278 LIFE OF ELIE METCHNIKOFF 



of the higher animals ; thus his phagocyte theory 

 was born. 



Seeing that unicellular beings, like the mobile cells 

 of Metazoa, englobe, not only food, but foreign 

 bodies, he asked himself whether this was not at 

 the same time a defensive action. Such a possi- 

 bility brought no surprise to a zoologist, accustomed 

 to see that, in the struggle for existence, animals 

 often devoured their enemies. 



All the materials for the building up of the phago- 

 cyte theory were therefore ready in MetchnikofFs 

 mind when he asked himself, as by an intuition, 

 whether the white globules of our blood, globules 

 so similar to amoebae, do not play the part of a 

 defensive army in our organism when they envelope 

 in accumulated masses intrusive bodies injurious to 

 the organism. 



The thought was but the result of a preparatory 

 work already accomplished ; it was the butterfly 

 escaping out of the chrysalis. 



MetchnikofE had recourse to his method of simpli- 

 fication in order to solve the question. 



The organism of the higher animals being ex- 

 tremely complicated, he went down as far as the 

 transparent larva of the starfish (bipinnaria) in order 

 to watch with his own eyes the phenomena which 

 take place within it. He introduced a rose-thorn 

 into the transparent body of the larva, and noted 

 the next day that the mobile cells in the latter had 

 crowded towards the splinter, like an army rushing 

 to meet a foe. 



The analogy of this phenomenon with inflamma- 

 tion and the formation of an abscess was striking. 

 Metchnikoff said to himself that since most diseases 



