Notwithstanding these curious and erroneous speculations there was not wanting exact and wide knowledge of the anatomy of the human body. Indeed, before Harvey was born there had lived and died a most remarkable man known to fame as the “Father of Anatomy.” This was Vesalius. Vesalius’s knowledge of the human body was so profound that the only wonder is that he did not forestall Harvey in the discovery of the circulation. As the result of dissections of the body at the time when they could be carried out only with great difficulty, and often at the risk of severe penalties, Vesalius published, when only twenty-eight years of age, a treatise on Anatomy[3] which cannot fail to excite the astonishment and admiration of any modern acquainted with the subject. This work is illustrated with fine engravings made from drawings by John Calcar, a Flemish artist, and pupil of Titian.[4] [3] De humani Corporis fabrica, 1543. [4] Vasari: “Lives of the Painters,” vols. iii. 519, v. 402 (Bohn’s ed.). The distribution of the bloodvessels in the lungs and many other parts of the body, the general structure of the heart, the valves in the veins, were all known before Harvey arrived on the scene. More than this, the circulation through the lungs, or the Pulmonary Circulation, appears to have been known to one person at least. Michael Servetus, famous for his martyrdom on account of his religious opinions, in one of his theological works[5] does actually describe the blood as passing from the right side of the heart to the left through the lungs, and gives good reasons for his belief. Servetus, in his early days, had been with Vesalius prosector to John Guinterius of Andernach when Professor of Anatomy at Paris. Guinterius[6] speaks with admiration of the knowledge and abilities of his two young assistants. Like Vesalius, Servetus was therefore well acquainted with the anatomy of the body; but more, he was a physiologist; and no doubt when the cruelty of theological dispute sent him to the stake at the age of forty-four, it deprived physiology of a most promising investigator. The book in which the account of the Pulmonary Circulation is found has a most curious history. All copies of it, except one, were burnt with Servetus. This copy became the property of D. Colladon, one of his judges. After passing through the library of the Landgrave of Hesse-Cassel it came into the hands of a Dr. Mead, who undertook in 1723 to issue a quarto edition of it, but before completion the sheets were seized at the instance of Dr. Gibson, Bishop of London, and destroyed. The Duc de Valise is said to have given 400 guineas for the original copy, and at his sale it brought 3,810 livres. It is now in the National Library at Paris. It may well be questioned therefore whether the discovery of Servetus was ever known to the anatomists, including Harvey, who wrote after his death. One of these was Realdus Columbus, who published a