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.
[Footnote 1: Cf. Bell, "A Few Thoughts Concerning Eugenics." In
_National Geographic Magazine_, March, 1908.]
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
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
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, their effects upon society, and more
particularly their bearing upon American social evolution. The
problems to be considered are not only those which relate primarily to
the individual and secondarily to the race, such as the supposed
effect of blood relationship in the parents upon the health and
condition of the offspring; but also the effect, if any, which such
marriages have upon the birth-rate, upon the proportion of the sexes
at birth, and the most fundamental problem of all, the relative
frequency with which consanguineous marriages take place in a given
community.
No thorough and systematic study of the subject has ever been made,
and could not be made except through the agency of the census. The
statistical material here brought together is fragmentary and not
entirely satisfactory, but it is sufficient upon which to base some
generalizations of scientific value. The sources of these data are
largely American. Little attempt is made to study European material,
or to discuss phases of the problem which are only of local concern.
Some topics, therefore, which have frequently been treated in
connection with the general subject of consanguineous marriages are
here ignored as having no scientific interest, as for instance that of
the so-called "marriages of affinity," which has been so warmly
debated for the past fifty years in the British Parliament.
For obvious reasons it will often be impossible to distinguish between
the different degrees of consanguinity, but wherever possible the
degree will be specified. It is probable that where a number of
marriages are vaguely given as consanguineous, few are more distant
than second cousins, for in the United States especially, distant
relationships are rarely traced except by genealogists. In designating
degrees of relationship the common terminology will be used, as in the
following table, expressing, however, the rather clumsy expression,
"first cousin once removed" by the simpler form "1-1/2 cousin."
[Illustration]
By far the greater part of the literature of consanguineous marriage
is of a controversial rather than of a scientific nature, and a search
for statistical evidence for either side of the discussion reveals
surprisingly little that is worthy of the name. Yet men of high
scientific standing have repeatedly made most dogmatic assertions in
regard to the results of such unions, and have apparently assumed that
no proof was necessary. For example, Sir Henry Sumner Maine "cannot
see why the men who discovered the use of fire, and selected the wild
forms of certain animals for domestication and of vegetables for
cultivation, should not find out that children of unsound constitution
were born of nearly related parents."[2]
[Footnote 2: Maine, _Early Law and Custom_, p. 228.]
Much space is given to the alleged "innate horror of incest," and
frequent appeals are made to Scripture, wrongly assuming that the
marriage of cousins is prohibited in the Mosaic Law.
The origin of "prohibited degrees" is only conjectural. The Christian
Church apparently borrowed its prohibitory canons from the Roman
Law,[3] and a dispensation is still necessary before a Catholic can
marry his first cousin. However, such dispensations have always been
easy to obtain, especially by royal families, and even the marriage of
uncle and niece sometimes occurs, as among the Spanish Habsburgs, and
as recently as 1889 in the House of Savoy.
[Footnote 3: Luckock, _History of Marriage_, p. 282.]
The prohibition of the marriage of first cousins was removed in
England by the Marriage Act of 1540,[4] but by this time the idea of
the harmfulness of kinship marriage was so thoroughly impressed upon
the people that they were very prone to look askance at such unions,
and if they were followed by any defective progeny, the fact would be
noted, and looked upon as a chastisement visited upon the parents for
their sin. Naturally the idea became proverbial, and in some places it
has influenced the civil law.
[Footnote 4: Child, "On Marriages of Consanguinity," in
_Medico-Chirurgical Review_, April, 1862, p. 469.]
Perhaps the first printed discussion of the subject in America is from
the pen of Noah Webster, in an essay which should be as interesting to
the spelling reformer as to the sociologist.[5] He writes: "It iz no
crime for brothers and sisters to intermarry, except the fatal
consequences to society; for were it generally practised, men would
become a race of pigmies. It iz no crime for brothers' and sisters'
children to intermarry, and this iz often practised; but such near
blood connections often produce imperfect children. The common peeple
hav hence drawn an argument to proov such connections criminal;
considering weakness, sickness and deformity in the offspring az
judgements upon the parents. Superstition iz often awake when reezon
iz asleep."
[Footnote 5: Webster, _Collection of Essays and Fugitiv Writings on
Moral, Historical, Political and Religious Subjects_, 1790, p. 322.]
