From the Royal Postgraduate Medical School and Hammersmith Hospital,

AUTHORS ’ YNOPSIS. In a group of 50 healthy young females, pressure was determined from the right brachial artery using a direct recording technique and a standard indirect sphygmomanometer. Simultaneous recordings showed that there was a close correlation between the onset of Korotkof sounds (phase I) and systolic pressure. Disappearance (phase V) correlated with diastolic pressure better than mufling (phase I V) , but there was a very wide variation for both. The indirect auscultatory method for recording arterial blood pressure is accepted as a rapid and accurate technique which has the advantage of a simple and rational physiological explanation (Burton, 1953). The accuracy of the technique has been tested on many occasions by the simple ex-periment of recording direct arterial pressures at the same time as indirect recordings are mad