CONTENTS ix 
III. Theories of Immunity 120 
A. The Humoral Side-chain or Ehrlich Theory of Immunity . 121 
Side-chains of the First Order 123 
Side-chains of the Second Order 124 
Side-chains of the Third Order 126 
B. The Cellular or Phagocj^tic Theory of Immunity 128 
CHAPTER VII. 
Anaphyl.\xis, Allergy or Hypersensitiveness. 
Sensitization 133 
Reinjection of the Homologous Protein 134 
Anaphylaxis 136 
The Nature of the Anaphylactic Reaction 136 
The Nature of the Anaphylatoxin 138 
Antianaphylaxis 138 
Theories 139 
Anaphylaxis in Man 142 
Natural Hypersensitiveness 142 
Artificial or Acquired Hypersensitiveness 143 
Practical and Theoretical Considerations 145 
CHAPTER VIII. 
Antigens and the Technique of Serum Reactions. 
Nature of Antigens and Antibodies 146 
Agglutinins. Agglutinoids and Proagglutinoids 147 
Preparation of Specific Agglutinating Sera 149 
Properties of Agglutinins 149 
Specificity of Aggkitination Reactions: Group Agglutinins .... 150 
Non-agglutinable Bacteria ; 151 
The Reaction of Agglutination 151 
1. Microscopic Method 152 
2. Macroscopic Method 153 
Precipitins. Precipitinoids 153 
Lysins 155 
MultipUcity of Amboceptors and Complement 158 
Fixation of Complement 158 
The Determination of Specific Antibodies by the Method of Comple- 
ment-fixation 159 
The Technique of Complement-fixation 160 
The Wassermann Serum Diagnosis of SyphiHs 160 
Complement-fixation in Bacterial Infections 167 
The Kahn Test in the Diagnosis of Syphihs 170 
Concentration of Precipitation Mixture 170 
Choice of an Antigen 171 
Instability of the Antigen Suspension 171 
Quantitative Relation Between Antigen Suspension and Serum . 171 
Shaking of the Ingredients 172 
Apparatus 172 
Reagents 172 
Standardization of Antigen • 174 
Titration of Antigen 174 
Determination of Antigen Sensitiveness 175 
Correction of Antigen 175 
Serum 176 
Physiological Salt Solution 178 
Routine Diagnostic Test With Serum 178 
Preparation of Standard Antigen Suspension 178 
Measuring Antigen Suspension and Serum 178 
Controls 178 
