by Grant Allen
For the two years from her arrival at Monte Video, the ‘Beagle’ was employed in surveying the eastern coast of South America; and Darwin enjoyed unusual opportunities for studying the geology, the zoology, and the botany of the surrounding districts during all that period. It was a suggestive field indeed for the young naturalist. The curious relationship of the gigantic fossil armour-plated animals to the existing armadillo, of the huge megatherium to the modern sloths, and of the colossal ant-eaters to their degenerate descendants at the present day, formed one of the direct inciting causes to the special study which produced at last the ‘Origin of Species.’ In the Introduction to that immortal work Darwin wrote, some twenty-seven years later, ‘When on board H.M.S. “Beagle” as naturalist, I was much struck with certain facts in the distribution of the organic beings inhabiting South America, and in the geological relations of the present to the past inhabitants of that continent. These facts, as will be seen in the latter chapters of this volume, seemed to throw some light on the origin of species — that mystery of mysteries, as it has been called by one of our greatest philosophers.’ And in the body of the work itself he refers over and over again to numberless observations made by himself during this period of rapid psychological development — observations on the absence of recent geological formations along the lately upheaved South American coast; on the strange extinction of the horse in La Plata; on the affinities of the extinct and recent species; on the effect of minute individual peculiarities in preserving life under special circumstances; and on the influence of insects and blood-sucking bats in determining the existence of the larger naturalised mammals in parts of Brazil and the Argentine Republic. It was the epoch of wide collection of facts, to be afterwards employed in brilliant generalisations: the materials for the ‘Origin of Species’ were being slowly accumulated in the numberless pigeon-holes of the Darwinian memory.
Among the facts thus industriously gathered by Darwin in the two years spent on the South American coast were several curious instincts of the cuckoo-like molothrus, of the owl of the Pampas, and of the American ostrich. A few sentences scattered here and there through this part of the ‘Naturalist’s Journal’ may well be extracted in the present place as showing, better than any mere secondhand description could do, the slow germinating process of the ‘Origin of Species.’ In speaking of the toxodon, that strange extinct South American mammal, the young author remarks acutely that, though in size it equalled the elephant and the megatherium, the structure of its teeth shows it to be closely allied to the ruminants, while several other details link it to the pachyderms, and its aquatic peculiarities of ear and nostril approximate it rather to the manatee and the dugong. ‘How wonderfully,’ he says, ‘are the different orders, at the present time so well separated, blended together in different points of the structure of the toxodon.’ We now know that unspecialised ancestral forms always display this close union of peculiarities afterwards separately developed in distinct species of their later descendants.
Still more pregnant with evolutionism in the bud is the prophetic remark about a certain singular group of South American birds, ‘This small family is one of those which, from its varied relations to other families, although at present offering only difficulties to the systematic naturalist, ultimately may assist in revealing the grand scheme, common to the present and past ages, on which organised beings have been created.’ Of the agouti, once more, that true friend of the desert, Darwin notes that it does not now range as far south as Port St. Julian, though Wood in 1670 found it abundant there; and he asks suggestively, ‘What cause can have altered, in a wide, uninhabited, and rarely visited country, the range of an animal like this?’ Again, when speaking of the analogies between the extinct camel-like macrauchenia and the modern guanaco, as well as of those between the fossil and living species of South American rodents, he says, with even more prophetic insight, ‘This wonderful relationship in the same continent between the dead and the living will, I do not doubt, hereafter throw more light on the appearance of organic beings on our earth, and their disappearance from it, than any other class of facts.’ He was himself destined in another thirty years to prove the truth of his own vaticination.
A yet more remarkable passage in the ‘Journal of the “Beagle,”’ though entered under the account of events observed in the year 1834, must almost certainly have been written somewhat later, and subsequently to Darwin’s first reading of Malthus’s momentous work, ‘The Principle of Population,’ which (as we know from his own pen) formed a cardinal point in the great biologist’s mental development. It runs as follows in the published journal:— ‘We do not steadily bear in mind how profoundly ignorant we are of the conditions of existence of every animal; nor do we always remember that some check is constantly preventing the too rapid increase of every organised being left in a state of nature. The supply of food, on an average, remains constant; yet the tendency in every animal to increase by propagation is geometrical, and its surprising effects have nowhere been more astonishingly shown than in the case of the European animals run wild during the last few centuries in America. Every animal in a state of nature regularly breeds; yet in a species long established any great increase in numbers is obviously impossible, and must be checked by some means.’ Aut Malthus aut Diabolus. And surely here, if anywhere at all, we tremble on the very verge of natural selection.
It would be impossible to follow young Darwin in detail through his journey to Buenos Ayres, and up the Parana to Santa Fé, which occupied the autumn of 1833. In the succeeding year he visited Patagonia and the Falkland Islands, having previously made his first acquaintance with savage life among the naked Fuegians of the extreme southern point of the continent. Some of these interesting natives, taken to England by Captain Fitzroy on a former visit, had accompanied the ‘Beagle’ through all her wanderings, and from them Darwin obtained that close insight into the workings of savage human nature which he afterwards utilised with such conspicuous ability in the ‘Descent of Man.’ Through Magellan’s Straits the party made their way up the coasts of Chili, and Darwin had there an opportunity of investigating the geology and biology of the Cordillera. The year 1835 was chiefly spent in that temperate country and in tropical Peru; and as the autumn went on, the ‘Beagle’ made her way across a belt of the Pacific to the Galapagos archipelago.
