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and thus those who admit the unity of domestic leave progeny in turn-since, in other words, the
with manifold force (for these can have no artificial
Such slowly accumu dug and cleared, where no choking from other plants
fifths or more of the birds of a locality. Epidemics,
the others with which it competes, or from which
So, too, the
Natural Selection.—But how will the struggle
changing conditions of life. Can it then be thought Struggle for E.cistence.—All organic beings tend improbable, seeing that variations useful to man to increase with extreme rapidity, so that if they have undoubtedly occurred, that other variations were not kept down, the earth would soon be useful in some way to each combatant in the great covered by the progeny of a single pair. This is and complex battle of life should also occur in the evidenced not merely ly calculation, but by actual
course of many generations? And if such do observation of the extraordinary rapidity with occur, can we doubt (remembering that many more which plants and animals have spread, when in- individuals are born than can possibly survive) troduced into new and favourable circumstances that individuals having some advantage, however (e.g. thistles and rabbits into Australia).
slight, have the best
chance of surviving and of Since organisms then are reproducing themselves reproducing their kind, while injurious variations so rapidly, and since all their offspring cannot are destroyed? This preservation of favourable escape their enemies, get food, and live, much less I variations, and the destruction of injurious ones,
is termed Natural Selection, or less figuratively, vary in altitude; and considerable lapse of time. the Survival of the Fittest.
Rare species are shown to be in process of extincTaking the case of a country undergoing a tion. The divergence of character in domestic change of climate, the proportional numbers of breeds, largely due to the fact that fanciers do its denizens would change, some species probably not, and will not, admire a medium standard, but becoming extinct—and these changes would in like extremes,' applies throughout nature, from the many ways affect the survivors. Å further dis- circumstance that the more diversified the descendturbance would come from the immigration of new ants from any one species become in structure, forms; or if that were prevented, we should have constitution, and habits, by so much will they places in the economy of nature which might be be better enabled to seize on many and widely better filled up. Any slight favourable modifica- diversified places in nature, and so to increase in tion of the old species would tend to be preserved, numbers. Thus, taking a carnivorous animal which and we have seen that changed conditions increase has reached the maximum numbers its territory variability.
will support, it is evident that it can succeed in Nor are such changes necessary in order to leave increasing only by its varying descendants seizing places for natural selection to fill. No country can places hitherto occupied by other animals. This be named where the native inhabitants are per must hold equally of all species, and is separately fectly adapted to their conditions and competitors, demonstrated for plants. The greatest amount of for as some foreigners have taken firm possession life can be supported by help of proportionally great in every country, we may safely conclude that the diversification of structure; hence, in small areas natives might have been modified with advantage where competition is severe, the inhabitants are to resist then).
extremely varied. And when human selection has produced such The probable effects of the action of Natural great results, why may not natural ? Human Selection, through divergence of character and selection acts only for man's own good, on mere extinction, on the descendants of external and visible characters, and irregularly ancestor are then discussed in detail by Mr Darwin throughout a short period ; natural selection acts with an illustrative diagram. This takes the form for the good of the being itself, on the whole of a genealogical tree, the great tree of life, which machinery of its life, and incessantly on the fills with its dead and broken branches the crust of species, throughout almost infinite time. (It is the earth, and covers the surface with its everimportant here to remember that the objection to branching and beautiful ramifications.' this agency on the ground of its presumed insigni Laws of Variation (see VARIATION).–Of the ficance, is identical with that so long but unsuc cause of most variations we are still ignorant, but cessfully employed against Lyell's explanation of the same laws appear to have acted in producing the origin of the physical features of the globe by the lesser differences between varieties of the same summing up the existing natural changes.)
species and the greater differences between species Natural selection thus leads to the improvement of the same genus. Changed conditions sometimes of each creature in relation to its organic and induce definite and permanent effects : habit, use, inorganic conditions of life, and consequently in and disuse are potent in their effects. Specific most cases to what must be regarded as an advance characters are more variable than generic, and in organisation. Nevertheless, low and simple varietal than either. Rudimentary organs and forms will long endure, if well fitted for their secondary sexual characters are highly variable. simple conditions.
