THIS is regarded in many universities as a standard text-book for the student's own reading. It givea the zoologist the necessary essentials of botany, and shows an understanding of the part played by unicellular organisms. The diagrams are simple and admirably selected, many being original. Technical terms are reduced to a minimum, and the student is helped also by an admirable glossary. The new edition is a great improvement, and the more adequate discussion of many themes will make them simpler to the student. The enlargement of the section devoted to human welfare is useful. We ourselves are rather tired of th,e evolution of the horse; in the next edition the author should explain what a horse is and how it is adapte to its environment, for his students will not know.
Foundations of Biology.
. Fourth edition. Pp. xvi + 501. (New York: The Macmillan Co., 1930.) 3.50 dollars.