The quality of an article or commodity, in general, is directly dependent on demand and on competition. That is, if there be a large demand for an article and if a considerable number of firms put it on the market, then its quality is likely to be of a high order. Further, as a large demand will commonly bring about competition, "demand" is the chief factor which affects the purity of an article. As an illustration of the high quality of widely used commodities it is but necessary to mention the exceptional purity of ordinary table-salt and the fact that granulated sugar, almost without exception, barring a little moisture, approaches absolute purity. As further illustrations of high quality one may take flour, calico, pins and needles. It should further be stated that, although our Food and Drugs Act has had a beneficial influence even on these staple articles, their purity