AN ANATOMICAL STUDY ON THE 



a glove or bladder, or like in a drum or long beam, 

 when the stroke and beat occur together, even at 

 the extremities. Aristotle says {De Animal, j. Cap. 

 p), ''The blood of all animals throbs in the veins (ar- 

 teries are meant), and by the pulse is sent everywhere 

 at once.'' And again {J)e Respirat. Cap. /5), ''All 

 veins pulsate together intermittently, because they all 

 depend on the heart. As it is always in intermittent 

 movement, so they move together, intermittently.'' 

 It is to be noted, according to Galen {fie Plac. 

 Hippocr. & Plat., Cap. p), that the ancient philos- 

 ophers referred to the arteries as veins. 



I once had a case in charge which convinced me of 

 this truth. This person had a large pulsating tumor, 

 called an aneurysm, on the right neck where the 

 subclavian artery descends toward the axilla. Caused 



to reach, that the pulse corresponds in all particulars to the heart 

 beat, and it is reasonable to believe Harvey studied and pondered 

 over the problem for a long time. 



Erasistratus noted that the pulse progresses as a wave, but this 

 was denied by Galen. Both Albrecht von Haller (1708-1777), Elementa 

 Physiologiae 1757, tom. i, p. 447, and M.-F.-Xavier Bichat (1771- 

 1802), agreed with Harvey that the pulse is synchronous in all the 

 arteries. Ernst HeinrichWeber(i795-i878)in 1827 first showed a delay 

 in transmission. From his observations, first printed in his Pulsum 

 arteriarum, Leipzig, 1827, one may calculate the velocity of the pulse- 

 wave to be 9.2 meters per second, and its length 3 meters. More re- 

 cent determinations of the velocity show it to be somewhat slower (see 

 W. H. Howell's splendid Physiology, loth Ed., Phila., 1927, p. 527). 

 For an authoritative appreciation of E. H. Weber, consult P. M. 

 Dawson's delightful account in the William Snow Miller Festschrift, 

 the May 1928 issue. Vol. 25, of the Quarterly of the Phi Beta Pi Medical 

 Fraternity. The velocity of blood-flow, in a given vessel, an entirely 

 diflferent proposition, was carefully investigated by Carl Ludwig 

 (1816-1895). 



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