SPHYGMOGRAPH

n. Sfi2g'mo-gra3f. Lat., sphygmographium (from ox^uyfids, the pulse, and ypafatv, to write). Fr., sphygmographe. Ger.. S., Pulszeichner, A recording pulsimeter, especially a sphygmochronograph. [a, 17.] Czermak's s. A s. in which the pulse pad communicates with a small mirror that throws a beam of light on a screen or on sensitive paper, [a, 34.] Differential s. Two small conjoined gla tubes containing MAREY'S SPHYGMOGRAPH. mercury and closed by two fine caoutchouc membranes. On the surface of each column of mercury floats a registering style. The tubes are attached to an artery and the accompanying vein and indicate the character of the arterial and venous impulses. [0. Ozanam, " Gaz. hebdom. de med. et de chir.," Jan. 29. 1886, p. 78 (a, 34).] Keyts's s. An instrument consisting of a rubber-membrane-covered pulse pad, gla transmi ion tubes, a manometric tube, a water reservoir, a lever that registers the pulse tracing on a writing surface, and a chronograph, [a, 34.] Landois's (gas) s. A s. in which the pulsations are transmitted to a reservoir of gas, so that the oscillations in the height of a flame of the lighted gas are synchronous with the pulse waves, [a, 34.] Ozanam 's s. An instrument consisting of a small elastic bulb communicating with a tube containing a column of mercury. On the surface of the latter is a float that supports a slender rod holding a pen. The pen is kept in contact with a moving band of paper by means of a magnet placed behind the paper. [L, 88 (a, 34).] Vierordt's s. A s. consisting of a beam from which are suspended two levers of unequal length that articulate by means of a metal square attached to their free extremities. An index which is in contact with a revolving cylinder is attached to the square, and it oscillates coincidently with pulsations communicated to the longer lever. [L, 88 (, 34).] [s. 516]