CONTENTS 



PAGE 



LECTURE I 



Present Status of the Question . . 



LECTURE II 



Evidences for the Theory — Classification, Domestica- 

 tion and Comparative Anatomy 27 



LECTURE III 



Evidence from Embryology and Blood Tests ... 57 



LECTURE IV 

 Evidence from Palaeontology 82 



LECTURE V 

 Evidence from Geographical Distribution .... 120 



LECTURE VI 



Evidence from Experiment — Conclusion 149 



