CONTENTS 



Preface page ix 



I INTRODUCTION I 



II CLONAL PHENOMENA IN BACTERIAL AND 



VIRAL POPULATIONS 4 



1 Adaptive enzyme formation and other 

 adaptive changes 4 



2 Mutation 6 



3 Population genetics of bacteria and 



viruses 9 



{a) Periodic selection in bacterial cultures 10 



{b) Pseudo-mutation (Novick and 



Weiner's experiment) 12 



{c) 0-D change in influenza virus A 15 



{d) The process of viral infection 2 1 

 {e) Changes in myxomatosis virulence 



in the field 23 



III THE FACTS OF IMMUNITY 29 



1 The nature of ' antibody ' 30 



2 Differences between primary and 

 secondary response 31 



3 Lack of immunological reactivity to 



body constituents 33 



4 The qualitative types of immune 



response 36 



5 Congenital agammaglobulinaemia 42 



6 Lymphocytes and plasma cells as anti- 

 body producers 44 



7 Summary 46 



