THEORIES OF IMMUNITY. 



denote the condition of resistance to further 

 injections of the infectious agent. 



Anti-sera : the sera of animals which have been 

 treated in such a way as to produce in them 

 substances antagonistic to various bodies ; 

 e.g., bacteria, toxines, blood-corpuscles, etc. 

 Most commonly used to denote antitoxic 

 sera. 



Antitoxic immunity : passive immunity. 



Antitoxine unit: the amount of immune serum 

 necessary to exactly neutralize one hundred 

 minimal lethal doses of toxine, after being 

 mixed one-half hour. 



Atom-groups : atoms of the molecule supposed 

 to have special affinities ; become recep- 

 tors. 



Autolysin: a substance in serum capable of dis- 

 solving the animal's own blood ; existence 

 not demonstrated. 



Bacteriolysis ; the breaking up of bacteria by 

 substances present in certain sera ; differ- 

 ing from proteolysis in that the bacteria 

 may not be dead. 



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