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DARWIN'S CENTURY -- EVOLUTION AND THE MEN WHO DISCOVERED IT |
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Chapter VI: The Voyage of the Beagle
I. The Age of Giants When Thomas Huxley, young, ambitious and competitive, glanced around him in 1851, he saw two men who impressed him as standing head and shoulders above the rest of the English naturalists. Richard Owen and Edward Forbes, he observed to a friend, were of superior learning, originality, and grasp of mind. Of Darwin, his coming master, he added charitably, almost as an afterthought, that he "might be anything if he had good health." [1] There is an element of humor in this impulsive judgment. Within three years, Forbes was dead and the saturnine and devious Owen lived on to become Huxley's and Darwin's mortal antagonist. "I have no reparation to make," Huxley said in reference to their quarrels, on the occasion of Owen's death in 1892; "if the business were to come over again, I should do as I did." Following which, in the typical Huxley fashion, he aided in promoting a memorial for Owen. "The man did honest work," he said gruffly, "enough to deserve his statue, and that is all that concerns the public." [2] In so speaking, he rang down the curtain on the age of giants. Darwin and Lyell were long gone. Huxley was about to go. On one point only, Huxley was mistaken: he had said, still speaking of Owen, "The thing that strikes me most is how he and I and all the things we fought about belong to antiquity. It is almost impertinent to trouble the modern world with such antiquarian business," a Huxley's deprecation of his role was unwarranted. He was, like his great associate Darwin, already a legend in his own lifetime. The little, brilliant band of men who by their united endeavor had swung world thought into a new channel had taken on something of the quality of myth, like the Knights of the Round Table. As long as Science lasts their story will be remembered. And because great deeds demand great obstacles, their enemies also stand immortal in the light of that legend -- perhaps even a little more formidable than in life. The period of hesitant groping, of the patient piling up of facts had ended in 1859 with the publication of The Origin of Species. The master synthesis had finally been achieved. Yet even here the historian must proceed cautiously. The Origin and its author have a history which runs silently and mysteriously through twenty years of ill health, lone effort, and corroding doubt. The sources of such long continued mental effort are not always easy to discern, and it is unlikely that Darwin himself preserved to the end of his life clear memories of all his multiform activity during the years when he was engaged upon his book. Although we possess a great quantity of his correspondence, owing largely to the fact that he was recognized as a genius in his own lifetime, there are, unfortunately, serious gaps in the letters which he preserved from his circle of colleagues -- Hooker, Lyell, Owen, and others. Some of these missing letters we know to be important from the responses which Darwin made to them, but we can only infer their content, and often not clearly, from Darwin's preserved correspondence. Though Darwin's life is far more elaborately documented than that of many world figures, there are, nevertheless, some annoying gaps in the huge mass of private papers. Even more material has apparently perished among associates whose family lines ended in the Victorian period and whose possessions were destroyed or dissipated long ago. To the extent that it is possible, the student of the Darwinian epoch will want to know with what intellectual furniture or preconceptions Darwin began his task, what led him to undertake it, and, finally, what shape his hypothesis took after it had been subjected to the harsh critical battering of the theologians and his brother scientists. The evolutionary hypothesis known as Darwinism was not conceived in a day and Darwin himself was anything but a fanatical dogmatist. As a consequence, there is a certain amount of give-and-take, hesitations persisting through long periods, and, finally, a retreat toward the Lamarckian position. Darwin, as is apt to be the case with any thinker who has opened up extensive new horizons of thought, was in no position to explore personally all of the ramifications of his own discovery. It is an idea open at the peripheries and still being modified and reviewed, as its originator knew quite well that it would be. Our purpose is merely to examine the way in which the hypothesis was put together. To do so we must return once more to the early part of the nineteenth century among ideas with which we are now reasonably familiar. It is here that the youthful Darwin began the researches with which he was to transform the nineteenth-century world view. We know also that scientific innovators are not born into a vacuum. We shall want to learn, therefore, something of Darwin's family background, his schooling, and the state of scientific thought at the time, in 1831, when young Charles Darwin made his memorable decision to accept the position of naturalist on H.M.S. Beagle for a five-year voyage 'around the world. Most of this story is common knowledge, but there are a few intriguing points of mystery remaining even today. II. The Influence of Erasmus Darwin There were two separate channels by which Charles Darwin was familiarized with the general idea of evolution in his youth. Though the little autobiography which he wrote at the urging of his children in his declining years is not particularly explicit upon such points as this, one such channel can be documented, and the other, though not extensively discussed by Darwin, can scarcely be ignored as an almost certain source of information. One, the more certain channel, lies in the poetry and prose of grandfather Erasmus Darwin, which achieved sufficient world renown as to make it very certain that the ideas of Erasmus would be discussed in family circles. Moreover, the schoolboy who boasted of a fondness for Shakespeare would surely have tried the wares of a poet within the immediate confines of the family. In fact, Darwin himself tells us that he had read his grandfather's prose work, the Zoonomia, and though he maintains it had no effect on him, it is not without interest that Darwin's first trial essay on the road to the Origin he entitled Zoonomia. Furthermore, in one of the unconsciously revelatory statements of which Darwin was sometimes capable he tells us, right after disclaiming that the Zoonomia had affected him, that "at this time I admired greatly the Zoonomia." [4] We need not at this point, however, raise the question of what the youth believed -- quite possibly he did not know himself. It is sufficient to establish the fact that such ideas were likely to have been assimilated early enough as to have had a familiar ring. The theory of evolution would thus have lost the shocking and heretical implications that it had for the uninitiated. Darwin himself at one point confesses, albeit a little reluctantly, that "it is probable that the hearing rather early in life such views maintained and praised may have favored my upholding them under a different form in my Origin of Species." Believing or unbelieving, young Charles had been raised in a family of somewhat unconventional and free-thinking traditions. We know further that he had a passionate attachment to nature and an equal revulsion against the conventional classical education of the time. At length he was packed off to Edinburgh in the hope that he would follow a medical career as his father and grandfather had done before him. Luckily for science, the sensitive youth could not endure the more ghastly aspects of medical practice and his stay at Edinburgh was short. In that brief period, however, he made the acquaintance of Dr. Robert Grant (1793-1874). Their relation was for a short time pleasant, but subsequently a coolness arose which persisted throughout their later years. [*] Grant was something of an anomaly in the Scotland of that day. In Paris he had picked up an acquaintance with Lamarckian evolution and was immensely enthusiastic about it. One day, walking with Darwin, he expounded the Lamarckian philosophy. Once more young Darwin listened, so he says, "in