INBREEDING AND 

 OUTBREEDING 



CHAPTER I 

 INTEODUCTION 



INTEREST in the effects of inbreeding and of outbreed- 

 ing is not confined to the professional biologist. Histori- 

 cally these are old, old problems, practical problems of 

 considerable significance bound up with man's gravest 

 affairs, his marriage customs and his means of subsist- 

 ence. In these matters, moreover, the passing of time 

 has not diminished the value to be attached to their solu- 

 tion. The questions involved belong to theoretical biol- 

 ogy, it is true, and the professional biologist may lay claim 

 to the first satisfactory analyses ; but relatively his inter- 

 est is that of yesterday, stimulated by the work of Darwin 

 in establishing the doctrine of Evolution. 



The intimate relation which the effects of various sys- 

 tems of mating bear to these three subjects will be seen 

 more clearly from the following brief explanation. 



Anthropological investigations have shown that many 

 primitive peoples established rigid customs of exogamy 

 marriage outside the family or the clan. Such practices, 

 after their identification with totemic systems by Mac- 

 Lennan, became the subject of much notable speculation. 

 In particular may be mentioned the works of Frazer, Lang 

 and Freud. Yet these writers have thrown little light on 



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