DISCOVERY OF THE CIRCULATION 31 



the book Treating of the Heroic Deeds and Sayings of the Good Pantag- 

 ruel, was published in 1903 (Flint). 



In 1553, Michael Servetus, who is commonly regarded as the dis- 

 coverer of the passage of the blood through the lungs, or the pulmonary 

 circulation, described the course of the blood through the lungs, from 

 the right to the left side of the heart. This description, complete as 

 it is, was merely incidental to the development of a theory in regard 

 to the formation of the soul and the production of what were called 

 animal and vital spirits (spiritus). 



A few years later, Colombo, professor of anatomy at Padua, and 

 Cesalpinus, of Pisa, described the passage of the blood through the 

 lungs, probably without a knowledge of what had been written by 

 Servetus. To Cesalpinus is attributed the first use of the expression 

 "circulation of the blood"; and he also remarked that after ligature 

 or compression of a vein, the swelling is always below the point of 

 obstruction. 



The history of the discovery of the valves in the veins is somewhat 

 obscure, although priority of observation is almost always conceded 

 to Fabricius. As regards this point, only the dates of published me- 

 moirs are to be considered, notwithstanding the assertion of Fabricius 

 that he had seen the valves in 15/4. In 1545, Etienne described, in 

 branches of the portal vein, " valves, which he called apophyses, and 

 which he compared to the valves of the heart." In 1551, Amatus 

 Lusitanus published a letter from Cannanus, in which it is stated that 

 he had found valves in certain of the veins. In 1563, Eustachius pub- 

 lished an account of the valves of the coronary vein. In 1586, a clear 

 account, by Piccolhominus, of the valves of the veins was published. 

 Fabricius gave the most accurate descriptions and delineations of the 

 valves, and his first publication is said to have appeared in 1603. He 

 demonstrated the valves to Harvey, at Padua; and it is probable that 

 this was the origin of the first speculations by Harvey on the mechan- 

 ism of the circulation. 



In the work of Harvey are described first the movements of the 

 heart, which he exposed and studied in living animals. He described 

 minutely all the phenomena that accompany its action; its diastole, 

 when it is filled with blood, and its systole, when the ventricles con- 

 tract simultaneously, and " by an admirable adjustment all the internal 

 surfaces are drawn together, as if with cords, and so is the charge of 

 blood expelled with force." From the description of the action of 

 the ventricles, he passed to the auricles, and showed how these, by 

 their contraction, filled the ventricles with blood. By experiments on 

 serpents and fishes, he proved that the blood fills the heart from the 



