James Lind and the cure for scurvy
When George Anson left Britain in 1740 on his expedition to the Pacific, he took 1,854 men with him. He captured the most valuable treasure ship in existence at the time, circumnavigated the globe, and returned home in 1744 with only 188 souls. The majority of those who had perished on the voyage, had done so from disease, principally scurvy. At the time this was thought to be a painful, but inevitable price to be paid for the considerable achievements of Anson’s voyage. Scurvy was an accepted risk of lengthy ocean travel. Between the 16th and 18th centuries it has been estimated that the disease killed two million sailors globally. But news of Anson’s appalling casualty rate did shock a young, newly qualified, Scottish naval surgeon called James Lind, who became determined to try and find a cure for the killer disease.
Scurvy is a particularly difficult illness to investigate, largely because it does not have a positive cause, but instead is the result of an absence in the diet. Humans, along with the other Great Apes and, curiously, guinea pigs, are unusual amongst mammals in that they need to ingest Vitamin C to be able to make collagen. Collagen is a major component of connective tissue, the glue that holds the body together. Without it, teeth loosen and fallout, old wounds reopen and broken bones un-knit. If left untreated, worse follows, as the internal structure of the body begins to disintegrate, and ultimately the patient suffers a painful death. Vitamins were not discovered until the twentieth century, and the fact that most carnivorous mammals seemed to survive perfectly well without any fruit or green vegetables only served to obscure the true cause of scurvy.
But there was some hope. Seaman had long known that eating green vegetation could cure a sufferer of scurvy. When Anson’s men started to exhibit the first symptoms of the disease during his passage around Cape Horn, he made his way to the fertile island of Juan Fernández where his men could gorge on greenery. During Lind’s research he discovered the observations of John Woodall, a surgeon of the British East India Company in the previous century, who had noticed that citrus fruit had an even more dramatic effect on patients. But Lind was not the only doctor working on a cure. A spectrum of people, ranging from respected men of science to dangerous crackpots all seemed to have a competing remedy to champion. Perhaps the most bizarre was a proposal that the drinking of seawater would cure the ailment. The Navy Board, always with an eye on controlling costs, were understandably enthusiastic about this last solution. What was needed was some objective, scientific research, and Lind resolved to take matters in hand, with an approach to the problem that was truly groundbreaking.
In 1747, aboard his ship, the Salisbury, he carried out what was to be the world’s first randomised clinical trial. After a period of two months at sea, the first signs of scurvy began to appear amongst the crew. When he had twelve cases to treat, he divided them into six pairs. All of the men received the same care, and exactly the same food and drink, plus one of the various proposed treatments. The first pair was fed a dose of cider, the next elixir vitriol (dilute sulphuric acid), another was given vinegar, the fourth seawater, the next a paste of various plant extracts, and the final pair was given two oranges and a lemon each day. The result of the trial was quite conclusive, when the pair of seamen fed on the fruit made a rapid and immediate recovery.
It took some time for Lind’s discovery to be implemented in the navy, not least because Lind was unable to explain why the cure worked. There was no knowledge then of the existence of vitamins, and instead Lind had to rely on the ancient theory of balancing humours that still dominated 18th century medicine. Lind thought, wrongly, that it was the acid in the fruit that was acting on his patients. This led to further trials to find lower cost alternatives to citric acid. However, in time, a daily measure of lemon juice was introduced into Royal Navy sailors’ diets. It had the instant effect of banishing scurvy from the fleet. When war with Spain cut off the supply of Mediterranean fruit, tropical limes from the West Indies were substituted, causing American sailors to refer to their British equivalents as ‘Limeys.’
Almost thirty years after George Anson and his disease ridden survivors returned home, another Royal Navy captain, James Cook, left Britain bound for the Pacific in the Endeavour. Cook showed an exceptional regard for the welfare of his men, and was determined that his voyage would not be blighted by unnecessary death and suffering. He was an early convert to Lind’s work, and as a result he paid close attention to his men’s diet. He made sure that he stopped regularly to buy fresh fruit and vegetables, and he carried onboard stocks of pickled cabbage to feed them with when this ran out. His voyage of exploration lasted a similar time to Anson’s, but unlike the earlier circumnavigation, Cook lost no one to scurvy.
