A text book of physiology . artificial respiration kept up, under which circumstances no 1 Cht. med. Wis*. 1866, p. 179. 2 These numbers are to be considered merely as instances which have been observed,and not as averages drawn from a large number of cases. F. P. 10 146 ENBO-CARDIAG PRESSURE. [Book i. such aspiration takes place, the pressure in the left ventricle maysink as low as —24 mm. The occurrence of so marked a negativepressure in the ventricular cavities shews that these cavities, butespecially the left, exert a considerable suction power duringdiastole. The heart in fact appears to
A text book of physiology . artificial respiration kept up, under which circumstances no 1 Cht. med. Wis*. 1866, p. 179. 2 These numbers are to be considered merely as instances which have been observed,and not as averages drawn from a large number of cases. F. P. 10 146 ENBO-CARDIAG PRESSURE. [Book i. such aspiration takes place, the pressure in the left ventricle maysink as low as —24 mm. The occurrence of so marked a negativepressure in the ventricular cavities shews that these cavities, butespecially the left, exert a considerable suction power duringdiastole. The heart in fact appears to act not only as a force-pumpbut also as a suction-pump, thereby aiding to refill itself with bloodat each stroke; the suction of the left ventricle besides greatlyassisting the circulation through the lungs. The results given above are those of Goltz and Gaule!. The principleof then* maximum manometer, Fig. 30, consists in the introduction intothe tube leading from the heart to the mercury column, of a (modified cup- «a^. Fig. 30. The Maximum Manometer of Goltz and Gaule. At e a connection is made with the tube leading to the heart. When the screwclamp Jc is closed, the valve v comes into action, and the instrument, in the positionof the valve shown in the figure, is a maximum manometer. By reversing the directionof v it is converted into a minimum manometer. When h is opened, the variations ofpressure are conveyed along a, and the instrument then acts like an ordinary mano-meter. and-ball) valve, opening, like the aortic semilunar valves, easily from theheart, but closing firmly when fluid attempts to return to the heart. Byreversing the direction of the valve, the manometer is conveited from amaximum into a minimum. When an ordinary manometer is connectedwith a ventricular cavity, the movements of the mercury do not followexactly the rapid variations of pressure of the cavity, and the height ofthe column fails to indicate both the highest and the lowest , as
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