Early in the study of peripheral pulse volume by means of the plethysmometer described by Johnson,1 it became evident that in persons suffering from occlusive disease of the arteries of the extremities, the pulse volume wave deviated sharply in size and contour from that obtained in normal persons. This change was found to be remarkably constant and could be repeated day after day, so that it was frequently possible to identify the patient by the appearance of the tracing (fig. 3). These changes were more uniform than were the deviations from the normal in persons with either valvular defect or myocardial impairment.1
It will be demonstrated that the character of the wave is not dependent on changes in the peripheral capillary bed, except that as in the normal state1 and in Raynaud's disease the size of the wave diminishes with capillary and arteriolar vasoconstriction. Immediately after the