The renewed interest in blood pressure, from a medical point of view, and the succession of articles by clinicians appearing on the subject, crowned by Janeway's book just off the press, indicate that the question is proving of more than scientific value, and that it is becoming an established element in diagnosis and treatment. The activity in this direction has necessarily been coincident with and limited by the development of practical methods for accurately estimating this symptom, and as these methods come more and more into general usage, the value of their application and the interpretation of the data derived there from will gradually assume their rightful position in the collective symposium of each carefully reviewed case. Two years ago, while resident at the Johns Hopkins Hospital, I emphasized the necessity for an accurate estimation of arterial tension, not only in the laboratory and in the especially desperate cases