Barnes has given a new and fresh point of view in general physiology. Since the publication of Bayliss's Principles of General Physiology, this is the first book in English to give a significantly improved approach. The author himself is a prolific contributor to the field of general physiology, especially in the fundamental problems of water metabolism, and his chapters on physical chemistry applied to physiology are especially valuable. Of 477 pages, 267 are devoted to such topics. There has not been a more intelligent or more comprehensive biologic treatment of these questions in any language. There is a large and valuable bibliography, and the book is well indexed. The illustrations are ingenious and many, particularly the diagrammatic ones, are original.