First of all, it is very difficult to see bacteria under the microscope. Chances are you’ll need to use at least 400x, meaning your 10x eyepiece and your 40x objective. More than likely, you might need to use the 100x objective with oil immersion.
We had a leak in the living room ceiling, and traced it back to the seal under the upstairs toilet. I took a sample of the leakage water, and then replaced the wax seal under the toilet. I found the below pictured bacteria in the water.
In order to see bacteria, you’ll need to stain the specimen or use a contrast method. I used phase contrast at 400x.
The above picture was taken with a digital camera at an exposure of 1/2 second at f4.8
There are several types of bacteria, and since many of them can be dangerous, I have not spent a lot of time on the subject. I did, however, discover the rare forms below.
These long, brightly colored forms are known to have a black inside made of licorice, and and outer coating of candy. The round shaped forms have both a sweet and tart taste in the mouth. If you injest these, be sure to brush your teeth thoroughly afterwards.