There have been in the past many unemphasized observations of diastolic variability both in patients with arterial hypertension and in those with normal blood pressure. In 1911, Schrumpf and Zabel1found that in their arteriosclerotic patients, in which group they included those with arterial hypertension, the diastolic blood pressure fluctuated almost parallel with the systolic. They noted diastolic variations up to 35 cm. (water sphygmomanometer). Tixier2mentioned that the diastolic tension may undergo important variations. More recently, Fahrenkamp,3referring to a case of "malignant nephrosclerosis," stated that the diastolic blood pressure curve showed fundamentally the same fluctuations as the systolic curve. Kylin,4in a study of the lability in essential hypertension, does not discuss diastolic lability, but in a charted example of the blood pressure of a patient with essential hypertension he shows a variation of 55 mm. of mercury in the diastolic blood pressure during