INTRODUCTORY
The material on which this paper is based was obtained at the suggestion of Prof. Friedrich von Müller, in his wards at the Allgemeine Krankenhaus, links der Isar, in Munich. We intended originally to take as the subject of the paper, the presphygmic period, i. e., the time between the beginning of ventricular systole and the opening of the aortic valves. As our work advanced, however, we had reason to doubt the accuracy of the presphygmic period as determined by our method, or, indeed, by any present method (except possibly in the case of aneurysms), and we, therefore, decided to discuss primarily the Vs-S time, or the time passing between the beginning of ventricular systole, and the arrival of the pulse wave at a given point on the subclavian artery.As we shall show, the presphygmic period obtained in the usual Avay varies