Cytology 03

For this image the spleen section was stained with Eosin, which is an acid dye. Acid dyes bind to basic substances (acidophilic), which, in the "typical" cell equates to protein. So Eosin stains preferentially regions that are rich in protein and "poor" in nucleic acids, such as mitochondria. At the cellular level, red blood cells (rbcs), having no nuclei or ribosomes (at least not in humans), are quite eosinophilic. Since the spleen "filters" blood, there are regions in the spleen (not just the blood vessels) that have many rbcs and are quite eosinophilic, as seen here to the upper right.

Slide A-2, field 17-P of finder slide A, 16X objective