The problem was that many died and no treatments had been effective, so an experiment was done in which Lind compared six different treatments. And citrus fruits showed to be much better than other treatments.

This experiment is generally regarded as the first controlled trial in clinical science. The experiment relates to the possible cures of scurvy, not to its causes. The traditional view is that Lind was much less innovative in his research on the causes of scurvy. In 1867 the French naval surgeon H. Rey, in his analysis and critique of Lind�s Treatise of the Scurvy, complained that, while Lind relied only on experiments in matters of therapeutics, his theory on the causes of scurvy was based on �ideas that are far removed from any kind of scientific precision.