a finer contribution to the general ideal of the Humboldt foundation than the timid payment of a hundred pounds could have secured. However, we are anticipating. Before that time he was to spend a short but happy period at Berlin in the fifties, in the best days of his youth—a Berlin of a different scientific character from the present city, being at once less pretentious and more profound, whichever the reader chooses to dwell on.

Certain traits could be recognised unmistakably in the boy. He had a great love of nature, of light, colour, and beauty, of flowers and trees and butterflies, of the sun and the blue heavens. There was also a strong sense of independence and individuality. This did not imply that he was lacking in gentler feeling. It is said that he would do anything that he was asked but nothing that it was sought to compel him to do. The little fair, blue-eyed lad would sit quietly if they gave him a daisy to pull to pieces. First he would, as if he were a student analysing it, detach the white leaves from the central yellow ground. Then he would carefully replace them, piece by piece, round the yellow centre, clap his little hands and cry out, “Now it’s all right again.” It is a very pretty trait that tradition has preserved. In the play of the child we seem to see the chief lines of the man’s character like two branches of a tree; the analytic work of the scientist and the reconstructive tendency of the artist who restores the dissected world to harmony.

His excellent training in those early years fostered his feeling for nature and his sense of independence with wise adaptation to the personal character of the boy. The mother gladly cultivated his love of nature. On the deeper development of his character a decisive influence was exercised, with every regard for freedom, by a friend of the family, the physician Basedow. His ideal was education without compulsion, by means of a sort of constant artificial selection and cultivation of the good that grew up spontaneously in the soul of the child. The father, a great worker, was content to give a word of praise occasionally; to urge him to go to the root of things always, and never to coquet idly with his own soul. If the young dreamer stood at the window and looked up at the clouds, his father would pat him on the shoulder and say, “Every minute has its value in this world. Play or work—but do something.” It was, in a sense, the voice of the restless nineteenth century itself that spoke. The whole life of the youth and the man was to be an eternal proof that he had heard the message. He has pressed unwearyingly forward, as few other men have done. There was ever something in him of the mountaineer, hurrying on and watching every hour that he may reach the summit. The day of rest may come afterwards, down below in the valley. In truth, it never came. It is well known that the man wrote some of his most difficult, most widely read, and most controverted works subsequently in a few months, encroaching upon his night’s rest until his health was endangered. In a remote Cingalese village in Ceylon, where the enervating tropical climate forces even the strongest to indulge in the afternoon siesta, he tells himself that, in view of the great expense of the journey, each day is worth a five-pound note. He refuses to sleep long hours or take the siesta, rises at five in the morning, and uses the hottest hours of the day, from twelve to four, for “anatomical and microscopic work, observing and drawing, and for packing up the material collected.” He met to the full the claim of the nineteenth century, for all the inner poetic tendency of his character. Such a character he must have had to become a philosopher, as he has done; but it lay, as it were, in deeper recesses of his being. To the eye of the observer he seemed to be ever rushing on with a watch in his hand until old age. When we think of the enormous number of problems and the vast range of interests that brought him into the front rank in the nineteenth century, we may say that he advanced at a pace that would have given concern to the aged adviser of his youth in his small world.

In the long run we may say of all education as of the physician in the old saying, “The best doctor is the one we don’t need, because we are not ill.” Haeckel was sent to the school at Merseburg. This instruction came to a close in his eighteenth year. He thought of some of his old teachers with affection forty years afterwards. On the whole his later opinion of the usual schooling was as severe as that of many of his contemporaries. In his General Morphology (1866), his most profound work, he speaks of the “very defective, perverse, and often really mischievous instruction, by which we are filled with absurd errors, instead of natural truths, in our most impressionable years.” Sixteen years afterwards (in a speech delivered at Eisenach) he hopes that the triumphant science of evolution “will put an end to one of the greatest evils in our present system of education—that overloading of the memory with dead material that destroys the finest powers, and prevents the normal development of either mind or body.” “This overloading,” he says, “is due to the old and ineradicable error that the excellence of education is to be judged by the quantity of positive facts committed to memory, instead of by the quality of the real knowledge imparted. Hence it is especially advisable to make a more careful selection of the matter of instruction both in the higher and the elementary schools, and not to give precedence to the faculties that burden the memory with masses of dead facts, but to those that build up the judgment with the living play of the idea of evolution. Let our tortured children learn only half what they do, but learn it better, and the next generation will be twice as sound as the present one in body and soul. The reform of education, which, we trust, will be brought about by introducing the idea of evolution, must apply to the mathematical and scientific, as well as the philological and historical sections, because there is the same fault in them all, that far too much material is injected, and far too little attention is paid to its digestion.” Seventeen years later again, in the Riddle of the Universe, the elementary schools are severely handled. Science is still the Cinderella of the code. Our teachers regard it as their chief duty to impart “the dead knowledge that has come down from the schools of the Middle Ages. They give the first place to their grammatical gymnastics, and waste time in imparting a ‘thorough knowledge’ of the classical tongues and foreign history.” There is no question of cosmology, anthropology, or biology; instead of these “the memory is loaded with a mass of philological and historical facts that are quite useless either from the theoretical or the practical point of view.” In these expressions, which recur constantly throughout the whole of a thoughtful life, we can clearly see a very intense general experience of youth, and this is a more valuable document than any individualised complaint against this or that bad teacher in particular.

However, Haeckel (who, in point of fact, took everything seriously and would have all in the clearest order) made a very thorough appropriation of his Latin and Greek. When the new Darwinian zoology and botany needed several hundred new Latin-Greek technical terms in after-years, he showed himself to be an inventor of the first rank in this department. No other scientist has made anything like the same adroit use of the classic vocabulary for the purposes of the new system and created a new terminology for the entirely new science. His creations were certainly ingenious, and not without grace at times; in other cases, as was almost inevitable, they were less pleasing. And to this we must add thousands of names of new species which he had to coin, as the discoverer of radiolaria, medusæ, sponges, &c. In the radiolaria alone he has formed and published the names of more than 3,500 new species. I fancy that even the oldest pastor of the most fertile congregation has never conducted so many christenings. In each case it was necessary to impose two names, the generic and specific. We may well expect to find a few that will not last, but the reader is amazed at the philological creative power of this busy godfather and the inexhaustibility of his vocabulary; they show far more than the usual training in humanities.

His real predilection was pronounced enough in those early years. It was what the classical pedagogue would regard as child’s play and waste of time—zoology and botany. A large double window in his parents’ house was fitted up as a conservatory, and plants were gathered very zealously. His love of botany was so great that any one would have pronounced him a botanist in the making. But fate determined that he was to be a zoologist. In his eleventh year the boy, while paying a visit to his uncle Bleek (a professor of theology!) at Bonn, spent a whole day searching the remotest corners of the Siebengebirg for the Erica cinerea, which he had heard could not be found in any other part of Germany. At the Merseburg school he had two excellent teachers, Gandtner and Karl Gude, who fostered his inclination, and changed it from a mere collector’s eagerness into the finer enjoyment of the scientific mind. The young student wrote a contribution to Garcke’s Flora Hallensis. The professional decision gives many a troubled hour.

It is significant to find that as the novice tended his herbarium it dawned on him that there was a weak point somewhere in the rigid classification given in the manuals of botany. The books said that there were so many fixed species, each invariably recognisable by certain characters. But when the youth tried to diagnose his plant-treasures in practice by these rules, there seemed to be always a few contraband species smuggled in, like the spectres in the Wahlpurgis night to which the sage vainly expostulates, “Begone: we have explained you away.” Often the individual specimens would not agree with the lore of the books. There were discrepancies; sometimes they cut across one type, sometimes another, and at times they shamelessly stretched across the gap between one rubric and another. What did it mean? Were there really no fixed species? Was “species” only an idea, and was the reality of the plant-world in a state of flux like the sea? Teachers and books insisted that the “species” is, in its absolute nature, the basis of all botanical science, the great and sacred foundation that the Moses of botany and zoology, Linné, had laid down for ever. How could it be so?

The mature worker would look back on this dilemma of his youth with a smile of satisfaction thirty years afterwards. He would know then what sort of a nut it was that he was trying to crack in his early speculations. It was nothing less than the magnificent problem that presented itself to Darwin, the crucial question of the fixity or variability of species. “The problem of the constancy or transmutation of species,” he wrote, “arrested me with a lively interest when, twenty years ago, as a boy of twelve years, I made a resolute but fruitless effort to determine and distinguish the ‘good and bad species’ of blackberries, willows, roses, and thistles. I look back now with fond satisfaction on the concern and painful scepticism that stirred my youthful spirits as I wavered and hesitated (in the manner of most ‘good classifiers,’ as we called them) whether to admit only ‘good’ specimens into my herbarium and reject the ‘bad,’ or to embrace the latter and form a complete chain of transitional forms between the ‘good species’ that would make an end of all their ‘goodness.’ I got out of the difficulty at the time by a compromise that I can recommend to all classifiers. I made two collections. One, arranged on official lines, offered to the sympathetic observer all the species, in ‘typical’ specimens, as radically distinct forms, each decked with its pretty label; the other was a private collection, only shown to one trusted friend, and contained only the rejected kinds that Goethe so happily called ‘the characterless or disorderly races, which we hardly dare ascribe to a species, as they lose themselves in infinite varieties,’ such as rubus, salix, verbascum, hieracium, rosa, cirsium, &c. In this a large number of specimens, arranged in a long series, illustrated the direct transition from one good species to another. They were the officially forbidden fruit of knowledge in which I took a secret boyish delight in my leisure hours.”

These little scruples, however, did not interfere with what he felt to be the chief interest of botany. The collecting of plants harmonises well with a general love of nature and a passion for wandering over hill and valley. Long walks had already become a feature of his life. The scientific interest made it superfluous to have a companion. Botany went with him everywhere as his lady-love, and remained ever faithful to him. “I have preferred to travel alone most of my life,” he used to say to me; “I never feel ennui when I am alone. My love of and interest in nature are much better entertainment than conversation.” One of the features in this interest at all times, even in later years, was botanical research. The material for it is found everywhere. Darwin, a great traveller with an unusually strong appreciation of good scenery, has said that the traveller who would combine the pursuit of knowledge with æsthetic satisfaction must be above all a botanist(in the closing retrospect of his Naturalist’s Voyage Round the World, one of the finest passages in the work). Whenever Haeckel spoke in later years of his adopted Jena, he never failed to explain, amongst the other excellent qualities of the little university town, that so many fine orchids grew in its woods. When he left Jena to make the long voyage to Ceylon, his last look was at the drops of dew that sparkled like pearls “in the dark blue calices of the gentians, with their tender lashes, that so richly decked the grass-covered sides of the railway cutting.” The Letters from India, that described his voyage, owes a good deal of its peculiar charm to his skill in botanical description. I know no other work that approaches it in conveying so effective an idea of the luxuriant vegetation of the tropics.

In those early years there was one particular point of close union between botany and the sense of beauty. It was only two years before Haeckel’s birth that Goethe, the man who had put into inimitable verse new and pregnant truths of botany, passed to his rest at Weimar.

It is no longer a special distinction of any prominent personality of the nineteenth century to have been influenced by Goethe. It is a kind of natural necessity from which one cannot escape. All that is great in the century can be traced back to Goethe. He flows beneath it, like a dark stream through the bowels of a mountain. Here and there the flanks open and the stream becomes visible; not a restless bubbling spring, but a broad mirror. There is, however, a closer following of Goethe. There are a few strong spirits that have been consciously inspired by him from the first in all their thoughts; have throughout life felt themselves to be the apostles of the “gospel of Goethe”; and in every new creation of their own have held that they did but reflect or expand his ideas, did but carry on his principles to these further conclusions. Haeckel is, in his whole work, one of this smaller band; his whole personality is, in fact, one of its most conspicuous manifestations in the second half of the century.

In Goethe we find the basic ideas of his philosophy. Goethe took from him his God, and gave him a new one: took from him the external, transcendental God of the Churches, and gave him the God that is in all things, in the eternal development of the world, in body and soul alike, the God that embraces all reality and being, beside whom there is no distinct “world,” no distinct “sinful man,” no special beginning or end of things. When Haeckel found himself, at the highest point of his own path, by the side of Darwin, he was the first to see and to insist that Darwin was but a stage in the logical development of Goethe’s ideas.

Fate decided that Haeckel should be even externally in some sense an heir of the Goethe epoch. Jena, the university that Goethe had regarded with such affection, and at which Schiller had toiled with his heart’s blood in “sad, splendid years,” owes its fame in the last third of the century to Haeckel. It is not an excess of adulation, but a simple truth, to say that among the general public and abroad the reputation of Jena passes directly from Goethe, Schiller, and Fichte to Haeckel. His name stands for an epoch in the life of Jena, like theirs; all that lies between is forgotten and unknown. In the district itself it is as if the old epochs and the new came into direct touch.

Jena.
From “Jena in Wort und Bild” (Frommann’sche Hofbuchhandlung, Jena).

I shall never forget the hour when this thought came upon me in all its force. It was on a snowless December day, when the dying fire of autumn still lingered on the trees and bushes where the blackbirds sang in front of the observatory. The table and seat of sandstone stood out bleakly. A tablet indicated, in phrases of Goethe’s, that Schiller had dwelt there. It was there that the Wallenstein was born. There the two often sat in conversation—the conversation of two of the greatest minds of the time, each in his way a master spirit. To-day the little dome of the observatory looks down on the spot; it is not a luxurious building, but it is a stage in the onward journey, a symbol of the nineteenth century as it leaps into the twentieth. A little farther off rises the modern structure of the Zoological Institute. In Goethe’s day no one dreamed that such a building would ever be seen. It was opened by Haeckel in 1884. The zoological collection it houses was chiefly brought together under his direction. Amongst its treasures are, besides Haeckel’s corals and the like, the outcome of the travels of Semon and Kükenthal in Australia and New Guinea—lands whose very outline could barely be traced in the mist when Schiller was a professor at Jena. At the entrance there are two stuffed orangs, our distant cousins. One wall of the lecture-hall is covered with huge charts depicting the genealogical tree of life, as it is drawn up by Haeckel. With what eyes Schiller would have devoured them! Yet classic traits are not wanting. From Haeckel’s fine study in the Institute the eye falls on the Hausberg, “the mountain-top from which the red rays stream.” It is the room in which the deep-sea radiolaria of the Challenger Expedition were studied, a zoological campaign in depths of the ocean that were stranger to Schiller’s days than the surface of the moon is to us. Behind this Goethe-Schiller seat at the observatory there is a natural depression full of willows that reminds us of the time when all was country here. But just beyond it is a modern street—“Ernst Haeckel Street,” as it was named, in honour of him, on the occasion of his sixtieth birthday. Close to it is the villa where he has lived for many years with his devoted family, full of wonderful reminiscences (oil-paintings and water-colours from his own hand) of his many travels. In Schiller’s day a voyage to Ceylon would have been a life’s work. To-day it is an episode in an infinitely richer and broader life. On the stone seat now we see the proud and handsome figure of the man himself, recalling pleasantly the masters who have stood here before him, the wide hat covering the white hair that is belied by the rosy cheeks; a straight and strong figure, yet revealing in the finer lines of the face the sensitive, æsthetic temper that does not look on scientific investigation as a brutal power of the dissecting knife, but remembers he is the heir of Goethe, even in the Zoological Institute yonder. Over my mind came the feeling of a strange rebirth of things. I felt that life is an eternally new and mystic resurrection, immeasurably more wonderful and profound than all the crude ideas of resurrection that have yet prevailed. A mind such as we love to picture to ourselves in our ideal of the future historian must seek the eternal and constant features in all change, even in two epochs that are so distinct and in the men who have lived in them. It is our incorrigible schoolmaster disposition that divides things. In the real world there must be one straight line of development. To-day the highest is sought in the melody of immortal verse: to-morrow a Zoological Institute rises on the spot where the poet had stood.

