Elizabethan. Curare: A new and curious poison

The villain in The Widows Guild uses an exotic poison to subdue and kill the victims. Tom notices curareimprints on the bed on either side of the victim, suggesting someone knelt over the body. The murderer also carved a cross on the victim’s chest, leaving a dark, tarry residue on the edges of the wound. No other cause of death can be discerned. There are no signs of vomiting and only evidence of a brief struggle.

These clues cause Francis Bacon to suspect a poison that kills swiftly, entering the body through a wound in the skin, and that causes paralysis. He visits his favorite apothecary to discuss the possibilities. Nothing in their experience fits the facts. Other elements in the case suggest a Spanish connection, which suggests a new type of poison, brought from the New World.

The facts, Madame

Curare causes weakness of the skeletal muscles and, when administered in a sufficient dose, eventual death by asphyxiation due to paralysis of the diaphragm.

The illustration here is of Strychnos toxifera, but curare – an alkaloid arrow poison – can be made from many plants. In the Amazon there is such a bounty of plants so rich in alkaloids that an effective curare can be made by boiling down several kilos of any combination of 20 different species of jungle leaves. Once it becomes a thick syrupy tar it will most likely be able to bring down anything from a monkey to a man.

The Huaorani tribe’s method of preparation is to combine young bark of “curare-vine” with crushed roots and stems, and mix them with snake venom. The mixture is boiled in water for about 48 hours, then strained and evaporated to become a dark, heavy, viscid paste. Potency is tested by counting the number of leaps a frog takes after being pricked with the substance. Tribe members tip darts with curare and fire through blowguns made of iron tree. Death for mammals like tapirs and monkeys takes up to 20 minutes. I figured a man is 3-4 times the size of an Amazonian monkey, so an hour or more for death.

Curare has no effect if ingested so the meat of an animal killed by curare does not become poisonous, and it has no effect on its flavor.

The flying death

Tales of the mysterious ‘flying death’ were brought home to the Old World by Spanish conquistadors. Peter Martyr d’Anghera, a chronicler in the Court of King Ferdinand and Queen Isabella, first wrote of the poisoned arrows in his book De Orbe Novo, a collection of letters written in 1516. This was a blend of fact and fantasy that contributed to the mystique of curare and drew many men in its quest, some to their deaths.

In 1594, Sir Walter Raleigh visited Venezuela, and his book Discovery of the Large, Rich and Beautiful Empire of Guiana mentions the poisoned arrows. One of his lieutenants called the poison ‘ourari.’

Apply the anaesthetic

Jump ahead to the wonderful nineteenth century. In 1804 Charles Waterton, an eccentric explorer, left the family seat Walton Hall in Yorkshire to manage the sugar estates owned by his family in Demerara, South America. He obtained several samples of wourali from a native tribe and tried it out on large animals.

During 1811–1812 Sir Benjamin Collins Brody showed that curare does not kill an animal and the recovery is complete if the animal’s respiration is maintained artificially. This suggested that curare might be useful as an anaesthetic.

Claude Bernard published the details of his experiments on frogs in 1846. He showed that curare injected into a limb prevented the muscle contraction in response to nerve stimulation; the muscle continued to respond when stimulated directly.

In 1946 Frederick Prescott found himself on a table, unable to move. He was completely paralyzed. Two minutes prior he was intravenously injected with 30 mg of d-tubocurarine, and now he was in trouble. He could not open his eyes, speak, or even swallow, and no one in the room was aware of his distress. Another minute ticked by, and his breathing became rapid and shallow.  Another minute, and he was terrified. He gasped for breath as his airway filled with mucus. Just as he lost consciousness, his colleagues started artificial respiration and manual compression. It took seven minutes for him to start breathing on his own, and another thirty to regain use of his body. Six hours later, he was right as rain, save for tightness in his chest that persisted for several days.

You have to love those Victorian scientists. “Hm,” thought Frederick Prescott. “What do you suppose this stuff really feels like?” Then he injects himself without further ado; fortunately, in the presence of his quick-witted colleagues.

Sources

Rhagavendra, Thankdla. 2002. “Neuromuscular blocking drugs: Discovery and development,” Journal of the Royal Society of Medicine, 2002 Jul; 95(7): 363–367.

Wikipedia: Curare

Tropical Plant Database: Curare

 

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