THEORIES OF IMMUNITY. 



Leucojyenia : absence or disappearance from a 

 part of all phagocytes or wandering cells; 

 occurs temporarily in intraperitoneal injec- 

 tions. (Metchnikoff.) 



Lysins : see Spermatolysin. 



Macrocytase : cytase derived from the macropha- 

 gocytes, and active in the destruction of 

 blood corpuscles (hemolysis). (Metchni- 

 koff.) 



Macrophagocytes : large mononuclear leucocytes 

 of the blood and of the endothelium, and 

 also, according to Metchnikoff, from the 

 large cells lining the sinuses of the lymph 

 glands and the sinuses of the spleen. 



Microcytase : cytase derived from the micropha- 

 gocytes, and concerned in the destruction of 

 bacteria. (Metchnikoff. ) 



Microphagocytes : polymorphonuclear leucocytes. 



Minimal lethal dose (M.L.D.): the amount of 

 any toxine necessary to kill a two hundred 

 and fifty gram guinea-pig in four days, after 

 subcutaneous injection. 



Passive immunity : more or less temporary im- 

 munity, the result of the use of the serum of 



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