It is said that the boy did not come under the influence of Goethe without some difficulty. His mother did not like Goethe; she preferred Schiller. Goethe was too great for every true soul to follow him in his arduous path. Weimar itself had more than once been disposed to desert him. How much more the general public in its conventional fetters! How many fell away from him when he published the Roman Elegies, and again when he brought out the Elective Affinities. In Haeckel’s youth people remembered Börne’s narrow and hostile strictures. Goethe began to penetrate into the German family as a classic in spite of the general feeling. But the German family was still far below him. He had gradually to lift it up from its Philistine level. At times it rebelled against him, as every stubborn level does against a peak. It was his aunt Bertha that first put Goethe’s works into the boy’s hands. He received them as a delightful piece of moral contraband.

Gottfried Keller has finely described, about the same period, in his Green Henry, the effect of such a revelation on a sensitive young man. A bookseller brings to the house the whole of Goethe’s works, fifty small volumes with red covers and gilded titles. The young Swiss Heinrich, Keller’s picture of himself, reads the volumes unceasingly for thirty days, when they are taken away because his mother cannot pay for them. But the thirty days have been a dream to the boy. He seems to see new and more brilliant stars in the heavens as he looks up. When the books are removed, it is as if a choir of bright angels have left the room. “I went out into the open air. The old town on the hill, the rocks and woods and river and sea and the lines of the mountains lay in the gentle light of the March sun, and as my eye fell on them I felt a pure and lasting joy that I had never known before. It was a generous love of all that lives, a love that respects the right and realises the import of each thing, and feels the connectedness and depth of the world. This love is higher than the artificial affection of the individual with selfish aim that ever leads to pettiness and caprice; it is higher even than the enjoyment and detachment that come of special and romantic affections; it alone can give us an unchanging and lasting glow. Everything now came before me in new and beautiful and remarkable forms. I began to see and to love, not only the outer form, but the inner content, the nature, and the history of things.” The poet compresses his experience into one episode. In real life it comes slowly, step by step. In fine, a third element was born in the young botanist and lover of beauty—Goethe’s view of life behind all else: that which Goethe himself called “objective.” The mystic might call it a return to God: but it was Goethe’s God.

Three other books influenced Haeckel in his school-days, besides the works of Goethe. The first was Humboldt’s Aspects of Nature. This is another work that has had an effect on all the sensitive spirits of the nineteenth century. It is most unjustly depreciated by the young, blasé generation of our time, which dislikes the older style. In the first two volumes of the Cosmos we see the play of a great mind wherever we look for it.

Then came Darwin’s Naturalist’s Voyage round the World. The ardent youth had as yet on suspicion what the name would one day mean to him. Darwin was then regarded as a completed work on which final judgment had been rendered. He was appreciated as a traveller, a student of the geology of South America, and especially as the gifted investigator of the wonderful coral reefs of the Indian Ocean. His name stood thus in all the manuals, close even to that of Humboldt. Probably the young reader thought he had died long before. At all events, no one had a presentiment that this quiet naturalist and student of corals was about to light a torch that would flame over the world. The chief advantage that Haeckel drew from the two works was an ardent desire to see the tropics, with their virgin forests and blue coral seas. It has come to so many after reading these works, and persisted in their lives as the vivid image of a dream, like that which drove Goethe to Italy—the dream of a home of the soul that must one day be sought.

The third book was Schleiden’s The Plant and its Life. Matthias Jacob Schleiden was then in the best of his power, and had an influence that amounted to fascination on many of the younger men. Behind him lay a terrible struggle. He had begun his career as a lawyer, and had been so unfortunate that he even attempted his life. With his interest in botany a new life began, and he worked with the energy of one raised from the dead. He was certainly an original thinker. His name is known to us to-day especially as the founder of the cell-theory. This is the greatest distinction that he has earned. But at that time he had a much more general importance as a leader in the struggle to introduce a certain method of scientific research. A somewhat obscure epoch was coming to a close, a more or less superficial natural philosophy having sought to replace sound investigation. The struggle had ended with the decisive victory of the simple discovery of facts. There was everywhere a vague feeling that the progress of science was best secured by a bald enumeration and registration of bones, of the joints in the limbs of insects, or of pollen-filaments, rather than by the romantic and spirited leaps of natural philosophy over all the real problems into the heavens above. The question now arose whether this narrow method really exhausted the nature of things; whether scientific specialism, with its laurels of victory, would not prove in the end an equally dangerous enemy. What was “better” for the time being might be very far from really “good.” It was here that Schleiden stepped in. He fought against the prevailing specialism, at first in his own particular province of botany. He did not, indeed, take up the cause of the exploded pyrotechnics of the older natural philosophy, but pleaded for more general critical-philosophical methods. These must be preserved in any circumstances. The great botanist, he said, is not the man who can determine ten thousand species of plants according to the received models, but the man of clear logic and wide deductions from his lore. Botany must be conceived as a distinct branch of general thought; otherwise it is worthless, and its herbarium may rot unnoticed in the corner and its discoveries be the outcome of blind hazard. Schleiden himself had no perception of the great idea that Darwin was to bring into his province afterwards—the idea of the variability of species and of evolution, which brought to a critical stage the question whether the botanist was to be merely a subordinate museum-secretary or a creative thinker, a prophet of nature to whom plants would be part of a general philosophy, a part of God in the ideal sense of evolution. Yet Schleiden’s simple warning cry made a deep impression on many of the young men especially. There was a note of aspiration in it, an assurance that they were waiting for a sun that must rise somewhere. He was a master of language. There was the stuff of the poet in him. His works strayed out far beyond the range of his own province. Haeckel himself did the same work in later years. It is no wonder that Schleiden had a magical influence over him. In this case, indeed, it seemed as if the attraction was to determine his own career.

Schleiden taught botany at Jena University. Haeckel was still in the higher forms of his school at Merseburg, and remained there when his father resigned his position in the State service, and eventually removed to Berlin. At this time the ardent botanist decided to adopt the science of plants as his life-study when his final examination was over. Schleiden would teach him how to combine philosophy with botany. Then he would try to roam over the world as a practical botanist and visit the far-off zones where Mother Earth poured out her cornucopia of forms so generously.

While still in the higher form at school he made a preliminary visit to Jena. Everything seemed so pleasant and charming. He made the journey on foot. These long walks have always been his pride—to start out like a travelling scholar, with hardly anything in his pocket, to live on bread and water, and sleep in the hay at night; but to enjoy to the full all the incomparable delights that the great magician, nature, provides for the faithful novice—scenery, beautiful orchids, thoughts of God, Goethe, and the world. It was in 1849 that he visited Jena. He has described it himself: “After I had reverently admired the Goethe-room in the castle of Dornburg, I wandered, on a hot July day, over the shady meadows to Jena, singing lustily with my gay comrades. As I entered the venerable old market-place I found a troop of lively students in front of the Burgkeller, with coloured caps and long pipes, singing, and drinking the famous Lichtenhain beer from wooden tankards. It made a great impression on me, and as I took a tankard with them I made up my mind that I would some day be one of them.”

CHAPTER II
AT THE UNIVERSITY

It was botany itself that thwarted all these designs. The examination had passed off happily. Rooms were taken at Jena, at the Easter of 1852, for the advanced study under Schleiden. Then the indefatigable collector had an adventure on a cold March day. He spent hours in the wet meadows by the river Saale, searching for a rare plant, the squill (Scilla bifolia). He met with the fate of the angler in the story, who fell into the water in his haste to secure his big pike. He landed the fish, but not himself. The plant was found, but Haeckel’s zeal was punished with a severe rheumatism. He had to go home to his parents at Berlin to be tended. At Berlin he begins his studies, and the event to some extent decides his career. It would now be many years before he would see Jena again; and through his efforts it would become one of the leading schools, not of botany, but of zoology—a school of philosophical zoology, however, in the sense of Schleiden.

Berlin had secured a botanist of the first rank a year before, Alexander Braun. He, too, was a thoughtful botanist, who would in his way agree very well with Schleiden. He was convinced that botany did not wholly consist in the determination of new plant forms and the almost fruitless effort to set up a system on which all particular diagnoses would be rigidly played as on a piano. He believed that there must be a more profound conception of it, which would take “form,” as such, as one of its problems, and would aim, not at the formation of as large a collection as possible, but at the construction of a science for which Goethe had long ago found a name—morphology, or the science of forms. It happened that Braun was a friendly visitor at the house of Haeckel’s parents at Berlin. The now convalescent freshman became devoted to him, body and soul; they became close friends, not merely master and pupil. Berlin at that time afforded many an opportunity for practical botanising. Rare marsh-plants then flourished in the bed of the Spree, which has since been cleared. The Botanical Garden was full of good things. Haeckel used to tell with pride, long afterwards, with what readiness he flung himself into the work, practical as well as theoretical, on these excursions with Professor Braun. “On one of our botanical expeditions we wanted to get a floating chara from a pond. Braun took off his boots in his usual way in order to wade to the spot. But I was before him. I quickly undressed, forgot my naughty rheumatism, and swam to the spot, to bring him a quantity of the plant he wanted. That was my first piece of heroism, perhaps my greatest.”

But in all this pleasant botanising there was no serious outlook on his future profession. Haeckel’s father, with his official way of looking at things, could not reconcile himself to scientific research as an avocation. It is an old belief that the way to all preoccupation with the science of living things lies through medicine. One may question that to-day. It was the rock on which Darwin nearly came to grief. A man may be a very gifted botanist, yet be quite unfitted for the medical profession. One must have a real vocation to become a physician, more than for any other calling, or else it is a hopeless blunder. The talents are divided in much the same way as between the historian and the soldier. It is true that the two may be united, but it is equally true that very good historians have made very poor soldiers. What the medical man learns in his studies is, of course, always valuable. But it offers no test of personal talent for scientific research, nor should it be supposed that a capacity of this kind would be able, by mere formal study, to acquire the true qualities of a physician. We must learn to appreciate the physician’s calling too much ever to look on it as an incidental occupation. It always reminds me of the amiable notion of the Philistine, that a man with a turn for poetry must first take up some solid profession, and then, once he is “in the saddle,” pour out verses in his leisure hours. Poetry can never be a mistress: it demands marriage or nothing. Otherwise—well, we have instances enough.

Haeckel himself afterwards said that he only acceded to his father’s wish, that he should study medicine, with a botanical mental reservation. He thought of going through the discipline conscientiously until he became a physician, and then secure a place as ship’s doctor, and travel over the world and see the tropics. Things turned out very differently. He never became a medical man such as his father had wished, but he passed over the profession into zoology. Botany remained the lost and never-forgotten love of his youth. When we look back on his whole career we can see that he was, on the whole, fortunate. Zoology afforded a richer, more abundant, and more varied material at that time. It proved to be more “philosophical.” He went after his father’s asses and found a kingdom. But to him personally it seemed to be an unmistakable renunciation—the first in an active career that was to see many resignations.

“He goes farthest who does not know where he is going.”

Haeckel once applied this motto to himself and his star, in a humorous after-dinner speech. With this kind of safe predestination he reached Würtzburg in the autumn of 1852 as a medical student. Medicine had in those days received an entirely new theoretical basis from Würtzburg—a basis that was calculated to attract a young inquirer, who brought much more of the general Faust-spirit to his work than aspiration to the profession and the doctor’s cap, or the practical side.

Let us recall for a moment how medicine had gradually reached the position of an independent science. Medicine was the outcome of a remote mythical epoch. It was content with the effect of certain venerable traditional medicaments on the living body, but knew little or nothing of the inner structure of the body on which it tried its drugs. The dissection and examination of even a corpse was regarded as a deadly sin, and was visited with secular punishment. Scientific medicine did not exist until this prohibition was removed; its first and most necessary foundation was anatomy, the science of the bodily structure and its organs. The art of “cutting up” bodies had seemed too revolting. Moreover, no sooner had the science of anatomy been founded than the range of the human eye itself was considerably enlarged. The microscope was invented. A new world came to light in the dissection of the body. Beyond their external appearance it revealed the internal composition of the various organs. The eye sees a shred of skin, a piece of intestine, or a section of the liver. The microscope fastens on a tiny particle of this portion of the body, and reveals in it a deeper layer of unsuspected structures. It is well known in the history of microscopic discovery that the more powerful lenses and the improved methods of research were only gradually introduced, and enabled students to found a new and much profounder anatomy. As soon as this science appeared it was given the special name of “histology,” or the science of the tissues (hista). Its particular achievement is the discovery that in man, the animal, and the plant, all the parts of the body prove, when sufficiently magnified, to be composed of small living elements, which are known as cells. The discovery of the cell was made in the latter part of the third decade of the nineteenth century. These cells join together in homogeneous groups in order to accomplish one or other function in the body, and thus form its “tissues.” Their intricate structure is unravelled by the histologist, microscope in hand. It is evident that in this way a new basis was provided for anatomy, and therefore also for medicine. In the fifties Würtzburg was the leading school of histology, or the science of these tissues composed of cells. Albert Kölliker, professor of anatomy there since 1847, published his splendid Manual of Histology at the very time when Haeckel was studying under him. Franz Leydig, a tutor there since 1849, was working in the same direction. The third member of the group, made professor in 1849, was Rudolf Virchow, a young teacher then in his best years. It was Virchow who did most to bring practical medicine into line with histology. As the vital processes in the human body seemed to him, with his strict histological outlook, to be traced back always to the tissue-building cells, he concluded that disease also, or the pathological condition of the body, and therefore the proper field of the medical man, was a process in these cells. Man seemed to him to be a “cell-state”: the tissues were the various active social strata in this state: and disease was, in its ultimate source, a conflict in the state between the citizens, the tissue-forming cells, that normally divide the work amongst them for the common good. Pathology must be cellular pathology. The science was already being taught by Virchow at Würtzburg, and the dry bones of it were covered with flesh for his hearers. But his ideas were not published until a few years afterwards (1858).

In the first three terms Haeckel studied chiefly under Kölliker and Leydig. They taught him animal and human embryology, as it was then conceived. Embryology was the science of the development of the individual animal or man, the description of the series of changes that the chick passes through in the egg or the human embryo in the womb. This science, also, had been profoundly affected by the invention of the microscope. Firstly, the spermatozoa, the active, microscopically small particles in the animal and human sperm, had been discovered. Then, in the twenties, Karl Ernst von Baer had discovered the human ovum. The relation of these things to the cell-theory was clear. It was indubitable that each of these male spermatozoa and each female ovum was a cell. They melted together and were blended into a new cell in the act of procreation, and from this, by a process of repeated cleavage of cells, the new individual was developed with all his millions of cells and all the elaborate tissues that these cells united to form. A whole world of marvellous features came to light, but the key to the unriddling of them was still wanting.

However, the Würtzburg school was at least agreed as to method, which was the main thing; its leaders were determined to press on to the solution of these problems on purely scientific lines. Everything was to be brought into a logical relation of cause and effect, and there was to be no intrusion of the supernatural, no mysticism. Natural laws must be traced in the life of the cells and in the history of the ovum and the embryo. The cells were to be regarded in the same way as the astronomer regards his myriads of glittering bodies. In this way the science of histology had been founded, and embryology had assumed a scientific character in the hands of Von Baer. The microscope kept the attention of students to facts, and did not suffer them to lose themselves in the clouds. Thus a foundation-stone was laid in Haeckel’s thoughts which he would never discard.

In the later years of the Darwinian controversy he was destined to come into sharp conflict with both Virchow and Kölliker. Each of them came to look on him as the sober hen does on the naughty chick it has brought into the world, that madly tries to swim on the treacherous waters of Darwinism. But forty years afterwards—after many a knife-edged word had been thrown in the struggle—the aged Kölliker was one of those who entered their names in the list of men of science who erected a bust in the Zoological Institute at Jena in honour of Haeckel’s sixtieth birthday.

However, it was a different, an apparently trivial, yet, as it turned out, most momentous interest that quickened him during these University years.

