After considering the objections to the use, or rather abuse, of hypnotism, I may add some further explanation of hypnotism itself--of its nature so far as it is known to science. Science has ascertained the reality of the phenomena and facts--not single facts only, scattered here and there, but groups of facts uniformly obedient to certain laws of nature. It has not yet discovered the exact cause or causes of all these phenomena, but it gives plausible explanations of them, both in the physical theory of the Paris School and in the psychical theory of the Nancy School of Physicians. Science has discarded the original theory of a mesmeric fluid as the cause of these phenomena, just as it has discarded the formerly supposed fluids of electricity and magnetism. Of electricity the "Century Dictionary" says: "A name denoting the cause of an important class of phenomena of attraction and repulsion, chemical decomposition, and so on, or, collectively, these phenomena themselves." The true nature of electricity is as yet not all understood, but it is not, as it was formerly supposed to be, of the nature of a fluid. Similarly we may define hypnotism as the collection of peculiar phenomena of a trance or sleep artificially induced, or the induced trance or sleep itself. The true cause of these phenomena is not yet understood, but there is no apparent reason for attributing them to a special fluid; they seem to be peculiar ways of acting, belonging to man's physical powers when his nerves are in an abnormal condition. By laying down these definite statements we gain the advantage that we isolate hypnotism from the frauds and empty shades, from the ghosts and hobgoblins with which it used to be associated in the border-region which we have undertaken to explore. Science deals with well-ascertained facts. Now of mesmerism, animal magnetism, and its kindred, odylism, we have seen that we have no reliable facts. We have done with those unsubstantial shades. But of hypnotism we have well-known facts, and we have shown it to be placed on a scientific basis. VIII. SCIENCE DREADS ERROR.