318 INFECTION AND IMMUNITY. 



agglutinating, fall away into the background in 

 such examples of immunity." It is the tendency 

 of the school of Metchnikoif to refer the protective 

 power of a serum to its faculty of stimulating the 

 phagocytes rather than to its effect on the micro- 

 organisms. We shall see, however, in speaking of 

 opsonins (p. 324) that even in relation to anthrax 

 the serum may possess a distinct property which 

 facilitates phagocytosis, not by stimulating the 

 phagocytes but by some action on the bacteria. 

 cholera and Concerning those diseases in which immunity 

 infection*! is characterized by a great increase of the bac- 

 tericidal amboceptors or fixators, Metchnikoff does 

 not disregard the existence or importance of the 

 immune bodies, but rather seeks to show that they 

 are a product of phagocytic activity. The con- 

 ditions are held to be similar to those already 

 mentioned in connection with intra vitam hemoly- 

 sis. That is to say, microcytase exists only in the 

 leucocytes of the immune animal under normal 

 conditions; it escapes into the plasma, or into the 

 serum during coagulation, only as a consequence 

 of the phagolysis already mentioned. The phe- 

 nomenon of Pfeiffer occurs only because the in- 

 jected culture injures the leucocytes, resulting in 

 the liberation of microcytase, which in conjunction 

 with the fixators causes the solution of the vibrio. 

 When phagolysis is prevented by a preceding in- 

 jection of bouillon, phagocytosis and intracellular 

 solution of the organisms entirely supplant extra- 

 cellular solution. 



inti-H vnscuinr ^ an immune animal receives an intravascular 

 phagocytosis i n j ec tion of the vibrio of cholera and is sacrificed 

 shortly, the relation of the organisms to the leu- 



