How the Cure for Scurvy was Lost, then Found

Why the wrong theories can hold back progress

Some years ago, I stumbled across a post by a man named Maciej Ceglowski, where he told the story of how the world forgot the cure to a deadly disease.

Ceglowski was re-reading The Worst Journey in the World, the account of Robert Falcon Scott’s failed 1911 expedition to the South Pole. In retrospect, it is clear that Scott and his expedition were wracked with scurvy.

Scurvy was a common and deadly disease that was devastating on long sea voyages in centuries past. It is caused by a lack of vitamin C, because sailors weren’t eating any fresh greens or citrus fruits. The disease itself was grim - flaking skin, losing hair, bleeding gums. Old scars and wounds would break open, and it could be fatal.

When the cure was discovered - lemon or lime juice - it was close to being a miracle cure. Persons close to death could enjoy a near total recovery in days. Wounds would heal, bleeding would stop. Calling British sailors “limeys” was because of the limes they ate to stave off scurvy, especially in the 1800s.

Yet here, Ceglowski found that in the 1900s - after a century of scientific discoveries, the doctor on Scott’s trip seems to have no awareness that the cure to scurvy is Vitamin C, and he does not believe that limes will cure it.

Instead, the doctor favours,

“Almroth Wright’s theory that scurvy is due to an acid intoxication of the blood caused by bacteria… There was little scurvy in Nelson’s days; but the reason is not clear, since, according to modern research, lime-juice only helps to prevent it. We had, at Cape Evans, a salt of sodium to be used to alkalize the blood as an experiment, if necessity arose. Darkness, cold, and hard work are in Atkinson’s opinion important causes of scurvy.”

Ceglowski is puzzled. How can a 20th century naval physician not know that limes and lemons cure scurvy? Not only was it known, it was official British navy policy a century before. According to the history Ceglowski learned at school, the cure for scurvy had been discovered in 1747 by James Lind in one of “the first controlled medical experiments,” though it had taken years of further experimentation and lobbying to persuade the Navy to adopt it as policy.

The timeline is that:

• In 1747, a scientific discovery based in experiment and evidence takes place.

• About 50 years later, by 1799, it is official policy and eradicates a deadly disease.

• By 1911, it has been completely forgotten.

What happened in the meantime?

It is a story of unique biology, historical accident, politics and changes in technology - but also a lesson in the way we think. Sometimes, we will reject evidence if it doesn’t fit a theory.

In the early 1800s, the British Navy knew that lemons cured scurvy. Tests had proved it - but there was no theory to explain why or how it worked. The fact that it worked was proof enough.

Technology changed. Sailing ships were replaced with coal-fired steamships, which travelled much more quickly. Journeys that used to take months took days or weeks, so sailors weren’t at sea long enough to succumb to scurvy. Citrus juice was legally required on all British ships until 1867, then was phased out because it wasn’t being used.

The way we understand diseases also changed. Louis Pasteur popularized the germ theory of disease. It was incredibly effective in explaining and addressing illness, whether it was rabies, illness carried in milk, or disease affecting silkworms. Bacteria could be seen under a microscope - there was clear evidence for it. Scurvy is not caused by the presence of bacteria - it is caused by the absence of vitamin C, but no one knew what vitamin C was.

It was assumed, therefore, that scurvy was caused by an infection. It was obvious that lemons and limes were acidic - so there was speculation that people’s bodies needed more acid.

A third change was economic. In 1860, the Navy had begun to switch from lemons to limes, in part for economic reasons. Lemons had to be imported from foreign nations at higher expense, while limes were grown in the West Indies, which were part of the British Empire. While British sailors were called “limeys,” the terms limes and lemons could be used interchangeably. They are not.

Lemons have four times the vitamin C as limes - limes are only a quarter as effective. The lime juice on board ship was also exposed to open air and run through copper pipes, a process that further depleted the vitamin C.

By the late 1800s, the only voyages where people were at sea long enough to develop scurvy were arctic expeditions.

The “cure” of lime juice no longer worked, so a new theory for what caused scurvy was developed, based in the science of the day. The scurvy of arctic expeditions in 1875 and 1894 was thought to be caused by “ptomaine poisoning” - “a kind of chronic food poisoning from bacterial contamination of meat.”

This was the theory of scurvy that Scott took with him to the Antarctic.

Ceglowski writes:

“Entire academic careers have been devoted to second-guessing Scott's final journey. It would probably be easier to list the few things that didn’t contribute to his death, than to try and rank the relative contributions of cold, exhaustion, malnutrition, bad weather, bad luck, poor planning, and rash decisions. But with regard to scurvy, at least, the Polar explorers were in an impossible position.

They had a theory of the disease that made sense, fit the evidence, but was utterly wrong. They had arrived at the idea of an undetectable substance in their food, present in trace quantities, with a direct causative relationship to scurvy, but they thought of it in terms of a poison to avoid. In one sense, the additional leap required for a correct understanding was very small. In another sense, it would have required a kind of Copernican revolution in their thinking.

It was pure luck that led to the actual discovery of vitamin C. Axel Holst and Theodor Frolich had been studying beriberi (another deficiency disease) in pigeons, and when they decided to switch to a mammal model, they serendipitously chose guinea pigs, the one animal besides human beings and monkeys that requires vitamin C in its diet. Fed a diet of pure grain, the animals showed no signs of beriberi, but quickly sickened and died of something that closely resembled human scurvy.

No one had seen scurvy in animals before. With a simple animal model for the disease in hand, it became a matter of running the correct experiments, and it was quickly established that scurvy was a deficiency disease after all. Very quickly the compound that prevents the disease was identified as a small molecule present in cabbage, lemon juice, and many other foods, and in 1932 Szent-Györgyi definitively isolated ascorbic acid.”

The story of how we forgot is important. A known, potent and effective cure for scurvy was abandoned in favour of treatments that didn’t work, because people did not understand how it could work. Not only was there no accurate theory for why scurvy was happening - the theories they did have discouraged people from embracing the cure.

Not all innovations and theories are correct or beneficial: there are dead-ends, mistakes, false positives, and missing negatives. We may have been right the first time, and the switch to something else was a mistake. Complicated, unsatisfying but correct may be replaced by ideas that are simple, satisfying and wrong.

There is a deeper lesson - about how we think the way the world works, and how we make mistakes. The British Navy depended on lemons to cure and treat scurvy, and it helped them conquer the world. Because the cure didn’t fit into an accepted explanation, it was forgotten and rejected. Instead, an imaginary disease was invented to explain the problem. People died as a result.

After I first read this story, it nagged at me. The idea that a simple cure could be lost - and that people could die miserably as consequence - not because of a lack of evidence, but because of a lack of the right theory to justify and recognize something that years of practice had shown works.

In fact, the “cure” for scurvy has been lost and found over the centuries. It tells us a lot about our assumptions of progress. Not all new ideas, theories or world views work. We can lose useful knowledge. We can go backwards, and find ourselves further behind.

Learning the right lessons has always been the challenge of all human knowledge, and especially of scientific endeavour. We can defy reason, and gravity, but only for so long. As was once said “you can drive nature out with a pitchfork - it always comes back in.”