(1807-1873)
t first, when a mere boy, twelve years of age," writes the great Swiss naturalist, "I did what most beginners do. I picked up whatever I could lay my hands on, and tried, by such books and authorities as I had at my command, to find the names of these objects. My highest ambition at that time, was to be able to designate the plants and animals of my native country correctly by a Latin name, and to extend gradually a similar knowledge in its application to the productions of other countries. This seemed to me, in those days, the legitimate aim and proper work of a naturalist. I still possess manuscript volumes in which I entered the names of all the animals and plants with which I became acquainted, and I well remember that I then ardently hoped to acquire the same superficial familiarity with the whole creation. I did not then know how much more important it is to the naturalist to understand the structure of a few animals than to command the whole field of scientific nomenclature. Since I have become a teacher, and have watched the progress of students, I have seen that they all begin in the same way. But how many have grown old in the pursuit, without ever rising to any higher conception of the study of nature, spending their life in the determination of species, and in extending scientific terminology! Long before I went to the university, and before I began to study natural history under the guidance of men who were masters in the science during the early part of this century, I perceived that though nomenclature and classification, as then understood, formed an important part of the study, being, in fact, its technical language, the study of living beings in their natural element was of infinitely greater value. At that age--namely, about fifteen--I spent most of the time I could spare from classical and mathematical studies in hunting the neighboring woods and meadows for birds, insects, and land and fresh-water shells. My room became a little menagerie, while the stone basin under the fountain in our yard was my reservoir for all the fishes I could catch. Indeed, collecting, fishing, and raising caterpillars, from which I reared fresh, beautiful butterflies, were then my chief pastimes. What I know of the habits of the fresh-water fishes of Central Europe I mostly learned at that time; and I may add, that when afterward I obtained access to a large library and could consult the works of Bloch and Lacépède, the only extensive works on fishes then in existence. I wondered that they contained so little about their habits, natural attitudes, and mode of action, with which I was so familiar."
It is this way of looking at things that gives to Agassiz's writings their literary and popular interest. He was born in Mortier, Canton Fribourg, May 28th, 1807, the son of a clergyman, who sent his gifted son to the Universities of Zürich, Heidelberg, and Munich, where he acquired reputation for his brilliant powers, and entered into the enthusiastic, intellectual, and merry student-life, taking his place in the formal duels, and becoming known as a champion fencer. Agassiz was an influence in every centre that he touched; and in Munich, his room and his laboratory, thick with clouds of smoke from the long-stemmed German pipes, was a gathering-place for the young scientific aspirants, who affectionately called it "The Little Academy." At the age of twenty-two, he had published his 'Fishes of Brazil,' a folio that brought him into immediate recognition. Cuvier, the greatest ichthyologist of his time, to whom the first volume was dedicated, received him as a pupil, and gave to him all the material that he had been collecting during fifteen years for a contemplated work on Fossil Fishes. In Paris Agassiz also won the friendship of Humboldt, who, learning that he stood in need of money, presented him with so generous a sum as to enable the ambitious young naturalist to work with a free and buoyant spirit.
His practical career began in 1832, when he was installed at Neufchâtel, from which point he easily studied the Alps. Two years later, after the 'Poissons fossiles' (Fossil Fishes) appeared, he visited England to lecture. Then returning to his picturesque home, he applied himself to original investigation, and through his lectures and publications won honors and degrees. His daring opinions, however, sometimes provoked ardent discussion and angry comment.
Agassiz's passion for investigation frequently led him into dangers that imperiled both life and limb. In the summer of 1841, for example, he was lowered into a deep crevasse bristling with huge stalactites of ice, to reach the heart of a glacier moving at the rate of forty feet a day. While he was observing the blue bands on the glittering ice, he suddenly touched a well of water, and only after great difficulty made his companions understand his signal for rescue. These Alpine experiences are well described by Mrs. Elizabeth Gary Agassiz, and also by Edouard Desors in his 'Séjours dans les Glaciers' (Sojourn among the Glaciers: Neufchâtel, 1844). Interesting particulars of these glacial studies ('Études des Glaciers') were soon issued, and Agassiz received many gifts from lovers of science, among whom was numbered the King of Prussia. His zoölogical and geological investigations were continued, and important works on 'Fossil Mollusks,' 'Tertiary Shells,' and 'Living and Fossil Echinoderms' date from this period.
