TYPES OF MICROSCOPES

IDENTIFICATION OF BACTERIA (STAINING)

Not all specimens can be clearly seen under a microscope. Sometimes the specimen blends with other objects in the background because they absorb and reflect approximately the same light waves. You can enhance the appearance of a specimen by using a stain. A stain is used to contrast the specimen from the background.

A stain is a chemical that adheres to structures of the microorganism and in effect dyes the microorganism so the microorganism can be easily seen under a microscope. Stains used in microbiology are either basic or acidic. 

To stain an organism, a scientist needs to know how to make a smear. The following describes how a smear is made –