14 INBREEDING ,AND OUTBREEDING 



the origm of outbreeding as a social habit, and have con- 

 tributed nothing whatever toward the solution of the ques- 

 tions of inbreeding and outbreeding in the sense in which 

 they will be treated here. It is probable, indeed, that these 

 customs usually originated without regard to matters of 

 physical inheritance. The tribes concerned had seldom 

 risen to a state of culture where the welfare of their de- 

 scendants might be expected to cause anxiety, since in few 

 case^ had there been that development of animal hus- 

 bandry necessary for the first glimpse into the mysteries 

 of heredity. 



These observations do not necessarily apply to the 

 marriage folkways which developed in western Asia and 

 Europe and were passed on to the United States. Our 

 laws preventing marriages between certain degrees of 

 kinship have been moulded by the touch of various civil- 

 izations, but in the main they are a legal heritage from the 

 code of Hammurabi through the Hebraic Tahnud. Since 

 they are based largely upon the customs of pastoral na- 

 tions, it may be they had some foundation in experience, 

 half-truths drawn from casual and fragmentary observa- 

 tions of the shepherd and the cattleman. There is no his- 

 torical record of such rational basis, however. Many of 

 the conventionalisms rigidly stabilized by the hand of re- 

 ligious authority have not the slightest biological justifi- 

 cation. "Witness the English laws preventing marriage 

 with a deceased wife 's sister. On the other hand, if there 

 had not been a dim but real fear of evil consequences aris- 

 ing from inbreeding, there would be something extraordi- 

 nary in the frequencies with which taboos against 

 consanguineous matings have persisted. Among the 

 peoples contributing to European civilization, caste sys- 



