[CHAPTER III]

MASCULINITY

Constancy of the Sex-ratio—Consanguinity and Masculinity—Theory of Westermarck and Thomas—Duesing—Gache—Negroes in the United States—Genealogical Material—Other Compilations—Summary

[CHAPTER IV]

CONSANGUINITY AND REPRODUCTION

Theories of the Effect of Consanguinity upon Offspring—Comparative Fertility—Statistics from Darwin and Bemiss—Genealogical Statistics—Youthful Death-rate—Degeneracy—Fallacies in the Work of Bemiss—Isolated Communities—The Jukes—Other Degenerate Families—Scrofula

[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