While Daly and one of us1were studying the thyroid during pregnancy, we became interested in our office practice in the frequent occurrence of the clinical syndrome resembling mild hyperthyroidism without changed basal metabolic rate. Patients presenting this group of symptoms were usually seen in office practice and practically never in hospital wards. The clinical picture presented by these patients was similar to if not identical with the syndrome long known and described by various authors under the names of irritable heart, effort syndrome, neurocirculatory asthenia, autonomic imbalance and sympathicotonia.2They also closely paralleled some of the cases described by Miller3in his study of mild hyperthyroidism. Almost all the patients had goiters, for which reason we decided to use iodine therapeutically. Results more than vindicated this practice. None of the patients used in this study had shown abnormal metabolic rates. We nevertheless thought that by the