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Fifth Sixth

Edition. Edition. Chief Additions and Corrections.
Page Page
231 140 The account of the electric organ of fishes added to.
233 142 Analogical resemblance between the eyes of Cephalopods and
Vertebrates.
234 143 Claparede on the analogical resemblance of the hair-claspers
of the Acaridae.
248 152 The probable use of the rattle to the Rattle-snake.
248 152 | Helmholtz on the imperfection of the human eye.
255 156 The first part of this new chapter consists of portions, in a
much modified state, taken from chap. iv. of the former
editions. The latter and larger part is new, and relates
chiefly to the supposed incompetency of natural selection
to account for }. incipient stages of useful structures.
There is also a discussion on the causes which prevent in
many cases the acquisition through natural selection of
useful structures. Lastly, reasons are given for disbelieving
in great and sudden modifications. Gradations of character,
often accompanied by changes of function, are likewise
here incidentally considered.
268 200 The statement with respect to young cuckoos ejecting their
foster-brothers confirmed.
270 200 || On the cuckoo-like habits of the Molothrus.
307 224 On fertile hybrid moths.
319 232 The discussion on the fertility of hybrids not having been
acquired through natural selection condensed and modified.
326 235 | On the causes of sterility of hybrids, added to and corrected.
377 267 | Pyrgoma found in the chalk.
402 283 || Extinct forms serving to connect existing groups.
440 || 308 Qn earth adhering to the feet of migratory birds.
463 322 || On the wide geographical range of a species of Galaxias, a
fresh-water fish.
505 || 350 | Discussion on analogical resemblances, enlarged and modified.
316 358 || Homological structure of the feet of certain marsupial animals.
518 361 On serial homologies, corrected.
520 362 Mr. E. Ray Lankester on morphology.
521 363 On the asexual reproduction of Chironomus.
541 377 On the origin of rudimentary parts, corrected.
547 381 | Recapitulation on the sterility of hybrids, corrected.
552 384 Recapitulation on the absence of fossils beneath the Cam-
brian system, corrected.
568 395 | Natural selection not the exclusive agency in the modification
of species, as always maintained in this work.
572 398 || The belief in the separate creation of species generally held

by naturalists, until a recent period.

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AN HISTORICAL SKETCH OF THE PROGRESS OF OPINION ON THE ORIGIN of SPECIES,

PREVIOUSLY TO THE PUBLICATION OF THE FIRST EDITION
OF THIS Work.

I will here give a brief sketch of the progress of opinion on the Origin of Species. Until recently the great majority of naturalists believed that species were immutable productions, and had been separately created. This view has been ably maintained by many authors. Some few naturalists, on the other hand, have believed that species undergo modification, and that the existing forms of life are the descendants by true generation of pre-existing forms. Passing over allusions to the subject in the classical writers,” the first author who in modern times has treated it in a scientific spirit was Buffon. But as his opinions fluctuated greatly at different periods, and as he does not enter on the causes or means of the transformation of species, I need not here enter on details. Lamarck was the first man whose conclusions on the subject excited much attention. This justly-celebrated naturalist first

* Aristotle, in his “Physicae Auscultationes' (lib. 2, cap. 8, s. 2), after remarking that rain does not fall in order to make the corn grow, any more than it falls to spoil the farmer's corn when threshed out of doors, applies the same argument to organisation; and adds (as translated by Mr. Clair Grece, who first pointed out the passage to me), “So what hinders the different parts [of the body] from having this merely accidental relation in nature; as the teeth, for example, grow by necessity, the front ones sharp, adapted for dividing, and the grinders flat, and . for masticating the food; since they were not made for the sake of this, but it was the result of accident. And in like manner as to the other parts in which there appears to exist an adaptation to an end. Wheresoever, therefore, all things together (that is all the parts of one whole) happened like as if they were made for the sake of something, these were preserved, having been appropriately constituted by an internal spontaneity; and whatsoever things were not thus constituted, perished, and still erish.” We here see the principle of natural selection shadowed forth, but ow little Aristotle fully comprehended the principle, is shown by his remarks on the formation of the teeth.

