The passage discusses the differences in risk management between farmers and other types of businesses. Farmers face significant risks due to unpredictable market prices and yields, necessitating a large safety margin. Scientific methods have reduced these risks but cannot address price volatility, which is a challenge for policymakers. The author recommends Mr. Hall's book as a useful guide for addressing this issue. The second part reviews three books: 1. **The New Public Health** by Prof. H. W. Hill: This book introduces modern public health concepts, focusing on individual health rather than environmental factors. It emphasizes the importance of identifying infected individuals and controlling their excreta to prevent disease spread. 2. **The Pathology of Tumors** by Dr. E. H. Kettle: This book provides a comprehensive overview of tumor characteristics, occurrence, and pathology, including both benign and malignant tumors. It is well-illustrated but lacks recent advancements in understanding body fluid changes in malignant diseases. 3. **Harper's Hydraulic Tables** by J. H. Harper: This book offers detailed hydraulic solutions for water flow in various conduits, using established formulas. It includes tables and diagrams that are useful for preliminary approximations and can help avoid detailed experimental calculations.The passage discusses the differences in risk management between farmers and other types of businesses. Farmers face significant risks due to unpredictable market prices and yields, necessitating a large safety margin. Scientific methods have reduced these risks but cannot address price volatility, which is a challenge for policymakers. The author recommends Mr. Hall's book as a useful guide for addressing this issue. The second part reviews three books: 1. **The New Public Health** by Prof. H. W. Hill: This book introduces modern public health concepts, focusing on individual health rather than environmental factors. It emphasizes the importance of identifying infected individuals and controlling their excreta to prevent disease spread. 2. **The Pathology of Tumors** by Dr. E. H. Kettle: This book provides a comprehensive overview of tumor characteristics, occurrence, and pathology, including both benign and malignant tumors. It is well-illustrated but lacks recent advancements in understanding body fluid changes in malignant diseases. 3. **Harper's Hydraulic Tables** by J. H. Harper: This book offers detailed hydraulic solutions for water flow in various conduits, using established formulas. It includes tables and diagrams that are useful for preliminary approximations and can help avoid detailed experimental calculations.