HARVEY AND HIS
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SUCCESSORS.
HARVEY AND HIS SUCCESSORS. heart with blood was the efficient cause of the blood's motion, this being produced, as we have seen, by the boiling up of the blood when exposed to the imaginary heat residing in the heart. He insists emphatically that the contraction of the heart was a mere collapse due to a temporary cessation of the boiling process. In death the collapse, he remarks, is complete; in the moribund it is nearly complete. To attribute any expulsive force to the heart in this condition would therefore be out of the question. Thus the pulse results not from systole, but from diastole. Indeed, the consideration of the pulse is the main subject in this chapter of Cesalpino, the question of the heart and its motions being quite secondary. It may be stated broadly that the conception of a complete cir- culation of the blood and the conception of the heart as a contractile organ exercising mechanical energy were alike foreign to him.
Nothing is more interesting than the vivid, pithy way in which the true view both of the heart and of the blood is expressed in Harvey's MS. notes. "The heart, when contracting, moves like a muscle," he says. "By the impulse of the heart there is a perpetual movement of the blood in a circle." Again, if I may quote the quaint mixture of Latin and English, "Constat per fabricam cordis sanguinem per pulmones in aortam transferri as by two clacks of a water- bellows to rayse water." The imaginary furnace that had been set up for so many centuries within the human thorax disappeared, and in its place there was an organ of definite construction, comparable with one of Galileo's machines, exercising a measurable amount of energy.
