Bresser BIOLUX NV Mode D'emploi page 20

With changing magnification (eyepiece or
objective lens changes, pulling out of the
Barlow lens) the sharpness of the image must
be newly defined by turning the focusing
wheel (Fig. 1, 9).
nOTe:
Please be very careful when
doing this. When you move
the mechanical plate upwards
too fast the objective lens
and the slide can touch and
become damaged.
8. Viewed Object –
condition and preparation
8.1. Condition
With the Barlow lens nearly fully extended
magnification can be doubled.
transparent and non-transparent specimens
can be examined with this microscope,
which is a direct as well as transmitted light
model. If opaque specimens are examined
- such as small animals, plant parts, tissue,
stone and so on - the light is reflected from
the specimen through the lens and eyepiece,
where it is magnified, to the eye (reflected
light principle, switch position I). If opaque
specimens are examined the light from
below goes through the specimen, lens and
eyepiece to the eye and is magnified en
20
route (direct light principle, switch position
II). Many small water organisms, plant parts
and the finest animal components have
natural transparent characteristics others
need to be prepared accordingly. Preparation
can take many forms such as the soaking in
appropriate substances (medium) to make
the object opaque. Objects can also be finely
sliced (hand cut, micro-cut). The following
sections explain these procedures in detail.
8.2. Creation of thin preparation cuts
Specimens should be sliced as thin as
possible, as stated before. A little wax or
paraffin is needed to achieve the best results.
A candle can be used for the purpose. The
wax is put in a bowl and heated over a flame.
The specimen is then dipped several times in
the liquid wax. The wax is finally allowed to
harden. Use a MicroCut (Fig 2, 24) or knife/
Both
scalpel (carefully) to make very thin slices of
the object in its wax casing.
DANGER!
Be extremely careful when
using the knives/scalpels
or the MicroCut. There is an
increased risk of injury due to
the sharp edges!
These slices are then laid on a glass slide and
covered with another.
8.3. Creation of an own preparation
Put the object to be observed on a glass
slide and add a drop of distilled water using a
pipette (Fig. 8, 22a) onto the object (Fig. 8).
Set a cover glass (available in most well
stocked hobby shops) perpendicularly at the
edge of the water drop, so that the water runs
along the cover glass edge (Fig. 8). Now
lower the cover glass slowly over the water
drop.
Tip:
i
The gum medium supplied
(Fig 2, 25b) is used to make
permanent slide cultures.
Add it instead of distilled
water. The gum medium har-
dens so that the specimen
is permanently affixed to its
slide.