A ship's surgeon ran one of history's first controlled trials — on twelve scurvy patients

Scurvy was the deadliest killer aboard long voyages, rotting gums and reopening old wounds, and nobody knew why. In 1747, surgeon James Lind of HMS Salisbury decided to test the rival cures head-to-head.

He took twelve sailors with scurvy, kept their diet identical, then split them into six pairs — each receiving a different supplement: cider, sulfuric acid, vinegar, seawater, a spiced paste, or two oranges and one lemon a day. By holding everything else constant, only the treatments differed. The citrus pair recovered so fast that one sailor was fit for duty within six days, while every other remedy failed. That structure — matched groups, a single varied factor — is the backbone of the controlled experiment still used today.

The maddening part is what happened next, or rather didn’t. The Royal Navy did not issue lemon juice fleet-wide until around 1795, nearly half a century later, a push finally driven by physician Gilbert Blane. Lind himself muddied the case: he came to favor a boiled-down concentrate called a ‘rob’ that was easier to store but whose heat destroyed the very vitamin C doing the work.

When citrus rations did arrive, the payoff was strategic, not just medical. Scurvy-free crews could stay at sea far longer, handing Britain a real naval edge during the Napoleonic Wars.

Lind’s design outran his theory by more than a century: vitamin C — the active ingredient he could never name — wasn’t isolated until the 1930s, work that earned Albert Szent-Györgyi the 1937 Nobel Prize.