CHAPTER IX 



THAT THERE IS A CIRCULATION OF THE BLOOD IS 

 CONFIRMED FROM THE FIRST PROPOSITION 



* 



BUT lest any one should say that we give them words 

 only, and make mere specious assertions without any 

 foundation, and desire to innovate without sufficient 

 cause, three points present themselves for confirmation, 

 which being stated, I conceive that the truth I contend 

 for will follow necessarily, and appear as a thing obvious 

 to all. First, the blood is incessantly transmitted by 

 the action of the heart from the vena cava to the 

 arteries in such quantity, that it cannot be supplied 

 from the ingesta, and in such wise that the whole mass 

 must very quickly pass through the organ ; Second, 

 the blood under the influence of the arterial pulse enters 

 and is impelled in a continuous, equable, and incessant 

 stream through every part and member of the body, in 

 much larger quantity than were sufficient for nutrition, 

 or than the whole mass of fluids could supply ; Third, 

 the veins in like manner return this blood incessantly 

 to the heart from all parts and members of the body. 

 These points proved, I conceive it will be manifest 

 that the blood circulates, revolves, propelled and then 

 returning, from the heart to the extremities, from the 

 extremities to the heart, and thus that it performs a 

 kind of circular motion. 



Let us assume either arbitrarily or from experiment, 

 the quantity of blood which the left ventricle of the 

 heart will contain when distended to be, say two ounces, 

 three ounces, one ounce and a half in the dead body 



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