THEORIES OF IMMUNITY. 



of artificial procedures. If the 

 latter, it may be 

 Active: the result of the use of 



toxines, or 

 Passive: the result of the use of 

 autitoxiues. 

 Immunity unit : see antitoxine unit. 

 Inactivated: used especially to denote the de- 

 struction of the complement in an immune 

 serum by exposure to heat (55° C), thus 

 making the immune body inactive. 

 Infection: often applied to the action of the bac- 

 teria, as distinct from that of their toxines. 

 Intermediary body : see Immune body. 

 Intoxication : applied to the results of the action 

 of bacterial poisons as distinguished from 

 that of the bacteria themselves. 

 Isolysin: a substance produced artificially in 

 serum, capable of destroying the blood cor- 

 puscles of animals of the same species. 

 Isopathic immunity : term suggested by Behring 

 to indicate the immunity of the individual 

 cell (the condition he thinks probably ob- 

 tains in active immunity) ; immunity secured 

 by the use of toxines. 



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