President _D. S. Jordan's Footnotes to Evolution_[61] is made up of popular essays or addresses on the general subject of organic evolution which were given originally as oral lectures before University Extension Societies. Three of them have been also published in this Monthly, and as many in another magazine. Besides the author's own twelve essays, he has inserted in this volume three other papers of special importance, setting forth the present state of knowledge concerning the methods of evolution and of heredity. These are on the Factors of Organic Evolution as displayed in the Process of Development, by Prof. E. G. Conklin; the Physical Basis of Heredity, by Prof. F. M. McFarland; on The Testimony from Paleontology, by Prof. J. P. Smith. President Jordan's own essays begin with a discussion of the kinship of life. This is followed by three articles on evolution, relating to its nature, elements, and factors from the point of view of embryology, and an application of the subject in the paper on The Heredity of Richard Roe, in which the rise of race types from the survival of the existing race with its best results modified and preserved by the survival of the fittest is illustrated. In the seventh essay certain facts of animal distribution as related to the origin of species are considered; in the eighth (Latitude and Vertebrata) the curious biological problem of the possession of more numerous vertebræ by northern than by tropical fishes is considered--a problem the solution of which on any other hypothesis than that of the derivation of species would be impossible. The evolution of mind is then taken up as the sum total of all psychic changes, actions, and reactions, and this development is extended to nations the laws of whose greatness "expand themselves from the laws which govern the growth of the single cell." In the essay on Degeneration a lesson is drawn in favor of individual initiative. Hereditary Inefficiency is discussed in view of the danger from pauperism. Some of the aspects of the woman question are considered in another of the essays. In the paper on The Stability of Truth some recent enunciations of Lord Salisbury, Mr. Balfour, and Haeckel respecting science are criticised. The last essay is on The Struggle for Realities, and concerns the relations of science and conservatism, the Church, etc. [Footnote 61: Footnotes to Evolution. By David Starr Jordan. With Supplementary Essays by Edwin Grant Conklin, Frank Mace McFarland, and James Perrin Smith. New York: D. Appleton and Company. Pp. 392. Price, $1.]