Page:Popular Science Monthly Volume 24.djvu/121

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tant than the similar efforts of all his contemporaries, even than the similar work of Geoffroy Saint-Hilaire, and styles it "the greatest production of the great literary epoch of the beginning of our century." According to this naturalist's review of Lamarck's system, it supposes that "all the forms of animals and plants which we distinguish as species have only a relatively temporary stability, and the varieties are incipient species. Therefore the form-group or type of the species is just as much an artificial product of our analyzing reason as are the genus, order, class, and other categories of the system. Changes in the conditions of life on one side, the use and non-use of the organs on the other side, constantly exert a formative influence on the organism; through adaptation they bring about a gradual metamorphosis of forms, the principal features of which are transmitted by inheritance from generation to generation. The whole system of animals and plants is thus peculiarly their genealogical tree, and reveals to us the relations of their natural blood-kinship. The course of development on the globe has therefore been continuous and unbroken, like that of the earth itself. . . . Lamarck regarded life as only a very complicated physical phenomenon; for all the phenomena of life depend on mechanical antecedents, which are themselves dependent on the adaptedness of the organic matter. Even the phenomena of the mental life are not different in this respect from the others. For the conceptions and acts of the mind depend upon motor-organs in the central nerve-system." He did not shrink from the solution of the difficult question of the origin of life on the globe, and assumed "that the common primitive forms of all organisms were absolutely simple beings which originated by spontaneous generation, under the combined operation of different physical causes, out of the inorganic matter in water." "Undoubtedly," adds Herr Haeckel, "the greatest defect in Lamarck's work was the insufficient number of observations and experiments which he adduced in proof of his far-reaching theories." A great part of Darwin's immense success was owing to the fact that he was backed by a host of clear and convincing observations and experiments, while "poor Lamarck, trusting too much to the logical acumen of the naturalist, in great part neglected them."