The chapter "Animal Tissue Techniques" by Gretchen L. Humason provides a comprehensive guide to the preparation and fixation of animal tissues for microscopic examination. The text covers the principles and methods used in histological techniques, emphasizing the importance of rapid and effective fixation to prevent post-mortem changes and ensure the integrity of cellular structures. Key topics include: 1. **Fixation**: The selection and use of fixatives such as formalin, picric acid, acetic acid, and osmium tetroxide, each with specific properties and applications. 2. **Fixing Solutions**: Detailed recipes and procedures for various fixing solutions, including routine fixatives for general microanatomy and specialized fixatives for cell inclusions and special techniques. 3. **Washing and Post-Fixation Treatments**: Techniques for washing out excess fixative and performing post-fixation treatments like chromatization, deformalization, and decalcification to improve staining and preservation. 4. **Perfusion**: An advanced method for rapid fixation of tissues, particularly useful for organs like the central nervous system that are difficult to remove from the body quickly. 5. **Special Procedures**: Additional methods and modifications for specific tissues and applications, such as those for glycogen, mitochondria, and calcified areas. The chapter aims to provide a practical guide for both beginners and experienced technicians, ensuring that tissues are prepared correctly for subsequent staining and microscopic examination.The chapter "Animal Tissue Techniques" by Gretchen L. Humason provides a comprehensive guide to the preparation and fixation of animal tissues for microscopic examination. The text covers the principles and methods used in histological techniques, emphasizing the importance of rapid and effective fixation to prevent post-mortem changes and ensure the integrity of cellular structures. Key topics include: 1. **Fixation**: The selection and use of fixatives such as formalin, picric acid, acetic acid, and osmium tetroxide, each with specific properties and applications. 2. **Fixing Solutions**: Detailed recipes and procedures for various fixing solutions, including routine fixatives for general microanatomy and specialized fixatives for cell inclusions and special techniques. 3. **Washing and Post-Fixation Treatments**: Techniques for washing out excess fixative and performing post-fixation treatments like chromatization, deformalization, and decalcification to improve staining and preservation. 4. **Perfusion**: An advanced method for rapid fixation of tissues, particularly useful for organs like the central nervous system that are difficult to remove from the body quickly. 5. **Special Procedures**: Additional methods and modifications for specific tissues and applications, such as those for glycogen, mitochondria, and calcified areas. The chapter aims to provide a practical guide for both beginners and experienced technicians, ensuring that tissues are prepared correctly for subsequent staining and microscopic examination.