PERSISTENCE OF PATTERNS
A human finger, in ordinary circumstances, may preserve, unimpaired,
not only its general pattern of lineations, sometimes very intricate,
during its owner’s lifetime, but the minutest details also may be
discerned after thirty or forty years, quite unchanged as elements
of a pattern, and very likely for a longer period, though scientific
observation has not extended much beyond that limit. Long immersion,
after death, in water, till the skin is quite sodden, does not readily
destroy, does not even greatly obscure, the lineations for the purpose
of comparison with earlier printed records of them, and one can still
read into finger-print type, so to speak, the lineations of an Egyptian
mummy.
When first I ventured to call the attention of the scientific world to
the patterns of finger-prints in 1879 or 1880, I suggested that the
ancient mummies of Egypt might possibly be found to have retained those
features sufficiently to be studied. I had no opportunity of obtaining
access to such remains in order to test the point, but on returning
to England I found that anticipation to be amply justified, as anyone
may verify by a visit to the British Museum. The skin of a mummy is
contracted, hard, and wrinkled, but one may trace the lineations
through all their loops, joinings, ramifications and whorls, with
great distinctness. So that it follows, did an Egyptian register of
finger-prints exist, we might unearth the names and titles or deeds of
some of those men who lived several thousands of years ago.
There is nothing, so far as has yet been observed, to mark their
race out as essentially different from our own, nor do any ancient
finger-prints look unlike those of present-day people’s.
The ridges on toes and fingers are visible in children born
prematurely, even at a very early period, as I have observed in the
practice of my profession, and as soon as the lineations are at all
discernible they are of human type. So far as has yet been observed,
we do not find that the growing human embryo repeats a history of
finger-patterns, beginning at an earlier and lowlier biological stage,
as is sometimes contended to be the case in regard to some other
organic structures undergoing development.
The efforts I first made to investigate the problem of permanence were
chiefly directed to the earlier periods of life, as presenting the
greatest likelihood of variation in patterns during rapid growth. A
large number of Japanese children, and also some thirty-five or more
children of European parentage, in ages from five to ten, were minutely
examined time after time during a period of two years--some of them
again at longer intervals--without a single variation being detected.
The lines and patterns in the fingers of growing children broaden out
as the infant grows, but the ideal form--so to speak--of the pattern
itself, retains full sway. To grasp this conception clearly is almost
the whole science of finger-print identification.
During that period, some of those children suffered severely from
scarlet fever, which, as a new disease, took a severe form in Japan,
and the desquamation, or skin-peeling, was unusually severe, so that
in those cases the test was a severe one. On several occasions I have
called attention to the possibility of severe desquamation being
followed by some change of patterns, and I still think this subject
merits the attention of medical men, but no actual fact illustrating
the apparent danger has yet been brought under notice. This may,
however, be simply the result of a high degree of inattention to a
subject which medical men do not seem to have interested themselves in
until very recently. In acromegaly, a disease in which the fingers take
on gigantic features, one might expect to find a very notable change
of patterns, perhaps the addition of fresh lineations, but after some
attempts to collect information not one single example of the kind has
yet reached me.
Besides testing growing children in the manner I have stated, many
Japanese medical students between the ages of twenty and thirty were
made use of in this way. The ridges were carefully shaved by razors,
or smoothed away by sand-paper, emery dust, or pumice stone, so that
no distinct patterns could be traced. The same tests were applied to
my own fingers and to those of one or two medical friends who were
quite sceptical as to the continuity of the patterns. Many of the
patients at the hospital, or out-door dispensary, were also induced
to submit, but not a single instance of variation in the patterns was
ever brought to light. My own fingerprints have not varied since that
date, a period of fully thirty years. However smooth the surface had
been made, the old design came up again with perfect fidelity, yielding
exactly the same imprints as before, subject only to those very minor
variations already described in a previous chapter, to which even
engravings are subject. Up to the period of my final return to England
in 1887, a period of nearly nine years, enthusiastic and vigilant
observation of this point gave me complete confidence in the permanence
of finger-print patterns as a basis of personal identification. With
the exception of acromegaly and skin-peeling after acute fevers, I
can conceive of no biological reason why changes might be anticipated
in those patterns, and up to the present no evidence has reached me
that even those conditions do effect pattern changes. In old age the
ridges shrink somewhat, and wrinkles here and there betray the drying
up of tissues, which facts are revealed in printed impressions by fine
white lines, often cutting across the lineations, not unlike those
which occur in box-wood engravings, where hair-like lines betray some
cleavage of the wood. In such a case the value of the pattern is not
affected as a proof of identity. One may go beyond that, and say that,
if after a lapse of forty years or so the old pattern is now crossed
by wrinkles which were not there in youth, the two prints are from the
same individual.
