CONTENTS 



CHAPTER I 



PAGE 



The Problem .... . . i 



CHAPTER n 



Historical ... .... 7 



CHAPTER in 



Mendel's Work 15 



CHAPTER IV 



The Presence and Absence Theory . . 26 



CHAPTER V 



Interaction of Factors 39 



CHAPTER VI 

 Reversion 54 



CHAPTER VII 



Dominance 63 



xi 



