Recently there has been a resurgence of interest in the subject of hypoparathyroidism and it has become increasingly clear that psychiatric symptoms may frequently be found in patients with hypoparathyroidism, even where no evidence of tetany is present. It is significant that in a survey, in the Cardiff area, of 82 patients who had had a thyroidectomy, Davis et al. (1961) found that mental symptoms (defined as a feeling of uneasiness, tension and anxiety, sometimes with attacks of panic, often with depression) occurred in 66 per cent. of 26 patients whose plasma calcium was below 9·3 mgms/cent, in 51 per cent. of 31 patients whose plasma calcium lay between 9·3 and 9·8 mgms./cent. and in 35 per cent. of 23 patients whose plasma calcium was above 9 · 8 mgms./cent. They estimated that at least 24 per cent. of the patients showed partial parathyroid insufficiency, and that this apparently accounted for many minor but disabling symptoms, particularly depression and lassitude. They found that often these symptoms could be cured by the administration of calcium.