[wordup] How we lost the cure to scurvy

[Adam Shand]

This is old, but for everybody who missed it (like me), it's also a
fascinating account of how we totally botched figuring out what cured scurvy
... ever though we already knew, and had used, the correct answer for a
couple hundred years.

I very much like the reminder that the author leaves us with at the end of
the article:

Finally, that one of the simplest of diseases managed to utterly confound us
> for so long, at the cost of millions of lives, even after we had stumbled
> across an unequivocal cure. It makes you wonder how many incurable ailments
> of the modern world - depression, autism, hypertension, obesity - will turn
> out to have equally simple solutions, once we are able to see them in the
> correct light. What will we be slapping our foreheads about sixty years from
> now, wondering how we missed something so obvious?


It's important for us all to remember, that we can do much harm in the name
of science.  Invoking "science" doesn't in any way reduce the damage of
being wrong.

Adam.

Source: http://idlewords.com/2010/03/scott_and_scurvy.htm

03.07.2010
Scott and Scurvy

Recently I have been re-reading one of my favorite books, The Worst Journey
in the World, an account of Robert Falcon Scott's 1911 expedition to the
South Pole. I can’t do the book justice in a summary, other than recommend
that you drop everything and read it, but there is one detail that
particularly baffled me the first time through, and that I resolved to
understand better once I could stand to put the book down long enough.

Writing about the first winter the men spent on the ice, Cherry-Garrard
casually mentions an astonishing lecture on scurvy by one of the
expedition’s doctors:

Atkinson inclined to 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.

Now, I had been taught in school that scurvy had been conquered in 1747,
> when the Scottish physician James Lind proved in one of the first controlled
> medical experiments that citrus fruits were an effective cure for the
> disease. From that point on, we were told, the Royal Navy had required a
> daily dose of lime juice to be mixed in with sailors’ grog, and scurvy
> ceased to be a problem on long ocean voyages.


But here was a Royal Navy surgeon in 1911 apparently ignorant of what caused
the disease, or how to cure it. Somehow a highly-trained group of scientists
at the start of the 20th century knew less about scurvy than the average sea
captain in Napoleonic times. Scott left a base abundantly stocked with fresh
meat, fruits, apples, and lime juice, and headed out on the ice for five
months with no protection against scurvy, all the while confident he was not
at risk. What happened?

...

By all accounts scurvy is a horrible disease. Scott, who has reason to know,
gives a succinct description:

The symptoms of scurvy do not necessarily occur in a regular order, but
> generally the first sign is an inflamed, swollen condition of the gums. The
> whitish pink tinge next the teeth is replaced by an angry red; as the
> disease gains ground the gums become more spongy and turn to a purplish
> colour, the teeth become loose and the gums sore. Spots appear on the legs,
> and pain is felt in old wounds and bruises; later, from a slight oedema, the
> legs, and then the arms, swell to a great size and become blackened behind
> the joints. After this the patient is soon incapacitated, and the last
> horrible stages of the disease set in, from which death is a merciful
> release.


One of the most striking features of the disease is the disproportion
between its severity and the simplicity of the cure. Today we know that
scurvy is due solely to a deficiency in vitamin C, a compound essential to
metabolism that the human body must obtain from food. Scurvy is rapidly and
completely cured by restoring vitamin C into the diet.

Except for the nature of vitamin C, eighteenth century physicians knew this
too. But in the second half of the nineteenth century, the cure for scurvy
was lost. The story of how this happened is a striking demonstration of the
problem of induction, and how progress in one field of study can lead to
unintended steps backward in another.

An unfortunate series of accidents conspired with advances in technology to
discredit the cure for scurvy. What had been a simple dietary deficiency
became a subtle and unpredictable disease that could strike without warning.
Over the course of fifty years, scurvy would return to torment not just
Polar explorers, but thousands of infants born into wealthy European and
American homes. And it would only be through blind luck that the actual
cause of scurvy would be rediscovered, and vitamin C finally isolated, in
1932.

It is not easy to find fresh foods that lack vitamin C. Plants and animals
tend to be full of it, since the molecule is used in all kinds of
biochemical synthesis as an electron donor. But the same reactive qualities
that make the vitamin useful also make it easy to destroy. Vitamin C quickly
breaks down in the presence of light, heat and air. For this reason it is
absent from most preserved foods that have been cooked or dried. Its
destruction is also rapidly catalyzed by copper ions, which may be one
reason sailors, with their big copper cooking vats, were particularly
susceptible.

