A human being dies every second, or about 86,000 a day, and an equal number, or to speak more exactly, a little more than 86,000 are born daily. This figure, true for the nineteenth century, applies to a long period, if we increase it proportionately to the time. The population of the globe has increased from epoch to epoch. In the time of Alexander there were perhaps a thousand million living beings on the surface of the earth. At the end of the nineteenth century fifteen hundred million; in the twenty-second century two thousand million; in the twenty-ninth three thousand million; at its maximum the population of the globe had reached one hundred thousand million. Then it had begun to decrease. Of the innumerable human bodies which have lived, not one remains. All have been resolved into their elements, which have again formed new individuals. All that fills the passing day—labor, pleasure, grief and happiness—vanishes with it into oblivion. Time flies, and the past exists no longer; what has been, has disappeared in the gulf of eternity. The visible world is vanishing every instant. Only the invisible is real and enduring. During the ten million years of history, the human race, surviving generation after generation, as if it were a real thing, had been greatly modified from both a physical and moral point of view. It had always remained master of the world, and no new race had aspired to its sovereignty; for races do not come down from heaven or rise from hell; no Minerva is born full-armed, no Venus awakes full-grown in a shell of pearl on the seashore; everything grows, and the human race, with its long line of ancestry, was from the very beginning the natural result of the vital evolution of the planet. Under the law of progress, it had emerged from the limbo of animalism, and by the continued action of this same law of progress it had become gradually perfected, modified and refined. But the time had come when the conditions of terrestrial life began to fail; when humanity, instead of advancing, was itself to enter upon its downward path. The internal heat of the globe, still considerable in the nineteenth century, although it had ceased to have any effect upon surface temperature, which was maintained solely by the sun, had slowly diminished, and the earth had, at last, become entirely cold. This had not directly influenced the physical conditions of terrestrial life, which continued to depend upon the atmosphere and solar heat. The cooling of the earth cannot bring about the end of the world.