and thus those who admit the unity of domestic races should be cautious in deriding the unity of wild ones.

Domestic races all exhibit adaptations to man's use or fancy, rather than to their own good. The key to this is man's power of selection: nature gives successive variations, man accumulates these, so making for himself useful breeds, and often (e.g. in sheep, cattle, roses, dahlias) profoundly modifies their character even in a single human lifetime; so that in all characters to which he attends, they may differ more than the distinct species of the same genera. Again, that unconscious selection which results from every one trying to possess and breed the best animals is yet more important than conscious selection. Two flocks of Leicester sheep, kept equally pure, appeared of quite different varieties after fifty years. Such slowly accumu lated change explains why we know so little of the origin of domestic races; and its absence in regions inhabited by uncivilised man explains why these yield no plants worth immediate culture. Human selection is facilitated (1) by the keeping of large numbers, since variations will be more frequent, and (2) by preventing free-intercrossing; some species vary, however, more than others.

Variation under Nature.-All similar organisms in nature present individual differences, more considerable than is usually supposed. No two blades of grass are alike, and far more marked differences often occur, several castes or varieties sometimes existing in the same sex. Between these castes, and much more frequently between forms which systematic botanists and zoologists rank as true species, perfectly intermediate forms may occur. No agreement about the definition of species (the amount of difference necessary to give any two forms specific rank) has ever been come to; thus, in the British flora alone, there are nearly two hundred disputed forms, and individual opinion is in these cases the only criterion. As long as a genus is imperfectly known, and its species founded upon few specimens, they appear clearly limited. But with fuller knowledge, intermediate forms come in, and doubts as to specific limits augment. The terms species and variety are thus arbitrarily given to sets of individuals more or less closely resembling each other. See VARIETY, SPECIES, GENUS.

Individual differences are thus of the highest importance, as the first steps towards the slightest varieties worth recording, these in turn towards more distinct and permanent varieties, these varieties again towards sub-species, and in the next stage to species; though extinction may often arrest the process.

The species which present most varieties are those which have the greatest geographical range, or the widest diffusion in their own territory, or which possess the greatest number of individuals. In the larger genera of each country the species vary more frequently than in the smaller genera; and in many respects the species of large genera present a strong analogy with varieties, which analogy is alone intelligible on the view that they once existed as mere varieties themselves.

Struggle for Existence.-All organic beings tend to increase with extreme rapidity, so that if they were not kept down, the earth would soon be covered by the progeny of a single pair. This is evidenced not merely by calculation, but by actual observation of the extraordinary rapidity with which plants and animals have spread, when introduced into new and favourable circumstances (e.g. thistles and rabbits into Australia).

Since organisms then are reproducing themselves so rapidly, and since all their offspring cannot escape their enemies, get food, and live, much less

leave progeny in turn-since, in other words, the doctrine of Malthus applies to animals and plants with manifold force (for these can have no artificial increase of food, and no prudential restraints on reproduction)-there must in every case be a struggle for existence, either of one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life; often, indeed, with all these at once, and that more or less intensely throughout the whole of life.

The checks which prevent increase are most obscure, and vary in each case. In all cases the amount of food, of course, gives the extreme limit. The youngest organisms generally suffer most; seedlings, for instance, are destroyed in vast numbers. Thus, even in a patch of ground purposely dug and cleared, where no choking from other plants could take place, 295 out of 357 seedling-weeds were destroyed, chiefly by slugs and insects. So, too, the stock of game on an estate depends chiefly upon the destruction of vermin. Climate, however, is highly important, and periodic seasons of extreme cold and drought seem the most effective of all checks-a severe winter sometimes destroying fourfifths or more of the birds of a locality. Epidemics, too, may occur, especially where numbers have inordinately increased. On the other hand, a large number of individuals of the same species is essential for its continued preservation.

