CHAPTER I.

RISE OF THE DARWINIAN THEORIES.

§ 1. Direct Predecessors.-Lamarck.

The first man who gave direct expression to the idea of a successive generation of the species through transmutation, and who attempted to follow it up in a scientific way, was the French naturalist and philosopher, Jean Lamarck, born 1744. In the year 1801, and subsequently, he published his views, first in smaller essays and afterward more in detail in his "Philosophie Zoologique," which appeared in 1809, and in the first volume of his "Histoire Naturelle des Animaux sans Vertèbres, published in 1815. In these works Lamarck upholds fully the descent and evolution theory, and maintains that the simplest organisms are generated through a generatio spontanea, which is still taking place; but that all the more developed organisms, including man, are descended through a gradual change from other species. With this theory, he put himself in direct and conscious opposition to the old doctrine of the immutability of species and their characteristics, which had been ably maintained by Linnæus, and also made some attempts at explanation which approach very nearly the selection theory. A change in the physical conditions of life, especially the force of habit in the use or disuse of the organs, the inheritance of physical and psychical

me as

of comfective

qualities thus attained, and the extension of the process of transmutation into extraordinarily long periods of time with very slight changes, are also, in his view, the probable causes of the variation and development of the species. He only lacks the idea of a natural selection in the struggle for existence, and the comparison of the processes in nature with the methodical selection of man in the breeding of domestic animals and plants, to identify his views with those of Darwin.

At first, Lamarck met only with violent opposition; but after a little while his views ceased to attract attention. The time had not yet come to make such an attempt at observing nature from the standpoint of evolution. The sciences which favor such a mode of observation, and even demand it-such as comparative anatomy and physiology and the history of the development of the different plants and animals-were only in their infancy, or were-like palæontology and the comparative geography of plants and animals-not yet in existence. The influence of Linnæus, whose views diametrically opposed those of Lamarck, predominated over all the investigations of natural science; Buffon, who favored the ideas of Lamarck, and loved to trace a unity in natural phenomena, was too instable in his investigations and views to arrive at a comprehensive principle; and even the eminent naturalist, Cuvier, of Montpellier, showed in his observation of nature a predilection for analysis rather than synthesis, and although his comprehensive mind inclined to generalize and explain, he placed himself in decided opposition to a theory which was founded only on a few decisive facts.

This last mentioned deficiency seems to have been

the main cause of Lamarck's views soon being lost sight of. They nowhere found a support in facts; the force of habit played in them an exaggerated and unnatural rôle; the different illustrations of them-such as the long neck of the giraffe explained by the permanent and inherited habit of browsing on the branches of high trees, or the web on the toes of frogs, swimming-birds, etc., explained by the habit of swimming-were talked about and laughed at more as curiosities than as worthy of serious consideration.

Only twice after this did the question put by Lamarck attract wider attention from the learned world. The first time was when, in 1830, the bitter contest arose at the Academy of Paris, between Cuvier and Etienne Geoffroy St. Hilaire, the father of Isidor G. St. Hilaire. Geoffroy St. Hilaire had views similar to Lamarck's, but reached them from quite a different standpoint-from the observation of the analogy and homology of the organs; and accounted for the variation of species, not by the use or disuse of the organs, but on the one hand by the common original type of the organs, and on the other by the varied influence of the surroundings-the monde ambiant. Lamarck himself seems not to have been mentioned in this contest. The controversy turned much more on the question whether in observing nature we can proceed by synthesis and find in the analogies of the organisms the principles for explaining the real connection between the different organic forms, or whether the analytical process is the only correct one, and the synthetical should be discarded. The solution of it will probably be, that the one process must be supplemented by the

other, as Goethe has already shown in his account of this controversy; but at that time it was decided in favor of the analytical principle, and the question was for the time dropped. It came up for a second time, but created little excitement, in 1844, when an anonymous. work, "Vestiges of the Natural History of Creation,” directed the attention and the interest of scientists again to Lamarck and his doctrine. But this interest also soon came to an end, until through Darwin's first publication the half-forgotten man again suddenly attained great honor.

Those who wish to form a closer acquaintance with the different advocates of the evolution theory before Darwin's appearance, will find them carefully arranged in the historical sketch which Darwin gives in the introduction to his work on "The Origin of Species "; and the most important extracts of Lamarck's "Philosophie Zoologique" are to be found in Oscar Schmidt's "Descent and Darwinism."*

§ 2. Indirect Preparations.

While thus the ideas of Lamarck gradually fell into partial oblivion, yet contemporaneous with and following them arose several other series of thoughts, views, and investigations, which, although they only indirectly prepared for the revival of the evolution theory, yet exercised a deeper and more lasting influence on the minds of scientists. We refer to the ideas in regard to natural phenomena held during the first decades of our century; further, to the principles of comparative anatomy which, up to the present time, partly dependent

*The International Scientific Series." No. XIII.

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and partly independent of natural philosophy, have been expressed, valued, and admired as leading thoughts; and, lastly, to the empiric results of comparative anatomical and biological investigations in palæontology and geology, as attained by the help of those very principles. And even physics and astronomy had to coöperate in preparing the way for the idea of evolution.

The philosophical ideas referred to, together with the points of view and results of comparative anatomy, led more and more decisively to the idea of an original form, or type, which retains its identity in all the modifications of form in plants and animals; and of a groundplan, which is realized in the systems of the plant and animal world in higher and higher differentiations and in more and more developed modifications, diverging farther and farther from the prototype until it reaches its highest form, still reducible to the prototypes, in the most highly organized dicotyledons in plants, and in the animal world in the mammalia, and lastly in man.

Men like Cuvier and Geoffroy St. Hilaire, who otherwise stand diametrically opposed to each other, unite in these and kindred ideas. The naturalist Oken attains the same result, tinged with the views of Schelling; the poet Goethe, from an intuitive knowledge of nature, arrived at the same conclusion. The former, during a journey in the Hartz Mountains, at the sight of a bleached deer's skull, and the latter, upon picking up a sheep's skull in the Jewish cemetery at Venice, were struck by the same thought: the skull is only a modified vertebra. Oken founded upon this idea and kindred analogies his profound philosophy of the system of animals and plants which comes very near to the evolution the