From a comparative study of the first Latin edition of William Harvey's De motu cordis published in 1628, and the first English edition published in 1653, it is argued that the latter is the printed copy of Harvey's original manuscript written in the vernacular. It will also be shown that Harvey's pre-circulation theory described the heart as an impulsor of blood for several years before his discovery of the circulation of the blood. The crucial aspect of his description was a (...) new explanation of the cause of the arterial pulse as felt at the extremities. (shrink)