A Brief History of Vitamin C

The vitamin C deficiency disease, scurvy,  was the scourge of armies, navies, and explorers throughout history. It particularly affected those sailors on long voyages who had little access to fresh fruits and vegetables (high in Vitamin C). Despite some recommendations of transporting these foods on their voyages, 10,000 British sailors died of scurvy in 1594. A Scottish physician, James Lind serving in the British Navy had an idea and developed a "crude"experiment on an upcoming long voyage.

To set the stage for this experiment, a historic account is given us from a 16th century surgeon who describes the scourges of scurvy:

It rotted all my gums, which gave out a black and putrid blood. My thighs and lower legs were black and gangrenous, and I was forced to use my knife each day to cut into the flesh in order to release this black and foul blood. I also used my knife on my gums, which were livid and growing over my teeth...

William Faloon. Misconeptions about Vitamin C, Life Extension: The Science of a Healthier Life, November 2021

James Lind did his clinical trial aboard HMS Salisbury in 1847.  He took 6 groups of two sailors with scurvy and gave the following treatments:

Group 1: A quart of hard cider a day

Group 2: 25 drops of vitriol (sulphuric acid)

Group 3: Six spoonful's of vinegar

Group 4: Half a pint of seawater

Group 5: Two oranges and a lemon (ran out of fruit in a week) but recovered from scurvy in six days. There were no signs of scurvy prevention in any of the other groups (to my knowledge).

Group 6: Spice blend

(The cure of scurvy should have been obvious but Lind wanted to fit his observation into the prevailing ideas of the model of humors as the basic model of disease (described above).   This idea of humors had been around since the Ancient Greeks and taught that the body contains four fluids (the humors - phlegm, blood, yellow bile, black bile) associated with certain personalities (phlegmatics, sanguine, choleric and melancholy). Lind thought that scurvy was associated with the build up of black bile due to blocked sweat ducts and downplayed the power of his discovery to a paragraph buried in the middle of a long book. Despite this the British Navy progressively eliminated  scurvy over the remainder of the century using lime juice and were called "limeys". The rest  of the world did not heed the lesson of  the limeys. In the mid—19th century, during the U.S. Civil War, scurvy was rampant.  Science moves very slowly. (SJF)

"In the original timeline (OTL, our world), germ theory wasn't even on the radar until 1847, when Ignaz Semmelweis made the connection between puerperal fever and doctor hygiene (or lack thereof). This was the first strong proof for germs being the cause of disease, but his theory was ridiculed by the scientific community. It took over ( at least) 30 years before the germ theory was accepted as fact." Wikipedia.