THE first of these two works on the psychology of Protozoa is disappointing. Its main object, as indicated in its title, is to investigate the claims which from time to time have been put forward on behalf of unicellular organisms to the possession of consciousness and a certain low order of mental life. Therefore, looking to the position which M. Binet has gained as a successful worker in other departments of psychological inquiry, we were prepared at his hands to meet with a judicious treatment of facts in the light shed by a specially instructed mind. But, far from this, what we do meet with is the special pleading of an advocate who seems to hold a brief on behalf of his little friends, and is determined to force them into a position of intellectual prominence, no matter at what cost of psychological absurdity. Indeed, were it not that the title-page declares the authorship of this work, no one could possibly have supposed that it had been written by a man who had ever opened an elementary text-book on mental science. The Psychic Life of Micro-organisms: a Study in Comparative Psychology. By Alfred Binet. Translated from the French by Thomas McCormack. (Chicago: The Open Court Publishing Company, 1889.) Psycho-physiologische Protisten-Studien: experimentelle Untersuchungen. Von Dr. Max Verworn. (Jena: Gustav Fischer, 1889.)