Species closely related of similar constitution and Natural selection may modify the egg, seed, or similarly influenced, present analogous variations, young, as easily as the adult, and these modifica and frequently exhibit characters which can only tions may effect through correlation the structure be explained as reversions to those of their ancient of the latter, and conversely.
progenitors-e.g. zebra-like stripes on horses, or Besides Natural, we have to consider Sexual wood-pigeon's markings on fantails, tumblers, &c. Selection-i.e. not merely do individuals struggle Difficulties and Objections.-In four chapters all for existence, but the males struggle for the the miscellaneous objections raised against the females, and the most vigorous thus tend to leave theory between 1859 and the appearance of the most progeny.
Special weapons, offensive and latest edition are successively stated, weighed, disdefensive, like the cock's spurs, the stay's horns, cussed, and met, as well as the much more serious or the lion's mane, are used in this struggle, difficulties pointed out by Darwin himself. These and the most useful variations are those which latter are, (1) tlie definiteness of species and the are transmitted. Again, just as man can in a rarity of transitional forms; (2) the enormous short time give beauty to his domestic birds, so degree of modification in habits and structure there is no good reason to doubt that female birds assumed by the theory, and the seeming improbain thousands of generations, by selecting, as they bility that Natural Selection should produce on the are observed to lo, the most melodious or beauti one hand an organ of such trifling importance as ful males, might produce a marked effect, and the tail of a giraffe, and on the other, an organ so many sexual differences are thus explained.
wonderful as the eye ; (3) the acquirement and Tlie theory of natural selection inay be applied modification through Natural Selection of such in special cases—e.g. (1) to explain the evolution marvellous instincts as those of the bee; (4) the of swift greyhound-like varieties of wolves ; (2) to sterility of crossed species, and the fertility of explain the origin and the excretion of nectar in crossed varieties. For these discussions, however, flowers, its use to insects, the action of insects in the reader must consult the work itself. transferring pollen from flower to flower, with its Imperfection of the Geological Record.-On the advantage in intercrossing; and the resultant assumption of the extermination of an enormous modification and adaptation of flower and insect number of intermediate varieties, which were the to each other by the preservation of advantageous links between existing and remote ancestral forms variations.
-why, then, is not every geological formation The circuinstances favourable to the production charged with such links? Why does not every of new fornis through natural selection are also collection of fossils afford plain evidence of the reviewed. These are chiefly, great variability ; gradation and mutation of the fornis of life? large numbers of individuals; the complex effects Geology, assuredly, does not reveal any such finely of intercrossing; isolation in small areas, yet also graduated organic chair, and this is one of the extension over continental ones, especially if these / most obvious and plausible objections to the
theory. The explanation offered is the extreme- Europeans. Gaudry has found the intermediate the almost incredible-imperfection of the geological stages by which civets passed into hyænas; Filhol record. Only a small portion of the globe has been has disinterred still more remote ancestral carni. geologically explored with care; only certain classes vores; while Marsh has obtained a complete series of of beings have been fossilised ; and the number, | forms intermediate between that, in some respects, both of specimens and species yet discovered, is most anomalous of mammals, the horse, and the simabsolutely as nothing compared with the number plest five-toed ungulates (see MAMMALIA). Again, which must have passed away during even a single Darwin's belief that the distinctness of birds from formation. The Malay Archipelago equals in area all other vertebrates was to be accounted for by the the formations best known to us; its present extinction of a long line of progenitors connecting condition represents that of Europe while Europe's them with reptiles, was in 1859 a mere assumption ; strata were being deposited ; its fauna and flora but in 1862 the long-tailed and intensely reptilian are among the richest on the globe, yet, even if all bird Archæopteryx (q.v.) was discovered, while in the species were to be collected which ever lived 1875 the researches of Marsh brought to light there, how imperfectly would they represent the certain cretaceous birds, one (Hesperornis) with natural history of the world ! Only few species are teeth set in a groove, the other (Ichthyornis) with preserved at all, and most of these in an imper- teeth in sockets, and with bi.concave vertebrae. fect