" Remarkable for its simple language and clear 

 style, , , , Bears the stamp of a production of 

 an erudite scientist and a deep thinker," Science. 



TKe Prolongation of 

 Life 



Optimistic Essays 



By Elie MetcKniKoff 

 Author of "The Mature of Man/' etc. 



8vo. Price, $2.50 net 



M. lie Metchnikoff is one of those rare scientists who 

 have found a way to lay hold of and present to the world in 

 uutechnical phraseology, intelligible to the lay mind, such 

 results of his researches as are of universal interest and go 

 straight home to the bosoms and business of intelligent men. 

 The Nature of Man, by the same author, was one of the most 

 fascinating books, at once popular, and scientific, which have 

 appeared for decades. The book here in question will stand 

 beside it as a worthy companion volume. It is satisfactory 

 to report that, absorbed as Metchnikoff is in " material " 

 problems, and deep as he is in the mysteries of the physical 

 universe, these essays show him to be an optimist who speaks 

 with no uncertain voice. 



A great deal of attention is given in The Prolongation of 

 Human Life to the subject of old age and its causes, with 

 scientific observations of special cases among human beings 

 and the lower animals. The author suggests means of pro- 

 longing life and health, while contemplating natural death 

 with serenity, and finding that agreeable sensations accompany 

 its approach. Beyond a certain point it seems to him a dis- 

 advantage to prolong life. Passing on from these mortuary 

 lucubrations, the essays concern themselves with psychological 

 matters, with optimism and pessimism and in general with 

 questions of science and morals. The temperaments of certain 

 great men are analyzed in studies that have for their subjects 

 respectively Byron, Leopardi, Schopenhauer, and Goethe. In 

 the preface the author says that he has avoided, as far as 

 possible, repeating points which have been sufficiently treated 

 in The Nature of Alan. 



G. P. PUTNAM'S SONS 



NEW YORK LONDON 



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