It was early noted that the roentgen ray has a remarkable effect on lymphoid and endocrine tissue. So far as the latter is concerned, the use of the roentgen ray has been confined largely to the thyroid and thymus. In this study we have attempted to determine the effect on the suprarenals of irradiation of the suprarenal region in the intact animal.
The first work on this subject was carried out under the inspiration of Vasquez, who believes that hypertension is probably an evidence of increased adrenal activity and the investigations of his school have been made with this point in view. Zimmern and Cottenot1 studied four patients with hypertension, whose systolic pressure as recorded by the Pachon apparatus was over 220 mm. of mercury. They then exposed the suprarenal region of these patients to roentgen rays, giving from three to fourteen exposures, and noted that the pressure fell and