The school of Nancy to-day enjoys the most extensive following, and may be said to represent the dominant trend of present study. One may fairly say that the present psychological study in this domain is the study of suggestion, one form, though only one form, of which is hypnotic suggestion. With the complete realization of the psychological significance of the hypnotic state, the fierce and adventurous struggle for existence of hypnotism may be said to terminate in its undisturbed adaptation to a scientific environment. XI The history of the antecedents of hypnotism is rich in suggestiveness. For the historian of the inductive sciences it illustrates the influence of the circumstances accompanying a discovery upon the status of the discovery itself; that the acceptance of a discovery depends more upon its logical concordance with current scientific conceptions, upon the manner of its demonstration, than upon the intrinsic content of what is demonstrated. It is as difficult in science as in real life to escape the influences of unfortunate associates; the interesting state which we now recognize as hypnosis was naturally discredited when it consorted with animal magnetism and the marvels of somnambulism, but was recognized when its credentials were expressed in intelligible physiological and psychological terms. For the historian of human error the story is equally significant. It illustrates again that the mental attitude essentially influences truth and error alike; that with all due allowance for ignorance, for faulty observation, for defective organization of knowledge, error was due, more than to any of these, to the lack of suitable concepts for the proper absorption and appreciation of the phenomena in their true significance. For lack of these there was misconception and oversight, and in their stead prepossession by notions of a wholly irrelevant character. Such notions were fostered by what we retrospectively recognize as pseudo-science; such was the fictitious animal magnetism, an entity never demonstrated, but supported only by a superficial analogical plausibility. They were fostered also by the activity of the marvel-loving impulse, which is unresponsive to the uniformities of nature, and favors mystic fable, while overlooking sensible fact. "Wer unmögliches geglaubt, könnt unmögliches verrichten." The special form of belief, the name of the system, the nature of the explanatory theory, seem almost accidental. Throughout all times, the same intense craving to overthrow the limitations of the human mind has been present, and has been satisfied by much the same beliefs and theories. Mesmerism harks back to astrology; prophets and seers have always existed; the mystery of the attractive force of the magnet for long made magnetism a most popular explanation of any obscure phenomena; the same performances that convinced the mesmerist of the existence of the magnetic fluid are evidence to the electro-biologist