The impulse to microscopic research, that had led to the foundation of histology and embryology, had brought about a third great advance which had an important bearing on zoology. When we stroll along the beautiful shore of the Mediterranean at Naples to-day, with eyes bent on the blue surface from which Capri rises like a siren, and on the cloud-capped Vesuvius with its violet streaks of lava cutting across the green country, we notice in the foreground of the picture a stout building, with very large windows, planted with the boldness of a parvenu amongst the foliage. It is the “Zoological Station,” built by Dohrn, a German zoologist, at the beginning of the seventies. Anton Dohrn was one of Haeckel’s first pupils, and was personally initiated by him into the study of marine life, at Heligoland in 1865. Zoologists who work in the station to-day find it very comfortable. Little steamers with dipping apparatus bring the inhabitants of the bay to them. There is a large aquarium at hand. You sit down to your microscope, and work. The material is “fresh to hand” every day. There are now many of these stations at well-exposed spots on the coast in various countries—sea-observatories, as it were, in which the student examines his marine objects much as the astronomer observes his planets and comets and double stars at night. To-day, when a young man is taking up zoology, and he is asked what university he is going to, he may say that he is going down to the coast, to Naples, to do practical work. When the long vacation comes, swarms of professors go from the inland towns to one or other seaside place, as far as the purse will take them. All this is a new thing under the sun. The zoologist of the olden days sat in his study at home. He caught and studied whatever was found in his own district. The rest came by post—skins, skeletons, amphibians and fishes in spirit, dried insects, hard shells of crustacea, mussels and snails of all sorts; but only the shells always, the hard, dry parts of star-fishes, sea-urchins, corals, &c. Animals of the rarest character were thrown away because they could not very well be preserved in spirit and sent from the North Sea or the Mediterranean to Professor Dry-as-dust. In this state of things the advance in microscopic work brought no advantage. But at last it dawned on students that the sea is the cradle of the animal world. Whole stems of animals flourished there, and there only. Every wave was full of innumerable microscopic creatures, of the most instructive forms. Amongst them were found the young embryonic forms of familiar animals. At last the cry, “To the sea,” was raised. The older professor of zoology had suffered from a kind of hydrophobia. It was not possible to teach very much at Berlin about the anatomy, histology, and embryology of the sea-urchin from a few dried flinty shells. At Würtzburg, animals were subtly discussed by men who had never made a journey to see them, while they were trampled under foot every day by the visitors bathing in Heligoland. They must move. It was not necessary to go round the world: a holiday journey to the North Sea or the Mediterranean would suffice. Every cultured man had always considered that he must make at least one pilgrimage to classic lands before his education was complete. It was only a question of changing material. They were not to confine themselves to examining ruined temples and aqueducts, but to take their microscopes down to the coast, draw a bucketful of sea-water, and examine its living contents—the living medusa and sea-urchin, and the living world of the swarming infusoria. But it was like the rending of the great curtain of the temple. Zoology seemed to expand ten-fold, a hundred-fold, in a moment. A room in an obscure inn by the sea, a microscope, and a couple of glasses of salt-water with sediment every morning—and the finest studies at Paris and London were as ploughed land, without a single blade, in face of this revelation. It was a Noah’s ark in the space of a pinch of snuff.

One day the young medical student heard, in the middle of his histology and zoology, that Kölliker had come back from Messina. He had been studying lower marine life there. In 1853, two young men were together in the Gutenberg forest near Würtzburg. One of them, Karl Gegenbaur, had been abroad with Kölliker. With his impressions still fresh, he tells Haeckel about his zoological adventures in the land of the Cyclops.

Gegenbaur, eight years older than Haeckel, was by birth and education a typical Würtzburger. He, too, had studied medicine, and had practised at the hospital. But he had already advanced beyond that. His stay at Messina had been devoted entirely to zoological purposes. A year later he would be teaching anatomy at Würtzburg, and a year later still he would be called to Jena. From that time he began to be known as a master of comparative anatomy—especially after 1859, when his Elements of the science was published, a classic in its way that still exercises some influence.

There is nothing romantic in his career, nor could we seek any element of the kind in a man of Gegenbaur’s character. But his young and undecided companion seemed to catch sight of a new ideal as he spoke. He would complete his medical studies, and then shake himself free of surgery and hospital. He would take his microscope down South, where the snowy summit of Etna towered above the orange-trees, and study the beautiful marine animals by the azure sea and the white houses, in the orange-laden air, and drink in ideas at the magic fount of these wonderful animal forms, and live out the lusty, golden years of youth on the finest coast in Europe. From that moment Haeckel felt a restless inspiration. He had no idea what it was that he was going to investigate at Messina; and he certainly did not know when and how he was to get there. But he continued his medical studies with a vague hope that it was only preliminary work; that some day he would do what his friend Gegenbaur had done.

They were very good friends, these two. They were drawn together by the strong magnetism of two true natures that understood each other to the golden core, though in other respects they were as different as possible. Gegenbaur was no enthusiast. His ideal was “to keep cool to the very heart.” But he was at one with Haeckel in a feeling for a broad outlook in scientific research. He never shrank from large connections or vast deductions, as long as they were led up to by a sober and patient logic. This logical character he afterwards recognised in Darwin’s idea of evolution, and so the friends once more found themselves in agreement, and for a long time they were a pair of real Darwinian Dioscuri. This feeling for moderation and at the same time for far-reaching logic was combined in Gegenbaur with a certain steady and unerring independence of character. He made little noise, but he never swerved from his aim. What he accomplished with all these qualities, in many other provinces besides Darwinism, cannot be told here. It may be read in the history of zoology. He had, as far as such a thing was possible, a restful influence of the most useful character on Haeckel. If we imagine what Darwinism would have become in the nineteenth century in the hands of such men as Gegenbaur, without Haeckel, we can appreciate the difference in temperament between the two men. With Gegenbaur evolution was always a splendid new technical instrument that no layman must touch for fear of spoiling it. With Haeckel it became a devouring wave, that will one day, perhaps, give its name to the century. In other natures these differences might have led to open conflict. But Haeckel and Gegenbaur show us that, like so many of our supposed “differences,” they can at least live together in perfect accord in the freshest years of life, each bearing fruit in its kind.

When we find Haeckel intimate in this way with Gegenbaur, his senior by eight years, we realise how close he was at that time to the whole of the Würtzburg circle. The two generations were not yet sharply divided, as they subsequently were. Most of them fought either with or against him at a later date, but they belonged, at all events, to the same stratum. But the split between the two generations was felt when one pronounced the name of Johannes Müller, of Berlin—the physiologist (not the historian).

All who then taught histology, embryology, comparative anatomy, or cellular pathology at Würtzburg had sat at his feet, either spiritually or in person. Johannes Müller, born at the beginning of the century, was appointed Professor of Anatomy and Physiology at Berlin the year before Haeckel was born. That indicates the distance between them. It was in Müller’s incredibly primitive laboratory that, as Haeckel tells, the theory of the animal-cell was established by his assistant, Theodor Schwann, after Schleiden had proved the vegetal cell. Müller himself had founded histology in his own way. He was the real parent of the idea that the zoologist ought to go and work by the sea. We have a model of this kind of work and at the same time a superb work for embryological matters in Müller’s epoch-making Studies of the Larvæ and Metamorphoses of the Echinoderms. He had brought comparative anatomy beyond the stage of Cuvier, to a point where Gegenbaur could begin. From his school came Rudolf Virchow, who applied the cell-theory to medicine, and Emil du Bois-Reymond, who opened out a new path in physiology by his studies of animal electricity. Müller had done pioneer work with remarkable vigour in all the various branches of research, diverging afterwards to an enormous extent, that pursue these methods. The many-headed (young and half-young) generation, in which Haeckel was growing, saw the whole previous generation embodied in the single name of Müller. He seemed to be a kind of scientific Winkelried, except that the fifty spears he bore on his breast were so many lines of progress emanating from him alone.

Johannes Müller had the great and splendid gift of never lying on the shoulders of his pupils with an Alpine weight of authority. It was a secret of his personality that we admire but can hardly express in words to-day. Everybody learned from him what a great individuality is. He exerted a kind of moral suggestion in teaching men to be free, great, enlightened, and true. His pupils have worked at the development of his ideas with absolute freedom. No part of them was to be regarded as sacred, and, as a matter of fact, in the chief questions no part has remained.

One approaches the inner life of a man like Müller with a certain timidity, and asks how he became what he was. There can be no question that the fundamental trait of his character was a peculiarly deep religious feeling. At heart he was a mystic. The whole magic of his personal influence sprang from these depths. By profession he was a physiologist, an exact scientist. Never did he swerve a hair’s breadth from the iron laws of research. But beneath it all was a suppressed glow of fervour. Every one who understood him, every one who was a true pupil of his, learned it by a kind of hypnotism. Externally he was all for laborious investigation, whether in dissecting a star-fish for you or classifying fishes—though he would have a full sense of your ardent longing for an inner trust in life and a philosophy of life. Both elements might change considerably in the pupil: the method of investigation without—the ideal of the comprehensive vision within. But what never left any man who had followed Müller was the warning cry that these things, within and without, should go together; that, in the larger sense, it is not possible to count the joints in the stalk of an encrinite without feeling a thrill in the deepest depth of the mind and the heart.

It is so common a spectacle in history for disciples to condemn their masters with cold smiles that we forget how pitiful it is. No pupil of Johannes Müller has ever felt that he had done with him, and might quit him with ingratitude. He had pupils, it is true, who did not lack belief in themselves, and who became famous enough to give them a sense of power; men who have eventually come to conclusions diametrically opposed to those that Müller had taught them. Yet they respect him. Living witnesses still tell of the glance that bored into you, and could not be evaded. But there must have been a greater power in the man than this piercing glance. It was a glance that survived the grave, and laid on one a duty; a glance that shot up in the darkness of memory if the duty was not fulfilled—the duty of going to the foundation of things. Whether you are examining the larva of an echinoderm or the light of a distant star, God is there. Whether you explain your echinoderm-larva in this way or that; whether you believe your star to be a sun or a burnt-out cinder; whether you conceive God in this way or another—you shall feel that the bridge is there in absolutely everything. Every glance into the microscope is a service of God. It was Goethe’s deepest sun that threw a great, radiant spark out of this curious, dark, angular, unintelligible jewel.

Such a man was bound to be more than Kölliker, Virchow, and Gegenbaur to Haeckel. Müller was still teaching at Berlin, and Haeckel’s best star brought him to sit in reality at the feet of the great teacher, who could so well speak soul to soul to him.

At the Easter of 1854 Haeckel returned from Würtzburg to Berlin. He was now twenty years old, and it was at this juncture that, to use his own phrase, the vast impression of Müller fell on him. A portrait of Müller still hangs over the desk in his study in the Zoological Institute at Jena. “If I ever become tired at my work,” he says, “I have only to look at it to get new strength.” The influence of the much older man, who, however, died at a far earlier age than Haeckel will do, only lasted for a short time. But Haeckel has preserved a memory of him that is only eclipsed by the memory of one other man—Darwin. Müller did not live to read Darwin’s decisive work, so that these two great ideals of Haeckel’s never crossed each other, either for good or evil. He himself felt that there was a pure evolution from one to the other in his mind.

In the summer of 1854 he studied comparative anatomy under Müller, for which Kölliker had sufficiently prepared him. He has recorded his first impressions. “I soon got to know him personally, but I had so great a respect for him that I did not venture to approach him more closely. He gave me permission to work in the museum. I shall never forget the hours I spent there, drawing skulls, while he walked up and down, especially on Sunday afternoons. Often when he went past me I wanted to ask him something. I went up the step with beating heart and took hold of the bell, but returned without venturing to say anything.” Müller took some notice of the zealous young student. When the long vacation came round in August, and the master, following the new custom, packed up his bundle in order to spend two months on practical work by the sea, he allowed Haeckel to go with him. Müller’s son and the later Professor La Valette joined the party. They went to Heligoland. Müller taught his pupils his simple method of studying the living subject. There was no witchcraft in it, but it had had to be invented by some one. They put out to sea in a small boat. A little net of linen or fine gauze, with a wide opening and short body, was fastened on a pole. The mouth of the net was thrust directly under the surface or a little deeper, vertically to the surface, and the boat was slowly rowed forward. The contents of the filtered sea-water remained in the meshes of the net, and were from time to time emptied into a glass containing sea-water. “I shall never,” says Haeckel, “forget the astonishment with which I gazed for the first time on the swarm of transparent marine animals that Müller emptied out of his fine net into the glass vessel; the beautiful medley of graceful medusæ and iridescent ctenophores, arrow-like sagittæ and serpent-shaped tomopteris, the masses of copepods and schizopods, and the marine larvæ of worms and echinoderms.” Müller called these very fine and generally transparent creatures, of whose existence no one hitherto had had any idea, “pelagic sweepings” (from pelagos, the sea). More recently the word “plancton” (swimming matter) has been substituted for his phrase. As we now send whole expeditions over the seas to study “plancton,” the word has found its way into ordinary literature. The regular anglers who were then in Heligoland must have looked on this subtle work with a butterfly net as a sort of pleasant joke born from the professional brain. The young student must have made an impression on them with his vigour, though he had not yet turned himself into a marine mammal, living half in the water for days together. They called him a “sea-devil.” What pleased the master most in him was the talent he already showed of quickly sketching the tiny, perishable creature from the surface of the sea while it was fresh. Haeckel had been passionately fond of drawing from his early years. Now the old bent agreed with the new zeal for zoology. “You will be able to do a great deal,” Müller said to him. “And when once you are fairly interested in this fairy-land of the sea, you will find it difficult to get away from it.” The dream of Messina, that Gegenbaur had conjured up, seemed to draw nearer.

Fishing in Heligoland in 1865.
Anton Dohrn (Naples). Richard Greeff (Marburg). Ernst Haeckel (Jena).
Max Salverda (Utrecht). Pietro Marchi (Florence).

These lively days at Heligoland provided Haeckel with the material for his first little zoological essay. It dealt with the development of the ova of certain fishes (On the Ova of the Scomberesoces, published in Müller’s Archiv for 1855). Müller lent him ova from the Berlin collection to complete his study. It is the same volume of the Archiv in which, in Reichert’s introduction, the great controversy breaks out over Virchow’s pregnant assertion that each human being is a state composed of millions of individual cells.

Haeckel remained with Müller at Berlin for the whole winter, and was drawn more and more into the province of comparative anatomy, or, to speak more correctly, zoology. The official Professor of Zoology at Berlin at the time was really the aged Lichtenstein, who had occupied the chair since 1811. Haeckel has humorously described himself in later years as self-taught in his own subject, saying that he had attended many most excellent colleges, but never visited an official school of zoology. The only opportunity to do so at the time was under Lichtenstein, but that professor bored him so much that he could not attend his lectures. Lichtenstein was a venerable representative of the old type of zoologist; his ideal was to give a careful external description of the species on the strength of specimens chosen from a well-stocked museum. A whole world lay between these surviving followers of Linné and the splendid school of Johannes Müller.

However that may be, the fact was that under these alluring attractions Haeckel’s studies were drifting from the medical profession to an “impecunious art.” But as medical work had been chosen, if only as a temporary occupation, Haeckel had to tear himself away from the great magnet, at the Easter of 1855, by removing to a different place. He chose, as the least intolerable compromise, to return to Würtzburg. At all events we find him spending three terms there. I have already said that Rudolf Virchow was one of the distinguished Würtzburgers at the time who sought most keenly the solution of the new problems of biology on the medical side. Hence Virchow had to help him to find the bridge between the work he really loved and the work he was obliged to do. As a fact, Virchow directed the whole of his studies on this side in the three terms.

Virchow was not so fascinating as Johannes Müller, even in his best years. But it was something to be initiated into medical science by such a man. A later generation has, unfortunately, grown accustomed to see mental antipodes in Virchow and Haeckel. In 1877 they had a controversy with regard to the freedom of science that echoed through the whole world of thought. Yet seventeen years afterwards Haeckel himself (who was first attacked by Virchow), looking back on the days he spent at Würtzburg, had nothing but grateful recognition to say of Virchow. “I learned,” he says in 1894, “in the three terms I spent under Virchow the art of the finest analytic observation and the most rigorous control of what I observed. I was his assistant for some time, and my notes were especially praised by him. But what I chiefly admired in him at Würtzburg was his wide outlook, the breadth and philosophic character of his scientific ideas.”

