Gram stain modified to improve colour contrast.

Gram stain modified to improve colour contrast One of the disadvantages of Gram stain is that the final Gram counterstain colours not only the Gram-negative material but also all the other background material in the preparation.A modified technique has been developed to improve colour separation and to eliminate much of the unwanted background Gram-negative stain.The basis of the modification to be described is Preston and Morrell's (1962) Gram staining method.The procedure is as follows:Take the section to water.Take 4 g