CONSANGUINEOUS MARRIAGE 
Subject Often Regarded by Unscientific Methods of Thought and Effects 
Misunderstood—Consanguinity in Itself Probably Has no Genetic Impor- 
tance—The Hereditary Traits Are the Things To Be Considered— 
Marriage of Kin May Be Either Good or Bad in Effect 
? 
THE EDITOR 
OW often have we been told of 
H those “isolated communities 
where consanguineous marriage 
has led to an appalling amount of 
defect and degeneracy!’ Any one of 
us could name a dozen of these “‘horrible 
examples” offhand. Without question- 
ing the facts, one may question the 
interpretation of the facts, and it seems 
to me that a wrong interpretation of 
such stories is partly responsible for the 
widespread and almost superstitious 
misunderstanding of consanguineous 
marriage at the present time. 
The Bahama Islands furnish one of 
the stock cases, and Dr. W. C. Rucker 
has just put in my hands a copy of 
Dr. Clement A. Penrose’s account of 
the situation there.1_ What the traveler 
says has a very familiar sound: 
“In some of the white colonies where 
black blood has been excluded, and 
where, owing to their isolated positions, 
frequent intermarriage has taken place, 
as for instance at Spanish Wells, and 
Hopetown, much degeneracy is present, 
manifested by many abnormalities of 
mind and body... «: Lam strongly 
of the opinion that the deplorable state 
of degeneracy which we observed at 
Hopetown has been in a great measure, 
if not entirely, brought about by too 
close intermarrying of the inhabitants,” 
and so on. 
To demonstrate his point, he took the 
pains to compile a family tree of the 
most degenerate strains at Hopetown. 
There are fifty-five marriages repre- 
sented, and the chart is overlaid with 
twenty-three red lines, each of which is 
said to represent an intermarriage. 
1 Penrose, Clement A., ‘‘Sanitary Conditions in the Bahama Islands.’ 
of Baltimore, 1905. 
This looked like a good deal of con- 
Sanguineous mating, but I thought I 
would test the matter a little further, so 
I started with the fraternity at the 
bottom of the chart—eight children, 
of whom five were idiots—and traced 
out their ancestry. In the second 
generation it ran to another island, and 
when the data gave out, at the fourth 
generation, I was a little surprised to 
find that there was not a single case 
of consanguineous marriage involved. 
I picked out another fraternity con- 
sisting of two men, both idiots and 
congenitally blind, and a woman who 
had married and given birth to ten 
normal children. In the fourth genera- 
tion this pedigree, which was far from 
complete, went out of the islands; as far 
as the data showed there was not a 
single case of consanguineous marriage. 
There was one case where a name was 
repeated, but the author had failed to 
mark this as a case of intermarriage, 
if it really was such. If we assume that 
it was a first-cousin marriage, yet 
almost any one of us may have one 
first-cousin marriage in the preceding 
four generations of his pedigree. I am 
unable to share the conviction of Dr. 
Penrose, that in the two pedigrees 
which I investigated, we have an 
example of the nefarious workings of 
intermarriage. 
CONGENITAL BLINDNESS 
Finally, I traced out a fraternity to 
which the author had called particular 
attention because three of its eleven 
members were born blind. The defect 
was described as “optic atrophy asso- 
Geographical Society 
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