The theory that Virchow put before his pupils was pure Monism, or a unified conception of the world without any distinction of physical and metaphysical. Life was defined, not as a mystic eccentricity in an orderly nature, but plainly as a higher form of the great cosmic mechanism. Man, the object of medical science, was said to be merely a higher vertebrate, subject to the same laws as the rest.

We can see very well that this was quite natural. If there was any man likely to put forward such views it was Virchow. He had passed through Müller’s school, but was now one of the younger group who, even during Müller’s life, were gradually adopting certain very profound views on life and man, without any particular resistance on the master’s part. The chief characteristic of nearly the whole of this group was the lack of the volcanic stratum below of deep and personal religious feeling; in Müller this had been throughout life an enchained Titan among the rocks of his logical sense of realities, yet it had given a gentle glow and movement to the floor of his mind. Rudolf Virchow was the coolest, boldest, and clearest-minded of the group. He went to the opposite extreme. If Müller was standing on a volcano, which he only repressed by the giant force of his will—a nature that was above all master of itself—Virchow, on the contrary, was standing on a glacier, and he had never taken the trouble to conceal it. I should not venture to count him amongst the instinctively Monistic minds, in the sense of Goethe, to whom the unity of God and nature, the inorganic and the organic, the animal and the man, comes as an ardent and irresistible feeling. But it would have been strange if, in those years and in the middle of the whole scientific current of his time, his own organ, his icy logic, had not led him to the same conclusion; that it is a simpler method of research to believe in natural law alone, to regard the living merely as a complex play of the same forces that we have in physics and chemistry, and to consider man, with the bodily frame of an ape-like mammal, to be really such an animal. I believe, indeed, that Virchow never abandoned this simple solution in his own mind at any part of his career. The controversy he afterwards engaged in ran on different lines. It seems to me that at an early stage of his development he became convinced that there must be limits to scientific inquiry, not on logical, but on diplomatic grounds; because it is not an absolute agency, but only a relatively small force amongst many more powerful institutions, the Church, the State, and so on. Hence it would have to respect limitations that were not drawn from its own nature; in given cases it would have to keep silent in order not to jeopardise its existence as a whole. It is my firm belief that this diplomatic attitude as such would lead to the destruction of all pursuit of the truth. It carefully excludes the possibility of any further martyrdoms, but at the cost of science’s own power to illumine the world. In my opinion the free investigation of the truth is an absolute right. Churches, States, social orders, moral precepts, and all that is connected with them, have to adjust themselves to this investigation, and not the reverse.

However, the point is that under Virchow—more particularly under Virchow, in fact—Haeckel would be educated into the general attitude with regard to God, nature, life, and man, to which he has since devoted his whole energy. In spite of Goethe—and who would be likely to take Goethe as his guide in his twenty-first year?—the ardent young student was as yet by no means firmly seated in the saddle. He grubbed, and sought, and rejected. In his Riddle of the Universe he tells us that he “defended the Christian belief in his twenty-first year in lively discussions” with his free-thinking comrades, ... “although the study of human anatomy and physiology, and the comparison of man’s frame with that of the other animals, had already greatly enfeebled my faith. I did not entirely abandon it, after bitter struggles, until my medical studies were completed, and I began to practise. I then came to understand Faust’s saying, ‘The whole sorrow of humanity oppresses me.’ I found no more of the infinite benevolence of a loving father in the hard school of life than I could see of ‘wise providence’ in the struggle for existence.”

When the three terms of medical training were over, he received another impulse to his own particular interest in science. Kölliker invited him in August, 1856, to spend the two months’ holiday with him on the Riviera. It was the first Mediterranean school of zoology, though as yet only a kind of “payment on account.” On the journey he made the acquaintance of the zoological museum at Turin and its well-travelled director, Filippo de Filippi, and he saw the grandeur of the Maritime Alps on the Col di Tenda. The master, Kölliker, Heinrich Müller, Karl Kupffer (afterwards professor at Munich), and he established themselves at Nice, and fished for all sorts of creatures with the Müller-net at Villefranche. Fortunately, Müller himself happened to be visiting the Riviera at the same time, and they received a direct stimulus from him. The first result of this journey in the summer and autumn was that Haeckel secured his degree with a zoological-anatomical work, instead of with a strictly medical treatise. As he had done from Heligoland two years before, he now brought home from the Mediterranean the material for a short technical theme. He again spent the winter at Berlin to put it together. It was an histological study of the tissues of crabs, and therefore lay in the province of the articulates, an animal group, it is curious to note, which he has not entered into more fully in the course of his long and varied work as special investigator. At Nice he made a thorough study of the nerve-tubes of the spiny lobster and other available marine crustacea, and discovered several remarkable new structural features in them. At Berlin he entered upon a minute microscopic study of the common craw-fish. His dissertation for the doctorate embodied the main results of his research. It was entitled De telis quibusdam Astaci fluviatilis, and was printed in March, 1857. It appeared the same year in an enlarged form in Müller’s Archiv, with the title The Tissues of the Craw-fish. On March 7th he received his medical degree, Ehrenberg, the great authority on the infusoria, presiding. In the customary way the young doctor had to announce and defend several theses. One of them is rather amusing in view of later events.

He most vigorously contested the possibility of “spontaneous generation.” The meaning of the phrase is that somewhere or at some time a living thing, animal or plant, has arisen, not in the form of a seed or germ or sprout from a parent living thing, but as a direct development out of dead, inorganic matter. Haeckel had not made a personal study of the subject. What he said in his thesis was merely a faithful repetition of Müller’s opinion. At that time it was believed that science had empirically disproved spontaneous generation. An old popular belief held that fleas and lice were born every day from non-living dirt and dust, but that had been refuted long before. No egg, no animal: every living thing develops from an egg. This had been laid down as a fixed rule. When the microscope revealed an endless number of tiny creatures in every drop of stagnant water, in the air and the dust and the soil, it was a question whether the rule was not wrong. Surely these simplest of all living things, apparently, were born by spontaneous generation? However, the question was believed to have been settled in two ways. Schwann, the co-discoverer of the cell-theory, had made certain experiments which seem to prove directly that even these tiny beings, the infusoria and bacteria, were never formed in a vessel containing water and dead matter, if it had been carefully assured beforehand that the minute living germs of these animals that floated in the air could not penetrate into the vessel. At the same time Ehrenberg and others stoutly denied that the infusoria were the “simplest” organisms, or that they could conceivably be born in that way. They declared that the infusoria were “perfect organisms” in spite of their smallness. The belief that these tiny creatures consisted of “one cell,” and so formed, as it were, the ultimate elements of the plant and animal worlds on the lines of the cell-theory, was seriously menaced, and apparently on the way to be destroyed. Finally, the tapeworm and similar parasites had been declared to evolve by a kind of spontaneous generation from the contents of the intestines. But this also was proved to be untrue. Thus there was ample material for a solid dogma: there was no such thing as spontaneous generation. The dogma, moreover, harmonised with the prevailing belief in a special vital force and a radical distinction between the living and the dead, which was still shared in a subtle form by even a man like Müller. The dogma was formulated. Spontaneous generation was struck out of the scientific vocabulary as unscientific and a popular superstition. The young doctor, duly initiated into these ideas of the time, could not resist the temptation to give his own kick to the fallen theory. Yet how strangely things have changed since then! Two years afterwards Haeckel ceased to believe in a special vital force; he was now absolutely convinced that there were unicellular beings; his whole theory of life seemed to demand spontaneous generation as a postulate, and he even doubted the force of the experiments of Schwann and others. Haeckel himself became the keenest apostle of the theory of spontaneous generation. Whenever it is mentioned to-day, we think of the weight of his name which he has cast in the scale in its favour. So the leaves change even in the forest of science: yesterday green, to-day red and falling, to-morrow green once more. On the same branch as the dogmas we find the correctives growing, that will at length split them open and cast them as empty husks to the ground.

The history of Haeckel’s medical doctorate can be written in a few plain and touching lines. After receiving his degree he was sent by his prudent father, to keep him away from crabs and other monsters of the deep, to Vienna for a term, to do hospital work under Oppolzer, Skoda, Hebra, and Siegmund. All that we find recorded of this term is that his old love of botany revived in earnest. Immense quantities of dwarf Alpine plants were collected. When the traveller passed by the spot twenty-four years afterwards on a quiet autumn Sunday, on his way to take ship at Trieste for the tropical forests and giant trees of Ceylon, the memory of Schneeberg and the Rose-Alp came upon him like a dream. However, the hospital work, together with a short span of cramming in the winter at Berlin, must have had some effect, as he passed the State-examination in medicine. In March, 1858, he was a “practising physician.” He had in his hand the crown of prudent ambition—and he felt like a poor captive. There was one source of consolation—Johannes Müller. While one was near him there was a possibility of more real work. He discussed with him the plan of the study of the development of the gregarinæ (parasitic protozoa), which he wanted to conduct in Müller’s laboratory in the summer of 1858. Then he was stricken, like so many others, with the thunderbolt of the news of Müller’s sudden death, on April 28th of the same year. What must he do now? He began to practise. It is said on his own authority that he fixed the hours of consultation from five to six in the morning! The result was that during a whole year of this philanthropic occupation he had only three patients, not one of whom died under his earnest attention.

“This success was enough for my dear father,” says Haeckel. We can well believe it.

The kindly old man consented to one more year of quite extravagant study, in which all was to come right. It was to be a year of travel, in Italy. He was to devote himself to the study of marine animals, not merely for pleasure, but earnestly enough for him to find a basis for his life in the result. This he succeeded in doing. Like the children of fortune, who at the very moment when they cannot see a step before them make a move that the Philistine regards as the safest and last refuge, Haeckel becomes engaged that very year to his cousin, Anna Sethe. After that, in January, 1859, he goes down to the coast. He makes for the blue Mediterranean, which he already knows will prove anything but an “unprofitable sea” for him. He will conjure up treasures of science from its crystal depths with his Müller-net; then on to fortune, position, marriage, and the future. The fates have added a world-wide repute, if they have denied many a comfort.

CHAPTER III
THE RADIOLARIA

In the January of 1859 Haeckel, then in his twenty-fifth year, came to Italy with the determination “to do it thoroughly.” By the autumn the body of the peninsula had been covered down to Naples, Capri, and Ischia. The winter, until April, 1860, was spent at Messina.

There are plenty of very strenuous students, later Privy Councillors as well as archæologists and zoologists, who find a year in Italy a very simple matter. They arrive, make the due round of sights, and then at once disappear into some library or institute, burying themselves like moles in some special work or other, just as they would do at home. The only time you can see them is over their Munich beer in the evening; and if there are a number of them together they smoke their cigars and sing a German student’s song, as they would do at home. These good folk have very different dispositions behind their goggles, but they have never been lit up by the fire of Goethe. They are quite content to write home like the churlish Herder; Italy is pretty enough in Goethe’s writings, but one ought not to go there oneself. The modern scholar of this type may add that the cigars are bad and beer dear. Very different was Haeckel’s verdict. “In Sicily I was nearly thrown out of my line and made a landscape-painter.” The æsthetic man in him was the first to lift up his arms with vigour under this new, free, inspiring sun. His words are no idle phrase. The moment he tried it Haeckel discovered that he had a genius for landscape-painting. Even in regard to this gift we see the truth of what I have already said in other connections; the sternest materialists and scientific revolutionaries of the nineteenth century were men of considerable artistic power. There was the solid Vogt, a painter and poet; Moleschott, the soul-comrade of Hermann Hettner; Strauss, who wrote some poems of great and lasting beauty; Feuerbach, and others. Even Büchner, the boldest and most advanced of them all, has written poetry under a pseudonym.[^[1]] Darwin took only two books with him in the little cabin of his ship, Lyell’s Geology and Paradise Lost. There is a complete gallery of fine water-colours in Haeckel’s house to-day that have been brought from three quarters of the globe. His son Walter has inherited the artistic gift, and become a painter. It might be said that a good landscape-painter would hardly recompense us for the loss of the philosopher and scientist that Haeckel became in the nineteenth century. The simple steel pen, the inspired pencil of the thinker, did more for humanity in his hand than could have been done by the most splendid colour-symphonies of the most inspired landscape-painter. I have often thought this as I looked over, in the evening at Haeckel’s house, the then unpublished treasures of his artistic faculty. A work like his History of Creation has counted for a stratum in the thought of humanity. What are even the masterpieces of a Hildebrandt in comparison with it! Yet there was undoubtedly the note of genius in these drawings; some of them showed more than Hildebrandt’s cleverness (we know to-day that Hildebrandt’s highly coloured pictures did not even approximate to the real natural light of southern scenes) and glow of colour. It seemed to me that here again the man had dreams of a lost love: a dream of the gay, wandering pittore, who asks nothing but a sunset in violet, carmine, and gold, instead of being the sober unriddler of the world’s problems. Since that time the house of Fr. Eugen Köhler, to which we owe the fine new edition of Naumann’s classic work on birds, with its coloured plates, has undertaken to publish Haeckel’s water-colours, as “Travel Pictures,” in a splendid and monumental work.

[1]. Büchner’s brother tells how, when Ludwig furtively brought to him the manuscript of Force and Matter, he at once guessed it was a romance or an epic that so much secret work had been expended on. [Trans.]

During the year in Italy all these gifts were employed together. Italy was exactly the land for Haeckel’s temperament, with its mixture of lofty classic elements and natural beauty and simple, naïve unpretentiousness. For the first time he felt that he was a cosmopolitan student. He had never been a devotee of the student’s beer-feasts. He had no need of alcoholic stimulant. Gegenbaur of Würtzburg, the insatiable smoker, once said to him in joke, “If you would only smoke, we might make something out of you.” It was done, in any case. His personal inclinations were in his favour: an illimitable love of travel, good spirits that rose in proportion to the absurdity of his accommodation, and a simple delight in everything human that enabled him to talk and travel with the humblest as if they were his equals. He spent a night with a young worker in a haystack, and when he was asked what he was, he pointed to his paint-box and brush: “House-painter.” “I thought so when I saw you,” said the youth, and he asked Haeckel to start a workshop together with him. Italy was the ideal land for a visitor of that type. There was no part of the world from which he was so pleased to receive recognition in his years of fame as Italy; and he received it in abundance, for the appreciation was mutual.

I will add a page here that was supplied for the present work by a friendly hand, a man who is as well known to thousands as Haeckel himself—Hermann Allmers, “the poet of the fens, chief of Frisia, and splendid fellow,” as Haeckel has called him. He died in the spring of 1902 at an advanced age. He met Haeckel in Italy, and tells the story in his verse and prose. Forty years after their meeting he wrote me that Haeckel was “the finest man he ever met.”

“TO ERNST HAECKEL.

Dost thou remember the magic night,

A night I never cease to see,

That brought us both to Ischia?

How smooth the boat sailed gently in,

How silent was the great broad bay

Unutterably noble and sublime,

In all its star-lit loveliness,

As sky and sea met in embrace.

With fairy-light the waters gleamed

As helm ploughed gently through the wave,

And overhead a deep red glow

Vesuvius from its larva poured.

We were yet strangers at the time,

One hour alone had each the other seen,

Yet something urged us both to speak—

To speak, anon, from heart’s great deeps.

To speak of all we held of worth,

All that had led us to the spot,

All the fair gifts of happy fate,

And the untoward accidents of life;

Of distant home, of fatherland,

Of the full days of beauty’s quest.

Hand clasped in hand we told our joy:

Need I recall it from the mist?

In fine of thy dear love thou told’st

And sacred silence fell on thee.

On moved the barque with leisured pace

Across the deeper silence of the bay.

Behind us vanished Posilippo

And Baja’s gulf and Cape Miseno.

As Procida passed slowly by

The gentle dawn stole o’er the night,

And Epomeo’s head was lit,

With the first rays of new-born sun,

And Ischia, nobler than our dreams,

Uprose before our wondering eyes.

Above, mantled in its own loveliness,

Calling us sweetly from the bay

Up to its gentle, vine-clothed heights,

Sat radiant Casamicciola.

How thou and I the glad days spent

Thou knowest well. And now?

Now all is ruin and decay,

A ghastly tomb. We’ll let it rest.

