VI. ERNST HAECKEL AND THE NEW ZOOLOGY
THE DREAM CITY
THE train crept on its tortuous way down the picturesque valley of the little Saale. At last we saw, high above us, on a jutting crag, three quaint old castles, in one of which, as we knew from our Baedeker; Goethe at one time lived. We were entering the region of traditions. Soon we knew we should be passing that famous battle-field on which Napoleon, in 1806, sealed the fate of Germany for a generation. But this spot, as seen from the car window, bore no emblem to distinguish it, and before we were quite sure that we had reached it we had in point of fact passed on, and the train was coming to a stop. "Jena!" called the guard, and the scramble for "luggage" began, leaving us for the moment no place for other thoughts than to make sure that all our various parcels were properly dragged out along with ourselves. For a wonder no Dienstman appeared to give us aid—showing how unexpected is the arrival of any wayfarer at this untoward season—and for a moment one seemed in danger of being reduced to the unheard-of expedient of carrying one's own satchel. But, fortunately, one is rescued from this most un-German predicament by the porter of a waiting hotel omnibus, and so at last we have time to look about us, and to awaken to a realizing sense that we have reached the land of traditions; that we have come to Mecca; that we are in the quondam home of Guericke, Fichte, Goethe, Schiller, Oken, and Gagenbaur; in the present home of Haeckel.
The first glimpse of a mountain beaming down at us from across the way was in admirable conformity with our expectations, but for the rest, the vicinage of the depot presented a most distressing air of modernity. A cluster of new buildings—some of them yet unfinished—stared back at us and the mountain with the most barefaced aspect of cosmopolitanism. Was this, then, Jena, the home of traditions? Or were we entering some Iowa village, where the first settlers still live who but yesterday banished the prairie-dog and the buffalo?
But this disappointment and its ironical promptings were but fleeting. Five minutes' drive and we were in the true Jena with the real flavor of mediaeval-ism about us. Here is the hostelry where Luther met the Swiss students in 1522. There is nothing in that date to suggest our Iowa village, nor in the aspect of the hostelry itself, thank fortune. And there rises the spire of the city church, up the hill yonder, which was aging, as were most of the buildings that still flank it, when Luther made that memorable visit. America was not discovered, let alone Iowa, when these structures were erected. Now, sure enough, we are in the dream city.
A dream city it truly seems, when one comes to wander through its narrow, tortuous streets, between time-stained walls, amid its rustic population. Coming from Berlin, from Dresden, from Leipzig—not to mention America—one feels as if he had stepped suddenly back two or three centuries into the past. There are some evidences of modernity that mar the illusion, to be sure; but the preponderance of the old-time emblems is sufficient to leave the mind in a delightful glow of reminiscences. As a whole, the aspect of the central portion of the village—of the true Jena—cannot greatly have changed since the days when Luther stopped here on his way to Wittenberg; surely not since 1662, when the mighty young Leibnitz, the Aristotle of Germany, came to Jena to study under Weigel, the most famous of German mathematicians of that century. Here and there an old house has been demolished, to be sure; even now you may see the work of destruction going on, as a new street is being cut through a time-honored block close to the old church. But in the main the old thoroughfares run hither and thither, seemingly at random, as of old, disclosing everywhere at their limits a sky-line of picturesque gables, and shut in by walls that often are almost canon-like in narrowness; while the heavy, buttressed doors and the small, high-placed windows speak of a time when every house partook of the nature of the fortress.
The footway of the thoroughfares has no doubt vastly changed, for it is for the most part paved now—badly enough, to be sure, yet, after all, paved as no city was in the good old days when garbage filled the streets and cleanliness was an unknown virtue. The Jena streets of to-day are very modern in their cleanliness; yet a touch of medievalism is retained in that the main work of cleaning is done by women. But, for that matter, it seems to the casual observer as if the bulk of all the work here were performed by the supposedly weaker sex. Certainly woman is here the chief beast of burden. In every direction she may be seen, in rustic garb, struggling cheerily along under the burden of a gigantic basket strapped at her back. You may see the like anywhere else in Germany, to be sure, but not often elsewhere in such preponderant numbers. And scarcely elsewhere does the sight jar so little on one's New-World sensibilities as in the midst of this mediaeval setting. One is even able to watch the old women sawing and splitting wood in the streets here, with no thought of anything but the picturesque-ness of the incident.
If one follows a band of basket-laden women, he will find that their goal is that focal-point of every old-time city, the market-place. There arrived, he will witness a scene common enough in Europe but hardly to be duplicated anywhere in America. Hundreds of venders of meat, fish, vegetables, cloths, and household utensils have their open-air booths scattered all across the wide space, and other hundreds of purchasers are there as well. Quaint garbs and quainter faces are everywhere, and the whole seems quite in keeping with the background of fifteenth-century houses that hedges it in on every side. Could John the Magnanimous, who rises up in bronze in the midst of the assembly, come to life, he would never guess that three and a half centuries have passed since he fell into his last sleep.
This same John the Magnanimous it was who founded the institution which gives Jena its fame and distinguishes it from all the other quaint hypnotic clusters of houses that nestle similarly here and there in other picturesque valleys of the Fatherland—I mean, of course, its world-renowned university. It is but a few minutes' walk from the market-place, past the home where Schiller once lived and through the "street" scarcely more than arms'-breadth wide beyond, to the site of the older buildings of the university. Inornate, prosaic buildings they are, unrelieved even by the dominant note of picturesqueness; rescued, however, from all suggestion of the commonplace by the rugged ruins of the famed "powder-tower" jutting out from the crest of the hill just above, by the spire of the old church which seems to rise from the oldest university building itself, and by the mountain peaks that jut up into view far beyond.
