What beavers, botanists, sugar, and Greek gods have in common with Popeye and Castor Oil might be totally limited to the spelling “castor” (Gr. kastor), but that commonality has led to confusion in many quarters. Let’s sort things out.
We start with the mythical Greek half-twin brothers Castor and Pollux (the Dioscuri), who might be more familiar in their Latin identity as stars of Gemini, an astrological constellation in which Castor an Pollux are the most visible points of light. Linking the stars to Greek stories is normal, and tales describe the half-brothers as patrons to travelers and sailors, forces to which mortals can appeal in times of crisis. The twins and the stars seem to have no connection to Castor Oil.
Another Castor is Antonius, an early botanist lauded by Pliny and credited as source of important herbal information, as well as the owner of what would be the first documented Western medicinal and botanical garden. No connection there with Castor Oil, though the relationship of a famed herbalist to a powerful plant is tantalizing.
In yet another vein, at some point it seems the Greek word Castor became associated with European Beavers (Castor fiber), even though the industrious rodents are not native to the Mediterranean, and have zero relationship to the Gemini. And beavers are the source of Castoreum, an oily, curiously pleasant vanilla-like fragrance used in perfumes and food products. But do not confuse the unctuous Castoreum, which is harvested from Beaver anal glands, with Castor Oil; they bear no resemblance in origin, use, or chemical composition.*
A Wikipedia page directs us to “Castor” as a Canadian Word of the Day: https://web.archive.org/web/20110203042939/http://www.billcasselman.com/cwod_archive/beaver_castor_two.htm In his blog, Bill Casselman refers to a 1764 publication (Dissertation on the Oleum Palmae Christi) by Peter Canvane (The Huntington rare book holdings include the 1769 second edition).
Casselman relates a thought that herbal substitution of the plant oil for Beaver Castoreum led to the adoption of Castor Oil and Castor Bean as names for the product and the plant. That’s a fraught connection; one product does not substitute for the other.
But reading through the 1769 version of Canvane’s book, we are reminded of other associations. Ancient writers called the plant Ricinus because the seed have coloration that resembles the pattern of ticks. That became the name Linnaeus codified as the genus in his work. Another early name for Castor Bean was Agnus Castus (a common name also applied to Vitex). Canvane is the first to use the term Castor Oil in writing, reckoning the word ‘castus’ was corrupted to ‘castor’ by residents on the French settlement of St. Catherines, now called St. Kitts, where the plant was grown.
Why do we care about the confusion? Simple. This plant is everywhere; and it is potent. Ricinus communis (the proper scientific name for Castor Bean) is a handsome, tough, coarse, and weedy herb that can be found in edges and abandoned sites throughout Southern California, indeed, around the globe. We have nice stands of it in the Gardens, and we have grown it in the Herb Garden at The Huntington. You likely have seen it; you might be curious enough to dig or handle it some day.
But you should recognize and approach Ricinus with caution. Thought to be native to Africa, and perhaps even India, Ricinus has been known to Asian and Western cultures as a chemically-powerful plant for thousands of years. Over the long haul it has been used as a purgative, and at times employed for torture and murder. That being said, Castor Oil is still legally sold as a laxative today.
As was mentioned earlier, the seed from which oil is pressed are readily identified, having a handsome brown patterning early herbalists believed resembled the coloration pattern of ticks. This association is the source of its ancient name Ricinus, the Latin word for a tick. Along with other names, Kiki, Palma Christi, and Croton, we can find written history of this plant as Ricinus gallis Palma christi in L’Obel’s Plantarum seu stirpium historia (1576, p. 392), Ricinus vulgaris in Bauhin’s Pinax (1671, p 432 ), Ricinus africanus maximus in Tournefort’s Institutiones rei herbariae (1700, p. 542), settling finally with its current name, Ricinus communis, in Linnaeus’ Species Plantarum (1753.)
These names all seemed to exist before Canvane introduced the term Castor Oil for the useful and questionably salubrious fat pressed from the beautifully speckled Ricinus seed. In his treatise Canvane tells us how to extract oil from raw seed, products that are hazardous to handle because the seed are also the source of ricin, a very toxic natural chemical (a lectin).
As far as I am concerned, the raw seed and native oil are suspect until heat-treated to destroy traces of the lectin. And I take it further; neither castoreum nor castor oil will be on my shelf. I’m not interested in using fragrance extracted from anal glands of Beavers (castoreum). Even knowing that ricin is not expressed with the pressed oil (but must be extracted separately from the pulp) and a simple heat treatment eliminates any residual toxicity doesn’t placate me; I’ll not be using Castor Oil for salad dressing or cooking. Too much baggage. I’m happy enough just untangling the terminologies.
Almost…. I forgot to mention castor sugar. That’s just an alternative spelling for caster sugar. And the abnormal spelling…., Oyl? Well, Popeye’s femme faux fatale was Olive Oyl, whose older sibs were Crude Oyl and Castor Oyl…. I couldn’t let that cultural gem slip by.
*From Wikipedia: “Castoreum is largely used for its note suggesting leather, typically compounded with other ingredients including top, middle, and base notes. Some classic perfumes incorporating castor are Emeraude, Chanel Antaeus, Cuir de Russie, Magie Noire, Lancôme Caractère, Hechter Madame, Givenchy III, Shalimar, and many “leather” themed compositions.”