Negative
Staining
Technique
Negative
Staining
Techniques
works
in
a
manner
opposite
to
simple
technique.
Bacteria
are
mixed
on
a
slide
with
an
acidic
dye
such
as
congo
red
or
the
black
stain,
nigrosin.
The
mixture
is
smeared
across
the
face
of
the
slide
and
allowed
to
air
dry.
Because
he
stain
carries
a
negative
charge,
it
is
repelled
by
the
bacteria,
which
also
have
a
negative
charge.
The
stain
gathers
around
the
cell.
since
a
chemical
reaction
has
not
taken
place,
and
because
heat
fixing
has
been
avoided,
the
cells
appear
less
shriveled
or
distorted.
They
often
appear
larger
than
stained
cells
and
more
natural.
