xii CONTENTS 



CHAPTER IV 

 BIOMETRY 



PAGE 



Biology and statistics Normal variations Definite 

 differences Biometrical methods The normal 

 curve Probable error The biometrical treatment 

 of heredity Correlation Structural and mental 

 characters The law of ancestral heredity The 

 effect of selection Johannsen's theory of the pure 

 line Selection in pure lines and in populations - 73 



CHAPTER V 

 THE THEORY OF MUTATION 



Objections to the theories of Lamarck and of Darwin 

 Aristotle and Dr. Thomas Brown on mutation 

 Galton and organic stability Bateson and discon- 

 tinuous variation Symmetry Merism Similar and 

 simultaneous variation Homoeosis The views of 

 de Vries The effect of selection Mutation 

 in (Enothera Eversporting varieties Different 

 methods of mutation The survival of useless struc- 

 tures - 113 



CHAPTER VI 

 THE OLDER HYBRIDISTS 



Kolreuter Knight Herbert Gaertner Naudin 



Millardet - - 148 



CHAPTER VII 

 MENDELISM 



The double nature of animals and of the higher plants 

 Unit characters The inheritance of definite char- 

 acters in cross-bred maize Mono-hybrids and di- 

 hybrids Mendel's law Gregor Johann Mendel 

 Experiments with peas Dominance Heterozygote 

 forms The case of the Andalusian fowl The nature 

 of allelomorphs - 163 



