The Mutation Theory. Experiments and Observations on the Origin of Species in the Vegetable Kingdom. 2 vols. Numerous illustrations, colored plates. By Hugo de Vries. Translated by Prof. A. B. Farmer and A. D. Darbishire. Cloth, per volume, $4.00. This is de Vries' great book on a new explanation of the evolution theory, accounting for the formation of species not by the struggle for existence but by mutation. Intracellular Pangenesis. Including a paper on Fertilization and Hybridization. By Hugo de Vries. Translated from the German by C. Stuart Gager. Cloth, $3.00 net. This is de Vries' first important book. It is not very large, but ought to be read by all students of botany, and also by those who are interested in the theory of evolution. On Orthogenesis and the Impotence of Natural Selection in Species-Formation. By Th. Eimer. Translated by T. J. McCormack. Price, paper, 30c net. Another critic of Darwin who claims that organisms develop through transmission of acquired characters. On the Inheritance of Acquired Characters. By Eugenio Rignano. Translated by Basil C. H. Harvey. With an Appendix "On the Mnemonic Origin and Nature of Affective Tendencies." Cloth, $3.00 net. Rignano calls his theory "centro-epigenesis" and is greatly influenced by Weismann. On Double Consciousness. Studies in Experimental Psychology. By Alfred Binet. Third edition. Pages, 93. Cloth, 50c net; paper, 20c net. "A most valuable contribution to this important subject which none of its students can afford to leave unread."--_Public Opinion._ The Psychic Life of Micro-Organisms. By Alfred Binet. Authorized translation. Pages, xii, 120. Cloth, 75c net; paper, 30c net. "He fortifies his theory by such a wealth of exact observation and experiments that the reader who follows his demonstration carefully can hardly fail of conviction."--_New York Tribune._ The Psychology of Reasoning. By Alfred Binet. Translated from the second French edition by Adam Gowans Whyte, B.Sc. Pages, 191. Cloth, 75c net; paper, 30c net. "Like everything that Dr. Binet writes, the subject is stated and expounded lucidly."--_The Lancet._ The Diseases of Personality. By Théodule Ribot. Authorized translation. Fourth edition. Pages, 157. Cloth, 75c net; paper, 30c. Contents: Introduction, Consciousness; Organic Disorders; Affective Disorders; Diseases of the Intellect; Dissolution of Personality. The Diseases of the Will. By Théodule Ribot. Authorized translation. Third edition. Pages, vi, 121. Cloth, 75c net; paper, 30c net. Contains chapters on impairments of the will and of voluntary attention, the realm of caprices, and extinction of the will. Essay on the Creative Imagination. By Théodule Ribot. Translated from the French by A. H. N. Baron, Fellow in Clark University. Cloth, gilt top. Pages, 357. $1.75 net. The motor nature of the constructive imagination.