The paper by Taitz and deLacy on Parathyroid Function in Vitamin D Deficient Rickets (Pediatrics, 30: 884, 1962) states: "Although some workers have shown elevation of calcium concentrations by parathyroid hormone in rachitic subjects, the problem is further complicated by reports that tetany associated with rickets or osteomalacia is sometimes refractory to administered parathyroid hormone,6,7 thus raising the possibility that low calcium level may result, not from a failure of the parathyroid gland to keep pace with increased demands, but from an acquired failure of bone and kidneys to respond to increased circulating parathyroid hormone.