Because our bodies can't synthesize the vitamin, they have grown very good
at conserving it. It takes up to six months for scurvy to develop in healthy
people after vitamin C is removed from the diet, and only a tiny daily
amount is enough to keep a person healthy.

It has been known since antiquity that fresh foods in general, and lemons
and oranges in particular, will cure scurvy. Starting with Vasco de Gama’s
crew in 1497, sailors have repeatedly discovered the curative power of
citrus fruits, and the cure has just as frequently been forgotten or ignored
by subsequent explorers.

Lind tends to get the credit for discovering the citrus cure since he
performed something approaching a controlled experiment. But it took an
additional forty years of experiments, analysis, and political lobbying for
his result to become institutionalized in the Royal Navy. In 1799, all Royal
Navy ships on foreign service were ordered to serve lemon juice:

The scheduled allowance for the sailors in the Navy was fixed at I oz.lemon
> juice with I + oz. sugar, served daily after 2 weeks at sea, the lemon juice
> being often called ‘lime juice’ and our sailors ‘lime juicers’. The
> consequences of this new regulation were startling and by the beginning of
> the nineteenth century scurvy may be said to have vanished from the British
> navy. In 1780, the admissions of scurvy cases to the Naval Hospital at
> Haslar were 1457; in the years from 1806 to 1810, they were two.


(As we'll see, the confusion between lemons and limes would have serious
reprecussions.)

Scurvy had been the leading killer of sailors on long ocean voyages; some
ships experienced losses as high as 90% of their men. With the introduction
of lemon juice, the British suddenly held a massive strategic advantage over
their rivals, one they put to good use in the Napoleonic wars. British ships
could now stay out on blockade duty for two years at a time, strangling
French ports even as the merchantmen who ferried citrus to the blockading
ships continued to die of scurvy, prohibited from touching the curative
themselves.

The success of lemon juice was so total that much of Sicily was soon
transformed into a lemon orchard for the British fleet. Scurvy continued to
be a vexing problem in other navies, who were slow to adopt citrus as a
cure, as well as in the Merchant Marine, but for the Royal Navy it had
become a disease of the past.

By the middle of the 19th century, however, advances in technology were
reducing the need for any kind of scurvy preventative. Steam power had
shortened travel times considerably from the age of sail, so that it was
rare for sailors other than whalers to be months at sea without fresh food.
Citrus juice was a legal requirement on all British vessels by 1867, but in
practical terms it was becoming superfluous.

So when the Admiralty began to replace lemon juice with an ineffective
substitute in 1860, it took a long time for anyone to notice. In that year,
naval authorities switched procurement from Mediterranean lemons to West
Indian limes. The motives for this were mainly colonial - it was better to
buy from British plantations than to continue importing lemons from Europe.
Confusion in naming didn't help matters. Both "lemon" and "lime" were in use
as a collective term for citrus, and though European lemons and sour limes
are quite different fruits, their Latin names (citrus medica, var. limonica
and citrus medica, var. acida) suggested that they were as closely related
as green and red apples. Moreover, as there was a widespread belief that the
antiscorbutic properties of lemons were due to their acidity, it made sense
that the more acidic Caribbean limes would be even better at fighting the
disease.

In this, the Navy was deceived. Tests on animals would later show that fresh
lime juice has a quarter of the scurvy-fighting power of fresh lemon juice.
And the lime juice being served to sailors was not fresh, but had spent long
periods of time in settling tanks open to the air, and had been pumped
through copper tubing. A 1918 animal experiment using representative samples
of lime juice from the navy and merchant marine showed that the
'preventative' often lacked any antiscorbutic power at all.

By the 1870s, therefore, most British ships were sailing without protection
against scurvy. Only speed and improved nutrition on land were preventing
sailors from getting sick.

It fell to the unfortunate George Nares to discover this fact in 1875, when
he led the British Arctic Expedition in an attempt to reach the North Pole
via Greenland. Some oceanographic theories of the time posited an open polar
sea, and Nares was directed to sail along the Greenland coast, then take a
sledging party and see how far north he could get on the pack ice.

