CHAPTER XI 
CONSANGUINEOUS MARRIAGES AND 
MISCEGENATION 
“We are coming honestly to believe that the world is richer for the 
existence both of other civilizations and of other racial types than our 
own. ... Even if we look at the future of the species as a matter of 
pure biology, we are warned by men of science that it is not safe to 
depend only on one family or one variety for the whole breeding-stock 
of the world. For the moment we shrink from the interbreeding of 
races, but we do so in spite of some conspicuous examples of successful 
interbreeding in the past, and largely because of our complete ig- 
norance of the conditions on which success depends.” —Graham Wal- 
las, Human Nature and Politics, pp. 293, 294. 
THE peoples of the earth have followed thé most varied customs 
in regard to marriage. From extreme inbreeding we have all 
gradations to the crossing of distinct races. Among savage and 
barbarous peoples the practice of exogamy, or marriage outside 
the tribe, is very prevalent. In general, we find that marriages 
between near relatives are forbidden, and often the prohibition 
goes farther and includes those bearing the same name or belong- 
ing to a group which may be specified in various other ways. 
Such prohibitions are not due to any instinctive repugnance tc 
incest,—certainly no such instinct occurs in the lower animals,— 
nor is it reasonable to suppose, as has sometimes been done, that 
they arose from the observed ill effects of consanguineous unions. 
The effect of marriages among near kin is a matter about which 
qualified students of genetics have come to different opinions, and 
it is hardly probable that primitive peoples have been able to 
arrive at valid conclusions on a subject that requires for its 
solution a refinement of inductive method which is quite alien to 
the thinking of untrained men. 
Among plants and animals the effects of inbreeding and cross 
breeding have long attracted the attention of breeders. The 
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