silent astonishment," again disclaiming any effect on his mind. Yet he listened, and listened well enough apparently to remember the episode into remote old age. He was then but a youth of sixteen; the voyage of the Beagle was still six years away. It is not without interest also that while Darwin was at Edinburgh savoring the joys of zoological observation with Robert Grant, a quite remarkable paper appeared in the Edinburgh New Philosophical Journal, a scientific magazine contributed to by some of Darwin's professors, and edited by one of them. There is little doubt that Darwin was acquainted with the journal in the year of its foundation. In his later life he made extended use of it. The paper of which we speak is remarkable in that it upholds the evolutionary hypothesis in the year 1826. [5] That the unknown author knew his views to be extravagantly heretical there can be no doubt. One suspects that he must have been well known to the editors in order to secure even anonymous publication. We know of one such likely person in the Edinburgh of that day: Robert Grant. Curiously enough the paper, perhaps because of its misleadingly innocent title, seems to have gone unnoticed by scientific historians. The writer apparently lays no claim to originality but upholds Lamarck. "The doctrine of petrifactions, even in its present imperfect condition, furnishes us with accounts that seem in favor of Mr. Lamarck's hypothesis. We, in fact, meet with the more perfect classes of animals, only in the more recent beds of rocks, and the most perfect, those closely allied to our own species, only in the most recent; beneath them occur granivorous, before carnivorous, animals; and human remains are found only in alluvial soil, in calcareous tuff, and in limestone conglomerates." [6] Referring to Lamarck as "one of the most sagacious naturalists of our day," this pioneer evolutionist continues: "The distinction of species is undoubtedly one of the foundations of natural history, and her character is the propagation of similar forms. But are these forms as immutable as some distinguished naturalists maintain; or do not our domestic animals and our cultivated or artificial plants prove the contrary? If these, by change of situation, of climate, of nourishment, and by every other circumstance that operates upon them, can change their relations, it is probable that many fossil species to which no originals can be found may not be extinct, but have gradually passed into others." [7] Here, early in English scientific literature -- before Lyell had attempted to elucidate the theories of Lamarck for the English public-the suspicious changeability of domesticated forms has been drawn to the attention of the public. It will re-emerge in the succession of Darwin's writings. Perhaps, considering that this essay was written in the heyday of catastrophism, one of its most astonishing features is its rejection of this point of view. "Out of the vast number of animal remains; our author tells us, "but few belong to species now living, and these only in the most recent rock formations.... [*] May this destruction, as is commonly received, have been the result of violent accidents and destructive revolutions of the earth, or does it not rather indicate a great law of nature, which cannot be discovered by reason of its remote antiquity?" [8] The unknown author is sure that "petrifactions" contain the history of the organic world and that this science along with the study of plant and animal distribution -- "organic geography" he calls it -- will reveal whether the ancient populations were controlled by the same distributional laws as those of the present. The paper is restrained and well-reasoned. Darwin himself was later to pay the most precise attention to distribution. Of interest, further, is the fact that Darwin was actively associated with the scientific life of Edinburgh in the same year that the anonymous essay appeared. There can be no doubt that he was acquainted with the just launched Edinburgh Journal, His biographer West, while failing to note the magazine specifically, makes quite clear that the subject of evolution hovered in the Edinburgh air. It is West's belief, certainly not belied by the material we have quoted, that it was here at Edinburgh that evolution became for Darwin "a living and potentially credible doctrine." [9] Yet this pleasant society was not to last. Tiring of the medical. round, Darwin drifted to Cambridge with the thought of entering the ministry, but he continued to cultivate naturalists, to dabble in geology, and to fear the wrath of his exasperated father who had grown weary of his eternal hunting and his lack of scholarly application. One thing, however, is significant: the boy attracted and held the attention of distinguished older men. They sensed something unexpressed within him. Through the good offices of the botanist Henslow and the winning over of his father by his uncle, Josiah Wedgwood, he was permitted to go as naturalist on the voyage of the Beagle, The ship sailed in 1831. III. Darwin's Intellectual Background One can, in a sense, regard the voyage of the Beagle as a romantic interlude. One can point out that every idea Darwin developed was lying fallow in England before he sailed. One can show that sufficient data had been accumulated to enable a man of great insight to have demonstrated the fact of evolution and the theory of natural selection by sheer deduction in a well-equipped library. All of this is. doubtless true. Yet it is significant that the two men who actually fully developed the principle of natural selection, Charles Darwin and Alfred Russel Wallace, were both travelers to the earth's farthest reaches, and both had been profoundly impressed by what they had seen with their own naked eyes and with the long thoughts that come with weeks at sea. It cannot be denied, however, that both had the additional advantage of literary counsel. Because of the impact their discovery made, there has been a tendency to think, in the case of Darwin in particular, that he personally devised all of the experiment and thought which went into the Origin of Species. Without wishing in the least to subtract from his greatness, let us continue our examination of the state of European thought in the year 1831. Darwin, in after years, sometimes spoke contemptuously of his Cambridge education, forgetting apparently that despite his opinion of the formal course work, he had been privileged to know there some of the finest scientific minds of the day and that the botanist Henslow had made his voyage on the Beagle possible. [10] One of these men, Adam Sedgwick, whom Darwin had accompanied on geological field trips, gave a surprising presidential address before the Geological Society of London early in 1830. It was surprising in that Sedgwick, who remained opposed to the evolutionary hypothesis throughout his life, really forecast the eventual triumph of uniformitarianism in geology, and organic evolution in biology. His remarks, perhaps, did not go unnoted by the youthful scholar who was soon to become a disciple of Lyell. Consider, for example, the following statement: "Each succeeding year places in a stronger point of view the importance of organic remains, when we attempt to trace the various periods and revolutions in the history of the globe. Crystalline rocks are found associated with the strata of almost every age; and the constant laws of combination which have produced a certain mineral form in the rocks of one era, may produce it again in another.... The great barriers, which the fancy or ingenuity of geologists has at different times set up between the mineral productions of successive periods, have been thrown down one after another...." [11] Here Sedgwick is confessing that one can no longer, as in earlier years, claim that the actual mineral composition of the strata differ from one past "world" to another. Instead, to discern accurately the nature of the lost creations one must rely upon the organic remains in the strata. It is at this point that Sedgwick, in a manner which he was to repeat more than once, comes to the very verge of the evolutionary abyss and then draws back. He writes: "When we examine a series of formations which are in contact, we constantly find them passing into each other: and when we place the groups of fossils derived from the successive terms of the series in the order of superposition, their passage is still more striking. 