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 36 



4. Isolation and Cultivation of Antagonistic Microorganisms j 

 Methods of Measuring Antibiotic Action 53 



5. Bacteria as Antagonists 85 



6. Actinomycetes as Antagonists 108 



7. Fungi as Antagonists 1 30 



8. Microscopic Animal Forms as Antagonists 154 



9. Antagonistic Relationships between Microorganisms, 



Viruses, and Other Nonspecific Pathogenic Forms 1 63 



10. Chemical Nature of Antibiotic Substances 170 



1 1 . The Nature of Antibiotic Action 2 1 8 



12. Utilization of Antibiotic Substances for Disease Control 261 



13. Microbiological Control of Soil-borne Plant Diseases 300 



14. The Outlook for the Future 314 

 Classification of Antibiotic Substances 329 

 Glossary 331 

 Bibliography 233 

 Index of Microorganisms 395 

 General Index ' 403 



62i9i 



