522 The Journal of Heredity 
and consequently covered by a few 
more ridges in one than in the other.”’ 
“This occasional wide discrepancy 
in the number of ridges suggests that 
we are on the border between character- 
istics which are duplicated [in duplicate 
twins] and those which are not. While 
the correspondence between the main 
lines and areas, the patterns and other 
figures, and even the number of ridges 
in most cases is nothing short of remark- 
able, the law seems to fail at about the 
latter point, and if we turn to the 
‘minutiae’ of the ridges,® that is, the 
forkings, interruptions, interpolations 
and isolations, we find that the limit 
of resemblance has been passed, and 
that whatever law of heredity or of 
construction has caused a similarity of 
form or arrangement in the larger parts, 
it is here no longer binding. Perhaps in 
this way we may be led to approximate 
the question asked by Galton, ‘What is 
the minutest biological unit transmissi- 
ble by heredity?’, since in individuals 
that arise from one egg and thus possess, 
presumably, the same inheritance, the 
main lines, areas, patterns and other 
large features are duplicated exactly, 
or as nearly as the ridges will allow 
them to be, while the ridges themselves 
with their minutiae are not.” 
PRINT OF A SPLIT FINGER 
A striking evidence that the minutiae 
are not due to heredity was discovered 
by Wilder when he observed a man 
with six fingers, one of the original 
five having split in the course of 
development. The pattern of these two 
finger-tips, which in origin were halves 
of the same finger, was not identical. 
Given the hereditary basis of finger- 
patterns, it might be expected that 
different races would differ in this 
characteristic. Galton, however, con- 
cluded from a study® of English, Welsh, 
Hebrew, Basque and Negro finger prints 
that “‘there is no peculiar pattern which 
characterises persons of any of the above 
races.’’ Prof. Wilder has made an 
interesting study’? of negro and white 
palm and sole prints, and finds that here 
distinct races have distinct racial formu- 
lae, which are characteristic but not 
invariable. No pattern was found among 
negroes, which could not be duplicated 
among whites; yet a certain pattern 
was more common among negroes and 
another among whites. Further, there 
was found much more individual varia- 
tion among the whites than the negroes, 
the latter exhibiting only sixteen differ- 
ent patterns, while the whites disclosed 
forty-four. It is probable that the 
negro tends to be more primitive in this 
respect than does the white race. 
There appears to be no constant differ- 
ence between the two sexes in respect 
of friction-skin patterns, but Ch. Féré 
believes he has found some differences 
which are correlated with intelligence. 
When taking the hand prints of idiots, 
he found that in many cases their left 
thumbs were not wholly opposable.' 
He further observed that the most 
complex forms of finger-print patterns 
are on those digits which are most 
differentiated functionally: 7. e., the 
thumb and first finger, and the great toe. 
Finally he states,!* but without adequate 
evidence, that “there is a correlation 
between the complexity of the patterns 
of the papillary crests and the develop- 
ment of the intellect and senses.”’ 
The problem of working out the exact 
mode of inheritance of friction-skin 
patterns appears at present to be 
almost hopeless; certainly Wilder’s hy- 
pothesis that they are due to “two or 
more Mendelian factors’ is not yet 
proved. But the study is full of interest 
and offers promising results not only 
to geneticists, but to taxonomists, 
morphologists and ethnologists, as well 
as policemen. And as Wilder points 
out, ‘Unlike most biological material, 
that concerned here is readily obtained, 
8 To those engaged in finger-print identification, these minutiae are known as “ridge charac- 
teristics,”’ and classified as abrupt beginnings and endings of ridges, bifurcations, islands, etc. 
* Finger-Prints, by Francis Galton. London, 1892, Chapter XII. 
10 American Anthropologist, Vol. xv (1912), pp. 189-207. 
11 Comptes rendus de la Société de Biologie, Tome 50, p. 827. 
12 Thid., Tome 48, p. 1115. 
18 Biological Bulletin, Vol. xxx, No. 3, March, 1916. 
to this paper. 
There is a good bibliography attached 
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