CONTENTS 



1 . Soils and Water Basins as Habitats of Microorganisms i 



2. Human and Animal Wastes 19 



3. Interrelationships among Microorganisms in Mixed Popula- 

 tions 38 



4. Isolation and Cultivation of Antagonistic Microorganisms} 

 Methods of Measuring Antibiotic Action 55 



5. Bacteria as Antagonists 80 



6. Actinomycetes as Antagonists 102 



7. Fungi as Antagonists 124 



8. Microscopic Animal Forms as Antagonists 143 



9. Antagonistic Relationships between Microorganisms, Vi- 

 ruses, and Other Nonspecific Pathogenic Forms 152 



10. Chemical Nature of Antibiotic Substances 156 



11. The Nature of Antibiotic Action 189 



12. Utilization of Antagonistic Microorganisms and Antibiotic 

 Substances for Disease Control 221 



13. Microbiological Control of Soil-borne Plant Diseases 246 



14. The Outlook for the Future 259 

 Classification of Antibiotic Substances 270 

 Glossary 271 

 Bibliography 273 

 Index of Microorganisms 331 

 General Index 339 



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