kin, we have only to discuss the bearing of the conclusions thus formed upon the social aggregate, and

environments; that such marriages are more frequent in isolated and in rural communities than in cities; and that with th

umber of children or upon their masculinity, and has little, if any,

stics or peculiarities by double inheritance. The degree of intensification probably varies with the nature of the characte

o the higher evolution of the race: "A settled abode, natural protection from race mixture and the development of a closely inbred social class are the basic conditions of every culture period." But inbreeding must not be carried too far: "In the

constitutionally, and free from disease. After a certain number of generations however, degeneration apparently sets in. The number of generations through which inbreeding may be carried varies with the species, and the purpose for which the animals are bred. Where they are bred primarily for their flesh, a

he lower animals. Instances are well known, however, where incestuous unions have been productive of healthy offspring, and successive generations of offspring of incestuous connection are not unknown; but, although statistics are lacking, it seems to be very often true that children of such unions are degenerate. It may be that the reason for this is that with the laws and social sentiments now prevailing in all civilized communities, only degenerates ever contract inc

h-rate, the higher percentage of idiocy, deafness and blindness, and probably also the scrofulous and other degenerate te

on with no natural variations in any direction, a stagnation which in itself would indicate a comparatively low vitality. Variation and consequent selection is neces

emain for their whole lives, and their descendants after them, in the same spot, surrounded by precisely the same conditions, and intermarry with others doing the same, and who continue this for a series of generations, deteriorate mentally at least, and probably also physically, although there may not be any mixing of blood. Their whole lives, physical, mental, and moral, become fixed and monotonous, and the partners chosen for continuing the race have nothing new to add

ready given. All the phenomena of intensification are simply due to a resemblance between husband and wife in particular characteristics, such as a common tendency toward deafness or toward mental weakness. This resemblance, which may or may not be the result of a common descent, renders more probable the appear

ral, rather than in particular traits or characteristics. In such a case the absence of the stimulating effec

nguinity. A case in point is furnished me by a correspondent. A first cousin marriage which turned out exceedingly well was between strongly contrasted individuals; the husband was "short, stocky and dark complexioned"

marriages from Mr. Francis Galton's Family Records, Professor Pearson found the correlation between husband and wife to be .0931 ± .0467, while weighted by their fertility the correlation was .1783 ± .0210, practically doub

989 ± .0204; and of forearm .1977 ± .0205; with cross coefficients varying from .1403 to .2023. If, as he believes, "The parents of adult children are on the average mor

d be more alike than first cousins in general. A certain degree of resemblance is undoubtedly necessary to complete fertility: husband and wife must be physically compatible, and must b

ith fertility, heterogamy seems to increase fertility. The highest average fertility (4.57) is in those cases where the

for eye color (.265), or between grandparent and grandchild for the same characteristic (.3164).[104] Positive results were also found, with one doubtful exception, for the occurrence of insanity and tuberculosis in cousins. The writer concludes: "The grandparent, the uncle and aunt, and the cousin are on practically the

uring the same characteristics, the fraternal correlation was found to be .508.[106] From measurements of a greater variety of characteristics in school children the mean fraternal correlation was .539.[107] In athletic power the coefficient was still higher, .72 between brothers, .75 between sisters

age of cousins, it is perhaps just as well that existing laws on the subject should remain in force. From the standpoint of eugenics however, it is much more important that the marriage of persons affected with hereditary disease should be prevented. Dr. Bell has pointed out the danger of producing a deaf-mute race by the intermarriage of congenitally deaf persons,[109] and this warning should be mad

hatever may have been the origin of exogamy, the survival of the exogamous type in progressive societies may easily be explained on the ground of superior adaptability, vari

of selection of the strongest and ablest, but after it becomes a caste, the individuals are selected on account of hereditary social position and not primarily on account of ability. Now biological experiments show that although artificial selection may be carried to a point where animals will breed true to a characteristic to within 90 per cent, ye

elements into a homogeneous whole, and the development of a race more versatile and adaptable than any the world has yet known. The general tendency will undoubtedly be toward amalgamation, but there are decided tendencies in the other direction, as for instance in the "first families of Virginia," and in that large element of the New England population which prides itself upon its exclusively Puritan ancestry, and which has inherited from its progenitors that intolerance which characterized the early settlers of New England more than the pioneers of the other colonies. The dynamic fo

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American Medical Associa

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em. de la Société d'Anthropolog

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of Consanguinity," in Amer

9

d'Anthropologie, 1863, pp.

1

and and their Effects," Journal Sta

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sanguinei. Quoted by Da

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morias de la Real Academia de Ciencias M

1

incinnati Gazett

1

and Sociolo

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ty upon the Organs of

1

of Statisti

1

en Norvège. Quo

1

verwandschaft der Elte

1

onary of Stati

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op. cit

2

., p

2

., p

2

et sur les Races Pures." in Bulletins de

2

and their Effects," in Journal of the Stat

2

e Licenses were issued by the Sec

2

upra,

2

e, infr

2

Societ

2

Human Marri

3

der Haarfarben bei den Pferden

3

Geschlechtsverhael

3

ten in Preussen, pp. 24-25; in Staat

3

Statistics, op

3

Natality and Fecu

3

it.,

3

tal Statistics, Pt. 1. Per cent

3

op. cit

3

, 108.1; Reg. 1890-1896, 105.9. Connecticut Census, 103.9; Reg. 18

3

ewis, op. c

4

ence of Marriages of Co

4

ge of Near K

4

arried his second cousin, daughter of the Duchess Sophia of Brunswick, and a descendant of William. Frederick William I married his first cousin, Dorothea, granddaughter of Sophia, and also a descendant of William t

4

ns in England and Their Effects," Journal

4

ces et des espèces." In Memoires de la

4

it.,

4

Selections Soc

4

of the deaf and dumb, blind, idi

4

of Am. Med. Asso., vol

4

sverwandschaft der Eltern a

5

b

5

f Am. Med. Asso., vo

5

f Near Kin

5

gdale,

5

, Cha

5

op. cit.,

5

op. cit

5

, Tribe o

5

by Gertrude C. Davenport, in the Ame

5

f Am. Med. Asso., vo

6

af. Special Report o

6

al Defecti

6

., p

6

cit., p. 3

6

p. cit.

6

., p

6

Jour. Stat.

6

e of Near Kin

6

op. cit.

6

p. cit.

7

p. cit.

7

op. cit.

7

ed by Feer, Der Einfluss der Blutsverwan

7

. cit.,

7

Memorials

7

pecial Report on the

7

, 1900, op.

7

, 1900, op.

7

ty upon the Organs of

7

erwandschaft der Eltern

8

be between cousins within the degree of second cousins

8

of Near K

8

of these errors. See: "Consanguineous Marriag

8

age of Near

8

upra,

8

p. cit.

8

Feer, Der Einfluss der Blutsverwandsc

8

p. cit.

8

t on the Blind an

8

he Deaf in Ame

9

on my circulars as either totally or partiall

9

arent and child) of deafness is: paternal, .54; maternal, .535. English statistics of deafness give: paternal correlation

9

t on the Blind an

9

a, p

9

to the Deaf, secon

9

und Vermischung be

9

ciology

9

on does occur in asexual reproduction. But that sex is at le

9

cit., pp

9

upra,

1

Proceedings, v

1

a, vol. i

1

e Royal Society, v

1

blance of First Cousins." Eugenics Laboratory Memo

1

e Royal Society, v

1

nd Pearson

1

ws of Inheritance in Man,"

1

., p

1

heritance in Man," part 2,

1

y of the Human Race." Memoirs of the Nation