The complex relations of all animals and plants to each other require illustration. The planting of part of a heath with Scotch fir leads to a profound alteration of its flora and fauna, while the growth of these firs again is wholly dependent upon the exclusion of cattle. Many flowers depend for fertilisation on the visit of a special insecte.g. red clover on humble-bees. But bees are destroyed by field-mice, and consequently protected by cats; hence, not only no bees, no clover, but also the more cats, the more clover! The struggle for life is most severe between individuals and varieties of the same species, and between the species of the same genus, since these tend to fill the same place in the economy of nature; hence we see the brown rat supplanting the black, and the hive-bee supplanting its Australian congener. The structure of every being is related to that of the others with which it competes, or from which it seeks to escape, or on which it preys; as is alike evident in the structure of the tiger and of the parasite which clings to his hair. So, too, the albumen of a seed is chiefly useful in favouring the young plant's struggle for light and air against the adult plants around.

Natural Selection.-But how will the struggle for existence act with regard to variation? Can the principle of selection, so potent in the hands of nian, apply under nature? Most efficiently so. Let us bear in mind (1) the constant occurrence of variation; (2) the infinite complexity of the relations in which organisms stand to each other, and to the physical conditions of life; and consequently (3) what infinitely varied diversities of structure might be useful to each being under changing conditions of life. Can it then be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each combatant in the great and complex battle of life should also occur in the course of many generations? And if such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having some advantage, however slight, have the best chance of surviving and of reproducing their kind, while injurious variations are destroyed? This preservation of favourable variations, and the destruction of injurious ones,

is termed Natural Selection, or less figuratively, the Survival of the Fittest.

Taking the case of a country undergoing a change of climate, the proportional numbers of its denizens would change, some species probably becoming extinct and these changes would in many ways affect the survivors. A further disturbance would come from the immigration of new forms; or if that were prevented, we should have places in the economy of nature which might be better filled up. Any slight favourable modification of the old species would tend to be preserved, and we have seen that changed conditions increase variability.

Nor are such changes necessary in order to leave places for natural selection to fill. No country can be named where the native inhabitants are perfectly adapted to their conditions and competitors, for as some foreigners have taken firm possession in every country, we may safely conclude that the natives might have been modified with advantage to resist them.

And when human selection has produced such great results, why may not natural? Human selection acts only for man's own good, on mere external and visible characters, and irregularly throughout a short period; natural selection acts for the good of the being itself, on the whole machinery of its life, and incessantly on the species, throughout almost infinite time. (It is important here to remember that the objection to this agency on the ground of its presumed insignificance, is identical with that so long but unsuccessfully employed against Lyell's explanation of the origin of the physical features of the globe by summing up the existing natural changes.)

Natural selection thus leads to the improvement of each creature in relation to its organic and inorganic conditions of life, and consequently in most cases to what must be regarded as an advance in organisation. Nevertheless, low and simple forms will long endure, if well fitted for their simple conditions.

Natural selection may modify the egg, seed, or young, as easily as the adult, and these modifications may effect through correlation the structure of the latter, and conversely.

Besides Natural, we have to consider Sexual Selection-i.e. not merely do individuals struggle for existence, but the males struggle for the females, and the most vigorous thus tend to leave most progeny. Special weapons, offensive and defensive, like the cock's spurs, the stag's horns, or the lion's mane, are used in this struggle, and the most useful variations are those which are transmitted. Again, just as man can in a short time give beauty to his domestic birds, so there is no good reason to doubt that female birds in thousands of generations, by selecting, as they are observed to do, the most melodious or beautiful males, might produce a marked effect, and many sexual differences are thus explained.

The theory of natural selection may be applied in special cases-e.g. (1) to explain the evolution of swift greyhound-like varieties of wolves; (2) to explain the origin and the excretion of nectar in flowers, its use to insects, the action of insects in transferring pollen from flower to flower, with its advantage in intercrossing; and the resultant modification and adaptation of flower and insect to each other by the preservation of advantageous variations.

