Abstract
The effect of basic polysaccharides on the staining characteristics of acidic polysaccharides in tissue sections of formalin-fixed paraffinembedded material has been studied. Acidic polysaccharides ordinarily do not stain with acidic dyes, but stain well with basic dyes. The complex formed when a basic polysaccharide such as Aspergillus polysaccharide or deacetylated chitin reacts with acidic polysaccharides assumes the staining characteristics of the basic polysaccharide, that is, it stains with acidic dyes. Thus, areas in tissue sections containing acidic polysaccharides can be colored with acidic dyes. Further, the basic polysaccharides were shown to temporarily block staining of acidic polysaccharides by alcian blue and mucicarmine.