64 HERBERT ALBERT RATNER 



pulse, which in arterial diastole corresponds to carliac systole, 

 not cardiac diastole; that cardiac systole is the cause of the 

 arterial pulse via the motion it transmits through the blood; 

 and that blood from the right ventricle gets to the left ventricle 

 through the lungs. 



Since " the one action of the heart is the transfusion and pro- 

 pulsion of the blood by mediation of the arteries to the extremi- 

 ties of the body," ^^ the question arises as to where the heart 

 gets the blood which is the subject of its action. The genesis 

 of the belief and the hypothesis that blood circulates is as 

 follows: 



And sooth to say, when I surveyed in various disquisitions by how 

 much abundance blood might be lost from cutting arteries, in 

 dissections and induced experiments in the living; then the sym- 

 metry and magnitude of the vessels that enter and leave the ven- 

 tricles of the heart (for nature doing nothing groundlessly, would 

 never have given them such proportionate magnitudes ground- 

 lessly) , then the ingenious and attentive fitting together of the 

 valves and fibers, and the rest of the heart's fabric and many other 

 things besides, I frequently and seriously bethought me, and long 

 revolved in my mind, by how much abundance blood was trans- 

 mitted, and the like, in how short a time its transmission might be 

 effected, and not finding it possible that this could be supplied by 

 the juices of the ingested aliment without the veins on the one 

 hand becoming drained, and the arteries on the other hand getting 

 ruptured through the excessive charge of blood, unless the blood 

 should somehow find its way from the arteries into the veins, and 

 so return to the right ventricle of the heart; I began to think 

 whether there might not be a motion as it were, in a circle.^® 



Chapter 9 contains the principal demonstration of the cir- 

 culation: 



A fluid of limited quantity kept in 



perpetual motion in one direction is moved circularly. 



And the blood is such a fluid. 



Therefore the blood is moved circularly. 



In this syllogism according to the Aristotelian logic em- 



" Harvey, Works, op. cit., ch. 5, p. 32. ** Ibid., ch. 8, pp. 45-46. 



