CONTENTS 



PAGE 



INTRODUCTION. GENETICS, A NEW SCIENCE ... 1 



CHAPTER 



I. THE DUALITY OF INHERITANCE 6 



II. GERM-PLASM AND BODY, THEIR MUTUAL 



INDEPENDENCE 27 



III. MENDEL'S LAW OF HEREDITY 33 



IV. THE DETERMINATION OF DOMINANCE; 



HETEROZYGOUS CHARACTERS AND THEIR 

 FIXATION; ATAVISM OR REVISION. ... 52 



V. EVOLUTION OF NEW RACES BY Loss OR 



GAIN OF CHARACTERS 72 



VI. EVOLUTION OF NEW RACES BY VARIATIONS 



IN THE POTENCY OF CHARACTERS .... 87 



VII. CAN MENDELIAN UNIT-CHARACTERS BE 



MODIFIED BY SELECTION? 106 



VIII. MENDELIAN INHERITANCE WITHOUT DOMI- 

 NANCE, " BLENDING" INHERITANCE . . . 128 



IX. THE EFFECTS OF INBREEDING 143 



X. HEREDITY AND SEX 153 



INDEX 183 