1 do not mean by this to vindicate the transmutation of species; because that doctrine is opposed by all the facts of any value in determining such a question.... I only wish to state a fact of general observation." (Italics mine. L.E.) First minerals had failed to differentiate separate, distinct episodes in the world of the past. Now, Sedgwick implies, the very fossils themselves suggest transitions rather than breaks in the record. From this he recoils, but feels constrained to venture: "I only wish to state a fact of general observation." That observation, which Sedgwick and most of his generation could not face, was to lead directly to the only possible explanation; that is, uniformitarianism in both geology and biology, the recognition that the successive worlds of the past were one continuous world which had been changing and evolving since time began. Thus, in one form or another, Darwin had unknowingly taken aboard the Beagle the three fragments of the lost chart of Smith, Cuvier, and Hutton. Particularly, he had taken them in the shape of Lyell's book, The Principles of Geology. The second volume containing the material on animal life and Lamarck's theories would reach him in South America. One other thing happened before he left. An anonymous but learned reviewer wrote in June of 1831 (Darwin would not leave until fall) a lengthy account of Sir John Richardson's Fauna Boreali Americani for the Edinburgh Review. Entitled "The Geography of Animal Life," [12] it gives in a succinct' summary all that was then known about the mystery of life on oceanic islands. The Edinburgh Review was a Whig organ and the Darwin family espoused the Whig point of view. There can be little doubt that Darwin was acquainted with this article. It might also be noted by way of anticipation that the Review was a strong advocate of the views of Thomas Malthus, and that William Paley, whose Natural Theology had been extensively studied by Darwin, was a convert to Malthusianism. The significance of this will concern us later. Here it will suffice to examine the essay on animal distribution. Although the anonymous writer, who obviously knows his subject, discreetly comments that the mode by which the distribution of animals has been effected "will probably remain forever concealed from human knowledge," he cannot resist encouraging a program to pierce this barrier of ignorance. He urges the assiduous collection of facts and he points out that it is most important to ascertain "the limits which nature has assigned to the variation in the specific characters of animals." He asks what may cause a peculiar variety of bird to be confined to the island of Madeira and what the significance of this fact may be. "Why," he continues, "are the pampas of the New World inhabited by quadrupeds entirely different from the species which occur in the plains of Tartary?" Returning in fascination to the subject of islands he puzzles over how "a mere speck in the vast world of waters" has received its flora and fauna. He recognizes, using the Mascarene archipelago as an example, that certain of these islands are volcanic and younger than the continents nearest to them, yet they are clothed with life. He discusses the possibility of oceanic transport of living seeds, or the dissemination of seeds by birds -- all subjects to be much written upon by Darwin. At last he confronts the puzzled reader with a total mystery. "Finally, that monstrous and extraordinary bird, the dodo, indigenous to the island under consideration, and which so greatly astonished the early settlers, could not have been carried from any other quarter of the world, because it was neither known previously, nor has it ever since been seen or heard of elsewhere." To this mystery there is only one key: evolution under conditions of isolation. During the next few years Darwin would examine with fascinated interest every island he came upon. In the Galapagos he would find a similarly rare and localized fauna. He would grasp there facts essential to the development of his theory. This Review article makes quite plain the kind of questions beginning to be asked in biology as Darwin sailed away in the Beagle. Remote archipelagoes had been found to contain species and even 'genera not to be found on the continents, yet some of these islands had been found to be geologically of much more recent origin than the continents. "Some recent speculators," the anonymous author confesses, "have argued from this the necessity of admitting the possibility of a comparatively modern creation of animal and vegetable life." English thought, one observes, is still couched in terms of creation rather than change. The dodo, for example, has not yet been seen to be a strangely altered member of the pigeon family. Nevertheless, it is questions of this nature which will lead inevitably in the direction of an evolutionary hypothesis. Among the other influences at work in young Darwin's mind was that of Alexander Humboldt. Humboldt was one of the last of the great travelers. As Ackerknecht has recently pointed out, Humboldt, to his contemporaries, was not a mere scientist, "he was the 'symbol' of science." [13] A man of wide-ranging intellect, he was an adept synthesizer and played a major role in the creation of what might be called the "religion" of science which "came to dominate nineteenth-century intellectual circles. "In thus popularizing science," Ackerknecht maintains, "Humboldt created the atmosphere in which later scientific mass movements like Darwinism could thrive." [14] Darwin himself had been so impressed by the Personal Narrative that he had investigated the possibility of voyaging to Teneriffe before the Beagle opportunity had presented itself. Humboldt's volume, in spite of its detailed observations, urges upon the reader a sweeping range of facts which can be systematically correlated. "The most curious geological phenomena are often," he says, "repeated at immense distances on the surface of the continents ... the accidental concurrence of the same causes must have everywhere produced the same effects; and amidst the variety of nature, an analogy of structure and form is ob- served in the arrangement of brute matter, as well as in the internal organization of plants and animals." Later the "rents on coasts," "the sinuosities of valleys," and the "aspects of mountains" will preoccupy Darwin in South America. Humboldt, also, is an observer of seed transport. He speaks of the Gulf Stream, depositing on the western shores of Ireland and Norway "the fruit of trees, which belong to the torrid zone of America." "On these same coasts, various kinds of tortoises," he claims, "are sometimes found that inhabit the waters of the Antilles." Humboldt is also quite aware of the part played by man in changing the face of the planet: "The naturalist is ex· posed to a thousand errors, if he loses sight of the changes which the intercourse between nations produces on the surface of the globe, We might be led to say, that man expatriating himself, is desirous that everything should change country with him, Not only plants, insects, and different species of small quadrupeds, follow him across the ocean; his active industry covers the shores with rocks that he has torn from the soil in distant climes." Once more we find Darwin at a later date observing in his Journal the spread of huge Old World thistles on the pampas, and the alteration of plant and animal life under European contact. Humboldt also called attention to the fact that the science of his day was "under great obligations to navigators who have accumulated an immense number of facts.. "But," Humboldt adds, "[we] must regret that hitherto naturalists have made so little use of their journals, which when examined anew may yield unexpected results." (Italics mine. L.E.) When Darwin turned to the amassing of factual material for his great work on the origin of species, he spent much time and effort combing in just this way the accounts of the early voyagers for data bearing on plant and animal diffusion and the peculiarities of island faunas. It is, therefore, perhaps not without significance that one of the books which the youthful Darwin so much admired should have contained this excellent advice. Humboldt's