The circumstances favourable to the production of new forms through natural selection are also reviewed. These are chiefly, great variability; large numbers of individuals; the complex effects of intercrossing; isolation in small areas, yet also extension over continental ones, especially if these

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vary in altitude; and considerable lapse of time. Rare species are shown to be in process of extinction. The divergence of character in domestic breeds, largely due to the fact that fanciers do not, and will not, admire a medium standard, but like extremes,' applies throughout nature, from the circumstance that the more diversified the descendants from any one species become in structure, constitution, and habits, by so much will they be better enabled to seize on many and widely diversified places in nature, and so to increase in numbers. Thus, taking a carnivorous animal which has reached the maximum numbers its territory will support, it is evident that it can succeed in increasing only by its varying descendants seizing places hitherto occupied by other animals. This must hold equally of all species, and is separately demonstrated for plants. The greatest amount of life can be supported by help of proportionally great diversification of structure; hence, in small areas where competition is severe, the inhabitants are extremely varied.

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The probable effects of the action of Natural Selection, through divergence of character and extinction, on the descendants of a ancestor are then discussed in detail by Mr Darwin with an illustrative diagram. This takes the form of a genealogical tree-the great tree of life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its everbranching and beautiful ramifications.'

Laws of Variation (see VARIATION).—Of the cause of most variations we are still ignorant, but the same laws appear to have acted in producing the lesser differences between varieties of the same species and the greater differences between species of the same genus. Changed conditions sometimes induce definite and permanent effects: habit, use, and disuse are potent in their effects. Specific characters are more variable than generic, and varietal than either. Rudimentary organs and secondary sexual characters are highly variable. Species closely related of similar constitution and similarly influenced, present analogous variations, and frequently exhibit characters which can only be explained as reversions to those of their ancient progenitors-e.g. zebra-like stripes on horses, or wood-pigeon's markings on fantails, tumblers, &c.

Difficulties and Objections.-In four chapters all the miscellaneous objections raised against the theory between 1859 and the appearance of the latest edition are successively stated, weighed, discussed, and met, as well as the much more serious difficulties pointed out by Darwin himself. These latter are, (1) the definiteness of species and the rarity of transitional forms; (2) the enormous degree of modification in habits and structure assumed by the theory, and the seeming improbability that Natural Selection should produce on the one hand an organ of such trifling importance as the tail of a giraffe, and on the other, an organ so wonderful as the eye; (3) the acquirement and modification through Natural Selection of such marvellous instincts as those of the bee; (4) the sterility of crossed species, and the fertility of crossed varieties. For these discussions, however, the reader must consult the work itself.

Imperfection of the Geological Record.-On the assumption of the extermination of an enormous number of intermediate varieties, which were the links between existing and remote ancestral forms -why, then, is not every geological formation charged with such links? Why does not every collection of fossils afford plain evidence of the gradation and mutation of the forms of life? Geology, assuredly, does not reveal any such finely graduated organic chain, and this is one of the most obvious and plausible objections to the

theory. The explanation offered is the extreme the almost incredible-imperfection of the geological record. Only a small portion of the globe has been geologically explored with care; only certain classes of beings have been fossilised; and the number, both of specimens and species yet discovered, is absolutely as nothing compared with the number which must have passed away during even a single formation. The Malay Archipelago equals in area the formations best known to us; its present condition represents that of Europe while Europe's strata were being deposited; its fauna and flora are among the richest on the globe, yet, even if all the species were to be collected which ever lived there, how imperfectly would they represent the natural history of the world! Only few species are preserved at all, and most of these in an imperfect manner; moreover, subsidence being almost necessary for the accumulation of rich deposits, great intervals of time must have elapsed between successive formations, so that during periods of elevation, when variation would be most frequent, the record is least perfect. Moreover, geological formations have not been continuously deposited; the duration of specific forms probably exceeds that of each formation; migrations have largely taken place; widely ranging species are most variable, and oftenest give rise to new species; varieties have been at first local; and finally, it is probable that periods of modification are short as compared with periods of permanence. Hence we cannot find innumerable varieties, and any linking variety between two forms is, of course, ranked as a distinct species, for the whole chain cannot be permanently restored. Thus the geological record is a history of the world indeed, but one imperfectly kept, and written in a changing dialect; of this history we possess the last volume only, relating to two or three countries. Even of this volume only here and there has a short chapter been preserved, and of each page only here and there a few lines.

