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was restored to merited honour by Darwin, but more especially by Haeckel, and quite recently in France by Ch. Martins. This is J. B. Lamarck, who first formulated the doctrine of Descent, and in 1804 actually propounded all the propositions which Darwin has constructed afresh and more completely. Lamarck proclaimed that it is merely our limited powers of comprehension that demand the erection of systems, whereas all systematic definitions and gradations are of artificial
We may be assured that nature has produced neither orders, families, genera, nor immutable species, but merely individuals which succeed one another, and resemble those from whom they descend. But these individuals belong to infinitely divergent races, which continue so long as they are unaffected by any cause producing alteration. Starting from species, like ourselves, he demonstrates their instability. From comparisons of the facts of hybridization and the formation of varieties, he inferred "that all organizations are true productions of Nature, gradually evolved in the course of a long succession of ages; that in her progress, Nature began, and even now always begins again, with the formation of the simplest organic bodies, and that she directly forms these only, namely, those lowest living beings which have been designated as spontaneous generations."
Variations and transformations supervene, according to Lamarck, through external influences; in the lapse of ages they become essential differences; so that, after many successive generations, individuals which originally belonged to another species ultimately find themselves converted into a new one. The limited period of our existence has accustomed us to a standard of time so
short as to give rise to the vulgar and false hypothesis of stability and immutability. The transformation is effected by the obligation of the individual to accommodate itself to the altered conditions of life. Fresh circumstances elicit fresh requirements and fresh activi
Great weight must be laid on the use or disuse
of organs. "In every animal still in the course of development, the more frequent and sustained use of an organ gradually fortifies, developes and enlarges it, and endows it with strength proportional to the duration of this use; while the persistent disuse of an organ imperceptibly weakens and deteriorates it, diminishes its efficiency in an increasing ratio, and ultimately destroys it." "And thus," he says, "nature exhibits living beings merely as individuals succeeding one another in generations; species have only a relative stability, and are only transiently immutable.”
Lamarck touches upon the struggle of each against all (I. 99, and elsewhere), but does not discover the term Natural Selection. He is fully conscious of the two factors, heredity and adaptation, but his theories and convictions lack the emphasis of detailed evidence. Yet his subtle apprehension of life may be evinced by his interpretation of instinct. According to him, all acts of instinct are effected by incitement, exercised upon the nervous system by acquired inclinations (penchans acquis); and these acts, not being the product of deliberation, choice, or judgment, certainly and unerringly satisfy the requirements experienced and the inclinations resulting from habit. But if these inclinations to maintain the habit and renew the actions related to them, are once acquired, they are henceforward
transmitted to the individuals by means of reproduction, which maintains the structure and the disposition of the parts in the condition attained, so that the same inclination pre-exists in the young individuals before they put it in practice. This explanation, as Darwin has shown, certainly does not suffice for all the facts of instinct, yet it stands far above the modern "Philosophy of the Unconscious" (Philosophie des Unbewussten), which places the organisms by which the instincts are effectuated, under the sway of an extraneous metaphysical Being who governs it in subservience to design."
Lyell and Modern Geology--Darwin's Theory of Selection-Beginning of Life.
EVER since mankind has consciously laboured in the field of intellect, pre-eminent men have existed, who, reasoning more rapidly than their contemporaries, have outstripped them in the apprehension of great truths and the recognition of important laws. But it is a great temptation to set too high a value on these anticipations; and in all cases in which these intellectual exploits are concerned, it will be discovered that, so to speak, they floated in the air, and that it was merely a keener scent and a so-called intuition resting on unconscious inferences, which exalted the privileged being above his less sharp-sighted neighbours.
Great scientific crises, revolutions in the domain of intellect, are prepared long beforehand; the watch-word rarely comes too early and is seldom pronounced in accents unintelligible to contemporaries; as a rule, if the change has not been altogether gradual and almost unperceived, but if on the contrary the veil has been suddenly drawn aside by one of these chosen spirits, scales fall, as it were, from the eyes of fellow-labourers and spectators, and the rapidity with which the new
theory makes its way affords the best evidence that it took shape and was proclaimed at the proper moment.
That the doctrine of Descent was likewise no utterly startling apparition, even though it leapt forth from the head of Darwin, its greatest representative, like an armed Minerva-of this we have cited at least a few of the many vouchers. That its time had come,-that it was indeed more than time, unless the science of the nature of life, and Biology in general, was to be unduly backward,— is shown by the development of Geology, which thirty years prior to Darwin, after many favourable forecasts, struck upon the right road to the knowledge of causes. The doctrine of the formation and evolution of the earth, especially in its earlier phases, during which Life, in the sense generally attached to the word, originated and became permanent on our Planet,-this science of Geology is intimately allied with our important theme. Modern Geology, especially as connected with the name of Charles Lyell, must sooner or later have necessitated an analogous treatment of vegetal and animal lore, and we can only wonder that the crisis was so long delayed. The exposition of the doctrine of Descent must, therefore, be introduced and initiated by a reference, however brief, to modern Geology.
The first edition of Lyell's "Principles of Geology appeared in 1830. The tenth, published in 1866, gave him an opportunity of professing his full adhesion to the Darwinian doctrines, to the development of which he had given so great an impulse. Since 1872, the eleventh edition of this masterpiece has been before the world. It treats of the investigation of the lasting effects of causes now in operation, as data from which inferences