Search Results - The Complete Work of Charles Darwin Online

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

-brown apex of the fore wing in Limenitis lorquini would be demonstrated by a glance at its average condition in specimens from the different localities as we pass from north to south. Furthermore, we might reasonably hope that a similar series collected after an interval not greatly prolonged would exhibit differences in average composition—the actual measurable evidence of the evolution of a character in a species in the natural state. Even though such evidence be left for our successors to

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

far the species of the same genus differ in the ocelli. As I know from your Orchid Drawings how skilful an artist you are, perhaps it would not give you much more trouble to sketch any variable ocelli than to describe them.—I am very much obliged to you for so kindly assisting 1 For a further account of this and other uses of these markings, together with references to the Original memoirs, see' eye-spots' in index of Essays on Evolution (1908), 424. [page] 233 EYE-SPOTS ON BUTTERFLIES' WINGS: 186

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

females.3 My friend Mr. Harry Eltringham has recently pointed out to me a passage, marked by much confusion of thought, in Hewitson's Exotic Butterflies, which might be read as an anticipation 1 See' dardanus' in index of Essays on Evolution (1908), 414; also Plate XXIII in Trans. Ent. Soc. Lond. (1908 J, 427-45. 2 Trans. Ent. Soc. Lond. (1874!, 137. 3 E. M. M. (Oct., 1874), 113. 4 London, 1862-66, III: text of plate' Nymphalidæ. Diadema iii.: (pages unnumbered). [page] 238 DARWIN'S LETTERS TO R

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

possible to give the strongest cases opposed to me, and often such conjectures as occur to me.'2 1856, July 19.—'it is absolutely necessary that I should discuss single and double creations, as a very crucial point on the general Origin of species, and I must confess, with the aid of all sorts of visionary hypotheses, a very hostile one.'3 The above-quoted sentences sum up very briefly Darwin's conclusion that evolution as he conceived of it implied that each species had appeared once only in a

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

time refuting the opinion-not uncommon even at the present day-that a terrestrial species such as man may exist on Mars or on some other body outside the earth. For Darwin shows in the following letter that, in order to produce the same species twice over, the same material must have been subject to the same selection at every stage, right back to the unknown starting-point of organic evolution. 'As far as I can judge, the improbability is extreme that the same well-characterised species should

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

assistance. The extent of this unintentional, but very serious, misrepresentation of an authority by his exponent, can be most clearly shown by printing together passages by de Vries and Bateson from 1 'Of the inheritance of mutations there is no doubt. Of the transmission of fluctuations there is no very strong evidence. It is therefore reasonable to regard the mutation as the main, if not the only, basis of evolution.'(p. 72.) 2 Mendel's Principles of Heredity, Cambridge (1909), 287. 3 Species

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

he has termed fluctuating.'2 In order to ensure an accurate recognition it will be safest to quote de Vries's words. (1) In the celebrated Mutationstheorie (Leipzig, 1901, I.) de Vries states that, in advocating the use of the term' fluctuation', he is merely adopting a word often used by Darwin himself.3 Thus, 1 Variation, Heredity and Evolution, London, 1909, 2nd Ed., 155. See also passage (1) quoted from Mr. Lock on p. 270. 2 Mendelism, R. C. Punnett, 2nd Ed., Cambr. (1907), 70. 3 An

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

hypothesis of the direct influence of environment as a motive cause of evolution:— 'In regard to thorns and spines I suppose that stunted and (illegible) hardened processes were primarily left by the abortion of various appendages, but 1 must believe that their extreme sharpness and hardness is the result of fluctuating variability and the survival of the fittest . 'In a letter to G. H. Lewes, Aug. 7, 1868. More Letters, i. 308. 1 De Vries is here referring to p. 29, where he distinguishes the two

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

. * 'From his own experiments, de Vries has come to the conclusion that, when selection is really efficient, the full possible effect of this process is exhausted in quite a small 1 Fifty Years of Darwinism, New York (1909), 173-4. 2 Variation, Heredity and Evolution. London, 1909. Second Ed. [page] 271 OTHER WRITERS ON 'FLUCTUATIONS

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A331 Book: Poulton, Edward Bagnall. 1909. Charles Darwin and the Origin of species: addresses, etc., in America and England in the year of the two anniversaries. London: Longmans, Green, and Co. Text Image

'fluctuations' are assumed by him to be transmissible by heredity, and that this assumption is an essential element in the author's definition of his technical term. When we remember that they are just the 'Individual differences' of Darwin, and that de Vries's belief in their powerlessness for continued evolution is based on Francis Galton's well-known law of recession, it is really waste of time to inquire whether they are transmissible. But such positive statements to the contrary have been made by