manner; moreover, subsidence being almost Besides these reptilian birds, bird-like reptiles have necessary for the accumulation of rich deposits, similarly been forthcoming, and the hypothesis of great intervals of time must have elapsed between Darwin is thus admirably verified. Considerable successive formations, so that during periods of ele- light, too, has been thrown on the pedigree of vation, when variation would be most frequent, the crocodiles ; ammonites, trilobites, and other inrecord is least perfect. Moreover, geological forina vertebrates have been arranged in series, while tions have not been continuously deposited; the important collateral evidence is also furnished by duration of specific forms probably exceeds that of persistent types' such as Ceratodus, Beryx, each formation; migrations have largely taken Nautilus, Lingula, &c., which have survived-we place; widely ranging species are most variable, must assume by ordinary generation--almost comand oftenest give rise to new species ; varieties pletely unchanged since remote geological periods. have been at first local ; and finally, it is probable On such grounds, therefore, Huxley asserts (op. cit.) that periods of modification are short as compared that 'on the evidence of palæontology, the evoluwith periods of permanence. Hence we cannot find tion of many existing forms of animal life from innumerable varieties, and any linking variety their predecessors is no longer an hypothesis, but between two forms is, of course, ranked as a distinct an historical fact; it is only the nature of the species, for the whole chain cannot be permanently physiological factors which is still open to disrestored. Thus the geological record is a history of cussion.'] the world indeed, but one imperfectly kept, and Geographical Distribution.—Neither the simi. written in a changing dialect; of this history we larity nor the dissimilarity of the inhabitants of possess the last volume only, relating to two or various regions, whether of land or sea, can be three countries. Even of this volume only here and accounted for by identity or differences of climate, there has a short chapter been preserved, and of or other physical conditions, but both are related in each page only here and there a few lines.
the most striking degree to the absence or presence Geological Succession of Organic Beings ( Distribu- of barriers to migration between those regions. tion in Time). --The preceding difficulties excepted, Within the same area there exists the most marked the facts of palæontology agree admirably with the affinity among the species, though these differ from theory. New species come in slowly and succes place to place. Species appear to have arisen in sively; they change in different rates and degrees; separate definite centres, the few apparent excepoll forms pass through rarity to extinction, and tions being accounted for by migration and disnever reappear ; dominant forms spread and vary, persal, followed by climatic and geographical their descendants displacing the inferior groups, so changes. But for a summary of our knowledge of tlat after long intervals of time the productions of the existing mode of distribution of organic life, the world appear to have changed simultaneously. and of the way in which that distribution has been The most ancient forms differ most widely from effected, as well as of the very important bearing of those now living, yet frequently present characters these facts upon the theory of evolution, which interinecliate between groups now widely divergent, they may be said, indeed, more than any other and they resemble to a "remarkable extent the class of 'facts, to have suggested, see the article embryos of the more recent and more highly GEOGRAPHICAL DISTRIBUTION. specialiserl animals belonging to the same classes. Morphological Arguments. The physiological These laws, and, above all, the important law of the and distributional lines of argument being, sum. succession of the same types within the same areas inarised, those furnished by morphology, although during the later geological periods, and most not less numerous and highly important, can only be notably between the Tertiary period and the very briefly outlined. These are mainly four, and present time (e.g. fossil and recent marsupials in are derived from (a) Classification, (6) Homologies, Australia, ani edentates in South America), cease (c) Embryology, (d) Rudimentary Organs. to be mysterious, and become at once thoroughly (a) Classification. Naturalists arrange the intelligible on the principle of inheritance, and on species, genera, and families in each class, on what that alone.
is called the Natural System. But what is meant [Since the publication of the Origin of Species in by this system? Is it, after all, merely an artificial 1859, paleontological research has been constantly scheme for enunciating general propositions, and of furnishing the most triumphant verification of these placing together the forms most like each other? views. The imperfection of the geological record or does it, as many believe, reveal the plan of crea.