He had long desired to visit America, when he realized this wish in 1846 by an arrangement with the Lowell Institute of Boston, where he gave a series of lectures, afterwards repeated in various cities. So attractive did he find the fauna and flora of America, and so vast a field did he perceive here for his individual studies and instruction, that he returned the following year. In 1848 the Prussian government, which had borne the expenses of his scientific mission,--a cruise along our Atlantic coast to study its marine life,--released him from further obligation that he might accept the chair of geology in the Lawrence Scientific School of Harvard University. His cruises, his explorations, and his methods, combined with his attractive personality, gave him unique power as a teacher; and many of his biographers think that of all his gifts, the ability to instruct was the most conspicuous. He needed no text-books, for he went directly to Nature, and did not believe in those technical, dry-as-dust terms which lead to nothing and which are swept away by the next generation. Many noted American men of science remember the awakening influence of his laboratories in Charleston and Cambridge, his museum at Harvard, and his summer school at Penikese Island in Buzzard's Bay, Massachusetts, where natural history was studied under ideal conditions. It was here that he said to his class:--"A laboratory of natural history is a sanctuary where nothing profane should be tolerated." Whittier has left a poem called "The Prayer of Agassiz," describing
"The isle of Penikese
Ranged about by sapphire seas."
Just as he was realizing two of his ambitions, the establishment of a great museum and a practical school of zoölogy, he died, December 14th, 1873, at his home in Cambridge, and was buried at Mount Auburn beneath pine-trees sent from Switzerland, while a bowlder from the glacier of the Aar was selected to mark his resting-place.
Agassiz was greatly beloved by his pupils and associates, and was identified with the brilliant group--Emerson, Longfellow, Holmes, and Lowell,--each of whom has written of him. Lowell considered his 'Elegy on Agassiz,' written in Florence in 1874, among his best verses; Longfellow wrote a poem for 'The Fiftieth Birthday of Agassiz,' and Holmes 'A Farewell to Agassiz' on his departure for the Andes, whose affectionate and humorous strain thus closes:--
"Till their glorious raid is o'er,
And they touch our ransomed shore!
Then the welcome of a nation,
With its shout of exultation,
Shall awake the dumb creation,
And the shapes of buried aeons
Join the living creatures' paeans,
While the mighty megalosaurus
Leads the palaeozoic chorus,--
God bless the great Professor,
And the land its proud possessor,--
Bless them now and evermore!"
Numerous biographies and monographs of Agassiz exist in many languages, a complete list of which is given in the last published 'Life of Agassiz,' by Jules Marcou (New York and London, 1896), and also in the 'Life of Agassiz,' by Charles F. Holder (New York, 1893). Complete lists of Agassiz's works are also given in these biographies, and these titles show how versatile was his taste and how deep and wide his research. His principal contributions to science are in French and Latin, but his most popular books appeared in English. These include 'The Structure of Animal Life,' 'Methods of Study,' 'Geological Sketches,' and 'Journey in Brazil,' the latter written with Mrs. Agassiz. His 'Contributions to the Natural History of the United States,' planned to be in ten large books, only reached four volumes.
In his 'Researches concerning Fossil Fishes,' Agassiz expressed the views that made him a lifelong opponent of the Darwinian theories, although he was a warm friend of Darwin. Considering the demands upon his time as teacher, lecturer, and investigator, the excellence not less than the amount of the great naturalist's work is remarkable, and won such admiration that he was made a member of nearly every scientific society in the world. One of his favorite pastimes was deep-sea dredging, which embraced the excitement of finding strange specimens and studying their singular habits.
Of his love and gift for instructing, Mrs. Agassiz says in her 'Life' (Boston, 1885):--
"Teaching was a passion with him, and his power over his pupils might be measured by his own enthusiasm. He was, intellectually as well as socially, a democrat in the best sense. He delighted to scatter broadcast the highest results of thought and research, and to adapt them even to the youngest and most uninformed minds. In his later American travels he would talk of glacial phenomena to the driver of a country stage-coach among the mountains, or to some workman splitting rock at the roadside, with as much earnestness as if he had been discussing problems with a brother geologist; he would take the common fisherman into his scientific confidence, telling him the intimate secrets of fish-culture or fish-embryology, till the man in his turn grew enthusiastic and began to pour out information from the stores of his own rough and untaught habits of observation. Agassiz's general faith in the susceptibility of the popular intelligence, however untaught, to the highest truths of nature, was contagious, and he created or developed that in which he believed."
