TABLE OF CONTENTS 
CuapTreR XXVI. HEREDITY IN Pure Lines. Z.H.N. 
Are Determiners (Genes) Constant or Variable? . 
CHAPTER XXVIII. MENDEL’s Laws oF HEREDITY 
Mendel’s Life and Character. J. Arthur Thomson 
Mendel’s Discoveries. J. Arthur Thomson i 
Mendel’s Explanations. J. M. Coulter and M. C. Coilier 2 
Illustrations of Simple Mendelian Inheritance in Both Animals and 
Plants. J. Arthur Thomson . 
CHAPTER XXVIII. THe Puysicat Basis oF MENDELISM. Ernest 
B. Babcock and Roy E. Clausen . 
CHAPTER XXTX. NEO-MENDELISM IN Piants. John M. Coulter 
and Merle C. Coulter F 
Presence and Absence Hypothesis . 
Blends . A 
The Factor Hiypatliesis : 
CHAPTER XXX. NEO-MENDELIAN HEREDITY IN Animals. H.H.N. 
Illustrations of the Factor Hypothesis . 
The Factorial Analysis of Color in Mice 
Different Kinds of Albinos P 
Castle’s Guinea Pigs #8 8 
CHAPTER XXXJ. SEX-LINKED AND OTHER Kinds oF LINKED 
INHERITANCE IN Drosophila AND OTHER SPEcIES. William E. 
Castle . . 
Drosophila Type and Poultry Type ot Sexlinked Thineritanee 
CHAPTER XXXII. LINKAGE AND CROSSING-OVER. William E. 
Castle. 
CHAPTER XXXIII. Sex DeterminaTION. H.H.N.. 
Various Theories of Sex Determination 
The Chromosomal Mechanism of Sex Déterminatiin, 
Sex Determination in Parthenogenetic Species . 
The Poultry Type of Sex Determination 
Sex Differentiation ae ae 
PART V. EUGENICS 
CHAPTER XXXIV. THe INHERITANCE OF HUMAN fone 
PuHysIcaL AND MENTAL. Elliot R. Downing 
CHAPTER XXXV. HuMAN ConseRVATION. Herbert E. Walter : 
How Mankind May Be Improved . 
More Facts Needed . ; : 
Further Application of What We Know Necessary F 
The Restriction of Undesirable Germplasm 
Control of Immigration 
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