The expedition was a fiasco. Two men in the sledging party developed scurvy
within days of leaving the ship. Within five weeks, half the men were sick,
and despite having laid depots with plentiful supplies for their return
journey, they were barely able to make it back. A rescue party sent to
intercept them found that lime juice failed to have its usual dramatic
effect. Most damning of all, some of the men who stayed on the ship, never
failing to take their daily dose, also got scurvy.

The failure of the Nares expedition provoked an uproar in Britain. The Royal
Navy believed itself capable of sustaining any crew for two years without
signs of scurvy, yet here was an able and adequately supplied crew crippled
by the disease within weeks. For the first time since the eighteenth
century, the effectiveness of citrus juice as an absolute preventative was
in doubt.

More troubling evidence came several years later, during the
Jackson-Harmsworth Expedition to Franz-Josef Land in 1894. Members of this
expedition spent three years on a ship frozen into the pack ice. Koettlitz,
their chief physician, describes what happened:

The expedition proper ate fresh meat regularly at least once a day in the
> shape of polar bear. The people on the ship had, however, a prejudice
> against this food, which certainly was not particularly palatable, and
> insisted, against all advice, upon eating their preserved and salted meat.
> This meat I occasionally noticed to be somewhat "high" or "gamey", and
> afterwards heard that it was often so. The result was that, though I visited
> the ship every day, and personally saw that each man swallowed his dose of
> lime juice (which was made compulsory, and was of the best quality), the
> whole ship’s company were tainted with scurvy, and two died.


This pattern of fresh meat preventing scurvy would be a consistent one in
Arctic exploration. It defied the common understanding of scurvy as a
deficiency in vegetable matter. Somehow men could live for years on a
meat-only diet and remain healthy, provided that the meat was fresh.

This is a good example of how the very ubiquity of vitamin C made it hard to
identify. Though scurvy was always associated with a lack of greens, fresh
meat contains adequate amounts of vitamin C, with particularly high
concentrations in the organ meats that explorers considered a delicacy. Eat
a bear liver every few weeks and scurvy will be the least of your problems.

But unless you already understand and believe in the vitamin model of
nutrition, the notion of a trace substance that exists both in fresh limes
and bear kidneys, but is absent from a cask of lime juice because you
happened to prepare it in a copper vessel, begins to sound pretty contrived.

Doctors of the era looked at this puzzling evidence and wondered. Other
diseases had recently been shown to have their source in bacterial
infection. The bacterial model was new, and had already had spectacular
success in identifying and treating diseases like typhus, tuberculosis, and
cholera. What if the cause of scruvy had also been misunderstood? What if
instead of a deficiency disease, scurvy was actually a kind of chronic food
poisoning from bacterial contamination of meat? Thus was born the ptomaine
theory of scurvy, and Koettlitz became its enthusiastic backer:

That the cause of the outbreak of scurvy in so many Polar expeditions has
> always been that something was radically wrong with the preserved meats,
> whether tinned or salted, is practically certain; that foods are
> scurvy-producing by being, if only slightly, tainted is practically certain;
> that the benefit of the so-called "antiscorbutics" is a delusion, and that
> some antiscorbutic property has been removed from foods in the process of
> preservation is also a delusion. An animal food is either scorbutic - in
> other words, scurvy-producing - or it is not. It is either tainted or it is
> sound. Putrefactive change, if only slight and tasteless, has taken place or
> it has not. Bacteria have been able to produce ptomaines in it or they have
> not; and if they have not, then the food is healthy and not
> scurvy-producing.


The ’ptomaine’ in the theory was never really defined, other than as a
noxious waste product of bacterial action. But the theory had an internal
logic. Poorly preserved meats would be contaminated by ptomaine. Under
normal conditions, this was not enough cause scurvy. Not only did fresh food
consumed in the diet have a kind of antidote effect (whether it worked by
neutralizing the poison, or by simply displacing it in the diet, was not
clear), but environment also played an important role. Certain factors
seemed to predispose people to chronic ptomaine poisoning, including
darkness, intense exertion, idleness, close air, prolonged confinement and
cold.

On prolonged journeys under harsh conditions, the accumulated ptomaine in
badly preserved meats would disrupt health, giving the classic symptoms of
scurvy. Once the tainted foods were discontinued, the body would rapidly
excrete the accumulated ptomaine and return to healthh.