The following citations exhibit his powers of observation, and that happy method of stating scientific facts which interests the specialist and general reader alike.
THE SILURIAN BEACH
From 'Geological Sketches'
With what interest do we look upon any relic of early human history! The monument that tells of a civilization whose hieroglyphic records we cannot even decipher, the slightest trace of a nation that vanished and left no sign of its life except the rough tools and utensils buried in the old site of its towns or villages, arouses our imagination and excites our curiosity. Men gaze with awe at the inscription on an ancient Egyptian or Assyrian stone; they hold with reverential touch the yellow parchment-roll whose dim, defaced characters record the meagre learning of a buried nationality; and the announcement that for centuries the tropical forests of Central America have hidden within their tangled growth the ruined homes and temples of a past race, stirs the civilized world with a strange, deep wonder.
To me it seems, that to look on the first land that was ever lifted above the wasted waters, to follow the shore where the earliest animals and plants were created when the thought of God first expressed itself in organic forms, to hold in one's hand a bit of stone from an old sea-beach, hardened into rock thousands of centuries ago, and studded with the beings that once crept upon its surface or were stranded there by some retreating wave, is even of deeper interest to men than the relics of their own race, for these things tell more directly of the thoughts and creative acts of God.
The statement that different sets of animals and plants have characterized the successive epochs is often understood as indicating a difference of another kind than that which distinguishes animals now living in different parts of the world. This is a mistake. They are so-called representative types all over the globe, united to each other by structural relations and separated by specific differences of the same kind as those that unite and separate animals of different geological periods. Take, for instance, mud-flats or sandy shores in the same latitudes of Europe and America: we find living on each, animals of the same structural character and of the same general appearance, but with certain specific differences, as of color, size, external appendages, etc. They represent each other on the two continents. The American wolves, foxes, bears, rabbits, are not the same as the European. but those of one continent are as true to their respective types as those of the other; under a somewhat different aspect they represent the same groups of animals. In certain latitudes, or under conditions of nearer proximity, these differences may be less marked. It is well known that there is a great monotony of type, not only among animals and plants but in the human races also, throughout the Arctic regions; and some animals characteristic of the high North reappear under such identical forms in the neighborhood of the snow-fields in lofty mountains, that to trace the difference between the ptarmigans, rabbits, and other gnawing animals of the Alps, for instance, and those of the Arctics, is among the most difficult problems of modern science.
And so is it also with the animated world of past ages: in similar deposits of sand, mud, or lime, in adjoining regions of the same geological age, identical remains of animals and plants may be found; while at greater distances, but under similar circumstances, representative species may occur. In very remote regions, however, whether the circumstances be similar or dissimilar, the general aspect of the organic world differs greatly, remoteness in space being thus in some measure an indication of the degree of affinity between different faunae. In deposits of different geological periods immediately following each other, we sometimes find remains of animals and plants so closely allied to those of earlier or later periods that at first sight the specific differences are hardly discernible. The difficulty of solving these questions, and of appreciating correctly the differences and similarities between such closely allied organisms, explains the antagonistic views of many naturalists respecting the range of existence of animals, during longer or shorter geological periods; and the superficial way in which discussions concerning the transition of species are carried on, is mainly owing to an ignorance of the conditions above alluded to. My own personal observation and experience in these matters have led me to the conviction that every geological period has had its own representatives, and that no single species has been repeated in successive ages.
The laws regulating the geographical distribution of animals, and their combination into distinct zoölogical provinces called faunae, with definite limits, are very imperfectly understood as yet; but so closely are all things linked together from the beginning till to-day, that I am convinced we shall never find the clew to their meaning till we carry on our investigations in the past and the present simultaneously. The same principle according to which animal and vegetable life is distributed over the surface of the earth now, prevailed in the earliest geological periods. The geological deposits of all times have had their characteristic faunae under various zones, their zoölogical provinces presenting special combinations of animal and vegetable life over certain regions, and their representative types reproducing in different countries, but under similar latitudes, the same groups with specific differences.
