A Hematoxylin solution that is commonly used progressively and very rarely used regressively is called which?

• A. Mayer's
• B. Harris'
• C. Gill's
• D. Weigert's

Answer: (A)

The concept here is how hematoxylin is used to stain nuclei: progressively, without a post-stain differentiation step, or regressive with an acid-alcohol differentiation to sharpen the stain. Mayer’s hematoxylin is the classic formulation designed for progressive staining. It develops a uniform, reliable nuclear stain as the tissue sits in the solution, and it’s typically left to develop to the desired intensity without a separate differentiation step. That makes it the standard choice in many routine H&E protocols because you get consistent results with less manual adjustment.

Other hematoxylins have different typical uses. Harris’ hematoxylin is more commonly associated with regressive staining, where differentiation is used to control staining intensity. Gill’s and Weigert’s formulations have their own specialized applications, but they’re not the standard progressive choice like Mayer’s.