After he is gone? Will he then some day be gone, and this planet know him no more? Is it thither that the human drift in all its totality is trending? God Himself is silent on this point, though some of His prophets have given us vivid representations of that last day when the earth shall pass into nothingness. Nor does science, despite its radium speculations and its attempted analyses of the ultimate nature of matter, give us any other word than that man will pass. So far as man's knowledge goes, law is universal. Elements react under certain unchangeable conditions. One of these conditions is temperature. Whether it be in the test tube of the laboratory or the workshop of nature, all organic chemical reactions take place only within a restricted range of heat. Man, the latest of the ephemera, is pitifully a creature of temperature, strutting his brief day on the thermometer. Behind him is a past wherein it was too warm for him to exist. Ahead of him is a future wherein it will be too cold for him to exist. He cannot adjust himself to that future, because he cannot alter universal law, because he cannot alter his own construction nor the molecules that compose him. It would be well to ponder these lines of Herbert Spencer's which follow, and which embody, possibly, the wildest vision the scientific mind has ever achieved: "Motion as well as Matter being fixed in quantity, it would seem that the change in the distribution of Matter which Motion effects, coming to a limit in whichever direction it is carried, the indestructible Motion thereupon necessitates a reverse distribution. Apparently, the universally-co-existent forces of attraction and repulsion, which, as we have seen, necessitate rhythm in all minor changes throughout the Universe, also necessitate rhythm in the totality of its changes--produce now an immeasurable period during which the attractive forces predominating, cause universal concentration, and then an immeasurable period during which the repulsive forces predominating, cause universal diffusion--alternate eras of Evolution and Dissolution. _And thus there is suggested the conception of a past during which there have been successive Evolutions analogous to that which is now going on; a future during which successive other Evolutions may go on--ever the same in principle but never the same in concrete result_."