To the extent that citrus juices were effective in preventing scurvy, it was
because their acidity denatured ptomaines, or killed the bacteria that
caused them. The real culprit was in the bad meat, and the casks of lime
juice mandated by law on every seagoing ship were another example of
outdated medical superstition that would now give way to a more
sophisticated understanding of illness.

This was the latest in medical thinking on scurvy when Scott prepared for
his first expedition to Antarctica, in 1903. It would be the first serious
British expedition to the continent in fifty years. Scott took the very same
Dr. Koettlitz along as his chief physician.

Scott was a meticulous planner, and mindful of the ptomaine theory, paid
special attention to the quality of his provisions. While the cold and
cramped conditions of the journey could not be helped, he knew he could
avoid any risk of scurvy by using only completely unspoiled canned goods.
For his part, Koettlitz predicted that as long as there was fresh seal meat
available, "we can take it as certain that no scurvy will be heard of in
connexion with the expedition, however long it may remain in the High
South".

Scott did not have time to supervise the actual canning of his provisions
for the Discovery journey, but he made sure that before being served, all
tins were opened in the presence of his medical staff, including Dr.
Koettlitz, and carefully examined for signs of spoilage. Any doubtful cans
were consigned to the trash heap.

So it came as a bitter surprise to Scott when one of the Discovery’s early
sledging parties trudged into camp with unmistakable symptoms of scurvy
after only a three week absence. Subsequent examination showed that many of
the men on the ship were also in the early stages of the disease. The
preventative measures had failed, and Scott was greatly distressed:

The evil having come, the great thing now is to banish it. In my absence,
> Armitage, in consultation with the doctors, has already taken steps to
> remedy matters by serving out fresh meat regularly and by increasing the
> allowance of bottled fruits, and he has done an even greater service by
> taking the cook in hand. I don’t know whether he threatened to hang him at
> the yardarm or used more persuasive measures, but, whatever it was, there is
> a marked improvement in the cooking.

...

With the idea of giving everyone on the mess-deck a change of air in turn,
> we have built up a space in the main hut by packing cases around the stove.
> In this space each mess are to live for a week; they have breakfast and
> dinner on board, but are allowed to cook their supper in the hut. The
> present occupants enjoy this sort of picnic-life immensely.


> We have had a thorough clearance of the holds, disinfected the bilges,
> whitewashed the sides, and generally made them sweet and clean.


> As a next step I tackled the clothes and hammocks. One knows how easily
> garments collect, and especially under such conditions as ours; however,
> they have all been cleared out now, except those actually in use. The
> hammocks and bedding I found quite dry and comfortable, but we have had them
> all thoroughly aired. We have cleared all the deck-lights so as to get more
> daylight below, and we have scrubbed the decks and cleaned out all the holes
> and corners until everything is as clean as a new pin. I am bound to confess
> there was no very radical change in all this; we found very little dirt, and
> our outbreak cannot possibly have come from insanitary conditions of living;
> our men are far too much alive to their own comfort for that. But now we do
> everything for the safe side, and from the conviction that one cannot be too
> careful.


Scott sent a seal-killing party to collect as much fresh meat as possible
(his crew could eat their way through a seal in two and a half days). They
gathered enough to eliminate the need for preserved meat entirely. The
butchered seals were stored, like logs, frozen on the ice. Meanwhile,
Koetlittz had managed to sprout and grow a modest crop of watercress under a
skylight, the Antarctic soil proving surprisingly fertile. His confidence in
the ptomaine theory did not blind him to the practical advantages of a
proven remedy (watercress sprouts contain a ridiculous amount of vitamin C).
Enough cress grew to supplement one meal for all the men, and in combination
with the fresh seal meat, it was enough to banish all signs of scurvy.

Scott was relieved, but he knew that something had escaped his
understanding. Despite scrupulous care, the disease had slipped through, and
he was not sure why his precautions had failed. Evidently it was not enough
to inspect meat by taste and smell - even minute quanities of ptomaine might
be enough to cause scurvy.

His solution was to move the expedition off of canned meat altogether,
relying entirely on seal meat and penguin. This would be fine while the men
remained on the Discovery, but it left the problem of what to do about the
upcoming sledge journeys. The planned sledging ration was pemmican (a
mixture of dried meat and fat) and biscuit, but since Scott had lost all
confidence in the safety of preserved meat, he had to find a way to replace
the pemmican with seal.

