In the present work, the accomplished director of the laboratory of physiological psychology at the Sorbonne has brought together and systematised all the most reliable phenomena bearing on one of the most curious subjects of inquiry now engaging attention. Notwithstanding the disagreement between different experimenters as to particular facts, all have arrived at the conclusion that, under special conditions, the normal unity of consciousness may be broken, and that then there is the production of several distinct consciousnesses “each of which can have its perceptions, its memory, and even its moral character.” No one is better fitted than M. Binet to perform the eclectic work he has undertaken of discussing the recent researches on the alteration of personality, without regard to the special views of particular schools. The subject is considered by him under the three heads of Successive Personalities, Coexisting Personalities, and The Alterations of Personality in the Experiences of Suggestion. The two first parts deal chiefly with phenomena presented by somnambulic and hysteric subjects. In the third part M. Binet applies the fact of the duplication of personality to the explanation of the phenomena of spiritism, the term he very properly gives to so-called spiritualism. He regards the supposed spirit agent as the subconscious personality of the medium acting under the influence of suggestion, a view which undoubtedly meets most of the actual facts of spiritism. Notwithstanding the divisibility of the ego, there can be no doubt of the unity of the personality under normal conditions. The question is as to the nature of this unity, and the author follows M. Ribot in affirming that it consists in the coördination of the elements which compose it. He repudiates the idea that memory is the sole foundation of consciousness, as not only may one memory embrace different states, but the same individual may have several memories, several consciousnesses, and several personalities. For the opinion of M. Binet on other points we must refer our readers to the work itself, which forms an important addition to the International Scientific Library. Ω. L’HOMME DANS LA NATURE. By _Paul Topinard_. With 101 Illustrations in the text. Paris: Félix Alcan. 1891. Pp. 350. Price, 6 fr.