narrative is really something of a model for the Naturalist's Voyage around the World. We glimpse this in Darwin's transports of delight over the tropical scenery of Bahia. "I am," he wrote in his diary, "at present fit only to read Humboldt; he like another sun illumines everything I behold." [15] Curiously enough, Ackerknecht's observation that Humboldt's "great synthetic picture of the world ... omits nothing but one single item: man" has also been expressed of his scientific descendant, Darwin. One such critic has said of Darwin, "His was a world of insects and pigeons, apes and curious plants, but man as he exists had no place in it." That Darwin attempted to treat of man physically, did treat him from the evolutionary point of view, we know, but there is, nevertheless, considerable justice to the charge that he was a poor ethnologist. Whether the parallelism to Humboldt can be sustained this far as more than fortuitous there is no way of estimating. Like Ackerknecht, one can only wonder what the history and influence of ethnology might have been if Humboldt, the scientific idol of the early nineteenth century, had expressed more interest in its welfare. The writings which we have just examined have been selected merely to emphasize once more what we have observed in earlier chapters -- that great acts of scientific synthesis are not performed in a vacuum. The influences, the books, the personalities surrounding a youthful genius are always of the utmost interest in terms of the way his own intellectual appetites come to be molded. Darwin's impact upon biology was destined to be so profound that much of what he absorbed from others was remembered as totally his own achievement. This happened because many of the biological works written before the Origin of Species became old-fashioned and ceased to be read. The still widespread notion that Darwin drew all of his ideas from pure field observation has been furthered perhaps by Darwin's own seeming indifference to the history of the ideas with which he worked. Actually, however, he was a voracious and inquiring reader [16] as well as a good field observer. It was this combination that produced his master synthesis. Having glimpsed a youth already perfectly cognizant of the evolutionary hypothesis, whatever his own personal viewpoint may have been at the time he boarded the Beagle, we have every reason to assume that he was intellectually equipped to make the most of his opportunities from the start. There was the stimulus of an evolutionary tradition stemming from his own grandfather and, from across the Channel, the more extended speculations of Lamarck which be at least knew by hearsay. In addition, he was under the spell of a great voyager, Humboldt, who emphasized observation and the synthesis of related facts into broad generalizations wherever possible. It would be easy to get the impression from the first edition of the Origin of Species that Darwin conceived of the evolutionary theory solely by field observation in South America. That his belief in its possible truth had been strengthened in this manner is likely enough, but it does not negate the fact that he went aboard the Beagle already aware of an existing hypothesis which he might have the opportunity of testing in the field. His genius lay in the fact that he was willing to test it; no preconceived emotional revulsion hindered him, no appetite for any existing evolutionary theory prevented his development of a more satisfactory mechanism by which to explain its effects. Having made this background clear, we can now proceed to an examination of the events of the voyage itself. IV. The Voyage The development of the theory of natural selection is often dated casually from the time of the publication of the Origin of Species in 1859. Actually, however, its inception occurred far earlier than this date. Since Darwin discussed the subject with his intimates over a long period and it was rather widely known in professional circles that he was working on the "species problem," it is even difficult in some instances to know how far his influence extended before he published. There are hints in the Naturalist's Voyage which might well have been pondered over by a thoughtful man. Wallace had read the Voyage and knew by personal correspondence with Darwin that he entertained original ideas on the subject. In fact, the more one examines the relationship of the two men the more one is impressed with the likelihood that without the stimulus of Darwin, there might have been no Wallace, just as, without the stimulus of Wallace, Darwin might never have got around to formal publication. This episode is less one of independent invention than of what A. L. Kroeber has called "stimulus diffusion." There is no question that Wallace worked out the idea of natural selection independently but he might be said to have sensed perspicaciously that Darwin was entertaining a new theory of his own -- in fact, Darwin practically told him as much -- and thus his own eagerness was whetted. Furthermore, like Darwin, his writing shows the influence of Sir Charles Lyell. As a result of this web of relationships between Darwin and his friends, as well as some contradiction in the enormous array of documents which confront us, it is not always easy to pursue a simple and straightforward. narrative of events. Another complication lies in the fact that Darwin, hurrying ahead at the last under the pressure of Wallace's competition, maintained, at least to himself, that the Origin was merely an abstract of a longer work which would contain names, documentation, and historical references which he did not have the time or space to include in the Origin. As a consequence, since the "real" Origin remained a dream, its "Abstract," the published Origin, is, by modern standards, inadequately footnoted. In many instances we are left without a clue as to where Darwin secured his ideas, yet it is obvious in certain in stances that there were sources close at hand upon which he might have drawn. Darwin was generous in expressions of appreciation to such men as Lyell, for example, yet since these mostly occur as book dedications or in letters, they often throw inadequate light upon the use of specific ideas. Beginning with the diary kept by Darwin on the voyage, therefore, we shall try to make out what influences from the world around him he specifically records. In doing so, however, we must keep carefully in mind that Darwin, the naturalist observer, is looking on with a mind fresh from the European geological and biological controversies of his just completed student days. He is not, in other words, to be considered as a lonely genius of the Hudson or Thoreau literary type. "Rat catcher" though his father may have exasperatedly called him, this young man had impressed professors of the stature of Sedgwick and Henslow; he had bathed his mind in the intellectual currents that were beginning to stir the society of his day. Solitary by nature, it is probable that he never consciously realized the full debt he owed to his Edinburgh and Cambridge background. As we turn to the diary of the voyage and to Darwin's autobiography, we encounter almost immediately a contradiction between the statements contained in these documents and his late reminiscences to a correspondent of 1877. To this individual he had written, "When on board the Beagle I believed in the permanence of species, but as far as I can remember vague doubts occasionally flitted across my mind." Keeping this statement in mind let us examine both Darwin's little autobiography and the diary and notebooks of the voyage. They give quite a different picture. Captain Fitzroy of the Beagle, in addition, once said that he had often remonstrated with Darwin for expressing doubts upon the first chapter of Genesis. Let us take first the actual day-to-day references in the diary. We need not look for evolutionary statements directly expressed. They would have annoyed Fitzroy, and Darwin's log was part of the official record of the expedition and open by right to Fitzroy. Some of the entries, however, are most provocative. We must also bear in mind as we examine Darwin's remarks that they can be divided into two categories: those bearing on the proof that evolution has occurred, and those concerned with the actual search for the mechanism by which organic