Of course, the nearer we approach the beginning of organic life, the less marked do we find the differences to be; and for a very obvious reason. The inequalities of the earth's surface, her mountain-barriers protecting whole continents from the Arctic winds, her open plains exposing others to the full force of the polar blasts, her snug valleys and her lofty heights, her tablelands and rolling prairies, her river-systems and her dry deserts, her cold ocean-currents pouring down from the high North on some of her shores, while warm ones from tropical seas carry their softer influence to others,--in short, all the contrasts in the external configuration of the globe, with the physical conditions attendant upon them, are naturally accompanied by a corresponding variety in animal and vegetable life.
But in the Silurian age, when there were no elevations higher than the Canadian hills, when water covered the face of the earth with the exception of a few isolated portions lifted above the almost universal ocean, how monotonous must have been the conditions of life! And what should we expect to find on those first shores? If we are walking on a sea-beach to-day, we do not look for animals that haunt the forests or roam over the open plains, or for those that live in sheltered valleys or in inland regions or on mountain-heights. We look for Shells, for Mussels and Barnacles, for Crabs, for Shrimps, for Marine Worms, for Star-Fishes and Sea-Urchins, and we may find here and there a fish stranded on the sand or strangled in the sea-weed. Let us remember, then, that in the Silurian period the world, so far as it was raised above the ocean, was a beach; and let us seek there for such creatures as God has made to live on seashores, and not belittle the Creative work, or say that He first scattered the seeds of life in meagre or stinted measure, because we do not find air-breathing animals when there was no fitting atmosphere to feed their lungs, insects with no terrestrial plants to live upon, reptiles without marshes, birds without trees, cattle without grass,--all things, in short, without the essential conditions for their existence....
I have spoken of the Silurian beach as if there were but one, not only because I wished to limit my sketch, and to attempt at least to give it the vividness of a special locality, but also because a single such shore will give us as good an idea of the characteristic fauna of the time as if we drew our material from a wider range. There are, however, a great number of parallel ridges belonging to the Silurian and Devonian periods, running from east to west, not only through the State of New York, but far beyond, through the States of Michigan and Wisconsin into Minnesota; one may follow nine or ten such successive shores in unbroken lines, from the neighborhood of Lake Champlain to the Far West. They have all the irregularities of modern seashores, running up to form little bays here, and jutting out in promontories there....
Although the early geological periods are more legible in North America, because they are exposed over such extensive tracts of land, yet they have been studied in many other parts of the globe. In Norway, in Germany, in France, in Russia, in Siberia, in Kamchatka, in parts of South America,--in short, wherever the civilization of the white race has extended, Silurian deposits have been observed, and everywhere they bear the same testimony to a profuse and varied creation. The earth was teeming then with life as now; and in whatever corner of its surface the geologist finds the old strata, they hold a dead fauna as numerous as that which lives and moves above it. Nor do we find that there was any gradual increase or decrease of any organic forms at the beginning and close of the successive periods. On the contrary, the opening scenes of every chapter in the world's history have been crowded with life, and its last leaves as full and varied as its first.
VOICES
From 'Methods of Study in Natural History'
There is a chapter in the Natural History of animals that has hardly been touched upon as yet, and that will be especially interesting with reference to families. The voices of animals have a family character not to be mistaken. All the Canidae bark and howl!--the fox, the wolf, the dog, have the same kind of utterance, though on a somewhat different pitch. All the bears growl, from the white bear of the Arctic snows to the small black bear of the Andes. All the cats meow, from our quiet fireside companion to the lions and tigers and panthers of the forests and jungle. This last may seem a strange assertion; but to any one who has listened critically to their sounds and analyzed their voices, the roar of the lion is but a gigantic meow, bearing about the same proportion to that of a cat as its stately and majestic form does to the smaller, softer, more peaceful aspect of the cat. Yet notwithstanding the difference in their size, who can look at the lion, whether in his more sleepy mood, as he lies curled up in the corner of his cage, or in his fiercer moments of hunger or of rage, without being reminded of a cat? And this is not merely the resemblance of one carnivorous animal to another; for no one was ever reminded of a dog or wolf by a lion.