If you would enter one of the old buildings there is naught to hinder. Go into one of the lecture-halls which chances at the moment to be unoccupied, and you will see an array of crude old benches for seats that look as if they might have been placed there at the very inaugural of the institution. The boards that serve for desks, if you scan them closer, you will find scarred all over with the marks of knives, showing how some hundreds of successive classes of listeners have whiled away the weary lecture-hours. Not a square inch can you find of the entire desk surface that is un-scarred. If one would woo a new sensation, he has but to seat himself on one of these puritanical old benches and conjure up in imagination the long series of professors that may have occupied the raised platform in front, recalling the manner of thought and dogma that each laid down as verity. He of the first series appears in the garb of the sixteenth century, with mind just eagerly striving to peer a little way out of the penumbra of the Renaissance. The students who carve the first gashes in the new desks will learn, if perchance they listen in intervals of whittling, that this World on which they live is perhaps not flat, but actually round, like a ball. It is debatable doctrine, to be sure, but we must not forget that Signor Columbus, recently dead, found land off to the west which is probably a part of the Asiatic continent. If the earth be indeed a ball, then the sun and stars whirl clear around it in twenty-four hours, travelling thus at an astonishing speed, for the sphere in which they are fastened is situated hundreds of miles away. The sun must be a really great ball of fire—perhaps a mile even in diameter. The moon, as is plain to see, is nearly as large. The stars, of course, are only sparks, though of great brilliancy. They are fixed in a different sphere from that of the sun. In still other spheres are the moon, and a small set of large stars called planets, of which latter there are four, in order that, with the sun, the moon, and the other stars, there may be made seven orders of heavenly bodies—seven being, of course, the magic number in accordance with which the universe is planned.
This is, in substance, the whole subject of astronomy, as that first professor must have taught it, even were he the wisest man of his time. Of the other sciences, except an elementary mathematics, there was hardly so much as an inkling taught that first class of students. You will find it appalling, as you muse, to reflect upon the amazing mixture of utter ignorance and false knowledge which the learned professor of that day brought to the class-room, and which the "educated" student carried away along with his degree. The one and the other knew Greek, Latin, and Bible history and doctrine. Beyond that their minds were as the minds of babes. Yet no doubt the student who went out from the University of Jena in the year 1550 thought himself upon the pinnacles of learning. So he was in his day and age, but could he come to life to-day, in the full flush of his scholarship, yonder wood-vender, plying her saw out here in front of the university building, would laugh in derision at his simplicity and ignorance. So it seems that, after all, the subjects of John the Magnanimous have changed more than a little during the three hundred and odd years that John himself, done in bronze, has been standing out there in the market-place.
THE CAREER OF A ZOOLOGIST
Had one time for it, there would be real interest in noting the steps by which the mental change in question has been brought about; in particular to note the share which the successive generations of Jena professors have taken in the great upward struggle. But we must not pause for that here. Our real concern, despite the haunting reminiscences, is not with the Jena of the past, but with the Jena of to-day; not with ghosts, but with the living personality who has made the Jena of our generation one of the greatest centres of progress in human thought in all the world. Jena is Jena to-day not so much because Guericke and Fichte and Hegel and Schiller and Oken taught here in the past, as because it has for thirty-eight years been the seat of the labors of Germany's greatest naturalist, one of the most philosophical zoologists of any country or any age, Professor Ernst Haeckel. It is of Professor Haeckel and his work that I chiefly mean to write, and if I have dwelt somewhat upon Jena itself, it is because this quaint, retired village has been the theatre of Haeckel's activities all the mature years of his life, and because the work he has here accomplished could hardly have been done so well elsewhere; some of it, for reasons I shall presently mention, could hardly have been done elsewhere at all—at least in another university.
It was in 1861 that young Dr. Haeckel came first to Jena as a teacher. He had made a tentative effort at the practice of medicine in Berlin, then very gladly had turned from a distasteful pursuit to the field of pure science. His first love, before he took up the study of medicine, had been botany, though pictorial art, then as later, competed with science for his favorable attention. But the influence of his great teacher, Johannes Müller, together with his medical studies, had turned his attention more directly to the animal rather than vegetable life, and when he left medicine it was to turn explicitly to zoology as a life study. Here he believed he should find a wider field than in art, which he loved almost as well, and which, it may be added, he has followed all his life as a dilettante of much more than amateurish skill. Had he so elected, Haeckel might have made his mark in art quite as definitely as he has made it in science. Indeed, even as the case stands, his draughtsman's skill has been more than a mere recreation to him, for without his beautiful drawings, often made and reproduced in color, his classical monographs on various orders of living creatures would have lacked much of their present value.
Moreover, quite aside from these merely technical drawings, Professor Haeckel has made hundreds of paintings purely for recreation and the love of it, illustrating—and that too often with true artistic feeling for both form and color—the various lands to which his zoological quests have carried him, such as Sicily, the Canaries, Egypt, and India. From India alone, after a four-months' visit, Professor Haeckel brought back two hundred fair-sized water-colors, a feat which speaks at once for his love of art and his amazing industry.