change is produced. It is the confusion between these two points which is probably responsible for some of Darwin's own contradictory statements of later years. Apparently he came to equate, in some instances, the discovery of natural selection with his belief in the reality of evolution. Actually, however, the diary and notebooks of the voyage, as well as one of Darwin's own remarks in his autobiography, suggest that he began with an evolutionary suspicion which grew stronger with his continued observations and led, finally, to the discovery of the principle of natural selection and its accompanying law of divergence. Darwin's diary, as early as 1832, records observations which clearly indicate his concentration upon subjects of primary significance to an evolutionist. He observes a snake with rudimentary hind limbs marking "the passage by which Nature joins the lizards to the snakes." [17] A month later he examines a serpent whose tail "is terminated by a hard oval point" which it "vibrates as those possessed with a more perfect organ are known to do." [18] Again, he is quick to note the various modifications among "three sorts of birds which use their wings for more purposes than flying, the Steamer (duck) as paddles, the penguin as fins, and the Ostrich (rhea) spreads its plumes like sails to the breeze." [19] The close observation of the diverse uses to which the same organ can be put by modification absorbed his fascinated attention. There can be little doubt, however, that Darwin's acceptance of the uniformitarian geology of Lyell and, finally, in November of 1832, his reception in Montevideo of Lyell's second volume of the Principles of Geology, which dealt with biological problems, enormously influenced his further development. In fact, as we have earlier seen, Lyell comes so close at times to the evolutionary viewpoint, including natural selection, that one is almost exasperated by his failure to make the connection. It is no wonder that Darwin, years after, expressed agreement with Judd that without the Principles of Geology the Origin of Species would not have been written. [20] Around Darwin as the voyage progressed were living illustrations of all his books had told him, along with many additional and unrecorded marvels to further stimulate his imagination. On the night watches aboard the Beagle or traveling through the thin desert air of the Andean uplands he tells us that "the whole of my pleasure was derived from what passed in my mind." [21] Five years in the great solitudes, shut out by the wall of illiteracy or prejudice from the possibility of being able to talk freely with his companions, whether the seamen of the Beagle or the gauchos amused by the mysterious doings of the naturalista, were destined to strengthen his patience and at the same time to promote those aloof and lonely habits which were to characterize him until the end of his life. Long afterward his son Francis was to speak of Darwin's winter morning walks in Kent -- walks taken so early that he used to meet the foxes trotting home at dawn. It is possible from the information Darwin has left us, and again making allowance for the educational back. ground that as a naturalist he already possessed, to interpret the successive stages of his thought in the development of the evolutionary hypothesis. There are, as we have earlier shown, two aspects of the problem: the demonstration of evolution itself as a process taking place in time and, second, the nature of the mechanism controlling it. So far as the voyage is concerned, Darwin succeeded in solving only the first aspect of the problem, that is, the actual demonstration of the likelihood that evolution had taken place. Nevertheless, as we shall see, he came, in the Galapagos, upon a key to the mechanism itself. V. South America As the Beagle had proceeded southward from Brazil, Darwin had participated in numerous landings and had also made long journeys on more than one occasion into the interior. He had become impressed, he informs us in the autobiography, "by the manner in which closely allied animals replace one another in proceeding southwards." [22] He had come to see, in other words, a moderate amount of varietal distinction among animals upon a single time level and differing only in their geographical location. Such distinctions suggested quite powerfully the local modification of a single species, rather than the separate independent creation of a new form differing only in a quite moderate fashion, or in a few insignificant characters, from a previously observed species farther to the north. Later, this impression was to be powerfully intensified upon his examination of the Galapagos fauna. Upon reaching and exploring the pampas, Darwin was struck by the presence in the Pampean geological formation of huge fossil Edentates possessing a kind of skin armor comparable to that of the existing armadillo from the same region.28 In other anatomical aspects, also, these animals seemed to bear some mysterious resemblance to their existing relatives. Still later, after Owen's identifications, he noted that this principle seemed to hold as well in the case of an extinct llama whose remains he discovered in Patagonia. In the first edition of the Journal of Researches he commented that "the most important result of this discovery is the confirmation of the law that existing animals have a close relation in form with extinct species." [24] Darwin in his Journal called this phenomenon "the law of the succession of types" and commented cryptically that it "must possess the highest interest to every philosophical naturalist." [25] His comment that this type of succession was first noted in Australia shows that he undoubtedly drew the idea from Sir Charles Lyell, who commented with interest on finds of extinct marsupials in Australian caves as proving that "the peculiar type of organization which now characterizes the marsupial tribes has prevailed from a remote period in Australia." [26] The idea itself originated with William Clift and was so acknowledged by both Lyell and Darwin. [27] Some confusion has arisen on this point because Wallace in his evolutionary paper of 1855 made considerable use of this idea in terms of suggesting evolutionary relationships. As a consequence. the development of the idea of succession has sometimes been attributed to him. There exists in the files of the London and Edinburgh Philosophical Magazine the summary of a paper given by Darwin before the Geological Society28 shortly after his return from the voyage of the Beagle. Part of the summary contains the following: "The author [C.D.] finally remarked, that although several gigantic land animals, which formerly swarmed in South America, have perished, yet that they are now represented by animals confined to that country; and which though of diminutive size. possess the peculiar anatomical structure of their great extinct prototypes." This statement is followed by a footnote which reads: "The relation between the extinct and living animals confined to America was first noticed ... by Mr. Brayley, in some remarks on a fossil vertebra from Eschscholtz Bay; probably referable to a species of Megatherium." Brayley, contemporaneously with Clift, had. grown interested in the regional succession of faunas and had raised the question "whether the Megatherium was coextensive on both continents with the extinct elephant or whether, like the sloths, and the ant-eaters ... to which it is allied, it was confined to the New World, where. alone the bones of the Megatherium also have yet been discovered." [29] Darwin, when he wrote Lyell about the law of succession in 1859 protesting Owen's claim to having originated the principle, [30] had apparently forgotten his own early paper and the reference to Brayley. The latter cannot be said to clearly formulate a principle, but there is no doubt that in the time it was written, and considering the paucity of reliable paleontological data from the Americas, Brayley had raised a legitimate and important question. Clift, in examining some cave remains sent him for identification from Australia, came to a more clear-cut decision. "New Holland [Australia] was, at a former period," he wrote, "distinguished from other parts of the world, by the same peculiarities in the organization of its animals, which so strikingly characterize