LIFE OF ELIE METCHNIKOFF 117 



some extraordinary performing apes, I remained alone with 

 my microscope, observing the life in the mobile cells of a 

 transparent star-fish larva, when a new thought suddenly 

 flashed across my brain. It struck me that similar cells 

 might serve in the defence of the organism against intruders. 

 Feeling that there was in this something of surpassing interest, 

 I felt so excited that I began striding up and down the room 

 and even went to the seashore in order to collect my thoughts. 



I said to myself that, if my supposition was true, a splinter 

 introduced into the body of a star-fish larva, devoid of bloodv 

 vessels or of a nervous system, should soon be surrounded by 

 mobile cells as is to be observed in a man who runs a splinter 

 into his finger. This was no sooner said than done. 



There was a small garden to our dwelling, in which we had 

 a few days previously organised a " Christmas tree " for the 

 children on a little, tangerine tree ; I fetched from it a few 

 rose thorns and introduced them at once under the skin of 

 some beautiful star-fish larvae as transparent as water. 



I was too excited to sleep that night in the expectation of 

 the result of my experiment, and very early the next morning 

 I ascertained that it had fully succeeded. 



That experiment formed the basis of the phagocyte theory, 

 to the development of which I devoted the next twenty-five 

 years of my Ufe. 



"This very simple experiment struck Metchnikofi 

 by its intimate similarity with the phenomenon which 

 takes place in the formation of pus, the diapedesis ^ 

 of inflammation in man and the higher animals. The 

 white blood corpuscles, or hwiocytes, which consti- 

 tute pus, are mobile mesodermic cells. But, while 

 with higher animals the phenomenon is complicated 

 by the existence of blood-vessels and a nervous 

 system, in a star-fish larva, devoid of those organs, 

 the same phenomenon is reduced to the accumulation 



^ Migration of the white blood corpuacWs (leucocytes) through the walls 

 of blood-vessels. 



