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 (Prado) into the Prado (catalogue number Catalogue Nr. E.28). The erroneous identification with Antinous generated high interest in the sculpture, with large numbers of copies being produced, largely made in Italy and Northern Europe and based on plaster casts rather than made in Spain and based on the original there. These inevitably stoked the interest by obscuring the fact that the Antinous head was in fact a restoration, instead smoothing the two into a meaningful whole (as did the casts on which they were based). Main site about copies of the Ildefonso (or Castor & Pollux) group : http://www.antinoos.info/copies1.htm Copies Castor