CIRCULATION OF THE BLOOD. 97 



glides rapidly on, hastening to the heart, there would speedily 

 be a great deficiency of blood did not every part incessantly 

 restore the blood that is incessantly poured into it. Add to 

 this, that by the impulse of the blood which is forced with 

 each stroke into every part of the second and third regions, 

 that which is contained in the pores or interstices is urged into 

 the smaller veins, from which it passes into larger vessels, its 

 motion assisted besides by the motion and pressure of circum- 

 jacent parts ; for from every containing thing compressed and 

 constringed, contained matters are forced out. And thus it is 

 that by the motions of the muscles and extremities, the blood 

 contained in the minor vessels is forced onwards and delivered 

 into the larger trunks. But that the blood is incessantly 

 driven from the arteries into every part of the body, there gives 

 a pulse and never flows back in these channels, cannot be 

 doubted, if it be admitted that with each pulse of the heart all 

 the arteries are simultaneously distended by the blood sent into 

 them ; and as our learned author himself allows that the diastole 

 of the arteries is occasioned by the systole of the heart, and 

 that the blood once out of the heart can never get back into 

 the ventricles by reason of the opposing valves; if I say, our 

 learned author believes that these things are so, it will be, as 

 manifestly true with regard to the force and impulse by which 

 the blood contained in the vessels is propelled into every part of 

 every region of the body. For wheresoever the arteries pulsate, 

 so far must the impulse and influx extend, and therefore is the 

 impulse felt in every part of each several region; for there is 

 a pulse everywhere, to the very points of the fingers and under 

 the nails, nor is there any part of the body where the shooting 

 pain that accompanies each pulse of the artery, and the effort 

 made to effect a solution of the continuity is not experienced 

 when it is the seat of a phlegmon or furuncle. 



But, further, that the blood contained in the pores of the 

 living tissues returns to the heart, is manifest from what we ob- 

 serve in the hands and feet. For we frequently see the hands 

 and feet, in young persons especially, during severe weather, be- 

 come so cold that to the touch they feel like ice, and they are 

 so benumbed and stiffened that they seem scarcely to retain a 

 trace of sensibility or to be capable of any motion; still are they 

 all the while surcharged with blood, and look red or livid. Yet 



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