Alcian blue 8GS: a new stain for mucin.

1. Doubtful specificity. Not only mucins accept the stain; other elements such as nuclei, connective tissues, &c, may do so as well. 2. Loss of stain. In some cases where mucin is stained in a specific manner by dilution of the stain used, by adjustment of the pH of the stain solution, or by metachromatic properties of the stain, it is frequently difficult or impossible to dehydrate, clear, and mount the section without either immediate or later loss of the stain. 3. The stained mucin may have other stains added to it during additional operations. 4. The staining methods may be involved or may require the making-up of reagents which are often unstable.