From about 1855 to 1880 much was written about the effect of
consanguineal interbreeding. One of the first contributions came from
America. In 1858 Dr. S.M. Bemiss, of Louisville, Kentucky, reported to
the American Medical Association the results of his investigation of
833 cases of consanguineous marriage.[6] His compilation remains to
this day the largest single piece of direct statistical work on the
subject. Unfortunately, however, his statistics have a strong, if
unintentional, bias which seriously affects their value. In France one
of the earliest discussions was by M. Boudin,[7] who evidently
obtained the Bemiss report (attributing it to Dr. O.W. Morris, who had
quoted freely from Bemiss),[8] and enlarged greatly upon its
fallacies. He also collected statistics of the deaf-mutes in Paris,
and, by an amazing manipulation of figures, "demonstrated" that
consanguinity of the parents was the cause of nearly one-third of the
cases of congenital deafness. The savants of the Société
d'Anthropologie took sides and the debate became very entertaining.
Finally M. Dally came to the rescue, and published some very sane and
logical articles which avoided both extremes, and first advanced the
theory that any ill effects of consanguineous marriage should be
attributed to the intensification of inherited characteristics.[9]
[Footnote 6: See _Transactions of the American Medical Association_,
1858, pp. 321-425.]
[Footnote 7: "Du Croisement des families," _Mem. de la Société
d'Anthropologie_, vol. i, 1860-63, pp. 505-557.]
[Footnote 8: See Morris: "On Marriages of Consanguinity," in _Amer.
Med. Times_, Mar. 23, 1861.]
[Footnote 9: See _Bulletins de la Société d'Anthropologie_, 1863, pp.
515-575; 1877, pp. 203-213.]
In England similar discussions took place during the same period,
complicated, however, by the presence of the patient and
long-suffering "deceased wife's sister." The best of the English work
has been the statistical study by George H. Darwin,[10] and the
classic "Marriage of Near Kin" by Alfred H. Huth, a book of 475 pages,
including a very complete bibliography to the date of the second
edition, 1885. Although Mr. Huth's book is not free from error, and is
encumbered with a large amount of worthless material, it is now after
thirty-three years, by far the best treatment of the subject.
[Footnote 10: "Marriages of First Cousins in England and their
Effects," _Journal Statistical Society_, 1875, pp. 153-184.]
In Italy Dr. Montegazza,[11] in Spain Señor Pastor[12] and others,
have made useful contributions. German writers have usually preferred
more general subjects, but many of them have given much space to
consanguineous marriage in sociological and biological works.
[Footnote 11: _Studj Sui Matrimonj Consanguinei_. Quoted by Darwin,
op. cit., p. 178.]
[Footnote 12: "De los Matrimonios entre Parientes," Memorias _de la
Real Academia de Ciencias Morales y Políticas_, vol. ii, pp. 369-400.]
Since the appearance of the Bemiss report little has been published in
this country which bears directly upon our subject. The most important
American contribution, however, is to be found in the Special Report
on the Blind and the Deaf, in the Twelfth Census of the United States,
prepared by Dr. Alexander Graham Bell. Although American writers have
had little part in the theoretical discussions, our legislators have
been active, so that the statutes of every state specify degrees of
kinship within which marriage is prohibited. In at least sixteen
states the prohibition is extended to include first cousins. In New
Hampshire such marriages are void and the children are illegitimate.
Other states in which first-cousin marriage is forbidden are
Pennsylvania, Ohio, Indiana, Illinois, Michigan, Kansas, North Dakota,
South Dakota, Wyoming, Nevada, Washington, Oregon, Missouri, Arkansas,
and Louisiana. Since both Oklahoma and Indian Territory had similar
laws, the present State of Oklahoma should probably be added to this
list. In all of these states marriages within the prohibited degrees
are incestuous or void or both, except in Ohio, where no express
declaration is made in the statute. In Ohio, Indiana, Nevada and
Washington the law is made to read: "and not nearer of kin than
_second cousins_," therefore including "1-1/2 cousins" within the
prohibited degrees. In many states the marriage of step relatives is
forbidden, as also marriage with a mother-in-law or father-in-law. Of
the territories, Arizona, Alaska, and Porto Rico forbid the marriage
of first cousins, but in Porto Rico the court may waive the
impediment.
