Simple Staining Method
In Simple Staining method only one stain is used. Stain is applied to the smear in one application. The fixed smear on the glass slide is flooded with a staining solution for about one minute. The solution is then washed off with water and the slide is blot dried. The stained slide is examined under a microscope (Figure 3.6). The cells stain uniformly. The simple stains used by the microbiologists for routine purposes are dilute solutions of Methylene blue, Crystal violet, Safranin and Carbol fuchsin.
Methylene blue is more frequently used than any other stain in Bacteriology. It is used for the rapid survey of bacterial population of milk. It is also used for the diagnosis of Diphtheria. This stain is incorporated along with Eosin in Lactose Agar to distinguish Escherichia coli from other fecal bacteria in contaminated water.