LIFE OF ELIE METCHNIKOFF 187 



useful microbes ; the struggle against infectious 

 diseases and alcoholism — all these are workable means 

 of fighting pathological and premature senility. 



When old age becomes physiological and no longer 

 painful it will become proportionate with the other 

 epochs of our lives and cease to alarm us. But how 

 is the fear of death to be explained, since it is a general 

 and inevitable phenomenon ? How is it that we have 

 no natural instinct for death ? MetchnikofE supposes 

 that this lack of harmony in our nature comes from 

 the fact that death is as premature as senility and 

 arrives before the natural instinct for it has had time 

 to develop. This supposition is confirmed by the 

 fact that old people who have reached an excep- 

 tionally advanced age are often satiated with life 

 and feel the need of death as we feel a need of sleep 

 after a long day's work. That is why we have a 

 right to suppose that, when the limit of life has been 

 extended, owing to scientific progress, the instinct of 

 death will have time to develop normally and will 

 take the place of the fear which death provokes at 

 the present day. Both death and old age wiU become 

 physiological and the greatest discord in our nature 

 will be conquered. 



Our manner of life will have to be modified and 

 directed according to rational and scientific data if 

 we are to run through the normal cycle of life — ortho- 

 biosis. The pursuit of that goal will even influence 

 the basis of morals. Orthobiosis cannot be accessible 

 to all until knowledge, rectitude, and solidarity 

 increase among men, and until social conditions are 

 kinder. 



Man will then no longer be content with his natural 

 inheritance ; he will have to intervene actively in 



