CONTENTS XI 



6. Specific aggregation 105 



7. Agglutination of phage-coated bacteria 106 



8. Specific soluble substances 107 



9. Kinetics of neutralization 109 



10. Anomalous neutralization behavior 113 



1 1 . Host dependence of serum-survivor assay 114 



12. Inheritance of antigenic specificity 116 



13. Mechanism of phage neutralization 117 



IX Host Specificity 121 



1. Microbial hosts for phages 121 



2. Host ranges of bacteriophages 122 



3. Host specificity in adsorption 123 



4. Host specificity in infection 124 



5. Acquisition of phage resistance by mutation 125 



6. Acquisition of phage resistance by lysogenization . 128 



7. Phage mutations affecting host range 129 



8. Phenotypic modification of host range 132 



a. Phenotypic mixing 132 



b. Host-controlled variation 133 



9. Summary 135 



X Adsorption of Phage to Host Cell 137 



1. Kinetics of adsorption 138 



2. The ionic environment 141 



3. Organic cofactors 143 



4. The stepwise nature of adsorption 147 



5. Chemical nature of receptor sites 150 



6. Summary 159 



XI Stages in Phage Multiplication 161 



1. Initiation of infection 161 



a. Penetration 161 



b. Release of DNA from the phage particle. . . 163 



c. Puncture of the bacterium 164 



2. The latent period 169 



3. Burst size 170 



4. Premature lysis 172 



5. Phage multiplication studied by irradiation of in- 

 fected bacteria 175 



6. Morphological stages in phage development 182 



7. Conclusion 187 



