Define method Used for Capsular Staining - Anthony Staining Method?
Another method used for capsular staining is Anthony staining method, devised by E.E. Anthony in 1931. The method involves the use of a primary stain i.e., 1% aqueous crystal violet. Both the capsular material and the cell wall will take the colour of the stain and will appear dark blue. But the capsule being nonionic will not absorb the primary stain. It adheres to the capsule without binding to it. Because capsule is water soluble, therefore, copper sulphate is used both as a decolourizing agent and as a counter stain. It takes out the colour from the capsular material and counter stains the decolourized capsule which now appears as a light blue zone surrounding deep purple cells. In both Klebsiella and Bacillus, capsule can be seen surrounding the dark purple coloured cells. Capsule will appear as a clear zone in negative staining against dark background, whereas, it is light blue coloured in anthony's method.