These natural formations, tending to generate and realise each its ideal, are, as it were, eddies in the universal flux, produced no less mechanically, doubtless, than the onward current, yet seeming to arrest or to reverse it. Inheritance arrests the flux by repeating a series of phases with a recognisable rhythm; memory reverses it by modifying this rhythm itself by the integration of earlier phases into those that supervene. Inheritance and memory make human stability. This stability is relative, being still a mode of flux, and consists fundamentally in repetition. Repetition marks some progress on mere continuity, since it preserves form and disregards time and matter. Inheritance is repetition on a larger scale, not excluding spontaneous variations; while habit and memory are a sort of heredity within the individual, since here an old perception reappears, by way of atavism, in the midst of a forward march. Life is thus enriched and reaction adapted to a wider field; much as a note is enriched by its overtones, and by the tensions, inherited from the preceding notes, which give it a new setting. [Sidenote: Continuity necessary to progress.] Progress, far from consisting in change, depends on retentiveness. When change is absolute there remains no being to improve and no direction is set for possible improvement: and when experience is not retained, as among savages, infancy is perpetual. Those who cannot remember the past are condemned to repeat it. In the first stage of life the mind is frivolous and easily distracted; it misses progress by failing in consecutiveness and persistence. This is the condition of children and barbarians, in whom instinct has learned nothing from experience. In a second stage men are docile to events, plastic to new habits and suggestions, yet able to graft them on original instincts, which they thus bring to fuller satisfaction. This is the plane of manhood and true progress. Last comes a stage when retentiveness is exhausted and all that happens is at once forgotten; a vain, because unpractical, repetition of the past takes the place of plasticity and fertile readaptation. In a moving world readaptation is the price of longevity. The hard shell, far from protecting the vital principle, condemns it to die down slowly and be gradually chilled; immortality in such a case must have been secured earlier, by giving birth to a generation plastic to the contemporary world and able to retain its lessons. Thus old age is as forgetful as youth, and more incorrigible; it displays the same inattentiveness to conditions; its memory becomes self-repeating and degenerates into an instinctive reaction, like a bird’s chirp. [Sidenote: Limits of variation. Spirit a heritage.]