—————————————————————————————————————————————————————— Transcriber’s Note: The position of the footnote anchor 171 at page 229 is a guess of the transcriber as the anchor was missing in the original book. —————————————————————————————————————————————————————— THE PROLONGATION OF LIFE OPTIMISTIC STUDIES BY ÉLIE METCHNIKOFF SUB-DIRECTOR OF THE PASTEUR INSTITUTE, PARIS THE ENGLISH TRANSLATION EDITED BY P. CHALMERS MITCHELL M.A., D.SC. OXON., HON. LL.D., F.R.S. _Secretary of the Zoological Society of London; Corresponding Member of the Academy of Natural Sciences of Philadelphia_ G. P. PUTNAM’S SONS NEW YORK & LONDON The Knickerbocker Press 1908 EDITOR’S INTRODUCTION Élie Metchnikoff has carried on the high purpose of the Pasteur Institute by devoting his genius for biological inquiry to the service of man. Some years ago, in a series of Essays which were intended to be provocative and educational, rather than expository, he described the direction towards which he was pressing. I had the privilege of introducing these Essays to English readers under the title _The Nature of Man_, a Study in Optimistic Philosophy. In that volume, Professor Metchnikoff recounted how sentient man, regarding his lot in the world, had found it evil. Philosophy and literature, religion and folk-lore, in ancient and modern times have been deeply tinged with pessimism. The source of these gloomy views lies in the nature of man itself. Man has inherited a constitution from remote animal ancestors, and every part of his structure, physical, mental and emotional, is a complex legacy of diverse elements. Possibly at one time each quality had its purpose as an adaptation to environment, but, as man, in the course of his evolution, and the environment itself have changed, the old harmonious intercourse between quality and circumstances has been dislocated in many cases. And so there have come into existence many instances of what the Professor calls “disharmony,” persistences of structures, or habits, or desires that are no longer useful, but even harmful, failures of parallelism between the growth, maturity and decay of physical and mental qualities and so forth. Religions and philosophies alike have failed to find remedies or efficient anodynes for these evils of existence, and, so far, man is justified of his historical and actual pessimism.