French's Stain
for Elastic Fibres

Solutions

Weigert's iron hematoxylin or equivalent

Van Gieson's picro-fuchsin

French's solution
Basic fuchsin	1	g
Crystal violet	1	g
Resorcin	4	g
Ferric chloride, 30% aqu.	25	mL
Ethanol 95%	200	mL
Distilled water	200	mL
Hydrochloric acid, conc.	4	mL

Add the dye and resorcin to the water in an oversize flask.

Bring to the boil, and add the ferric chloride. Boil for 5 minutes.

Cool and filter. Dry the filter paper and beaker.

Place the precipitate and filter paper back into the flask.

Add the ethanol and heat carefully until the precipitate dissolves.

Add the hydrochloric acid. Restore to 200 mL with 95% ethanol.

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are likely to be satisfactory.

Method

1. Bring sections to water via xylene and ethanol.
2. Place into French's solution until adequately stained (may be overnight)).
3. Wash with 95% ethanol to remove excess solution.
4. Differentiate with 1% acid alcohol.
5. Wash in water.
6. Counterstain with iron hematoxylin and van Gieson.
7. Dehydrate with ethanol, clear with xylene and mount with a resinous medium.

Expected results

• Elastic fibres  –  dark blue-green
• Collagen  –  red
• Cytoplasm  –  yellow
• Nuclei  –  blue

Notes

1. This is Weigert's iron resorcin fuchsin using crystal violet and basic fuchsin instead of basic fuchsin alone.
2. It is usually recommended that the basic fuchsin should not be of the type that produces good Schiff's reagent. That is, the basic fuchsin should contain more rosanilin than pararosanilin.
3. The ferric chloride solution should be freshly made.

 

Reference
Histological demonstration techniques, (1974))
Cook, H C.
Butterworths, London, England

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