478 EDMUND GUENEY : hypotheses. And thus it is that, even as the old pre-scientific speculation sought a transcendental unity of things in such principles as water or fire, so even advanced science may occasionally do injustice to the immense variety of Nature, and, in the determination to formulate a law for some special department of facts, may seek and observe too exclusively the facts which can be made to square with the law. It would be hard to find a better instance of such over-simpli- fication than is afforded by the modern science of Hypnotism. For so short a span of existence, few sciences can have been so prolific in theories, presented often concurrently, and with little attempt at mutual refutation ; and the time has perhaps come when the experimental knowledge of the subject which is so rapidly advancing may be usefully supple- mented by a brief critical review of its theoretic vicissitudes. If such a review reveals how divergent have been the various paths which speculation has taken, and how one after another of them seems to leave this or that set of facts on one side, it may at least aid in defining the problems that actually remain. The facts of Hypnotism, it is needless to say, first became prominent in connexion with theories which science has with one voice rejected, finding nothing therein but absurd personal pretensions, and an ignorant jargon about forces and fluids. The facts themselves, however, were too indis- putable and extraordinary to be neglected ; and the first and most comprehensive theory of them, advanced in opposition to those of ' mesmeric ' influence and ' odic ' emanations, was that of suggestion and imagination. The singular mental phenomena which followed ' mesmeric ' manipulations were ascribed to a temporary suspension of the ' subject's ' inde- pendent powers of will and judgment, whereby both his beliefs and his conduct were left at the mercy of external suggestions. This was the theory crudely set forth exactly a century ago by the Commission of the French Academy of Sciences which was appointed to examine Mesmer's claims. Though presumably regarded by them as an explanation, it clearly contains no explanatory power whatever : it is simply a description (and, as we shall see later, a very imperfect one) of the particular mental condition which the 'subject's' actions suggest. The crucial question remains : If the doc- trine of a specific influence from the operator be rejected as outside the domain of natural law, what are the natural laws to which this peculiar mental condition can be referred? Above all, what is the law of its production ?
