This book is expressly designed to help the general student obtain a comprehensive grasp of the principles of biology.

Comstock——Handbook of Nature-Study

By ANNA BOTSFORD COMSTOCK, Lecturer in Nature-Study in Cornell University. Cloth 8vo. XVIII.+938 pages, more than 1,000 illustrations. Prices, postpaid: Bound in one volume, $3.65; bound in two volumes, $4.50; Volume I., including Animal Life, $2.25; Volume II., including Plant Life, $2.25. Sample pages sent on application.

A handbook of Nature-Study for teachers and parents, based on the Cornell Nature-Study Leaflets, with much additional material and many new illustrations.

The Comstock Publishing Company
Cornell Heights, Ithaca, N. Y.

Bausch & Lomb Optical Co.

154 Sutter Street

San Francisco, California

Factories: Rochester, N. Y. and Frankfort, a/M, Germany