120 LIFE OF ELIE METCHNIKOFF 



mobile cells. In those observations he was delighted 

 to have found an example of physiological inflam- 

 mation, i.e. one which presented itself in normal and 

 non-morbid conditions. He thought he might observe 

 it also during the metamorphosis of the tadpole into 

 a frog, whilst the tail was being atrophied. But he 

 found that, instead of the leucocytes of the blood, 

 certain cells from the muscular tissue were those which 

 devoured the enfeebled elements of the tail ; he thus 

 learnt that phagocytes might be, not only the white 

 blood corpuscles, but other cells of mesodermic origin.^ 



In autumn 1883 he read his first paper on phago- 

 cytosis to a congress of physicians and naturalists at 

 Odessa.^ He compared the phagocytes to an army 

 hurling itself upon the enemy and looked upon the 

 phagocytic reaction as a defensive force of the 

 organism. 



In that paper itself and from that moment onwards, 

 the trend of his ideas towards optimism becomes visible. 

 By discovering the phagocytic reaction of the organ- 

 ism, he made a first breach in his philosophy of human 

 nature, hitherto so pessimistic ; he discovered within 

 it a salutary element which could be utilised by 

 science to combat its discords. He began to have 

 some faith in the power of knowledge, not only for 

 this struggle, but also for the establishment of a 

 rational conception of life in general. Thus he said 

 in his paper to the Odessa Congress : 



The theoretical study of Natural HistDiy problems (in 

 the largest sense of the word) alone can provide a critical 



1 It was only in 1892 that he completed and developed his observations. 

 He found that the cells of the sarcoplasma of the muscular tissue devoured 

 its contractile part, the myoplasma, 



2 This paper was entitled " Forces curatives de I'organisme." 



