THEORIES OF IMMUNITY. 



an animal already subjected to active immu- 

 nity (antitoxine immunity). 



Peritoneum : the French conception is " of a great 

 opened-out gland (un ganglion lymphatic 

 etale), whose cells have proliferative and 

 protective powers, and whose removal 

 renders an animal more susceptible to bac- 

 terial infection than usual." (Ritchie.) 



Pfeijfers reaction (or Phenomenon) : the disinte- 

 gration of bacteria resulting when these, 

 together with immune serum, are injected 

 into the peritoneal cavity of a fresh animal. 

 The starting point of all the recent work on 

 bacteriolysis, hemolysis, etc. 



Phagocytosis : the property possessed by certain 

 fixed and free ameboid cells of englobing 

 and digesting bacteria and other bodies. 

 Supposed by Metchnikoff to be derived from 

 the cells of the mesoderm. 



Phagolysis : partial or complete destruction of 

 phagocytes, used especially in connection 

 with intraperitoneal injections in Pfeifier's 

 phenomenon. (Metchnikoff.) 



Precipitines : substances found in the blood of 



an animal, after injection with blood of an- 

 us 



