to be modified again as it emerges from the opposite earth crust, but not annihilated. For my vision, however, this central light is not a necessity; my physical and mental development is such that the energy of darkness is communicable; I can respond to its touches on my nerves, and hence I can guide you in this dark cavern. I am all eye." "Ah!" I exclaimed, "that reminds me of a remark made by my former guide who, referring to the instinct of animals, spoke of that as a natural power undeveloped in man. Is it true that by mental cultivation a new sense can be evolved whereby darkness may become as light?" "Yes; that which you call light is a form of sensible energy to which the faculties of animals who live on the surface of the earth have become adapted, through their organs of sight. The sun's energy is modified when it strikes the surface of the earth; part is reflected, but most of it passes onward into the earth's substance, in an altered or disturbed condition. Animal organisms within the earth must possess a peculiar development to utilize it under its new form, but such a sense is really possessed in a degree by some creatures known to men. There is consciousness behind consciousness; there are grades and depths of consciousness. Earth worms, and some fishes and reptiles in underground streams (lower organizations, men call them) do not use the organ of sight, but recognize objects, seek their food, and flee from their enemies." "They have no eyes," I exclaimed, forgetting that I spoke to an eyeless being; "how can they see?"