IN 1874 Gull1 described a "cretinoid state supervening in adult life in women" which Ord 2 called "myxoedema" on account of the abnormal amount of mucin in the subcutaneous tissues. Halliburton3 later pointed out that "myxoedema" was by no means a constant feature and suggested the term "hypothyroidism." The Clinical Society of London 4 reported, in 1888, in a histological study of 13 such patients with primary hypothyroidism and no goiter, "lymphocytic infiltration, scattered epithelial cells, disappearance of acini and of colloid" in addition to fibrotic replacement of the parenchyma. Similar changes were described over two decades later in "struma lymphomatosa" by Hashimoto 5 in four adult females with goiter but no other symptoms or signs. Since then attention has been drawn to the histological similarities between primary hypothyroidism and Hashimoto's disease.6-10 In 1956 Skillern et al 11 noted the failure of the thyroid gland to respond