and offers no resistance; it is subject to no mechanical laws, and no instrument or experiment that science has yet devised can detect its presence; it has neither centre nor circumference, neither extension nor boundary.  And yet science is as convinced of its existence as of the solid ground beneath our feet.  It is the one final reality in the universe, if we may not say that it is the universe.  Tremors or vibrations in it reach the eye and make an impression that we call light; electrical oscillations in it are the source of other phenomena.  It is the fountain-head of all potential energy.  The ether is an invention of the scientific imagination.  We had to have it to account for light, gravity, and the action of one body upon another at a distance, as well as to account for other phenomena.  The ether is not a body, it is a medium.  All bodies are in motion; matter moves; the ether is in a state of absolute rest.  Says Sir Oliver Lodge, “The ether is strained, and has the property of exerting strain and recoil.”  An electron is like a knot in the ether.  The ether is the fluid of fluids, yet its tension or strain is so great that it is immeasurably more dense than anything else—­a phenomenon that may be paralleled by a jet of water at such speed that it cannot be cut with a sword or severed by a hammer.  It is so subtle or imponderable that solid bodies are as vacuums to it, and so pervasive that all conceivable space is filled with it; “so full,” says Clerk Maxwell, “that no human power can remove it from the smallest portion of space, or produce the slightest flaw in its infinite continuity.”

The scientific imagination, in its attempts to master the workings of the material universe, has thus given us a creation which in many of its attributes rivals Omnipotence.  It is the sum of all contradictions, and the source of all reality.  The gross matter which we see and feel is one state of it; electricity, which is without form and void, is another state of it; and our minds and souls, Sir Oliver Lodge intimates, may be still another state of it.  But all these theories of physical science are justified by their fruits.  The atomic theory of matter, and the kinetic theory of gases, are mathematically demonstrated.  However unreal and fantastic they may appear to our practical faculties, conversant only with ponderable bodies, they bear the test of the most rigid and exact experimentation.

V

After we have marveled over all these hidden things, and been impressed by the world within world of the material universe, do we get any nearer to the mystery of life?  Can we see where the tremendous change from the non-living to the living takes place?  Can we evoke life from the omnipotent ether, or see it arise in the whirling stream of atoms and electrons?  Molecular science opens up to us a world where the infinitely little matches the infinitely great, where matter is dematerialized and answers to many of the