The watchman and southron. [volume] (Sumter, S.C.) 1881-1930, 1910-05-04
The Detection Of Blood Guilt.
People often wonder why it is th


experts, when giving evidence in
court, can so confidently affirm that a
certain substance removed from
clothes, weapons, and so on consists
of blood, although the suspected par
ties declare it to be rust or red paint
The determination of the truth is,
however matter of simple prepara-
ton and microscopical observation
which is absolutely infalibe, for rea-
sons which / will give.
The reader probably learnt at
school that all human blood consists
of two kinds of densely-p packed glo-
bules Invisible to the naked eye, call
ed corpuscles, white and red, float
ing or suspended in a liquid. I doubt
whether one person in a million
apart from those who study such top
ics-has any real idea of the min
uteness Of these objects 1t is use
less to say, for instance, that ten mil
lion of the red corpuscles will cover
square inch if laid out quite fiat.
1t is the function of the white cor
puScles to consume the bacteria and
bacilli that enter the blood and they
are actually alive. The red discs
contain the iron of the blood This
much enables us to proceed with un-
derstanding.
L squeeze a mere drop from
| needle-prick in my finger on to a
slide. At first all the globules and
discs are fairly we'll defined, though
| it is usual to add a drop of water, or
a chemical solution, to separate them
| and render them clearer Slowly the
| drop stiffens, the firmness commenc-
| ing at the edge (Which is paler than
| elsewhere) and proceeding inwards.
| Within a short time it has wholly
CONCEALED. The edge is family frilled.
while tuft-lke, darker lines, the fib-
| rim, are observable near it. The
| lengths of the tufts increase toward
tho centre of the spot in the vicinity
of which there are comparatively
large cracks dividing the film into
plates like those on a tortoise's back.
No beads are then present. This fea
ture of itself affords a good clue to
the cleverer analysis if the substance
is not too old. wait till next day be-
fore making the tests
The dried blood is eventually loos-
ened with a thin, sharp knife blade,
and comes away like fieck of india
| rubber or leather, or similar resistant
yet pliable stuff. 1 detach all except
the portion to be tested. Then I let
! fall drop of glacial acetic acid on
to the dried flake, add a tiny speck
Of common salt and gently warm the
mixture. Upon replacing it beneath
the microscope the liquor cools and
evaporates, and there strangely
springs into view a mass of red
brown crystals, or maybe scattered
ones, having definite characteristic
shapes. The chemical reactions have
been Of a very curious kind. Before
the appearance of the crystals bub-
bles of gas, etc., emerge from between
the cracks separating the minute
plates, and burst in due course. Then
the edges Of the plates become faint
er and fainter until all red tint is alb
sorbed, and the crystal. commence to
appear at various points.
The substance forming these crys-
stalls, composed of chlorine from the
salt and extractions form the blood
combined, is known as haemin, or
chloride Of haematin. The CRYSTALS
VIII undergo another change into
brown irregular particles if an al
Kali, such as soda, is added
| 1T has not only to be determined
whether a suspected substance is
blood AMI not rust or paint, but it
has to be learnt whether the blood is
that of a human being or of rab-
Dit fowl, or other creature. Fortu-
nately, the shapes Of the corpuscles
differ slightly or eXtremely.-Pro-
lessor Scott in the May Strand Maga-
| ui