Poisonous plants
The Poison Chronicles: Bryony – Deadly Margins
Guest Post by Laura Cooper

The Hours of Jeanne de Navarre is one of the most famous and beautiful illuminated manuscripts. It is a collection of prayers and psalms for each of the hours of the medieval religious day made for the personal use of the Queen of Navarre somewhere between 1328-1343. The book is lavishly and elegantly decorated with images of saints and angels framed by a naturalistic border. This curling foliage has been referred to as ivy, but was identified by Christopher de Hamel actually white bryony, Bryonia dioica.
Bryony is a notoriously poisonous plant, so the scenes the illuminator painted are far from idyllic. As de Hamel writes in his book Meetings with Remarkable Manuscripts,“The world in the medieval margins is not a comfortable place, any more than the gilded life of Jeanne de Navarre was safe and secure.” Bryony is not just a decorative flourish, but a memento mori, a reminder of the danger that surrounded the medieval monarch.

In reality, despite it’s elabourate image, bryony is an unglamourous poisoner. The plant is the only gourd (family Cucurbitaceae) native to Britain, mostly found in Central and South Eastern England. Eating the plant produces powerful laxative effect, a scatological killer not fitting the intrigue of the royal court. There doesn’t seem to be any records of human poisoning by B. dioica, but it’s occurrence in hedgerows means livestock occasionally are poisoned by the root. Historical there would have been many more cases, however. B. dioica was used as a medicine, such as for leprosy, likely as a drug of last resort for an untreatable condition.

The B.dioica plant is remarkable for its large, rapidly-growing and foul-smelling root. Roots the size of one year old child were shown to John Gerard by the surgeon of Queen Elizabeth I, William Goderous.The size and speed at which the roots can grow means that they have been used by “knaves” to counterfeit the more alleged aphrodisiac mandrake (Mandragora officinarum). In his Universal Herbal of 1832, Thomas Green describes this practice; “The method which these knaves practiced was to open the earth round a young, thriving Bryony plant […] to fix a mould, such as is used by those who make plaster figures, close to the root, and then to fill in the earth about the root, leaving it to grow to the shape of the mould.” However, the notably effects of anticholinergic toxins of mandrake, inducing hallucinations and rapid heart rate, and the laxative bryony means these frauds were unlikely to have repeat customers.

The medieval margin illustrations feature identifiable bird species, but lack botanical detail. Bryonia dioica itself is a rapid climber of hedgerows. It’s five-lobed leaves have a rough feel with curling tendrils, white flowers and red berries which produce a foetid smelling juice when squeezed. The root is usually simple like a turnip and when cut produces a white foul smelling milk from the bitter succulent flesh.
Despite its surface charms, its scent, taste and effects are the exact opposite of belladona, meaning it lacks the glamour of this more famous poisoner.
The Poison Chronicles: Hemlock

Guest Post by Laura Cooper
Poison hemlock (Conium maculatum) is one of the most notorious of poisonous plants. It’s best known as the poison that killed the philosopher Socrates, and may even be indirectly responsible for the deaths of quail eaters, but even this species has been used as a medicine.

Conium maculatum is in the family Apiaceae. Many species in this family resemble hemlock as they possess white flowers in umbels, branches of the stem which form a flat surface, and pinnate leaves, resemble parsely (Petroselinum crispum) and wild carrot (Daucus carota). This has lead to foragers accidentally poisoning themselves, but most are put off by the “mousy” or foetid odour and bitter taste. This and red spots that appear on the base of the plant in spring, traditionally gained when the plant grew at the base of Christ’s cross, are key identification features. It is a common “weed” globally, and was introduced as an ornamental to North America.

A vivid account of hemlock poisoning is given in Plato’s Phaedo, where his teacher Socrates is sentenced to death by consuming a “poison” known to be C. maculatum. After being given the poison, Socrates “walked about until […] his legs began to fail, and then he lay on his back […] the man who gave him the poison […] pressed his foot hard, and asked him if he could feel; and he said, No; […] and so upwards and upwards, and showed us that he was cold and stiff. And he […] said: When the poison reaches the heart, that will be the end. […] in a minute or two […] his eyes were set, and Crito closed his eyes and mouth.” The execution is an apt one for a philosopher, as he retained conscience throughout. However, the description may be idealised to preserve the dignity of Plato’s old teacher, as most hemlock poisonings involve vomiting and seizures in addition to the creeping paralysis.

Hemlock kills by a cocktail of similar chemicals, including γ-coniceine and coniine. Coniine affecting the nicotinic receptors on neurons first to stimulate the nervous system, causing seizures, vomiting and tachycardia. Later it may inhibit the central nervous system, causing brachycardia and paralysis.

One of the most sinister ways of being poisoned by a plant is the rare condition coturnism. It is caused by eating quail, Coturnix coturnix, killed in the Mediterranean whilst migrating north from Africa in the spring (but not when returning in the autumn). It is widely reported that this is due to the quail consuming the seeds of C. maculatum, but there is conflicting evidence. According to E. F. Jelliffe, hemlock drops seed in late summer and autumn, meaning quail migrating north in the spring cannot have eaten this seed. Therefore, the cause of coturnism is still a mystery.

But despite it’s notoriety, C. maculatum features in medieval household remedies. It’s powers of sedation are utilized in a recipe for an anesthetic known as dwale. The recipe involves boiling pig bile, three spoonfuls each of of hemlock juice, opium and henbane, bryony, lettuce and vinegar and adding this to half a gallon of wine. Drinking this would apparently allow a person to fall asleep and be “safely cut”, after which vinegar and salt to the face would revive them. Though the mixture seems effective at knocking a person out, it is questionable that the vinegar would be enough to revive them. However, there is no scientific evidence that “root of hemlock, digged i’ th’ dark” that the witches in Macbeth add to their potion contributed to Macbeth’s false imperviousness.