IMMUNITY 209 



Immunity is entirely a cellular function and the inherent 

 tincture of " vitalism " in the phagocytosis doctrine is unavoid- 

 able. 



" The final phagocytic reaction is represented by the physical 

 or physico-chemical processes in the digestion of microbes, 

 conducted with the help of cytases, and favoured by the 

 presence of immune bodies ; in the resistance to poisons the 

 phagocytes must also exert chemical influences. But before 

 these phenomena occur, the phagocytes present activities which 

 are purely biological ; such are the chemiotactic perceptions 

 and movements directed towards the threatened spot, the 

 engulfment of bacteria, and the absorption of toxins, and 

 finally the secretion of substances utilized in cellular digestion " 

 (Metchnikoff, L'Immunite, p. 590). 



