This epoch marked the apogee of the human race. Thenceforward the conditions of life grew less favorable, and from century to century, from generation to generation, underwent marked change. Vegetable and animal species, the human race itself, everything in short, became transformed. But whereas, hitherto, these metamorphoses had enriched, embellished and perfected life, the day had come when decadence was to begin. During more than a hundred thousand years it was insensible, for the parabolic curve of life did not suddenly fall away from its highest point. Humanity had reached a degree of civilization, of intellectual greatness, of physical and moral well-being, of scientific, artistic and industrial perfection, incomparably beyond anything of which we know. For several million years the central heat of the globe had been utilized in winter for general warming purposes by towns, villages, manufactories and every variety of industry. When this failing source of heat had finally become exhausted, the heat of the sun had been stored subject to the wants of the race, hydrogen had been extracted from sea-water, the energy of waterfalls, and subsequently that of the tides, had been transformed into light and heat, and the entire planet had become the plaything of science, which disposed at will of all its elements. The human senses, perfected to a degree which we should now qualify as supernatural, and those newly acquired, mentioned above, become with the lapse of time more highly developed; humanity released more and more from the empire of matter; a new system of alimentation; the spirit governing the body and the gross appetites of former times forgotten; the psychic faculties in perpetual play, acting at a distance over the entire surface of the globe, communicating under certain conditions with even the inhabitants of Mars and Venus; apparatus which we cannot imagine replacing those optical instruments with which physical astronomy had begun its investigations; the whole world made new in its perceptions and interests; an enlightened social condition from which envy and jealousy, as well as robbery, suffering and murder had disappeared—this, indeed, was a real humanity of flesh and bone like our own, but as far above it in intellectual supremacy as we are above the simians of the tertiary epoch.