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A297
Book:
Darwin, Francis & E. Hamilton Acton. 1909. Practical physiology of plants. Cambridge: University Press.
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CH. X] NITRATES. 253 allowed to stand (preferably in vacuo over sulphuric acid), characteristic crystals of copper oxide compound of amide may be obtained. (2) A well-cooled mixture of potassium nitrite and dilute sulphuric acid. Amides evolve nitrogen. (3) Boiling for some time with dilute acid. Amides give ammonia in solution which can be tested for in the usual ways, best by heating with excess of magnesia and testing for evolution of the gas. Ammonia, Nitrates, Nitrites, may be tested for
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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.
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brief account of the history which led up to and followed the publication of the theory of Natural Selection and the Origin of Species. Darwin's sure scientific insight, and his views on evolution by mutation, briefly treated in this Section, receive further consideration in Appendices A and B. The confusion of thought threatened by the unintentional but most unfortunate misrepresentation of de Vries's term, 'fluctuating variability,' is pointed out in a footnote and further considered in Appendix
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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.
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how Darwinism can account for the valuable mechanical functions of lifeless structures. 1 And even more arresting is the contrast between Darwin's outlook on the world of life and that of the eminent Dutch botanist who raised fresh strains, or perhaps sorted over again old mixtures of Evening Primroses, and straightway said to his friends: 'Go to, let us build us an exalted theory of evolution based on the conception of an inborn transforming force violently discharged at regular intervals by
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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.
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extraordinary and, - as many naturalists think,—the unwarrantable exaggeration of the importance of the Dutch botanist's contributions to evolution. Omne ignotum pro magnifico. If de Vries had indeed proved, as his exponents assert, that the 'Individual differences' in which Darwin saw the steps of evolutionary progress—the 'Individual differences' whose behaviour in heredity is the lifework of Francis Galton—that these are in fact nontransmissible to offspring, then surely the greatness of
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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.
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AT OXFORD (Feb. 12, 1909) 78 IV. CHARLES DARWIN AND THE UNIVERSITY OF CAMBRIDGE (Cambridge, June 23, 1909) 84 V. THE VALUE OF COLOUR IN THE STRUGGLE FOR LIFE 92 VI. MIMICRY IN THE BUTTERFLIES OF NORTH AMERICA (Baltimore, Dec. 31, 1908) 144 VII. LETTERS FROM CHARLES DARWIN TO ROLAND TRIMEN (1863-71) 213 APPENDIX A. CHARLES DARWIN AND THE HYPOTHESIS OF MULTIPLE ORIGINS 247 APPENDIX B. DARWIN AND EVOLUTION BY MUTATION. 254 APPENDIX C. FURTHER PROOF THAT SCIENTIFIC WORK WAS NECESSARY FOR DARWIN 256
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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.
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I FIFTY YEARS OF DARWINISM One of the centennial addresses in honour of Charles Darwin, read before the American Association for the Advancement of Science, Baltimore, Friday, January 1, 1909. Revised and extended. ON this historic occasion it is of special interest to reflect for a few moments on the part played by the New World in the origin and growth of the great intellectual force which dominates the past half-century. The central doctrine of evolution, quite apart from any explanation of
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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.
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Palaeontology, famed throughout the world, has exercised a profound influence on the growth and direction of evolutionary thought. The scale and perfection of its splendid fossil records have attracted the services of a large band of the most eminent and successful labourers, of whom I can only mention the leaders:—Leidy, Cope, Marsh, Osborn, and Scott, in the Verte [page] 3 AMERICA AND EVOLUTIO
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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.
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brata; Hall, Hyatt, and Walcott in the Invertebrata. The study of American Palaeontology was at first believed to support a Neo-Lamarckian view of evolution, but this, as well as the hypothesis of polyphyletic or multiple Origins (see Appendix A, p. 247), was undermined by the teachings of Weismann. Difficulties for which the Lamarckian theory had been invoked were met by the hypothesis of Organic Selection, suggested by Baldwin and Osborn, and in England by Lloyd Morgan. Weismann's contention
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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.
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question. THE INFLUENCE OF LYELL UPON CHARLES DARWIN The limits of space compel me to pass by the youth of Charles Darwin, with the influence of school, Edinburgh and Cambridge, including his intimacy with Henslow—a friendship leading to the voyage in the Beagle. We must also pass by his earliest convictions on evolution, the 'acquired' in the sense of 'acquired characters'; 'changement acquis' is the form employed many years later by Lamarck. 1 More Letters of Charles Darwin. Edited by Francis
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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.
