LIFE OF ELIE METCHNIKOFF 185 



pounded in 1903 in his work, Etudes sur la nature 

 humaine. 



He considered " old age " as a pathological pheno- 

 menon. He saw in it one of the most important dis- 

 harmonies of human nature, because of the fact that 

 neither senility nor death is accompanied by a natural 

 instinct. The accomplishment of every physiological 

 function leads to satiety or to a desire for rest ; after 

 a busy day, man feels an instinctive need for rest and 

 sleep. But, in his maturity, he has no desire to grow 

 old, and in his old age none to die. It is rare that 

 one should aspire to die, and nobody wishes to grow 

 old. These facts are in contradiction with other 

 natural phenomena ; they are all the more discordant 

 that they play an immense part in our psychical life. 



After a general review of opinions on human nature, 

 Metchnikoff analysed it from the biological point of 

 view ; he revealed its discords and concluded that it 

 is far from being perfect. In his eyes, the lack of 

 harmony in the human being is an inheritance from 

 our animal ancestors ; they have handed down to us 

 a whole series of remains of organs which are not only 

 useless but even harmful in the new conditions of 

 human existence. 



The large intestine, inherited from mammalian 

 ancestors, holds the first place among those noxious 

 organs. This reservoir of food refuse was very useful 

 to our animal forebears in their struggle for existence ; 

 it allowed them not to interrupt their flight whilst 

 pursued by their enemies. In man, whose life condi- 

 tions are different, a large intestine of that size, 

 without offering the same advantages, is a source of 

 slow and continuous poisoning and a cause of prema- 

 ture senility and death. 



