732 THE HARVEIAN ORATION. 



known, records of Harvey's work and labour upon the circulation of 

 the blood. The experiments to which I refer are put upon record in 

 a letter of Harvey's to P. M. Slegel, of date 1651 (see ' Harveii 

 Opera/ ed. 1766, p. 613; ed. Willis, p. 597). They were under- 

 taken with the object of giving a final and happy despatch to all 

 the quibbling objections of Riolanus, 'omnes Riolani circa banc 

 rem altercationes jugulare ;' and they consisted, firstly, in forcing 

 water from the cava into the right ventricle whilst the pulmonary 

 artery, the ' vena arteriosa ' of those days, was ligatured — whereby 

 E-iolanus' suggestion as to the permeability or porosity of the 

 interventricular septum was shown to be untenable ; and, secondly, 

 in forcing water from the pulmonary artery round into the opened 

 left ventricle, whereby the lesser circulation was demonstrated, to 

 use Harvey's own favourite word, avTo\\ria ; or, to use the very 

 words employed by him upon this very occasion, by an 'experi- 

 mentum clcJjvktov a me ' (in his seventy-fourth year) '.nuper et 

 collegis aliquot praesentibus exploratura.' Simple as this experi- 

 ment may seem to us now, I do not think that any apology is 

 required for the drawing of attention to it ; for it is only twenty- 

 eight years ago (see 'Edinburgh Medical and Surgical Journal,' 

 vol. Ixiii. p. ijo) that Dr. Sharpey, to whom our Baly Medal has 

 been so recently and so fitly assigned, had to perform the very 

 closely similar experiment of injecting defibrinated blood into the 

 thoracic aorta, with the very closely similar object of showing that 

 the force of the heart was sufficient to account for the passage of 

 blood through the intestinal and hepatic vascular systems — nay, 

 to perform an all but identical experiment, adding on to it but the 

 means for estimating and reproducing the force put out by the 

 ventricle concerned. If such experiments as these were necessary 

 in 1845, how much more necessary must have been the still 

 simpler experiments of Harvey in 1651 ! At that time, the prestige 

 of Riolanus the younger ' pressed heavily upon mankind.' Harvey 

 himself had called that individual ' anatomicorum coryphaeum ' 

 in 1649 : and, in the very year and letter we are dealing with, he 

 calls him ' celebrem anatomicum/ And Pecquet, the discoverer of 

 the thoracic duct, in his work, also of this selfsame year 1651, 

 the ' Experimenta Nova Anatomica,' a work spoken of by Haller 

 (' Bibliotheca Anatomica,' i. p. 443) as ^nobile opus et inter prae- 

 cipua saeculi decora,' has the following remarkable passage : ' Ita 



