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The Study of Man. By A. C. HADDON.

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The Groundwork of Science, By ST. GEORGE MIVART. $2.00
Rivers of North America. By ISRAEL C. RUSsell. $2.00
Earth Sculpture; or, The Origin of Land Forms.
By JAMES GEIKIE.

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The Basis of Social Relations. By DANIEL G. BRINTON. $2.00
Experiments on Animals. By STEPHEN PAGET.

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Infection and Immunity. By GEORGE M. STERNBERG. $2.00

17.

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Disease. By AUGUST FOrel.

The Prolongation of Life. By ÉLIE METCHNIKOFF. 18. The Solar System. By CHARLES LANE Poor. 19. Heredity. By J. ARTHUR THOMPSON, M.A.

Health and

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Age, Growth, and Death. By CHARLES S. MINOT. $2.50
The Interpretation of Nature. By C. LLOYD MORGAN. $1.25
Mosquito Life. By EVELYN GROESBEECK MITchell.

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Problems of Life and Reproduction. By M. HARTOG. $2.50
Problem of the Sexes. By J. FINOT.

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The Positive Evolution of Religion. By F. HARRISON. $2.00
The Science of Happiness. By J. FINOT.

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Genetic Interpretation. By JAMES MARK BALDWIN.
Mosquito Control in Panama. By J. A. LE PRINCE.
By JACQUES Loeb.

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THE

NATURE OF MAN

STUDIES IN OPTIMISTIC

PHILOSOPHY

BY

ÉLIE METCHNIKOFF

PROFESSOR AT THE PASTEUR INSTITUTE

THE ENGLISH TRANSLATION

EDITED BY

P. CHALMERS MITCHELL

M.A., D.Sc. Oxon.

SECRETARY OF THE ZOOLOGICAL SOCIETY
OF LONDON

The Francis A. Coun
Library of Riedicine

G. P. PUTNAM'S SONS
NEW YORK AND LONDON
The Knickerbocker Press