CONSANGUINEOUS MARRIAGES
IN THE
AMERICAN POPULATION

STUDIES IN HISTORY, ECONOMICS AND PUBLIC LAW

EDITED BY THE FACULTY OF POLITICAL SCIENCE OF COLUMBIA UNIVERSITY

[Volume XXXI] [Number 3]

CONSANGUINEOUS MARRIAGES
IN THE
AMERICAN POPULATION

BY

GEORGE B. LOUIS ARNER, Ph.D.

University Fellow in Sociology

1908

PREFACE

This monograph does not claim to treat exhaustively, nor to offer a final solution of all the problems which have been connected with the marriage of kin. The time has not yet come for a final work on the subject, for the systematic collection of the necessary statistics, which can only be done by governmental authority, has never been attempted. The statistics which have been gathered, and which are presented in the following pages, are fragmentary, and usually bear upon single phases of the subject, but taken together they enable us better to understand many points which have long been in dispute.

The need for statistics of the frequency of occurrence of consanguineous marriages has been strongly felt by many far-sighted men. G.H. Darwin and A.H. Huth have tried unsuccessfully to have the subject investigated by the British Census, and Dr. A.G. Bell has recently urged that the United States Census make such an investigation.^[1] Another motive for undertaking this present work, aside from the desire to study the problems already referred to, has been to test the widely prevalent theory that consanguinity is a factor in the determination of sex, the sole basis of which seems to be the Prussian birth statistics of Düsing, which are open to other interpretations.

The stock illustrations from isolated communities have been omitted as too difficult to verify, and little space has been given to the results of the inbreeding of domestic animals, for although such results are of great value to Biology, they are not necessarily applicable to the human race.

The writer regrets that it is impossible here to acknowledge all his obligations to those who have assisted him in the preparation of this work. Such acknowledgement is due to the many genealogists and other friends who have kindly furnished detailed cases of consanguineous marriage. For more general data the writer is especially indebted to Dr. Alexander Graham Bell, to Dr. Martin W. Barr, to Professor William H. Brewer of Yale University, and to Dr. Lee W. Dean of the University of Iowa. In the preparation of the manuscript the suggestions and criticisms of Professors Franklin H. Giddings and Henry L. Moore have been invaluable.

G.B.L.A.

MARCH, 1908.

CONTENTS

PREFACE

CONTENTS

CHAPTER I

INTRODUCTION

Problems to be Treated—Degrees of Consanguinity—Literature of the Subject—Noah Webster—Bemiss—Dally—G.H. Darwin—Huth—Bell—Legal Status in the United States—Methods of Investigation—Genealogical—Personal—Isolated Communities

CHAPTER II

RATIO OF THE CONSANGUINEOUS TO ALL MARRIAGES

Previous Estimates—Mayo-Smith—Mulhall—Darwin—Application of Darwin's Method to American Data—Direct Method—Consanguineal Attraction—Same-name and Different-name Cousin Marriages—Summary

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

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

Summary of Results—Inbreeding and Evolution—Effects of Close Inbreeding—Crossing and Variation—"Difference of Potential"—Resemblance and Intensification—Coefficient of Correlation between Husband and Wife—Between Cousins—Between Brothers and Sisters—Consanguinity and Eugenics—Consanguinity and Social Evolution—Conclusion

BIBLIOGRAPHY.

GENEALOGIES CONSULTED.

FOOTNOTES

CHAPTER I

INTRODUCTION

The purpose of this essay is to present in a concise form and without bias or prejudice, the most important facts in regard to consanguineous marriages,