Professor Le Dantec leaves the subject where he took it up, with the origin of life and the life processes unaccounted for.  His work is a description, and not an explanation.  All our ideas about vitality, or an unknown factor in the organic world, he calls “mystic” and unscientific.  A sharp line of demarcation between living and non-living bodies is not permissible.  This, he says, is the anthropomorphic error which puts some mysterious quality or force in all bodies considered to be living.  To Le Dantec, the difference between the quick and the dead is of the same order as the difference which exists between two chemical compounds—­for example, as that which exists between alcohol and an aldehyde, a liquid that has two less atoms of hydrogen in its composition.  Modify your chemistry a little, add or subtract an atom or two, more or less, of this or that gas, and dead matter thrills into life, or living matter sinks to the inert.  In other words, life is the gift of chemistry, its particular essence is of the chemical order—­a bold inference from the fact that there is no life without chemical reactions, no life without oxidation.  Yet chemical reactions in the laboratory cannot produce life.  With Le Dantec, biology, like geology and astronomy, is only applied mechanics and chemistry.

III

Such is the result of the rigidly objective study of life—­the only method analytical science can pursue.  The conception of vitality as a factor in itself answers to nothing that the objective study of life can disclose; such a study reveals a closed circle of physical forces, chemical and mechanical, into which no immaterial force or principle can find entrance.  “The fact of being conscious,” Le Dantec says with emphasis, “does not intervene in the slightest degree in directing vital movements.”  But common sense and everyday observation tell us that states of consciousness do influence the bodily processes—­influence the circulation, the digestion, the secretions, the respiration.

An objective scientific study of a living body yields results not unlike those which we might get from an objective study of a book considered as something fabricated—­its materials, its construction, its typography, its binding, the number of its chapters and pages, and so on—­without giving any heed to the meaning of the book—­its ideas, the human soul and personality that it embodies, the occasion that gave rise to it, indeed all its subjective and immaterial aspects.  All these things, the whole significance of the volume, would elude scientific analysis.  It would seem to be a manufactured article, representing only so much mechanics and chemistry.  It is the same with the living body.  Unless we permit ourselves to go behind the mere facts, the mere mechanics and chemistry of life phenomena, and interpret them in the light of immaterial principles, in short, unless we apply some sort of philosophy to them, the