it at the present day." [31] Clift points out in addition that certain of his marsupials were larger than present-day forms -- a fact which Darwin later observed to hold true for South America. We have seen that Darwin in his Journal of Researches (1839) had hinted cryptically that this phenomenon of successive related faunas in a given region was of great importance. He was aware of its evolutionary significance when he wrote, but at this early date chose to remain silent. In 1855, four years before the publication of the Origin of Species and before Wallace himself had discovered the principle of natural selection, the latter published "On the Law which has Regulated the Introduction of New Species," [32] It was the most elaborate statement of the principle that had been given up to that time, or, for that matter, since. Every species, Wallace says, can be shown to have "come into existence coincident both in space and time with a pre-existing closely allied species." Though Wallace expresses himself cautiously, he makes it plain that in the light of this principle, and taking due note of other phenomena such as rudimentary organs, new forms of life emerge gradually rather than by special creation. This paper, while not quite so original on the "law of succession" as some have imagined, is, nevertheless, an early indication of the direction in which Wallace's thought was flowing. Moreover, in its use of apt data upon animal and plant distributions and the significance of oceanic islands in relation to the geological past, it already reveals the interests which would bring fame to Wallace as one of the foremost students of animal distribution. In going forward to 1855 we have been forced to anticipate in order to give the full history of the law of succession. Darwin in South America had earlier grasped the resemblance existing between modem animals and those extinct forms lying beneath them in geological time. He expressed it as a question in his unpublished essay of 1842, the first prelude to the Origin. [33] "Although [the] creationist can, by the help of geology, explain much, how can he explain the marked relation of the past and present in [the] same area?" Darwin had grasped this principle of relationship between living and dead faunas as early as 1837, for he says in his first unpublished notebook, "Propagation explains why modern animals same type as extinct, which is law almost proved." [34] This question had become steadily more important as world research yielded evidence that the extinct faunas of the main continental areas differed from each other, but bore a marked relationship to the living inhabitants of the same continent. Brayley had raised the suspicion in connection with the Americas. Clift, using the cave discoveries of Major Thomas Mitchel, had demonstrated its reality in Australia. In 1844, in his second essay prior to the Origin, Darwin gives a remarkably full exposition of the evolutionary significance of this principle: "This general and most remarkable relation between the lately past and present mammiferous inhabitants of the three main divisions of the world is precisely the same kind of fact as the relation between the different species of the several subregions of anyone of the main divisions. As we usually associate great physical changes with the total extinction of one series of beings, and its succession by another series, this identity of relation between the past and the present races of beings in the same quarters of the globe is more striking than the same relation between existing beings in different subregions: but in truth we have no reason for supposing that a change in the conditions has in any of these cases supervened, greater than that now existing between the temperate and tropical, or between the highlands and lowlands of the same main divisions, now tenanted by related beings. Finally, then, we clearly see that in each main division of the world the same relation holds good between its inhabitants in time as over space." [35] Darwin, during his South American experience, saw in the case of both geographical variation and paleontological sequence the possibility of modification by organic change, but not dramatic special creations by supernatural means. The evidence for change was reasonably clear but not the mechanism; of this the Galapagos would supply a subtle hint. VI. The Galapagos After rounding the Horn the Beagle sailed a leisurely course northward along the west coast of South America. While Captain Fitzroy pursued the mapping and other observational activities for which the Beagle had been sent out by the Admiralty office, Darwin continued to make geological and zoological observations. He visited offshore islands and made short, high journeys into the Andes. Collecting shells in the valley of Copiapo he commented: "It was amusing to hear discussions concerning the nature of the fossil shells- whether or not they had been thus 'born by nature,' carried on almost in the same terms as were used a century before in Europe." [36] He noted that the Andean Cordillera constitutes a great natural barrier to life and that differences between the flora and fauna on opposite sides of the range were to be expected. By the time the Journal was published he was willing to hint obscurely in a footnote that "the changes might be considered as superinduced by different circumstances in the two regions during a length of time," provided one did not assume the immutability of species. [37] In September of 1835 the Beagle reached the Galapagos Archipelago 600 miles off the coast of South America and directly upon the Equator. These burnt-out volcanic chimneys, parched and blackened as an iron foundry, made a profound impression upon Darwin. The sequence of his travels had been such that his arrival could not have been better timed to impress upon his mind a series of facts, both geological and biological, which were necessary to the formulation of his theories. Many times over, in the later years, Darwin, in letters to correspondents and in his autobiography, was to emphasize the importance of the facts brought to his attention among the islands of this obscure archipelago. He wrote to his co-discoverer Wallace in 1859: "Geographical distribution and geological relations of extinct to recent inhabitants of South America first led me to the subject: especially the case of the Galapagos Islands." [38] He reiterated to Moritz Wagner in 1876 that "it would have been a strange fact if I had overlooked the importance of isolation, seeing that it was such cases as that of the Galapagos Archipelago, which chiefly led me to study the origin of species." [39] What Darwin has to say in his autobiography will gain in emphasis if we first place ourselves under the conditions encountered by the young naturalist in 1835 and try, as nearly as we can, to see the Galapagos fauna as he first saw it. He came to the islands already impressed by the similarity of the extinct armored glyptodonts to their living relative, the armadillo. He had seen the slow variation in the form of related species as one moved along the great distances of the South American coasts, or passed from one side of the great Andean mountain barrier to the other. He had obtained an impression of creatures, both from times remote and from the diverse conditions of the present, showing surprisingly similar types of structure-surprising, that is, if one had to assume the orthodox view that they were all totally distinct creations and in that sense unrelated to each other. He had stared at a penguin's wing and had perceived that by certain modifications a wing could be made to beat its way through either water or air. Was it logical to suppose that all these clever adaptations to circumstance had been plucked out of a vacuum? Were not these remarkable structures built on what was basically the same plan? And could not this plan be, perhaps, pulled this way or that way, distorted, remolded, made to fit the animal to some difficult environment? But if so, what influence was at work? Did life in some manner respond to the environment? Did the climate, the surroundings of an animal, in some manner impinge upon his protoplasm and slowly draw these modifications of structure out of him? It seemed fantastic. How could climate, about which people talked so glibly, adapt a woodpecker