Eijkman's contribution to the discovery of vitamins.

The work by Christiaan Eijkman in Batavia (now Djakarta, the capital of Indonesia) between 1890 and 1900, for which he received a Nobel Prize, is reviewed. While searching for a microorganism responsible for beriberi, he found that a condition of polyneuritis, with similarities to beriberi, could be produced consistently in chickens by feeding them polished rice, and that addition of the silverskin removed during polishing prevented this. He showed further that the silverskin did not act by physically preventing the entry of microorganisms into the endosperm, nor was its action explained by the protein and salts that it contributed. His tentative hypothesis was that this fraction contributed an antidote to a nerve poison produced by the fermentation of starch in the chickens' crop. However, his successor continued to use Eijkman's animal model and was able to show that silverskin supplied some unknown factor(s) that was required regardless of whether or not the diet contained starch. Fractionation eventually showed thiamin to be the active factor.