Geological Succession of Organic Beings (Distribution in Time).-The preceding difficulties excepted, the facts of paleontology agree admirably with the theory. New species come in slowly and successively; they change in different rates and degrees; old forms pass through rarity to extinction, and never reappear; dominant forms spread and vary, their descendants displacing the inferior groups, so that after long intervals of time the productions of the world appear to have changed simultaneously. The most ancient forms differ most widely from those now living, yet frequently present characters intermediate between groups now widely divergent, and they resemble to a remarkable extent the embryos of the more recent and more highly specialised animals belonging to the same classes. These laws, and, above all, the important law of the succession of the same types within the same areas during the later geological periods, and most notably between the Tertiary period and the present time (e.g. fossil and recent marsupials in Australia, and edentates in South America), cease to be mysterious, and become at once thoroughly intelligible on the principle of inheritance, and on that alone.

[Since the publication of the Origin of Species in 1859, paleontological research has been constantly furnishing the most triumphant verification of these views. The imperfection of the geological record was SO far from overestimated that Huxley (Science and Culture, 1880), in comparing our present knowledge of the mammalian Tertiary fauna with that of 1859, states that the results of the investigations of Gaudry, Marsh, and Filhol are as if zoologists were to become acquainted with a country hitherto unknown, as rich in novel forms of life as Brazil or South Africa once were to

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Europeans.' Gaudry has found the intermediate stages by which civets passed into hyænas; Filhol has disinterred still more remote ancestral carnivores; while Marsh has obtained a complete series of forms intermediate between that, in some respects, most anomalous of mammals, the horse, and the simplest five-toed ungulates (see MAMMALIA). Again, Darwin's belief that the distinctness of birds from all other vertebrates was to be accounted for by the extinction of a long line of progenitors connecting them with reptiles, was in 1859 a mere assumption; but in 1862 the long-tailed and intensely reptilian bird Archeopteryx (q.v.) was discovered, while in 1875 the researches of Marsh brought to light certain cretaceous birds, one (Hesperornis) with teeth set in a groove, the other (Ichthyornis) with teeth in sockets, and with bi-concave vertebræ. Besides these reptilian birds, bird-like reptiles have similarly been forthcoming, and the hypothesis of Darwin is thus admirably verified. Considerable light, too, has been thrown on the pedigree of crocodiles; ammonites, trilobites, and other invertebrates have been arranged in series, while important collateral evidence is also furnished by persistent types' such as Ceratodus, Beryx, Nautilus, Lingula, &c., which have survived-we must assume by ordinary generation-almost completely unchanged since remote geological periods. On such grounds, therefore, Huxley asserts (op. cit.) that 'on the evidence of paleontology, the evolu tion of many existing forms of animal life from their predecessors is no longer an hypothesis, but an historical fact; it is only the nature of the physiological factors which is still open to discussion.']

Geographical Distribution.-Neither the similarity nor the dissimilarity of the inhabitants of various regions, whether of land or sea, can be accounted for by identity or differences of climate, or other physical conditions, but both are related in the most striking degree to the absence or presence of barriers to migration between those regions. Within the same area there exists the most marked affinity among the species, though these differ from place to place. Species appear to have arisen in separate definite centres, the few apparent exceptions being accounted for by migration and dispersal, followed by climatic and geographical changes. But for a summary of our knowledge of the existing mode of distribution of organic life, and of the way in which that distribution has been effected, as well as of the very important bearing of these facts upon the theory of evolution, which they may be said, indeed, more than any other class of facts, to have suggested, see the article GEOGRAPHICAL DISTRIBUTION.

Morphological Arguments.-The physiological and distributional lines of argument being summarised, those furnished by morphology, although not less numerous and highly important, can only be very briefly outlined. These are mainly four, and are derived from (a) Classification, (b) Homologies, (c) Embryology, (d) Rudimentary Organs.

