LIFE OF ELIE METCHNIKOFF 281 



Eesearches on the silk-worm moth — a rare ex- 

 ample of an animal the life of which ends in natural 

 death — allowed him to conclude that the latter is 

 due to an auto -intoxication of the organism. 



But he only just raised the veil of the great 

 mystery ; it was his last work. . . . 



MetchnikofE's philosophical evolution ran on 

 parallel lines with his scientific researches. 



When studying the laws and the unity of vital 

 phenomena he found that their harmony was occa- 

 sionally broken by the collision of internal conditions 

 with the environment and that regrettable conse- 

 quences ensued. He saw an example of that in human 

 nature, full of disharmonies due to its animal origin. 



These considerations caused the pessimism of his 

 youth. But his energetic, pugnacious temperament 

 could not remain content with a passive acceptance 

 of facts. 



He started to study the lack of harmony in human 

 nature and its causes, and sought for means to combat 

 these causes. Gradually he reached the conclusion 

 that the greatest human disharmonies are provoked 

 by the rupture of the normal cycle of our life, by the 

 precocity of senility and of death, chiefly arising from a 

 chronic poisoning by the toxins of intestinal microbes. 



But having acquired the conviction that it is 

 possible to struggle against that intoxication, he con- 

 cluded that science, which has already done so much 

 to fight diseases, would also find means of struggling 

 against premature old age and precocious death, thus 

 leading us to the normal vital cycle, orthobiosis. 



Then disharmony, transformed into harmony, will 

 cause the greatest of ills to disappear. 



