In delineating the history of a vitamin, we can often recognize four chronological phases. First, there is the description of a disease of unknown etiology, and second, there is the description of an empirical cure for the disease. Following this step, and often closely associated with it, is the identification of the curative factor – which perforce then becomes known as a vitamin. In the fourth phase the mode of action of the vitamin in preventing the deficiency disease is characterized.

The history of vitamin C (ascorbic acid) conforms to this general pattern. The characterization of the deficiency disease (scurvy) and the empirical discovery of a cure for it are, properly speaking, a part of the history of scurvy and have been dealt with elsewhere in this work. But this chapter is concerned with the subsequent history of the antiscorbutic factor, which conveniently presents itself in three chronological stages: (1) the somewhat ill-defined and open-ended period – from the beginning of the nineteenth century to the 1920s – when the vitamin had the existence of an “unrevealed presence” and was known to exist only because of its preventive influence on the disease scurvy (just as, during the same period, the perturber of Uranus was known to exist long before the “discovery” of the planet Pluto); (2) the 1920s and the 1930s, when vitamin C was named, isolated, and its molecular structure revealed (in that order); and (3) the modern post-1940 period, with its emphasis on the characterization of the biochemical role of vitamin C in preventing scurvy and, more recently, the debatable “extra-antiscorbutic” roles sometimes attributed to it.