Although iodin and products containing it have long belonged to the armamentarium of medical practice, a unique interest in the element was aroused by the discovery by Baumann, in 1895, of its presence in the thyroid gland. There has been no lack of speculation as to the significance of this and the literature is full of conflicting statements as to the possible part that iodin may play in the animal economy. With the accumulation of reliable facts regarding the distribution of iodin in nature it seems more and more probable that its appearance in special tissues, notably the thyroid, in comparatively greater abundance than elsewhere, is not a mere accident.
Undoubtedly the true biologic significance of iodin will become more and more elucidated when our knowledge of its distribution in living forms has been extended far more widely than at present. To Dr. Cameron of the University of Manitoba at