CHAPTER III 

 THE GENERAL PHENOMENA OF IMMUNITY 



TYPES OF IMMUNITY. 



NATURAL IMMUNITY. 

 SPECIES. 

 RACIAL. 

 FAMILY. 

 INDIVIDUAL. 

 INHERITED IMMUNITY. 

 ACQUIRED IMMUNITY. 



NATURALLY ACQUIRED. 

 ARTIFICIALLY ACQUIRED. 



ACTIVE ARTIFICIALLY ACQUIRED. 



INOCULATION OF LIVING VIRUS IN HEALTH. 

 USE OF ATTENUATED VIRUS. 

 USE OF DEAD BACTERIA. 

 USE OF BACTERIAL PRODUCTS. 

 PASSIVE ARTIFICIALLY ACQUIRED. 

 THEORIES OF THE NATURE OF IMMUNITY. 

 THE EHRLICH SIDE-CHAIN THEORY. 

 THE EHRLICH CLASSIFICATION OF IMMUNE BODIES. 

 CRITICISM OF THE EHRLICH HYPOTHESIS. 

 THE SPECIFICITY OF IMMUNE REACTIONS. 



NON-SPECIFIC THERAPY OF INFECTIOUS DISEASES. 

 THE SITE OF ANTIBODY FORMATION. 



PRODUCTION OF ANTIBODIES AT SITE OF INJECTION. 



Types of Immunity. Resistance to disease may be natural or 

 acquired. If natural it may be of a species, race, family, or indi- 

 vidual character. If acquired it may be naturally acquired, as seen 

 in the immunity following an attack of infectious disease, or it may 

 be artificially acquired. If artificially acquired it may be the result 

 of active immunization or of passive immunization. Artificially 

 acquired active immunity is such as may follow the injection of 

 various antigens, such as toxins, bacteria, and numerous other sub- 

 stances. Artificially acquired passive immunity is the result of 

 transfer of active immunity from an immune animal to a normal 

 animal, which latter becomes passively immunized. 



Natural Immunity. Although the term immunity may be consid- 

 ered as equivalent to the capacity for resisting disease, nevertheless, 

 in common usage it often implies an increase of resistance. In esti- 

 mating an increase of resistance a normal degree must be presup- 

 posed and the determination of the normal is extremely difficult. 

 In considering natural immunity the term is used in contrast to sus- 

 ceptibility and is not comparable to a normal level of resistance. 

 Natural resistance to disease is favored by structure, movement, 

 fluids, and secretions of the body. Structurally the skin is practi- 

 cally impermeable to bacteria. In a general way this is true of 

 mucous membranes, although we know that certain organisms may 

 pass through mucous membranes of the intestinal tract without any 

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