CHAPTER V

CONSANGUINITY AND MENTAL DEFECT

Idiocy and Insanity--Inheritability of Mental Defect--Intensified
Heredity--Barr's Investigations--Other American and English
Data--Mayet's Prussian Statistics--Genealogical Data


CHAPTER VI

CONSANGUINITY AND THE SPECIAL SENSES

United States Census Data--The Blind--Consanguinity of Parents--Blind
Relatives--Degree of Blindness--Causes of Blindness--Retinitis
Pigmentosa--European Data--Probability of Blind Offspring of
Consanguineous Marriages--The Deaf--Irish Census--Scotland and
Norway--United States Census--Consanguinity of Parents--Deaf
Relatives--Causes of Deafness--Degree of Deafness--Direct Inheritance
of Deafness--Intensification through Consanguinity--Dr. Fay's
Statistics--Personal Data--Probability of Deaf Offspring from
Consanguineous Marriages--Opinion of Dr. Bell


CHAPTER VII

SUMMARY AND CONCLUSION