Think rather of the linkèd lives

We spent, and the whole joy of earth,

That never more will gladden us

While sun and stars gleam overhead.

What was it opened then our hearts?

What was it forged the golden chain?

It was—thou know’st it well, comrade—

The sailing on that magic night.”

“Yes, dear reader, whenever I let these verses and their splendid truth vibrate again in my soul—and how often and how gladly I do it!—I have to say, Such days thou shalt never know again—such happy entrance into another’s heart. And what a heart it was that bared itself to me with all it hid and would soon reveal! We were in a café at Naples, a copy of the Allgemeine Zeitung lying between him and me. It was in the best part of the spring of 1859. We both reached for it, and told our names, and the friendship was begun. ‘You must excuse me,’ Haeckel said, ‘I have to go to Ischia to-night by the market-boat.’ ‘To Ischia? That’s good: I am going there myself. ‘I am very glad, because I heard I was to be alone. It starts at nine o’clock.’ That was all that had passed between us before the crossing. What I have described in the above verses only began when we, the only Germans on board, made ourselves comfortable on the open deck. Before the journey was over we were intimate friends, and have remained friends in joy and sorrow to this moment, though the mental differences between us are enormous. However, Casamicciola brought us together in a wonderful way. We had common quarters, and always went out together for walks or botanising; we were never separated when we painted or drew, as Haeckel did with real passion. On the third morning, when we found some rare thermal plants in an almost broiling meadow and discovered nearly at the same spot the ruins of an ancient Roman bath, the remarkable coincidence affected us so much that we embraced each other joyously and dedicated the rest of our flask to them. We both felt that we could not do otherwise. So we pleasantly enjoyed the magnificent scene that lay at our feet from the height of Epomeo. We stripped off nearly the whole of our clothes, and dipped, in almost primitive nakedness, in the warm muddy streams that shot up out of the dark depths under a growth of tendrils and ferns. We shouted out, ‘How fine it is in these warm and beautifully shaded brooks! How delightful it must be in the ravines of Atlas! We must go there.’ We spent more than a whole day in the most marvellous ravines of Atlas, though neither of us had the least idea of them. But we determined to make the journey there, and sketched it out in detail, to be undertaken as soon as we left Italy. He contracted a perfect fever for travelling. We were four weeks in Pagano’s excellent inn at Capri with a few artists, and he completely lost himself with delight. He became intimate with the young artists; being hitherto surrounded by men of scientific interests, he had avoided them. The intermediary between Haeckel and them was myself. I liked no one better than genial artists. Now Haeckel was seized with a passion for painting landscapes day after day. He was especially interested in the most fantastically shaped rocks. On the other hand, he neglected his marine animals, and did not return to them entirely until he got to Messina, where he devoted himself to the radiolaria, which were destined to play so important a part in his work. Darwin, who was soon to dominate his whole thought, had little significance for him at that time, as the struggle for life had not yet been discovered. We rarely spoke of it, but talked constantly of Johannes Müller. He was Haeckel’s ideal, as long as I kept in touch with him. He also spoke often and generously of his university friends, Dr. W. D. Focke, who was his special botanical comrade, Dr. Dreyer and Dr. Strube, who were his chief friends at the university at Würtzburg. The ordinary life and pleasures of the student, and their heavy beer-drinking, were a torture to him; he avoided them as much as possible. Very often I could not understand how it was that I brought him to the highest pitch of gaiety, whereas on all his earlier travels, especially when botany was still his favourite science, he would, after the common meal, withdraw quietly with his books and plants to the solitude of his own room. Yet he could be the gayest of all. In fact, his hearty and wonderful laugh, in all notes up to the very highest, rings over and over again in the memory of any man who has once heard it; it is the frank laughter of a glad human heart. And whoever has seen the deep earnestness with which the great scientist threw himself into the study of the most arduous problems would be astounded to hear it.”

The Strait of Messina is the pearl of Italy. In my opinion it is finer than Naples. The huge volcano and the deep blue strip of water, that seems to be confined between the white coasts like some fabulous giant-stream, give a feeling of sublimity beside which the Bay of Naples seems but an idyll in the memory. The colours are more vivid; you think you would catch hold of the blue bodily if you put your hand in the water. It is a land of ancient myths. The Cyclops hammer their work in Etna. Scylla and Charybdis lurk in the Strait. Once, in the days of Homer, when the sun of civilisation still lay on a corner of Asia, a dim Münchhausen-world was lived here, such as we find to-day in the heart of Africa or New Guinea. But times changed. Zoologists came and fished with Müller-nets for tiny transparent sea-creatures in the gentle periodic currents, that may once have given rise to the legend of Scylla and Charybdis. There is no place more favourable for the purpose than the harbour of Messina. The basin is open only at one spot, towards the north. The westerly wind is cut off from the town by the mountains, and can do no harm. Even the detested southern wind, the sirocco, that lashes the Strait till it is white with foam, cannot enter. There is only the north wind that drives the water into the basin. The waves it brings in are full of millions of sea-animals, which accumulate in the cul-de-sac of the harbour. In fact, if the sirocco has previously been blowing in the Strait and gathered great swarms of animals from the southern parts at the mouth of the harbour, and then the north wind drives them all inside, the whole of the water seems to be alive with them. If you dip a glass in it, you do not get water, but a sort of “animal stew,” the living things making up more of the bulk than the fluid—little crystalline creatures, medusæ, salpæ, crustacea, vermalia, and others of many kinds.

It was at this classic spot that Haeckel would lay the foundation of his fame as a zoologist, by the study of a group of minute creatures that appealed equally to the æsthetic sense by the mysterious beauty of their forms. There can be little doubt that we can see in this, not only a fortunate accident, but also the play of some hidden affinity. In such a spot the artist in Haeckel could compromise with the zoologist. His æsthetic nature had revelled in landscape, peasantry, and song. Now the Müller-net and the microscope revealed a new world of hidden beauty that none had appreciated before him. In devoting himself to it he was still half engrossed in his quest of beauty; but the other half of him was rapidly attaining a mastery of serious zoology.

It is a common belief that æsthetic appreciation ceases as soon as we sit down to the microscope. There is the magnificent blue Strait of Messina. Your eye, embracing its whole length, drinks in its beauty in deep draughts. What will your microscope make of it? Its field can only take in a single drop of water, and this does not grow more blue when you thus analyse it. Let science go further afield: this is the land of beauty. All those doctrines of histology, embryology, and so on, built on the microscope, are thought to be poles removed from æsthetic enjoyment. They dissolve everything—man’s soft, white skin, the perfumed leaf of the rose, the bright wing of the butterfly—into “cells.” It is mere ignorance to talk in this way. Nature’s beauty is by no means so thin a covering that the microscope must at once pierce through it. Rather does it reveal to us in incalculable wealth a whole firmament of new stars, a new world of beauties, if we choose the right way to see them. Haeckel did choose the right way.

At his very first dips into the harbour of Messina, in October, 1859, he got certain curious lumps and strips of jelly. The local fishermen called them ovi di mare (sea-eggs). It was, in fact, natural enough to regard these inert creatures as strings of mollusc-eggs, when their real nature was unknown. But our young student already knew what they were. They were social radiolaria.

A Radiolarian.
(Lychnaspis miranda.)

The word “radiolarium,” from radius (a ray), means a raying or radiating animal. It is difficult for the inexpert to imagine the structure of one of these creatures. He must first put entirely on one side all the features that he usually associates with an “animal.” The radiolarian lives, moves, has sensations, breathes, eats, and reproduces, but in a totally different way from that we are accustomed to see. Its body consists essentially of a particle of homogeneous living matter. There is merely a firmer nucleus in the centre of it, and the soft gelatinous matter is thickened at the surface to form a kind of capsule. Otherwise there is no trace of any real “organ.” The little blob of jelly eats—but it has no stomach; it eats with its whole body, its soft, jelly-like substance closing entirely over particles of food and absorbing them. It breathes (with the animal type of respiration)—but it has neither lungs nor gills; the whole body takes in oxygen and gives off carbonic acid. It swims about—yet it has neither legs nor fins; the pulpy mass of its body flows, when it is necessary, into a crown of streamers or loose processes, that keep the body neatly balanced; when they are no longer required, they sink back into the gelatinous mass. We study the “histology” of these curious social-living creatures under a powerful microscope. As I have explained, the tissues and organs of the higher animals break up under the microscope into a most ingeniously constructed network of tiny living gelatinous corpuscles with a nucleus in the centre—the cells. But our radiolarian has no more got tissues composed of cells than it has stomach or lungs or any other organ. It is merely a single cell with a nucleus and a jelly-like body. Yet in this case the single cell is a whole individual, a complete animal, that lives, moves, eats, breathes, and so on. The radiolarian is, in comparison with the splendid cell-tapestry of the higher animals, a poor little atom of life. It must be put deep down in the animal series. What a vast distance! Above is man, built of myriads of cells woven into the most ingenious tissues and the most perfect organs for each function of life; below we have the radiolarian, in which a single cell must discharge all the vital functions, because its whole body is merely one cell. But there is another wonder. This tiny particle of living slime, floating in the blue waves at Messina, hardly more visible than a drop of spittle, has a most remarkable quality. It is able to assimilate a kind of matter that the chemist calls siliceous (flinty) matter—the stuff that forms, when it is crystallised in chemical purity, the well-known rock-crystal. This flint matter (and sometimes a similar substance) is then exuded again by the radiolarian—no one knows quite how—from its gelatinous body, and built into so beautiful a form that even a child will clap its hands and cry, “How lovely!” when it sees it through the microscope. We may put it that the radiolarian forms a coat of mail for itself from this siliceous matter: we may at the same time call it a float or buoy. The hard flinty structure serves to keep it balanced when it is swimming, just as when a loose piece of jelly attaches itself to a cork disk. Thus a round trellis-work shell is formed about the animal, and through the apertures it thrusts gelatinous processes that act as oars, and can be put forth or drawn in at will; outside this shell, again, may be all sorts of structures, such as zigzag shaped rods, radiating stars, bundles of streamers, and so on. It is a most wonderful sight. It is as if each class of these beings had its private taste, and, in virtue of a kind of tradition, built a different type of flinty skeleton from all the others. Here begins the peculiar artistic wizardry of these tiny and lowly creatures, that lifts them at once high up in the scale of animated natural objects with a great display of beauty. We find every possible variation of ornament within the limits of the particular type: an infinite number of crystalline and superb variations on the theme of trellis-work, stars, radiating shields, crosses, and halberds. They give an impression at once of human art-work, for there is nothing else in the whole of nature with which we may compare them. The radiolarian, therefore, is an animal of the utmost simplicity of bodily frame that, by some force or other, creates the highest and most varied beauty that we find anywhere in nature, living or dead, below the level of human art.

Haeckel’s good genius brought him to these radiolaria. Until the winter of 1859-1860 he knew very little about them. When a radiolarian dies its soft body naturally melts away and perishes. But the art-work of its life, the star or shield of flinty matter, remains; it either sinks to the bottom or is washed ashore, where numbers of them may accumulate. If a pinch of mud or sand from the shore is put under the microscope the observer will see lovely artistic fragments, and ask what is the meaning of the miracle. Ehrenberg, the venerable Berlin microscopist, was the first to have the experience. He was not in the habit of going to the sea himself, but had specimens sent to him, and found in them shells of the radiolaria. Though they were so small, their artistic quality seemed to him to be so great that he assumed they were built by very advanced animals of the star-fish or sea-urchin type. That there were unicellular protozoa with a simple gelatinous body and no higher organs he stoutly denied, and he had the support of his leading contemporaries everywhere. But his colleague, Johannes Müller, who fished in the sea himself, came across living specimens in the Mediterranean in the first half of the fifties. It appeared that they were really very lowly animals at least. Müller christened them the radiolaria, classified the fifty species that he discovered, and at his death left the subject well prepared for the first student who should go more fully into it. His final work on them did not appear until after his death, in 1858, the sunset-glow of his brilliant scientific career. Perhaps he would have gone more deeply into the mysteries he had encountered but for a curious accident. Just as he discovered the subject, two years before his death, he had a terrible experience. The ship in which he was returning from a holiday in Norway was wrecked. A favourite pupil of his was drowned, and he himself narrowly escaped by swimming to land. After that he could not be induced to enter a boat during his last trips to the sea, and so the thorough study of these most graceful inhabitants of the Mediterranean was abandoned. But when Haeckel fished at Villefranche with Kölliker of Würtzburg, and Müller was at Nice, he was urged by the master, as a kind of testamentary injunction, that “something might be done” with the radiolaria. And when he fished up a pretty crown of socially-united radiolaria on first rowing over the Messina harbour, he thought it would be a grateful offering to the memory of the dead hero of his zoological dreams to continue the study of the radiolaria. At once he seemed to enter the treasure-house of a fairy tale. When the campaign was ended in the Messina harbour in April, 1860, he had discovered no less than 144 new species, and each species proved a fresh master of decorative art. At the same time he studied the nature of the gelatinous body. Ehrenberg’s theory was destroyed for ever. Granting that there were certain difficulties (since explained away) in the way of admitting the existence of real unicellular creatures, he at all events gathered an enormous amount of new and helpful information as to the nature of these soft, almost organless beings and of the slimy living matter (called sarcode or protoplasm) of which they were composed. His mind matured rapidly in these quiet days at Messina, while his æsthetic nature was plunged in admiration of the beauty of the siliceous coats. The last scruple with regard to the old story of creation fell from him like the covering of a pupa. If a naked bit of slime like the radiolarian could form from its body this glorious artistic structure, why may not man also, as he paints his pictures under the glow of Italy’s colour, be merely a natural being, of like texture to the radiolarian? And if this radiolarian had in its life built up the crystalline, rhythmic structure, why may there not be merely a difference of degree, not of kind, between the “dead” crystal and the “living” radiolarian?

In May, 1860, Haeckel returned from Messina to Berlin. He brought with him splendid drawings of the perishable body of his treasures, numbers of prepared specimens, and whole bottles full of their imperishable shells. On the 17th of September, 1860, he made the first communication of his discoveries to his colleagues in the zoological section of the Scientific Congress at Königsberg. Virchow was amongst his admiring audience. On the 13th and the 20th of December in the same year Peters read a short account in the Berlin Academy of Science that drew more general attention. He set to work on a fine monograph, with splendid plates and with all his conclusions in the text. Before it was finished, however, he had a number of personal experiences and changes of mind. Gegenbaur had in the meantime been appointed Professor of Anatomy at Jena. Before he started for Italy, Haeckel had visited his friend at Jena during the celebration of the third centenary of the university. “We spent a very happy time there,” Haeckel wrote afterwards, “enjoying the beautiful prospect (from the heights of the Saale valley) and the Thuringian beef-sausages.” Now there were more serious things to discuss. Gegenbaur’s lot had once seemed to him a kind of model. Now a part of it was fulfilled: he had been to Messina. Meantime Gegenbaur had advanced a station. Haeckel wanted to follow him, and get a position at Jena. There was no such thing as a professorship of zoology or a zoological institute there, but all that might—nay, must—be changed some day. What Gegenbaur was doing left plenty of room for another chair to be set up. And to be with his best friend!

In March, 1861, Haeckel completed the Dissertatio pro venia legendi at Jena that he had quickly decided on. It dealt, of course, with his new field: the limit and the system of the animal group to which the radiolaria belonged, the rhizopods. He was immediately appointed private teacher at Jena, and found himself in the lovely valley of the Saale, beneath the mountain about whose summit the red rays lingered. He had been drawn from Berlin to Messina to find a home—a home for ever—in the increasing stress.