(a) Classification. Naturalists arrange the species, genera, and families in each class, on what is called the Natural System. But what is meant by this system? Is it, after all, merely an artificial scheme for enunciating general propositions, and of placing together the forms most like each other? or does it, as many believe, reveal the plan of creation? The grand fact of classification is, that organic beings, throughout all time, are arranged in groups subordinated under other groups-individuals under varieties, and these again under species; species under genera; genera under subfamilies, families, and orders; and all under a few grand classes. The nature of all these relationships-the rules followed and the difficulties met

by naturalists in their classifications the high value set upon constant and prevalent structures, whether these be of great or little use, or, as with rudimentary organs, of none at all the wide opposition in value between such misleading resemblances of adaptation, as, for instance, the fishlike form of whales, and such characters of true affinity as are afforded by the structure of their circulatory or respiratory system-all these receive a simple and natural explanation on the view of the common descent of allied forms with modification through variation and natural selection; while it is to be noted that no other explanation has ever even been attempted. The element of descent, too, is already used in linking all the sexes, ages, forms, and varieties of the same species, widely though these (e.g. Cirripedes) may differ from each other in structure and we have only to extend it to understand the meaning and origin of the Natural System.

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(b) Homology. The members of the same class, independently of their habits of life, resemble each other in their general plan of organisation. Thus, the hand of man, the digging-paw of the mole, the leg of the horse, the paddle of the porpoise, and the wing of the bat, are all constructed on the same pattern, bone corresponding to bone. Similarly with the hind-limb. Again, the mouths of insects are of innumerable varieties of form and usewitness the long spiral trunk of a moth, and the great jaws of a beetle-yet these are formed by modifications of an upper lip, mandibles, and two pairs of maxillæ. And so it is with the limbs of crustaceans, or the flowers of plants; in fact, with the organs of every class of beings.

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This conformity to type is powerfully suggestive of true relationship, of inheritance from a common ancestor; it admits, in short, as no one indeed denies, of a simple explanation in terms of the evolutionary theory, and thus strengthens that theory not a little. Attempts have been made to explain this unity of plan in two other ways-first, by assuming it due to utility, which is negatived by the facts, since organs of identical use (e.g. the wings of a bird and those of a butterfly) very frequently do not conform to the same type at all; secondly, by attributing it to a unity of design, which, however, (a) instead of being always maintained, as it should be, on the theory, is not unfrequently quite lost in highly specialised forms and which, even if it always existed, (b) would directly suggest the unity of descent, the design thus serving only to mislead the anatomist.

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Serial Homology, too, has to be accounted forthat unity of type which is found on comparing the different parts and organs in the same individual, so that the wonderfully complex and varied jaws and legs of a lobster, or the widely different leaves, sepals, petals, stamens, and pistils of a flower, are all found to be modifications of a simple limb, and a simple leaf-organ respectively. Not only are such metamorphoses apparent on comparison, but they can be actually observed to occur during the development of each individual; is then the term metamorphosis to have a mere metaphorical meaning when applied to the species, or has it not actually arisen in past time, through the natural selection and transmission of advantageous variations?

(c) Development.-It has been already indicated that the serially homologous parts in the same individual are alike during an early embryonic period, as also are the homologous organs in animals which, like bat, horse, and porpoise, may be widely differentiated in adult life. So closely, too, do the embryos of the most distinct species belonging to the same class resemble each other, that even Von Baer was unable to distinguish whether two un

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labelled specimens were lizards, birds, or mammals. This law of embryonic resemblance holds very widely-e.g. with young crustaceans. The embryo often retains within the egg or womb structures which are of no service to it, either at that or at a later period of life, like the transitory gill-arches of birds or mammals; while, on the other hand, larvæ (e.g. of insects), which have to provide for their own wants, undergo complete secondary adaptation to the surrounding conditions. The process of development goes from the general to the special; thus there is generally an advance in organisation. In peculiar conditions, however, degeneration may occur. All these facts are readily explained on the principle of successive slight variations not necessarily or generally supervening very early in life, and inherited at a corresponding period; hence it is in the highest degree probable that most embryonic stages show us more or less completely the progenitor of the group in its adult state; and embryology thus rises greatly in interest. See EMBRYOLOGY.

