THEORIES OF IMMUNITY. 



Hemolysis : breaking up of red corpuscles, see 

 lysins. Three factors are necessary for the 

 production of the phenomenon: 1, red-blood 

 corpuscles to be acted upon ; 2, a body oc- 

 curring in the serum of immune animals 

 and resisting heat up to (35° C, i.e., the im- 

 mune body ; 3, a body not resisting heat 

 above 55° C, and occurring in the blood 

 of a fresh animal, i.e., the complement. 



K Horror autotoxicus"' : Ehrlich's expression for 

 the fact that the tissues seldom, if ever, pro- 

 duce antibodies to receptors already exist- 

 ing in them. 



Immune body : exists in the serum of an immu- 

 nized animal; resists one-half hour at 75° 

 C; has two haptophorous atom-groups, one 

 satisfied by a receptor in the cell binding 

 tli em together, the other satisfied by a 

 receptor in the complement binding these 

 two together. 



Immunity: Natural, exists in many animals to 

 many infections diseases. 

 Acquired, may be the result of an 

 attack of a disease, or the result 



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