In the following year, 1862, the official position of Extraordinary Professor of Zoology was created, and this brought him close, even externally, to Gegenbaur. Everything was, it is true, in a very primitive condition at first. In August he married Anna Sethe—a sunny dream of fresh young happiness. In the same year he published his Monograph on the Radiolaria, a huge folio volume with thirty-five remarkably good copperplates, such as our more rational but slighter technical methods no longer dare produce. Wagenschieber, of Berlin, the last of the fine scientific copper etchers, had been in constant personal touch with Haeckel, and reproduced his original drawings in masterly style. With this work Haeckel was fully established in his position as a professional zoologist. It is still one of the finest monographs that was issued in the nineteenth century; from the literary point of view, also, it was one of the purest and most lucid works of its kind, full of great and earnest thoughts, and without any bitterness—a work, perhaps, that Haeckel has not since equalled. The most influential and official scientists of the time had to respect this work: possibly with the sole exception of the aged Ehrenberg, to whom it dealt a deadly blow in this department, without, of course, undervaluing his great antecedent services. He never even studied it sufficiently to be able to quote the title of it correctly.

Nevertheless, a flame broke out at one spot in this monograph. In a very short time Haeckel’s whole figure would stand out in the red reflection of its glow—a figure really great, solitary, suddenly deserted by all the bewigged and powdered professors—Haeckel himself, as the world has come to know him.

CHAPTER IV
DARWIN

We still celebrate, at a distance of centuries, the return of the birthday of great men. In reality it is a mistake. We ought to celebrate the hour when not merely life, but the idea of their life, quickened them. That is the really important birth that calls for commemoration. Luther’s real birthday was when he nailed his theses to the church door. Then was born the Luther that belongs to the world. Over the world-cradle of Columbus shines, not the trivial and evanescent planet given in his horoscope, but the little red flickering star of Guanahani, the light that he saw from the shore on the night before he landed on an island of the New World.

Life is a voyage of discovery to the man who passes through it. He looks out with his child-eyes and discovers the world—at the bottom, discovers only himself. But one day a greater veil is torn from before his self. Genius, the greater I, stirs within him like the butterfly in its narrow pupa-case. For the world at large that is the hour when the great man is born who will leave his mark on it.

Haeckel’s biography only begins on a certain day, if we look at it rightly and broadly. Until that day he is merely a young man, an outgrowth from a rich old civilisation: a young man who has felt in him a struggle between artistic and scientific tendencies, like so many: who has vacillated between the choice of a “paying profession” and research for its own sake, and has decided for the former, like so many: who has chosen zoology, and begun to work hard on professional lines at his science: and who has been told prophetically that he will one day do something, though along a line where much has been done already. In the whole of this development we have as yet no indication of the real tenor of his life.

It comes first with the name of Darwin. The arabesque of a very different life begins to blend with that of his own.

In the February of the year in which Haeckel was born (1834), twenty-eight years before the point we have arrived at, Charles Darwin was on a scientific expedition to South America. There is a romantic element in the earlier story of this journey. The naked Fuegians had stolen a boat from an English Government ship that was engaged in making geographical measurements, towards the close of the twenties, on the wild coast of Tierra del Fuego. FitzRoy, the captain, arrested a few of the natives, brought them on board as hostages, and in the end took them with him to England. They were to be instructed in morality and Christianity and then taken back to their people, in order to introduce these elements of civilisation, for the advantage of shipwrecked sailors or distressed travellers who might fall in with them. We feel a breath of the spirit of Rousseau in it. As a fact nothing came of the device. The good Fuegians were clothed and improved by civilised folk for a year or two, returned home, immediately abandoned their trousers and their Christianity, and remained naked savages. But the bringing home of these hostages led, in the early thirties, to a new expedition of FitzRoy to Tierra del Fuego. The Government directed him to draw up further charts, and he looked about for a man of science to accompany him.

The man proved to be Charles Darwin, then in his twenty-second year.

The son of a prosperous provincial physician, he had begun to study medicine without much success, and was transferred to theology, only to find after three years of study that he was as little fitted to become a country clergyman as a country doctor. He had an unconquerable love of scientific investigation. He collected all kinds of things, and desired to travel, without any very clear idea of his destiny. A chance introduction came to the young man as a godsend, and he joined FitzRoy’s expedition to South America. Once more, it was this journey that made him “Darwin,” the mighty intellectual force in the nineteenth century.

Darwin found an idea in South America. You have to examine it very closely to appreciate it clearly. Let us recapitulate very briefly the hundred years of zoology and botany that had gone before.

In the eighteenth century Linné drew up, for the first time, a great catalogue of plant and animal species. Each species had a solid Latin name, and was provided with its particular label, by which every representative of the species could be recognised at once. Then the species were bracketed together in larger groups, and a general system was formed. It was an immense scientific advance, and is still generally appreciated as such. But we have to make one reserve. It is not man that separates things; nature, or rather God who created nature, has already distinguished them. In this respect zoology and botany are of God. The various species of plants and animals are something firmly established by God. Take the polar bear, the hippopotamus, the giraffe, or a particular species of palm, or vine, or rose. There they are, and all that man has to do is to learn their specific characters in order to determine and name them.

Behind all this we really have the ancient idea of the Mosaic story of creation. God made the animals and plants, species by species, put them in their places, and said to man, “Name them as you think fit, classify them, putting the like together and separating the unlike.” So God spake to Adam when he stood before him, naked as a Fuegian. Linné comes on the scene some six thousand years afterwards to set about this naming and arranging in earnest. But that does not make much difference. There are the species created by God. They have ceaselessly reproduced themselves since the days of Paradise according to the command to increase and multiply, each one in its own kind, so that the polar bear has only begotten polar bears, the giraffe giraffes, the hippopotamus hippopotami. Thus, in spite of death, the primitive Paradise is still there, and Linné, the official professor at Upsala, with his venerable wig and embroidered coat, can take up the work of the naked Adam with a good conscience, and finish what the patriarch had not been able to do.

Linné died in 1778 (about the time when Goethe was beginning the Iphigenia and Wilhelm Meister) in the full fame of all these achievements and all his hypotheses from the giraffe to God. Fifty years elapsed between this and Darwin’s voyage; but in those fifty years the following process is accomplished:—

An increasing number of bones and other relics of animal species, that exist no longer, were dug out of the earth. In South America the skeleton was found of a giant-sloth, the megatherium, the remains of a kind of animal, larger than the elephant, that no traveller could find living in the country. The famous mammoth-corpse came to light in the ice of Siberia; an entirely strange elephant with curved tusks and a red woolly coat. Ichthyosauri were found in the rocks in England, and so on. All these “extinct” species had to be named and arranged in the system. A special scientific indication was put on them, which means “extinct.” But this was not enough for thought—which cannot be “entirely dispensed with,” as some one well said, even in exact science.

Where did these extinct species come from? What is their relation to the Creator? Were they created long ago in Paradise with the others, and afterwards conveyed in the ark, only to disappear in the course of time? And what was the cause of their disappearance? Must we conclude that part of what Adam saw was not available for Linné and his pupils? These four remains, a few bones here and there, do not tell us much about them.

Therefore, species may perish: many of them have perished.

There was something new in this, something that obscured the clear lines of earlier science. However, a way of escape was found. It was claimed that these grotesque monsters—ichthyosauri, megatheria, mammoths, &c.—represent an earlier creation, with which Adam had nothing to do. Cuvier developed the theory in his grandiose way in 1812. Before the creation of the animal and plant species that Adam found in Paradise there was a long series of periods in the history of the earth, each of which had its own animal and plant population. It was in one of these periods that the forests grew which we find fossilised in our coal. In another the ichthyosauri, gigantic lizards, filled the ocean. In a third the hideous megatherium dragged along its huge frame, and so on. It is true that there is nothing in the Bible about these ancient and extinct periods; but the Mosaic verses move quickly—they press on to come to man. The repeated creations of the animal and plant worlds are summed up in a single one. We must read something between the lines.

Apart from that, everything is clear. Hence the ancient species were made fixed, solid, and unchangeable by God just like the later species that Adam found in Paradise, and that still exist. Without the will of God they could no more have died out than the actual ones; and there were no human beings there to destroy them. But the divine action intervened. At the end of each of these old-world periods a terrible spectacle was witnessed. The heavens poured out their punishing floods; the seas were heated to steam by fiery masses of rock that were summoned by the divine power from the bowels of the earth. In the course of a single day the carboniferous forests were swallowed up; the megatheria disappeared, legs uppermost, like flies in butter, in the sand dunes of the terrible floods.

The might of the creative act was equalled by the might of the destruction. The science of these vast new creations and divine revolutions before Adam’s birth was called geology. It lived in peace with Linné’s theory of fixed species. Its parent, Cuvier, was so great a genius that it seemed quite impossible that he had made a mistake. Before twenty years were out he was, in the opinion of a contemporary and equally able geologist, declared to be certainly wrong on one point.

Lyell wrote a magnificent work in which he proved, from the point of view of scientific geology, that the whole story of these terrible revolutions was a fiction. There are no such sharp sections in the early history of the earth. Everything goes to show that throughout the whole period of the earth’s development the same natural laws have been at work as we find to-day. It is true that the relative positions of sea and land, hill and valley, forest and desert, have often changed; but very, very slowly, in the course of millions of years. A single drop of water, constantly falling, will hollow out a stone. In these millions of years the water has swept away rocks here, and formed new land by the accumulation of sand there. In these millions of years the sand has been compressed into the gigantic masses that tower above us to-day as sandstone mountains; they are formed of sand that was originally laid like mud, layer by layer, on the floor of the ocean.

It was all very plausible; it seemed to picture an eternal flow of things in which there was no room for God. The changes in the earth’s surface were easily brought about without catastrophes, in the course of incalculable ages. God was excluded from geological discussions of the formation of hill and dale. And when it was fully realised, it brought the question of species to the front once more.

It was impossible to retreat simply to Linné’s position. Lyell by no means denied Cuvier’s various periods in the earth’s development as such. He believed, moreover, that the plant and animal populations were different in these epochs. When the forests flourished which have formed the mass of our coal-measures there were no ichthyosauri; when the ichthyosauri came there were no longer any carboniferous forests; with the ichthyosauri there were no megatheria, and the last ichthyosaurus was extinct before the megatheria arrived. All that Lyell rejected was the great divine catastrophes. But when these were abandoned, it was no longer possible to attribute the “end” of the extinct species to a divine act. We were faced with the slow and natural conversion of terrestrial things in the course of endless ages.

Species must have been liable to be destroyed by purely natural causes. The catastrophes were abandoned, yet species had been destroyed. And when that was granted—it was the devil’s little finger—a further conclusion was inevitable. If species have died out slowly and naturally in the history of the earth, and new species have made their appearance at the same time, may not these new species have arisen slowly and naturally? Suppose these simple and purely natural causes, that had brought about the extinction of certain species, had been for others the very starting-point of development? In one word: if the extinction was not due to a mighty divine interference, was it not conceivable that the origin also may not have needed such?

One more deduction, and the demon of knowledge had hold of the entire hand. May not this natural extinction and natural new-birth have been directly connected in many cases? As a fact, some of the species had been wholly extirpated. But others had provided the living material of the new arrivals; they had been transformed into these apparently new species. That was the decisive deduction. It did away with the need of any sudden creation. It merely made a claim that was appalling to the Linnean principles: namely, that species may change. In the course of time and at a favourable spot one species may be transformed into another.

Another fairly obvious deduction could be made. Who brought about the transformation? Lyell proved that, without any catastrophes, terrestrial things are constantly changing—the water and the land, the mountains and the valleys, and even the climate. In this gradual change the environments of living things were at length altered to such an extent that they were bound to cause a change in the organisms. However, different species reacted in different ways. Some gradually died out. Others adapted themselves to the new conditions; just as, in human affairs, one race breaks down under changed conditions while another rises to a higher and richer and new stage on that very account. No creation! Merely transformations of species, development of new forms from older ones by adaptation to new, naturally modified conditions. Even zoology and botany were without the finger of God from the earliest days.

Of course there was no trace of these latter deductions in Lyell. But they pressed themselves with an irresistible and decisive force on the mind of one of his first readers, Darwin.

He took Lyell’s book with him to South America. Step by step the logic of it forced him to admit that this was what must have taken place somewhere. First the idea of “extinct species” became a concrete picture to him there, a sort of diabolic vision. The whole substratum of the pampas is one colossal tomb of strange monsters. The bones lie bare at every outcrop. Megatheria, or giant-sloths, as large as elephants, and with thighbones three times as thick as that of the elephant, able to break off branches in the primitive forests with their paws: armadilloes as big as rhinoceroses, with coats as hard as stone and curved like barrels; gigantic llamas, the macrouchenias, compared with which the modern specimens are Liliputians; mastodons and wild horses, of which America was entirely free even in the days of Columbus, and lion-like carnivores with terrible sabre-teeth. There they all are to-day—extinct, lost, buried in the deserted cemetery of the pampas-loam.

When the young Darwin stood by these groves, like Hamlet, he did not know how closely this ghost-world came to our own day. At that time the armour of the gigantic armadillo, the glyptodon, that had formed shelters over the heads of the human dwellers in the pampas, like Esquimaux huts, had not yet been discovered. The cave of Ultima Esperanza in Patagonia had not been searched, and no one had seen the red-haired coat of the sloth as large as an ox, the gryptotherium (a relative of the real megatherium), cut by some prehistoric human hand, amongst a heap, several yards deep, of the animal’s manure—in such peculiar circumstances as to prompt the suggestion that the giant-sloths had been kept tame in the cavern, as in a cyclopean stable, by prehistoric Indians. Darwin thought the remains were very old, though this by no means lessened the inspiration.

As our geological Hamlet speculated over these bones of extinct monsters, the ideas of Linné and Cuvier struggled fiercely in his mind with the new, heretical ideas inspired by Lyell. How was it that these ancient, extinct animal forms of America resembled in every detail and in the most marked characteristics certain living American animals? Before him were the relics of past sloths, armadilloes, and giant-llamas. In the actual America, also, there were sloths, armadilloes, and llamas, though with some difference. And nowhere else on earth, either in past or present time, were there sloths, armadilloes, and llamas. Cuvier had replied, God had pleased to create those ancient megatheria, glyptodons, and macrouchenias of America. Then, one day, he sent his destructive catastrophe, and swept them all away, as a sponge goes over the table. Then, in the empty land, he created afresh the sloths, armadilloes, and llamas of to-day. But why had God made the new animals so like the old that the modern zoologist has to class the megatherium in the same narrow group as the actual sloth, the ancient glyptodon with the modern armadillo, and so on?

Darwin, who had studied theology, was unshaken with regard to God himself. However, something occurred that occurs so often and with such good result in the history of thought. It appeared to him that the notion of a direct creation is by no means the simplest way of explaining things, but the most puzzling and complicated. Darwin believed in Lyell. There had been no destructive catastrophe at all to sweep away the megatherium and its companions. They had disappeared gradually, by natural means. Was it not much more rational to suppose that the actual sloths and armadilloes came into being gradually, by natural means? Part of the old animal population had not perished, but been transformed into the actual species. There was a bond of relationship between the past and the present. One or other grotesque and perhaps helpless giant form may have completely disappeared in the course of time. But the golden thread of life was never entirely broken. Other and more fortunate species had preserved the type of the sloth, the armadillo, and the llama; they had developed naturally into the living animals of America. God might remain at the groundwork of things. He had launched matter into space, and impressed natural laws on it. But these sufficed for the further work. They created America. They developed the mammal into the sloth and the armadillo in the days of the megatherium and the glyptodon. They maintained these types in the country, in a straight line of development; the progressive principle of life bringing about the extinction of certain forms, and transforming others by a more fitting adaptation to their environment.

Darwin always looked back on this first conflict of his ideas in presence of the dead shells and bones of the ancient pampas animals as an hour of awakening. It was the birth of his humanity in the higher sense. It is of interest to us because it coincides exactly with the date of Haeckel’s birth in the ordinary sense.