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published his views in 1801; he much enlarged them in 1809 in his “Philosophie Zoologique, and subsequently, in 1815, in the Introduction to his ‘Hist. Nat, des Animaux sans Vertèbres. In these works he upholds the doctrine that species, including man, are descended from other species. He first did the eminent service of arousing attention to the probability of all change in the organic, as well as in the inorganic world, being the result of law, and not of miraculous interposition. Lamarck seems to have been chiefly led to his conclusion on the gradual change of species, by the difficulty of distinguishing species and varieties, by the almost perfect gradation of forms in certain groups, and by the analogy of domestic productions. With respect to the means of modification, he attributed something to the direct action of the physical conditions of life, something to the crossing of already existing forms, and much to use and disuse, that is, to the effects of habit. To this latter agency he seems to attribute all the beautiful adaptations in nature;—such as the long neck of the giraffe for browsing on the branches of trees. But he likewise believed in a law of progressive development; and as all the forms of life thus tend to progress, in order to account for the existence at the present day of simple productions, he maintains that such forms are now spontaneously generated.” Geoffroy Saint-Hilaire, as is stated in his ‘Life,' written by his son, suspected, as early as 1795, that what we call species are various degenerations of the same type. It was not until 1828 that he published his conviction that the same forms have not been perpetuated since the origin of all things. Geoffroy seems to have relied chiefly on the conditions of life, or the “monde ambiant” as the cause of change. He was cautious in drawing conclusions, and did not believe that existing species are now undergoing modification; and, as his son adds, “C'est done un problème a réserver

* I have taken the date of the first publication of Lamarck from Isid. Geoffroy Saint-Hilaire's (“Hist, Nat, Générale,' tom. ii. p. 405, 1859) excellent history of opinion on this subject. In this work a full account is given of Buffon's conclusions on the same subject. It is curious how largely my grandfather, Dr. Erasmus Darwin, anticipated the views and erroneous grounds of opinion of Lamarck in his ‘Zoonomia' (vol. i. pp. 500–510), published in 1794. According to Isid. Geoffroy there is no doubt that Goethe was an extreme partisan of similar views, as shown in the Introduction to a work written, in 1794 and 1795, but not published till long afterwards: he has pointedly remarked (“Goethe als. Naturforscher, von Dr. Karl Meding, s. 34) that the future question for naturalists will be how, for instance, cattle got their horns, and not for what they are used. It is rather a singular instance of the manner in which similar views arise at about the same time, that Goethe in Germany, Dr. Darwin in England, and Geoffroy Saint-Hilaire (as we shall

immediately see) in France, came to the same conclusion on the origin of species, in the years 1794–5. c

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entièrement à l'avenir, supposé méme que l'avenir doive avoir prise sur lui.” In 1813 Dr. W. C. Wells read before the Royal Society “An Account of a White female, part of whose skin resembles that of a Negro'; but his paper was not published until his famous ‘Two Essays upon Dew and Single Vision’ appeared in 1818. In this paper he distinctly recognises the principle of natural selection, and this is the first recognition which has been indicated; but he applies it only to the races of man, and to certain characters alone. After remarking that negroes and mulattoes enjoy an immunity from certain tropical diseases, he observes, firstly, that all animals tend to vary in some degree, and, secondly, that agriculturists improve their domesticated animals by selection; and then, he adds, but what is done in this latter case “by art, seems to be done with equal efficacy, though more slowly, by nature, in the formation of varieties of mankind, fitted for the country which they inhabit. Of the accidental varieties of man, which would occur among the first few and scattered inhabitants of the middle regions of Africa, some one would be better fitted than the others to bear the diseases of the country. This race would consequently multiply, while the others would decrease; not only from their inability to sustain the attacks of disease, but from their incapacity of contending with their more vigorous neighbours. The colour of this vigorous race I take for granted, from what has been already said, would be dark. But the same disposition to form varieties still existing, a darker and a darker race would in the course of time occur: and as the darkest would be the best fitted for the climate, this would at length become the most prevalent, if not the only race, in the particular country in which it had originated.” He then extends these same views to the white inhabitants of colder climates. I am indebted to Mr. Rowley, of the United States, for having called my attention, through Mr. Brace, to the above passage in Dr. Wells' work. The Hon. and Rev. W. Herbert, afterwards Dean of Manchester, in the fourth volume of the ‘Horticultural Transactions,’ 1822, and in his work on the “Amaryllidaceae' (1837, pp. 19, 339), declares that “horticultural experiments have established, beyond the possibility of refutation, that botanical species are only a higher and more permanent class of varieties.” He extends the same view to animals. The Dean believes that single species of each genus were created in an originally highly plastic condition, and that these have produced, chiefly by intercrossing, but likewise by variation, all our existing species. In 1826 Professor Grant, in the concluding paragraph in his well-known paper (“Edinburgh Philosophical Journal, vol. xiv. p.283) on the Spongilla, clearly declares his belief that species are

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