On the Making of Man

¹¹ Moreover we plant in the ground the kernels of fruits, and portions torn from roots, not deprived by death of the vital power which naturally resides in them, but preserving in themselves, hidden indeed, yet surely living, the property of their prototype; the earth that surrounds them does not implant such a power from without, infusing it from itself (for surely then even dead wood would proceed to growth), but it makes that manifest which resides in them, nourishing it by its own moisture, perfecting the plant into root, and bark, and pith, and shoots of branches, which could not happen were not a natural power implanted with it, which drawing to itself from its surroundings its kindred and proper nourishment, becomes a bush, or a tree, or an ear of grain, or some plant of the class of shrubs.