Hematoxylin (Harris)
Haematoxylin (Harris) is used for general purpose nuclear stain and for histological studies. Haematoxylin and eosin are the principle stains used for the demonstration of nucleus and the cytoplasmic inclusions. Alum acts as a mordant and haematoxylin containing alum stains nucleus light blue which turns red in the presence of acid. The cell differentiation is achieved by treating the tissue with acid solution.