By Oscar Schmidt, Professor in the University of Strasb irg.

With 26 Woodcuts. I vol., 12mo. Cloth.........Price, $1.50.

"The entire subject is discussed with a freshness, as well as an elaboration of detail, that renders his work interesting in a more than usual degree. The facts upon which the Darwinian theory is based are presented in an effective manner, conclusions are ably defended, and the question is treated in more compact and available style than in any other work on the same topic that has yet appeared. It is a valuable addition to the 'International Scientific Series.'" - Boston Post.

"The present volume is the thirteenth of the 'International Scientific Series,' and is one of the most interesting of all of them. The subject-matter is handled with a great deal of skill and earnestness, and the courage of the author in avowing his opinions is much to his credit. This volume certainly merits a careful perusal." - Hartford Evening Post.

"The volume which Prof. Schmidt has devoted to this theme is a valuable contribution to the Darwinian literature. Philosophical in method, and eminently candid, it shows not only the ground which Darwin had in his researches made, and conclusions reached before him to plant his theory upon, but shows, also, what that theory really is, a point upon which many good people who talk very earnestly about the matter are very imperfectly informed." - Detroit Free Press.