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belief that the effect was even greater and more significant than has been supposed. Huxley has maintained with great force that the way was paved for Darwin by Lyell s Principles of Geology far more thoroughly than by any other work. '.. . consistent uniformitarianism postulates evolution as much in the organic as in the inorganic world. The origin of a new species by other than natural agencies would be a vastly greater catastrophe than any of those which Lyell successfully eliminated from sober
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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.
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'COMING EVENTS CAST THEIR SHADOWS BEFORE' The characteristic feature in which Natural Selection differs from every other attempt to solve the problem of evolution is the account taken of the struggle for existence, and the role assigned to it. Professor Osborn1 refers to the keen appreciation of this struggle in Tennyson's noble poem, In Memoriam, the dedication of which is dated 1849, ten years before the Origin. The poet is disquieted by:— 'Nature red in tooth and claw With ravine,…..' and
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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.
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Selection by so distinguished a botanist as Carl Nägeli turns out to be most unsatisfactory the moment it is examined. The idea of evolution under the compulsion of an internal force residing in the idioplasm is in essence but little removed from special creation. On the subject of Nägeli's criticisms Darwin wrote, Aug. 10, 1869, to Lord Farrer:— 'It is to me delightful to see what appears a mere morphological character found to be of use. It pleases me the more [page] 21 DARWIN'S DEBT TO HOOKE
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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.
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Darwin also sent1 Asa Gray's defence of the Origin to Sir Charles Lyell, whom he was extremely anxious to convince of the truth of evolution. Asa Gray's religious convictions prevented the full acceptance of Natural Selection. He was ever inclined to believe in the Providential guidance of the stream of variation. He also apparently differed from Darwin in the extent to which he was inclined to interpret instincts as inherited habits.2 The same close intimacy and mutual help begun in the
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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.
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), Weismann raised the question of the hereditary transmission of acquired characters, the very foundation of Lamarckian and Spencerian evolution. Darwin accepted this transmission, and it was in order to account for 'such facts as the inherited effects of use and disuse, c.,'1 that he thought out his marvellous hypothesis of 1 See the letter to Huxley, July 12 (1865?), in Life and Letters, iii. 44. [page] 34 FIFTY YEARS OF DARWINIS
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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.
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could not accept, the naturalist who dictated in the last year of his life the unalterable conviction that these teachings were false. I name no names, but I think of leaders of organic evolution in this Continent and in Europe, —sons of great men to whom the new thoughts brought deepest grief, men who struggled tenaciously and indomitably against them. And full many a household unknown to fame was the scene of the same poignant contrast, was torn by the same dramatic conflict. We have passed
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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.
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ago. Turning now to the ancient Universities as the lists where new ideas are compelled to undergo the trial of combat, we observe that the battle of evolution began with the dramatic encounter between Huxley and Wilberforce at the meeting of the British Association at Oxford, in 1860, and, according to Professor Alfred Newton, came to a close with the victory of the new teachings, only two years later, at the meeting of the same Association at Cambridge. Whatever happened in the great arena
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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.
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to them as those of a gall, or, indeed, as the colour of an amethyst or ruby is to these gems.'2 Incidental colours remain as available assets of the organism ready to be turned to account by Natural Selection. It is a probable speculation 1 Poulton, Essays on Evolution, Oxford, 1908, 293-382. 2 More Letters, i. 854, 855. See also the admirable account of incidental colours in Descent of Man (2nd edit., 1874), 261, 262. [page] 94 THE VALUE OF COLOU
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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.
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AND ADAPTATION In the department of Biology, which forms the subject of this essay, the adaptation of means to an end is probably more evident than in any other; and it is therefore of interest to compare, in a brief introductory section, the older with the newer teleological views. The distinctive feature of Natural Selection as contrasted with other attempts to explain the process of evolution is the part played by the struggle for existence. All naturalists in all ages must have known
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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.
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of the species native to its second home, the problem gains a special interest and fascination.1 We are chiefly dealing with the fleeting and changeable element of colour, and we expect to find and we do find evidence of a comparatively rapid evolution. The invasion of a fresh model is for certain species an unusually sudden change in the forces of the environment, and in some instances we have grounds for the belief that the mimetic response has not been long delayed. MIMICRY AND SEX Ever
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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.
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. Thus if the female appear in two different forms and the male in only one, it will be twice as probable that she will happen to possess a sufficient foundation for the evolution of Mimicry. (3) The appearance of melanic or partially melanic forms in the female has been of very great service, providing as it does a change of ground-colour. Thus the Mimicry of the black [page] 137 CONCLUSIONS ON MIMICRY AND SE
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