“…McHargue and his associates have studied the significance of copper, manganese, zinc, iodine, and boron in the nutrition of microorganisms, plants, and animals. They found 14.04 parts of iodine per billion in the water supply of Lexington, Ky. (26). They also report (27) the determination of iodine in 439 samples of soil drawn from the important geological areas of Kentucky.…”