Transfer the sample to a 1000-mL Erlenmeyer flask and add 500 mL of boiling distilled water. Heat the flask for 1 h in the hot water bath.Cover the flask with a watch glass to prevent evaporation.Keep the water at boiling temperature and surround the flask in the bath with boiling water.After extraction,filter on a Buchner funnel through a Whatman No.5 filter paper or equivalent and wash with 500 mL of boiling distilled water.Allow the wood to air-dry thoroughly.