Twelve Sailors, Six Remedies, One Trial

By the mid-eighteenth century, scurvy had killed more British sailors than enemy action. The disease that began with bleeding gums and ended with old wounds reopening was, on any long voyage, almost guaranteed. Theories of cause were a soup: bad air, salt rations, lack of fresh meat, idleness. Roughly a hundred remedies had been proposed.

In May 1747, James Lind, a 31-year-old surgeon's mate aboard HMS Salisbury, took twelve sailors with clear scurvy and divided them into six pairs. He kept their diet identical and assigned each pair a different supplement: a quart of cider; 25 drops of elixir of vitriol (dilute sulfuric acid); six spoonfuls of vinegar; half a pint of seawater; a paste of garlic, mustard, and balsam with barley water; and two oranges and a lemon. The fruit pair ran out of supplies in six days, but by then one was fit for duty and the other almost so. None of the other remedies came close.

Lind published his Treatise on the Scurvy in 1753. The book sold poorly. The Royal Navy did not begin issuing daily lemon juice to sailors until 1795 — almost half a century after the experiment and the year after Lind's death — when Sir Gilbert Blane finally persuaded the Admiralty.

The delay was partly Lind's own fault. He proposed concentrating lemon juice into a "rob" by boiling it down for storage; the boiling destroyed most of the vitamin C, and his preferred product was inert. Citrus prevention worked only with fresh or properly preserved juice — chemistry that nobody understood until vitamin C was identified in the 1930s.

What Lind had done, regardless, was the form. Twelve sailors, six treatments, one diet, one outcome. It was the first published controlled clinical trial.