In Darwin’s fine account of his voyage, which is mostly arranged in the form of a diary, we find a passage written on the east coast of Patagonia on January 9, 1834, and the next on April 13th. In the meantime the ship had made a short zigzag course, which is spoken of in another connection. But the interval between the two dates is taken up with a passage on these gigantic animals, the reasons for their extinction and the striking fact of their bodily resemblance to the living animals of South America. “This remarkable resemblance,” we read, “between the dead and the living animals of one and the same continent will yet, I doubt not, throw more light on the appearance of organic beings on the earth than any other class of facts.” This is clearly a summary of Darwin’s deepest thoughts at the time. Haeckel was born on February 16th of the same year, 1834. Thus the bodily birth of one of the two men whom we conceive to-day as Dioscuri coincides with the spiritual rebirth of the other. But it would be nearly thirty years before they would meet in spirit never to part again. At the very beginning of their acquaintance Darwin wrote a letter to Haeckel (October 8, 1864) in which he speaks of the earliest suggestions of his theory. The Hamlet-hour comes back vividly to his memory. “I shall never forget my astonishment when I dug out a gigantic piece of armour, like that of a living armadillo. As I reflected on these facts and compared others of a like nature, it seemed to me probable that closely related species may have descended from a common ancestor.”

However we take it, Darwin then saw for the first time that his difficulty about the mutability of species was from the first, in his own mind, a difficulty about God. He began his doubts with the ancient armadillo; he ended with God.

On the return journey from South America, which amounted to a circumnavigation of the globe, the struggle was renewed at the Galapagos islands. Volcanic forces had raised these islands from the bed of the ocean in comparatively recent times. They were, therefore, bound to be a virgin province at the time. Now, however, the walls of the crater were clothed with vegetation, birds flew after insects, and gigantic turtles and lizards lived on the shores. Whence did these plants and animals come? Darwin examines them. They have an unusual appearance, and seem to point to America. Yet not a single species is now wholly American; each has its peculiarities. An historical controversy arises over the islands, and men range themselves in parties once more. Empty islands emerge from the blue waters. How are they to be populated? There are two possibilities. One is that God has created the animals and plants—Galapagos animals and plants. But in that case why has he created them entirely on the American model, while diverging from it in small details? The second possibility is that the animals and plants were brought by the current or the wind from the neighbouring American coast; they are American plants and animals. After landing on the islands, they adapted themselves to their new surroundings, and were altered. Hence both the resemblance and the difference. The theory assumes, of course, that species are mutable. If that is so, we can explain everything—without God.

But the greatest and tensest struggle began when Darwin returned home. He approached the most audacious, but most striking fact, for his purpose. Up to this the question had been whether new species were produced by God or by natural necessity. Now a third element was introduced, man himself. He also alters species, as a breeder of pigeons, rabbits, sheep. He has done it with success for ages—only the Linnés and Cuviers had not noticed the fact. How does he accomplish it?

A breeder desires to give his sheep finer wool. He examines the wool of a thousand sheep. The difference between them is so slight that it is of no practical consequence. But the farmer selects the male sheep out of the thousand that has the best quality of wool, and the corresponding female. He crosses the two. Their young have wool of a slightly improved quality, and he picks out the best amongst them once more for crossing. He continues this through several generations. At last, with his continuous selection and crossing, the quality of the wool increases so much that any one can recognise it at once, and it has a distinct cultural value. In this way improved races of animals and large numbers of fine flowers have been produced by breeders: by artificial selection of the fittest to reproduce in each generation. This was done by man—not by God, not by nature in remote times, but under our very eyes, by man.

Now for an analogous process without man. Let our sheep live wild in any country. No human breeder has any interest in them: God does not seem to interfere with them. They live on and on, for thousands of years, generation after generation. Here again, in the wild state, we find the same slight variations in the quality of the wool. One sheep has a thicker coat than another. For thousands of years the fact is without significance. Then occurs a slow change of the environment. The climate becomes colder. Perhaps an ice-age sets in, such as our earth seems to have passed through many times. There are two alternatives. A very hard winter may set in at once and all the sheep perish, because their woolly coat is too thin in all cases. That would mean the extinction of a whole species. But the severe cold may come on gradually. The winters are more trying. So many sheep perish in the first winters; but so many others survive. Which will survive? Naturally, those that happened to have the thicker coats. Those alone live on to the spring, and reproduce. The following year the coat is thicker all round, as the lambs all came from relatively thick-coated parents. The winter decimates them again, and the thickest coated survive once more, and so on. The pressure of external conditions, the “struggle for life,” selects just as man does. Only the best adapted individuals survive and reproduce.

The whole earth is a vast field of splendid adaptations. The tree-frogs are green because only green frogs are preserved; all the others are destroyed. The arctic hare is white on the snow, the desert-fox yellow. For a thousand reasons in the course of the earth’s development these backgrounds—white, yellow, green; snow, desert, forest, &c.—have themselves been constantly changing under the action of Lyell’s changes in the crust of the earth. Hence constantly fresh adaptations, with a certain percentage of complete extinctions. In these ceaseless new adaptations we see a picture of an eternal progressive development. Always a finer selection: always better material: natural things always selecting and being selected. Man is superfluous in this world-old, eternal process. And God, too, is superfluous.

That was Darwin’s last and decisive thought. Divine action was excluded from the whole province of animal and plant species. It does not matter whether or no the shrewd idea of natural selection solves the whole problem. Why speak of “whole,” when all problems are really unfathomable? He left open the question of the origin of the first slight variations, the first increase in the fineness or thickness of the sheep’s wool, for instance. He left open the question of the inner nature of the process—and a good deal more. But these things did not affect the great issue.

What Darwin did was to show for the first time how we might conceive the natural evolution of species; to suggest that the miracle of the purposive adaptation of organisms to their environment could be explained by purely natural causes without introducing teleological and supernatural agencies to bring the disharmony into harmony. The older mind and logic had seen the action of God everywhere; the new thought and logic were gradually restricting his sphere. Darwin took away a whole province from the teleologist when he merely set up the idea of selection. He towered above himself in that moment. Natural philosophy wrested zoology and botany from the hands of Linné and Cuvier. It destroyed the old idea of a design in the interest of natural law and the general unity of nature. “Allah need create no more.” We cannot emphasise it too much: it was the conceivability that settled the question. Darwin had shown that “it might have been so,” and this possibility stood for the first time in zoology and botany opposed, with all the weight of logic, to the other theory, which was no more understood, but was supplied by imagination to fill a gap—the idea of a special creation of each animal species, the idea that the green tree-frog, had been created amongst the foliage just as he was. The feebler fancy gave way to the better. In this concession lay whole sciences that would have to be entirely transformed on the strength of Darwin’s achievement.

Narrow-minded folk have tried to make light of the mere “possibility,” creating a distinction between truth and logical theory. As if all truth were not solely in the human mind! What an age can conceive is true to that age. There is nothing higher in the bounds of time and the development in which we are involved. All truth and science began for humanity in the form of possibilities. Copernicus’s theory was only a possibility when it first came. All that we call human culture has come of the putting together of thousands upon thousands of these possibilities, like so many stones. It is no use raising up against it the figment of “absolute truth.” The main point was that Darwin raised the conceivability of a natural origin of species by the modification of older forms, which were driven ceaselessly to new adaptations under the stress of the struggle for life, to such a pitch that the older possibility of a creation of each species and its deliberate adaptation by supernatural action sank lower and lower. It was a pure conflict of ideas; the greater overcame the smaller—now smaller.

Darwin’s work, the Origin of Species, was published on November 24, 1859, after twenty-five years of study. He kept the theory of selection to himself for more than twenty years. The whole of the young generation from the beginning of the thirties, to which Haeckel belonged, grew up without any suspicion of it. Apart from the constant ill-health that hindered his work, Darwin was tortured with anxiety lest he should be treated as an imaginative dilettante with his heretical ideas. In the scientific circles of the middle of the century one was apt to be disdainfully put down as a windy “natural philosopher” if one spoke of “the evolution of animal and plant species” and the like. The word had become the scarecrow of the exact, professional scientific workers; much as when commercial men exclaim, “Dear me, the man’s a poet.” Hence Darwin wanted to provide a most solid foundation of research for his work, and then to smuggle it into the house like a goblin in a jar.

He took his task so seriously that, as Lyell afterwards wrote to him, he might have worked on until his hundredth year without ever being ready in the sense he wished. Chance had to intervene, and bring forward one of the younger men, who almost robbed him of the title of discoverer. Wallace arrived independently at the idea of selection, and he was within a hair’s breadth of being the first to publish it. The aged scholar at Down had to come forward. Then the great book was published, and Wallace disappeared in its shadow.

In Darwin’s opinion it was only a preliminary extract, and he added many supplementary volumes as time went on. As a fact it was so severely elaborated that even the thoughtful layman, possibly with a sympathy for the idea, was almost, if not wholly, unable to digest the proofs. It had to be “translated” for the majority of Darwin’s educated countrymen. On the other hand, this mass of facts was partly strange and new to the professional biologists. What did so many of the museum-zoologists know, for instance, of the results and problems of the practical breeder? “That belongs to the province of my colleague who teaches agriculture, not to mine.” His proofs were taken indiscriminately from zoology, botany, and geology. But at that time it was woe to the man that mixed up the various branches of research. The professor of zoology could not control the botanical material, and vice versâ. There was, in addition, the general dislike of the natural-philosophical nucleus. It was impossible to suppose that this very individual book, transgressing every rule, should at once meet with wide encouragement, or even ordinary appreciation.

In England Darwin’s repute as a traveller and geologist, and the personal respect felt for him, had some effect. Then came a small circle of friends, Hooker, Huxley, even, to some extent, the aged Lyell, who had seen the manuscript before publication, and had at once started a more or less brisk propaganda. In the first six months three editions of the work were sold, so that it was read by a few thousand men. As a rule there was at that time less dread of “natural philosophy” in England than elsewhere. But pious minds were alarmed at the “struggle against God” that was based on the exact data of zoology, botany, and geology.

Darwin had made that the salient point, as a glance at the work shows, since he closes with a reference to the Deity. He said it was a “grand” view of the Creator to suppose that he had created only the first forms of life on the earth, and then left it to natural laws to develop these germs into the various species of animals and plants. It was prudent to restrict the theistic conflict. God was merely excluded from the origin of species. Natural selection did not apply to the further problem of the origin of the primitive life-forms and of life itself. Theism could retain them. There was something soothing psychologically in the phrase, which was often attacked subsequently, and did not represent Darwin’s later views. It was characteristic of Darwin’s gentle disposition.

He did not start out from the position that God does not exist, and that we must, at all costs, seek natural causes for the origin of things. He had not abandoned the idea of the clerical profession because he had lost belief in God, but because he had more attraction for catching butterflies and shooting birds. Still a firm theist, he had been convinced, as a candid geologist, by Lyell’s demonstration that God had had nothing to do with the moulding of hill and valley or the distribution of land and water. As a candid zoologist and botanist he had then convinced himself that the analogous changes in the animal and plant worlds had needed no divine intervention.

As yet, however, he saw no reason to draw more radical conclusions. He sought, as far as honour permitted, a certain peace of thought by asking whether this indirect action of the personal Ruler over such vast provinces did not enhance the idea of him instead of detracting from it.

Goethe would have been prepared, on his principles, to recognise the step taken in the direction of natural law as a victory for our increasing knowledge of and reverence for the Deity. For him a natural law was the will of God; if natural selection created species, he would have seen merely the will of God in selection. But Darwin had not yet advanced so far, and still less could this be expected in his pious readers.

However, we find a curious confession a few paragraphs before the theistic conclusion of the book. It runs: “Light will be thrown on the origin and history of humanity.” Light, that is to say, from the theory of the transformation of species by natural selection. The words contained the promise of a new twilight of the gods. In the innocent days, when the Creator stood in person behind each species of animal and plant, Linné had seen no great innovation in his defining man as a definite species, the highest species of mammal. God had created the polar bear and the hippopotamus, Genesis said, as well as man. That man had transgressed the command in Paradise, fallen into sin, needed salvation, and so on, was another matter altogether. With Darwin the innovation was incalculably important.

On his theory the various species of animals had been developed from each other, without a new creative act. If man was an animal species in this sense, he also must have originated from other animals; and that would be bitter. The phrase shows that Darwin already saw clearly, and had abandoned his belief in a special creation of man. But this point was bound to make more bad blood than all the rest put together. God, now restricted to the direct production of the first living things, had lost man as well as the animals. Moreover, whatever interpretation was put upon the Mosaic narrative, the very source of theistic belief, the Bible, was called into question. How had we come to know of this story of divine creations? By the Bible, the vehicle of revelation. But this Bible was the work of man, and man was now well within the bounds of nature, from which God had been excluded. How could he learn anything from revelation? The biblical writers had clearly only made conjectures. Some of them—with regard to Adam, for instance—were certainly incorrect. There was nothing in the Bible about evolution by means of selection. Indeed, was not the whole picture of a creating Deity an error? These thoughts were bound to press upon the religious mind with all their logical force. When they did so, the very foundations of theology became insecure, to a far more serious extent than Darwin’s moderate conclusion suggested. When the book fell on this contentious ground, it was bound, even if it were only read in the last two pages, to provoke vast waves of hostility against its heretical zoology and botany, especially in England.

Haeckel was in Italy when the work—the work of his life, too, as the sequel shows—was published. We have seen where he was: in sight of the blue sea, penetrating for the first time into a special section of zoology, the radiolaria, and making it his own. He was far from theorising, for the first years of reality were upon him. He returned to Berlin at the beginning of May, 1860, bringing his study of the radiolaria, and resolved to publish it in comprehensive form. Here he learned for the first time that a “mad” work by Darwin had appeared, that denied the venerable Linnean dogma of the immutability of species.

German official science was now invaded from two sides at once. Haeckel had returned like a new man from the freshness of Italy; and Darwin’s work, translated by Bronn, was bringing some slight extract of the English student’s thoughts, like a draught of old golden wine. They were bound to meet this time.

The aged Bronn, a German naturalist of distinction and merit, had found the Origin of Species interesting enough, at least, to deserve the trouble of translation. But his interest in it was very restricted. He was one of the thoughtful students of the days following Cuvier, and was not of the kind to pin his faith to one man. The appearance of the plant and animal species in the various terrestrial periods, so sharply separated by Cuvier himself, showed unmistakably an ascent from lower to higher forms. The fish is placed lower in the system than the mammal. At a certain period there were fishes living, but no mammals as yet. At another period the only plants on the earth were of the decidedly lower group of the cryptogams (ferns, shore-grasses, club-mosses), and these were succeeded by pines and palm-ferns, and finally by the true palms and foliage-trees. Cuvier’s theory of creation had to take account of this. Agassiz, who held firmly to the fresh creation of species in each new epoch, conceived the Creator as an artist who improved in his work in the course of time. Each new achievement was better than the preceding. It was rather a curious idea of the Creator!

Photograph of Marble Bust by G. Herold.

Others, who did not venture to use the idea of Deity quite so naïvely as Agassiz in zoology and botany, conceived a “law of development” within life itself. It was a time when belief in a “vital force” was universal. Living things had their peculiar force, which was not found in lifeless things. The life-principle might be at work in the law of development. It would raise living things higher and higher in the succeeding geological epochs. It was a vague theory, though it purported to cover not only the fact but the machinery of development. In the course of ages it brought about the appearance of new species. Those who held this idea of an immanent law of evolution rejected the older notion of a personal Deity, putting in an appearance suddenly at the beginning of the secondary period and creating the ichthyosauri “out of nothing.” They looked upon Cuvier’s catastrophes, to which Agassiz still clung, with a touch of Lyell’s scepticism. The “law of evolution” had been the deus ex machina of the long procession of life-forms. One day a fish ceased to give birth to little fishes in the manner of its parents. The “law of evolution” was at work in its ova, and suddenly little ichthyosauri were developed from them. Thus, again, a lizard was believed to have engendered young mammals one day. One student would hold that the transition was quite abrupt in this sense. Another would think it more gradual, and approach the idea of a slow transformation of a fish into a lizard, and a lizard into a mammal, or a tree-fern into a palm-fern, and this into a true palm. At the bottom they were all agreed that the whole inner law of evolution had nothing whatever in common with the other laws of nature and was not subordinate to them. They did not hold an evolution in harmony with the great mechanism of natural laws. Their principle got astride of natural laws at certain points, like a little man, and turned them in this or that direction.

