MOTION OF THE HEART AND BLOOD 



for general use, referring not to that specifically 

 used in the coronary arteries and veins, but to the 

 general reserve in the cavities of its auricles and 

 ventricles, since all the others have a blood supply 

 for their own particular use. The heart alone is 

 so situated and constructed as a reservoir and 

 fountain that blood may be apportioned from it 

 and distributed by its beat to all regions according 

 to the size of the artery serving them. 



Moreover, force and effort, such as given by the 

 heart, is needed to distribute and move the blood 

 this way. Blood easily concentrates toward the 

 interior, as drops of water spilled on a table tend to 

 run together, from such slight causes as cold, fear, 

 or horror. It also tends to move from the tiny veins 

 to the intermediate branches and then to the larger 

 veins because of the movements of the extremities 

 and the compression of muscles. So it is more in- 

 clined to move from the periphery toward the in- 

 terior, even though valves offered no opposition 

 to the contrary. Therefore, blood requires force 

 and impulse to be moved from its origin against 

 its inclination into more narrow and cooler channels. 

 Only the heart can furnish this, and in the manner 

 already described. 



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