148 LIFE OF ELIE METCHNIKOFF 



and depression. ... In an ardent, stormy life such 

 as this, each year counted for many. 



As soon as he arrived at the Pasteur Institute 

 he undertook active researches with the object of 

 developing and defending the phagocyte theory. 



By experiments on the rouget of pigs he refuted 

 the objections of Emmerich, who affirmed that, in 

 that disease, the destruction of the microbes was not 

 due to phagocytes. By experiments on the anthrax 

 of pigeons he answered the attacks of Baumgarten 

 and his pupils. To Behring, who affirmed that 

 immunity was due to the bactericidal power of the 

 serum, he replied by a series of experiments on the 

 anthrax of rats. 



By all these researches Metchnikofi proved that 

 recovery and immunity depended on the absorp- 

 tion and digestion of living, virulent microbes by 

 phagocytes. Natural or artificial vaccination by 

 attenuated microbes allows the phagocytes to become 

 gradually accustomed to digest more virulent ones, 

 and this confers immunity upon the organism. That 

 phenomenon is comparable to that by which we can 

 accustom ourselves gradually to doses of poison which 

 would be very harmful if taken at the start (arsenic, 

 opium, nicotine, etc.). 



Little by little, the accuracy of MetchnikofTs obser- 

 vations began to be realised, and, moreover, other 

 scientists supported him by their personal investi- 

 gations. The part played by phagocytosis was 

 becoming more and more evident and the question 

 was ripening in France and in England, but in Ger- 

 many it still met with great opposition. 



At the Berlin Congress in 1890 the theory was 

 received very favourably by Lister, whilst Koch 



