17
i
Tip:
Depending on the preparation
higher magnifications do
not always lead to better
pictures.
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 to fast the objective
lens and the slide can touch
and become damaged.
7. Viewed Object –
condition and preparation
7.1. Condition
With the Barlow lens nearly fully extended
magnification can be doubled. Both
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
route (direct light principle, switch position
II). Many small organisms of the water, plant
parts and finest animal components have now
from nature these transparent characteristic,
other ones must be accordingly prepared. Is
it that we make it by means of a pre-treatment
or penetration with suitable materials (media)
transparent or thus that we cut finest wafers
off of them (hand cut, MicroCut) and these
then examine. With these methods will us the
following part make familiar.
7.2. 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/
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.
7.3. Creation of an own preparation
Put the object which shall be observed on
a glass slide and give with a pipette (Fig. 8,
22a) a drop of distilled water on the object
(Fig. 8).
Set a cover glass (in each well sorted hobby
shop available) perpendicularly at the edge of
the water drop, so that the water runs along
the cover glass edge (Fig. 8). Lower now the
cover glass slowly over the water drop.
i
Tip:
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.
DE
GB
