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
Cybernetics: Or Control and Communication in the Animal and the Machine derived from Maltz's work. "Cybernetics" became a surprise bestseller and was widely read beyond the technical audience that Wiener had expected. In response he wrote "The Human Use of Human Beings" in which he further explored the social and psychological implications in a format more suited to the non-technical reader. In 1954, Marie Neurath produced a children's book "Machines which seem to Think" , which introduced the concepts of "Cybernetics", control systems and negative feedback in an accessible format. Cybernetics: Or Control and Communication in the Animal and the Machine Cybernetics: Or Control and Communication in the Animal and the