Fresh seal meat would be far too heavy a replacement, so Scott had it
repeatedly boiled to remove as much moisture as possible (in the process
destroying all its vitamin C). This concentrated seal meat was still almost
twice as heavy as the equivalent pemmican, but it was the best he could do.

In November of 1902, Scott, Wilson and Shackleton set out on the
expedition’s main journey. Their goal was to take a dog team as far south as
possible along the Ross ice shelf, and see if they could find a useful route
for an eventual attempt at the Pole.

Things did not go well. Scott inadvertently starved his dogs, making them
impossible to control and nearly useless for hauling. Very quickly, his men
had to start relaying the sledges, which meant walking three miles for every
one mile of southward progress. They began killing the weakest dogs and
feeding them to the remainder (the dogs were so hungry they did not hesitate
to rip their fallen comrades apart). The men themselves could think of
nothing else but food, their rations inadequate for the work of hauling the
sledge.

Wilson, a doctor, checked the men’s gums and legs each Sunday for signs of
scurvy. Shackleton was the first to show symptoms, though he was not told
about this for several weeks. Soon Scott and Wilson were showing symptoms as
well. Before long Shackleton was weak, had begun to cough up blood at night,
and was in real danger of physical collapse.

The party barely made it home. For much of the return trip, Shackleton was
unable to pull, staggering alongside the sledges. On their return to the
Discovery, the men were bedridden and in a state of complete physical
collapse, getting up only long enough to eat prodigious meals. Scott
remarked in his journal on the extraordinary lassitude and lack of energy
the disease provoked in him.

Eight years after the Discovery expedition, Scott returned to Antarctica to
make an attempt at the Pole. Mindful of what had happened on his first
journey, he took pains to seek the latest expert advice about scurvy, both
from doctors and from Arctic explorers.

The advice he got was unchanged - scurvy was an acidic condition of the
blood caused by ptomaines in tainted meat. The legendary explorer Fridtjof
Nansen had some particularly curious advice - if he found himself in
extremis, Nansen said, it was better to choose cans of meat that were
completely rotten over cans that were only slightly spoilt, since the
ptomaines were more likely to have broken down in the former.

This time Scott made sure to provide his men with fresh seal meat, and
scurvy was not a problem in the main camp. In the austral winter of 1911,
Wilson, Bowers, and Cherry-Garrard went on a phantasmagoric five week
journey to try and collect the eggs of the empreror penguin. This journey,
which gave Cherry-Garrard’s book its title, took place in complete darkness
and temperatures that dropped below -77˙ Fahrenheit. The men, forced to
relay and searching for their footprints by candlelight, sometimes made as
little as a mile of progress a day. When Cherry-Garrard’s clothes were
weighed on his return, they contained twenty four-pounds of ice. That the
men survived defies belief - there has never been another journey in the
Polar night, even with modern equipment - but they did return, and to
Scott's great relief showed no symptoms of scurvy.

One of Scott's goals for the winter journey had been to determine the proper
ration for sledging up on the Polar plateau, where the men would have to
hike for several weeks at altitudes above 10,000 feet. After some tinkering
with proportions, the men on the Winter Journey had settled on a satisfying
ration, and Scott decided to adopt it unchanged for his on trip later that
year:

<missing image>

Scott's Polar ration: 450g biscuit, 340 grams pemmican, 85g sugar, 57g
butter, 24g tea, 16g cocoa. This ration contains about 4500 calories
(sledging requires 6500) and no vitamin C.

Scott left camp with 16 men on November 1, 1911. His plan was to lay depots
along the route, and send groups of men back at intervals until he was left
with three companions on the great plateau south of the Beardmore Glacier.
The expedition used men, dogs, ponies (slaughtered and fed to the dogs at
the foot of the glacier), and a pair of experimental motorized sledges that
broke down after just a few miles on the ice.

Scott sent back his men in stages; each group had a progressively harder
time making it back to camp. The last group, sent back from the top of the
Beardmore, was led by Edward Evans, who quickly developed a severe case of
scurvy. After bravely walking most of the distance, he became incapacitated
and had to be left on the ice in the care of a companion while the third man
in the group force-marched the thirty remaining miles to camp to summon a
rescue team.

Scott, oblivious to this ominous development, pressed onwards. The rest of
his story is well known. Norwegian tents at the Pole, an increasingly
desperate return, two in his group sickening and dying, then a terrible
blizzard eleven miles short of his last depot; the three men freezing to
death in their tent.

