How to isolate an amoeboid?
Sometimes it might be useful to isolate a specimen for a specific purpose. You can use a stereomicroscope for that, but an inverted microscope is much more handy.
My main instruments are fine needles and micropipettes. I use very fine insect-needles which I attach to small wooden sticks. Micropipettes can be made from glass tubes. I hold one in a gas flame till it softens. Then I move both ends away from each other until a long thin wire is formed. You can easily break or cut this wire with a knife or scissor. In fact you have got two pipettes. Usually the thin ends are not hollow. Look where it is hollow, and cut it there again. Put a balloon at the other end and you are ready to go! Not every pipette has a very narrow end. You have to practice somewhat to find a good one. Glass tubes, balloons and insect-needles can be ordered; they are really cheap.
I use small plastic petri dishes for scanning my samples fast. If there is an interesting amoeboid, I use a pipette to catch it. I empty the pipette on a slide and observe the slide with my stereo/inverted microscope.
As a result the wanted amoeboid is now captured in a small drop (see drawing below, A). With a pipette I bring a small drop of distilled water (B) beside the drop with the amoeboid. I use a needle to move the amoeboid to the edge of the drop and with a quick movement I sweep it out of its drop. During this sweep the amoeba is still in a small drop (B) between the old drop and the distilled water drop. I move the needle further so the amoeba comes into the distilled water. In fact it’s one uninterrupted move from A till C.
If other organisms come along with it, I repeat the procedure, until the amoeba is home-alone in a drop. I suck up the older drops with a tissue and add a little water to the drop with the isolated specimen. The reason is that I can more easily suck it up and transfer it to e.g. a culture dish or a tube.
It looks more difficult than it is. You need some patience and some exercise.