CONTENTS 



CHAPTER I 



PAGE 



HEREDITY AND INHERITANCE I 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-^4 Question of Words. 5. The Problems 

 Illustrated. 6. Denials of Inheritance. 



CHAPTER II 

 THE PHYSICAL BASIS OF INHERITANCE . . .. . 26 



i. 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 



I. 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. 



