Our excuse for introducing for discussion so time-worn a subject as the symptomatology of myxedema is that the recent introduction of artificial hypothyroidism as a form of therapeutics makes the topic once more timely. If one is to steer successfully between the Scylla of congestive heart failure or angina pectoris on the one hand and the Charybdis of myxedema on the other, some precise information concerning the relation of symptoms to metabolic rates, time intervals and thyroid rations becomes necessary. Coordinated clinical observations and determination of the metabolic rate on patients with myxedema have been accumulating in our clinic over a period of twenty years (more than two hundred and forty cases). This material provides an excellent source of information. Many of our patients have been under observation year after year, so that our estimate of the relation of symptoms to the height of the metabolic rate is based on