I dwell upon this phase of Professor Haeckel's character and temperament from the very outset because I wish it constantly to be borne in mind, in connection with some of the doctrines to be mentioned presently, that here we have to do with no dry-as-dust scientist, cold and soulless, but with a broad, versatile, imaginative mind, one that links the scientific and the artistic temperaments in rarest measure. Charles Darwin, with whose name the name of Haeckel will always be linked, told with regret that in his later years he had become so steeped in scientific facts that he had lost all love for or appreciation of art or music. There has been no such mental warping and atrophy in the mind of Ernst Haeckel. Yet there is probably no man living to-day whose mind contains a larger store of technical scientific facts than his, nor a man who has enriched zoology with a larger number of new data, the result of direct personal observation in field or laboratory.
How large Haeckel's contribution in this last regard has been can be but vaguely appreciated by running over the long list of his important publications, though the list includes more than one hundred titles, unless it is understood that some single titles stand for monographs of gigantic proportions, which have involved years of labor in the production. Thus the text alone of the monograph on the radiolarians, a form of microscopic sea-animalcule (to say nothing of the volume of plates), is a work of three gigantic volumes, weighing, as Professor Haeckel laughingly remarks, some thirty pounds, and representing twelve years of hard labor. This particular monograph, by-the-bye, is written in English (of which, as of several other languages, Professor Haeckel is perfect master), and has a history of more than ordinary interest. It appears that the radiolarians were discovered about a half-century ago by Johannes Müller, who made an especial-study of them, which was uncompleted at the time of his death in 1858. His monograph, describing the fifty species then known, was published posthumously. Haeckel, on whom the mantle of the great teacher was to fall, and who had been Müller's last pupil, took up the work his revered master had left unfinished as his own first great original Arbeit. He went to Messina and was delighted to find the sea there replete with radiolarians, of which he was able to discover one or two new species almost every day, until he had added one hundred and fifty all told to Müller's list, or more than triple the whole number previously known. The description of these one hundred and fifty new radiolarians constituted Haeckel's first great contribution to zoology, and won him his place as teacher at Jena in 1861.
Henceforth Haeckel was, of course, known as the greatest authority on this particular order of creatures. For this reason it was that Professor Murray, the naturalist of the famous expedition which the British government sent around the world in the ship Challenger, asked Haeckel to work up the radiolarian material that had been gathered during that voyage. Murray showed Haeckel a little bottle containing water, with a deposit of seeming clay or mud in the bottom. "That mud," he said, "was dredged up from the bottom of the ocean, and every particle of it is the shell of a radiolarian." "Impossible," said Haeckel. "Yet true," replied Murray, "as the microscope will soon prove to you."
So it did, and Professor Haeckel spent twelve years examining that mud under the microscope, with the result that, before he had done, he had discovered no fewer than four thousand new species of radiolarians, all of which, of course, had to be figured, described, and christened. Think of baptizing four thousand creatures, finding a new, distinct, and appropriate Latin name for each and every one, and that, too, when the creatures themselves are of microscopic size, and the difference between them often so slight that only the expert eye could detect it. Think, too, of the deadly tedium of labor in detecting these differences, in sketching them, and in writing out, to the length of three monster volumes, technical dissertations upon them.
To the untechnical reader that must seem a deadly, a veritably mind-sapping task. And such, indeed, it would prove to the average zoologist. But with the mind of a Haeckel it is far otherwise. To him a radiolarian, or any other creature, is of interest, not so much on its own account as for its associations. He sees it not as an individual but as a link in the scale of organic things, as the bearer of a certain message of world-history. Thus the radiolarians, insignificant creatures though they seem, have really taken an extraordinary share in building up the crust of the earth. The ooze at the bottom of the sea, which finally becomes metamorphosed into chalk or stone, is but the aggregation of the shells of dead radiolarians. In the light of such a rôle the animalcule takes on a new interest.
But even greater is the interest that attaches to every creature in regard to the question of its place in the organic scale of evolution. What are the homologies of this form and that? What its probable ancestry? What gaps does it bridge? What can it tell us of the story of animal creation? These and such like are the questions that have been ceaselessly before Haeckel's mind in all his studies of zoology. Hence the rich fountain of philosophical knowledge that has welled up from what otherwise might have been the most barren of laboratory borings. Thus from a careful investigation of the sponge Haeckel was led to his famous gastrula theory, according to which the pouchlike sponge-animalcule—virtually a stomach without members—is the type of organism on which all high organisms are built, so to speak—that is, out of which all have evolved.
This gastrula theory, now generally accepted, is one of Haeckel's two great fundamental contributions to the evolution philosophy with the history of which his life work is so intimately linked. The other contribution is the theory, even more famous and now equally undisputed, that every individual organism, in its em-bryological development, rehearses in slurred but unmistakable epitome the steps of evolution by which the ancestors of that individual came into racial being. That is to say, every mammal, for example, originating in an egg stage, when it is comparable to a protozoon, passes through successive stages when it is virtually in succession a gastrula, a fish, and an amphibian before it attains the mammalian status, because its direct ancestors were in succession, through the long geological ages, protozoons, gastrulae, fishes, amphibians before the true mammal was evolved. This theory cast a flood of light into many dark places of the Darwinian philosophy. It was propounded in 1866 in Professor Haeckel's great work on morphology, and it has ever since been a guiding principle in his important philosophical studies.
