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How Randomised Trials won the Battle of Trafalgar in 1805

Listening to Karl Kruszelnicki’s Shirtloads of Science podcast episode on June 24, 2018 – titled Randomistas – they’ve won wars, healed the sick and helped us learn revealed an interesting example, in Admiral Nelson at the Battle of Trafalgar, as to the value of randomised trials in shaping the World. The interviewee was Andrew Leigh, author of Randomistas: How Radical Researchers Changed Our World.

To set the scene, Andrew Leigh points out that in the Seven Years’ War (1756-1763) scurvy caused the vast majority of deaths. A huge 180,000 men died in the British Navy in those seven years and a less impressive couple of thousand were killed in the fighting. Scurvy was that bad.

So what is scurvy? Richard Walter, a chaplain on a 1740s voyage into the Pacific described the symptoms of scurvy as:

skin black as ink, ulcers, difficult respiration, rictus of the limbs, teeth falling out and, perhaps most revolting of all, a strange plethora of gum tissue sprouting out of the mouth, which immediately rotted and lent the victim’s breath an abominable odour.

Britain, however, was fortunate enough to have a surgeon’s mate named James Lind (1716-1794) who decided in 1748 to run a two-week controlled randomised trial on twelve men. It was known that lemon juice cured scurvy, but the medical wisdom of the day dictated it as a problem of the humours (that horseshit about body fluids – blood, yellow bile, black bile and phlegm).

James Lind gave six proposed cures to the twelve men in pairs – cider, vitriol, vinegar, sea water, oranges and lemons, and nutmeg paste. Oranges and lemons proved to be the most effective in the randomised trial.

Andrew Leigh points to Lind’s randomised trial and Nelson’s position (nearly sixty years later) before the Battle of Trafalgar in 1805. Admiral Nelson, who had endured scurvy and survived in 1780, approached a larger force of Spanish and French ships off Cape Trafalgar, Spain, on 21 October, 1805. Nelson had at his disposal a Royal Navy regularly ingesting lemon juice (and therefore scurvy free and fighting healthy). Whereas, the Spanish and French navies had no such luxury among their crews.

At the Battle of Trafalgar, Nelson lost 458 dead with a total cost including casualties of 1,666 men. France and Spain suffered a combined 13,781 men killed, wounded and captured. Approximately three thousand prisoners of war drowned in a storm after the battle.

So, Leigh says, where we are taught in history to attribute Nelson’s direct attack tactics as winning the Battle of Trafalgar in 1805, Nelson’s victory was due in great part to the healthiness of the Royal Navy. And, Leigh says, we could well be speaking French or Spanish had the battle gone badly for the British.

To be fair, James Lind (1716-1794), Captain James Cook (1728-1779) and a physician named Gilbert Blane (1749-1843) share the praise for bringing an end to scurvy at sea. James Lind identified the cure, but he didn’t understand the cause as a lack of Vitamin C (ascorbic acid). However, Lind’s story illustrates the value of controlled randomised trials in our society and the benefits that accrue from proper scientific study (as opposed to, say, homeopathic or belief-based cures) to solve large real world problems. Let’s tip our hat to Science.

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Steven Clark Steven Clark - the stand up guy on this site

My name is Steven Clark and I live in the Derwent Valley in Southern Tasmania. I have an MBA (Specialisation) and a Bachelor of Computing from the University of Tasmania. I'm a mazer & a yeast farmer (making beer, fruit wine and mead as by-products of continuous improvement in my farming practices). I'm a photographer, although my film cameras are currently silent. I do not tolerate idiots. I do not tolerate bigotry. I do not tolerate excuses. Let's be clear, if you sit with my enemies you my are my enemy for life.

Blogger. Thinker. Brewer. Drinker. Life partner to the amazing and incredible Megan.

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