xiv CONTENTS 



CHAPTER 



Regulation 



Heteromorphosis 



Theories of Morphogenesis . . . 



Preformation ...... 



Epigenesis , 



" Weismannism " . . . . 



Vitalism and Mechanism . 

 Summary . . . . . . . 



VII. VARIATION AND HEREDITY . 



Variation . . . . . -v? 

 The Law of Frequency of Error . . 

 Types of Variation Curves . 



Asymmetrical Variation 



Discontinuous Variation 

 Mutations . . 

 Correlated Variability . 

 Effect of Life Conditions on Variation . 

 Causes of Variation . 



Heredity . 



Heredity and Inheritance . 

 Individual Heredity and Racial Heredity 

 Galton's Law of Ancestral Inheritance 



Filial Regression 



Effect of Selection in Heredity 



Pure Lines ...... 



Unit Characters and Mendelian Inheritance 



Sex-limited Inheritance 

 Economic Aspects of the Subject 



The Inheritance of Disease . 



The Inheritance of Defects . 



Eugenics ...... 



VIII. ORGANIC RESPONSE 



Environment ....... 



The Usual Conditions of Environment 



Temperature ...... 



Light 



Chemical Environment 



