without intermission to expand and to contract; alternately to suffer decomposition and to accomplish its recomposition. A blank sameness, an almost thought-paralyzing monotony of life, is thus exhibited by many of these primitive beings. Only always expansion and contraction, by means of that same kind of reintegration and disintegration. Nothing more, apparently. It would almost seem as if the anti-evolutionists were right after all in their main view of life. It, indeed, resembles most strikingly a perpetual seesaw; the very same thing always over again—a mere organic toy, ingeniously contrived, so as to maintain itself intact, in spite of encroaching outside influences; the unmeaning disturbance of a most delicate equilibrium, and the following exact reëstablishment of that very same equilibrium. This, reduced to its most simple biological expression, is the foundation of the opinions which oppose evolutionism by maintaining the permanence of organic species, or their archetypal origin.
All turns upon the decision of the following point: Does there exist an absolute equivalence, a total identity between the compound separated from the protoplasm by the dynamical influences of the medium and the restitutive compound taken up from the medium by dint of the specific affinities inherent in the protoplasm? Does there normally exist a complete fixity in the observed play of equilibrated activities? Does this ever-reiterated exhibition of motility fulfill only its own motory object? Or, translated into the language of volition, Does the organism merely move to feed, and feed to move? This, in truth, is the pith of this momentous question.
The chemical affinities inwoven in the protoplasm are, like all chemical affinities, of a most definite kind. This chemical definiteness is even outwardly manifest in the strict preservation of all peculiarities in the different living substances which constitute the varieties of monera. Now, this functional restitution of protoplasm is effected entirely by means of these inherent chemical affinities. It is clear, therefore, that, if a deviation is ever to occur in the beats of this chemically so firmly established vital pendulum, it can be operated only in two ways: Either the dynamical influences succeed in splitting off from the expanding protoplasm a slightly-differing molecule, affecting thus the total chemical equilibrium in such a manner as to bring about a somewhat altered reintegration of the same, or the restitutive material possesses, by dint of its own peculiar molecular composition, the power of forcing the disintegrated substance to reintegrate itself with some slight deviation.
In other words, variations in the molecular constitution of the protoplasm can only be effected either by the dynamical influences of the medium, or by the restitutive material of the medium. Spontaneous variations, starting from within the already-established molecular equilibrium of the protoplasm itself, would be like all other spontaneous changes, an inadmissible supposition, an effect without a cause.