Articles from The Science Of Fingerprints
The Plain Arch
Jacket Folder File
The Identification Division Of The Fbi
The third and final type of case which may confront the identification
officer concerns the problem of maceration, that is, long immersion of
the fingers in water.
One of the cardinal rules for securing legible impressions is that the
fingers must be dry. Accordingly, in these cases it becomes a matter
of drying the fingers in addition to contending with other
difficulties. Usually the skin on the fingers absorbs water, swells
and loosens from the flesh within a few hours after immersion.
If an examination discloses the skin to be water-soaked, wrinkled and
pliable, but intact, the first step is to cleanse the skin carefully
as previously described. Next, wipe the fingertip with alcohol,
benzine or acetone, waiting a few seconds for it to dry. The skin is
pulled or drawn tight across the pattern area so that a large wrinkle
is formed on the back of the finger, then the bulb is inked and
If the skin is broken and hanging loose, but its pattern area is
intact, it should be removed from the finger, cleansed and placed in
alcohol or benzine (not acetone) for about a minute, then stretched
carefully over the operator's finger so as to remove any wrinkles. It
may then be printed.
Sometimes the skin is intact on the finger but so wrinkled and hard
that it is not possible to draw it tight for inking. In this case it
may be advisable to inject tissue builder to round out the bulbs for
inking and printing. Should this fail, the ridge detail is
photographed on the finger; or the skin is cut off, flattened between
two pieces of glass and then photographed. Here, again, it must be
pointed out that when the ridge detail does not show on the surface of
the outer skin the underside should be examined, for many times the
detail can be seen clearly. Should this be true, of course, the
underside is photographed.
In cases where it is noted that the outer skin is gone and the finger
is not saturated with water, it is possible to dry the surface
sufficiently for inking and printing purposes by rolling the finger on
a blotter. If this fails, the finger is wiped off with a piece of
cloth which has been saturated with alcohol, benzine or acetone, after
which it may be inked and printed.
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