or silicates.  When his seeds are sown in these solutions, we see inert matter germinating, “putting forth bud and stem and root and branch and leaf and fruit,” precisely as in the living vegetable kingdom.  It is not a growth by accretion, as in crystallization, but by intussusception, as in life.  These ghostly things exhibit the phenomena of circulation and respiration and nutrition, and a crude sort of reproduction by budding; they repair their injuries, and are able to perform periodic movements, just as does an animal or a plant; they have a period of vigorous youthful growth, of old age, of decay, and of death.  In form, in color, in texture, and in cell structure, they imitate so closely the cell structures of organic growth as to suggest something uncanny or diabolical.  And yet the author of them does not claim that they are alive.  They are not edible, they contain no protoplasm—­no starch or sugar or peptone or fats or carbohydrates.  These chemical creations by Dr. Leduc are still dead matter—­dead colloids—­only one remove from crystallization; on the road to life, fore-runners of life, but not life.  If he could set up the chlorophyllian process in his chemical reactions among inorganic compounds, the secret of life would be in his hands.  But only the green leaf can produce chlorophyll; and yet, which was first, the leaf or the chlorophyll?

Professor Czapek is convinced that “some substances must exist in protoplasm which are directly responsible for the life processes,” and yet the chemists cannot isolate and identify those substances.

How utterly unmechanical a living body is, at least how far it transcends mere mechanics is shown by what the chemists call “autolysis.”  Pulverize your watch, and you have completely destroyed everything that made it a watch except the dead matter; but pulverize or reduce to a pulp a living plant, and though you have destroyed all cell structure, you have not yet destroyed the living substance; you have annihilated the mechanism, but you have not killed the something that keeps up the life process.  Protoplasm takes time to die, but your machine stops instantly, and its elements are no more potent in a new machine than they were at first.  “In the pulp prepared by grinding down living organisms in a mortar, some vital phenomena continue for a long time.”  The life processes cease, and the substances or elements of the dead body remain as before.  Their chemical reactions are the same.  There is no new chemistry, no new mechanics, no new substance in a live body, but there is a new tendency or force or impulse acting in matter, inspiring it, so to speak, to new ends.  It is here that idealism parts company with exact science.  It is here that the philosophers go one way, and the rigid scientists the other.  It is from this point of view that the philosophy of Henri Bergson, based so largely as it is upon scientific material, has been so bitterly assailed from the scientific camp.