I was looking at the delightfully spiky fruit of a castor bean plant recently, and speaking to the horticulturist, Charles Cody, who grows them where I work at Washington State University.
Castor bean plants are an impressive annual, meaning that if you plant them in full sun and good soil, they’ll go from little beans in the spring to plants about 6 to 8 feet tall before the first frost of the fall. In warmer places, they can become even larger with leaves two or three feet across.
Some gardeners grow castor bean plants simply for their dramatic height, or because of the shade they can produce for other plants. Other gardeners value the plant’s natural abilities to repel insect pests.
But most castor bean plants in the world are grown commercially for the sake of the castor oil we make from the beans. Castor oil is used in everything from brake fluid (I kid you not) to the old fashioned laxatives in which Grandpa believed. That’s quite a flexible product. And it gets even better.
As you know, “oil and water don’t mix.” If you pour olive oil into a pot of water in your kitchen, it just floats to the top.
But when sulfuric acid is mixed with castor oil, the result is a Turkey Red Oil – named for the historic dye-color called “turkey red.” Oil of that name has the unusual distinction of dispersing into water rather than floating to the top of it. So Turkey Red Oils mix with water, and that’s vital to detergents, shampoo, and bath oils.
The only trouble with growing oodles of castor bean plants to make Turkey Red Oil for humanity’s needs is that part of the bean contains ricin. Ricin is a highly toxic poison. It can make field workers in developing countries ill due to chronic exposure where lots of castor beans are grown. And here in the First World, ricin is a favorite of the more sophisticated sort of angry ex-husband because a very tiny amount of pure ricin is enough to kill a person.
The most famous ricin-poisoning incident is one that sticks in my mind because it concerned a writer. Some years ago during the Cold War, Georgi Markov was a Bulgarian journalist living in London and working for the BBC. He had been well known in his native Bulgaria, and when he defected to the West, his choice embarrassed his former masters.
One evening in London, as Markov waited for a bus on the sidewalk, he felt a sting in his leg. A man had poked him with an umbrella tip. The man apologized and ducked into a nearby taxi.
Markov fell ill. He rapidly worsened. But he lived long enough to voice his suspicions about the incident on the sidewalk to Scotland Yard. Another Bulgarian defector then told the authorities of a similar event he’d experienced on the streets of Paris. He had been quite ill after his experience, but survived, while Markov died.
Both Markov’s corpse and the Bulgarian who had lived were shown to have tiny metal pellets in them where they had received their puncture wounds. The pellets had holes in them – likely filled with ricin poison when they entered their bodies.
Ricin is obviously quite a powerful chemical. That’s why if a child or Fido eats the good-looking castor beans in a backyard garden, death can result.
The good news is that scientists are researching ways to bioengineer castor beans plants that simply would not infuse their valuable oil with ricin. This kind of research is part of the on-going “biotech” revolution that, in this case, could mean a less toxic cash crop for farmers, less illness for field workers in the developing world who deal with the beans all the time, and safer ornamental plants in the backyard. It’s part of the realm of GMO (Genetically Modified Organisms) which some people fear but others welcome due to its many practical benefits.
Most people agree that ricin-free castor beans will be a clear step up for everyone except Miss Marple and field workers in poor areas of the world. And I expect they will come about in your lifetime because of science’s increasing ability to manipulate the genetic code of life.