James Lind's Scurvy Trial (1747): An Early Clinical Trial

James Lind’s scurvy trial was an experiment carried out by a Scottish naval surgeon aboard HMS Salisbury in May 1747. By giving twelve sick sailors six different remedies, Lind showed that oranges and lemons cured scurvy far better than the alternatives. It is often described as one of the first controlled clinical trials, although its lesson took nearly half a century to change naval practice.

Background: the scourge of the sea

Scurvy is a disease caused by a lack of vitamin C. Without fresh fruit or vegetables, sailors on long voyages developed swollen and bleeding gums, loose teeth, bruising, aching limbs and exhaustion; old wounds could reopen, and many died.

In the age of sail scurvy killed more seamen than combat. The most notorious example in Lind’s time was Anson’s voyage round the world of 1740–1744, in which the squadron lost well over half of its men, the great majority to disease, with scurvy prominent among the causes.

Remedies were many and contradictory. Some writers, such as John Woodall in The Surgions Mate (1617), had recommended lemon juice, but others favoured acids, vinegar, sea water or purges. Physicians largely believed scurvy came from damp air, bad food or blocked perspiration.

Who was James Lind

James Lind was born in Edinburgh on 4 October 1716. He was apprenticed to an Edinburgh surgeon in 1731 and joined the Royal Navy as a surgeon’s mate in 1739, serving in the Mediterranean, off West Africa and in the West Indies.

By 1747 he was surgeon of HMS Salisbury, a 50-gun ship serving with the Channel Fleet. Scurvy broke out among the crew during a cruise in the spring of that year, giving him the chance to test the competing cures.

The experiment aboard HMS Salisbury

On 20 May 1747 Lind selected twelve men with scurvy whose cases, he wrote, were “as similar as I could have them”. They were housed together in one part of the ship and given the same basic diet of gruel, mutton broth, puddings, biscuit and similar food.

Lind then divided them into six pairs, each receiving a different supplement:

• a quart of cider a day;
• twenty-five drops of elixir of vitriol (dilute sulphuric acid) three times a day;
• two spoonfuls of vinegar three times a day;
• half a pint of sea water a day;
• two oranges and one lemon a day;
• a paste, or electuary, of garlic, mustard seed, horseradish, balsam of Peru and gum myrrh.

The results were striking. The two men given citrus fruit improved fastest; one was fit for duty after six days, when the supply of fruit ran out, and the other was well enough to nurse the rest. The cider drinkers showed slight improvement, while the others got little better.

A Treatise of the Scurvy

Lind left the Navy in 1748, took a medical degree at Edinburgh and practised there. In 1753 he published A Treatise of the Scurvy, dedicated to Lord Anson, which described his trial and reviewed the earlier literature at great length.

The treatise did not present citrus as a simple, single cure. Lind still believed scurvy had several contributing causes, especially cold, damp conditions that stopped the body from perspiring, and he recommended dry quarters and good food as well as fruit.

He also proposed a “rob”, a juice boiled down for storage at sea. Heating destroys much of the vitamin C, so this preserved juice was far less effective than fresh fruit, a weakness no one at the time could understand.

In 1758 Lind became chief physician of the Royal Naval Hospital at Haslar near Portsmouth, then one of the largest hospitals in Britain. He held the post until 1783, wrote on preserving the health of seamen and on tropical fevers, and promoted the distillation of sea water to provide fresh drinking water. He died in Gosport on 13 July 1794.

The slow road to adoption

For decades after 1747, the Navy experimented with many anti-scorbutics, including malt wort, sauerkraut and “portable soup”. On Cook’s first voyage and his later expeditions, strict attention to diet and fresh food prevented any deaths from scurvy, but it was unclear which measure was responsible.

The decisive change came from the physician Gilbert Blane, who had seen citrus work in the West Indies. As a commissioner of the Sick and Hurt Board, he helped persuade the Admiralty in 1795 to issue lemon juice as a regular ration. Scurvy largely disappeared from the Royal Navy in the following years, which historians count as a real advantage in the long wars against France.

In the nineteenth century the Navy switched to cheaper lime juice from British colonies in the West Indies. Limes contain much less vitamin C than lemons, and the preserved juice lost potency, so scurvy returned on some voyages, including polar expeditions.

The true cause was found only in the twentieth century. In 1907 the Norwegian researchers Axel Holst and Theodor Frølich produced scurvy in guinea pigs, and in the late 1920s and early 1930s Albert Szent-Györgyi and others isolated vitamin C, or ascorbic acid.

Legacy

Lind’s trial is now a standard example in the history of medicine. Its design, comparing several treatments in similar patients under the same conditions, anticipated the principle of the controlled trial, and 20 May is marked in some countries as International Clinical Trials Day.

Historians caution against seeing Lind as a lone hero who knew the answer and was ignored. The trial was small, unblinded and not randomised, and Lind himself drew cautious, partly mistaken conclusions. Like Edward Jenner’s smallpox vaccine later in the century, it shows how an experimental result could take years to change practice.

Myths and facts

Myth: Lind discovered vitamin C. He showed that citrus fruit cured scurvy, but he had no idea of vitamins. The concept of vitamins emerged only in the early twentieth century, and vitamin C was isolated in the early 1930s.

Myth: the Navy ignored Lind out of stubbornness. Lind’s own conclusions were cautious and mixed with mistaken theories, his recommended preserved juice worked poorly, and many other remedies seemed to succeed on particular voyages. Faced with conflicting evidence, naval officials did not see citrus as the clear answer until the 1790s.

Myth: limes were chosen because they worked best. Limes were adopted in the nineteenth century mainly because they could be obtained cheaply from British colonies. They were in fact less effective than the Mediterranean lemons used earlier.

Myth: Lind’s was the first comparison of treatments. Earlier physicians had made comparisons of a kind, and the Persian scholar Avicenna had set out rules for testing medicines. Lind’s trial stands out for its clear design and its careful written record.

By the numbers

Timeline

• 1716, 4 October: James Lind is born in Edinburgh.
• 1739: Lind joins the Royal Navy as a surgeon’s mate.
• 1747, 20 May: Lind begins his comparative trial aboard HMS Salisbury.
• 1753: A Treatise of the Scurvy is published in Edinburgh.
• 1758: Lind becomes chief physician at Haslar Hospital.
• 1794, 13 July: Lind dies in Gosport.
• 1795: The Admiralty begins issuing lemon juice as a routine ration.
• 1932: Vitamin C is identified as the anti-scurvy factor.

Why it matters

Lind’s experiment showed that careful comparison could cut through centuries of conflicting medical opinion. Its slow uptake is just as instructive: evidence alone did not change practice until a clear explanation, a practical supply and an influential advocate came together.