for climbing trees or a hummingbird to probe into a flower? By great good fortune we possess two letters which Darwin mailed from the west coast of South America shortly before the Beagle pressed on to the Galapagos. They give us some excellent glimpses into his state of mind just before entering upon his last great intellectual adventure of the voyage. Writing to his sister Susan from Valparaiso in the latter part of April 1835, Darwin describes some of his experiences in the high Andes. He tells her of procuring fossil shells at elevations of 12,000 feet. He is confident that specimens "will give an approximate age to these mountains, as compared with the strata of Europe." Furthermore, he is convinced that the Andes are young as mountains go in the world's time scale. "If this result shall be considered as proved," he continues, only half concealing his eagerness, "it is a very important fact in the theory of the formation of the world; because if such wonderful changes have taken place so recently in the crust of the globe, there can be no reason for supposing former epochs of excessive violence. [40] Here we see that young Darwin has totally abandoned the catastrophic doctrines which were still the orthodox viewpoint of English geology. There is no finer evidence of Darwin's many-sided abilities as an observer than his geological work among the Andes. Two months later he wrote to his friend and cousin, the Rev. W. D. Fox, that he had "become a zealous disciple of Mr. Lyell's views, as known in his admirable book." Then, as if it did not content him merely to proclaim himself a uniformitarian in geology, he adds mysteriously, "I am tempted to carry parts to a greater extent even than he does." [41]What remains so intriguing about this cryptic remark is that only a sentence or two later we discern for the first time in his thought a slight falling away of interest in pure geology. "I have a considerable body of notes together; but," he says, "it is a constant subject of perplexity to me, whether they are of sufficient value for all the time I have spent about them or whether animals would not have been of more certain value." [42] Charles Darwin, on that July day in Lima, had arrived at the crossroads of his career. With almost preternatural sensitivity he suddenly writes, "I look forward to the Galapagos with more interest than any other part of the voyage." [43] That he fully shared Lyell's views is evident, but what is of paramount interest is the fact that Lyell failed to go as far as Darwin at just one point in his system, and that was in the application of natural forces to explain the evolution of life. "I am tempted to carry parts to a greater extent even than he does," hinted Darwin and then, in the same paragraph of the same letter, his thoughts begin to turn to animals and whether he might better have devoted his attention to them. It is the only place in his writings where he shows signs of abandoning for a moment his lifelong interest in geology. This neglected communication is pregnant with the unspoken excitement which even after the passage of over a century can be felt hovering at the tip of Darwin's pen. Darwin landed at Chatham Island in the Galapagos on the seventeenth of September, 1835. He had looked forward to the adventure with eagerness, but it was largely because, freshly impressed with the paleontological record in South America, he had hoped to find Tertiary fossil beds in the islands. The expectation proved short-lived. The rocks of black lava were heated like a stove. "The country," he comments, "was compared to what we might imagine the cultivated parts of the Infernal regions to be:" In addition, the islands swarmed with reptiles. Meeting some Galapagos tortoises for the first time, he observes that "they were so heavy, I could scarcely lift them off the ground. Surrounded by the black lava, the leafless shrubs and large cacti, they appeared most old-fashioned antediluvian animals or rather inhabitants of some other planet." [45] In this strange little isolated world Darwin set immediately to work collecting all the animals, plants, insects, and reptiles he could locate. He visited several of the islands and collected upon all of them. In this work he made one serious mistake: he did not, until late In his visit, attempt to keep similar species from individual islands separately labeled in his collections. This situation quite clearly came about because Darwin -- although impressed from his South American experience with the evidence pointing toward plant and animal evolution -- had not as yet fully grasped the possibility of dissimilar paths of development being taken by related organisms In close proximity on nearby islets. Darwin was, In other words, still seeking for the key to evolution In the exterior environment, In climate, in the natural surroundings of a given area. He had not expected to observe, In this score of islands clustered together and containing less than 2,800 square miles all told, much In the way of regional distinctions. That the fauna might differ from that of the neighboring continent was to be expected, but scarcely this strange divergence over little patches of sea In a totally similar climate. Slowly, as Darwin talked with the local Inhabitants, a different and strange impression grew upon him-an impression destined to be confirmed and heightened after his return home, when the Intensive examination of his specimens was to begin. In one of his notebooks of 1835 he dwells on the fact that the Spaniards could distinguish from which island the huge tortoises had been brought, and he similarly notes, "Islands In sight of each other ... tenanted by ... birds but slightly differing in structure." [46] From this time on, the full force of his wide-ranging mind is turned upon the archipelago. Such facts as these, he grows powerfully aware, "would undermine the stability of species." [47] By the time that the first edition of the Journal of Researches was published, Darwin, when he came to the subject of the Galapagos, was willing to throw out several evolutionary hints. "There is a rat," he records, "which Mr. Waterhouse believes is probably distinct from the English kind; but I cannot help suspecting that it is only the same altered by the peculiar conditions of its new country." [48] The finches in particular fascinated him. They differed remarkably in the structure of their beaks. Some had small beaks like warblers, some had thick, massive beaks. In the end, Darwin wrote regretfully of his many species of finches that although he suspected certain of the distinct types were confined to separate islands, he "was not aware of these facts till my collection was nearly completed." [49] "It never occurred to me," he explained, "that the productions of islands only a few miles apart, and places under the same physical conditions would be dissimilar. [50] I therefore did not attempt to make a series of specimens from the separate islands." This statement is extremely revelatory. As we have previously intimated, Darwin had, up to this point, been looking at variation largely over the great vertical distance of past time or horizontally over wide geographic areas. Under such circumstances one was apt to invoke climatic change as the primary mechanism involved in evolution. Here, in the Galapagos, Darwin was brought up short by a new series of facts: variation in form under isolation with the physical environment remaining precisely the same. As Darwin himself was later to observe, "One might really fancy that from an original paucity of birds in this archipelago one species had been taken and modified for different ends." [51] Darwin at last was face to face with the greatest of the evolutionary mysteries. If life varied on the individual islands of an archipelago subjected to the same climatic conditions, what determined this variation? Darwin did not come to this problem by any great flash of insight. It was not his way. He tells us, more particularly in the later editions of the Naturalist's Voyage, that the Vice-Governor of the islands, Mr. Lawson, an Englishman, first called his attention to this puzzling inter-island variation. "I did not for some time pay sufficient attention to this statement," he confesses. As a consequence, most of Darwin's collections had been assembled and he was almost on the point