The Iodine Content of Food Materials.*

The relat~ion of iodine to thyroid metabolism has rcccived a large amount of study, but the supply of iodine in food materials had been given no systematic attention until taken up by Forbes.’ What influence its tot,al absence in the diet might have on the development of an animal is problematic, but there has not been a lack of opinion t!hat such an absence or low supply in the foods from certain regions was related to the development of goiter. To this opinion the work of Forbes and Beegle gives no credence. Further, we have learned that the production of hairless and weak pigs in certain regions in the northmest,ern part of the United States is attributed by some to a low supply or absence of iodine in the ration of brood sows. Before the work of Forbes and Beegle appeared, we had under way a quantitative survey of the iodine content of a number of foodstuffs, waters, and samples of common salt used by farm stock. The results secured are in agreement with their data and show a low supply of iodine in plant materials and common salts, obtained from widely separate regions. Our only excuse for publishing these results is that they are confirmatory of the work of others, and in addition summarize our experience with certain methods proposed for the quantitative determination of iodine in organic materials. The first method which we attempted to USC was that of IIrauss,2 in which the iodine is determined calorimetrically as PdI,. This