(d) Rudimentary Organs.-Rudimentary, atrophied, and abortive organs, bearing the plain stamp of inutility, are so extremely common that it is impossible to name a higher animal in which none occurs. The mammæ of male mammals, the hindlegs of boas, the wings of many birds, or the teeth of foetal whales, and the upper incisors of unborn calves, are familiar instances. Such organs are intelligible on the evolutionary theory, and on that theory alone.

Recapitulation and Conclusion.-After tersely summing up the preceding mass of evidence, Darwin concludes by pointing out (a) that the theory of evolution by natural selection is no more inimical to religion than is that of gravitation, to which the same objection was strongly raised; (b) its revolutionary influence on the study of all departments of natural history; (c) on Psychology (q.v.); (d) on the origin of man and his history (see MAN); (e) on our theories of future progress.

Envoy. It is interesting to contemplate a tangled bank clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; and Inheritance, which is almost implied by reproduction; Variability from the indirect and direct action of the conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms, or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.'

The stormy reception of the Origin of Species, the controversies to which it gave rise, its rapid and widespread acceptance, helped as it was by the independent support, yet generous self-abnegation, of Mr Wallace, and the powerful advocacy of Huxley, Hooker, Asa Gray, and others, are all recorded in Darwin's Life. Of the proposed expansion of the Origin, only the first chapter actually

appeared, as Variation of Animals and Plants under Domestication (see VARIATION); but in Fertilisation of Orchids, Forms of Flowers, Insectivorous Plants, Climbing Plants, Movement in Plants, we have a series which not only greatly developed Darwin's favourite study of adaptations, and with it enormously strengthened his general theory, but gave to the arid field of botany the interest and freshness of a new intellectual spring (see BOTANY). Again, the very difficulties which he felt to be presented to his theory by the complex phenomena of bee and ant society led him onwards, till he reached the problems of mind and language; the obvious and burning question of the origin of man had also to be faced, and thus we had the Descent of Man and the Expression of the Emotions.

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Before conclusion, justice demands, if not discussion, at least mention of some of the more important criticisms which have been urged against Darwin's theory. That which Darwin himself seems to have felt as most serious was made by Fleeming Jenkin, who laid stress on the tendency to swamping any individual variation, however advantageous, through intercrossing. Mr Mivart's Genesis of Species next engaged him most; Darwin's replies to these and other criticisms up to 1872 will be found in the final edition of the Origin of Species. In his essay in Darwin's Life, Huxley says, 'I venture to affirm that so far as all my knowledge goes, all the ingenuity and all the learning of hostile critics have not enabled them to adduce a single fact of which it can be said this is irreconcilable with the Darwinian theory;' while Mr Ray Lankester still more recently assures us that since its first publication in 1859 the history of Darwin's theory has been one of continuous and decisive conquest, so that at the present day it is universally accepted as the central, all-embracing doctrine of zoological and botanical science.'

As a matter of fact, however, this universal acceptance' is not without its universally distributed exceptions. Some of Darwin's contemporaries have withheld their adhesion-e.g. Virchow in Germany, Owen and Cleland in Britain, and the older French naturalists; nor can the critical and controversial writings of Mivart, the Duke of Argyll, Samuel Butler, and others, be thus wholly ignored. Constructive criticism is also busy. On one hand certainly we have the ultraDarwinian speculations of Weismann, warmly accepted by Lankester and others; but on the other, attempts are again being made, and with increasing frequency, to restate the theory of evolution more or less completely in non-Darwinian terms. Thus, following up the doubt which occasionally troubled Mr Darwin's recent years, that he had assigned too little importance to the modifying factors of use and disuse, of environment, &c., we have Mr Spencer re-entering the field; in America an active Neo-Lamarckian school has also arisen, which lacks neither knowledge nor thoughtfulness; in Germany we owe new constructive efforts to Nägeli and Semper, and more recently to Eimer; while in Britain, complementary hypotheses have been propounded by Romanes, Sutton, Gulick, Geddes, &c. But such proposed positive contributions to the evolutionary theory fall rather to be treated under EVOLUTION.

