Such as they are, they maintain a status incomparable with that of non-living things. Incomparable, for instance, as regards the water in which they float. The contrast is startling despite its familiarity. An amœba incarnates a purpose; it embodies a spark of personal existence, unconsciously swaying the forces of inorganic nature towards the ends of its own well-being. The subordination is most real, though profoundly mysterious. In the organic and the inorganic worlds the same laws hold good; the same ultimate atoms exert their preferences in each; in neither is an uncaused effect possible. A bullet can no more be fired from a gun that has no charge than a man can lift a finger without a corresponding outlay of food-products. Accordingly, while plants store and animals expend energy, plants and animals are equally incompetent for its origination. What they can do is to appropriate and specifically apply it; and herein resides the essence of life. 'It would seem,' Sir George Stokes wrote in 1893,[126] 'to be something of the nature of a directing power, not counteracting the action of the physical forces, but guiding them into a determined channel.' What the power is in itself it would be futile to seek to define. We are only sure of its being extra-physical. Matter cannot evolve a principle which disposes of it as its master. Evolution means only the unfolding into self-evidence of something already obscurely present. The 'latent process' (to use a Baconian term) of the hatching of an egg is typical and instructive. Yet it is not the less recondite for being daily conducted before our eyes. A concourse of suns, indeed, fails to impress us with the unutterable wonder of the 'flower in the crannied wall' apostrophized by the last great poet of the nineteenth century.