. The Canadian record of science. Natural history. Rate of Propagation of Venous Pulse. 209 If now one indicates with (a) the distance in centi- metres between the vertical lines marking the beginning of a given wave in the two tracings, with (s) the rate at which the recording surface travels in centimeters, with (^/y~0 t^^6 length of vein being studied, and with (y) the rate of propagation of the pulse in that length of vein, then v = s ^^-^ ' a As regards the presence of a pulse in the veins of the animals experimented on, it may be said that one could always be observed and recorded in the
. The Canadian record of science. Natural history. Rate of Propagation of Venous Pulse. 209 If now one indicates with (a) the distance in centi- metres between the vertical lines marking the beginning of a given wave in the two tracings, with (s) the rate at which the recording surface travels in centimeters, with (^/y~0 t^^6 length of vein being studied, and with (y) the rate of propagation of the pulse in that length of vein, then v = s ^^-^ ' a As regards the presence of a pulse in the veins of the animals experimented on, it may be said that one could always be observed and recorded in the central end of the jugular. In most cases it could also be recorded from the distal end of the jugular and from the femoral; but the- waves were sometimes not sharp enough for satisfactory marking. The estimations reported below were taken. 0 1^.3 Fig. 4.—Pressure tracing from central (below) and peripheral end (above) of external jugular vein. Time in seconds. From a dog. from cases where the markings were considered reliable enough to make the errors very slight. It is a noteworthy fact, that the best tracings were frequently obtained from the smallest and weakest dogs. Similar observations have been made by Gottwald (1) on dogs, and G-erhardt (2) on human subjects. Gerhardt claims to have observed the venous pulse most frequently in weak and anaimic girls. Although a discussion of the form of the venous pulse does not properly find a place in this paper, it is necessary to allude to it briefly in order to have names for the vari- ous waves whose rate of propagation was studied. Fol- lowing Fredericq (4), Gerhardt (2) and others, I distinguish, as may be seen in Fig. 4, a presystolic wave, 0, a systolic. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Natural History Society of Montreal. Montreal, Natur
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