The disharmonies in Nature in both the living and the non-living worlds tend to correct themselves. When Nature cannot make both ends meet, she diminishes her girth. If there is not food enough for her creatures, she lessens the number of mouths to be fed. A surplus of food, on the other hand, tends to multiply the mouths.
Man often introduces an element of disorder into Nature. His work in deforesting the land brings on floods and the opposite conditions of drought. He destroys the natural checks and compensations.
The swells that beat upon the shores of the ocean are not merely the result of a local agitation of the waters. The pulse of the earth is in them. The pulse of the sun and the moon is in them. They are more cosmic than terrestrial. The earth wears her seas like a loose garment which the sun and moon constantly pluck at and shift from side to side. Only the ocean feels the tidal impulse, the heavenly influences. The great inland bodies of water are unresponsive to them--they are too small for the meshes of the solar and lunar net. Is it not equally true that only great souls are moved by the great fundamental questions of life? What a puzzle the tides must have been to early man! What proof they afford of the cosmic forces that play upon us at all times and hold us in their net! Without the proof they afford, we should not know how we are tied to the solar system. The lazy, reluctant waters--how they follow the sun and moon, "with fluid step," as Whitman says, "round the world"! The land feels the pull also and would follow if it could. But the mobile clouds go their way, and the aerial ocean makes no sign. The pull of the sun and the moon is upon you and me also, but we are all unconscious of it. We are bodies too slight to affect the beam of the huge scale.
It is remarkable, I think, that Professor Osborn, in his "Origin and Evolution of Life," makes no account of the micro-organisms or unicellular lives that are older than the continents, older than the Cambrian rocks, and that have survived unchanged even to our times. I saw in the Grand Cañon of the Colorado where they were laid down horizontally on the old Azoic or original rocks, as if by the hand of a mason building the foundation of a superstructure. All the vast series of limestone rocks are made up from the skeletons of minute living bodies. Other strata of rocks are made up of the skeletons of diatoms. Some of our polishing powders are made from these rocks. Formed of pure silex, these rocks are made up of the skeletons of organisms of many exquisite forms, _Foraminiferæ_. The Pyramids are said to be built of rocks formed by these organisms. "No single group of the animal kingdom," says Mr. W. B. Carpenter, "has contributed, or is at present contributing, so largely as has the _Foraminiferæ_ to the formation of the earth's crust." In the face of these facts, how unsatisfactory seem Professor Osborn's statements that life probably originated on the continents, either in the moist crevices of rocks or soils, in the fresh waters of continental pools, or in the slightly saline waters of the "bordering primordial seas." This last suggestion comes nearer the mark. There is no variation during geologic time of these primordial living organisms. All conceivable changes of environment have passed over them, but they change not. Bacteria struggle together, one form devouring another form. Unicellular life long precedes multicellular. Biologists usually begin with the latter; the former are fixed; with the latter begins development or evolution, and the peopling of the world with myriads of animal forms.