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 Castor (Alpha Geminorum) and Pollux (Beta Geminorum). As emblems of immortality and death, the Dioscuri, like Heracles, were said to have been initiated into the Eleusinian mysteries. Castor and Pollux are consistently associated with horses in art and literature. They are widely depicted as helmeted horsemen carrying spears. The Pseudo-Oppian manuscript depicts the brothers hunting, both on horseback and on foot. On votive reliefs they are depicted with a variety of symbols representing the concept of twinhood, such as the "dokana" (δόκανα – two upright pieces of wood connected by two cross-beams), a pair of amphorae, a pair of shields,