The laws and mechanics of circulation, with the principle involved in animal movement . ial system synchronous with the action in the heart. AUTOMATISM IN THE VESSELS DEMONSTRATED. 145 the one alternating with the other. In other words, there iscomplete rhythm in both—in the arteries as well as in theheart. The fact must be borne in mind, also, that only one-halfof the cardiac rhythm, or the systole simply, can produce anyeffect in the arteries, since the ventricular diastole can accom-plish nothing with the semi-lunar valves closed, for obviatingreflux in the ventricle, as is the case in dias
The laws and mechanics of circulation, with the principle involved in animal movement . ial system synchronous with the action in the heart. AUTOMATISM IN THE VESSELS DEMONSTRATED. 145 the one alternating with the other. In other words, there iscomplete rhythm in both—in the arteries as well as in theheart. The fact must be borne in mind, also, that only one-halfof the cardiac rhythm, or the systole simply, can produce anyeffect in the arteries, since the ventricular diastole can accom-plish nothing with the semi-lunar valves closed, for obviatingreflux in the ventricle, as is the case in diastole. Now, the monistic theory of the circulation, or a vis a tergosimply, how is it possible to explain the phenomena in thesetracings ? The thing is utterly impossible. A moments reflection will make this obvious. For example:How can the cardiac systole produce the sudden fall in press-ure below zero (Fig. 45, a, b) % If the rise in pressure {a, a) isto be explained by the inrush of blood from the ventricle, how,then, is this opposite movement, or fall in pressure, to be. Fig. 45.—The Variations in Blood-Pressure in the Carotid of a Horse.—Marey. Thehorizontal line between the undulations represents the permanent high pressure inthe arterial system, or zero of pressure in the arteries, while the undulations repre-sent the variations, a, a, the rise in pressure produced by systole in the vessels, andwhich corresponds with diastole in the heart; a, b, the fall in pressure which answersto diastole in the vessels, and corresponds with systole in the heart; c, the dicroticwave. accounted for 1 Surely not by resiliency in the ve-sels/ socalled, for this should produce still higher pressure from thecontraction it would occasion in the vessels, though the termitself is inapplicable to vital action. At any rate, it shouldhave directly the opposite effect to that ascribed—increasing,in place of decreasing, blood-pressure. Then, again, how is it possible to produce the f
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