CHAPTER III. 



IMMUNITY. 



DnriNiiioN. 



IMPORTANCE. 

 VARlliTIES. 



Inherited, (Natural). 

 Definition. 

 B.rainl^lcs. 

 Cutise. 



Cell Action, (M etchnilcoff & .Sternberg). 

 Clicmic .Sul'staihc, i lilirlieli Sr Bneltner). 

 ACQUIRED, (Artificial). 

 Deiinilion. 

 E.vumples. 

 Varieties. 

 Active. 



Definition. 



I'arieties, (To.vic). (Bacterial). 



Etiology. 



Recovery jro)ii attack of disease. 

 Inoculation 'villi virus. 

 Inoculation ivitli "vaccine. 

 Inoculation with hacterin. 

 Inoculation luith to.rin. 



Iiiocntatiott simultaneously zvith virus and antibody. 

 Passive. 



Definition. 

 Etiology. 



Inoculation zvith antibodw 

 THEORIES. 



E.rhauslioii. 

 Retention. 

 Phagocytosis. 

 Humoral. 

 Ehrlich's Lateral Chain Theory. 



Immunity literally means proof ajjainst disease, i. e., it is 

 the name of the condition that enables an animal to resist the 

 action of pathogenic micro-organisms, or to be unaffected by 

 their products. Immunity is onlj' a relative term, the condition 

 is not absolute and permanent neither is it constant and con- 

 tinuous. Whenever an animal is unable to adjust itself to its 

 environments it becomes susceptible to the effects of the causa- 

 tive agents of diseases, i. e., its immunity, at least acquired 

 immunity, is suspended. 



The term immunity is ordinarilv used in reference to infec- 

 tive diseases, i. e. those diseases resulting from the invasion of 

 microparasitcs ; although it may be used in designating the 

 resistance to the action of zootoxin, such as snake venom, and 

 possibly also of the poisonous substances ejected bv centipedes 



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