Humans are not good at acting on what they already know. As early as 1601, Captain Admiral James Lancaster of the East India Company stumbled on the fact that lemon juice provided an effective prevention against scurvy. By the middle of the 18th century, James Lind, a naval physician, was putting that information to the test in the first recorded randomised control trial (RCT). Lind took 12 men suffering from the symptoms of scurvy and divided them into six pairs, treating each with one of a selection of recommended but untested remedies borrowed from other physicians. These included daily doses of a quart of cider; 25 drops of 'elixir of vitriol'; half a pint of sea-water; a nutmeg-sized paste of garlic, mustard seed, horseradish, balsam of Peru and myrrh gum; two spoonfuls of vinegar; and (rather more effectively) two oranges and one lemon. By the end of the week's treatment, the men who had been fed on citrus fruits were the only ones to show signs of improvement in their symptoms. In spite of this unequivocal evidence, it still took another half century for the Royal Navy to make a portion of citrus fruits a standard addition to sailors' rations - and, even then, only with the campaigning and support of Lind's advocates. In the Seven Years' War (1756-63), Britain raised 185,899 sailors: 1,512 died in action, while 133,708 died of scurvy. However, the Royal Navy was faster at curing scurvy than its main naval opponents - one reason why it was able to win the Battle of Trafalgar against a larger force of scurvy-ridden French and Spanish ships (Leigh, 2018).