Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1910-05-06
BLOOD GUILT.
How Experts Tell Whether Stains Are
Blood, Red Paint or Rust.

People often wonder why it is that
experts. when giving evidence in court,
can so confidently affirm that certain
substance removed from clothes, wea-
Eons, and so on consists of blood. al
though the suspected parties declare it
to he rust or red paint, writes Professor
Scott in the Strand for May The de-
termination of the truth is, however. y
matter of simple preparation and mi.
croscoplcal observation which j T, abso-
lutely infalliblc. for reasons which 1
Will give.
The reader probably learnt at school
that all human blood consists of two
kinds of densely packed globules in
visible to the naked eye. called corpus
rles. white a.! l'G, floating or suspend
ed in Il liquid. l doubt whether one
person in million--apart from those
who study such topics--has amy real
idea of the minuteness of these objects.
1t is useless to say, for instance, that
100000 of the red corpusclcs will
cover Il square incll if laid out quite
fat
1t is the function of the whit. cor
l,uScieS to consume the bacteria and
baCiili that enters the blood. and they
are actually alive. The red discs con
tain the iron of the blood. This muc,i
'nnbleS us to proceed with understand
ing.
squeeze mere drop from Il needle
prick IN my finger on to e Side AZ
first ell the glObules and discs are fair
Il well defined. though, it is usual t.
add a drop OF water, or a chemical solu-
ton. to separate them and render them
clearer. slowly the drop stiffehs. tie
f!rmness commencing ct the edge (Which
is paler than elsewhere) and proceeding
inwards Within a short time It has
wholly CONCEALED. The edge is family
f!illeG. while tuft-like. darker lines, the
fibrin. are observable near it. The
lengths e the tufts increase toward the
center of the spot, in the vicinity of
which there are comparatively large
cracks dividing the film into plates like
those on tortoise's back. No beads
are then present This feature OF Itself
affords good clue to the clevercr anal
,sis n tbs substance is not too old
wait till next day before making the
tests.
The dried blood is eventually IoJsepef;
with thin, sharp knife blade. and
comes away like f!eck of India rubber
or leather, or similar resistant yet pli-
able stuff. | detatcl, all except the Dor
ton to be tested. Then let fall a drop
OF glacial acetic acid on to the dried
flake, odd a tiny speck of common salt,
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 very curious. kind Before the
appearance of the crystals but b!es of
gas, etc, emerg from between the
cracks separating the minute plates
and burst in due course. Then the
fa'nte' until all rel tint is ahsorbeo'
and the crystals commence to arpear at
various points.
The substance forming these crystals
composed of chlorine from the sait anu
extractions from the blood, complneo' Is
known as haer1in. or chloride or haeH-
attn. The crystals will undergo anoth-
err change into brown irregular parti-
cles if an aIkali. such as soda, is added.
IT has not only Ito be determined
whether q suspected substance is blood
and not rust or paint. but 1t has to be
learnt whether the blood Is that of "a
human being or Of rabbit, fowl, or
other creature. Fortunately. the shapes
Of the corpuscles differ, slightly or ex