5µ paraffin sections of neutral buffered formalin fixed tissue are suitable.
Other fixatives are likely to be satisfactory. Cryostat sections usually show brighter metachromasia.
Unmounted frozen sections may also be floated in each solution and mounted on a slide just before coverslipping.
Bring sections to water via xylene and ethanol, except for cryostat and frozen sections.
Place into crystal violet solution for 2-5 minutes.
Rinse well with water and examine microscopically.
If necessary, differentiate in dilute acetic acid until amyloid is red and contrasts well with the tissue.
Wash very well in tap water, about 5 minutes.
Drain all water from the slide until just damp and mount with Highman's medium.
Ring the coverslip to inhibit evaporation of the mounting medium and precipitation of the ingredients.
Amyloid – purple-red
Background – Blue-violet
Nuclei – Blue-violet
Methyl violet may be used instead of crystal violet if preferred.
Highman's gum syrup is a modification of Apathy's gum syrup and contains: Water 50 mL Gum Arabic 25 g. Sucrose 25 g., and either potassium acetate 25 g., or sodium chloride 10 g. These last two salts help to stop bleeding of the dye into the mounting medium.
Reference Drury, R A, and Wallington, E A, (1967). Carleton's histological technique., Ed. 4, p. 222.
Oxford University Press, London, England.