Under the general head of trance may be grouped all that class of cases in which the objective faculties are, for the time being, held in practically complete abeyance, and the subjective mind becomes correspondingly active. Various names have been applied to this condition, such as somnambulism, hypnosis, mesmeric trance, ecstasy, catalepsy, obsession, etc., many of the names implying a theory of causation rather than distinctive features of condition. The condition varies in accordance with the idiosyncrasies of the individual as much as from the causes which induce it. The leading characteristics are, however, the same in all cases. These are, first, the partial or complete abeyance of the objective mind; second, the activity of the subjective mind; and, third, the perfect amenability of the latter to control by the power of suggestion. Many remarkable mental phenomena are developed in these states, but this discussion will be confined to the supposed power of persons in the condition of trance to hold intercourse with the spiritual world. This power has been held to exist from time immemorial; the ancient and modern mystical literature is filled with the most interesting, not to say startling, accounts of interviews held by these persons with the inhabitants of the spirit-land. Vast systems of religion have been founded upon the supposed revelations of persons in a trance, and untold millions of the human race base their hopes of a life in a future world upon the dreams of ecstatics. The whole vast fabric of Oriental philosophy and religion is based upon the revelations of persons in a trance. The Swedenborgian philosophy in the Western world is founded upon the dreams of a person who, in a condition of a trance, believed himself to be able to hold familiar converse with the inhabitants of heaven and of hell. Some of these systems of spiritual philosophy are of such vast and complicated structure that the mind is wrapped in wonder and admiration of their magnitude and perfection. The Oriental philosophy, in particular, is so symmetrical, so pervaded by grand and noble conceptions, so permeated with lofty precepts of morality, humanity, and religion, that we are wont to lose sight of the fact that the whole structure is built up by a process of deductive reasoning from premises that have no better foundation than the dreams of ecstatics. But we are told that it has stood the test of thousands of years of thought and investigation, and that no fact in physical science can be adduced to disprove its fundamental principles. Doubtless this is true. The adepts have steered clear of propositions in physical science which could be disproved by the learning of the schoolboy. In this they have avoided those errors of the Bible of the Christians, which, though unimportant in themselves, having no bearing upon the real philosophy of the Christian religion, have proved a stumbling-block to superficial minds. But does it follow