of departure when the full import of this observation struck his attention. "It is the fate of every voyager; he complained in his Journal, "when he has just discovered what object in any place is worth his attention to be hurried from it." [52] Lest in the light of modem biology Darwin's reaction may appear slow, the following comment by Sir Joseph Hooker, one of England's outstanding botanists, may better reveal the state of knowledge upon species during this period. As late as 1843, having examined some of Darwin's plant collections; Hooker wrote to him, "I was quite prepared to see the extraordinary difference between the plants of the separate islands from your Journal, a most strange fact, and one which quite overturns all our preconceived notions of species radiating from a centre...." [53] It was upon that strange fact that Darwin was to meditate for the next twenty years after his return from the voyage of the Beagle. "It may be asked," he wrote in the first edition of the Origin of Species, "how has it happened, in the several islands situated within sight of each other, having the same geological nature, the same height, climate, etc., that many of the immigrants should have been differently modified, though only in a small degree. This long appeared to me a great difficulty, but it arises in chief part from the deeply seated error of considering the physical conditions of a country as the most important for its inhabitants...." [54] No clearer statement of the significance of the Galapagos experience could have been made by Darwin. The subject, he confesses, "haunted me." It haunted him around the world and back to England, where he opened his first notebook on the subject in 1837. He had passed beyond the environmentalism of Buffon and the earlier evolutionists, but the island mystery, that "great difficulty" of bird beaks and turtle shells continued to baffle him. "I worked on true Baconian principles," he tells us, "and without any theory collected facts on a wholesale scale." [55] The result of those efforts would be the making of the Origin of Species and to that labor we will now proceed. The voyage of the Beagle had turned a pleasant, somewhat idle youth into a man. It had given the man of uncanny and perceptive insight a chance to exercise his thought upon armadillos and glyptodonts, stones falling and falling without end in the Andean torrents, turtles and volcanoes and bird beaks. At home in England he would piece them together into a new synthesis and the thought of the world would never be the same afterwards. It would come about because he had excavated the carapace of an Edentate, watched, in an earthquake, the Andes pumping themselves higher, and had also read Lyell and Humboldt. The origins of his thought were as diverse as the fragments of the puzzle which he at last fitted together. It could scarcely have been otherwise. _______________ Notes: 1. Life and Letters of Thomas Henry Huxley, ed. by Leonard Huxley, London, 1913, Vol. 1, p. 137. 2. Op. cit., Vol. 3, p. 273. 3. Ibid., p. 321. 4. LLD, Vol. 1, p. 38. 5. P. H. Jesperson, "Charles Darwin and Dr. Grant," Lychnos, 1948-49. Vol. 1, pp. 159-67. 5 Anonymous, "Observations on the Nature and Importance of Geology: Edinburgh New Philosophical Journal, 1826, Vol. 1. pp. 293-302. 6. Ibid., pp. 297-98. 7. Op. cit., p. 298. * An Intriguingly similar remark in phrase and idea occurs in the next to the final paragraph of the Origin. 8. Ibid., p. 298. (Italics mine. L.E.) 9 .Geoffrey West, Charles Darwin, A Portrait, Yale University Press, 1938, p. 66. See also J. H. Ashworth, "Charles Darwin as a student in Edinburgh 1825-1827." Proceedings of the Royal Society of Edinburgh, 1935, Vol. 55. pp. 97-113. Professor Ashworth's data fully corroborate the views expressed above. 10. It was not that Darwin was ungrateful to these men as individuals. He simply failed to realize that they had been selected and assembled by a great university, irrespective of whether one approved of the curriculum of the time. 11. The Philosophical Magazine, 1830, Series 2, Vol. 7. pp. 306-307. 12. 1831, Vol. 53. pp. 328-60. 13. Erwin H. Ackerknecht, "George Forster, Alexander von Humboldt and Ethnology," Isis, 1955, Vol. 46, pp. 83-95. 14. Ibid., p. 92. 15. Charles Darwin's Diary of the Voyage of H.M.S. "Beagle," ed. by Nora Barlow, Cambridge University Press. 1933. p. 39. 16. In a letter to Huxley written In 1858 Darwin confides: "I have so repeatedly required to see old Transactions and old Travels, etc. that I should regret extremely, when at work at the British Museum, to be separated from the entire library." MLD, Vol. 1, p. 111. 17. D, p. 83. 18. Ibid, p. 106. 19. Ibid., p. 126. 20. John W. Judd, The Coming of Evolution, Cambridge University Press, 1912, p. 73. 21. H. E. Litchfield, A Century of Family Letters, 2 vols., Cambridge University Press, 1904, Vol. 1, p. 438. 22. LLD, Vol. 1, p. 82. 23. As bearing again upon the curiosity of the voyagers, it is interesting to note that almost one hundred years earlier Thomas Falkner had left us the following account of a glyptodont: "I myself found the shell of an animal, composed of little hexagonal bones, each bone an inch in diameter at least; and the shell was near three yards over. It seemed, in all respects, except its size, to be the upper part of the shell of the armadillo; which, in these times, is not above a span in breadth. Some of my companions found also, near the river Parana, an entire skeleton of a monstrous alligator.... Upon an anatomical survey of the bones, I was pretty well assured that this extraordinary increase [in size of bones] did not proceed from any acquisition of foreign matter; as I found that the bony fibers were bigger in proportion as the bones were larger.... These things are well known to all who live in these countries; otherwise, I should not have dared to write them," Darwin has occasionally been accredited with the first discovery of these creatures. Thomas Falkner, Description at Patagonia and the Adjoining Parts at South America, Hereford, Eng., 1774, p. 55. 24. Journal at Researches (1839), facsimile reprint of the first edition, Hafner Publishing Co., New York, 1952, p. 209. 25. Ibid., p. 210. 26. PG, Vol. 3, p. 421. 27. MLD, Vol. 1, p. 133. Clift, however, probably had gotten the idea from John Hunter. See the latter's Essays and Observations edited by Richard Owen, London, 1861, Vol. 1, pp. 290-91. The paper referred to was published in 1794. 28. A Sketch of the Deposits Containing Extinct Mammalia in the Neighbourhood of La Plata," 1837. Vol. 2, pp. 206-8. 29. E. W. Brayley, "On the Odour Exhaled from Certain Organic Remains In the Diluvium of the Arctic Circle, As Confirmatory of Dr. Buckland's Opinion of A Sudden Change of Climate at the Period of Destruction of the Animals to which they Belonged, etc. etc." The Philosophical Magazine, 1831. Vol. 9. p. 418. 30. MLD, Vol. 1. p. 133. 31. William Clift, "Report by Mr. Clift of the College of Surgeons, London, in Regard to the Fossil Bones Found In the Caves and Bone Breccia of New Holland; Edinburgh New Philosophical Journal, 1831, Vol. 10, pp. 394-96. 32. This paper, which first appeared in the Annals and Magazine of Natural History is today most generally accessible in A. R. Wallace's Natural Selection and Tropical Nature, Macmillan, London, 1895. 33. FO, p. 33, fn. 1. 34. LLD, Vol. 2, p. 5. 35. FO, p. 176. 36. JR. p. 43. 37. Ibid., p. 400. 38. MLD, Vol 1, pp. 118-19. 39. LLD, Vol. 3. p. 159. 40. LLD, Vol. 1, p. 261. 41. Ibid., p. 263. (Italics mine. L.E.) 42. LLD, Vol. I, (Italics mine. L.E.) 43. Ibid. 44. D, p. 334. 45. D, p. 335. 46. Charles Darwin and the Voyage of the "Beagle," ed. by Nora Barlow, Philosophical Library, New York, 1946, p. 246. 47. N, p. 247. See also Nora Barlow, "Charles Darwin and the Galapagos Islands," Nature, 1935, Vol. 136, p. 391. 48. JR, p. 460. 49. Ibid., p. 474. 50. Ibid. (Italics mine. L.E.) 51. Charles Darwin, A Naturalist's Voyage Around the World, 2nd ed., London: John Murray, 1889, p. 380. The Journal of 1839 does not contain so direct a statement though the implication is clear (p. 462). 52. JR, p. 474. 53. Leonard Huxley, Life and Letters of Sir Joseph Hooker, 2 vols., London, 1918, Vol. 1, pp. 436-37. (Italics mine. L.E.) 54. O, p. 339. (Italics mine. L.E.) 55. LLD, Vol. 1, p. 83.
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