Where does that come from? A regular column that examines the history and origins of a particular medical topic.

That well-known soldier, pirate, courtier, poet and general layabout, Sir Walter Raleigh, is generally regarded as being first to introduce the potato and tobacco into the Western world. Despite this dubious initiative, his life was brought to an abrupt end on the scaffold in 1618, but not, however, before his active curiosity had led him to publish a thesis which, while little remembered now, was to eventually set off a chain reaction in medical circles hardly less cosmic than the lung cancer his earlier discovery was to occasion. In 1595 he wrote about the physical effects in humans of the poisoned arrows of the South American Indians and it is the refined derivatives of this very poison which are used as muscle relaxants in anaesthetics today, and which have made modern surgery, including cosmetic surgery, possible.

What reminded me of this was the death in January 2008 of Professor T Cecil Gray at the age of 95. He not only used to teach me anaesthetics in Liverpool, but was one of the men who introduced this muscle relaxant to medicine in the 1940s.

But back to Raleigh who wrote of ‘a most ugly and lamentable death', of paralysis and of ‘bowels breaking out of their bellies' if on the receiving end of one of the curare-tipped arrows. The potion's secret was passed from father to son and, he went on, ‘all that could be ascertained either by gift or torment' was that it was made from the juice of a root called tupara. The odd thing was, he noted, that if taken orally this same fluid was not only non-toxic, but also ‘quenched marvellously the heat of burning fever, and healed inward wounds and broken veins'.

There the matter rested for 317 years until an eccentric Yorkshireman, Charles Waterton, who, in going to South America to collect specimens of these long-forgotten poisons, stepped from the obscurity of his squirearchy at Walton Hall, Wakefield, into that of the footnotes of the weightier tomes on anaesthetics.

One of Waterton's little eccentricities was that he bled himself frequently and profusely for his health's sake and wore clothes of such a tattered and verminous nature that he was usually shown to the servants hall when visiting his neighbours. All of this makes him sound to be just the man to go and paddle up the Amazon and track down Raleigh's legendary poison.

His first voyage in 1812 to Demerara was famous for nothing more lethal than the eponymous sugar. He located the suspected source of the poison, the wourali vine, and found the strongest brew was concocted by the Macoushi tribe. The arrows were made with detachable tips in protective caps for carrying. When shot, a sloth died within 10 minutes and an ox in 25.

Although the main constituent was from the vine, other additives in the formula were the juice of two unnamed bulbous plants and a bitter root and two species of crushed ant. Indian pepper and the powdered fangs of the Labarri and Counacouchi snakes were added, muttered over and boiled for two days then put in a pot and dried. No women could watch the manufacture and a new pot was used each time.

While Squire Waterton brought some of the confection back to England and tried it on various animals, did not immediately stumble on a clinical use for the brew. He had been told that a person rendered unconscious by the poison (but not dead) could be revived with the aid of bellows, provided inflation was carried on for long enough. With this in mind, Waterton proceeded to experiment. As he put it, ‘a she-ass received wourali poison in the shoulder, and apparently died in 10 minutes. An incision was made into the windpipe, and through it the lungs were regularly inflated for two hours with a pair of bellows. Suspended animation returned... but on stopping inflation she sunk once more into apparent death.' Artificial respiration was resumed, and the animal recovered completely. The ass, tweely renamed Wourali, was put out to pasture for the rest of her days and is still spoken of fondly wherever anaesthetists gather.

The intrepid Yorkshireman had inadvertently stumbled on the muscle relaxing properties of the drug as distinct from its fatal effect. Regrettably, this aspect was not recognised until long after our hero had died in 1865, hence his presence in the footnotes of medical books rather than the text itself.

In 1841 Robert Schomburg looked into the pharmacology of the poison, concluding that all those gobbets of snake and ants were surplus to requirement, and the active ingredient was the juice from the plant Strychnos toxifera. Curare, the name we now use for the drug, comes from the Macoushi name urari.

During the 1930s when it was being studied, the raw material from Guyana was so crude that it was named according to the vessel in which it arrived, so there was gourd, calabash, pot and tube curare. The latter was a shiny black resinoid mass, and it was from this variety that the crystalline extract d-Tubocurare was obtained.

Schomburg also noted that if wounded by an arrow tipped with poison, the ensuing thirst was almost intolerable. Even more odd was the fact that death certainly followed if the thirst was quenched with water. Raleigh had made the same observation and that once it had been made, the brew's potency was retained.

Initially curare was used in the West as a treatment for tetanus, and in 1942 given for the first time as a muscle relaxant during an anaesthetic by Dr Harold Griffith of Montreal. At the end of World War II it was in such short supply that if an anaesthetist had a bottle, he jealously guarded his supply by carrying it about in his waistcoat pocket.

Curare has generally been succeeded as a muscle relaxant by more refined synthetic products, but it is still obtainable. It provides a unique direct link between ancient and timeless jungle science and flashy modern technology.

ACSM #40