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
Castor and Pollux first. Castor and Pollux agreed. Idas quickly ate both his portion and Lynceus' portion. Castor and Pollux had been duped. They allowed their cousins to take the entire herd, but vowed to someday take revenge. Some time later, Idas and Lynceus visited their uncle's home in Sparta. The uncle was on his way to Crete, so he left Helen in charge of entertaining the guests, which included both sets of cousins, as well as Paris, prince of Troy. Castor and Pollux recognized the opportunity to exact revenge, made an excuse that justified leaving the feast, and set out to steal