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descended from other species, and that they become improved in the course of modification. This same view was given in his 55th Lecture, published in the ‘Lancet' in 1834. In 1831 Mr. Patrick Matthew published his work on ‘Naval Timber and Arboriculture, in which he gives precisely the same view on the origin of species as that (presently to be alluded to) propounded by Mr. Wallace and myself in the ‘Linnean Journal,' and as that enlarged in the present volume. Unfortunately the view was given by Mr. Matthew very briefly in scattered passages in an Appendix to a work on a different subject, so that it remained unnoticed until Mr. Matthew himself drew attention to it in the ‘Gardener's Chronicle, on April 7th, 1860. The differences of Mr. Matthew's view from mine are not of much importance: he seems to consider that the world was nearly depopulated at successive periods, and then re-stocked; and he gives as an alternative, that new forms may be generated “without the presence of any mould or germ of former aggregates.” I am not sure that I understand some passages; but it seems that he attributes much influence to the direct action of the conditions of life. He clearly saw, however, the full force of the principle of natural selection. The celebrated geologist and naturalist, Von Buch, in his excellent ‘Description Physique des Isles Canaries’ (1836, p. 147), clearly expresses his belief that varieties slowly become changed into permanent species, which are no longer capable of intercrossing. Rafinesque, in his ‘New Flora of North America, published in 1836, wrote (p. 6) as follows:– “All species might have been Varieties once, and many varieties are gradually becoming species by assuming constant and peculiar characters;” but farther on (p. 18) he adds, “except the original types or ancestors of the genus.” In 1843–44 Professor Haldeman (‘Boston Journal of Nat. Hist, U. States, vol. iv. p. 468) has ably given the arguments for and against the hypothesis of the development and modification of species; he seems to lean towards the side of change. The “Vestiges of Creation' appeared in 1844. In the tenth and *h improved edition (1853)the anonymous author says(p.155):The proposition determined on after much consideration is, that the several series of animated beings, from the simplest and oldest op to the highest and most recent, are, under the providence of God, the results, first, of an impulse which has been imparted to the forms of life, advancing them, in definite times, by generation, through grades of organisation terminating in the highest dicotyledons and vertebrata, these grades being few in number, and generally marked by intervals of organic character, which we find to be a practical difficulty in ascertaining affinities; second, of another impulse connected with the vital forces, tending, in the course of generations, to modify organic structures in accordance with external circumstances, as food, the nature of the habitat, and the meteoric agencies, these being the “adaptations’ of the natural theologian.” The author apparently believes that organisation progresses by sudden leaps, but that the effects produced by the conditions of life are gradual. He argues with much force on general grounds that species are not immutable productions. But I cannot see how the two supposed “impulses” account in a scientific sense for the numerous and beautiful co-adaptations which we see throughout nature; I cannot see that we thus gain any insight how, for instance, a woodpecker has become adapted to its peculiar habits of life. The work, from its powerful and brilliant style, though displaying in the earlier editions little accurate knowledge and a great want of scientific caution, immediately had a very wide circulation. In my opinion it has done excellent service in this country in calling attention to the subject, in removing prejudice, and in thus preparing the ground for the reception of analogous views. In 1846 the veteran geologist M. J. d'Omalius d'Halloy published in an excellent though short paper (“Bulletins de l'Acad. Roy Bruxelles, tom. xiii. p. 581) his opinion that it is more probable that new species have been produced by descent with modification than that they have been