Castoreum a tincture in some perfumes and as a food additive. The government of Ontario pays trappers to harvest beaver castor sacs. The sacs brought between 2.62 - 5.10 Canadian dollars per ounce when auctioned at the May–June 2016 North American Fur Auction. At least 24 compounds are known constituents of beaver castoreum. Some of these have pheromonal activity. These are the phenols 4-ethylphenol and 1,2-dihydroxybenzene (catechol) and the ketones acetophenone and 3-hydroxyacetophenone. Five additional compounds noted are 4-methyl-1,2-dihydroxybenzene (4-methylcatechol), 4-methoxyacetophenone, 5-methoxysalicylic acid, salicylaldehyde, and 3-hydroxybenzoic acid. Other neutral compounds are oxygen-containing monoterpenes such as 6-methyl-l-heptanol, 4,6-dimethyl-l-heptanol, isopinocamphone, pinocamphone, two linalool
Perfume used as middle notes. Manufacturers who publish perfume notes typically do so with the fragrance components presented as a "fragrance pyramid", using imaginative and abstract terms for the components listed. Grouping perfumes can never be a completely objective or final process. Many fragrances contain aspects of different families. Even a perfume designated as "single flower", however subtle, will have undertones of other aromatics. "True" unitary scents can rarely be found in perfumes as it requires the perfume to exist only as a singular aromatic material. Classification by olfactive family is a starting point for a description of a perfume, but