It is related to resorcinol, 1,3-CH(OH). Formerly the formula consisted of chloral hydrate, menthol, veratrol, resorcinol and salicylic acid. Often orcein or a combination of resorcinol and fuchsine are used for staining. This is knot and crack free and glued with resorcinol waterproof glue. Resorcinol and sulfamic acid are also common scavenger reagents. The precursor is accessible from resorcinol through 1,3-cyclohexanedione. It glues well with epoxy resin or resorcinol adhesive. Eucalyptol forms crystalline adducts with hydrohalic acids, "o"-cresol, resorcinol, and phosphoric acid. Other drugs like sulfur and resorcinol have also been found useful in treating seborrheic dermatitis. Bilobol, another alkyl resorcinol found in "Ginkgo biloba" fruits, is also a strong skin irritant. Baeyer named his finding "resorcinphthalein" as he had synthesised it from phthalic anhydride and resorcinol. When fused with potassium hydroxide, resorcinol yields phloroglucin, pyrocatechol, and diresorcin. Unlike resorcinol it does not give a fluorescein with phthalic anhydride. Although of little commercial value, many additional routes exist for resorcinol. Resorcinol per se does not appear to occur naturally in the free state.