Very little philosophic reflection was needed to show that they had merely replaced the Creator with a word. The older Dualism remained. On one side was the raw material of the world with the ordinary natural laws; on the other side a lord and master, the law of evolution, playing with the laws as it pleased, and moulding the material into new life-forms in an advancing series. It is true that they no longer pictured to themselves a venerable being with a white beard creating the ichthyosauri, but the finger of God remained in the law of evolution, attenuated into a special and spectral form. The God that acted from without was banished, but the “impulse from within,” reduced to a mere skeleton in substance, was put upon the throne.

The advocates of the law of evolution had assuredly done much in preparing the way for Darwin, as they had insisted that certain advances in detail were undeniable and built up theories from the chaotic material provided by special research—especially seeing that some of the ablest naturalists of the time were amongst them, who determined to retain speculation in zoology and botany. But, on the other hand, it cannot be questioned that the confused nature of their fundamental idea, which, in fact, was not far removed from the theological notion of the vital force, gave the rigid and “exact” academic workers an apparent right to reject all speculation on the possibility of an evolution of species as an unscientific dream. The aged Bronn was in 1860 one of the most prudent and sober of the advocates of the inner principle of evolution. He candidly acknowledged that Darwin had struck a severe blow at the great idea of his life, on one side at least. Darwin’s work not merely dismissed God to the wings as a personality, but even left no room for the finger of God, for his spiritual writing on the walls of the living world. It found evidence of natural laws alone. From them came, if not life itself, at all events selection, adaptation, and evolution by virtue of this increasing adaptation—the higher advance that converted the fish into a lizard and the lizard into a mammal. The fine old worker, with an age of indefatigable labour behind him, though he had not got beyond the idea of a “law of evolution,” looked on Darwin with a mixture of fear and admiration as he cut into the very heart of these problems. He added amiable notes to the work to the effect that one would like to go so far, but the distance was intimidating. In fact, he omitted altogether from his translation the very important phrase that “light would be thrown on the origin of man.” It would be a terrible affair, he thought, if the discussion were at once turned on this. Man himself owing his origin neither to God nor the finger of God, but to natural selection in the ordinary course of natural laws! It was not to be thought of. Hence the phrase was struck out, as quite too extravagant, in his otherwise admirable work.

Bronn had himself become something of a revolutionary amongst his colleagues by the translation. The rigidly “exact” workers crossed themselves before the Germanised work. Most of the “evolutionists” in the older sense had by no means the bonhomie to speak even of a “possibility” like the patriarch Bronn. From the first Darwin was—Haeckel was the first to experience it—branded with the anathemas of the two opposite schools of science in Germany. On the one hand the rigorous and exact workers declared that his teaching was pure metaphysics, because it sought to prove evolution and contemplated vast ideal connections. On the other hand the Dualist metaphysicians denounced him as an empiric of the worst character, who sought to replace the great ideal elements in the world by a few miserable natural necessities. It is significant to find that Schopenhauer, the brilliant thinker, regarded the Origin of Species as one of the empirical soapsud or barber books produced by exact investigation, which he thoroughly despised from his metaphysical point of view. And there were already (there are more to-day) whole schools of zoology and botany that looked upon Darwin’s theoretical explanations as unscientific “mysticism,” “metaphysics,” and “philosophy in the worst sense of the word.”

Haeckel read the dangerous book at Berlin in May, 1860. “It profoundly moved me,” he writes to me, “at the first reading. But as all the Berlin magnates (with the single exception of Alexander Braun) were against it, I could make no headway in my defence of it. I did not breathe freely until I visited Gegenbaur at Jena (June, 1860); my long conversations with him finally confirmed my conviction of the truth of Darwinism or transformism.”

It was, therefore, in the critical days immediately before or during the negotiations with Gegenbaur which led to his setting up as a private teacher at Jena. The names of Darwin and Jena unite chronologically in Haeckel’s life—two great names that were to bear him into the very depths of his career, and that have their roots in the same hour.

We may ask what it was in the book that “profoundly moved” the young student of the radiolaria. The name of Braun only partly explains the matter, as Braun was an evolutionist of the same type as Bronn. He was amiably disposed to meet it, but did not openly enter on the new path. We must go deeper. We then understand it clearly enough, if we recollect Haeckel’s bent in the last few years.

He had no longer any scruples with regard to religion. The God of tradition had been entirely replaced in him by Goethe’s God, who did not stand outside of, but was one with, nature. “There is nothing within, nothing without: for what is within is without.” There was not a kernel, God, and a shell, Nature. “Nature has neither kernel nor shell: it is both together.”

The years spent in southern Italy had certainly helped to bring out as strongly as possible the contrast between Goethe’s conception and the conventional idea of God as an extramundane Creator. No surroundings are more apt to do this than the Romance peoples of the Mediterranean. In the northern, Protestant countries the ecclesiastical tradition of Deity has always a spiritual element, a kind of vague resolution into moral laws, that in some measure approach natural law, though one made by man. There is no trace of this in Naples and Sicily. The supernatural there is the saint, the madonna; they penetrate unceasingly into the natural reality, in every little detail of life and conduct. The antithesis of the poor cosmic machinery and the ever-present heavenly help and supersession of it is raised to a supreme height in the popular belief. Miracles are not relegated to earlier days and ancient books. They are expected, affirmed, and believed every day. The saint fills the net of the fisherman as he chases the edible cuttle-fishes by torchlight. The saint makes the storm that threatens the boat—makes it suddenly out of nothing. The madonna can arrest in a second the glowing stream of lava that rolls towards the village from Vesuvius, and if hundreds of them unite in ardent prayer and the making of vows, she will be appeased and do it. Every hair on a man’s head is twofold; there is the natural hair and a hair that can at any moment be changed, transformed, annihilated, or created afresh from nothing, by divine power. The man who has lived in this atmosphere of practical Dualism for years must be saturated to his innermost being with a feeling of the absolute contradiction between this conception of God and nature and Goethe’s philosophy. If he is to follow Goethe, this ancient extramundane, ever-interfering Deity must be given up without the least attempt at compromise.

Thus Haeckel’s position was incomparably more radical than Darwin’s from the very first. He no longer believed in a Creator, either in whole or part.

He asked himself, therefore, how he could now explain certain things in nature. He had learned from the great Johannes Müller that species were unchangeable, and it was impossible to conceive the spontaneous generation of the living from the dead. The essence, the predominant element of the living thing was the mysterious, purposive “vital force.” The first of these three ideas of the master’s to be surrendered entirely by him was the vital force. Even in Müller’s lifetime, and in his own laboratory, so to say, his pupil, Du Bois-Reymond, made the first great breach in the doctrine with his famous study of animal electricity, a really pioneer piece of work, especially as regards method, at that time. It was now more than ever probable that there was no more a special vital force besides the simple natural forces than there was a God distinct from nature. The animal or the plant was a wonderful outcome of the same laws that had built the crystal or the globe. The sharp distinction between living and dead matter fell into the waste-basket, where so many other Dualistic tags lay, cut off by the shears of science.

But if one of Müller’s theses was abandoned, another was retained as a real blessing with all the more tenacity by his pupils—the thesis that even the scientific investigator shall always “think”—nay, even “philosophise.” Müller called it “using one’s imagination,” in his desire to emphasise it. Now it was certainly a fair philosophic deduction from Du Bois-Reymond’s discoveries that one ought no longer to be so rigid as regards the possibility of spontaneous generation. If the same natural forces are at work in the organic and the inorganic, the living and the dead, it is no longer inconceivable theoretically that life and inorganic matter only differ in degree, not in kind. The distinction might become so slender—either now, or at least in past times—that an apparent “spontaneous generation” might really take place.

Here again, it is plain, Haeckel had a greater freedom than Darwin. Working gradually from above, Darwin desisted when he came to spontaneous generation, and left room for God. Haeckel came into an open field, believing that there was no eternal Deity and that spontaneous generation itself was by no means a forbidding conception. The problem for him was merely, how he could work upward through the plants and animals of all geological periods until he reached man. He was bound to seek to dispense even here with the historical vital force, and explain everything by the great natural laws of the cosmos.

It was in this frame of mind that he received Darwin’s book. Can it be in the least surprising that it “profoundly moved” him. It opened out to him the whole way, just as he desired it. Müller’s third thesis, the immutability of species, broke down. But what did it matter? It was now possible for the first time to construct a philosophical zoology and botany in Müller’s sense, without any vital force and without God.

At the same time this rapid and impulsive acceptance of Darwin’s theory was not merely a decisive moment in Haeckel’s intellectual development; it was bound to be, even externally, a most important step in his career. The theistic controversy was forced on his attention. It passed out of the province of his inmost life, that had hitherto only been discussed in conversation with intimate friends, into the professional work of his most serious and public occupation—into zoology, into the radiolaria at which he had been working for years.

We must realise clearly what it must have meant at that time for a young zoologist, who wanted to do rigorous professional work and had quickly decided to settle at Jena in order to begin his career as an official teacher, to become “a Darwinian” in conviction and open confession. It might cost him both his official position and his scientific future; and this at the very moment when he had just secured them, or was in a better position to secure them. We have here for the first time the open manifestation of a principle in Haeckel’s life that he had hitherto only used inwardly, in application to himself. The truth must be told, whatever it cost. Shoot me dead, morally, materially, or bodily, as you will: but you will have to shoot the law first.

Darwin’s ominous book had been available in Bronn’s translation for two years. The German professional zoologists, botanists, and geologists almost all regarded it as absolute nonsense. Agassiz, Giebel, Keferstein, and so many others, laughed until they were red in the face, like a riotous first-night public that has made up its mind as to the absurdity of the play from the first act, and torment the author as the cat torments a mouse. Then Haeckel gave to the world his long-prepared Monograph on the Radiolaria (1862), the work with which he endeavours to establish—in fact, must establish—his position as an exact investigator, even amongst the academic scholars of the opposite camp. All goes very smoothly for many pages of the work. A few traces of heresy may be detected about page 100. The passage deals with the relation of organ to individual, in connection with the social species of radiolaria that live in communities. It is a subject that Haeckel took up with great vigour later on, as we shall see. Here it affords him an opportunity to say a word about the general fusion of things in the world of life, in opposition to our rigid divisions in classification. Organ and individual pass into each other without any fixed limit. That, he says, is only a repetition of the relation of the plant to the animal. We cannot establish any fixed limitations between them. What we set up as such are only man’s abstractions. In nature itself we never find these subjective abstract ideas of limitation “incorporated purely, but always fading away in gradual transitions; here, again, the scale of organisation rises gradually from the simplest to the most complex, in a continuous development.” However, these are words that might have been written by Schleiden or Unger or Bronn before Darwin’s time.

Yet there is something in the work that would have been a jet of ice-cold water to the Agassizs and Giebels. This brilliant new “Extraordinary Professor of Zoology and Director of the Zoological Museum at Jena University,” as it says on the title-page, accepts Darwin in a certain unambiguous passage late in the text.

It is necessary to bring to light once more this passage, buried in a work that is not easily accessible, an expensive technical work separated from us by four decades now. It is worth doing so, not only on account of the courage it displayed at the time, but also as a document relating to the great controversy of the nineteenth century. It is found on pages 231 and 232, partly in the text, but for the most part in a note. Immediately after giving the table of classification Haeckel goes on to say: “I cannot leave this general account of the relationship of the various families of the radiolaria without drawing special attention to the numerous transitional forms that most intimately connect the different groups and make it difficult to separate them in classification, to some extent.” It is interesting to note that in spite of our very defective knowledge of the radiolaria it is nevertheless possible to arrange “a fairly continuous chain of related forms.” He would like to draw particular attention to this, because “the great theories that Charles Darwin has lately put forward, in his Origin of Species in the Plant and Animal World by Natural Selection, or The Preservation of the Improved Races in the Struggle for Life, and which have opened out a new epoch for systematic biology, have given such importance to the question of the affinities of organisms and to proofs of continuous concatenation that even the smallest contribution towards the further solution of these problems must be welcome.” He then endeavours in the text, without any more theoretical observations, practically to construct a “genealogical tree of the radiolaria,” the first of a large number of such trees in the future. He takes as the primitive radiolarian a simple trellis-worked globule with centrifugal radiating needles, embodied in the Heliosphæra. “At the same time,” he says, characteristically, “this does not imply in the least that all the radiolaria must have descended from this primitive form; I merely show that, as a matter of fact, all these very varied forms may be derived from such a common fundamental type.” In other words, once more, it is conceivable—a golden word even long afterwards. The first “genealogical tree,” a “table of the related families, sub-families, and genera of the radiolaria,” arranged in order from the higher forms down, and connected with lines and brackets, comes next. The text deals thoroughly with the possibility of descent. This closes the first and general part of the monograph. But there is a long note at this point in the text, where Darwin’s title is cited, that gives us his first appreciation of Darwin in detail. It begins: “I cannot refrain from expressing here the great admiration with which Darwin’s able theory of the origin of species has inspired me. Especially as this epoch-making work has for the most part been unfavourably received by our German professors of science, and seems in some cases to have been entirely misunderstood. Darwin himself desires his theory to be submitted to every possible test, and ‘looks confidently to the young workers who will be prepared to examine both sides of the question impartially. Whoever leans to the view that species are changeable will do a service to science by a conscientious statement of his conviction; only in that way can we get rid of the mountain of prejudice that at present covers the subject.’ I share this view entirely,” Haeckel continues, “and on that account feel that I must express here my belief in the mutability of species and the real genealogical relation of all organisms. Although I hesitate to accept Darwin’s views and hypotheses to the full and to endorse the whole of his argument, I cannot but admire the earnest, scientific attempt made in his work to explain all the phenomena of organic nature on broad and consistent principles and to substitute an intelligible natural law for unintelligible miracles. There may be more error than truth in Darwin’s theory in its present form, as the first attempt to deal with the subject. Undeniably important as are the principles of natural selection, the struggle for life, the relation of organisms to each other, the divergence of characters, and all the other principles employed by Darwin in support of his theory, it is, nevertheless, quite possible that there are just as many and important principles still quite unknown to us that have an equal or even greater influence on the phenomena of organic nature. This is the first great attempt to construct a scientific, physiological theory of the development of organic life and to prove that the physiological laws and the chemical and physical forces that rule in nature to-day must also have been at work in the world of yesterday.” Haeckel then refers to Bronn, the translator of the book. With Bronn he calls Darwin’s theory the fertilised egg from which the truth will gradually develop; the pupa from which the long-sought natural law will emerge. And he concludes: “The chief defect of the Darwinian theory is that it throws no light on the origin of the primitive organism—probably a simple cell—from which all the others have descended. When Darwin assumes a special creative act for this first species, he is not consistent and, I think, not quite sincere. However, apart from these and other defects, Darwin’s theory has the undying merit of bringing sense and reason into the whole subject of the relations of living things. When we remember how every great reform, every important advance, meets with a resistance in proportion to the depth of the prejudices and dogmas it assails, we shall not be surprised that Darwin’s able theory has as yet met with little but hostility instead of its well-merited appreciation and test.” There is yet no question of man and his origin. But what he says is very bold for the time; and before a year is out we shall find him drawing the most dangerous conclusion of all. And it is found, not in a late page and note in a stout technical volume, but in the pitiless glare of the sunlight, in the most prominent position that could then be given to it in German scientific culture.

CHAPTER V
THE SCIENTIFIC CONGRESS OF 1863

In the second decade of the nineteenth century, Oken had inspired the formation of large public gatherings of German naturalists and physicians. Oken was one of the advanced thinkers who felt that all technical science was in the end only preparatory to the great work of educating the people. In his opinion the naturalist, even if he spent his whole life in investigating the filaments of plants or the limbs of insects, was a pioneer of culture. In any case these gatherings were a very good practical move at the time. In a time of terrible reaction on all sides a feeling came at last even to the recluse of science that, besides the technical value of his work, it ought to do something towards lifting his fellows out of the rut they were falling into. They felt that if all ideals were going to be lost, the ultimate aim of special research would perish with them. Oken took up a position of democratic opposition. He was soon joined by Alexander von Humboldt, who, with the same feeling at heart, gave the work a certain polish of scientific and impartial dignity. There are features of his work that amuse us to-day, but those were evil days, and every particle of goodwill had to be appreciated. However, there was a serious difficulty.