Hello Aspirant,

See there are two types of Bacteria, one is Gam-Negative Bacteria and other is Gram-Positive Bacteria. The method which is used to classify or differentiate them on the basis of physical and chemical properties of their cell wall is called as Gram-Staining or Gram stain or Gram's method.

This technique was developed by the Danish Bacteriologist named Hans Christian Gram and this technique is found commonly in different Laboratories.

I hope this information helps you.

Good Luck!!