It was through this same work on morphology that Haeckel first came to be universally recognized as the great continental champion of Darwinism—the Huxley of Germany. Like Huxley, Haeckel had at once made the logical application of the Darwinian theory to man himself, and he sought now to trace the exact lineage of the human family as no one had hitherto attempted to fathom it. Utilizing his wide range of zoological and anatomical knowledge, he constructed a hypothetical tree of descent—or, if you prefer, ascent—from the root in a protozoon to the topmost twig or most recent offshoot, man. From that day till this Haeckel's persistent labors have been directed towards the perfection of that genealogical tree.
This work on morphology was much too technical to reach the general public, but in 1868 Haeckel prepared, at the instigation of his friend and confrère Gagenbaur, what was practically a popular abridgment of the technical work, which was published under the title of The Natural History of Creation. This work created a furor at once. It has been translated into a dozen languages, and has passed through nine editions in the original German. Through it the name of Haeckel became almost a household word the world over, and subject for mingled applause and opprobrium—applause from the unprejudiced for its great merit; opprobrium from the bigoted because of the unprecedented candor with which it followed the Darwinian hypothesis to its logical goal.
The same complete candor of expression has marked every stage of the unfolding of Professor Haeckel's philosophical pronouncements. This fact is the more remarkable because Professor Haeckel is, so far as I am aware, the only scientist of our generation who has felt at liberty to announce, absolutely without reserve, the full conclusions to which his philosophy has carried him, when these conclusions ran counter to the prevalent prejudices of his time. Some one has said that the German universities are oases of freedom. The remark is absolutely true of Jena. It is not true, I believe, in anything like the same degree of any other German university, or of any other university in the world. One thing before others that has endeared Jena to Haeckel, and kept him there in the face of repeated flattering calls to other universities, is that full liberty of spirit has been accorded him there, as he knew it would not be accorded elsewhere. "When a man comes into the atmosphere of Jena," says Professor Haeckel, "he perforce begins to think—there is no escape from it. And he is free to let his thoughts carry him whithersoever they honestly may. My beliefs," he added, "are substantially the beliefs of my colleagues in science everywhere, as I know from private conversations; but they, unlike myself, are not free to speak the full truth as they see it. I myself would not be tolerated elsewhere, as I am well aware. Had I desired to remain in Berlin, for example, I must have kept silent. But here in Jena one is free."
And he smiles benignly as he says it. The controversies through which he has passed and the calumnies of which he has been the target have left no scars upon this broad, calm spirit.
HAECKEL AS MAN AND TEACHER
It is indeed a delightful experience to meet Professor Haeckel in the midst of his charming oasis of freedom, his beloved Jena. To reach his laboratory you walk down a narrow lane, past Schiller's house, and the garden where Schiller and Goethe used to sit and where now the new observatory stands. Haeckel's laboratory itself is a simple oblong building of yellowish brick, standing on a jutting point of land high above the street-level. Entering it, your eye is first caught by a set of simple panels in the wall opposite the door bearing six illustrious names: Aristotle, Linne, Lamarck, Cuvier, Müller, Darwin—a Greek, a Swede, two Frenchmen, a German, and an Englishman. Such a list is significant; it tells of the cosmopolitan spirit that here holds sway.
The ground-floor of the building is occupied by a lecture-room and by the zoological collection. The latter is a good working-collection, and purports to be nothing else. Of course it does not for a moment compare with the collections of the museums in any large city of Europe or America, nor indeed is it numerically comparable with many private collections, or collections of lesser colleges in America. Similarly, when one mounts the stairs and enters the laboratory proper, he finds a room of no great dimensions and nowise startling in its appointments. It is admirably lighted, to be sure, and in all respects suitably equipped for its purpose, but it is by no means so large or so luxurious as the average college laboratory of America. Indeed, it is not to be mentioned in the same breath with the laboratories of a score or two of our larger colleges. Yet, with Haeckel here, it is unquestionably the finest laboratory in which to study zoology that exists in the world to-day, or has existed for the last third of a century.
Haeckel himself is domiciled, when not instructing his classes, in a comfortable but plain room across the hall—a room whose windows look out across the valley of the Saale on an exquisite mountain landscape, with the clear-cut mountain that Schiller's lines made famous at its focus. As you enter the room a big, robust man steps quickly forward to grasp your hand. Six feet or more in height, compactly built, without corpulence; erect, vigorous, even athletic; with florid complexion and clear, laughing, light-blue eyes that belie the white hair and whitening beard; the ensemble personifying at once kindliness and virility, simplicity and depth, above all, frank, fearless honesty, without a trace of pose or affectation—such is Ernst Haeckel. There is something about his simple, frank, earnest, sympathetic, yet robust, masculine personality that reminds one instinctively, as does his facial contour also, of Walt Whitman.
A glance about the room shows you at once that it is a place for study, and also that it is the room of the most methodical of students. There are books and papers everywhere, yet not the slightest trace of disorder. Clearly every book and every parcel of papers has a place, and is kept in that place. The owner can at any moment lay his hand upon anything he desires among all these documents. This habit of orderliness has had no small share, I take it, in contributing to Professor Haeckel's success in carrying forward many lines of research at the same time, and carrying all to successful terminations. Then there goes with it, as a natural accompaniment, a methodical habit of working, without which no single man could have put behind him the multifarious accomplishments that stand to Professor Haeckers credit.