separately created: the author first promulgated this opinion in 1831. Professor Owen, in 1849 (‘Nature of Limbs, p. 86), wrote as follows:– “The archetypal idea was manifested in the flesh under diverse such modifications, upon this planet, long prior to the existence of those animal species that actually exemplify it. To what natural laws or secondary causes the orderly succession and progression of such organic phenomena may have been committed, we, as yet, are ignorant.” In his Address to the British Association, in 1858, he speaks (p. li.) of “the axiom of the continuous operation of creative power, or of the ordained becoming of living things.” Farther on (p. x.c.), after referring to geographical distribution, he adds, “These phenomena shake our confidence in the conclusion that the Apteryx of New Zealand and the Red Grouse of England were distinct creations in and for those islands respectively. Always, also, it may be well to bear in mind that by the word ‘creation’ the zoologist means ‘a process he knows not what.” He amplifies this idea by adding that when such cases as that of the Red Grouse are “enumerated by the zoologist as evidence of distinct creation of the bird in and for such islands, he chiefly expresses that he knows not how the Red Grouse came to be there, and there exclusively; signifying also, by this mode of expressing such ignorance, his belief that both the bird and the islands owed their origin to a great first Creative Cause.” If we interpret these sentences given in the same Address, one by the other, it appears that this eminent philosopher felt in 1858 his confidence shaken that the Apteryx and the Red Grouse first appeared in their respective homes, “he knew not how,” or by some process “he knew not what.” This Address was delivered after the papers by Mr. Wallace and myself on the Origin of Species, presently to be referred to, had been read before the Linnean Society. When the first edition of this work was published, I was so completely deceived, as were many others, by such expressions as “the continuous operation of creative power,” that I included Professor Owen with other palaeontologists as being firmly convinced of the immutability of species; but it appears (“Anat, of Vertebrates, vol. iii. p. 796) that this was on my part a preposterous error. In the last edition of this work I inferred, and the inference still seems to me perfectly just, from a passage beginning with the words “no doubt the type-form,” &c. (Ibid. vol. i. p. xxxv.), that Professor Owen admitted that natural selection may have done something in the formation of a new species; but this it appears (Ibid. vol. iii. p. 798) is inaccurate and without evidence. I also gave some extracts from a correspondence between Professor Owen and the Editor of the ‘London Review,’ from which it appeared manifest to the Editor as well as to myself, that Professor Owen claimed to have promulgated the theory of natural selection before I had done so; and I expressed my surprise and satisfaction at this announcement; but as far as it is possible to understand certain recently published passages (Ibid. vol. iii. p. 798) I have either partially or wholly again fallen into error. It is consolatory to me that others find Professor Owen's controversial writings as difficult to understand and to reconcile with each other, as I do. As far as the mere enunciation of the principle of natural selection is concerned, it is quite immaterial whether or not Professor Owen preceded me, for both of us, as shown in this historical sketch, were long ago preceded by Dr. Wells and Mr. Matthews. M. Isidore Geoffroy Saint-Hilaire, in his lectures delivered in 1850 (of which a Résumé appeared in the ‘Revue et Mag. de Zoolog., Jan. 1851), briefly gives his reason for believing that specific characters “sont fixás, pour chaque espèce, tant qu’elle se perpétue au milieu des mémes circonstances: ils se modifient, si les circonstances ambiantes viennent a changer.” “En résumé, l'observation des animaux sauvages démontre déjà la variabilité limitée des espèces. Les expériences sur les animaux sauvages devenus domestiques, et sur les animaux domestiques redevenus sauvages, la démontrent plus clairement encore. Ces mêmes expériences prouvent, de plus, que les différences produites peuvent