Other observers--Sir Francis Galton, Sir William Herschel, and the
police of this and other countries--have accumulated a vast store of
conclusive evidence on this point.
We are now amply justified in assuming that, for all practical purposes
of identification, the patterns on human fingers are, throughout life,
persistent and unchangeable. Such slight and transient changes--not due
to mere variations of pressure, inking, and the like, as they usually
are--are no more likely to invalidate an identification than a new
freckle or pimple on a man’s face would make him unrecognizable by his
intimate friends.
Dr. J. G. Garson, in an article in the _Daily Express_ of July 20th,
1905, writing on this subject, which he has carefully studied, said:--
“It is now a well ascertained fact that every person bears on his
fingers as certain proof of his identity as he does on his face.
The latter is, however, that part of his anatomy by which he is
most readily identified by the world at large, though to his
intimate friends other particulars about him may characterise him
equally strongly. By means of the eye, the _tout ensemble_ of the
countenance is registered upon the mind, generally regardless of
details respecting the actual form of each particular feature--in
short, a person is recognized and identified by exactly the same
psychological process as a printed or written word is read without
first spelling it.”
It must be clear to any student of the subject that _persistence of
patterns_ must become the basis of identification in this way, and
that persistence is now as firmly established as anything can be as to
living creatures.
Sir Edward Henry, in his _Finger-Prints_, says (p. 17, 3rd edition):
“Impressions being required for permanent record, their utility must,
in great measure, be contingent upon the persistence through long
periods of time, of the general form of the pattern and of the details
of the ridges constituting it.” No such stability has yet been shown
to exist in regard to any other part of the body. The bones change
very greatly, not only in size, but in shape, texture, and mechanical
conditions through life. Even the ordinary features and expression of
a human being by no means can be said to remain uniform. One sees
a friend during many short intervals, and is not finely observant
of minute changes that in a decade or two amount collectively to an
almost complete transformation of the man’s whole face and figure. The
photographic system of identification, although serving a purpose now
and then, was found, therefore, to be untrustworthy.
My revered teacher, Lord Lister, noted the slow migrations of the
pigmentary particles that make the web-like patterns on a frog’s foot.
I have observed similar but still slower changes in ordinary freckles
on a human hand. The white spots of leucoderma--a skin-disease that
used to be confused with leprosy, from which it entirely differs--are
often bounded with dark borders, into which the pigment particles have
migrated from the white spots. A negro’s skin sometimes becomes white
where a fly-blister has been applied, as a fair-skinned person is often
marked with a dark patch after a similar application. The pigment
particles move to and fro like living things, though very slowly, and
the marks they collectively make on a living body are not fixed and
stable. Again, we have seen that the police used to record the position
of wens, tumours, tattoo marks and the like. But tumours are now often
removed through the line of natural creases, or wrinkles, leaving very
faint traces, if any, behind.
An official in Japan had a large wen on his forehead, which disfigured
him greatly. He was getting elderly, and told me, when friends brought
him, that he would as soon have the wen as a scar. I got him to consent
to have it removed through the natural wrinkle in the forehead, after
which it left no visible trace at all.
A curious case was that of a man whose back and shoulders were adorned
by a large collection of a certain kind of tumour varying from the size
of a chestnut to that of a hen’s egg. They all disappeared, without the
use of the knife, leaving no scar behind, and only a slight lowering
and thinning of the skin.
Even scars, themselves, sometimes very unsightly ones, tone away to
a large extent, till they cease to be at all conspicuous. The colour
of the hair changes greatly in some people at the various stages of
life. Certain diseases, too, such as malarious affections, the action
of the sun, and certain employments, change the complexion in a very
remarkable way.
What the pole-star used to be in navigation, fingerprint patterns are
now become for all serious purposes of practical identification.