It has been only within recent years that the mild states of hypothyroidism have received any attention. The most recent textbooks on diseases of the thyroid gland still devote considerable space to cretinism and myxedema but say very little, or do not mention at all, the group of cases which present symptoms which appear to be associated with lessened thyroid secretion but which never reach the stage of myxedema. That there is such a group of cases is attested to by articles now appearing in the literature from widely separated parts of this country. Kocher in 1904 was the first to call attention to this group as a possibility, but only since the development of clinical metabolimetry has it been possible to recognize the condition with any degree of accuracy.
The thyroid gland, unlike the pancreas or the suprarenal glands, is not absolutely necessary to maintain life. "It is not