CONTENTS 



INTRODUCTION 5 



CHAPTER I. 



Ontogeny, as a Recapitulation of Phylogeny suggests the Idea 

 of a continuous Action exerted by the Germ Substance 

 upon the Soma throughout the whole of Development.... II 



CHAPTER II. 



1. Phenomena which indicate a continuous formative Action 



which is exerted by Parts of the Soma upon the other 

 Parts throughout the Whole of Development 19 



2. Hypothesis of the Nature of the formative Stimulus 29 



CHAPTER III. 



1. Phenomena which point to the Existence of a central Zone 



of Development . . 53 



2. Hypothesis of the Structure of the germinal Substance 76 



CHAPTER IV. 



1. Phenomena which refute simple Epigenesis 104 



2. Phenomena which refute Preformation 121 



3. Inadmissibility of a homogeneous germ Substance 144 



4. Inadmissibility of preformistic Germs 150 



CHAPTER V. 

 The Question of the Inheritance of acquired Characters 159 



CHAPTER VI. 



The most important of the existing biogenetic Theories in Rela- 

 tion to the Inheritance of acquired Characters 224 



CHAPTER VII. 



The centroepigenetic Hypothesis and the Explanation of In- 

 heritance afforded by it 289 



CHAPTER VIII. 



The Phenomenon of Memory and the vital Phenomenon 316 



Conclusion 356 



Appendix 359 



Index ,401 