Orderliness is not a more pronounced innate gift with Professor Haeckel than is the gift of initial energy to undertake and carry on work which leads to accomplishment—a trait regarding which men, even active men, so widely differ. But Professor Haeckel holds that whatever his normal bent in this direction, it was enormously strengthened in boyhood by the precepts of his mother—from whom, by-the-bye, he chiefly inherits his talents. "My mother," he says, "would never permit me to be idle for a moment. If I stood at a window day-dreaming, she would always urge me to be up and doing. 'Work or play,' she would urge, 'but do not stand idle.' Through this reiterated admonition, physical activity became a life-long habit with me, and work almost a necessity of my being. If I have been able to accomplish my full share of labors, this is the reason. I am never idle, and I scarcely know the meaning of ennui."
This must not be interpreted as meaning, however, that Professor Haeckel takes up a task and works at it all day long unceasingly. That is not the German method of working, and in this regard Professor Haeckel is a thorough German. "When I was a young man," he says, "I at one time, thanks to the persuasions of some English friends, became a convert to the English method of working, and even attempted to introduce it into Germany. But I soon relinquished it, and lapsed back into our German method, which I am convinced will produce better results for the average worker. The essential of this method is the long midday rest, which enables one late in the afternoon to begin what is virtually a new day's-work, and carry it out with vigor and without undue fatigue. Thus I, who am an early riser, begin work at five in summer and six in winter, after the customary light breakfast of coffee and rolls. I do not take a second breakfast at ten or eleven, as many Germans do, but work continuously until one o'clock, when I have dinner. This, with me, as with all Germans, is the hearty meal of the day. After dinner I perhaps take a half-hour's nap; then read the newspaper, or chat with my family for an hour, and perhaps go for a long walk. At about four, like all Germans, I take my cup of coffee, but without cake or other food. Then, at four, having had three full hours of brain-rest and diversion, I am ready to go to work again, and can accomplish four hours more of work without undue fatigue. At eight I have my rather light supper, and after that I attempt no further work, giving the evening to reading, conversation, or other recreation. I do not retire till rather late, as I require only five or six hours' sleep."
Such is the method of labor division that enables not Professor Haeckel only, but a host of other German brain-workers to accomplish enormous labors, yet to thrive on the accomplishment and to carry the ruggedness and health of youth far into the decades that are too often with our own workers given over to decrepitude. Haeckel at sixty-five looks as if he were good for at least a score of years of further effort. And should he fulfil the promise of his present rugged-ness, he will do no more than numbers of his colleagues in German universities have done and are doing. When one runs over the list of octogenarians, and considers at the same time the amount of the individual output of the best German workers, he is led to feel that Professor Haeckel was probably right in giving up the continuous-day method of labor and reverting to the German method.
In addition to the original researches that Professor Haeckel has carried out, to which I have already made some reference, there has, of course, been all along another large item of time-consumption to be charged up to his duties as a teacher. These, to be sure, are somewhat less exacting in the case of a German university professor than they are in corresponding positions in England or America. Thus, outside the hours of teaching, Professor Haeckel has all along been able to find about eight hours a day for personal, original research. When he told Professor Huxley so in the days of their early friendship, Huxley exclaimed: "Then you ought to be the happiest man alive. Why, I can find at most but two hours a day to use for myself."
So much for the difference between German methods of teaching, where the university professor usually confines his contact with the pupils to an hour's lecture each day, and the English system, according to which the lecturer is a teacher in other ways as well. Yet it must be added that in this regard Professor Haeckel is not an orthodox German, for his contact with his students is by no means confined to the lecture-hour. Indeed, if one would see him at his best, he must go, not to the lecture-hall, but to the laboratory proper during the hours when Professor Haeckel personally presides there, and brings knowledge and inspiration to the eager band of young dissectors who gather there. It will perhaps seem strange to the reader to be told that the hours on which this occurs are from nine till one o'clock of a day which is perhaps not devoted to class-room exercises in any other school of Christendom whatever—namely, the Sabbath. It is interesting to reflect what would be the comment on such a procedure in London, for example, where the underground railway trains even must stop running during the hours of morning service. But Jena is not London, and, as Professor Haeckel says, "In Jena one is free. It pleases us to have our Sabbath service in our tabernacle of science."
All questions of time aside, it is a favored body of young men who occupy the benches in the laboratory during Professor Haeckel's unique Sunday-morning service. Each student has before him a microscope and a specimen of the particular animal that is the subject of the morning's lesson. Let us say that the subject this morning is the crawfish. Then in addition to the specimens with which the students are provided, and which each will dissect for himself under the professor's guidance, there are scattered about the room, on the various tables, all manner of specimens of allied creatures, such as crabs, lobsters, and the like. There are dissected specimens also of the crawfish, each preparation showing a different set of organs, exhibited in preserving fluids. Then there are charts hung all about the room illustrating on a magnified scale, by diagram and picture, all phases of the anatomy of the subjects under discussion. The entire atmosphere of the place this morning smacks of the crawfish and his allies.
