I. INTRODUCTION AND SUMMARY
Of all attempts at organotherapy, the most brilliant results have been obtained with thyroid preparations. This fact lends especial interest to the isolation of the active substance of the thyroid, as well as its employment in the treatment of disease. Some time ago a crystalline body containing upwards of 60 per cent. of iodin was prepared from the thyroid by Kendall of the Mayo Clinic. Observations made on cretins and myxedema patients justify the view that this substance is to be regarded as a hormone having the functions ascribed to the thyroid. Some time back Dr. Kendall generously presented me with a quantity of this material for independent study.The present article describes therapeutic experiments with this thyroid preparation, the effect of thyroid administration on metabolism, and of diet in thyroid disease. In view of the importance of a thorough study of the thyroid hormone, it