Small and unimportant as are those little equatorial islands from the geographical and commercial point of view, they will yet remain for ever classic ground to the biologists of the future from their close connection with the master-problems of the ‘Origin of Species.’ Here more, perhaps, than anywhere else the naturalist of the ‘Beagle’ found himself face to face in real earnest with the ultimate questions of creation or evolution. A group of tiny volcanic islets, never joined to any land, nor even united to one another, yet each possessing its own special zoological features — the Galapagos roused to an extraordinary degree the irresistible questionings of Darwin’s mind. They contain no frogs, and no mammal save a mouse, brought to them, no doubt, by some passing ship. The only insects are beetles, which possess peculiar facilities for being transported in the egg or grub across salt water upon floating logs. There are two kinds of snake, one tortoise, and four lizards; but, in striking contrast to this extreme poverty of terrestrial forms, there are at least fifty-five distinct species of native birds. A few snails complete the list. Now most of these animals, though closely resembling the fauna of Ecuador, the nearest mainland, are specifically distinct; they have varied (as we now know) from their continental types owing to natural selection under the new circumstances in which they have been placed. But Darwin had not yet evolved that potent key to the great riddle of organic existence. He saw the problem, but not its solution. ‘Most of the organic productions,’ he says plainly, ‘are aboriginal creations, found nowhere else; there is even a difference between the inhabitants of the different islands: yet all show a marked relationship with those of America, though separated from that conti
nent by an open space of ocean, between 500 and 600 miles in width.... Considering the small size of these islands, we feel the more astonished at the number of their aboriginal beings, and at their confined range. Seeing every height crowned with its crater, and the boundaries of most of the lava-streams still distinct, we are led to believe that within a period geologically recent the unbroken sea was here spread out. Hence, both in space and time we seem to be brought somewhat nearer to that great fact — that mystery of mysteries — the first appearance of new beings on this earth.’ Among the most singular of these zoological facts may be mentioned the existence in the Galapagos archipelago of a genus of gigantic and ugly lizard, the amblyrhyncus, unknown elsewhere, but here assuming the forms of two species, the one marine and the other terrestrial. In minuter points, the differences of fauna and flora between the various islands are simply astounding, so as to compel the idea that each form must necessarily have been developed not merely for the group, but for the special island which it actually inhabits. No wonder that Darwin should say in conclusion, ‘One is astonished at the amount of creative force, if such an expression may be used, displayed on these small, barren, and rocky islands; and still more so at its diverse, yet analogous, action on points so near each other.’ Here again, in real earnest, the young observer trembles visibly on the very verge of natural selection. In the ‘Origin of Species’ he makes full use, more than once, of the remarkable facts he observed with so much interest in these tiny isolated oceanic specks of the American galaxy.
From the Galapagos the ‘Beagle’ steered a straight course for Tahiti, and Darwin then beheld with his own eyes the exquisite beauty of the Polynesian Islands. Thence they sailed for New Zealand, the most truly insular large mass of land in the whole world, supplied accordingly with a fauna and flora of most surprising meagreness and poverty of species. In the woods, our observer noted very few birds, and he remarks with astonishment that so big an island — as large as Great Britain — should not possess a single living indigenous mammal, save a solitary rat of doubtful origin. Australia and Tasmania, with their antiquated and stranded marsupial inhabitants, almost completed the round trip. Keeling Island next afforded a basis for the future famous observations upon coral reefs; and thence by Mauritius, St. Helena, Ascension, Bahia, Pernambuco, and the beautiful Azores, the ‘Beagle’ made her way home by slow stages to England, which she reached in safety on October the 2nd, 1836. What an ideal education for the future reconstructor of biological science! He had now all his problems cut and dried, ready to his hand, and he had nothing important left to do — except to sit down quietly in his study, and proceed to solve them. Observation and collection had given him one half the subject-matter of the ‘Origin of Species;’ reflection and Malthus were to give him the other half. Never had great mind a nobler chance; never, again, had noble chance a great mind better adapted by nature and heredity to make the most of it. The man was not wanting to the opportunity, nor was the opportunity wanting to the man. Organism and environment fell together into perfect harmony; and so, by a lucky combination of circumstances, the secret of the ages was finally wrung from not unwilling nature by the far-seeing and industrious volunteer naturalist of the ‘Beagle’ expedition.
