There is not a principle of roundness, though “nature centres into balls,” nor of squareness, though crystallization is in right lines, nor of aquosity, though two thirds of the surface of the earth is covered with water.  Can we on any better philosophical grounds say that there is a principle of vitality, though the earth swarms with living beings?  Yet the word vitality stands for a reality, it stands for a peculiar activity in matter—­for certain movements and characteristics for which we have no other term.  I fail to see any analogy between aquosity and that condition of matter we call vital or living.  Aquosity is not an activity, it is a property, the property of wetness; viscosity is a term to describe other conditions of matter; solidity, to describe still another condition; and opacity and transparency, to describe still others—­as they affect another of our senses.  But the vital activity in matter is a concrete reality.  With it there goes the organizing tendency or impulse, and upon it hinges the whole evolutionary movement of the biological history of the globe.  We can do all sorts of things with water and still keep its aquosity.  If we resolve it into its constituent gases we destroy its aquosity, but by uniting these gases chemically we have the wetness back again.  But if a body loses its vitality, its life, can we by the power of chemistry, or any other power within our reach, bring the vitality back to it?  Can we make the dead live?  You may bray your living body in a mortar, destroy every one of its myriad cells, and yet you may not extinguish the last spark of life; the protoplasm is still living.  But boil it or bake it and the vitality is gone, and all the art and science of mankind cannot bring it back again.  The physical and chemical activities remain after the vital activities have ceased.  Do we not then have to supply a non-chemical, a non-physical force or factor to account for the living body?  Is there no difference between the growth of a plant or an animal, and the increase in size of a sand-bank or a snow-bank, or a river delta? or between the wear and repair of a working-man’s body and the wear and repair of the machine he drives?  Excretion and secretion are not in the same categories.  The living and the non-living mark off the two grand divisions of matter in the world in which we live, as no two terms merely descriptive of chemical and physical phenomena ever can.  Life is a motion in matter, but of another order from that of the physico-chemical, though inseparable from it.  We may forego the convenient term “vital force.”  Modern science shies at the term “force.”  We must have force or energy or pressure of some kind to lift dead matter up into the myriad forms of life, though in the last analysis of it it may all date from the sun.  When it builds a living body, we call it a vital force; when it builds a gravel-bank, or moves a glacier, we call it a mechanical force; when it writes a poem or composes a symphony, we call it