“In every truth attained there is utility, either at hand or among the certainties of the future.”—Paget.
The work of the present essay was devised and prosecuted with the conviction that the points to be established were of interest and importance, and that the graphic method afforded the facility for their successful study.
Our knowledge of velocity of the pulse-wave has all been acquired within a comparatively recent period and still later are our acquisitions in regard to the interval between the beginning of ventricular systole and rise of the aortic pulse. Previous to the present investigation, it had been determined that the pulse-wave velocity and duration of the cardio-aortic interval were both subject to variations, but the real causes of the variations remained to be determined by experimental inquiry and observation.
If, in the following pages, we make frequent reference to our own previous observations, it is because they