Again, all the horses and donkeys neigh; for the bray of a donkey is only a harsher neigh, pitched on a different key, it is true, but a sound of the same character--as the donkey himself is but a clumsy and dwarfish horse. All the cows low, from the buffalo roaming the prairie, the musk-ox of the Arctic ice-fields, or the yak of Asia, to the cattle feeding in our pastures.
Among the birds, this similarity of voice in families is still more marked. We need only recall the harsh and noisy parrots, so similar in their peculiar utterance. Or, take as an example the web-footed family: Do not all the geese and the innumerable host of ducks quack? Does not every member of the crow family caw, whether it be the jackdaw, the jay, or the magpie, the rook in some green rookery of the Old World, or the crow of our woods, with its long, melancholy caw that seems to make the silence and solitude deeper? Compare all the sweet warblers of the songster family--the nightingales, the thrushes, the mocking-birds, the robins; they differ in the greater or less perfection of their note, but the same kind of voice runs through the whole group.
These affinities of the vocal systems among the animals form a subject well worthy of the deepest study, not only as another character by which to classify the animal kingdom correctly, but as bearing indirectly also on the question of the origin of animals. Can we suppose that characteristics like these have been communicated from one animal to another? When we find that all the members of one zoölogical family, however widely scattered over the surface of the earth, inhabiting different continents and even different hemispheres, speak with one voice, must we not believe that they have originated in the places where they now occur, with all their distinctive peculiarities? Who taught the American thrush to sing like his European relative? He surely did not learn it from his cousin over the waters. Those who would have us believe that all animals originated from common centres and single pairs, and have been thence distributed over the world, will find it difficult to explain the tenacity of such characters, and their recurrence and repetition under circumstances that seem to preclude the possibility of any communication, on any other supposition than that of their creation in the different regions where they are now found. We have much yet to learn, from investigations of this kind, with reference not only to families among animals, but to nationalities among men also....
The similarity of motion in families is another subject well worth the consideration of the naturalist: the soaring of the birds of prey,--the heavy flapping of the wings in the gallinaceous birds,--the floating of the swallows, with their short cuts and angular turns,--the hopping of the sparrows,--the deliberate walk of the hens and the strut of the cocks,--the waddle of the ducks and geese,--the slow, heavy creeping of the land-turtle,--the graceful flight of the sea-turtle under the water,--the leaping and swimming of the frog,--the swift run of the lizard, like a flash of green or red light in the sunshine,--the lateral undulation of the serpent,--the dart of the pickerel,--the leap of the trout,--the rush of the hawk-moth through the air,--the fluttering flight of the butterfly,--the quivering poise of the humming-bird,--the arrow-like shooting of the squid through the water,--the slow crawling of the snail on the land,--the sideway movement of the sand-crab,--the backward walk of the crawfish,--the almost imperceptible gliding of the sea-anemone over the rock,--the graceful, rapid motion of the Pleurobrachia, with its endless change of curve and spiral. In short, every family of animals has its characteristic action and its peculiar voice; and yet so little is this endless variety of rhythm and cadence both of motion and sound in the organic world understood, that we lack words to express one-half its richness and beauty.
FORMATION OF CORAL REEFS
From 'Methods of Study in Natural History'
For a long time it was supposed that the reef-builders inhabited very deep waters; for they were sometimes brought up upon sounding-lines from a depth of many hundreds or even thousands of feet, and it was taken for granted that they must have had their home where they were found: but the facts recently ascertained respecting the subsidence of ocean-bottoms have shown that the foundation of a coral-wall may have sunk far below the place where it was laid. And it is now proved, beyond a doubt, that no reef-building coral can thrive at a depth of more than fifteen fathoms, though corals of other kinds occur far lower, and that the dead reef-corals, sometimes brought to the surface from much greater depths, are only broken fragments of some reef that has subsided with the bottom on which it was growing. But though fifteen fathoms is the maximum depth at which any reef-builder can prosper, there are many which will not sustain even that degree of pressure; and this fact has, as we shall see, an important influence on the structure of the reef.