It would be giving a very false idea of the interests which stirred Charles Darwin’s mind during his long five years’ voyage, however, if we were to dwell exclusively upon the biological side of his numerous observations on that memorable cruise. Ethnology, geology, oceanic phenomena, the height of the snow-line, the climate of the Antarctic islands, the formation of icebergs, the transport of boulders, the habits and manners engendered by slavery, all almost equally aroused in their own way the young naturalist’s vivid interest. Nowhere do we get the faintest trace of narrow specialism; nowhere are we cramped within the restricted horizon of the mere vulgar beetle-hunter and butterfly-catcher. The biologist of the ‘Beagle’ had taken the whole world of science for his special province. Darwin’s mind with all its vastness was not, indeed, profoundly analytical. The task of working out the psychological and metaphysical aspects of evolution fell rather to the great organising and systematising intellect of Herbert Spencer. But within the realm of material fact, and of the widest possible inferences based upon such fact, Darwin’s keen and comprehensive spirit ranged freely over the whole illimitable field of nature. ‘No one,’ says Buckle with unwonted felicity, ‘can have a firm grasp of any science if, by confining himself to it, he shuts out the light of analogy. He may, no doubt, work at the details of his subject; he may be useful in adding to its facts; he will never be able to enlarge its philosophy. For the philosophy of every department depends on its connection with other departments, and must therefore be sought at their points of contact. It must be looked for in the place where they touch and coalesce: it lies, not in the centre of each science, but on the confines and margin.’ This profound truth Darwin fully and instinctively realised. It was the all-embracing catholicity of his manifold interests that raised him into the greatest pure biologist of all time, and that enabled him to co-ordinate with such splendid results the raw data of so many distinct and separate sciences. And even as early as the days of the cruise in the ‘Beagle,’ that innate catholicity had already asserted itself in full vigour. Now it is a party of Gauchos throwing the bola that engages for the moment his eager attention; and now again it is a group of shivering Fuegians, standing naked with their long hair streaming in the wind on a snowy promontory of their barren coast. Here he examines the tubular lightning-holes melted in the solid rock of Maldonado by the electric energy; and there he observes the moving boulder-streams that course like torrents down the rugged corries of the Falkland Islands. At one time he works upon the unstudied geology of the South American Pampas; at another, he inspects the now classical lagoon and narrow fringing reef of the Keeling archipelago. Everywhere he sees whatever of most noteworthy in animate or inanimate nature is there to be seen; and everywhere he draws from it innumerable lessons, to be applied hereafter to the special field of study upon which his intense and active energies were finally concentrated. It is not too much to say, indeed, that it was the voyage of the ‘Beagle’ which gave us in the last resort the ‘Origin of Species’ and its great fellow the ‘Descent of Man.’
The full narrative was first given to the world in 1839, some three years after Darwin’s return to England, so that much of it evidently represents the results of his maturer thinking and reading on the facts collected during his journey round the world.
CHAPTER V.
THE PERIOD OF INCUBATION.
When Charles Darwin landed in England on his return from the voyage of the ‘Beagle’ he was nearly twenty-eight. When he published the first edition of the ‘Origin of Species’ he was over fifty. The intermediate years, though much occupied by many minor works of deep specialist scientific importance, were still mainly devoted to collecting material for the one crowning effort of his life, the chief monument of his great co-ordinating and commanding intellect — the settlement of the question of organic evolution.
‘There is one thing,’ says Professor Fiske, ‘which a man of original scientific or philosophical genius in a rightly ordered world should never be called upon to do. He should never be called upon to earn a living; for that is a wretched waste of energy, in which the highest intellectual power is sure to suffer serious detriment, and runs the risk of being frittered away into hopeless ruin.’ From this unhappy necessity Charles Darwin, like his predecessor Lyell, was luckily free. He settled down early in a home of his own, and worked away at his own occupations, with no sordid need for earning the day’s bread, but with perfect leisure to carry out the great destiny for which the chances of the universe had singled him out. His subsequent history is the history of his wonderful and unique contributions to natural science.
The first thing to be done, of course, was the arrangement and classification of the natural history spoils gathered during the cruise, and the preparation of his own journ
al of the voyage for publication. The strict scientific results of the trip were described in the ‘Zoology of the Voyage of the “Beagle,”’ the different parts of which were undertaken by rising men of science of the highest distinction, under Charles Darwin’s own editorship. Sir Richard Owen took in hand the fossil mammals; Waterhouse arranged their living allies; Gould discussed the birds, Jenyns the fish, and Bell the amphibians and reptiles. In this vast co-operative publication Darwin thus obtained the assistance of many among the most competent specialists in the England of his day, and learned to understand his own collections by the light thrown upon them from the focussed lamps of the most minute technical learning. As for the journal, it was originally published with the general account of the cruise by Captain Fitzroy in 1839, but was afterwards set forth in a separate form under the title of ‘A Naturalist’s Voyage Round the World.’
But while Darwin was thus engaged in arranging and classifying the animals and plants he had brought home with him, the germs of those inquiring ideas about the origin of species which we have already observed in his account of the voyage were quickening into fresh life within him. As he ruminated at his leisure over the results of his accumulations, he was beginning to work upon the great problem with the definite and conscious resolution of solving it. ‘On my return home, it occurred to me,’ he says, ‘in 1837, that something might perhaps be made out on this question by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it. After five years’ work, I allowed myself to speculate on the subject, and drew up some short notes; these I enlarged in 1844 into a sketch of the conclusions that then seemed to me probable; from that period to the present day I have steadily pursued the same object. I hope that I may be excused for entering on these personal details, as I give them to show that I have not been hasty in coming to a decision.’