See BIOLOGY, BOTANY, EVOLUTION, ENVIRONMENT, HEREDITY, GEOGRAPHICAL DISTRIBUTION, ZOOLOGY, and other articles. Besides the works of Darwin himself, and those of Alfred Russell Wallace (from Natural Selection in 1870 to Darwinism in 1889), with the special treatises referred to under the above-mentioned and minor articles (e.g. FERTILISATION), see F. Darwin's Life of Charles Darwin; also minor Lives by Grant Allen and Bettany. Of other expository literature may be

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mentioned Haeckel's Generelle Morphologie and Natural History of Creation; Huxley's Lay Sermons, American Addresses, Science and Culture, Anatomy of Invertebrated Animals; also his essay On the Reception of the Origin of Species in Darwin's Life, vol. ii.; Obituary Notice of Struggle for Existence, a Programme (Nineteenth Century, Charles Darwin in Proc. Roy. Soc. (Lond. 1888); and 1888). Weismann's Studies in the Theory of Descent (1880-82), and for more recent developments his subsequent papers (see HEREDITY, REPRODUCTION), must also be noted. Romanes' Scientific Evidences of Organic Evolution, Lankester's Degeneration (both Nature series), Schmidt's Doctrine of Descent and Darwinism, Fiske's Darwinism and other Essays, are examples in English of an abundant and more popular literature, in which the writings of Mr Grant Allen and Dr A. Wilson are also specially known, and which is likewise abundant in Germany, France, and Italy.

Of controversial writings may be cited Mivart's Genesis of Species, Lessons from Nature, &c.; the Duke of Argyll's Unity of Nature, as well as the review articles of both writers. See also Butler's Evolution, Old and New, and Luck or Cunning. For the literature of the more constructive attempts referred to, see EVOLUTION. For general bibliography Bettany's Life of Darwin is most accessible; while complete help will be obtained from Seidlitz, Die Darw. Theorie (Leip. 1875), and from the Naples Jahresbericht f. Zoologie; preferably, however, since 1886 from the Zoological Record.

Darwin Sound and MOUNT DARWIN are on the SW. side of King Charles's South Land, Tierra del Fuego. The mountain rises 6800 feet.

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Dasent, SIR GEORGE WEBBE, was born in 1820 at St Vincent in the West Indies, of which island his father was attorney-general. He was educated at Westminster School and King's College, London; 1840; and was called to the bar at the Middle graduated B.A. at Magdalen College, Oxford, in Temple in 1852, in which year also he received his degree of D.C.L. He acted some years as assistant-editor in the Times office, and married a sister of its editor, Mr Delane. An accomplished linguist, he had often acted as examiner in English and modern languages for civil service appointments, when he was appointed a Civil Service Commissioner in 1870, and knighted 'for public services' in 1876. Already in 1842 he published a translation of The Prose or Younger Edda which was followed by an essay, 'The Norsemen, in the Oxford Essays (1858); Popular Tales from the Norse, with an Introductory Essay on the Origin and Diffusion of Popular Tales (1859), and Tales from the Fjeld (1874), both from the Norwegian of Asbjörnsen; translations from the Icelandic of the Saga of Burnt Njal (1861), and the Story of Gisli, the Outlaw (1866); and an Introduction and Life of Cleasby, prefixed to Vigfusson's completion of Cleasby's unfinished Icelandic-English Dictionary (1874). Sir George Dasent has also written several fair novels. His famous introduction to Asbjörnfolklore, being an admirable exposition of the sen's Popular Tales was a solid contribution to Aryan theory of story-transmission as advocated by Grimm and Max Müller.

Dash, COUNTESS, the name under which Gabrielle Anna Cisterne de Courtiras, Vicomtesse de Saint-Mars, published a series of novels, many of which were readable, if of but slender literary merit. She was born at Poitiers, August 2, 1804, of a noble family, married early, and took to literature for a living after the loss of her property, writing sometimes as many as five or six novels a year. She died 11th September 1872. Her stories deal almost exclusively with the aristocratic world and its more or less illegitimate liaisons. They have a certain brightness and vigour, but lack reality, and are peopled by a crowd of stilted puppets rather than living men and women. Of her numberless books may only be mentioned