The evidence that the Polar Party suffered from scurvy on their return trip
is strong but circumstantial. The wounds that would not heal, the sudden
death of Seaman Evans during the descent down the Beardmore, their great
weakness are all consistent with the disease. Both Scott and Wilson would
have easily recognized the symptoms, but it is possible that they would have
chosen not to record them. There was a certain stigma with scurvy,
especially in their case, having taken such pains to forestall the disease.
Scott had nearly left any mention of scurvy out of his 1903 report, before
deciding to do so for the cause of science, and it’s possible he felt a
similar reticence now.

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.

---

There are several aspects of this 'second coming’ of scurvy in the late 19th
century that I find particularly striking:

First, the fact that from the fifteenth century on, it was the rare doctor
who acknowledged ignorance about the cause and treatment of the disease. The
sickness could be fitted to so many theories of disease - imbalance in vital
humors, bad air, acidification of the blood, bacterial infection - that
despite the existence of an unambigous cure, there was always a raft of
alternative, ineffective treatments. At no point did physicians express
doubt about their theories, however ineffective.

Second, how difficult it was to correctly interpret the evidence without the
concept of "vitamin". Now that we understand scurvy as a deficiency disease,
we can explain away the anomalous results that seem to contradict that
theory (the failure of lime juice on polar expeditions, for example). But
the evidence on its own did not point clearly at any solution. It was not
clear which results were the anomalous ones that needed explaining away. The
ptomaine theory made correct predictions (fresh meat will prevent scurvy)
even though it was completely wrong.

Third, how technological progress in one area can lead to surprising
regressions. I mentioned how the advent of steam travel made it possible to
accidentaly replace an effective antiscorbutic with an ineffective one. An
even starker example was the rash of cases of infantile scurvy that
afflicted upper class families in the late 19th century. This outbreak was
the direct result of another technological development, the pasteurization
of cow's milk. The procedure made milk vastly safer for infants to drink,
but also destroyed vitamin C. For poorer children, who tended to be
breast-fed and quickly weaned onto adult foods, this was not an issue, but
the wealthy infants fed a special diet of cooked cereals and milk were at
grave risk. It took several years for infant scurvy, at first called
"Barlow's disease", to be properly identified. At that point, doctors were
caught between two fires. They could recommend that parents not boil their
milk, and expose the children to bacterial infection, or they could insist
on pasteurization at the risk of scurvy. The prevaling theory of scurvy as
bacterial poisoning clouded the issue further, so that it took time to
arrive at the right solution - supplementing the diet with onion juice or
cooked potato.

Fourth, how small a foundation of evidence was necessary to build a soaring
edifice of theory. Lind’s famous experiment, for example, had two sailors
eating oranges for six days. Lind went on to propound a completely
ineffective method of preserving lemon juice (by boiling it down), which he
never thought to test. One of the experiments that ’confirmed’ the ptomaine
theory involved feeding a handful of monkeys canned and fresh meat. The
fructivorous monkeys died within days; the ones who died last, and with the
least blood in their stool, were assumed to be the ones without scurvy. And
even these flawed experiments were a rarity compared to the number of flat
assertions by medical authorities without any testing or basis in fact.

Finally, that one of the simplest of diseases managed to utterly confound us
for so long, at the cost of millions of lives, even after we had stumbled
across an unequivocal cure. It makes you wonder how many incurable ailments
of the modern world - depression, autism, hypertension, obesity - will turn
out to have equally simple solutions, once we are able to see them in the
correct light. What will we be slapping our foreheads about sixty years from
now, wondering how we missed something so obvious?

In the course of writing this essay, I was tempted many times to pick a
villain. Maybe the perfectly named Almroth Wright, who threw his
considerable medical reputation behind the ptomaine theory and so delayed
the proper re-understanding of scurvy for many years. Or the nameless
Admiralty flunkie who helped his career by championing the switch to West
Indian limes. Or even poor Scott himself, sermonizing about the virtues of
scientific progress while never conducting a proper experiment, taking
dreadful risks, and showing a most unscientific reliance on pure grit to get
his men out of any difficulty.

But the villain here is just good old human ignorance, that master of
disguise. We tend to think that knowledge, once acquired, is something
permanent. Instead, even holding on to it requires constant, careful effort.
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