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A35 Pamphlet: Shipley, A.E. [1909]. Charles Darwin. [Cambridge, Privately Printed]. Text Image

being, modified as time goes on. This is the fate of all scientific theories; none are stationary, none are final. The development of Science is a continuous process of evolution, like the world of phenomena itself. It has however some few landmarks which stand out exceptional and prominent. None of these is greater or will be more enduring in the history of thought than the theory associated with the name of Charles Darwin. I cannot attempt further to weigh or estimate the influence and the

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A36 Periodical contribution: Darwin Centenary Number. Christ's College Magazine. vol. XXIII, Easter Term, 1909. Text Image PDF

Law that has regulated the Introduction of New Species (Ann. and Mag. Nat. Hist., 1855). The Law is Every species has come into existence coincident both in space and time with a pre-existing closely allied species. Mr Wallace remarks (My Life, Vol. 1. p. 335) This clearly pointed to some kind of evolution but the how was still a secret. Mr Huxley has said of this powerful essay : On reading it afresh I have been astonished to recollect how small was the impression it made. (Life and Letters of

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A36 Periodical contribution: Darwin Centenary Number. Christ's College Magazine. vol. XXIII, Easter Term, 1909. Text Image PDF

migratory bird might carry them great distances. 2 In the Origin however he made it plain that Man was included in his scheme of evolution. [page] 22

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A36 Periodical contribution: Darwin Centenary Number. Christ's College Magazine. vol. XXIII, Easter Term, 1909. Text Image PDF

of the means by which evolution has taken place in the organic world, the theory of Natural Selection which he published contemporaneously with Mr A. R. Wallace in 1858, and set forth with a wealth of illustration and argument in The Origin of Species in the following year. Now although at the present time we are all evolutionists we hear it frequently said that Darwinism has had its day, and that Natural Selection is insufficient to account for the facts. It is true that very many of the

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A36 Periodical contribution: Darwin Centenary Number. Christ's College Magazine. vol. XXIII, Easter Term, 1909. Text Image PDF

England during the last half-century. Here we see evolution taking place in Nature, but as to the usefulness of the dark forms we can only guess. But it is possible that while the change of colour is useless in itself, it is associated with increased constitutional vigour or some other advantage of the kind, and that it is the associated improvement which has caused the varieties to increase, not the colour-change itself. This leads us on to the third, and perhaps the most frequent objection in

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A36 Periodical contribution: Darwin Centenary Number. Christ's College Magazine. vol. XXIII, Easter Term, 1909. Text Image PDF

, many of the facts chronicled by Darwin many be said, in a certain sense, to have been the starting points of subsequent investigations, e.g. on such questions as wool production and fertility, the solutions of which are of the utmost importance to the stock raiser and practical agriculturist. In the second volume of the Animals and Plants, Darwin discusses the phenomena of inheritance, the effects of crossing and of inbreeding, and the nature of hybridism. The conception of evolution by

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A36 Periodical contribution: Darwin Centenary Number. Christ's College Magazine. vol. XXIII, Easter Term, 1909. Text Image PDF

notice. But even now it cannot be contended that the Mendelian investigations, vastly important though these be to the student of heredity and the experimental breeder, have contributed much, at any rate as yet, towards the elucidation of the central problem which Darwin set out to solve, namely, the origin of species. It has recently been observed that although the evolution theory exerted so great an influence upon anatomy and kindred branches of biology, the science of physiology has always

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

shortcomings in the correction of proofs. The two portraits of Darwin are reproduced by permission of Messrs Maull and Fox and Messrs Elliott and Fry. The photogravure of the study at Down is reproduced from an etching by Mr Axel Haig, lent by Mr Francis Darwin; the coloured plate illustrating Prof. Weismann's essay was originally published by him in his Vortr ge ber Descendenztheorie which afterwards appeared (1904) in English under the title The Evolution Theory. Copies of this plate were

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

, Darwin just 1 See in particular Samuel Butler, Evolution Old and New, London, 1879; J. L. de Lanessan, Buffon et Darwin , Revue Scientifique, XLIII. pp. 385-391, 425-432, 1889. 2 op. cit. p. 136. 3 See Ernst Krause and Charles Darwin, Erasmus Darwin, London, 1879. [page] 1

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

III THE SELECTION THEORY BY AUGUST WEISMANN. Professor of Zoology in the University of Freiburg (Baden). I. THE IDEA OF SELECTION. MANY and diverse were the discoveries made by Charles Darwin in the course of a long and strenuous life, but none of them has had so far-reaching an influence on the science and thought of his time as the theory of selection. I do not believe that the theory of evolution would have made its way so easily and so quickly after Darwin took up the cudgels in favour of