Demonstration of the bacterial cell wall in stained smears

Abstract

The method proposed by Robinow & Murray (Scanga, 1959), to demonstrate the cell wall of bacteria is quite seletive for Gram positives but, when applied to Gram negatives, all the cell becomes evenly stained. The method proposed by Knaysi (1941) althought offering a better contrast is of very delicate performance, to be practical. In this paper, the AA. present a new staining method in order to offer a good contrast between the cell wall and cytoplasmic material. Essentially it consists in turning citoplasmic material unstainable by treatment of the cells with a acid mordent. The subsequent stainning with malachite green or Victoria blue gives a very good contrast. The method can be applied either to Gram positive or Gram negative bacteria.