Originally published in Pearson's Weekly (C. Arthur Pearson Ltd.) vol.1 #31 (21 Feb 1891).
It is a suggestive fact that there are usually two claimants for the honour of discovering an important fact in science. Anyone familiar with the history of discoveries and inventions can recall many illustrations of this singular fact.
In mathematics we have the German Leibnitz disputing with the English Newton as to which of the two discovered the method of fluxions. In astronomy Adams, the Englishman, shares with Leverrier, the Frenchman, the honour of discovering the planet Neptune. Professor Morse, an American, had to contend with Mr. Wheatstone, the Englishman, for the honour of having invented the telegraph.
The credit of discovering the circulation of the blood is given to William Harvey, an eminent London physician of the seventeenth century. This discovery, which revolutionised the practice of medicine, was made known by Harvey, it is said, in 1616, to his classes in surgery. In 1628 he published it to the world in a book dedicated to Charles I.
The Italians ascribe this important discovery to Father Paul Sarpi, a learned Venetian monk, who died in 1623, at the age of seventy-one. Archdeacon Dixon says that, from personal examination of the controversy, he is satisfied that the world is indebted to Sarpi for this great discovery.
Sarpi was a diligent student of natural philosophy, medicine, and anatomy. In a journal published in 1634 it is stated that Bart discovered the circulation of the blood, but did not make it public. His reticence was due to his fear of the Inquisition, whose hostility to scientific discoveries was well known, and with whom Sarpi had had trouble in his efforts to reform the Roman Church.
He did, however, reveal the secret to his physician, Aquapendente, who had saved his life when wounded by Roman assassins. The physician wrote a book on the subject, based on Sarpi's notes. But he also was afraid that the publication of such a novel heresy would get him into trouble with the Inquisition. He therefore placed his manuscript in the library of St. Mark's.
Aquapendente afterwards removed to Padua, where he was appointed professor. Among his pupils was a young Englishman, with whom he became so intimate that he revealed to him Sarpi's discovery. This young Englishman was Harvey. On his return to England, and after the death of Sarpi, in 1623, he claimed the honour of having made the discovery.