CONTENTS 



XXI 



CHAPTER VIII 



Modifications of the Germ-Plasm caused by Amphi- 

 mixis — 



1. The necessity of a halving of the germ-plasm . 



2. Proof that the essential part in the process of ' reducing 



division ' consists in the extrusion of ids 



PAGE 



235 



240 



CHAPTER IX 



Ontogeny Resulting from the Union of the Germ-Plasm 

 OF TWO Parents — 



1. The nature of the offspring as determined by the process 



of fertilisation ........ 



2. The share taken by the ancestors in composition of the 



germ -plasm ....... 



3. The struggle of the ids in ontogeny . 



a. Plant-hybrids .... 



b. Intercalary remarks on variation . 



c. The struggle of individual characters 



4. The force of heredity .... 



5. Summary of Chapter IX. 



CHAPTER X 



The Phenomena of Reversion in their Relation to 

 Amphimixis — 



1. Reversion to racial characters in plant-hybrids 



2. Reversion to individual characters in man 



3. Reversion to the characters of ancestors far removed in 



animals and plants .... 



4. Reversion to rudimentary characters 



5. Preliminary summary of sections 1-5 



6. Reversion in asexual reproduction . 



a. Reversion in the process of gemmation 

 h. Reversion in parthenogenesis 



7. Proof that the determinants become disintegrated into 



biophors ......... 



CHAPTER XI 



Dimorphism and Polymorphism — 



1. Normal dimorphism ....... 



2. Pathological dimorphism : haemophilia .... 



3. Polymorphism ........ 



4. Dichogeny in plants ....... 



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