Question

Why are slides prepared with negative stains not heat fixed?

A) Heat fixing enhances the negative stain effect.
B) Heat fixing kills bacteria.
C) Heat fixing prevents contamination.
D) Heat fixing is essential for negative staining.

Answer 1

Negative stains do not require heat fixing because they produce an outline or silhouette of the organisms against a colorful background.

Step-by-step explanation:

Heat fixing is not necessary for slides prepared with negative stains because negative staining produces an outline or silhouette of the organisms against a colorful background. In negative staining, the dye is absorbed by the background but not by the cells or organisms in the specimen. Therefore, heat fixing is not required as it may interfere with the negative stain effect. Instead, the negative stain can simply be applied to the slide without heat fixing.