These laws probably have some effect in reducing the number of
consanguineous marriages in these states, but the sentiment back of
the law is more responsible for the decrease in the number of such
unions than the law itself. For in the nature of things enforcement
would be very difficult, and apparently little real effort is made in
that direction. In Ohio, and probably elsewhere, the question as to
consanguinity is not directly put to the applicants for a marriage
license. The applicants are required to answer the usual questions in
regard to age, parentage, residence, etc., and are then required to
swear that their previous statements have been correct and that
neither of them is "epileptic, imbecile or insane," that they are "not
nearer of kin than second cousins, and not at the time under the
influence of any intoxicating liquor or narcotic drug." Undoubtedly
violations of the consanguinity clause are very frequent, and it is
likewise easily evaded by going to another state where the laws are
more liberal. One effect of the law is to provide a painless method of
severing the marriage bond. A correspondent, who is a District Court
Judge in Kansas, in reporting a case of first cousin marriage, adds
that he "divorced them on the ground of consanguinity."
In the absence of direct investigation by the Census Bureau, or other
public records of consanguineous marriages, perhaps the most promising
field for research is in the genealogical records of American
families. Several thousand volumes of such material have been
published within the last half-century, and a large number of these
are very carefully and scientifically prepared. The material gathered
from such sources is very accurate in regard to the number of births,
youthful deathrate etc., but mental or physical defects are rarely
mentioned. The greatest objection to the utilization of this material,
however, is the amount of labor necessary in order to glean the
desired facts from the mass of irrelevant data. For example, in order
to find one case of first cousin marriage it is necessary on an
average, to examine the records of nearly two hundred other marriages.
The collection of data from personal sources is likewise open to grave
objections. Not only is the informant likely to be biassed, but the
cases which he will remember will be those in which something unusual
has occurred. Herein lay the fallacy in the conclusions of Dr. Bemiss.
I have endeavored to overcome this bias by restricting my requests
for information to genealogists and others who would more naturally
appeal to records, but my efforts have been only partially successful.
The number of cases of consanguineous marriage, embracing all degrees
of consanguinity, which I have collected from these two sources,
genealogies and correspondence, is 723, a number too small in itself
to establish any definite conclusions; but by using this material in
connection with other related data, I trust I may be able to add
something to the comparatively small amount of real knowledge which
the world already possesses in regard to the marriage of kin.
In the course of my investigations I visited Smith's Island, in the
Chesapeake Bay, about twelve miles across Tangier Sound, from
Crisfield, Maryland, and nearly opposite the mouth of the Potomac.
Here is a community of about seven hundred people, who are principally
engaged in the sea-food industry. Their ancestors have lived on the
island for many generations and there have been comparatively few
accessions to the population from the mainland. As a natural
consequence the population is largely a genetic aggregation.
Consanguineous marriages have been very frequent, until now nearly all
are more or less interrelated. Out of a hundred or more families of
which I obtained some record, at least five marriages were between
first cousins. All of these were fertile, and all the children were
living and apparently healthy. Since over thirty per cent of the
inhabitants bear one surname (Evans), and those bearing the first four
surnames in point of frequency (Evans, Brad-shaw, Marsh, and Tyler)
comprise about fifty-nine per cent of the population, it will readily
be seen that comparatively few absolutely non-related marriages take
place. Yet in this community from September, 1904, to October, 1907,
or during the residence there of the present physician, Dr. P.H.
Tawes, there have been 87 births and but 30 deaths, the latter from
the usual causes. During this period there has not been a single case
of idiocy, insanity, epilepsy, deaf-mutism or even of typhoid fever on
the island.
The evidence gathered from various other isolated communities is very
conflicting. Huth describes a great many of them which have existed
for many generations without crosses without ill results. Other
writers quote instances where whole communities have become
degenerate. Until the antecedents of a community are known it is of
course impossible to estimate the effect of consanguinity. The
exceptionally high percentage of deaf-mutism on Martha's Vineyard may
to some extent be due to a high percentage of consanguineous marriage,
but that inbreeding is not the primary cause is revealed by the
records showing that among the first settlers were two deaf-mutes,
whose defect has been inherited from generation to generation for two
hundred and fifty years.[13]
[Footnote 13: See article in Cincinnati _Gazette_, Jan. 22, 1895.]