takes place in the case of animals under domestication, and brought within the sweep of the law of natural selection the whole terrestrial world of sentient being, as Newton grasped in the law of gravitation all the suns and systems that people infinite space.

Complete acceptance as a vera causa has been sooner attained by natural selection than it was reached by gravitation, although the hypothesis of Newton was devised for the explanation of phenomena so simple in their character that they are as amenable to mathematical treatment as our notion of space. Scientific authorities in France hesitated to accept Newton's law until all doubt was dispelled by Clairaut, when in 1759 he calculated the retardation of Halley's comet, just ninety-four years after the great conception had first taken definite shape in Newton's mind. The intellectual joy with which the world learned that seeming irregularities in the movements of the planets were no violations of Newton's law, but were due to the mutual attraction of the planets, and therefore were confirmatory instances of the law; the exultation over the simultaneous discovery by Leverrier and Adams of the existence of Neptune from observation of the motions of Uranus, were evi

dence either of a faith needing to be strengthened into conviction, or of the perennial satisfaction from the gratification of a scientific instinct. But within some twenty years after the announcement of the Darwinian law, Professor Marsh's achievement of the genealogical tree of the horse, in which he traced its descent in unbroken series through some forty-five species from a five-toed mammal, has placed natural selection on the rock of complete demonstration. The very opposition which Darwin met with from scientific men affords ground of hope for the world. It shows at what an infantile stage science was when so many years of argumentation and research were needed to bring over the Lyells and Hookers, and Huxleys even, to Darwin's view. A preliminary dose of Hegelian thought, such as Dr Hutchison Stirling and others have administered with good effect, might have better smoothed the way for the acceptance of Darwin's theory than the one-sided principle of Sir Charles Lyell. The attitude even of Darwin's scientific contemporaries was like the fond clinging of men to the illusion of the sun revolving round the earth. Said Luther, of Copernicus, in his Table-Talk, "The fool wishes to upset the whole art of astronomy." We are only at the commencement of the Copernican era

of the science of organic being. A long lease of progress awaits the world before the period of Professor Huxley's dread. Thus says the happy Darwin:-"What a science natural history will be when we are in our graves, when all the laws of change are thought one of the most important facts of natural history" (Life and Letters, vol. ii. p. 81).

The general term "Struggle for Existence" is used by Darwin in a wide and metaphorical sense, with reference more to success in leaving progeny than to the life of the individual. A plant on a desert's edge struggles against the drought. A plant producing annually a thousand seeds, of which one only usually reaches maturity, struggles with the same and other kinds of plants already in possession of the ground. Several seedling mistletoes in close contiguity on the same branch struggle with each other and compete with other fruit-bearing plants for the patronage of birds to devour and disseminate their seeds. Not a little of the odium attaching to the Darwinian theory is due to the use of this term. It is inevitable that people should carry into Darwin's new conception of nature the evil associations of the word. By an unconscious personification they regard Nature as

waging an internecine war, with the bitterness that enters into the contests of human beings with each other; whereas Darwin had mainly in view, and certainly attached chief importance to the result of a natural process. In the great majority of his uses of the term it is a mere metaphorical expression. Mr Herbert Spencer's phrase "Survival of the Fittest," Darwin thought expressed his ideas more accurately. Of course, there is no struggle in the literal sense between several mistletoes that grow together on the same branch. But for the strong insistance of Darwin on the universality of Nature's effort to make progress, the prosperity of one mistletoe and the decline of its neighbour would never have occurred to us to be the result of a

struggle between them. In the offensive sense which the popular imagination attaches to the term, even the preying of animals upon each other for the sake of food is largely a metaphorical expression. The lion probably cherishes no enmity at heart towards the deer upon which he springs, but sets about the thing as a matter of course, much in the way a civilised man devours his beef-steak, to the disgust of a vegetarian. Of two youths of different capacities who start life side by side, one of whom succeeds and the other fails, we never dream of say

ing that they have struggled against each other in their life career. If we do say so, it is in a quite metaphorical sense. But we can hardly use the expression without importing into the matter a disagreeable element which belongs less to the facts than to our manner of viewing them. Of two brothers, one of whom is strong, and leaves a sturdy offspring, while the other is weakly, and leaves a puny offspring or none at all, it would be absurd to say that it was a struggle between the brothers which resulted in the strong sons and daughters of the one, and the puny children or the childlessness of the other. Yet this is a typical instance of what Darwin meant by the struggle for existence. It is mainly in consequence of this unfortunate association that people have taken up the idea of the opposition of Darwinism to all charitable treatment of the weak, as in sick hospitals, orphan homes, &c. Darwinism rightly interpreted no more frowns upon such institutions than it enjoins upon the strong brother to give needless aid to nature by deliberately strangling the weak brother or his puny offspring. Of course, a Darwinian would say the strong brother would be going against nature if he encouraged the weakling to propagate his kind; but in this all sensible and kind-hearted people would