The session begins with a brief off-hand discussion of the general characteristics and affinities of the group of arthropoda, of which the crawfish is a member. Then, perhaps, the professor calls the students about him and gives a demonstration of the curious phenomena of hypnotism as applied to the crawfish, through which a living specimen, when held for a few moments in a constrained attitude, will pass into a rigid "trance," and remain standing on its head or in any other grotesque position for an indefinite period, until aroused by a blow on the table or other shock. Such are some of the little asides, so to speak, with which the virile teacher enlivens his subject and gives it broad, human interest. Now each student turns to his microscope and his individual dissection, and the professor passes from one investigator to another with comment, suggestion, and criticism; answering questions, propounding anatomical enigmas for solution—enlivening, vivifying, inspiring the entire situation.
As the work proceeds, Professor Haeckel now and again calls the attention of the entire class to some particular phase of the subject just passing under their individual observation, and in the most informal of talks, illustrated on blackboard and chart, clears up any lurking mysteries of the anatomy, or enlivens the subject with an incursion into physiology, embryology, or comparative morphology of the parts under observation. Thus by the close of the session the student has something far more than a mere first-hand knowledge of the anatomy of the crawfish—though that in itself were much. He has an insight also into a half-dozen allied subjects. He has learned to look on the crawfish as a link in a living chain—a creature with physiological, psychological, ontological affinities that give it a human interest not hitherto suspected by the novitiate. And when the entire series of Sunday-morning "services" has been carried through, one order after another of the animal kingdom being similarly made tribute, the favored student has gone far towards the goal of a truly philosophical zoology, as different from the old-time dry-bones anatomy as the living crawfish is different from the dead shell which it casts off in its annual moulting time.
THE NEW ZOOLOGY
What, then, is the essence of this "philosophical zoology" of which Haeckel is the greatest living exponent and teacher and of which his pupils are among the most active promoters? In other words, what is the real status, and the import and meaning, the raison d'être, if you will, of the science of zoology to-day?
To clear the ground for an answer to that question, one must glance backward, say half a century, and note the status of the zoology of that day, that one may see how utterly the point of view has changed since then; what a different thing zoology has become in our generation from what it was, for example, when young Haeckel was a student at Jena back in the fifties. At that time the science of zoology was a conglomeration of facts and observations about living things, grouped about a set of specious and sadly mistaken principles. It was held, following Cuvier, that the beings of the animal kingdom had been created in accordance with five preconceived types: the vertebrate, with a spinal column; the articulate, with jointed body and members, as represented by the familiar crustaceans and insects; the mollusk, of which the oyster and the snail are familiar examples; the radiate, with its axially disposed members, as seen in the starfish; and the low, almost formless protozoon, most of whose representatives are of microscopic size. Each of these so-called classes was supposed to stand utterly isolated from the others, as the embodiment of a distinct and tangible idea. So, too, of the lesser groups or orders within each class, and of the still more subordinate groups, named technically families, genera; and, finally, the individual species. That the grouping of species into these groups was more or less arbitrary was of course to some extent understood, yet it was not questioned by the general run of zoologists that a genus, for example, represented a truly natural group of species that had been created as variations upon one idea or plan, much as an architect might make a variety of houses, no one exactly like any other, yet all conforming to a particular type or genus of architecture—for example, the Gothic or the Romanesque. That each of the groups defined by the classifiers had such status as this was the stock doctrine of zoology, as also that the individual species making up the groups, and hence the groups themselves, maintained their individual identity absolutely unaltered from the moment of their creation, throughout all successive generations, to the end of their racial existence.
Such being the fundamental conception of zoology, it remained only for the investigator to study each individual species with an eye to its affinities with other species, that each might be assigned by a scientific classification to the particular place in the original scheme of creation which it was destined to occupy. Once such affinities had been correctly determined and interpreted for all species, the zoological classification would be complete for all time. A survey of the completed schedule of classification would then show at a glance the details of the preconceived system in accordance with which the members of the animal kingdom were created, and zoology would be a "finished" science.
In the application of this relatively simple scheme, to be sure, no end of difficulties were encountered. Each higher animal is composed of so many members and organs, of such diverse variations, that naturalists could never agree among themselves as to just where a balance of affinities between resemblances and differences should be struck; whether, for example, a given species varied so much from the type species of a genus—say the genus Gothic house—as to belong properly to an independent genus—say Romanesque house; or whether, on the other hand, its divergencies were still so outweighed by its resemblances as to permit of its retention as an aberrant member of genus number one. Perpetual quibbling over these matters was quite the order of the day, no two authorities ever agreeing as to details of classification. The sole point of agreement was that preconceived types were in question—if only the zoologists could ever determine just what these types were. Meantime, the student who supposed classifications to be matters of moment, and who laboriously learned to label the animals and birds of his acquaintance with an authoritative Latin name, was perpetually obliged to unlearn what he had acquired, as a new classifier brought new resources of hair-splitting pursuit of a supposed type or ideal to bear on the subject. Where, for example, our great ornithologists of the early part of the century, such as Wilson and Audubon, had classed all our numerous hawks in a genus falco, later students split the group up into numerous genera—just how many it is impossible to say, as no two authorities agreed on that point. Wilson, could he have come back a generation after his death, would have found himself quite at a loss to converse with his successors about the birds he knew and loved so well, using their technical names—though the birds themselves had not changed.
