[Histochemical demonstration of free and bound iodine in the thyroid gland]

A new method of the direct chemical demonstration of free and organically bound iodine in the thyroid gland is described. With palladium chloride it is possible to set free organically bound iodine and bring it to precipitation as insoluble palladium iodide in one step. The colored palladium iodide is good visible in the tissue section, but may be made plain after reaction with hydrosulfuric acid or a contrast staining.