WILLIAM HARVEY, M. D. 71 



distinct from, the blood ": " for " the blood and spirits con- 

 stitute one body (like — whey and butter in milk, or heat in 

 hot water . . .) ." ^^ 



It should be stressed that Harvey in elucidating the formal 

 cause of the heart, as well as the formal cause of the arteries 

 and veins, has obtained the efficient cause of circulation and 

 the basis for a propter quid demonstration. This is the import 

 of his last chapter and his concluding statement quoted above. 



Conclusion 



Although Harvey's discovery of the circulation of the blood 

 was truly revolutionary, its establishment was strictly tradi- 

 tional. Ironically, the greatest opposition to his work came from 

 the traditionalists. What accounts for the paradox? 



Most scholastics of the fifteenth and sixteenth centuries so 

 admired Aristotle that they ended up slaves to his conclusions 

 and caricaturists, rather than disciples, of the methods by 

 which he arrived at them. As a result they were very unpro- 

 ductive in the natural sciences. 



Modern biologists trace their lineage back to three seven- 

 teenth century scientists who revolted from these Aristotelians: 

 Francis Bacon, Rene Descartes ^^ and William Harvey. What 



^^ Harvey, Anatotnical Exercises on the Generation oj Animals, Ex. 51, ed. cit., 

 p. 502. 



^^ Harvey, The Motion of the Heart and Blood, Introduction, ed. cit., p. 12. 



^^ Descartes was one contemporary who had no difficulty accepting Harvey's 

 conclusion. " I need only mention in reply what has been written by a physician 

 in England, who has the honour of having broken the ice on the subject (that the 

 blood's) course amounts precisely to a perpetual motion." (Rene Descartes, 

 A Discourse on Method of Rightly Conducting the Reason and Seeking Truth in 

 the Sciences, Everyman's Library, p. 41). He accepted Harvey's conclusion without 

 difficulty because it fit in with his mechanistic and mathematized method. His 

 method, however, did not protect him from misunderstanding Harvey's demon- 

 stration and almost everything that Descartes further said about the motions of 

 the heart and blood was in error. (Ibid., pp. 37-43) . 



Harvey, of course, was fully cognizant of Descarte's failure and makes this clear 

 in the following passage: ". . . the ingenious and acute Descartes (whose honourable 

 mention of my name demands acknowledgments,) and others ... in my opinion 

 do not observe correctly . . . Descartes does not perceive how much the 

 relaxation and subsidence of the heart and arteries differ from their distention or 



