it. But in constant and regular Alternations of Contraction and Dilatation, it differs exceedingly from all the Muscles of the Body.
This reciprocal Æstus of the Heart has given the Learned abundance of trouble; who, finding nothing peculiar in the Structure, which shou'd necessarily occasion it, nor any Antagonist, whose re-action should produce it, have been extreamly perplex'd to find out the cause of it.
But passing over the various Opinions of Authors, to avoid being tedious, I shall take notice here only of the very Learned Dr. Lower's, in whose Account of the Systole, however solid and ingenious, I observe something deficient, and whose Hypothesis of the Diastole I think to be precarious and false.
This Excellent Author, having by sound Arguments drawn from the Structure and Mechanism of the Heart, establish'd the Certainty of its Muscular Motion, rests satisfied, without taking notice of any Assistance, that the Heart receives from any other Part, except from the Brain, by the means of the eight pair of Nerves.