Why do you have to wet mount when looking at bacteria?

Answer 1

You don't have to make a wet mount when looking at bacteria, unless you need them to be alive! Typically we use a wet mount to look for motility (movement) and to observe the cells at their normal shape (if you use an isotonic 'wetting' agent).

The other way we view bacteria is to stain them, but this process kills them and usually distorts the shape of them slightly.

Answer 2

Do you mean when making a microscope slide to look for bacteria? If so, we do a wet mount so that the bacteria/organisms we want to look for don't shrivel up and become unrecognizable under the microscope.