The Polyelectrophysiograph: An Instrument for Teaching and Research in Biological Sciences Available to Purchase

(1) The important characteristics of three groups of luminescent materials (phosphor) used in the construction of screens for cathode-ray tubes have been described and some of the practical applications of these characteristics pointed out. (2) Some of the advantages and disadvantages of the ``slow'' screen tube, RCA 910, are discussed briefly and a description of the application of this tube to the study of heart sounds, or action currents from the heart and brain or peripheral nerves is made. (3) A method of erasing persistent phosphorescent tracings by means of exposing the tube screen to red light has been presented. (4) The general arrangement of the ``slow'' screen and ``fast'' screen cathode-ray tubes together with some of the associated control equipment of the polyelectrophysiograph has been described. This new laboratory instrument has proved extremely useful for both teaching and research.