Salicylaldehyde be prepared from the corresponding phenol by the Duff reaction, or by treatment with paraformaldehyde in the presence of magnesium chloride and a base. Salicylaldehyde was identified as a characteristic aroma component of buckwheat. It is also one of the components of castoreum, the exudate from the castor sacs of the mature North American beaver ("Castor canadensis") and the European beaver ("Castor fiber"), used in perfumery. Furthermore, salicylaldehyde occurs in the larval defensive secretions of several leaf beetle species that belong the subtribe Chrysomelina. An example for a leaf beetle species that produces salicylaldehyde is the red poplar leaf beetle
Pith and substance to one of them will deal with the issue. For example, if the provision in question has no relation to the regulatory scheme, the question of its validity may be quickly answered on that ground alone. The pith and substance doctrine as applied in the jurisprudence of the Judicial Committee of the Privy Council, effectively the British Imperial Court of Appeal, has been carried to other Commonwealth federations. It is used in the Indian Constitution. It was also used in Northern Ireland under the Government of Ireland Act 1920. The substance of the doctrine has been cast in statutory form