TABLE OF CONTENTS 

 Preface 5 



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PART I. THE BACTERIOPHAGE 



Introduction 15 



CHAPTER I. BACTERIOLYSIS 



Bacteriolysis 23 



Technic for the isolation of the bacteriophage 24 



Technic for enhancing virulence 29 



Enumeration of the bacteriophagous ultramicrobes 31 



Multiplication of the ultramicroscopic bacteriophage 34 



The bacteriophage : An obligatory parasite 38 



The effect of the condition of the bacteria 40 



The influence of the medium 42 



Culture of the bacteriophage on solid media: Isolated colonies 45 



Effect of the concentration of bacteria in the medium; inhibitory 



effects of the products of lysis 49 



Effect of external physical conditions 53 



Effect of antiseptics upon lysis 54 



Soluble substances of the bacteria 57 



The ultramicrobial bacteriophage: An endoparasite 58 



Bacteriolysis under the microscope 61 



CHAPTER II. THE BACTERIOPHAGE AND THE BACTERIUM 



Virulence of the bacteriophage 66 



Evaluation of the degree of virulence 69 



Resistance of the bacterium 70 



The origin of secondary cultures 73 



Instability of mixed cultures 76 



The characters of mixed cultures 78 



The resistant bacterium 84 



Microscopic observations 89 



The acquisition of resistance 91 



Production of antilysins by bacteria 92 



Multiple cultures 94 



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