Outlines of the Earths History | Page 8

that at each stage in the history of the earth another assemblage of species peopled the waters and the lands.
At first naturalists concerned themselves only with the external forms of living creatures; but they soon came to perceive that the way in which these organisms worked, their physiology, in a word, afforded matters for extended inquiry. These researches have developed the science of physiology, or the laws of bodily action, on many accounts the most modern and extensive of our new acquisitions of natural learning. Through these studies we have come to know something of the laws or principles by which life is handed on from generation to generation, and by which the gradations of structure have been advanced from the simple creatures which appear like bits of animated jelly to the body and mind of man.
The greatest contribution which modern naturalists have made to knowledge concerns the origin of organic species. The students of a century ago believed that all these different kinds had been suddenly created either through natural law or by the immediate will of God. We now know that from the beginning of organic life in the remote past to the present day one kind of animal or plant has been in a natural and essentially gradual way converted into the species which was to be its successor, so that all the vast and complicated assemblage of kinds which now exists has been derived by a process of change from the forms which in earlier ages dwelt upon this planet. The exact manner in which these alterations were produced is not yet determined, but in large part it has evidently been brought about by the method indicated by Mr. Darwin, through the survival of the fittest individuals in the struggle for existence.
Until men came to have a clear conception as to the spherical form of the earth, it was impossible for them to begin any intelligent inquiries concerning its structure or history. The Greeks knew the earth to be a sphere, but this knowledge was lost among the early Christian people, and it was not until about four hundred years ago that men again came to see that they dwelt upon a globe. On the basis of this understanding the science of geology, which had in a way been founded by the Greeks, was revived. As this science depends upon the knowledge which we have gained of astronomy, physics, chemistry, and biology, all of which branches of learning have to be used in explaining the history of the earth, the advance which has been made has been relatively slow. Geology as a whole is the least perfectly organized of all the divisions of learning. A special difficulty peculiar to this science has also served to hinder its development. All the other branches of learning deal mainly, if not altogether, with the conditions of Nature as they now exist. In this alone is it necessary at every step to take account of actions which have been performed in the remote past.
It is an easy matter for the students of to-day to imagine that the earth has long endured; but to our forefathers, who were educated in the view that it had been brought from nothingness into existence about seven thousand years ago, it was most difficult and for a time impossible to believe in its real antiquity. Endeavouring, as they naturally did, to account for all the wonderful revolutions, the history of which is written in the pages of the great stone book, the early geologists supposed this planet to have been the seat of frequent and violent changes, each of which revolutionized its shape and destroyed its living tenants. It was only very gradually that they became convinced that a hundred million years or more have elapsed since the dawn of life on the earth, and that in this vast period the march of events has been steadfast, the changes taking place at about the same rate in which they are now going on. As yet this conception as to the history of our sphere has not become the general property of the people, but the fact of it is recognised by all those who have attentively studied the matter. It is now as well ascertained as any of the other truths which science has disclosed to us.
It is instructive to note the historic outlines of scientific development. The most conspicuous truth which this history discloses is that all science has had its origin and almost all its development among the peoples belonging to the Aryan race. This body of folk appears to have taken on its race characteristics, acquired its original language, its modes of action, and the foundations of its religion in that part of northern Europe which is about the Baltic Sea. Thence