Notwithstanding all the differences of opinion about matters of detail, however, there was, nevertheless, substantial agreement about the broader outlines of classifications, and it might fairly enough have been hoped that some day, when longer study had led to finer discrimination, the mysteries of all the types of creation would be fathomed. But then, while this hope still seemed far enough from realization, Charles Darwin came forward with his revolutionizing doctrine—and the whole time-honored myth of "types" of creation vanished in thin air. It became clear that the zoologists had been attempting a task utterly Sisyphean. They had sought to establish "natural groups" where groups do not exist in nature. They were eagerly peering after an ideal that had no existence outside their imagination. Their barriers of words could not be made to conform to barriers of nature, because in nature there are no barriers.
What, then, was to be done? Should the whole fabric of classification be abandoned? Clearly not, since there can be no science without classification of facts about labelled groupings, however arbitrary. Classifications then must be retained, perfected; only in future it must be remembered that any classification must be more or less arbitrary, and in a sense false; that it is at best only a verbal convenience, not the embodiment of a final ideal. If, for example, we consider the very "natural" group of birds commonly called hawks, we are quite justified in dividing this group into several genera or minor groups, each composed of several species more like one another than like the members of other groups of species—that is, of other genera. But in so doing we must remember that if we could trace the ancestry of our various species of hawks we should find that in the remote past the differences that now separate the groups had been less and less marked, and originally quite non-existent, all the various species having sprung from a common ancestor. The genera of to-day are cousin-groups, let us say; but the parents of the existing species were of one brood, brothers and sisters. And what applies to the minor groups called genera applies also, going farther into the past, to all larger groups as well, so that in the last analysis, all existing creatures being really the evolved and modified descendants of one primordial type, it may be said that all animate creation is but a single kind. In this broadened view the details of classification ceased to have the importance once ascribed to them, and the quibblings of the classifiers seem amusing rather than serious. Yet the changed point of view left the subject by no means barren of interest. For if the multitudinous creatures of the living world are but diversified twig-lets of a great tree of ascent, spread by branching from a common root, at least it is worth knowing what larger branches each group of twiglets—representing a genus, let us say—has sprung from. In particular, since the topmost twig of the tree is represented by man himself and his nearest relatives, is it of human interest to inquire just what branches and main stems will be come upon in tracing back the lineage of this particular offshoot. This attempt had, perhaps, no vast, vital importance in the utilitarian sense in which these terms are oftenest used, but at least it had human interest. Important or otherwise, it was the task that lay open to zoology, and apparently its only task, so soon as the Darwinian hypothesis had made good its status. The man who first took this task in hand, and who has most persistently and wisely followed it, and hence the man who became the recognized leader in the field of the new zoology, was, as I have already intimated, Professor Haeckel. His hypothetical tree of man's lineage, tracing the ancestry of the human family back to the earliest geological times and the lowest orders of beings, has been familiar now for just a third of a century. It was at first confessedly only a tentative genealogy, with many weak limbs and untraced branches. It was perfected from time to time, as new data came to hand, through studies of paleontology, of embryology, and of comparative anatomy. It will be of interest, then, to inquire just what is its status today and to examine briefly Professor Haeckel's own most recent pronouncement regarding it.
Perhaps it is not worth our while here to go too far down towards the root of the genealogical tree to begin our inquiry. So long as it is admitted that the remote ancestry is grounded in the lowest forms of organisms, it perhaps does not greatly matter to the average reader that there are dark places in the lineage during the period when our ancestor had not yet developed a spinal column—when, in other words, he had not attained the dignity of the lowest fish. Neither, perhaps, need we mourn greatly that the exact branch by which our reptilian or amphibian non-mammalian ancestor became the first and most primitive of mammals is still hidden in unexplored recesses of early strata. The most patrician monarch of to-day would not be greatly disturbed as to just who were his ancestors of the days of the cave-dweller. It is when we come a little nearer home that the question begins to take on its seemingly personal significance. Questions of grandparents and great-grandparents concern the patrician very closely. And so all along, the question that has interested the average casual investigator of the Darwinian theory has been the question as to man's immediate ancestor—the parents and grandparents of our race, so to speak. Hence the linking of the word "monkey" with the phrase "Darwinian theory" in the popular mind; and hence, also, the interpretation of the phrase "missing link" in relation to man's ancestry, as applying only to our ancestor and not to any other of the gaps in the genealogical chain.
What, then, is the present status of Haeckel's genealogical tree regarding man's most direct ancestor? Prom what non-human parent did the human race directly spring? That is a question that has proved itself of lasting, vital human interest. It is a question that long was answered only with an hypothesis, but which Professor Haeckel to-day professes to be able to answer with a decisive and affirmative citation not of theories but of facts. In a word, it is claimed that man's immediate ancestor is now actually upon record, that the much-heralded "missing link" is missing no longer. The principal single document, so to speak, on which this claim is based consists of the now famous skull and thigh-bone which the Dutch surgeon, Dr. Eugene Dubois, discovered in the year 1891 in the tertiary strata of the island of Java. Tertiary strata, it should be explained, had never hitherto yielded any fossils bordering on the human type, but this now famous skeleton was unmistakably akin to the human. The thigh in particular, taken by itself, would have been pronounced by any competent anatomist to be of human origin. Unquestionably the individual who bore it had been accustomed to take an erect attitude in walking. And yet the skull was far inferior in size and shape to that of any existing tribe of man—was, indeed, rather of a simian type, though, on the other hand, of about twice the capacity of any existing ape. In a word, it seemed clear that the creature whose part skeleton had been found by Dr. Dubois was of a type intermediate between the lowest existing man and the highest existing man-apes. It was, in short, the actual prototype of that hypothetical creature which Haeckel, in his genealogical tree, had christened pithecanthropus, the ape-man. As such it was christened Pithecanthropus erectus, the erect ape-man.
