been kept constantly in mind.

+20.--Heredity.+ By J. ARTHUR THOMSON, M.A., Professor of Natural
History in the University of Aberdeen; Author of "The Science of
Life," etc. 8o. Illustrated. Net, $3.50.

The aim of this work is to expound, in a simple manner, the facts of
heredity and inheritance as at present known, the general conclusions
which have been securely established, and the more important theories
which have been formulated.

+21.--Age, Growth, and Death.+ By CHARLES S. MINOT, James Stillman
Professor of Comparative Anatomy in Harvard University,
President of the Boston Society of Natural History, and Author
of "Human Embryology," "A Laboratory Text-book of Embryology,"
etc. 8o. Illustrated.

This volume deals with some of the fundamental problems of biology,
and presents series of views (the results of nearly thirty years of
study), which the author has correlated for the first time in
systematic form.

+22.--The Interpretation of Nature.+ By C. LLOYD MORGAN, LL.D.,
F.R.S. Crown 8vo. Net, $1.25.

Dr Morgan seeks to prove that a belief in purpose as the causal
reality of which nature is an expression is not inconsistent with a
full and whole-hearted acceptance of the explanations of naturalism.

+23.--Mosquito Life.+ The Habits and Life Cycles of the Known
Mosquitoes of the United States; Methods for their Control;
and Keys for Easy Identification of the Species in their Various
Stages. An account based on the investigation of the late James
William Dupree, Surgeon-General of Louisiana, and upon the
original observations by the Writer. By EVELYN GROESBEECK
MITCHELL, A.B., M.S. With 64 Illustrations. Crown 8vo.
Net, $2.00.

This volume has been designed to meet the demand of the constantly
increasing number of students for a work presenting in compact form
the essential facts so far made known by scientific investigation in
regard to the different phases of this, as is now conceded, important
and highly interesting subject. While aiming to keep within reasonable
bounds, that it may be used for work in the field and in the
laboratory, no portion of the work has been slighted, or fundamental
information omitted, in the endeavor to carry this plan into effect.

+24.--Thinking, Feeling, Doing.+ An Introduction to Mental Science.