1) Originally oxyphil cells are absent in parathyroid of normal rat. It was found that dark chief cells increased and light chief cells decreased in parathyroid of rats in chronic fluorine poisoning. These changes were considered to show retarded function. There were, however, no changes in weight, weighting about one mg.
There were found no changes in thyroid gland, thymus and submaxillary gland. 2) Extirpation of parathyroid glands gave no effect in development of fluorine poisoning. 3) Parotin could not prevent development of fluorine poisoning though occurrence of poisoning was seemed to be somewhat retarded by alleviating interference of ossification of epiphyseal cartilage. 4) General condition of intoxicated rats were deteriorated in most cases by fracturestress and callus formation were not found in such cases. Callus formation were noticed, though slightly poor compaired with in control groups, in poisoned rats whose general condition were not so involved. Histologically, disturbance in osteogenesis and retarded absorption of cartilagenous callus were found.