far from overestimated that Huxley |tion ? The grand fact of classification is, that (Science and Culture, 1880), in comparing our organic beings, throughout all time, are arranged present knowledge of the mammalian Tertiary in groups subordinated under other groups-infauna with that of 1859, states that the results of dividuals under varieties, and these again under the investigations of Gaudry, Marsh, and Filhol species ; species under genera ; genera under subare as if zoologists were to become acquainted with families, families, and orders ; 'and all under a few a country hitherto unknown, as rich in novel forms grand classes. The nature of all these relation. of life as Brazil or South Africa once were to ships-the rules followed and the difficulties met
by naturalists in their classifications the high labelled specimens were lizards, birds, or mammals. value set upon constant and prevalent structures, This law of embryonic resemblance holds very whether these be of great or little use, or, as with widely—e.g. with young crustaceans. The embryo rudimentary organs, of none at all—the wide often retains within the egg or womb structures opposition in value between such misleading re which are of no service to it, either at that or at a semblances of adaptation, as, for instance, the fish- | later period of life, like the transitory gill-arches of like form of whales, and such characters of true birds or mammals; while, on the other hand, affinity as are afforded by the structure of their larvæ (e.g. of insects), which have to provide for circulatory or respiratory system-all these receive their own wants, undergo complete secondary a simple and natural explanation on the view of adaptation to the surrounding conditions. The the common descent of allied forms with modifica- process of development goes from the general to tion through variation and natural selection; while the special; thus there is generally an advance in it is to be noted that no other explanation has ever organisation. In peculiar conditions, however, even been attempted. The element of descent, degeneration may occur. All these facts are too, is already used in linking all the sexes, ages, readily explained on the principle of successive forms, and varieties of the same species, widely slight variations not necessarily or generally superthough these (e.g. Cirripedes ) may differ from each vening very early in life, and inherited at a correother in structure : and we have only to extend | sponding period; hence it is in the highest degree it to understand the meaning and origin of the probable that most embryonic stages show us more Natural System.
or less completely the progenitor of the group in its (6) Homology. The members of the same class, adult state ; and embryology thus rises greatly in independently of their habits of life, resemble each interest. See EMBRYOLOGY, other in their general plan of organisation. Thus, (d) Rudimentary Organs.-Rudimentary, atrothe hand of man, the digging-paw of the mole, the phied, and abortive organs, bearing the plain stamp leg of the horse, the paddle of the porpoise, and the of inutility, are so extremely common that it is imwing of the bat, are all constructed on the same possible to name a higher animal in which none pattern, bone corresponding to bone. Similarly
The mammæ of male mammals, the hindwith the hind-limb. Again, the mouths of insects legs of boas, the wings of many birds, or the teeth are of innumerable varieties of form and use of fætal whales, and the upper incisors of unborn witness the long spiral trunk of a moth, and the calves, are familiar instances. Such organs are ingreat jaws of a beetle--yet these are formed by ) telligible on the evolutionary theory, and on that modifications of an upper lip, mandibles, and two theory alone. pairs of maxillæ. And so it is with the limbs of Recapitulation and Conclusion. -After tersely crustaceans, or the flowers of plants; in fact, with summing up, the preceding mass of evidence, the organs of every class of beings.
Darwin concludes by pointing out (a) that the This conformity to type is powerfully suggestive theory of evolution by natural selection is no more of true relationship, of inheritance from a common inimical to religion than is that of gravitation, to ancestor ;' it admits, in short, as no one indeed which the same objection was strongly raised ; (6) denies, of a simple explanation in terms of the its revolutionary influence on the study of all deevolutionary theory, and thus strengthens that partments of natural history ; (c) on Psychology theory not a little. Attempts have been made to Tg.v.); (d) on the origin of man and his history explain this unity of plan in two other ways-first, (see MAN); (e) on our theories of future progress. by assuming it due to utility, which is negatived Envoy.— It is interesting to contemplate a by the facts, since organs of identical use (e.g. the tangled bank clothed with many plants of many wings of a bird and those of a butterfly) very | kinds, with birds singing on the bushes, with varifrequently do not conform to the same type at allo
; ous insects flitting about, and with worms crawling secondly, by attributing it to a unity of design, through the damp earth, and to reflect that these which, however, (a) instead of being always main elaborately constructed forms, so different from tained, as it should be, on the theory, is not un each other, and dependent on each other in so frequently quite lost in highly specialised forms; complex a manner, have all been produced by laws anit which, even if it always existed, (b) would acting around us. These laws, taken in the largest (lirectly suggest the unity of descent, the design sense, being Growth with Reproduction; and Inherthus serving only to mislead the anatomist. itance, which is almost implied by reproduction ;
Serial Homology, too, has to be accounted for- Variability from the indirect and direct action of that unity of type which is found on comparing the the conditions of life, and from use and disuse ; a different parts and organs in the same individual, Ratio of Increase so high as to lead to a Struggle so that the wonderfully complex and varied jaws for Life, and as a consequence to Natural Selecand legs of a lobster, or the widely different leaves, tion, entailing Divergence of Character and the sepals, petals, stamens, and pistils of a flower, are Extinction of less improved forms. Thus, from the all found to be modifications of a simple limb, and war of nature, from famine and death, the most a simple leaf-organ respectively. Not only are exalted object which we are capable of conceiving, such metamorphoses apparent on comparison, but namely, the production of the higher animals, they can be actually observed to occur during the directly follows. There is grandeur in this view of development of each individual ; is then the terin life, with its several powers, having been originally metamorphosis to have a mere metaphorical mean breathed by the Creator into a few forms, or into ing when applied to the species, or has it not one ; and that, whilst this planet has gone cycling actually arisen in past time, through the natural on according to the fixed law of gravity, from so selection and transmission of advantageous varia- simple a beginning endless forms most beautiful tions?
