HARVEY AND THE HEART 



95 



vincing his audience that the blood in the arteries and 

 heart was in a continual state of ebb and flow. The 

 heart and arteries expanded at the same time ; any member 

 of the audience could convince himself of that fact by 

 feeling the impulse of a patient's heart with one hand, 

 and the pulse at the wrist with the other. The heart and 

 arteries expanded and drew the blood into the tissues. 

 There it became laden with sooty vapours. Then the 

 arteries and heart contracted, forcing the blood back 



Troc/iea 



3>up: Caval 

 Vein 



H.Ventricle 



-Pulmonary 

 artery 



- L. Auricle 



L. Ventricle 



Inf: Caval Vein 



Aorta !k.. < <'..!' 



FlG. 26. — A diagram to illustrate what Harvey was taught concerning 

 the use of the heart. 



towards the central parts of the body, the fuliginous or 

 sooty vapours being expressed from the heart into the 

 lungs, and the blood was thus cleansed. The blood ebbed 

 and flowed seventy or eighty times a minute. To ebb 

 and flow was a law of Nature. The waters of the sea 

 ebbed and flowed ; so did the breath, and so therefore 

 did the blood. 



Thus did Fabricius expound his argument to the 

 audience of which young Harvey was one. There did 

 not seem a single flaw in his reasoning ; the human 

 machine was consistently explained — why it had blood, 

 veins, lungs, a heart and arteries, why the arteries could 



