Although oscillometry had previously found widespread use in Europe, it was not until 1927, when Samuels1popularized the method, that it began to be extensively used in the United States. Since then, numerous local articles have appeared2discussing the value of oscillometric readings in the study of peripheral arterial disease. Before my observations concerning the significance and interpretation of oscillometric readings in cases of peripheral arteriosclerosis are presented, some of the well known physical principles on which arterial pulsation is based must be reviewed. When the left ventricle ejects a quantity of blood into the partially filled aorta, pressure changes are suddenly set up in the aorta and in the vessels at the root of the neck. These pressure changes are propagated along the branches of the arterial tree in the form of a wave moving at a speed computed to be eighteen to thirty times as fast