Ehrlich’s hematoxylin

100 mL H₂O

100 mL ethanol (100%)

100 mL glycerol

10 mL glacial acetic acid

2 g hematoxylin

Aluminum potassium sulfate (alum; AlK[SO₄]₂•12H₂O) (to excess)

Combine above reagents and mix. The “excess” of alum means enough to make a saturated solution, with undissolved material in the bottom of the bottle. This is Ehrlich’s original formulation. It is often misquoted, with a smaller amount (10 g) of alum. The solution is ready to use in ~1 mo, when it is dark red. The solution can be used repeatedly for several years.