A HISTORY OF SCIENCE 



place of it? It would surely seem more reasonable 

 to have the small perforations in the thin, easily per- 

 meable membrane of the foetus, and the opening in the 

 adult heart, rather than the reverse. From all this 

 Harvey drew his correct conclusions, declaring ear- 

 nestly, " By Hercules, there are no such porosities, and 

 they cannot be demonstrated/' 



Having convinced himself that no intra-ventricular 

 opening existed, he proceeded to study the action of 

 the heart itself, untrammelled by too much faith in 

 established theories, and, as yet, with no theory of his 

 own. He soon discovered that the commonly ac- 

 cepted theory of the heart striking against the chest- 

 wall during the period of relaxation was entirely wrong, 

 and that its action was exactly the reverse of this, the 

 heart striking the chest- wall during contraction. Hav- 

 ing thus disproved the accepted theory concerning the 

 heart's action, he took up the subject of the action of 

 arteries, and soon was able to demonstrate by vivi- 

 section that the contraction of the arteries was not 

 simultaneous with contractions of the heart. His 

 experiments demonstrated that these vessels were sim- 

 ply elastic tubes whose pulsations were "nothing else 

 than the impulse of the blood within them." The 

 reason that the arterial pulsation was not simultaneous 

 with the heart-beat he found to be because of the time 

 required to carry the impulse along the tube. 



By a series of further careful examinations and ex- 

 periments, which are too extended to be given here, he 

 was soon able further to demonstrate the action and 

 course of the blood during the contractions of the 

 heart. His explanations were practically the same as 



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