The _Psychologie als Erfahrungs-Wissenschaft_ of _Hans Cornelius_ is not intended for a complete account and review of the facts of psychical life, but rather to present the fundamentals of a purely empirical theory, excluding all metaphysical views. Such an account should not start from any arbitrary abstractions or hypotheses, but simply from actually ascertained, directly perceived psychical experiences. On the other hand, an empirical definition should be required for all the terms that are used in a comprehensive description of the experience; and no term should be used without the psychical manifestation described by it being pointed out. After an introduction in which the method and place of psychology, subjective and objective, physiological and genetic, are referred to, the elementary facts of consciousness are discussed. The coherency of knowledge is treated of in the next chapter, and in the third, Psychical Analysis and the conception of unobserved consciousness; and the succeeding chapters are devoted to Sensation, Memory, and Fancy; The Objective World, Truth and Error, and Feeling and Will. (Published at Leipsic, Germany: B. G. Teubner.) An extremely interesting book is given us in the publications of the Wisconsin Geological and Natural History Society of studies by _George W._ and _Elizabeth Peckham_, of the _Instincts and Habits of the Solitary Wasps_. These insects are familiar enough to us all, as we meet them or see their nests of one or a few cells every day, and then think no more of them. But Mr. and Mrs. Peckham, following them to their haunts and keeping company with them, have found them manifesting remarkable instincts and exercising curious customs, which they describe in the style of persons who are in love with their work. The opportunity for the studies was given in two gardens, one on the top of a hill and the other lower down, with an island in a lake close by and acres of woodland all about, offering a rich variety of nesting places. There are more than a thousand species of these solitary wasps in the United States, to only about fifty of the social ones, and they live without knowledge of their progenitors and without relations with others of their kind.