Imagine now a sloping shore on some tropical coast descending gradually below the surface of the sea. Upon that slope, at a depth of from ten to twelve or fifteen fathoms, and two or three or more miles from the mainland, according to the shelving of the shore, we will suppose that one of those little coral animals, to whom a home in such deep waters is congenial, has established itself. How it happens that such a being, which we know is immovably attached to the ground, and forms the foundation of a solid wall, was ever able to swim freely about in the water till it found a suitable resting-place, I shall explain hereafter, when I say something of the mode of reproduction of these animals. Accept, for the moment, my unsustained assertion, and plant our little coral on this sloping shore, some twelve or fifteen fathoms below the surface of the sea.
The internal structure of such a coral corresponds to that of the sea-anemone. The body is divided by vertical partitions from top to bottom, leaving open chambers between; while in the centre hangs the digestive cavity, connected by an opening in the bottom with all these chambers. At the top is an aperture serving as a mouth, surrounded by a wreath of hollow tentacles, each one of which connects at its base with one of the chambers, so that all parts of the animal communicate freely with each other. But though the structure of the coral is identical in all its parts with the sea-anemone, it nevertheless presents one important difference. The body of the sea-anemone is soft, while that of the coral is hard.
It is well known that all animals and plants have the power of appropriating to themselves and assimilating the materials they need, each selecting from the surrounding elements whatever contributes to its well-being. Now, corals possess in an extraordinary degree, the power of assimilating to themselves the lime contained in the salt water around them; and as soon as our little coral is established on a firm foundation, a lime deposit begins to form in all the walls of its body, so that its base, its partitions, and its outer wall, which in the sea-anemone remain always soft, become perfectly solid in the polyp coral, and form a frame as hard as bone.
It may naturally be asked where the lime comes from in the sea which the corals absorb in such quantities. As far as the living corals are concerned the answer is easy, for an immense deal of lime is brought down to the ocean by rivers that wear away the lime deposits through which they pass. The Mississippi, whose course lies through extensive lime regions, brings down yearly lime enough to supply all the animals living in the Gulf of Mexico. But behind this lies a question, not so easily settled, as to the origin of the extensive deposits of limestone found at the very beginning of life upon earth. This problem brings us to the threshold of astronomy; for the base of limestone is metallic in character, susceptible therefore of fusion, and may have formed a part of the materials of our earth, even in an incandescent state, when the worlds were forming. But though this investigation as to the origin of lime does not belong either to the naturalist or the geologist, its suggestion reminds us that the time has come when all the sciences and their results are so intimately connected that no one can be carried on independently of the others. Since the study of the rocks has revealed a crowded life whose records are hoarded within them, the work of the geologist and the naturalist has become one and the same; and at that border-land where the first crust of the earth was condensed out of the igneous mass of materials which formed its earliest condition, their investigation mingles with that of the astronomer, and we cannot trace the limestone in a little coral without going back to the creation of our solar system, when the worlds that compose it were thrown off from a central mass in a gaseous condition.
When the coral has become in this way permeated with lime, all parts of the body are rigid, with the exception of the upper margin, the stomach, and the tentacles. The tentacles are soft and waving, projected or drawn in at will; they retain their flexible character through life, and decompose when the animal dies. For this reason the dried specimens of corals preserved in museums do not give us the least idea of the living corals, in which every one of the millions of beings composing such a community is crowned by a waving wreath of white or green or rose-colored tentacles.
As soon as the little coral is fairly established and solidly attached to the ground, it begins to bud. This may take place in a variety of ways, dividing at the top or budding from the base or from the sides, till the primitive animal is surrounded by a number of individuals like itself, of which it forms the nucleus, and which now begin to bud in their turn, each one surrounding itself with a numerous progeny, all remaining, however, attached to the parent. Such a community increases till its individuals are numbered by millions, and I have myself counted no less than fourteen millions of individuals in a coral mass of Porites measuring not more than twelve feet in diameter. The so-called coral heads, which make the foundation of a coral wall, and seem by their massive character and regular form especially adapted to give a strong, solid base to the whole structure, are known in our classification as the Astraeans, so named on account of the little [star-shaped] pits crowded upon their surface, each one of which marks the place of a single more or less isolated individual in such a community.
Selections used by permission of Houghton, Mifflin & Company, Publishers.