James Lind is considered the first physician to have conducted a controlled clinical trial of the modern era. Dr Lind, whilst working as a surgeon on a ship, was appalled by the high mortality of scurvy amongst the sailors. He planned a comparative trial of the most promising cure for scurvy. His vivid description of the trial covers the essential elements of a controlled trial

On the 20th of May 1747, I selected twelve patients in the scurvy, on board the Salisbury at sea. Their cases were as similar as I could have them. They all in general had putrid gums, the spots and lassitude, with weakness of the knees. They lay together in one place, being a proper apartment for the sick in the fore-hold; and had one diet common to all,

Water sweetened with sugar in the morning; fresh mutton-broth for dinner; at other times light puddings, boiled biscuit with sugar, etc., and for supper, barley and raisins, rice and currants, sago and wine or the like.

Two were ordered each a quart of cider a day.
Two others took twenty-five drops of elixir vitriol three times a day …
Two others took two spoonfuls of vinegar three times a day …
Two of the worst patients were put on a course of sea-water …
Two others had each two oranges and one lemon given them every day …
The two remaining patients, took … an electary recommended by a hospital surgeon …
The consequence was, that the most sudden and visible good effects were perceived from the use of oranges and lemons; one of those who had taken them, being at the end of six days fit for duty … The other was the best recovered of any in his condition; and … was appointed to attend the rest of the sick. Next to the oranges, I thought the cider had the best effects …”