Specimen needs to be as thin as possible
Before any specimen can be examined under the microscope, a slide has
to be prepared. No matter how good your microscope is, the final image
can only be as good as the slide you are viewing, so proper preparation
A normal compound microscope works by passing light up through the
viewed specimen, so it is important that the sample or specimen is a
thin as possible. This means working with relatively small amounts
of algae, mucus, sediment or whatever. This is particularly important
when viewing mucus sample as some of the smaller, transparent parasites
might not be seen if the preparation is too thick.
Slide and cover glass
Ideally a new slide and cover glass should be used for each
preparation, but in practice slides and slips will be re-used many
times. In which case it is important that they are clean and free
of smears ( cleaning with alcohol will help remove smears - propan-2-ol
from a chemist or drug store).
The specimen is placed, together with
one drop of pond water onto the centre of a clean slide. Do not use
tap water or distilled water as these may kill any parasites
present. If the specimen is thick, use a seeker needle to
gently spread it as thin as possible.
A glass or plastic cover slip is then
lowered gently on top making sure that no air bubbles are trapped.
The best way to place a cover slip is to hold two opposite edges
between first finger and thumb. Holding the slip at a 45o
angle, place the bottom edge on the slide just to one side of the
specimen and then slowly lower the cover slip until it is
flat. You can use a seeker needle to help lower the slide by
placing it under the cover glass and slowly lowering it into
Once the cover slip is in position
apply a small amount of pressure with a seeker needle to spread the
sample under the slip and squeeze out any air. Don't apply too much
pressure; just enough to spread the sample. Do not use your
finger as a finger print may contaminate the cover glass.
Practice makes perfect - so try making
slides of all sorts of things; blanket weed, algae, mulm etc.