VITAMIN B—ITS NATURE AND ITS WORKS

Although it has been more than twenty years since Professor Pekelharing, noted Dutch investigator, hazarded the opinion that "there is a still unknown substance in milk, which, even in very small quantities, is of paramount importance to nourishment," the isolation of vitamins in pure form remains an unsolved problem for the research worker in the laboratory. As long ago as 1887 a commission from the Netherlands was studying beriberi, and, indeed, since that time the search for the elusive essential substance has been constant. In a recent survey of the biochemical investigations of vitamin B, Kruse and McCollum¹ of the biochemical laboratory of Johns Hopkins University have traced the gradual development of interest in the nature of this vitamin. The demonstration of the existence of the vitamin was not accepted without a struggle. It was not until 1920 that Abderhalden agreed that there was no longer doubt of the