CHARLES DARWIN.

AMONG the men who have endeavoured to

establish a new or neglected theory, few have been rewarded by more rapid or more complete success than Charles Darwin in his efforts to obtain recognition for his views of the Origin of Species by means of Natural Selection. Few teachers have been regarded with such admiration by their disciples, or treated with so much respect by their opponents. No innovator has had less reason to complain of the indifference of his contemporaries. Round the 'Origin of Species," was waged for years the keenest phase of the contest between the followers of science and the adherents of tradition. More than one generation of naturalists have drawn the inspiration of their best work from their enthusiasm for Darwinism. From Darwin's books evolutionary ideas have permeated into all streams of thought, until natural selection, and the struggle for existence are discerned in operation in all the manifestations of life. The theory of the evolution of living beings by gradual modification was not new. Buffon had suggested it as the necessary conclusion to be drawn from a review of the phenomena of the organic world. Dr. Erasmus Darwin had proclaimed it with a power and eloquence due too much to vividness of imagination, and too little to profundity of research.

Lamarck devoted the latter half of his life to advocating the truth of evolution, and of his views. as to the causes of the process. In Britain, immediately before the publication of Darwin's arguments, Herbert Spencer had cogently urged the superiority of the hypothesis of evolution over that of special creation. Wells and Matthews had even reached the conception of natural selection. Yet the great majority of biologists were completely indifferent to these attempts to introduce a new leaven into the prevailing system of ideas concerning living beings. In spite of Buffon and Lamarck, Erasmus Darwin and Herbert Spencer, the greater number of naturalists still pursued their studies with the belief in the immutability of species as the background of their thoughts, and few conceived the possibility of treating as a scientific problem the question whether species were constant or plastic. One or two only, like Wallace, had reached conclusions similar to those of Darwin, and were prepared to support his arguments as soon as he produced them. But in a very short time after the appearance of the "Origin of Species," almost every naturalist of eminence had expressed his conviction of the truth of the conclusions expressed in that book. To Darwin clearly belongs the honour of having finally overthrown the dogma of the immutability of species, and so opened a broad path to the triumphant progress of biological researches. And it is also clear that the most successful weapon which Darwin wielded was the theory of natural selection. Although in many departments of biology it matters less what may be the cause of evolution than that the truth of descent with modification be apprehended, yet. it is evident that the arguments of Herbert Spencer

would have had little effect on naturalists, and on men of average intelligence, who were nevertheless completely convinced by Darwin's theory of natural

selection. So great and steadfast has been the allegiance of biologists in general to Darwin, that little attempt to criticise or develop his views was for a long time made by those who accepted the truth of organic evolution. Those who denied the modification of species altogether opposed Darwin energetically enough, but they fought against immensely superior forces. Some who were convinced of the truth

of organic evolution, and were not personally familiar with biological studies, questioned the allsufficiency of Darwin's explanation, but were usually met with the reply that only naturalists were competent to examine the question, and that naturalists were satisfied with the efficacy of natural selection. Only recently, now that the controversy between evolutionists and anti-evolutionists has subsided, has an impartial criticism of Darwin's position become possible, and the progressive development of the doctrine of organic evolution is now rapidly proceeding.

The mind's capacity for thinking about a phenomenon depends greatly on the ideas already acquired from those who have thought on it before. The possibility of the continuous modification of organisms had been suggested in a vague way before the time of Buffon; but it is obvious that Buffon received less assistance from predecessors than any of his successors received from him. The facts which most powerfully suggested to the great French naturalist the truth of organic evolution, were those of morphological relationship, of cultivation or domestication, and of

geographical distribution. The chief causes of modification, according to Buffon, are temperature and climate, the quality of food and the ills of slavery, by which last he means the conditions to which domesticated organisms are subjected by man. Buffon also drew attention to the selection exerted by man on domesticated animals as a means of perpetuating variations. But although he mentions the great tendency of organisms to increase in numbers, he draws no conclusion concerning natural selection by the struggle for existence. Erasmus Darwin was a disciple of Buffon. His arguments are based on the morphological relations of organisms, and the changes due to domestication; his idea of the cause of modification includes, besides the action of the environment, the effect of function, or, as Charles Darwin called it, use and disuse. Lamarck also was brought to his views by the morphological relations of organisms and the phenomena of domestication. Lamarck's idea of the cause of modification is as follows: the environment affects the habits of the animal, and the habits or functions affect the organs, and thus in the course of generations modifications of any extent are produced. Charles Darwin was early acquainted with the works of Buffon, Dr. Darwin and Lamarck, and thus his mind was ready as soon as his interest in living beings was excited, to consider their relation to the doctrine of evolution. At the same time it is evident that Darwin had more respect for the traditional and semi-religious belief in the immutability of species than he had for the earlier evolutionists.

In the 'Journal' he makes mention of Lamarck in discussing the blindness of the Brazilian Tucutuco. Considering the strictly subterranean habits of the