CONTENTS 



CHAPTER I 



PAGE 



HEREDITY AND INHERITANCE : DEFINED AND ILLUS- 

 TRATED I 



§ i . Importance of the Study of Heredity. § 2. What the Terms 

 Mean. § 3. Heredity and Inheritance in Relation to other Bio- 

 logical Concepts. § 4. A Question of Words. § 5. The Problems 

 Illustrated. § 6. Denials of Inheritance. 



CHAPTER II 

 THE PHYSICAL BASIS OF INHERITANCE .... 26 



§ 1. What is true in the Great Majority of Cases. § 2. Diverse 

 Modes of Reproduction. § 3. The Hereditary Relation in Uni- 

 cellular Organisms. § 4. The Hereditary Relation in the Asexual 

 Multiplication of Multicellular Organisms. § 5. Nature and 

 Origin of the Germ-cells. § 6. Maturation of the Germ-cells. 

 § 7. Amphimixis and the Dual Nature of Inheritance in Sexual 

 Reproduction. § 8. Inheritance in Parthenogenesis. § 9. Wherein 

 the Physical Basis precisely consists. 



CHAPTER III 



HEREDITY AND VARIATION 66 



§ 1. Persistence and Novelty. § 2. The Tendency to Breed 

 True. § 3. Different Kinds of Organic Change. § 4. Classifica- 

 tion and Illustration of Variations. § 5. Fluctuating Variations. 

 § 6. Discontinuous Variations. § 7. De Vries on Fluctuations and 

 Mutations. § 8. Causes of Variation. 



xi 



