C CONTENTS 



Analysis of Bombardment Results 82 



The Action of X-Rays 86 



Secondary Radiation Effects 88 



Summary of Utility of Radiation Studies 90 



Results of Infectivity Studies 91 



Combined Thermal and lonizing-Radiation Action on a Virus . . 93 



Structural Deductions 96 



Varied Effects of X-Radiation on Bacteriophage 98 



Structural Inferences from Radiation Studies 100 



IV. Theemal Inactivation OF Viruses 103 



Outline of the Theory of Thermal Inactivation 103 



Thermal Inactivation of Viruses 109 



Inactivation as a Function of pH 116 



Pressure Effects on Thermal Inactivation 117 



Conclusions from Thermal-Inactivation Studies 119 



V. The Surface of Viruses 122 



Surface Functions of Viruses 123 



Adsorption 124 



Polypeptide Attachment 130 



Virus Serology 132 



Neutralization of Infectivity 134 



Surface Inactivation by Antibody 134 



Serological Inactivation of Viruses 135 



Thermal Inactivation of Serological Affinity 140 



Hemagglutination 142 



Nature of the Virus Surface 144 



VI. Action of Ultraviolet Light on Viruses 146 



Molecular Absorption of Ultraviolet Light 146 



Absorption by Some Definite Molecules 149 



The Absorption Spectrum of Tobacco Mosaic Virus 152 



Absorption Spectra of Other Viruses 156 



Action Spectra 156 



Infectivity and Hemagglutination Action Spectra of Influenza Virus 160 



Action Spectra for Different Viruses 162 



Quantum Yield 162 



Multiplicity Reactivation after Ultraviolet Treatment 164 



Photoreactivation of Bacteriophage 165 



Summary and Conclusions from Action Spectra 166 



VII. Sonic and Osmotic Effects on Viruses 169 



Pressures Developed 169 



Cavitation 170 



Sonic Irradiation Procedures 170 



Sonic Effects on Viruses 171 



Osmotic Effects on Viruses 177 



