Lamarck, JEAN BAPTISTE PIERRE ANTOINE DE MONNET, CHEVALIER DE, evolutionist, born at Bazentin in Picardy, 1st August 1744, was educated for the church at the Jesuit College of Amiens, which he left at the age of seventeen to join the French army then warring in Germany. Having gained rapid promotion to officer's rank, he was sent in 1763 to the garrisons at Toulon and Monaco, where he became impressed with the Mediterranean flora. Accidental injuries led him to resign his position, and brought him to Paris, where he was forced to work in a banker's office, while his spare energies were devoted to the study of plants. In 1773, thanks in part to Buffon, he published a Flore Française, in which he applied a new analytical method of classification. As tutor to Buffon's son, he had the opportunity of visiting Holland, Germany, and Hungary. In 1774 he became a member of the French Academy and Garde de l'Herbier du Jardin du Roi—the nucleus of the famous post-revolutionary Jardin des Plantes. In one of the twelve chairs associated with this 'Jardin' Lamarck remained for twenty-five years as professor of what we would now call Invertebrate
Zoology. In 1801 or earlier he had begun to think actively about the relations and origin of species, expressing his conclusions in 1809 in his famous Philosophie Zoologique. Of his other great work, Histoire des Animaux sans Vertèbres, he published seven volumes between 1815 and 1822. Hard work and illness enfeebled his sight and left him for the last ten years of his life not only blind but poor. To one of his two daughters he dictated the last volume of his Invertebrate Zoology, while to keep himself alive he was forced to part with some of his treasured collections. Greater than his contemporaries and immediate successors dreamed, Lamarck died in comparative obscurity, 18th December 1829, aged eighty-five.
Apart from his contributions to classification and descriptive zoology, Lamarck had a twofold importance, as an expositor of the now accepted theory of descent, and as an inquirer into the still debated factors in evolution. It is easy to find in his Philosophie Zoologique passages which foreshadow many modern suggestions in regard to evolution, including the theory of natural selection; but the gist of his thinking is fairly expressed in the following propositions: (1) Every considerable and sustained change in the conditions of life produces a real change in the needs of the animals involved; (2) change of needs involves new habits; (3) altered function evokes change of structure, for parts formerly less used become with increased exercise more highly developed, other organs in default of use deteriorate and finally disappear, while new parts gradually arise in the organism by its own efforts from within (efforts de son sentiment intérieur); (4) gains or losses due to use or disuse are transmitted from parents to offspring.
There can be no doubt that Lamarck, though beyond doubt an independent thinker, was influenced by Buffon, and also perhaps by Erasmus Darwin, whose Loves of the Plants had been translated into French in 1799. On his contemporaries he exercised little influence—in fact it was not till the Darwinian revival of ætiology that the worth of Lamarck began to be justly appreciated. To those who deny the transmissibility of all characters individually acquired in direct response to changed functions and surroundings, the theory of evolution according to Lamarck seems to be based on an undemonstrated if not erroneous hypothesis; to those, on the other hand, who believe that individually acquired characters are transmissible from parents to offspring, Lamarck's theory is part of the solution of the evolutionist's puzzle. Thus, while the majority of naturalists in Britain and Germany side with Darwin and Weismann against Lamarck, there is in France a distinctly Lamarckian school, and a Réunion of his admirers has been instituted; while in America what are called 'Neo-Lamarckian' views are vigorously upheld by many naturalists of eminence, such as Cope, Hyatt, and Packard, who seek to explain evolution according to fundamental 'laws of growth,' plus the inherited effects of use and disuse and of environmental influence.
See BUFFON, DARWIN, DARWINIAN THEORY, EVOLUTION, HEREDITY, &c. S. Butler, Evolution, Old and New (Lond. 1879); J. V. Carus, Geschichte der Zoologie (1872); C. Claus, Lamarck als Begründer der Deseendenztheorie (1888); E. D. Cope, The Origin of the Fittest (Lond. and New York, 1887); Cuvier, 'Éloge de M. de Lamarck,' Acad. des Sciences (1832); M. Duval, 'Le Transformiste François Lamarck,' an admirable sketch of his life and work, Bull. Soc. Anthropol. tome xii. (Paris, 1889); E. Haeckel, Die Naturanschauung von Darwin, Goethe, und Lamarck (1882), and translation of his Natürliche Schöpfungsgeschichte; Lamarck, Histoire des Animaux sans Vertèbres (1815-22), re-edition by Deshayes and Milne-Edwards (1835-45); Philosophie Zoologique (1809), re-edition with valuable biographical introduction by Ch. Martins (1873); Lamarck, par un Groupe de Transformistes, ses Disciples (1887); A. S. Packard, Introduction to Standard Natural History (1885); and E. Perrier, La Philosophie Zoologique avant Darwin (1884).