16.The Hygiene of Nerves and Mind in Health and Disease. By August Forel, M.D., formerly Professor of Psychiatry in the University of Zurich. Authorized Transla­tion. 8o.

A comprehensive and concise summary of the results of science in its chosen field. Its authorship is a guarantee that the statements made are authoritative as far as the statement of an individual can be so regarded.

17.The Prolonga­tion of Life. Optimistic Essays. By Élie Metchnikoff, Sub-Director of the Pasteur Institute. Author of “The Nature of Man,” etc. 8o. Illustrated. Net, $2.50. Popular Edi­tion. With an introduc­tion by Prof. Charles S. Minot.

In his new work Professor Metchnikoff expounds at greater length, in the light of addi­tional knowledge gained in the last few years, his main thesis that human life is not only unnaturally short but unnaturally burdened with physical and mental disabilities. He analyzes the causes of these disharmonies and explains his reasons for hoping that they may be counteracted by a ra­tional hygiene.

18.The Solar System. A Study of Recent Observa­tions. By Prof. Charles Lane Poor, Professor of Astronomy in Columbia University. 8o. Illustrated.

The subject is presented in untechnical language and without the use of mathematics. Professor Poor shows by what steps the precise knowledge of to-day has been reached and explains the marvellous results of modern methods and modern observa­tions.

19.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.

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.

20.Climate—Considered Especially in Rela­tion to Man. By Robert Decourcy Ward, Assistant Professor of Climatology in Harvard University. 8o. Illustrated.

This volume is intended for persons who have not had special training in the technicalities of climatology. Climate covers a wholly different field from that included in the meteorological text-books. It handles broad ques­tions of climate in a way which has not been attempted in a single volume. The needs of the teacher and student have been kept constantly in mind.