(R23) Mayer’s hematoxylin


-     Hematoxylin crystals                                                 1 g

-     Potassium alum                                                       50 g

-     Sodium iodate (NaIO3)                                          0.20 g

-     Chloral hydrate                                                        50 g

-     Distilled water                                                    1000 ml


­       Melt (at ~90 °C) the hematoxylin and potassium alum in 500 ml distilled water, allow to cool;

­       Add the sodium iodate previously dissolved in 50 ml distilled water and the chloral hydrate dissolved in 450 ml distilled water;

­       Allow to “ripen” in an incubator for 48 hours at 48-50 °C, in a sealed glass container;

­       Remove from the incubator, uncover (or transfer to an unsealed container), and allow to cool, mixing slowly and evenly with a magnetic stirrer for about two hours.

­       Add 5 ml glacial acetic acid and stir well.

­       Filter before use.

Mayer's hematoxylin solution is stable for at least a year if stored in a dark glass bottle at room temperature (20-25 °C). 

Hematoxylin solutions (Heidenhain, Mayer) are commercially available, but are often not properly “ripened” (oxidized). If this is the case, the parasites are only weakly stained and nuclear details are poorly differentiated.