Now the discovery of this remarkable form did not make Professor Haeckel any more certain that some such form had existed than he was thirty years before when he christened a hypothetical subject with the title now taken by a tangible claimant. But, after all, there is something very taking about a prophecy fulfilled, and so the appearance of Pithecanthropus erectus created no small sensation in the zoological world. He was hailed by Haeckel and his followers as the veritable "missing link," and as such gained immediate notoriety. But, on the other hand, a reactionary party at once attacked him with the most bitter animadversions, denouncing him as no true ancestor of man with a bitterness that is hard to understand, considering that the origin of man from some lower form has long ceased to be matter of controversy. "Pithecanthropus is at least half an ape," they cried, with the clear implication of "anything but an ape for an ancestor!"
I confess I have always found it hard to understand just why this peculiar aversion should always be held against the unoffending ape tribe. Why it would not be quite as satisfactory to find one's ancestor in an ape as in the alternative lines of, for example, the cow, or the hippopotamus, or the whale, or the dog has always been a mystery. Yet the fact of this prejudice holds. Probably we dislike the ape because of the very patency of his human affinities. The poor relation is objectionable not so much because he is poor as because he is a relation. So, perhaps, it is not the apeness, so to speak, of the ape that is objectionable, but rather the human-ness. In any event, the aversion has been matter of common notoriety ever since the Darwinian theory became fully accepted; it showed itself now with renewed force against poor pithecanthropus. A half-score of objections were launched against him. It is needless to rehearse them now, since they were all met valiantly, and the final verdict saw the new-comer triumphantly ensconced in man's ancestral halls as the oldest sojourner there who has any title to be spoken of as "human." He is only half human, to be sure—a veritable ape-man, as his name implies—but exactly therein lies his altogether unique distinction. He is the embodiment of that "missing link" whose nonappearance had hitherto given so much comfort to the sceptical.
Perhaps some crumbs of comfort may be found by the reactionists in the fact that it is not held by Professor Haeckel, or by any other competent authority, that the link which pithecanthropus supplies welds man directly with any existing man-ape—with gorilla, chimpanzee, or orang. It is held that these highest existing apes are side branches, so to say, of the ancestral tree, who developed, in their several ways, contemporaneously with our direct ancestors, but are not themselves directly of the royal line. The existing ape that has clung closest to the direct ancestral type of our own race, it appears, is the gibbon—a creature far less objectionable in that rôle because of the very paucity of his human characteristics, as revealed to the casual observer. Gibbon-like fossil apes are known, in strata representing a time some millions of years antecedent to the epoch of pithecanthropus even, which are held to be directly of the royal line through which pithecanthropus, and the hypothetical Homo stupidus, and the known Homo neanderthalensis, and, lastly, proud Homo sapiens himself have descended. Thus Professor Haeckel is able to make the affirmation, as he did recently before the International Zoological Congress in Cambridge, that man's line of descent is now clearly traced, from a stage back in the Eocene time when our ancestor was not yet more than half arrived to the ape's estate, down to the time of true human development. "There no longer exists," he says, "a 'missing link.' The phyletic continuity of the primate stem, from the oldest lemurs down to man himself, is an historical fact."
It should, perhaps, be added that the force of this rather startling conclusion rests by no means exclusively upon the finding of pithecanthropus and the other fossils, nor indeed upon any paleontological evidence whatever. These, of course, furnish data of a very tangible and convincing kind; but the evidence in its totality includes also a host of data from the realms of embryology and comparative anatomy—data which, as already suggested, enabled Professor Haeckel to predicate the existence of pithecanthropus long in advance of his actual discovery. Whether the more remote gaps in the chain of man's ancestry will be bridged in a manner similarly in accord with Professor Haeckel's predications, it remains for future discoveries of zoologist and paleontologist to determine. In any event, the recent findings have added an increment of glory to that philosophical zoology of which Professor Haeckel is the greatest living exponent.
This tracing of genealogies is doubtless the most spectacular feature of the new zoology, yet it must be clear that the establishment of lines of evolution is at best merely a preparation for the all-important question, Why have these creatures, man included, evolved at all? That question goes to the heart of the new zoological philosophy. A partial answer was, of course, given by Darwin in his great doctrine of natural selection. But this doctrine, while explaining the preservation of favorable variations, made no attempt to account for the variations themselves. Professor Haeckel's contribution to the subject consisted in the revival of the doctrine of Lamarck, that individual variations, in response to environmental influences, are transmitted to the offspring, and thus furnish the material upon which, applying Darwin's principle, evolution may proceed. This Lamarck-Haeckel doctrine was under a cloud for a recent decade, during the brief passing of the Weismannian myth, but it has now emerged, and stands as the one recognized factor in the origin of those variations whose cumulative preservation through natural selection has resulted in the evolution of organic forms.
But may there not be other factors, as yet unrecognized, that supplement the Lamarckian and Darwinian principles in bringing about this marvellous evolution of beings? That, it would seem, is the most vital question that the philosophical zoology of our generation must hand on to the twentieth century. For today not even Professor Haeckel himself can give it answer.