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étre de valeur générique.” In his ‘Hist. Nat. Générale’ (tom. ii. p. 430, 1859) he amplifies analogous conclusions.

From a circular lately issued it appears that Dr. Freke, in 1851 (“Dublin Medical Press, p. 322), propounded the doctrine that all organic beings have descended from one primordial form. His grounds of belief and treatment of the subject are wholly different from mine; but as Dr. Freke has now (1861) published his Essay on the “Origin of Species by means of Organic Affinity, the difficult attempt to give any idea of his views would be superfluous on my part.

Mr. Herbert Spencer, in an Essay (originally published in the “Leader, March, 1852, and republished in his ‘Essays,’ in 1858), has contrasted the theories of the Creation and the Development of organic beings with remarkable skill and force. He argues from the analogy of domestic productions, from the changes which the embryos of many species undergo, from the difficulty of distinguishing species and varieties, and from the principle of general gradation, that species have been modified; and he attributes the modification to the change of circumstances. The author (1855) has also treated Psychology on the principle of the necessary acquirement of each mental power and capacity by gradation.

In 1852 M. Naudin, a distinguished botanist, expressly stated, in an admirable paper on the Origin of Species (‘Revue Horticole, p. 102; since partly republished in the ‘Nouvelles Archives du Muséum, tom. i. p. 171), his belief that species are formed in an analogous manner as varieties are under cultivation; and the latter process he attributes to man's power of selection. But he does not show how selection acts under nature. He believes, like Dean Herbert, that species, when nascent, were more plastic than at present. He lays weight on what he calls the principle of finality, “puissance mystérieuse, indéterminée; fatalité pour les uns; pour les autres, volonté providentielle, dont l'action incessante sur les étres vivants détermine, a toutes les époques de l'existence du monde, la forme, le volume, et la durée de chacun d'eux, en raison desa destinée dans l'ordre de choses dontil fait partie. C'est cette puissance qui harmonise chaque membre a l'ensemble, en l'appropriant à la fonction qu'il doit remplir dans lorganisme général de lanature, fonction quiest pour luisa raison d'être.” +

* From references in Bronn's Untersuchungen über die EntwickelungsGesetze, it appears that the celebrated botanist and palaeontologist Unger published, in 1852, his belief that species undergo development and modification. Dalton, likewise, in Pander and Dalton's work on Fossil Sloths, exressed, in 1821, a similar belief. Similar views have, as is well known, n maintained by Oken in his mystical ‘Natur-Philosophie.” From other

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In 1853 a celebrated geologist, Count Keyserling (‘Bulletin de la Soc. Géolog., 2nd Ser, tom. x. p. 357), suggested that as new diseases, supposed to have been caused by some miasma, have arisen and spread over the world, so at certain periods the germs of existing species may have been chemically affected by circumambient molecules of a particular nature, and thus have given rise to new forms. In this same year, 1853, Dr. Schaaffhausen published an excellent pamphlet (“Verhand, des Naturhist. Vereins der Preuss. Rheinlands,’ &c.), in which he maintains the development of organic forms on the earth. He infers that many species have kept true for long periods, whereas a few have become modified. The distinction of species he explains by the destruction of intermediate graduated forms. “Thus living plants and animals are not separated from the extinct by new creations, but are to be regarded as their descendants through continued reproduction.” A well-known French botanist, M. Lecoq, writes in 1854 (‘Etudes sur Géograph. Bot.,’ tom. i. p. 250), “On voit que nos recherches sur la fixité ou la variation de l'espèce, mous conduisent directement auxidées émises, par deux hommes justement célèbres, Geoffroy Saint-Hilaire et Goethe.” Some other passages scattered through M. Lecoq's large work, make it a little doubtful how far he extends his views on the modification of species. The ‘Philosophy of Creation’ has been treated in a masterly manner by the Rev. Baden Powell, in his ‘Essays on the Unity of Worlds,’ 1855. Nothing can be more striking than the manner in which he shows that the introduction of new species is “a regular, not a casual phenomenon,” or, as Sir John Herschel expresses it, “a natural in contradistinction to a miraculous process.” The third volume of the ‘Journal of the Linnean Society’ contains papers, read July 1st, 1858, by Mr. Wallace and myself, in which, as stated in the introductory remarks to this volume, the theory of Natural Selection is promulgated by Mr. Wallace with admirable force and clearness. Von Baer, towards whom all zoologists feel so profound a respect, expressed about the year 1859 (see Prof. Rudolph Wagner, “Zoologisch-Anthropologische Untersuchungen,’ 1861, s. 51) his conviction, chiefly grounded on the laws of geographical distribu

references in Godron's work, ‘Sur l'Espèce,” it seems that Bory St. Vincent, Burdach, Poirot, and Fries, have all admitted that new species are continually being produced.

Ima add, that of the thirty-four authors named in this Historical Sketch, who believe in the modification of species, or at least disbelieve in separate acts of creation, twenty-seven have written on special branches of natural history or geology,

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