and most wonderful have been, and are being, (c) Development.-—It has been already indicated evolved. that the serially homologous parts in the same in The stormy reception of the Origin of Species, the dividual are alike during an early embryonic period, controversies to which it gave rise, its rapid as also are the homologous organs in animals which, and widespread acceptance, helped as it was by like bat, horse, and porpoise, may be willely differ- the independent support, yet generous self-abnegaentiated in adult life. So closely, too, do the tion, of Mr Wallace, and the powerful advocacy of embryos of the most distinct species belonging to Huxley, Hooker, Asa Gray, and others, are all the same class resemble each other, that even Von recorded in Darwin's Life. Of the proposed expan. Baer was unable to distinguish whether two un sion of the Origin, only the first chapter actually
appeared, as Variation of Animals and Plants mentioned Haeckel's Generelle Morphologie and Natural under Domestication (see VARIATION); but in History of Creation; Huxley's Lay Sermons, American Fertilisation of Orchids, Forms of Flowers, Insect | Addresses, Science and Culture, Anatomy of Invertebrated ivorous Plants, Climbing Plants, Movement in
Animals; also his essay On the Reception of the Origin Plants, we have a series which not only greatly of Species in Darwin's Life, vol. ii.; Obituary Notice of developed Darwin's favourite study of adaptations, Struggle for Existence, a Programme (Nineteenth Century, and with it enormously strengthened his general | 1888). Weismann's Studies in the Theory of Descent theory; but gave to the arid field of botany the | (1886-82), and for more recent developments his subseinterest and freshness of a new intellectual spring quent papers (see HEREDITY, REPRODUCTION), must also (see BOTANY). Again, the very difficulties which be noted. Romanes' Scientific Evidences of Organic he felt to be presented to his theory by the com Evolution, Lankester's Degeneration (both Nature plex phenomena of bee and ant society led him series), Schmidt's Doctrine of Descent and Darwinism, onwards, till he reached the problems of mind and
Fiske's Darwinism and other Essays, are examples in language; the obvious and burning question of the English of an abundant and more popular literature, in origin of man had also to be faced, and thus we
which the writings of Mr Grant Alen and Dr A. Wilson had the Descent of Man and the Expression of the
are also specially known, and which is likewise abundant
in Germany, France, and Italy. Emotions.
Of controversial writings may be cited Mivart's Genesis Before conclusion, justice demands, if not dis of Species, Lessons from Nature, &c.; the Duke of Argyll's cussion, at least mention of some of the more im Unity of Nature, as well as the review articles of both portant criticisms which have been urged against writers. See also Butler's Evolution, Old and New, and Darwin's theory. That which Darwin himself Luck or Cunning. For the literature of the more conseems to have felt as most serious was made by structive attempts referred to, see EVOLUTION. For Fleeming Jenkin, who laid stress on the tendency general bibliography Bettany's Life of Darwin is most to swamping any individual variation, however accessible; while complete help will be obtained from advantageous, tlırough intercrossing. Mr Mivart's Seidlitz, Die Darw. Theorie Leip. 1875), and from
the Naples Jahresbericht f. Zoologie; preferably, howGenesis of Species next engaged him most; but
ever, since 1886 from the Zoological Record. Darwin's replies to these and other criticisms up to 1872 will be found in the final edition of the Origin
Darwin Sound and MOUNT DARWIN are on of Species. In his essay in Darwin's Life, Huxley the SW. side of King Charles's South Land, Tierra says, 'I venture to affirm that so far as all my del Fuego. The mountain rises 6800 feet. knowledge goes, all the ingenuity and all the
Dasent, SIR GEORGE WERBE, was born in 1820 learning of hostile critics have not enabled them to
at St Vincent in the West Indies, of which island adduce a single fact of which it can be said this is
his father was attorney-general. He was educated irreconcilable with the Darwinian theory ;' while
at Westminster School and King's College, London; Mr Ray Lankester still more recently assures us graduated B.A. at Magdalen College, Oxford, in that since its first publication in 1859 the history 1840; and was called to the bar at the Middle of Darwin's theory has been one of continuous and Temple in 1852, in which year also he received his decisive conquest, so that at the present day it is degree of D.C.L. He acted some years as an universally accepted as the central, all-embracing assistant-editor in the Times office, and married doctrine of zoological and botanical science.'
