CONTENTS 



Xlll 



CHAPTER 



5. Potency . 



a. Total potency 



b. Partial potency 



c. Failure of potency 



6. Blending inheritance 



7. The case of rabbit ears 



8. The Nilsson-Ehle discovery 



9. The application of Nilsson-Ehle's explanation to the 



case of rabbit ear-length 

 10. Human skin color . 



X. The Determination of Sex. 



1. Speculations, ancient and modern 



2. The nutrition theory 



3. The statistical study of sex 



4. Monochorial twins . 



5. Selectiv^e fertilization 



6. The neo-Mendelian theory of sex 



a. Microscopical evidence 



1. The "x" chromosome 



2. Various forms of x chromosomes 



3. Sex chromosomes in parthenogenesis 



b. Castration and regeneration experiments 



c. Sex-limited inheritance 



1. Color-blindness 



2. The English currant-moth 



d. Behavior of hermaphrodites in heredity 



7. Conclusion 



XI. The Application to Man. 



1. 

 2. 

 3. 



PAGE 



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193 

 196 



197 

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 207 

 207 

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 213 

 214 

 216 

 220 

 222 



5. 

 6. 



The application of genetics to man .... 224 



Modifying factors in the case of man . . . 225 



Experiments in human heredity .... 227 



a. The Jukes 227 



6. The descendants of Jonathan Edwards . . 228 



c. The Kallikak family 229 



Moral and mental characters behave like physical 



ones 230 



The character of human traits ..... 231 



Hereditarv defects . . . . . . . 232 



