CONTENTS 



CHAPTER 



I. Introduction. 



1. The triangle of life ' . 



2. A definition of heredity 



3. The maintenance of life 



4. Somatoplasm and germplasm 



II. The Carriers of the Heritage. 



1. Introduction 



2. The cell theory . 



3. A typical cell 



4. Mitosis .... 



5. Amitosis .... 



6. Sexual reproduction . 



7. Maturation 



8. Fertilization 



9. Parthenogenesis 



10. The hereditary bridge 



11. The determiners of heredity 



12. The chromosome theory 



13. The enzyme theory of heredity 



14. Conclusion 



III. Variation. 



1. The most invariable thing in nature 



2. The universality of variation 



3. The kinds of variation with respect to 



a. Nature 



h. Duplication 



c. Utility 



d. Direction in evolution 



e. Source 

 /. Normality 

 g. Degree of continuity . 

 h. Character . 

 i. Relation to an average standard 

 j. Heritability . . . . 



their 



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IX 



