Total thyroidectomy has proved an effective therapeutic procedure in the treatment of angina pectoris (Lev and Hamburger,1Blumgart, Levine and Berlin,2Levine and Eppinger,3Claiborne and Hurxthal,4Clark, Means and Sprague,5Scherf,6Singer7and others). Eppinger and Levine8expressed the belief that the complete removal of the thyroid gland alters the response of the cardiovascular system to epinephrine and that it is the alteration of this mechanism which may, in a measure, be responsible for the relief of anginal pain. Likewise Shambaugh and Cutler9reached the conclusion that the beneficial effect of removal of the thyroid gland in angina pectoris may be due, in a part at least, to a diminished effectiveness of the physiologic output of epinephrine. Barbour and Prince10ascribed to epinephrine a causative role in angina pectoris as early as 1915, when they showed that it constricts