a sister of its editor, Mr Delane. An accomAs a matter of fact, however, this universal plished linguist
, he had often acted as examiner in acceptance' is not without its universally dis- | English and modern languages for civil service tributed exceptions. Some of Darwin's contem
appointments, when he was appointed a Civil poraries have withheld their adhesion-e... Virchow Service Commissioner in 1870, and knighted for in Germany, Owen and Cleland in Britain, public services' in 1876. Already in 1842 he puband the older French naturalists; nor can the
fished a translation of The Prose or Younger Edda; critical and controversial writings of Mivart, the
which was followed by an essay, 'The Norsemen, Duke of Argyll, Samuel Butler, and others, be thus wholly ignored. Constructive criticism is also the Norse, with an introductory Essay on the Origin
in the Oxford Essays (1858); Popular Tales from busy. On one hand certainly we have the ultraDarwinian speculations of Weismann, warmly from the Fjeld (1874), both from the Norwegian of
and Diffusion of Popular Tales (1859), and Tales accepted by Lankester and others; but on the Asbjörnsen ; translations from the Icelandic of the other, attempts are again being made, and with Saga of Burnt Njal (1861), and the Story of Gisli, increasing frequency, to restate the theory of evolu
the Outlaw (1866); and an Introduction and Life tion more or less completely in non-Darwinian
of Cleasby, prefixed to Vigfusson's completion of terms. Thus, following up the doubt which occa
Cleasby's unfinished Icelandic-English Dictionary sionally troubled Mr Darwin's recent years, that he
(1874). Sir George Dasent has also written several had assigned too little importance to the modifying fair novels. His famous introduction to Asbjörnfactors of use and disuse, of environment, &c., we
sen's Popular Tales was a solid contribution to have Mr Spencer re-entering the field ; in America folklore, being an admirable exposition of the an active Neo-Lamarckian school has also arisen, Aryan theory of story-transmission as advocated which lacks neither knowledge nor thoughtfulness ; | by Grimm and Max Müller. in Germany we owe new constructive efforts to Nägeli and Semper, and more recently to Eimer ; Dash, COUNTESS, the name under which while in Britain, complementary hypotheses have Gabrielle Anna Cisterne de Courtiras, Vicomtesse been propounded by Romanes, Sutton, Gulick, de Saint-Mars, published a series of novels, many Geddes, &c. But such proposed positive contribu- of which were readable, if of but slender literary tions to the evolutionary theory fall rather to be merit. She was born at Poitiers, August 2, 1804, treated under EVOLUTION.
of a noble family, married early, and took to
literature for a living after the loss of her proSee BIOLOGY, BOTANY, EVOLUTION, ENVIRONMENT, perty, writing sometimes as many as five or six HEREDITY, GEOGRAPHICAL DISTRIBUTION, ZOOLOGY, and
novels a year, other articles. Besides the works of Darwin himself,
She died 11th September 1872. and those of Alfred Russell Wallace (from Natural Selec
Her stories deal almost exclusively with the aristotion in 1870 to Darwinism in 1889), with the special cratic world and its more or less illegitimate liaitreatises referred to under the above-mentioned and
sons. They have a certain brightness and vigour, minor articles (e.g. FERTILISATION), see F. Darwin's Life but lack reality, and are peopled by a crowd of of Charles Darwin.; also minor Lives by Grant Allen stilted puppets rather than living men and women, and Bettany. Of other expository literature may be of her numberless books may only be mentioned