Stains are often used in the medical field to view how infected samples react to treatment. Since it may be difficult to follow the reactions, a dye is often used to make the process more clear. Alternatively, stains may be used on dead cells for education purposes. Different stains may be used to highlight parts of a cell so that students can see them in color. Whatever the purpose of staining a slide is, however, the reason for the staining always boils down to making it easier for the viewer to observe the specimen in some fashion.
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