The diameter of Micrococcus luteus appears different when comparing this bacteria in two different stains. Although the magnification was the same for both--the Micrococcus luteus appeared larger in diameter when stained with the negative acidic stain. There are a couple of reasons this happens. 1. Heatfixing shrinks cells to some degree in the basic stain. 2. The acidic stain only stains the background of the smear, making cells with capsules appear larger.
