1. The autotransplantation of parathyroid glandules into the thyroid gland and behind the musculus rectus abdominis has been successful in sixty-one per cent. of the cases in which a deficiency greater than one-half has been created.
2. In no instance has the autotransplantation succeeded without the creation of such deficiency.
3. Isotransplantation has been uniformly unsuccessful.
4. Parathyroid tissue transplanted in excess of what is urgently required by the organism has not lived.
5. One parathyroid autograft may suffice to maintain the animal in good health and spirits for many months and possibly for years.
6. Excised or deprived of their blood supply in the course of operation upon the human subject, parathyroid glands should, in the present state of our knowledge, be grafted, and probably into the thyroid gland.
7. Complete excision of the thyroid lobes in dogs may be well borne for a year or more. The myxœdema which usually has manifested itself within a few weeks has not increased after the first few months. May it subsequently diminish with the hypertrophy of accessory thyroids?
8. Parathyroid tissue is essential to the life of dogs, as has been conclusively proved by the result of excision of the sole, sustaining graft.
There may be found, perhaps, in our experiments, explanation of the fact observed by others (Enderlen, Payr) that, when transplanted, thyroid preserves its integrity less well than parathyroid tissue. In the instances recorded the amount of thyroid gland excised may have been insufficient to make possible the fullest success of the transplantation; and particularly so when we consider the extent of the hypertrophy of which the thyroid gland seems capable.