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494 are called the “seat” of consciousness. Still, we may not say that their movements are consciousness. Consciousness is that psychosis in which other psychoses are unified. It has, indeed, been questioned whether or not there may be a spinal consciousness as well as a cerebral consciousness. It is not improbable that this exists in those creatures that are not provided with a brain. It appears, however, that the “seat” of consciousness is always the higher co-ordinating centre, and that, in the process of development, this is transferred to successively added increments of the evolving organism. If this be true, in man the inferior centres of the nervous system have been made the unconscious mechanism through which reflex and voluntary actions are mediated, while consciousness, in its full-orbed splendor, is possible only in the superior regions of the brain.

Recent investigations have made it appear probable that there may be more than one consciousness in the same brain. In his book on Les Maladies de la Personnalité, Ribot enumerates the types of what may be called the dissolution of personality, or the disruption of the unity of consciousness. They are as follows: — (1) Alienation, in which the consciousness of the body is completely changed. A new state serves as the basis of a new psychic life, or manner of feeling, perceiving, and thinking, whence results a new memory. The old life is reduced to an almost unconscious state and has become to the new consciousness an “alien,” a stranger, whom the new person does not even know. (2) The second type is characterized by an alternation of two personalities, sometimes designated as “double consciousness.” The two personalities are often completely ignorant of each other. The periods of the domination of each phase of consciousness vary in duration, but alternate at intervals, sometimes fixed and sometimes not. The phenomena resemble what we might expect if two souls dwelt in one body with alternating mastery, and in earlier times such cases were interpreted as the obsession of superhuman beings. It is